Biology Exam 2

What is the structure of the fluid mosaic model?

It consists of a phospholipid bilayer embedded with diverse proteins.

What is diffusion?

Passive transport; down a concentration gradient, spreading out of particles on either side of a semi-permeable membrane until equilibrium is reached.

Define osmosis.

Diffusion of water, similar to diffusion in general.

What is active transport?

Moving against the concentration gradient; requires energy (ATP).

What is passive transport?

Moving down a concentration gradient; does not require energy (ATP).

What is facilitated diffusion?

Passive transport of polar or charged molecules using transport proteins.

Define endocytosis.

Transport of large molecules INTO the cell; plasma membrane engulfs and pinches off to bring substances into the cell via a vacuole/vesicle.

What is exocytosis?

Transport of large molecules OUT of the cell.

What is an exergonic reaction?

A reaction that releases energy; the potential energy of the reactants is larger than that of the products.

What is an endergonic reaction?

A reaction that requires input of energy; the potential energy of the products is larger than that of the reactants.

What is phosphorylation?

The addition of a phosphate group to a compound (like ADP to ATP).

What happens to a cell in a hypotonic solution?

The cell gains water; animal cells may lyse, while plant cells remain normal.

What happens to a cell in an isotonic solution?

There is no net water gain or loss; animal cells remain normal, while plant cells are flaccid.

What happens to a cell in a hypertonic solution?

The cell loses water; both animal and plant cells shrivel.

What are the functions of enzymes?

They speed up chemical reactions, lower activation energy, fit specific substrates, and are not used up in chemical reactions.

Where do competitive enzyme inhibitors bind?

They block the active site so the substrate cannot bind.

Where do noncompetitive enzyme inhibitors bind?

They bind elsewhere on the enzyme, causing a change in the shape of the active site.

What is carbon fixation?

The first step of the Calvin cycle, where carbon from carbon dioxide binds to RuBP, facilitated by RuBIsCO.

What is the Calvin cycle?

The light-independent reactions of photosynthesis, consisting of carbon fixation, reduction, release of G3P, and regeneration of RuBP.

What is ATP synthase?

An enzyme that catalyzes the phosphorylation of ADP to ATP in both photosynthesis and cellular respiration.

What is the role of oxygen in aerobic cellular respiration?

It is the final electron acceptor of oxidative phosphorylation.

What is the purpose of the electron transport chain?

A series of redox reactions that produce a H+ gradient, driving the phosphorylation of ADP to ATP.

What is glycolysis?

The first part of cellular respiration, occurring in the cytosol, which breaks down glucose into 2 pyruvates.

What are the steps of the Calvin cycle?

1. Carbon fixation 2. Reduction 3. Release of one molecule of G3P 4. Regeneration of RuBP; products are glucose, NADP+, and ADP.

What is the chemical equation for photosynthesis?

6CO2 + 6H2O + light energy → C6H12O6 + 6O2; an endergonic reaction where carbon is reduced.

What is the chemical equation for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + heat; an exergonic reaction where carbon is oxidized.