AP Biology Unit 3 - Cellular Energetics Flashcards

Flashcards based on lecture notes about cellular energetics, enzyme function, photosynthesis, and cellular respiration.

Enzyme

Protein catalyst; speeds up a reaction without being consumed.

Polypeptide

Chain of amino acids joined and connected by peptide bonds.

Protein

Biological molecule made of one or more polypeptides.

Amino acid

Polypeptide monomers.

Peptide bond

Covalent bond between the carboxyl group on one amino acid and the amino group on another.

Primary structure

The level of protein structure referring to the specific sequence of amino acids.

Secondary structure

The localized folding of the polypeptide backbone of a protein due to hydrogen bond formation between constituents of the backbone.

Alpha helix

A spiral shape in the secondary structure of a protein.

Beta pleated sheet

Chain folded back and forth in the secondary structure of a protein.

Tertiary structure

Protein folding a result of interactions between side chains.

Quaternary structure

Shape of an overall protein that is formed by the conjoining of multiple polypeptides.

Denaturation

Occurs when protein unravels and loses shape; protein becomes inactive or dysfunctional.

Chaperonin

A protein molecule that assists in the proper folding of other proteins.

Active site

The specific region of an enzyme that attaches to the substrate.

Enzyme substrate

The reactant that an enzyme acts on.

Induced-fit model

Theory where an enzyme and a substrate bind together, making the active site change shape to favor the substrate, thereby allowing the reaction to proceed faster.

Cofactors

Minerals that assist in enzyme function.

Coenzymes

Vitamins that assist in enzyme function.

Allosteric enzymes

Help in the regulation of enzyme activity by having allosteric sites that when activated by a certain substrate, inhibit enzyme function.

Feedback inhibition

Process of enzyme activity control where the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

Competitive inhibition

When a non-reactant molecule competes with a substrate for access to the active site, thus inhibiting enzyme activity.

Noncompetitive inhibition

When a non-reactant molecule is produced somehow and attaches to an enzyme’s allosteric site, thereby changing the enzyme’s shape and inhibiting enzyme activity.

Adenosine triphosphate (ATP)

Important energy molecule for multiple reactions.

Heterotroph

Organism that obtains energy from sources outside of itself.

Autotroph

Organism produces its own energy by converting solar energy into chemical energy.

Photosynthesis

Process by which producers use light energy to create their own chemical energy from carbon and water.

Pigment

Molecule that works to absorb light; important in photosynthesis.

Chlorophyll

Important pigment in photosynthesis.

Thylakoid

Sac-like photosynthetic membrane found in chloroplasts.

Stroma

Region outside the thylakoid membranes in chloroplasts.

NADP+

One of the carrier molecules a transfer to high-energy electrons from chlorophyll to other molecules.

Light dependent reactions

Reactions of photosynthesis that use light energy.

Light independent reactions

Photosynthetic reactions that do not require light energy to proceed.

Cellular respiration

Opposite process of photosynthesis; works to release energy by breaking down glucose in the presence of O2.

Calvin Cycle

Cycle in plants that makes sugar from carbon dioxide, H+ ions, and high-energy electrons carried by NADPH.

Stomata

Pores in a leaf; allow for the entrance of CO2 and the exit of O2.

Photosystem

Cluster of chlorophyll and other molecules in a thylakoid.

Electron transport chain

A series of electron carrier proteins that shuttle high-energy electrons during ATP-generating reactions.

ATP synthase

Proteins located in the thylakoid membrane that allow H+ ions to pass through it.

Mesophyll

Inner tissue of a leaf, contain many chloroplasts.

Grana

Thylakoid stacks.

Guard cells

Responsible for opening and closing stomata.

NADP+

An electron acceptor that is reduced and is used to fuel the Calvin cycle.

p700

Chlorophyll located in photosystem I.

p680

Chlorophyll located in photosystem II.

Photorespiration

Process where o2 gets substituted for CO2 in the calvin cycle