BIO101 Vocabulary Flashcards
Short-Answer Study Questions for BIO101
Atomic Structure and Bonds
Atomic Number:
Represents the number of protons in an atom's nucleus, defining the element.
Calculation of Neutrons:
Number of neutrons = Atomic Mass - Atomic Number.
Isotope:
Variants of a chemical element that have the same number of protons but different numbers of neutrons.
Atomic Mass:
The weighted average mass of an element’s isotopes, expressed in atomic mass units (amu).
Covalent Bond:
A chemical bond formed by the sharing of electron pairs between atoms.
Nonpolar Covalent Bond:
A type of covalent bond where electrons are shared equally between two atoms, resulting in no charge difference.
Polar Covalent Bond:
A covalent bond in which electrons are shared unequally, resulting in partial positive and negative charges on the atoms.
Ionic Bond:
A bond formed when one atom transfers electrons to another atom, creating ions that attract each other due to opposite charges.
Hydrogen Bond:
A weak attraction between a hydrogen atom bonded to a highly electronegative atom and another electronegative atom.
Weakest Bond:
Hydrogen bond is the weakest of the three: ionic, covalent, or hydrogen.
Electronegativity:
A measure of an atom's ability to attract and hold onto electrons in a chemical bond.
Molecule:
A group of two or more atoms bonded together, representing the smallest fundamental unit of a chemical compound.
Compound:
A substance formed when two or more different elements combine in fixed proportions through chemical bonds.
Chemical Reaction:
A process in which reactants are transformed into products, involving the making and breaking of chemical bonds.
Reactant:
A substance that takes part in and undergoes change during a reaction.
Product:
The substance that is formed as the result of a chemical reaction.
pH:
A measure of how acidic or basic a solution is on a scale of 0 to 14, with 7 being neutral.
Acid:
A substance that donates protons (H+) in a solution, resulting in a pH less than 7.
Base:
A substance that accepts protons or donates hydroxide ions (OH-) in a solution, resulting in a pH greater than 7.
Buffer:
A solution that resists changes in pH when small amounts of acid or base are added, stabilizing the pH of biological systems.
Entropy:
A measure of disorder or randomness in a system, often associated with the Second Law of Thermodynamics.
Exergonic Reaction:
A chemical reaction that releases energy, often in the form of heat.
Endergonic Reaction:
A chemical reaction that requires energy input to proceed.
Heating Virus:
Heating a virus denatures its proteins, leading to loss of function and inactivation.
Dehydration Synthesis Reaction:
A chemical reaction that joins monomers to form polymers by removing water.
Hydrolysis:
A chemical reaction in which water is used to break down polymers into monomers.
Solute:
The substance that is dissolved in a solution.
Solvent:
The substance that dissolves a solute, forming a solution.
Solution:
A homogeneous mixture of two or more substances.
Polarity:
The distribution of electrical charge over the atoms in a molecule, leading to distinct positive and negative ends.
Cohesion of Water:
Water molecules are attracted to each other due to hydrogen bonding, resulting in high surface tension.
Adhesion:
The attraction between water molecules and other substances, allowing water to adhere to surfaces.
Universal Solvent:
Water is called the “universal solvent” because it can dissolve a wide variety of substances due to its polarity.
Concentration Gradient:
A difference in the concentration of a substance across a space, usually leading to diffusion.
Transport Mechanisms
Passive Transport:
The movement of substances across a cell membrane without the use of energy, following the concentration gradient.
Organic Molecule:
Molecules that contain carbon and are found in living organisms.
Elements in Organic Molecules:
All organic molecules contain carbon (C), hydrogen (H), and often oxygen (O), nitrogen (N), sulfur (S) and phosphorus (P).
Four Major Macromolecules:
Carbohydrates, proteins, lipids, and nucleic acids.
Monomers of Carbohydrates:
Monosaccharides, such as glucose and fructose, which combine to form larger carbohydrates (polysaccharides).
Polysaccharides:
Carbohydrates formed by long chains of monosaccharides, such as starch, glycogen, and cellulose.
Monomers of Proteins:
Amino acids, which link together through peptide bonds to form proteins.
Peptide Bonds:
Covalent bonds formed between amino acids during protein synthesis.
Protein Denaturation:
The unfolding or alteration of a protein's structure, leading to loss of function, often due to changes in pH or temperature.
Monomers of Nucleic Acids:
Nucleotides, which are the building blocks of DNA and RNA.
Lipids:
Hydrophobic molecules that are insoluble in water, including fats, oils, and steroids.
Phospholipids:
Major components of cell membranes, having hydrophilic heads and hydrophobic tails.
Cholesterol:
A type of lipid that helps to maintain membrane fluidity and is a precursor for steroid hormones.
Enzyme:
Biological catalysts that accelerate chemical reactions without being consumed.
Active Site:
The region on an enzyme where substrate molecules bind and undergo a chemical reaction.
Substrate Specificity:
The ability of an enzyme to select and bind to a specific substrate for catalysis.
Factors Affecting Enzyme Activity:
Temperature, pH, substrate concentration, and the presence of inhibitors or activators.
Genetic Mutations
Mutation:
A change in the DNA sequence that can result in altered protein function or expression.
Point Mutation:
A mutation that involves a change in a single nucleotide base in DNA.
Frameshift Mutation:
A mutation caused by insertions or deletions of nucleotides that shift the reading frame of the genetic code.
Deletion Mutation:
A mutation where one or more nucleotides are removed from the DNA sequence.
Insertion Mutation:
A mutation where one or more extra nucleotides are added into the DNA sequence.
Silent Mutation:
A mutation that does not lead to a change in the protein product.
Nonsense Mutation:
A mutation that creates a premature stop codon in the coding sequence, resulting in a truncated protein.
Missense Mutation:
A mutation that results in the substitution of one amino acid for another in the protein sequence.
Three-Nucleotide Insertions Avoiding Frameshifts:
If three nucleotides are inserted, it adds one amino acid to the sequence but does not change the reading frame.
Cell Structure and Function
Two Major Cell Types:
Prokaryotic and eukaryotic cells.
Structures Found in All Cells:
Plasma membrane, cytoplasm, ribosomes, and genetic material (DNA).
Plasma Membrane:
A selectively permeable barrier that surrounds the cell, composed of a lipid bilayer with embedded proteins.
Cytoplasm:
The jelly-like fluid that fills the interior of the cell, providing a medium for biochemical reactions.
Cytosol:
The liquid portion of the cytoplasm, excluding organelles and other structures.
Nucleus:
The membrane-bound organelle that houses the cell's DNA and regulates gene expression.
Nucleolus:
A dense region within the nucleus where ribosomal RNA (rRNA) is synthesized.
Ribosomes:
Complexes of rRNA and proteins that synthesize proteins by translating messenger RNA (mRNA).
Rough Endoplasmic Reticulum (ER):
A type of ER with ribosomes attached, involved in protein synthesis and processing.
Smooth Endoplasmic Reticulum (ER):
A type of ER without ribosomes, involved in lipid synthesis and detoxification processes.
Golgi Apparatus:
An organelle that modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
Lysosomes:
Membrane-bound organelles containing digestive enzymes to break down waste materials and cellular debris.
Peroxisomes:
Organelles that detoxify harmful substances and metabolize fatty acids.
Mitochondrion:
The powerhouse of the cell, responsible for producing ATP through cellular respiration.
Mitochondrial DNA:
DNA found in mitochondria that is inherited maternally and encodes some proteins required for mitochondrial function.
Chloroplasts:
Organelles in plant cells that carry out photosynthesis, converting light energy into chemical energy.
Chloroplast DNA:
DNA within chloroplasts that is also inherited maternally, encoding essential proteins for the chloroplast's function.
Stroma:
The fluid-filled space inside chloroplasts where the Calvin cycle occurs.
Thylakoid:
Membrane-bound structures within chloroplasts that are the site of the light-dependent reactions of photosynthesis.
Granum:
A stack of thylakoids within the chloroplasts, interconnected by stroma thylakoids.
Pigments in Thylakoids:
Contain chlorophyll, which absorbs light energy for photosynthesis.
Cytoskeleton:
A network of protein filaments and tubules that provide structure, shape, and facilitate movement in the cell.
Microtubules:
Hollow tubes composed of tubulin that are involved in cell shape, transport within cells, and cell division (spindle formation).
Microfilaments:
Thin, flexible strands composed of actin that are involved in muscle contraction and cell movement.
Intermediate Filaments:
Protein fibers that provide structural support and help to anchor organelles in place.
Centrosome:
An organelle that serves as the main microtubule organizing center (MTOC) of the cell.
Centriole:
A cylindrical structure involved in the formation of the spindle fibers during cell division.
Vacuole:
A membrane-bound compartment within cells that stores materials such as water, ions, and nutrients.
Cell Wall:
A rigid outer layer that provides support and protection to plant cells, composed mainly of cellulose.
Plasmodesmata:
Channels between plant cells that facilitate cell communication and transport of substances.
Gap Junctions:
Intercellular connections that allow for direct communication between adjacent animal cells.
Tight Junctions:
Connections that create a seal between neighboring cells, preventing leakage of extracellular fluid.
Desmosomes:
Strengthening junctions that anchor adjacent cells together in tissues subjected to mechanical stress.
Endosymbiosis Theory:
The theory that certain organelles, such as mitochondria and chloroplasts, originated from free-living prokaryotes that were engulfed by ancestral eukaryotic cells.
Evidence of Endosymbiosis:
Presence of double membranes, their own DNA, and similarities to prokaryotic cells.
Transport Processes in Cells
Osmosis:
The diffusion of water molecules across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration.
Diffusion:
The passive movement of molecules from an area of higher concentration to an area of lower concentration.
Facilitated Diffusion:
The passive transport of molecules across a membrane via protein channels or carriers.
Active Transport:
The movement of substances against their concentration gradient, requiring energy (ATP).
Sodium-Potassium Pump:
A type of active transport mechanism that moves sodium ions out of the cell and potassium ions into the cell against their concentration gradients.
Endocytosis:
The process by which cells engulf external substances, forming vesicles to bring materials into the cell.
Exocytosis:
The process of vesicles fusing with the cell membrane to release their contents outside the cell.
Phagocytosis:
A type of endocytosis in which a cell engulfs large particles or other cells.
Pinocytosis:
A type of endocytosis in which a cell takes in extracellular fluid and dissolved solutes.
Receptor-Mediated Endocytosis:
A selective form of endocytosis that involves receptor proteins on the cell surface binding to specific ligands.
Effects of Tonicity on Cells
Hypertonic Solution:
A solution that has a higher concentration of solutes than the inside of the cell, causing the cell to lose water and potentially shrivel.
Hypotonic Solution:
A solution that has a lower concentration of solutes than the inside of the cell, causing the cell to gain water and potentially burst.
Isotonic Environment:
A situation where the concentration of solutes is equal inside and outside the cell, resulting in no net movement of water.
Plant Cells in Hypotonic Solution:
Do not burst because of the rigid cell wall that maintains structure and can withstand internal pressure.
Turgor Pressure:
The pressure exerted by water inside the central vacuole against the cell wall, providing structural support to plant cells.
Plasmolysis:
The process in which cells lose water in a hypertonic solution, causing the cytoplasm to shrink away from the cell wall.
Ligand:
A molecule that binds to a receptor to elicit a cellular response.
Receptor Protein:
Proteins present on the cell surface that bind specific ligands, leading to signal transduction.
Signal Transduction:
The process by which a cell responds to signals or stimuli, converting an external signal into a functional response.
Hormone:
A signaling molecule produced by glands that controls and regulates physiological processes.
Second Messenger:
A molecule that transmits signals received at a receptor on the cell's surface to target molecules inside the cell, amplifying the signal.
Cyclic AMP (cAMP):
A common second messenger involved in transmitting signals from hormones and other substances to elicit a response within the cell.
Apoptosis:
A programmed process of cell death that occurs naturally in development and maintenance of tissues.
Processes Requiring ATP:
Active transport, muscle contraction, biosynthesis, and cellular signaling processes.
Membrane Fluidity:
The viscosity of the lipid bilayer of a cell membrane, affecting its permeability and the mobility of embedded proteins.
Photosynthesis and Cellular Respiration
Photosynthesis:
The process by which green plants, algae, and some bacteria convert light energy into chemical energy, stored as glucose.
General Equation for Photosynthesis:
6CO2 + 6H2O + light
ightarrow C6H{12}O6 + 6O2
Two Major Stages of Photosynthesis:
Light-dependent reactions and the Calvin cycle (light-independent reactions).
Light-Dependent Reactions:
Occur in the thylakoid membranes, converting light energy to chemical energy (ATP and NADPH) and releasing oxygen.
Calvin Cycle:
Occurs in the stroma, using ATP and NADPH to convert CO2 into glucose.
Location of Light Reactions:
Thylakoid membranes in chloroplasts.
Location of Calvin Cycle:
Stroma of chloroplasts.
Photolysis:
The process of splitting water molecules into oxygen, protons, and electrons during the light-dependent reactions.
Chemiosmosis:
The process in which the movement of protons through ATP synthase generates ATP during the light-dependent reactions.
Photosystem I and II:
Protein-pigment complexes in the thylakoid membranes involved in capturing light energy for photosynthesis.
Chlorophyll:
A pigment responsible for the green color in plants; absorbs light primarily in the blue and red wavelengths for photosynthesis.
Plants’ Green Color:
Due to the absorption of other wavelengths of light by chlorophyll, reflecting green light.
Cellular Respiration:
The process by which cells break down glucose and other organic molecules to produce ATP.
General Equation for Cellular Respiration:
C6H{12}O6 + 6O2
ightarrow 6CO2 + 6H2O + ATP
Glycolysis:
The initial process of breaking down glucose into pyruvate, occurring in the cytoplasm.
Location of Glycolysis:
Cytoplasm of the cell.
Pyruvate Oxidation:
The conversion of pyruvate to acetyl-CoA, linking glycolysis to the Krebs cycle.
Krebs Cycle:
A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA.
Location of Krebs Cycle:
Mitochondrial matrix.
Electron Transport Chain (ETC):
A series of protein complexes in the inner mitochondrial membrane, facilitating electron transfer and proton pumping for ATP production.
Location of ETC:
Inner mitochondrial membrane.
ATP Synthase:
An enzyme that uses the proton gradient created by the ETC to synthesize ATP from ADP and inorganic phosphate.
Oxidative Phosphorylation:
The process of generating ATP from ADP with the energy released by electrons as they transfer through the ETC.
Anaerobic Respiration:
A form of respiration that occurs without oxygen, resulting in less energy production compared to aerobic respiration.
Lactic Acid Fermentation:
An anaerobic process that converts glucose to lactic acid, occurring in some bacteria and muscle cells.
Alcoholic Fermentation:
An anaerobic process where yeast converts sugars into alcohol and carbon dioxide.
Sugar Fermentation Speed:
Yeast ferments glucose the fastest compared to other sugars.
NADH:
Nicotinamide adenine dinucleotide; an electron carrier that transports electrons during cellular respiration.
FADH₂:
Flavin adenine dinucleotide; another electron carrier involved in the Krebs cycle and ETC.
Substrate-Level Phosphorylation:
The direct generation of ATP from ADP by transferring a phosphate group during glycolysis and the Krebs cycle.
Chemiosmotic ATP Production:
ATP production linked to the generation of an electrochemical gradient across a membrane, primarily during oxidative phosphorylation.
Total ATP Yield from One Glucose:
Approximately 30-32 ATP molecules are produced from one molecule of glucose during cellular respiration.
Metabolic Rate:
The rate at which an organism converts nutrients into energy or uses energy for growth and maintenance.
Factors Affecting Respiration Rate:
Temperature, availability of oxygen, nutrient availability, and metabolic demand of the organism.
Oxygen Requirement for Mitochondria:
Mitochondria require oxygen to act as the final electron acceptor in the ETC, essential for aerobic respiration.
Cell Cycle and Reproduction
Cell Cycle:
The series of phases that cells go through to grow and divide, including interphase and mitotic phase.
G₁ Phase:
The first stage of interphase where the cell grows and synthesizes proteins, organelles, and other molecules.
S Phase:
The phase of interphase where DNA replication occurs, resulting in two identical copies of each chromosome.
G₂ Phase:
The second gap phase of interphase where further growth occurs and the cell prepares for mitosis.
Mitosis:
The process by which a single cell divides into two identical daughter cells, ensuring equal distribution of chromosomes.
Prophase:
The first stage of mitosis where chromatin condenses into visible chromosomes, the nuclear envelope breaks down, and spindle fibers form.
Metaphase:
The stage of mitosis where chromosomes align at the cell's equatorial plane.
Anaphase:
The stage of mitosis where sister chromatids separate andMove apart toward opposite poles of the cell.
Telophase:
The final stage of mitosis where chromosomes de-condense, and nuclear envelopes reform around the separated chromatids.
Cytokinesis:
The process that follows mitosis, resulting in the physical division of the cytoplasm and the formation of two distinct daughter cells.
Importance of Mitosis:
Essential for growth, tissue repair, and asexual reproduction in organisms.
Meiosis:
A specialized form of cell division that reduces the chromosome number by half, producing gametes (sperm and eggs).
Crossing-Over:
The exchange of genetic material between homologous chromosomes during meiosis, leading to genetic diversity.
Tetrad:
A structure formed during meiosis, consisting of two homologous chromosomes, each made up of two sister chromatids.
Timing of Crossing-Over:
Occurs during prophase I of meiosis.
Nondisjunction:
An error during cell division that results in the unequal distribution of chromosomes, leading to aneuploidy.
Gamete:
A haploid reproductive cell that can fuse with another gamete during fertilization to form a zygote.
Zygote:
The diploid cell resulting from the fusion of two haploid gametes; the initial stage of development in sexually reproducing organisms.
Necessity of Meiosis for Sexual Reproduction:
It generates genetic diversity through recombination and reduces the chromosome number to maintain stable genome size in offspring.
Spindle Apparatus:
A structure made of microtubules that separates chromosomes during cell division.
Centromere:
The region of a chromosome where sister chromatids are joined and where the spindle fibers attach during mitosis.
Haploid vs. Diploid:
Haploid (n) cells have one set of chromosomes, while diploid (2n) cells have two sets of chromosomes.
Gene:
A segment of DNA that encodes information for the synthesis of a specific protein or function.
Allele:
Different versions of the same gene that may produce variations in traits.
Homozygous:
An organism that has two identical alleles for a particular gene.
Heterozygous:
An organism that has two different alleles for a particular gene.
Genotype:
The genetic makeup of an individual; specifies the alleles present at a particular gene locus.
Phenotype:
The observable physical or biochemical characteristics of an organism as determined by its genotype and environment.
Codominance:
A genetic situation where both alleles in a heterozygote contribute to the phenotype, resulting in expression of both traits.
Incomplete Dominance:
A genetic situation in which one allele does not completely dominate another allele, resulting in a blend of traits.
Epistasis:
A phenomenon in which the expression of one gene is influenced by one or more other genes.
Pleiotropy:
The ability of a single gene to affect multiple traits or phenotypic characteristics.
Polygenic Inheritance:
A pattern of inheritance in which multiple genes contribute to a single trait, leading to a continuous distribution of phenotypes.
Monohybrid Cross:
A genetic cross involving a single trait with two alleles, establishing the principles of inheritance.
Dihybrid Cross:
A genetic cross involving two traits, each with two alleles, to study the inheritance patterns of both traits simultaneously.
Mendel's Law of Segregation:
States that alleles segregate independently of one another when gametes are formed, leading to genetic variation.
Mendel's Law of Independent Assortment:
States that the alleles for different traits are passed independently of one another from parents to offspring.
X-Linked Inheritance:
Patterns of inheritance associated with genes located on the X chromosome, which exhibit unique ratios in males and females.
X-Linked Disorders in Males:
Occur more frequently in males because they have only one X chromosome (XY), meaning that a single recessive allele can express the disorder.
Sex Determination in Humans:
Determined by the presence of Y chromosome (XY = male, XX = female).
Hardy–Weinberg Equilibrium:
A principle that describes the genetic variation in a population that remains constant from one generation to the next in the absence of evolutionary influences.
2pq in Hardy-Weinberg:
Represents the frequency of heterozygous individuals in a population, where p = frequency of the dominant allele and q = frequency of the recessive allele.