Untitled Flashcard Set
EXAM I — COMPLETE FLASHCARDS
Chapters 1–7
CHAPTER 1 — NATURE OF SCIENCE
Flashcard 1
Q: What is a hypothesis?
A: A testable, falsifiable explanation or proposed answer to a scientific question.
Flashcard 2
Q: What is an independent variable?
A: The variable that the experimenter deliberately changes or manipulates.
Flashcard 3
Q: What is a dependent variable?
A: The variable that is measured or observed in response to the independent variable.
Flashcard 4
Q: How do you identify the independent and dependent variables in an experiment?
A: Ask:
Independent variable = What am I changing?
Dependent variable = What am I measuring?
Flashcard 5
Q: What is an experimental condition?
A: A condition in which the independent variable is manipulated so its effect can be tested.
Flashcard 6
Q: What is a control condition?
A: A comparison condition in which the experimental variable is not given/manipulated, allowing you to determine whether the independent variable caused the observed effect.
Flashcard 7
Q: How would you design an experiment to test a hypothesis?
A: Identify the hypothesis, choose an independent variable to manipulate, identify a dependent variable to measure, establish experimental and control conditions, and keep other relevant variables consistent.
CHAPTER 2 — NATURE OF MOLECULES
ATOMS AND ELEMENTS
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Q: What is an atom?
A: The smallest unit of an element that retains the chemical properties of that element.
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Q: What is an element?
A: A substance consisting of atoms that all have the same number of protons.
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Q: What is a molecule?
A: Two or more atoms chemically bonded together.
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Q: What is a compound?
A: A substance made of two or more different elements chemically bonded together.
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Q: How are atoms, elements, molecules, and compounds related?
A: Atoms are the basic units of elements. Atoms can bond together to form molecules. If the bonded atoms contain different elements, the molecule is a compound.
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Q: What defines an element?
A: Its number of protons.
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Q: What is the atomic number?
A: The number of protons in an atom.
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Q: What is atomic mass?
A: The mass of an atom, approximately equal to the total number of protons and neutrons in the atom.
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Q: How do you determine the number of protons?
A: Protons = atomic number.
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Q: How do you determine the number of electrons in a neutral atom?
A: Electrons = protons = atomic number.
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Q: How do you determine the number of neutrons?
A: Neutrons ≈ mass number − atomic number.
Flashcard 19
Q: What is an organic molecule?
A: In this biological context, an organic molecule contains carbon and is generally associated with carbon bonded to hydrogen.
CHEMICAL BONDS
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Q: What is a covalent bond?
A: A chemical bond in which atoms share electrons.
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Q: What is an ionic bond?
A: An attraction between oppositely charged ions that results from the transfer of electrons from one atom to another.
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Q: What is a hydrogen bond?
A: A relatively weak attraction between a partially positive hydrogen and an electronegative atom, usually oxygen or nitrogen.
Flashcard 23
Q: Which is generally strongest: covalent, ionic, or hydrogen bonds?
A: Covalent bonds are generally the strongest of these three types.
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Q: How does an ionic bond form?
A: One atom loses electrons and another gains electrons, producing oppositely charged ions that attract each other.
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Q: What is electronegativity?
A: The tendency of an atom to attract shared electrons toward itself.
Flashcard 26
Q: How does electronegativity create a polar covalent bond?
A: When two atoms share electrons unequally because one atom has a greater electronegativity, the bond develops partial charges.
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Q: What makes a molecule polar?
A: It has an uneven distribution of charge, producing partial positive and partial negative regions.
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Q: How do polarity and charge affect hydrophilicity?
A: Polar and charged substances interact favorably with water and are generally hydrophilic.
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Q: What does hydrophilic mean?
A: Water-loving; able to interact favorably with water.
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Q: What does hydrophobic mean?
A: Water-avoiding; generally nonpolar substances that do not interact favorably with water.
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Q: Why are nonpolar molecules generally hydrophobic?
A: They lack partial charges that can interact favorably with polar water molecules.
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Q: How are hydrogen bonds related to electronegativity?
A: Highly electronegative atoms such as oxygen create partial charges that allow hydrogen bonds to form.
PROPERTIES OF WATER
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Q: Why can water form hydrogen bonds?
A: Oxygen is more electronegative than hydrogen, causing unequal sharing of electrons and partial charges that allow neighboring water molecules to hydrogen-bond.
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Q: What is cohesion?
A: Attraction between molecules of the same substance.
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Q: What is adhesion?
A: Attraction between molecules of different substances.
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Q: How do hydrogen bonds contribute to cohesion in water?
A: Hydrogen bonds attract neighboring water molecules to one another.
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Q: How do cohesion and adhesion help living systems?
A: They contribute to processes such as water movement through plants and the ability of water to interact with surfaces.
Flashcard 38
Q: What is specific heat?
A: The amount of heat energy required to raise the temperature of a substance by a given amount.
Flashcard 39
Q: Why does water have a relatively high specific heat?
A: A large amount of energy is required to disrupt its hydrogen bonds, so water resists rapid temperature changes.
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Q: Why is water's high specific heat important for living organisms?
A: It helps organisms and environments resist rapid temperature changes.
Flashcard 41
Q: What is an acid?
A: A substance that increases the concentration of H⁺ in a solution.
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Q: What is a base?
A: A substance that decreases the concentration of H⁺, often by accepting H⁺ or increasing OH⁻.
Flashcard 43
Q: What is pH?
A: A measure related to the concentration of hydrogen ions, H⁺, in a solution.
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Q: What happens to pH when [H⁺] increases?
A: pH decreases.
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Q: What happens to pH when [H⁺] decreases?
A: pH increases.
Flashcard 46
Q: What happens when HCl is added to water?
A: HCl dissociates, increasing the concentration of H⁺ and Cl⁻. The increased H⁺ lowers the pH.
CHAPTER 3 — BIOMOLECULES
ELEMENTS AND CARBON
Flashcard 47
Q: What are the most common elements in biology listed in the study guide?
A: Carbon (C), oxygen (O), nitrogen (N), sulfur (S), and phosphorus (P).
Flashcard 48
Q: Why is carbon especially important in biological molecules?
A: Carbon can form multiple covalent bonds, allowing it to create diverse molecular structures and large biological molecules.
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Q: What is a hydrocarbon?
A: A molecule composed only of carbon and hydrogen.
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Q: Why are hydrocarbons generally hydrophobic?
A: C–H bonds are relatively nonpolar, so hydrocarbons do not interact strongly with polar water.
Flashcard 51
Q: How do functional groups affect biological molecules?
A: They alter a molecule's chemical properties, including polarity, charge, reactivity, and hydrophobicity.
Flashcard 52
Q: How many covalent bonds can carbon generally form?
A: Four.
ISOMERS
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Q: What are structural isomers?
A: Molecules with the same molecular formula but different arrangements of atoms/bonding patterns.
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Q: What are stereoisomers?
A: Molecules with the same molecular formula and the same bonding arrangement but different three-dimensional arrangements.
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Q: What is the major difference between structural isomers and stereoisomers?
A: Structural isomers differ in how atoms are connected; stereoisomers have the same connectivity but differ in 3-D arrangement.
BIOMOLECULE POLYMERIZATION
Flashcard 56
Q: What reaction is commonly used to form biological polymers from monomers?
A: Dehydration synthesis (condensation), in which water is removed as bonds form.
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Q: What reaction breaks polymers into smaller molecules/monomers?
A: Hydrolysis, in which water is added to break a bond.
Flashcard 58
Q: What role does water play in dehydration synthesis?
A: Water is removed during polymer formation.
Flashcard 59
Q: What role does water play in hydrolysis?
A: Water is added to help break the bond between subunits.
Flashcard 60
Q: What should you know about each biomolecule according to the study guide?
A: Its monomer and monomer structure, which elements react during polymerization, the polymerization reaction, the type of bond formed, and the biomolecule's functions.
CARBOHYDRATES
Flashcard 61
Q: What is the basic chemical formula commonly associated with carbohydrates?
A: Approximately (CH₂O)n.
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Q: What is a monosaccharide?
A: A single sugar unit; the basic building block of carbohydrates.
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Q: What is a disaccharide?
A: Two monosaccharides joined together.
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Q: What is a polysaccharide?
A: A polymer made of many monosaccharide units.
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Q: Where is energy stored in carbohydrates?
A: Chemical energy is stored in their bonds and can be released during metabolic reactions.
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Q: What bond connects monosaccharides?
A: A glycosidic bond.
Flashcard 67
Q: What is the difference between branched and linear polysaccharides?
A: Linear polysaccharides form long continuous chains, whereas branched polysaccharides have chains with branches. Branching can provide more ends where enzymes can act, affecting how quickly stored carbohydrates can be mobilized.
NUCLEIC ACIDS
Flashcard 68
Q: What is the monomer of nucleic acids?
A: A nucleotide.
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Q: What are the three components of a nucleotide?
A: A sugar, a phosphate group, and a nitrogenous base.
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Q: What are the three components of a nucleotide structurally?
A: Five-carbon sugar + phosphate group + nitrogenous base.
Flashcard 71
Q: What is the polymer of nucleotides?
A: A nucleic acid, such as DNA or RNA.
Flashcard 72
Q: What bond connects nucleotides in a nucleic acid strand?
A: Phosphodiester bonds.
Flashcard 73
Q: What sugar is found in DNA?
A: Deoxyribose.
Flashcard 74
Q: What sugar is found in RNA?
A: Ribose.
Flashcard 75
Q: What nitrogenous bases are found in DNA?
A: Adenine (A), thymine (T), cytosine (C), and guanine (G).
Flashcard 76
Q: What nitrogenous bases are found in RNA?
A: Adenine (A), uracil (U), cytosine (C), and guanine (G).
Flashcard 77
Q: What is the major base difference between DNA and RNA?
A: DNA uses thymine; RNA uses uracil.
Flashcard 78
Q: How does DNA generally differ structurally from RNA?
A: DNA is generally double-stranded and contains deoxyribose and thymine. RNA is generally single-stranded and contains ribose and uracil.
Flashcard 79
Q: What are the complementary DNA base-pairing rules?
A: A pairs with T; C pairs with G.
Flashcard 80
Q: What are the RNA base-pairing rules?
A: A pairs with U; C pairs with G.
Flashcard 81
Q: What does antiparallel mean for nucleic acids?
A: The two strands run in opposite directions: one 5′→3′ and the other 3′→5′.
Flashcard 82
Q: What is the polarity of a nucleic acid strand?
A: It has a 5′ end and a 3′ end, and sequences are conventionally written 5′→3′.
Flashcard 83
Q: If a DNA strand is 5′-ATCG-3′, what is the complementary strand?
A: 3′-TAGC-5′.
Flashcard 84
Q: Why does base pairing affect nucleotide prevalence?
A: In double-stranded DNA, each A pairs with T and each C pairs with G, so the amounts of paired bases are related: A = T and C = G.
PROTEINS
Flashcard 85
Q: What is the monomer of a protein?
A: An amino acid.
Flashcard 86
Q: What are the components attached to the central carbon of an amino acid?
A: An amino group, carboxyl group, hydrogen, and R group.
Flashcard 87
Q: What makes one amino acid different from another?
A: Its R group (side chain).
Flashcard 88
Q: What bond connects amino acids?
A: A peptide bond.
Flashcard 89
Q: What is primary protein structure?
A: The specific amino acid sequence of a polypeptide.
Flashcard 90
Q: What is secondary protein structure?
A: Local folding patterns such as α-helices and β-sheets, stabilized primarily by hydrogen bonds involving the peptide backbone.
Flashcard 91
Q: What is tertiary protein structure?
A: The overall three-dimensional shape of a single polypeptide produced by interactions among its R groups and other parts of the molecule.
Flashcard 92
Q: What is quaternary protein structure?
A: The arrangement and interaction of multiple polypeptide subunits in a protein.
Flashcard 93
Q: What interactions contribute to tertiary structure?
A: Interactions among R groups, including hydrophobic interactions, hydrogen bonds, ionic interactions, and disulfide bonds.
Flashcard 94
Q: How does protein structure relate to protein function?
A: A protein's three-dimensional structure determines how it interacts with other molecules and therefore strongly influences its function.
Flashcard 95
Q: How do hydrophobic R groups affect protein folding?
A: In an aqueous environment, hydrophobic R groups tend to be positioned away from water, often toward the protein interior.
Flashcard 96
Q: How do hydrophilic R groups affect protein folding?
A: They can interact favorably with water and are often exposed toward the aqueous environment.
Flashcard 97
Q: What is protein denaturation?
A: Disruption of a protein's normal structure, which can cause loss of function.
Flashcard 98
Q: What levels of protein structure can denaturation affect?
A: It can disrupt secondary, tertiary, and/or quaternary structure. Primary structure is generally not broken by ordinary denaturation because peptide bonds remain intact.
LIPIDS
Flashcard 99
Q: What is the common feature of lipids?
A: Lipids are generally hydrophobic or largely nonpolar molecules and are not defined by a single repeating monomer structure.
Flashcard 100
Q: What is a saturated fatty acid?
A: A fatty acid containing no carbon-carbon double bonds.
Flashcard 101
Q: What is an unsaturated fatty acid?
A: A fatty acid containing one or more carbon-carbon double bonds.
Flashcard 102
Q: How does saturation affect lipid properties?
A: Double bonds in unsaturated fatty acids introduce bends/kinks that affect packing and physical properties. Saturated chains are straighter and can pack more tightly.
Flashcard 103
Q: What are the components of a triglyceride?
A: One glycerol and three fatty acids.
Flashcard 104
Q: What is the function of triglycerides?
A: Long-term energy storage and insulation/protection.
Flashcard 105
Q: What are the components of a phospholipid?
A: A glycerol backbone, two fatty acid tails, and a phosphate-containing polar head group.
Flashcard 106
Q: Why are phospholipids important for membranes?
A: They have hydrophilic heads and hydrophobic tails, causing them to spontaneously organize into bilayers in water.
Flashcard 107
Q: What is a steroid?
A: A lipid characterized by a core structure of four fused carbon rings.
CHAPTER 4 — CELLS
CELL THEORY
Flashcard 108
Q: What are the three elements of cell theory?
A:
All living organisms are composed of one or more cells.
The cell is the basic unit of life.
All cells come from pre-existing cells.
Flashcard 109
Q: What are basic cellular structural features shared by cells?
A: A plasma membrane, cytoplasm/cytosol, genetic material, and ribosomes.
PROKARYOTIC VS. EUKARYOTIC CELLS
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Q: What is a prokaryotic cell?
A: A cell that lacks a membrane-bound nucleus and other membrane-bound organelles.
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Q: What is a eukaryotic cell?
A: A cell containing a membrane-bound nucleus and membrane-bound organelles.
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Q: What features do all cells share?
A: Plasma membrane, genetic material, ribosomes, and cytoplasm.
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Q: What is a major feature unique to eukaryotic cells?
A: A membrane-bound nucleus and membrane-bound organelles.
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Q: What is a major feature of prokaryotic cells?
A: Their DNA is not enclosed in a membrane-bound nucleus.
Flashcard 115
Q: What is a capsule?
A: A specialized outer layer found in some prokaryotes that can help protect the cell and aid attachment.
Flashcard 116
Q: What are flagella?
A: Structures used for movement.
Flashcard 117
Q: What are pili?
A: Hair-like structures on some prokaryotes involved in attachment and, for some pili, DNA transfer.
ORGANELLES
Flashcard 118
Q: What is the nucleus?
A: A membrane-bound organelle that contains most of a eukaryotic cell's DNA and serves as a major site of genetic regulation.
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Q: What is the nuclear envelope?
A: The double membrane surrounding the nucleus.
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Q: What are nuclear pores?
A: Openings in the nuclear envelope that regulate movement of molecules between the nucleus and cytoplasm.
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Q: What is the nuclear lamina?
A: A protein network lining the inner nuclear envelope that provides structural support.
Flashcard 122
Q: What is the nucleolus?
A: A region inside the nucleus where rRNA is produced and ribosomal subunits are assembled.
Flashcard 123
Q: What is a ribosome?
A: A molecular machine that synthesizes proteins by linking amino acids according to information carried by mRNA.
Flashcard 124
Q: What is the rough ER?
A: Endoplasmic reticulum covered with ribosomes; it is involved in synthesis and initial processing of proteins destined for secretion, membranes, or certain organelles.
Flashcard 125
Q: What is the smooth ER?
A: ER lacking ribosomes; it is involved in lipid synthesis and other functions such as detoxification and calcium storage.
Flashcard 126
Q: What types of biomolecules are synthesized in the rough ER?
A: Many proteins, especially proteins destined for secretion, membranes, or the endomembrane system.
Flashcard 127
Q: What types of biomolecules are synthesized in the smooth ER?
A: Many lipids.
Flashcard 128
Q: What is the Golgi apparatus?
A: An organelle that modifies, sorts, and packages proteins and lipids received from the ER.
Flashcard 129
Q: How is the Golgi related to the ER?
A: Transport vesicles carry materials from the ER to the Golgi, where they can be modified and sorted.
Flashcard 130
Q: What are lysosomes?
A: Membrane-bound organelles containing digestive enzymes that break down cellular materials and macromolecules.
Flashcard 131
Q: What are mitochondria?
A: Organelles that carry out most stages of aerobic cellular respiration and produce ATP.
Flashcard 132
Q: What are chloroplasts?
A: Organelles in plants and other photosynthetic eukaryotes where photosynthesis occurs.
Flashcard 133
Q: What do mitochondria and chloroplasts have that supports the endosymbiosis theory?
A: They contain their own DNA and ribosomes and have features consistent with their evolutionary origin as engulfed prokaryotic cells.
Flashcard 134
Q: What is the endosymbiosis theory?
A: The theory that mitochondria and chloroplasts originated from free-living prokaryotes that were engulfed by ancestral cells and eventually became permanent cellular organelles.
CYTOSKELETON
Flashcard 135
Q: What are microfilaments?
A: The thinnest cytoskeletal filaments, primarily composed of actin.
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Q: What are intermediate filaments?
A: Cytoskeletal fibers that provide mechanical strength and structural stability.
Flashcard 137
Q: What are microtubules?
A: Hollow cytoskeletal tubes made of tubulin that help organize the cell, move chromosomes, and provide tracks for intracellular transport.
Flashcard 138
Q: What is a major function of microfilaments?
A: Cell shape and movement, including contraction and movement of the cell cortex.
Flashcard 139
Q: What is a major function of intermediate filaments?
A: Providing tensile strength and resisting mechanical stress.
Flashcard 140
Q: What is a major function of microtubules?
A: Intracellular transport, chromosome movement, and organization of cell structure.
Flashcard 141
Q: How does the cytoskeleton help whole-cell movement?
A: Cytoskeletal elements interact with motor proteins and other cellular structures to produce changes in cell shape and movement.
Flashcard 142
Q: How does the cytoskeleton help intracellular transport?
A: Microtubules and actin filaments provide tracks along which motor proteins move cargo such as vesicles and organelles.
CENTROSOMES
Flashcard 143
Q: What is the role of the centrosome?
A: It acts as a major microtubule-organizing center and helps organize microtubules, especially during cell division.
EXTRACELLULAR MATRIX
Flashcard 144
Q: What is the extracellular matrix (ECM)?
A: A network of molecules outside cells that provides structural support and helps cells interact with their surroundings.
CELL-CELL CONNECTIONS
Flashcard 145
Q: What is the role of surface proteins?
A: They can participate in cell adhesion, communication, recognition, signaling, and interactions with the extracellular environment.
Flashcard 146
Q: What are tight junctions?
A: Cell junctions that create a seal between neighboring cells and restrict movement of substances through the space between cells.
Flashcard 147
Q: What are anchoring junctions?
A: Junctions that mechanically attach cells to one another or to the extracellular matrix.
Flashcard 148
Q: What are gap junctions?
A: Channels between neighboring animal cells that allow small molecules and ions to pass directly from cell to cell.
Flashcard 149
Q: How do the major cell junctions differ?
A:
Tight junctions → seal cells together.
Anchoring junctions → provide mechanical attachment.
Gap junctions → allow direct communication between neighboring cells.
CHAPTER 5 — MEMBRANES
Flashcard 150
Q: What are biological membranes made of?
A: Primarily phospholipids, proteins, and associated carbohydrates.
Flashcard 151
Q: What is a phospholipid?
A: A lipid with a hydrophilic, polar head and hydrophobic fatty acid tails.
Flashcard 152
Q: Why do phospholipids form bilayers in water?
A: Their hydrophilic heads interact with water while their hydrophobic tails avoid water, causing them to organize into two layers with tails facing inward and heads facing outward.
Flashcard 153
Q: What factors affect membrane fluidity?
A: Temperature, fatty-acid chain length, degree of unsaturation, and cholesterol.
Flashcard 154
Q: How do unsaturated fatty acids affect membrane fluidity?
A: Their bends/kinks prevent tight packing and generally increase fluidity.
Flashcard 155
Q: How do saturated fatty acids affect membrane fluidity?
A: Their straighter chains pack more tightly and generally decrease fluidity.
Flashcard 156
Q: How does shorter fatty-acid chain length affect fluidity?
A: Shorter chains generally increase fluidity.
Flashcard 157
Q: How does temperature affect membrane fluidity?
A: Higher temperatures generally increase fluidity; lower temperatures decrease fluidity.
Flashcard 158
Q: What does cholesterol do in a membrane?
A: It helps regulate membrane fluidity and stability.
Flashcard 159
Q: What are membrane proteins used for?
A: Transport, signaling, enzymatic activity, cell recognition, adhesion, and attachment to the cytoskeleton or extracellular matrix.
Flashcard 160
Q: What is an integral membrane protein?
A: A protein embedded in the membrane.
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Q: What is a transmembrane protein?
A: An integral membrane protein that spans the entire lipid bilayer.
Flashcard 162
Q: What is a peripheral membrane protein?
A: A protein associated with the surface of the membrane rather than embedded through the hydrophobic core.
Flashcard 163
Q: What is a transmembrane domain?
A: The portion of a protein that crosses the membrane's hydrophobic interior.
Flashcard 164
Q: What amino acids would you expect in a transmembrane region?
A: Mostly hydrophobic/nonpolar amino acids because the region interacts with the membrane's hydrophobic fatty-acid tails.
Flashcard 165
Q: What amino acids would you expect in an extracellular region exposed to water?
A: More hydrophilic/polar or charged amino acids because they interact with the aqueous environment.
MEMBRANE TRANSPORT
Flashcard 166
Q: What is passive transport?
A: Movement across a membrane that does not require cellular energy input and generally occurs down a concentration/electrochemical gradient.
Flashcard 167
Q: What is active transport?
A: Movement across a membrane that requires energy and can move substances against their concentration/electrochemical gradient.
Flashcard 168
Q: What is simple diffusion?
A: Movement of molecules directly through the lipid bilayer from higher concentration to lower concentration without energy input or a transport protein.
Flashcard 169
Q: What types of molecules commonly cross by simple diffusion?
A: Small nonpolar molecules and some small uncharged molecules.
Flashcard 170
Q: What is facilitated diffusion?
A: Passive movement down a concentration/electrochemical gradient through a membrane protein.
Flashcard 171
Q: What types of molecules require facilitated diffusion?
A: Molecules that cannot readily cross the hydrophobic membrane core but can move down their gradient through a protein, such as ions and many polar molecules.
Flashcard 172
Q: What is an ion channel?
A: A membrane protein that provides a hydrophilic pathway through which specific ions can move down their electrochemical gradients.
Flashcard 173
Q: What is a carrier protein?
A: A membrane protein that binds a specific solute and changes shape to move it across the membrane.
Flashcard 174
Q: What is osmosis?
A: The movement of water across a selectively permeable membrane toward the side with the higher effective solute concentration.
Flashcard 175
Q: What does isotonic mean?
A: Two solutions have equivalent effective solute concentrations, so there is no net movement of water.
Flashcard 176
Q: What does hypertonic mean?
A: A solution has a higher effective solute concentration than the comparison solution.
Flashcard 177
Q: What does hypotonic mean?
A: A solution has a lower effective solute concentration than the comparison solution.
Flashcard 178
Q: In osmosis, which direction does water move?
A: Toward the side with the higher effective solute concentration.
Flashcard 179
Q: How can you determine whether a molecule uses simple diffusion, facilitated diffusion, or active transport?
A: Consider:
Can the molecule cross the lipid bilayer?
Is a transport protein needed?
Is it moving down or against its gradient?
Is energy required?
Flashcard 180
Q: What are the three types of carrier proteins used in active transport?
A: Uniporters, symporters, and antiporters.
Flashcard 181
Q: What is a uniporter?
A: A carrier that transports one type of molecule/ion in one direction.
Flashcard 182
Q: What is a symporter?
A: A carrier that transports two different substances in the same direction.
Flashcard 183
Q: What is an antiporter?
A: A carrier that transports two different substances in opposite directions.
Flashcard 184
Q: What does the Na⁺/K⁺ pump do?
A: It uses ATP to transport Na⁺ and K⁺ against their gradients, typically moving 3 Na⁺ out of the cell and 2 K⁺ into the cell per ATP.
Flashcard 185
Q: What is coupled/indirect active transport?
A: Transport in which the energy stored in an ion's electrochemical gradient drives another substance against its gradient.
Flashcard 186
Q: What are the major types of bulk transport?
A: Endocytosis and exocytosis.
Flashcard 187
Q: What is endocytosis?
A: Movement of material into a cell by forming a vesicle from the plasma membrane.
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Q: What is exocytosis?
A: Movement of material out of a cell when an intracellular vesicle fuses with the plasma membrane.
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Q: What is phagocytosis?
A: A type of endocytosis in which a cell engulfs large particles.
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Q: What is pinocytosis?
A: A type of endocytosis involving uptake of extracellular fluid and dissolved substances.
CHAPTER 6 — METABOLISM
Flashcard 191
Q: What is kinetic energy?
A: Energy associated with motion.
Flashcard 192
Q: What is potential energy?
A: Stored energy resulting from an object's position, structure, or arrangement.
Flashcard 193
Q: What is a redox reaction?
A: A reaction involving transfer of electrons, in which one substance is oxidized and another is reduced.
Flashcard 194
Q: What does oxidation mean?
A: Loss of electrons.
Flashcard 195
Q: What does reduction mean?
A: Gain of electrons.
Flashcard 196
Q: How can you remember oxidation vs. reduction?
A: OIL RIG:
Oxidation Is Loss
Reduction Is Gain
Flashcard 197
Q: What is free energy?
A: Energy available to do useful work under specified conditions.
Flashcard 198
Q: What does a reaction with negative ΔG mean?
A: The reaction releases free energy and is thermodynamically favorable/spontaneous under the specified conditions.
Flashcard 199
Q: What does a reaction with positive ΔG mean?
A: The reaction requires an input of free energy and is not spontaneous under the specified conditions.
Flashcard 200
Q: What is an enzyme?
A: A biological catalyst that speeds up a reaction by lowering its activation energy.
Flashcard 201
Q: What does an enzyme NOT change about a reaction?
A: It does not change the reaction's overall free-energy change or the equilibrium position.
Flashcard 202
Q: What does an enzyme change?
A: It lowers the activation energy, allowing the reaction to proceed more rapidly.
Flashcard 203
Q: What is activation energy?
A: The minimum energy required for reactants to reach the transition state and begin a reaction.
Flashcard 204
Q: How does a reaction proceed differently with an enzyme?
A: The enzyme provides a lower-energy pathway, so the reaction can proceed faster.
Flashcard 205
Q: What is enzyme specificity?
A: An enzyme interacts selectively with particular substrate(s) because of the shape and chemical properties of its active site.
Flashcard 206
Q: What is a substrate?
A: The reactant molecule that binds to an enzyme.
Flashcard 207
Q: What is the active site?
A: The region of an enzyme where the substrate binds and the reaction occurs.
Flashcard 208
Q: How do enzymes bind their substrates?
A: The substrate interacts with the active site through complementary shape and chemical interactions. Binding can involve an induced fit in which the enzyme changes shape slightly around the substrate.
Flashcard 209
Q: What is an activator?
A: A molecule that increases enzyme activity.
Flashcard 210
Q: What is an inhibitor?
A: A molecule that decreases enzyme activity.
Flashcard 211
Q: How can you determine whether a substance is an activator or inhibitor?
A: Determine whether enzyme activity increases or decreases when the substance is present.
Flashcard 212
Q: What is competitive inhibition?
A: An inhibitor competes with the substrate for binding to the enzyme's active site.
Flashcard 213
Q: What is allosteric inhibition?
A: An inhibitor binds at a site other than the active site and changes the enzyme's shape or activity.
Flashcard 214
Q: How can you distinguish competitive and allosteric inhibition?
A:
Competitive → inhibitor binds the active site.
Allosteric → inhibitor binds another site and alters enzyme activity.
Flashcard 215
Q: What is ATP?
A: Adenosine triphosphate, a molecule that stores and transfers usable chemical energy for cellular work.
Flashcard 216
Q: How does ATP store energy?
A: Energy is associated with the chemical arrangement of its phosphate groups and can be released/used when ATP is converted to ADP + phosphate.
Flashcard 217
Q: What is feedback control in a metabolic pathway?
A: Regulation in which a later product of a pathway inhibits an earlier step, helping prevent unnecessary production.
Flashcard 218
Q: Why is feedback inhibition useful?
A: It allows cells to regulate metabolic pathways based on how much final product is already available.
Flashcard 219
Q: In a sequence of metabolic reactions, where would a product become enriched?
A: A molecule can accumulate/enrich when it is produced faster than it is consumed by the next reaction.
CHAPTER 7 — CELLULAR RESPIRATION
Flashcard 220
Q: What is the overall purpose of cellular respiration?
A: To extract energy from molecules such as glucose and capture much of that energy in ATP and reduced electron carriers.
Flashcard 221
Q: What are the four major steps of glucose metabolism/cellular respiration?
A:
Glycolysis
Pyruvate oxidation
Citric acid cycle
Electron transport chain/oxidative phosphorylation
Flashcard 222
Q: Where does glycolysis occur?
A: In the cytosol.
Flashcard 223
Q: What is the carbon balance of glycolysis?
A: One 6-carbon glucose is converted into two 3-carbon pyruvate molecules.
Flashcard 224
Q: What is the net ATP production of glycolysis per glucose?
A: 2 ATP.
Flashcard 225
Q: What is the net NADH production of glycolysis per glucose?
A: 2 NADH.
Flashcard 226
Q: What happens during glycolysis?
A: A 6-carbon glucose molecule is converted through a series of reactions into two 3-carbon pyruvate molecules.
Flashcard 227
Q: How is glycolysis organized according to the study guide?
A: It can be viewed as two sets of five reactions each: an energy-investment phase followed by an energy-payoff phase.
Flashcard 228
Q: What is the purpose of the energy-investment phase of glycolysis?
A: ATP is used to add energy/phosphate groups to intermediates, preparing glucose for later reactions.
Flashcard 229
Q: What happens during the energy-payoff phase of glycolysis?
A: The energized intermediates are converted into pyruvate, producing ATP and NADH.
Flashcard 230
Q: What happens during pyruvate oxidation?
A: Each pyruvate is converted into acetyl-CoA, CO₂ is released, and NAD⁺ is reduced to NADH.
Flashcard 231
Q: What is the carbon balance during pyruvate oxidation?
A: Each 3-carbon pyruvate loses one carbon as CO₂, leaving a 2-carbon acetyl group in acetyl-CoA.
Flashcard 232
Q: What redox reaction occurs during pyruvate oxidation?
A: Electrons are transferred from the oxidized carbon-containing molecule to NAD⁺, producing NADH.
Flashcard 233
Q: Where does pyruvate oxidation occur in eukaryotic cells?
A: In the mitochondrial matrix.
Flashcard 234
Q: What is anaerobic respiration/metabolism?
A: Energy metabolism occurring without oxygen serving as the terminal electron acceptor.
Flashcard 235
Q: What is aerobic respiration?
A: Cellular respiration in which oxygen ultimately serves as the terminal electron acceptor.
Flashcard 236
Q: What is the citric acid cycle?
A: A series of reactions that oxidizes acetyl-CoA-derived carbon and captures energy in NADH, FADH₂, and ATP/GTP while releasing CO₂.
Flashcard 237
Q: How is the citric acid cycle organized according to the study guide?
A: It can be viewed as three sets of reactions.
Flashcard 238
Q: Where does the citric acid cycle occur?
A: In the mitochondrial matrix in eukaryotic cells.
Flashcard 239
Q: What happens to the carbon entering the citric acid cycle?
A: Carbon from acetyl-CoA is eventually released as CO₂.
Flashcard 240
Q: What reduced electron carriers are produced by the citric acid cycle?
A: NADH and FADH₂.
Flashcard 241
Q: What is the function of the electron transport chain?
A: It transfers electrons from reduced electron carriers through a series of membrane proteins, using the released energy to pump protons and create a gradient that drives ATP production.
Flashcard 242
Q: What is the final electron acceptor in aerobic respiration?
A: Oxygen.
Flashcard 243
Q: What happens to oxygen at the end of the electron transport chain?
A: Oxygen accepts electrons and combines with protons to form water.
Flashcard 244
Q: Why are electron acceptors important in glucose metabolism?
A: They accept electrons removed during oxidation reactions, allowing electron transfer and continued metabolism.
Flashcard 245
Q: What happens if NAD⁺ cannot be regenerated?
A: Reactions that require NAD⁺ as an electron acceptor can stop because oxidized electron carriers are unavailable.
Flashcard 246
Q: Where do fats enter energy metabolism?
A: Fatty acids can be broken down into acetyl-CoA through β-oxidation, while glycerol can enter pathways associated with glycolysis.
Flashcard 247
Q: Where can proteins enter energy metabolism?
A: Amino acids can be broken down and their carbon skeletons can enter glycolysis, pyruvate oxidation, or the citric acid cycle at different points.
Flashcard 248
Q: What are control points in cellular respiration?
A: Regulatory steps where the rate of a pathway can be adjusted based on energy needs and concentrations of substrates/products.
Flashcard 249
Q: How can altering an input to cellular respiration affect the pathway?
A: Changing the availability of an input can change the rate and/or amount of products produced downstream.
Flashcard 250
Q: How can altering an output affect cellular respiration?
A: Accumulation of products can inhibit pathway reactions, while removal/use of products can allow the pathway to continue.
Flashcard 251
Q: What is the overall carbon balance for glucose respiration?
A: One 6-carbon glucose molecule is ultimately converted to six CO₂ molecules during complete aerobic oxidation.
Flashcard 252
Q: Where does the CO₂ produced during respiration come from?
A: Carbon atoms from glucose are released as CO₂ primarily during pyruvate oxidation and the citric acid cycle.
Flashcard 253
Q: What happens to the energy from glucose during respiration?
A: It is transferred into ATP and reduced electron carriers such as NADH and FADH₂, which can then drive ATP production.
Flashcard 254
Q: What should you know for each of the four stages of glucose metabolism?
A: Reactants, products, net ATP, net NADH/FADH₂, carbon balance, and cellular location.
EXAM I — COMPREHENSIVE PRACTICE TEST
Chapters 1–7
Do this without looking at the flashcards first.
PART I — NATURE OF SCIENCE
1.
A scientist wants to determine whether fertilizer affects plant growth.
Identify:
The hypothesis
The independent variable
The dependent variable
The experimental condition
The control condition
2.
A scientist changes the amount of fertilizer given to plants and measures their height after four weeks.
What is the independent variable?
A. Plant height
B. Amount of fertilizer
C. Type of plant
D. Four weeks
3.
What makes a hypothesis scientifically useful?
PART II — ATOMS AND CHEMICAL BONDS
4.
Define:
a. Atom
b. Element
c. Molecule
d. Compound
5.
An atom has an atomic number of 17 and a mass number of 35.
How many:
Protons?
Electrons in a neutral atom?
Neutrons?
6.
What determines the identity of an element?
7.
What does electronegativity describe?
8.
Explain the difference between:
Covalent bonds
Ionic bonds
Hydrogen bonds
9.
Rank these bonds from strongest to weakest:
Covalent, hydrogen, ionic
10.
Why does a difference in electronegativity result in a polar covalent bond?
11.
Which molecule would generally be more hydrophilic?
A. A nonpolar hydrocarbon
B. A molecule containing several charged/polar groups
C. A molecule made entirely of C and H
D. A molecule with no partial charges
Explain your answer.
PART III — WATER
12.
Explain why water molecules can form hydrogen bonds with one another.
13.
Define:
a. Cohesion
b. Adhesion
14.
Why does water have a relatively high specific heat?
15.
Why is water's specific heat biologically important?
16.
What happens to [H⁺] when an acid is added?
17.
What happens to pH when [H⁺] increases?
18.
HCl is added to water.
What happens to:
[H⁺]?
pH?
PART IV — BIOMOLECULES
19.
List the five elements identified in the study guide as common in biology.
20.
Why is carbon particularly useful for building biological molecules?
21.
What is a hydrocarbon, and why is it generally hydrophobic?
22.
Explain the difference between structural isomers and stereoisomers.
23.
What type of reaction builds polymers by removing water?
24.
What type of reaction breaks polymers apart by adding water?
CARBOHYDRATES
25.
What is the basic formula associated with carbohydrates?
26.
Define:
a. Monosaccharide
b. Disaccharide
c. Polysaccharide
27.
What bond connects monosaccharides?
28.
What is the difference between a branched and a linear polysaccharide?
29.
How does branching affect the accessibility of a polysaccharide for breakdown?
NUCLEIC ACIDS
30.
What is the monomer of nucleic acids?
31.
Name the three parts of a nucleotide.
32.
Give the major structural differences between DNA and RNA.
33.
Complete the complementary DNA strand:
5′-A T G C C A T-3′
Write the complementary strand with the correct polarity.
34.
Complete the complementary RNA strand:
5′-A U G C C A U-3′
Write the complementary strand with the correct polarity.
35.
What does 5′→3′ describe?
36.
If a double-stranded DNA molecule contains 30% adenine, what percentage is thymine?
37.
If a DNA molecule contains 20% cytosine, what percentage is guanine?
PROTEINS
38.
What is the monomer of proteins?
39.
Name the four groups attached to the central carbon of a generic amino acid.
40.
What part of an amino acid varies among amino acids?
41.
What bond connects amino acids?
42.
Match each level of protein structure with its description:
Primary
Secondary
Tertiary
Quaternary
A. Overall 3-D shape of one polypeptide
B. Amino acid sequence
C. Arrangement of multiple polypeptide chains
D. Local structures such as α-helices and β-sheets
43.
What type of interaction is especially important in secondary structure?
44.
Name at least three interactions that can contribute to tertiary structure.
45.
How can hydrophobic R groups influence tertiary structure?
46.
Why does protein structure matter for protein function?
47.
What is denaturation?
48.
Which levels of protein structure can be disrupted by denaturation?
LIPIDS
49.
What common property characterizes lipids?
50.
What is the difference between a saturated and an unsaturated fatty acid?
51.
How do double bonds affect fatty-acid shape and lipid packing?
52.
What are the components of a triglyceride?
53.
What are the components of a phospholipid?
54.
Why do phospholipids form bilayers in water?
55.
What is the basic structural feature that defines steroids?
PART V — CELLS
56.
List the three parts of cell theory.
57.
Name four basic features shared by all cells.
58.
What is the major difference between prokaryotic and eukaryotic cells?
59.
Which type of cell has a membrane-bound nucleus?
60.
What is the function of:
a. Capsule
b. Flagella
c. Pili
ORGANELLES
61.
What is the main function of the nucleus?
62.
Define:
a. Nuclear envelope
b. Nuclear pores
c. Nuclear lamina
d. Nucleolus
63.
What is the function of ribosomes?
64.
What is the difference between rough ER and smooth ER?
65.
Which type of ER is associated with protein synthesis?
66.
Which type of ER is associated with lipid synthesis?
67.
Describe the pathway connecting the ER, vesicles, and Golgi apparatus.
68.
What is the function of lysosomes?
69.
Compare mitochondria and chloroplasts.
70.
What evidence supports the endosymbiosis theory?
71.
Explain the endosymbiosis theory.
CYTOSKELETON
72.
Name the three major types of cytoskeletal filaments.
73.
Match each with its major function:
Microfilaments
Intermediate filaments
Microtubules
A. Mechanical strength
B. Cell movement/shape
C. Intracellular transport and chromosome movement
74.
How can the cytoskeleton help move materials inside a cell?
75.
How can the cytoskeleton contribute to whole-cell movement?
76.
What is the role of the centrosome?
77.
What is the extracellular matrix?
78.
What are some functions of cell-surface proteins?
79.
Match the junction with its function:
Tight junction
Anchoring junction
Gap junction
A. Direct communication between neighboring cells
B. Sealing neighboring cells together
C. Mechanical attachment
PART VI — MEMBRANES
80.
What are the major components of biological membranes?
81.
Draw or describe the structure of a phospholipid.
82.
Why do phospholipids spontaneously form bilayers in water?
83.
What happens to membrane fluidity when the proportion of unsaturated fatty acids increases?
84.
What happens to membrane fluidity when fatty-acid chains become shorter?
85.
What generally happens to membrane fluidity when temperature increases?
86.
What role does cholesterol play in membranes?
87.
What is the difference between:
Integral membrane proteins
Transmembrane proteins
Peripheral membrane proteins
88.
What is a transmembrane domain?
89.
Would you expect the amino acids in a transmembrane region to be mostly hydrophobic or hydrophilic?
Explain.
90.
Would you expect the amino acids exposed to the extracellular fluid to be mostly hydrophobic or hydrophilic?
Explain.
PART VII — MEMBRANE TRANSPORT
91.
What is the difference between passive and active transport?
92.
A small nonpolar molecule moves from high concentration to low concentration directly through the lipid bilayer.
What type of transport is this?
93.
An ion moves through a membrane protein from high concentration to low concentration.
What type of transport is this?
94.
Why can't most ions simply cross through the lipid bilayer?
95.
What is the difference between an ion channel and a carrier protein?
96.
Water is separated by a selectively permeable membrane. Side A has a lower effective solute concentration than Side B.
Which direction will water move?
97.
Define:
a. Isotonic
b. Hypertonic
c. Hypotonic
98.
A cell is placed in a solution that is hypertonic relative to the cell.
What direction will water move?
99.
Name the three types of carrier proteins.
100.
What is the difference between a uniporter, symporter, and antiporter?
101.
What does the Na⁺/K⁺ pump do?
102.
Does the Na⁺/K⁺ pump use energy?
If so, where does that energy come from?
103.
What is coupled/indirect active transport?
104.
What is endocytosis?
105.
What is exocytosis?
106.
What is phagocytosis?
107.
What is pinocytosis?
PART VIII — METABOLISM
108.
What is the difference between kinetic and potential energy?
109.
What is a redox reaction?
110.
What does oxidation mean?
111.
What does reduction mean?
112.
In the reaction below, identify which substance is oxidized and which is reduced:
A → B + electrons
113.
What is free energy?
114.
What does a negative ΔG indicate?
115.
What does a positive ΔG indicate?
116.
What is an enzyme?
117.
What is activation energy?
118.
How does an enzyme affect activation energy?
119.
Does an enzyme change the overall free-energy change of a reaction?
120.
Does an enzyme change the equilibrium of a reaction?
121.
What is enzyme specificity?
122.
What is a substrate?
123.
What is the active site?
124.
Explain induced fit.
125.
What is an activator?
126.
What is an inhibitor?
127.
If adding substance X causes enzyme activity to increase, is X an activator or inhibitor?
128.
If adding substance Y causes enzyme activity to decrease, is Y an activator or inhibitor?
129.
What is competitive inhibition?
130.
What is allosteric inhibition?
131.
An inhibitor binds directly to the active site and prevents the substrate from binding.
What type of inhibition is this?
132.
An inhibitor binds somewhere other than the active site and changes the enzyme's shape.
What type of inhibition is this?
133.
What is ATP?
134.
What role does ATP play in cellular energy storage and transfer?
135.
What is feedback control?
136.
Why is feedback inhibition useful in metabolic pathways?
PART IX — CELLULAR RESPIRATION
137.
List the four major steps of glucose metabolism.
138.
Where does glycolysis occur?
139.
What molecule enters glycolysis?
140.
What are the major products of glycolysis per glucose?
141.
What is the net ATP production of glycolysis?
142.
What is the net NADH production of glycolysis?
143.
What happens to the six carbons of glucose during glycolysis?
144.
Describe the two broad phases of glycolysis.
145.
Why is ATP initially invested in glycolysis?
146.
What happens during the energy-payoff phase?
147.
What happens during pyruvate oxidation?
148.
Where does pyruvate oxidation occur in eukaryotic cells?
149.
What happens to the carbon lost during pyruvate oxidation?
150.
What electron carrier is reduced during pyruvate oxidation?
151.
What is the difference between aerobic and anaerobic respiration?
152.
What happens during the citric acid cycle?
153.
Where does the citric acid cycle occur?
154.
What reduced electron carriers are produced during the citric acid cycle?
155.
What happens to carbon during the citric acid cycle?
156.
What is the function of the electron transport chain?
157.
What is the final electron acceptor during aerobic respiration?
158.
What is produced when oxygen accepts electrons and protons?
159.
Why are NAD⁺ and FAD important in glucose metabolism?
160.
What happens to cellular respiration if electron acceptors cannot be regenerated?
161.
Where can fats enter energy metabolism?
162.
Where can proteins enter energy metabolism?
163.
What are control points in cellular respiration?
164.
How could changing the availability of an input affect cellular respiration?
165.
How could accumulation of a product affect a metabolic pathway?
166.
How many carbons are present in one glucose molecule?
167.
How many carbons are present in each pyruvate?
168.
How many CO₂ molecules are ultimately produced when one glucose molecule is completely oxidized?
169.
During which stages is CO₂ produced?
170.
Why is the electron transport chain dependent on electron carriers such as NADH and FADH₂?
ANSWER KEY
1–10
Hypothesis = proposed testable explanation; independent variable = fertilizer amount; dependent variable = plant growth/height; experimental = fertilizer treatment; control = no fertilizer or appropriate baseline.
B
It must be testable/falsifiable.
Atom = basic unit of an element; element = substance defined by proton number; molecule = bonded atoms; compound = molecule/substance containing different elements.
17 protons, 17 electrons, 18 neutrons.
Number of protons.
Attraction of an atom for shared electrons.
Covalent = shared electrons; ionic = attraction between ions after electron transfer; hydrogen = weak attraction involving partial charges.
Covalent > ionic > hydrogen, generally.
Electrons are shared unequally.
11–18
B, because polar/charged groups interact favorably with water.
Unequal electron sharing creates partial charges.
Cohesion = same substance; adhesion = different substances.
Hydrogen bonds require energy to disrupt.
It buffers against rapid temperature changes.
[H⁺] increases.
pH decreases.
[H⁺] increases; pH decreases.
19–29
C, O, N, S, P.
Carbon can form four covalent bonds and diverse structures.
Carbon + hydrogen; generally nonpolar/hydrophobic.
Structural = different connectivity; stereoisomers = same connectivity, different 3-D arrangement.
Dehydration synthesis.
Hydrolysis.
Approximately (CH₂O)n.
One, two, and many sugar units respectively.
Glycosidic bond.
Linear = continuous chain; branched = chain with branches.
Branching creates more accessible ends for enzymes.
30–37
Nucleotide.
Sugar, phosphate, nitrogenous base.
DNA: deoxyribose, thymine, generally double-stranded. RNA: ribose, uracil, generally single-stranded.
3′-T A C G G T A-5′.
3′-U A C G G U A-5′.
Direction/polarity of the nucleic acid strand.
30%.
20%.
38–55
Amino acid.
Amino group, carboxyl group, hydrogen, R group.
R group.
Peptide bond.
1-B, 2-D, 3-A, 4-C.
Hydrogen bonding involving the backbone.
Hydrophobic interactions, hydrogen bonds, ionic interactions, disulfide bonds.
They tend to avoid water and can contribute to the protein interior.
Shape determines interactions and therefore function.
Disruption/loss of normal protein structure.
Secondary, tertiary, and/or quaternary; primary generally remains intact.
Generally hydrophobic/nonpolar.
Saturated = no C=C; unsaturated = one or more C=C.
Double bonds create bends/kinks and affect packing.
Glycerol + 3 fatty acids.
Glycerol + 2 fatty acids + phosphate-containing head.
Hydrophilic heads face water; hydrophobic tails avoid water.
Four fused carbon rings.
56–79
All organisms consist of cells; cell is basic unit of life; cells arise from pre-existing cells.
Plasma membrane, genetic material, ribosomes, cytoplasm.
Prokaryotes lack a membrane-bound nucleus; eukaryotes have one.
Eukaryotic.
Capsule = protection/attachment; flagella = movement; pili = attachment/DNA transfer depending on type.
Houses most DNA and regulates genetic activity.
Nuclear envelope = double membrane; pores = transport openings; lamina = structural network; nucleolus = ribosome-subunit production.
Protein synthesis.
Rough ER has ribosomes and synthesizes many proteins; smooth ER lacks ribosomes and synthesizes many lipids.
Rough ER.
Smooth ER.
ER → transport vesicles → Golgi → modification/sorting → destination.
Digestion/breakdown of cellular materials.
Mitochondria = cellular respiration; chloroplasts = photosynthesis.
Own DNA, ribosomes, and other prokaryote-like characteristics.
Organelles originated from engulfed prokaryotic cells.
Microfilaments, intermediate filaments, microtubules.
Microfilaments-B; intermediate filaments-A; microtubules-C.
Filaments provide tracks for motor proteins.
Cytoskeletal rearrangements and motor proteins generate movement.
Microtubule-organizing center.
Network outside cells providing support and interactions.
Adhesion, signaling, recognition, communication, attachment.
1-B, 2-C, 3-A.
80–107
Lipids, proteins, carbohydrates.
Polar/hydrophilic head + nonpolar/hydrophobic tails.
Hydrophilic heads interact with water while hydrophobic tails avoid it.
Increases fluidity.
Generally increases fluidity.
Generally increases fluidity.
Regulates fluidity/stability.
Integral = embedded; transmembrane = spans bilayer; peripheral = associated with surface.
Protein region crossing hydrophobic membrane core.
Hydrophobic.
Hydrophilic/polar/charged.
Passive = no energy input, down gradient; active = energy-dependent, can move against gradient.
Simple diffusion.
Facilitated diffusion.
Charged particles are unfavorable in the hydrophobic membrane interior.
Channel = hydrophilic pore; carrier = binds solute and changes shape.
A → B.
Same effective solute concentration; higher; lower.
Water leaves the cell toward the hypertonic solution.
Uniporter, symporter, antiporter.
One substance; two same direction; two opposite directions.
Uses ATP to move 3 Na⁺ out and 2 K⁺ in.
Yes, ATP.
Energy from one gradient drives another substance against its gradient.
Bringing material into the cell via vesicles.
Releasing material by vesicle fusion.
Engulfing large particles.
Uptake of extracellular fluid/dissolved substances.
108–136
Kinetic = motion; potential = stored energy.
Electron-transfer reaction.
Loss of electrons.
Gain of electrons.
A is oxidized.
Energy available to do useful work.
Energy-releasing/favorable under specified conditions.
Energy input required.
Biological catalyst.
Minimum energy needed to initiate a reaction.
Lowers it.
No.
No.
Selective interaction with particular substrates.
Reactant acted on by an enzyme.
Region where substrate binds/reaction occurs.
Enzyme changes shape slightly when substrate binds.
Increases enzyme activity.
Decreases enzyme activity.
Activator.
Inhibitor.
Competes for active site.
Binds elsewhere and changes enzyme activity.
Competitive.
Allosteric.
Adenosine triphosphate.
Transfers usable energy for cellular work.
Regulation involving pathway products and earlier reactions.
Prevents unnecessary production and conserves resources.
137–170
Glycolysis; pyruvate oxidation; citric acid cycle; electron transport chain/oxidative phosphorylation.
Cytosol.
Glucose.
2 pyruvate, 2 ATP net, 2 NADH.
2 ATP.
2 NADH.
6 carbons → two 3-carbon pyruvates.
Energy investment + energy payoff.
To energize intermediates and prepare glucose for breakdown.
ATP and NADH are produced while pyruvate is formed.
Pyruvate → acetyl-CoA + CO₂; NAD⁺ → NADH.
Mitochondrial matrix.
Released as CO₂.
NAD⁺ → NADH.
Aerobic uses oxygen as final electron acceptor; anaerobic does not.
Oxidizes acetyl-CoA-derived carbon and generates reduced electron carriers.
Mitochondrial matrix.
NADH and FADH₂.
Released as CO₂.
Transfers electrons and establishes a proton gradient used for ATP production.
Oxygen.
Water.
They accept electrons during oxidation reactions.
Oxidative reactions requiring those carriers can stop or slow dramatically.
Fatty acids → acetyl-CoA; glycerol → glycolytic intermediates.
Carbon skeletons enter glycolysis, pyruvate oxidation, or the citric acid cycle.
Regulatory points controlling pathway rate.
It can alter pathway rate and downstream products.
Products can inhibit earlier reactions or slow the pathway.
Six.
Three.
Six CO₂.
Pyruvate oxidation and citric acid cycle.
They carry high-energy electrons to the electron transport chain, where their electrons help drive proton pumping and ATP production.