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What are the two major domains of prokaryotes?
Bacteria and Archaea
What are the key characteristics of prokaryotic cells?
No nucleus, DNA in the nucleoid region, no membrane-bound organelles, always unicellular.
What are the main characteristics of eukaryotic cells?
Have a nucleus, membrane-bound organelles, can be multicellular or unicellular.
What is the primary function of ribosomes?
Protein synthesis
What are the four types of eukaryotic organisms?
animals, plants, fungi, and protozoa.
What structures are found in both prokaryotes and eukaryotes?
Plasma membrane, cytoplasm, ribosomes, and DNA.
What is the role of ribosomes in the cell?
Responsible for protein synthesis.
What is the function of the nucleus?
Stores DNA and controls the cell's activities.
What is the endomembrane system?
A system of membranes within the cell that includes organelles like the nucleus, ER, Golgi apparatus, and vesicles
What are the two types of ER, and what do they do?
Rough ER (protein synthesis), Smooth ER (lipid and carbohydrate synthesis).
What is the Golgi apparatus responsible for?
Modifying, sorting, and packaging proteins and lipids for transport.
What are lysosomes?
Organelles that contain enzymes to break down waste and cellular debris.
What is the role of the mitochondria?
Cellular respiration, producing ATP (energy) for the cell.
What is the significance of mitochondrial DNA?
It is circular, similar to bacterial DNA, supporting the endosymbiotic theory.
What is the function of chloroplasts in plant cells?
conduct photosynthesis to convert sunlight into chemical energy.
What is the central vacuole, and where is it found?
A large storage organelle in plant cells that holds water, nutrients, and waste.
What is the plasma membrane, and why is it important?
It is the boundary of the cell, controlling what enters and leaves the cell.
What is endosymbiosis?
A theory that mitochondria and chloroplasts were once free-living bacteria that were engulfed by early eukaryotic cells
How do eukaryotic cells differ in energy production compared to prokaryotic cells?
They have mitochondria for cellular respiration, while plants also have chloroplasts for photosynthesis.
What happens to misfolded proteins in the ER?
They are denatured and either degraded or aggregated, which can lead to diseases like Alzheimer’s.
How are proteins transported from the ER to the Golgi apparatus?
Via vesicles, which fuse with the Golgi membrane.
What is cellulose, and where is it found?
A structural polysaccharide in plant cell walls, providing shape and support.
What makes the head region of a lipid polar?
It contains choline, phosphate, and glycerol, all of which are high in electronegativity, making it polar and hydrophilic.
What makes the tail region of a lipid non-polar?
It is composed of hydrocarbons (carbon and hydrogen), which are non-polar and hydrophobic.
What does it mean when a molecule is amphipathic?
It has both polar (hydrophilic) and non-polar (hydrophobic) regions, like phospholipids.
What is the significance of dehydration synthesis in amino acids?
It joins them together by forming peptide bonds, releasing water in the process
What element(s) are present in proteins?
Carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
What is the monomer of proteins?
Amino acids.
What is the unique functional group in proteins?
Sulfhydryl group (–SH)
What are the four levels of protein structure?
Primary (amino acid sequence), Secondary (alpha helices and beta sheets), Tertiary (3D folding of the entire chain.), Quaternary (assembly of multiple chains).
How are the secondary structures of proteins formed?
Through hydrogen bonding between the backbone atoms, creating alpha helices and beta pleated sheets.
What are the two types of secondary structures in proteins?
Alpha helix (coils) and beta pleated sheets (folded back and forth).
What is the importance of the quaternary structure of proteins?
It is the fully functional protein, composed of multiple subunits.
What happens when a protein is denatured?
It loses its shape, making it non-functional, and the change is usually irreversible.
What factors can denature proteins?
Heat, changes in pH, and mutations.
What is an example of a protein that is affected by a single amino acid mutation?
Hemoglobin – a mutation in the primary structure can cause sickle cell anemia.
What is the main function of DNA?
To store genetic information used to make proteins.
What is the function of RNA?
RNA acts as a copy of DNA's instructions and is used to synthesize proteins.
What are the three components of a nucleotide?
A sugar (pentose), a phosphate group, and a nitrogenous base.
What are the nitrogenous bases in DNA and RNA?
DNA: Adenine, Thymine, Cytosine, Guanine. RNA: Adenine, Uracil, Cytosine, Guanine.
What type of bond holds the sugar-phosphate backbone together in nucleic acids?
Phosphodiester bonds.
What are the two types of sugars in nucleotides, and where are they found?
Deoxyribose (in DNA) and Ribose (in RNA), in the nucleus
What does the term "double helix" refer to in DNA?
The structure of DNA consisting of two strands twisted together.
What is the relationship between DNA base pairs?
Adenine pairs with Thymine (A-T) with 2 hydrogen bonds, and Cytosine pairs with Guanine (C-G) with 3 hydrogen bonds.
What is ATP, and why is it important?
A nucleotide that stores energy for cellular processes.
What are the three domains of life?
Bacteria, Archaea, and Eukarya.
What is the composition of the bacterial cell wall?
Peptidoglycan, made of peptides (proteins) and glycans (sugars).
What is a plasmid?
A small, circular piece of DNA in bacteria that can be exchanged between cells.
How do phospholipids organize themselves in cell membranes?
They form a bilayer, with hydrophilic heads facing outwards and hydrophobic tails facing inwards.
What functional group(s) are found in proteins?
Carboxyl group, Amino group, and sometimes Sulfhydryl group.
What functional group(s) is found in nucleic acids?
Phosphate group.
What functional group(s) are associated with carbohydrates?
Hydroxyl group.
What functional group(s) is found in lipids?
Carbonyl group (Aldehyde or Ketone).
What is a monomer?
A single subunit that forms larger polymers in macromolecules.
What process assembles monomers into polymers?
Dehydration synthesis, which removes water to form a bond.
What process breaks down polymers?
Hydrolysis, which adds water to break bonds.
What is the monomer of carbohydrates?
Monosaccharide.
What is the molecular formula for glucose?
a 1:2:1 ratio of Carbon, Hydrogen, and Oxygen
What are disaccharides and give two examples?
Two monosaccharides joined together, e.g., Lactose (glucose + galactose) and Sucrose (glucose + fructose)
What bond forms between monosaccharides in carbohydrates?
Glycosidic bond.
What are polysaccharides and their function?
Long chains of monosaccharides used for energy storage (Starch in plants, Glycogen in animals) and structure (Cellulose in plants, Chitin in animals).
What element(s) are present in lipids?
Carbon, Hydrogen, and Oxygen (in lower ratios compared to carbohydrates).
What are the three types of lipids?
Triglycerides, Phospholipids, and Steroids.
What are saturated and unsaturated fatty acids?
Saturated fatty acids have no double bonds (straight chains), unsaturated fatty acids have double bonds (kinked chains).
What are phospholipids?
A lipid made of glycerol, two fatty acids, and a phosphate group. It forms the basic structure of cell membranes, with hydrophilic heads and hydrophobic tail
What are steroids, and give an example?
Steroids have four interlocking rings and are nonpolar. Examples include Cholesterol (structural), Estrogen, and Testosterone (steroids).
What makes phospholipids amphipathic?
They have both hydrophilic (polar) heads and hydrophobic (nonpolar) tails.
What are the building blocks (monomers) of proteins?
Amino acids.
What bond forms between amino acids in proteins?
Peptide bond (via dehydration synthesis).
What are the four levels of protein structure?
Primary (amino acid sequence), Secondary (alpha helices and beta sheets), Tertiary (3D folding of the entire chain), Quaternary (assembly of multiple chains.).
How do you know if a molecule needs partial charges?
If the molecule contains bonds between atoms with different electronegativities, creating polar covalent bonds
What is a polar covalent bond?
A bond where electrons are shared unequally between atoms due to a difference in electronegativity, creating partial charges.
What is the pH scale, and how is it measured?
The pH scale measures the concentration of hydrogen ions (H+) in a solution, ranging from 0 (most acidic) to 14 (most basic), with 7 being neutral.
What is the relationship between pH and hydrogen ion concentration?
The relationship is inverse. As pH decreases, the hydrogen ion concentration increases (acidic). As pH increases, the hydrogen ion concentration decreases (basic).
What is a buffer?
A substance that helps maintain a stable pH by absorbing or releasing hydrogen ions in response to changes in acidity or alkalinity.
How does a buffer work in acidic conditions?
In acidic conditions, a buffer releases a base (OH-) or absorbs hydrogen ions (H+) to reduce the acidity and maintain a neutral pH.
How does a buffer work in basic conditions?
The buffer releases hydrogen ions (H+) or absorbs hydroxide ions (OH-) to reduce alkalinity and maintain a neutral pH.
What are the two definitions of a base?
A base either releases hydroxide ions (OH-) in solution or absorbs hydrogen ions (H+), lowering the hydrogen ion concentration.
What are the key functional groups and their properties?
Methyl (nonpolar, hydrophobic, found in all macromolecules),
Hydroxyl (polar, hydrophilic, found in carbohydrates),
Carbonyl (Aldehyde and Ketone) (polar, hydrophilic, found in lipids),
Carboxyl (polar, hydrophilic, acts as an organic acid, found in proteins),
Amino (polar, hydrophilic, acts as an organic base, found in proteins),
Phosphate (polar, hydrophilic, found in nucleic acids),
Sulfhydryl (nonpolar, hydrophobic, found in proteins).
What is a carbon skeleton?
A carbon skeleton is a chain or ring of carbon atoms that forms the backbone of organic molecules, to which functional groups are attached.
What is the difference between a saturated and unsaturated hydrocarbon?
Saturated have single covalent bonds and are "full" of hydrogen, while unsaturated have double or triple bonds and fewer hydrogen atoms.
What happens to an atom's charge when it loses or gains electrons?
Losing electrons makes an atom positively charged (cation), and gaining electrons makes it negatively charged (anion).
What is the Law of Conservation of Energy?
Matter cannot be created or destroyed, only transformed.
What is a compound?
A substance made of two or more different elements in a fixed ratio, with unique properties emerging when the elements combine.
What is an ionic bond?
An ionic bond forms between oppositely charged ions, where one atom donates and another atom accepts electrons.
What is a covalent bond?
A covalent bond forms when atoms share pairs of electrons.
How do molecular formulas differ from structural formulas?
A molecular formula shows the types and numbers of atoms in a compound, while a structural formula shows the arrangement of atoms.
What are polar and nonpolar covalent bonds?
Polar covalent bonds occur when electrons are shared unequally between atoms, while nonpolar covalent bonds occur when electrons are shared equally.
What determines if a covalent bond is polar or nonpolar?
The difference in electronegativity between atoms. A difference greater than 1 typically results in a polar bond.
What is a hydrogen bond?
A weak bond between the partial positive charge of hydrogen in one polar molecule and the partial negative charge of another molecule.
What is surface tension?
The cohesive forces between water molecules due to hydrogen bonding, allowing small objects to float on water.
What is evaporative cooling?
The process by which sweat evaporates, breaking hydrogen bonds and releasing heat, cooling the body.
What is matter?
Matter is anything that takes up space, including objects you can see and feel, as well as gases like air.
What are elements?
The building blocks of matter that cannot be broken down into simpler substances by chemical reactions. They are listed in the Periodic Table.
What are atoms made of?
3 subatomic particles: protons (positive charge), neutrons (neutral charge), and electrons (negative charge).
What happens if you change the number of protons in an atom?
It changes the element, which is not allowed in normal chemical reactions (only in nuclear reactions).
What is the atomic number?
The atomic number is the number of protons in an atom, which defines the element.
What is the atomic mass?
The total number of protons and neutrons in an atom.
How do you find the number of neutrons in an atom?
Subtract the atomic number (protons) from the atomic mass to find the number of neutrons.
What is an isotope?
Atoms of the same element that have different numbers of neutrons, leading to different atomic masses.
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