AP Biology Study Guide

Why is water considered polar?

Water is polar because oxygen is more electronegative than hydrogen, creating partial positive and negative charges.

What are hydrogen bonds?

Hydrogen bonds are weak interactions between a hydrogen atom and an electronegative atom, but they can be powerful collectively.

What is cohesion in water?

Cohesion explains water sticking to itself, enabling processes like transpiration.

What is adhesion in relation to water?

Adhesion explains water sticking to other polar surfaces.

What is surface tension in water?

Surface tension results from hydrogen bonding at the surface layer of water.

What is high specific heat?

High specific heat allows water to stabilize temperatures in organisms and ecosystems.

What does high heat of vaporization do in biology?

High heat of vaporization allows evaporative cooling through processes like sweating and transpiration.

How does the structure of water relate to its biological functions?

Connecting the structure of water to hydrogen bonding and biological functions helps understand various biological processes.

What role does carbon play in biological molecules?

Carbon forms four covalent bonds, allowing for molecular diversity through chains, branches, and rings.

What is nitrogen's role in biological molecules?

Nitrogen is required for amino acids and nucleotides; its limitation restricts protein and DNA synthesis.

What is phosphorus essential for?

Phosphorus is essential for ATP, nucleic acids, and phospholipid membranes.

What is sulfur's role in proteins?

Sulfur forms disulfide bonds that stabilize protein structure.

What determines the reactivity of biological molecules?

Functional groups determine the polarity, acidity, and reactivity of biological molecules.

What is dehydration synthesis?

Dehydration synthesis is a reaction that removes water to form covalent bonds between monomers.

What is hydrolysis?

Hydrolysis is a reaction that adds water to break covalent bonds in a polymer.

How do lipids differ from other macromolecules?

Lipids are not true polymers in the repeating monomer-chain sense like proteins, nucleic acids, and carbohydrates.

What is the importance of monomer sequence in macromolecules?

A change in monomer sequence can alter macromolecule structure and, consequently, its function.

What are monosaccharides and polysaccharides?

Monosaccharides are carbohydrate monomers, while polysaccharides are polymers formed by covalent glycosidic bonds.

What is the significance of branching in carbohydrates?

Branching increases the number of available ends, allowing faster enzyme access and quicker glucose release.

How do starch, glycogen, and cellulose differ?

Starch stores energy in plants, glycogen in animals, and cellulose provides structural support in plant cell walls.

What do cellulose and starch have in common?

Both cellulose and starch are made of glucose, but differences in bonding orientation lead to different functions.

What is the relationship between structure and function in biology?

The structure of a molecule determines its function, which is a central idea in biology.

What are the characteristics of saturated and unsaturated fatty acids?

Saturated fatty acids have only single bonds, while unsaturated fatty acids have at least one double bond that causes kinks.

What is the effect of double bonds on membrane fluidity?

More double bonds increase membrane fluidity and lower melting points of lipids.

What are the roles of phospholipids in membranes?

Phospholipids are amphipathic and spontaneously form bilayers in aqueous environments, crucial for membrane structure.

How does cholesterol affect cell membranes?

Cholesterol stabilizes cell membranes and helps regulate their fluidity.

How do DNA and RNA differ?

DNA uses deoxyribose and thymine, while RNA uses ribose and uracil; also DNA strands are antiparallel.

What is the consequence of a single amino acid substitution in a protein?

A single amino acid substitution can alter protein folding and its function.

What happens during denaturation?

Denaturation disrupts secondary, tertiary, and quaternary structures without breaking peptide bonds.

What is the primary structure of proteins?

The primary structure is the sequence of amino acids that determines all higher levels of protein structure.

What is the function of ribosomes?

Ribosomes are involved in protein synthesis and are present in all cells, linking structure to common ancestry.

What is the role of the rough ER, Golgi, and vesicles in protein processing?

The rough ER, Golgi, and vesicles together function as the pathway for protein processing and shipping.

How does cell size relate to surface area to volume ratio?

As cell size increases, volume grows faster than surface area, resulting in decreased surface area to volume ratio.

What is the significance of a high surface area to volume ratio?

A high surface area to volume ratio allows for more efficient exchange of nutrients, wastes, gases, and heat.

How does the phospholipid bilayer form?

The phospholipid bilayer forms due to phospholipids being amphipathic, with hydrophilic heads outward and hydrophobic tails inward.

What factors influence membrane permeability?

Membrane permeability is influenced by the hydrophobic fatty acid tails and the size and polarity of molecules trying to cross.

What is osmosis?

Osmosis is the movement of water from areas of low solute concentration to areas of high solute concentration.

What occurs during active transport?

Active transport moves substances against their concentration gradient and requires ATP.

What is the function of the Na⁺/K⁺ pump?

The Na⁺/K⁺ pump moves 3 Na⁺ out and 2 K⁺ in per ATP, maintaining essential ion gradients.

What is the significance of compartmentalization in cells?

Compartmentalization allows for specialized processes to occur in distinct membrane-bound organelles.

What is the importance of checkpoints in the cell cycle?

Checkpoints regulate the cell cycle, ensuring proper division and preventing cancerous growth.

How does meiosis contribute to genetic diversity?

Meiosis creates genetic diversity through independent assortment and crossing over.

What distinguishes prokaryotic and eukaryotic cells?

Prokaryotic cells lack membrane-bound organelles, while eukaryotic cells contain them.

How do environmental changes affect phenotype?

Environmental changes can affect gene expression, leading to variations in phenotype without altering the DNA sequence.

What is the relationship between genotype and phenotype?

Phenotype is determined by both the genotype and the environmental influences on that genotype.

What evidence supports the theory of evolution?

Evidence for evolution includes homologous structures, vestigial organs, and molecular similarities across species.

What is natural selection?

Natural selection is the process where organisms with beneficial traits survive and reproduce, leading to evolutionary change.