AP Biology Unit 3 Vocab

Acetaldehyde

a colorless, volatile organic compound with the chemical formula CH3CHO, considered an aldehyde, which is produced naturally by the body during the metabolism of ethanol (alcohol) by the liver enzyme alcohol dehydrogenase

Acetyl CoA

a molecule that plays a central role in many biochemical reactions that metabolize proteins, carbohydrates, and lipids

Aerobic respiration

the process by which cells generate energy (ATP) by breaking down glucose molecules in the presence of oxygen, producing carbon dioxide and water as byproducts

Alchohol fermentation

an anaerobic process where yeast converts sugars like glucose into ethanol (alcohol) and carbon dioxide as byproducts, essentially breaking down sugar without oxygen present

ATP Synthase

an enzyme embedded in cellular membranes that utilizes the energy from a proton gradient to synthesize adenosine triphosphate (ATP)

Enzymes

a protein molecule that acts as a biological catalyst, significantly speeding up the rate of a specific chemical reaction within a living organism without being consumed in the process

Photosynthesis

is the biological process by which green plants, algae, and some bacteria convert light energy from the sun into chemical energy stored in the form of glucose (a sugar). This process primarily occurs in the chloroplasts of plant cells and involves the pigment chlorophyll, which captures sunlight.

Cellular Respiration

is a biological process in which cells convert glucose and other organic molecules into energy in the form of adenosine triphosphate (ATP). This process occurs in both plants and animals and provides the energy required for various cellular activities.

C3 Pathway

The C3 pathway, also known as the Calvin cycle, is the primary photosynthetic pathway used by most plants to fix carbon dioxide (CO₂) from the atmosphere and synthesize organic compounds. It is called the C3 pathway because the first stable product formed in the cycle is a three-carbon compound called 3-phosphoglycerate (3-PGA). This process occurs in the stroma of chloroplasts.

C4 Pathyway

The C4 pathway is a carbon fixation process used by certain plants to efficiently capture carbon dioxide for photosynthesis in hot and dry environments. This pathway helps plants minimize photorespiration and water loss, making them well-suited for arid conditions.

Calvin Cycle

A series of chemical reactions that occurs as part of the dark reactions of photosynthesis, in which carbon is broken away from gaseous carbon dioxide and fixed as organic carbon in compounds that are ultimately used to make sugars and starch as food.

Catalyze

to speed up a chemical or biochemical reaction by using a catalyst.

Chlorophyll

A green pigment found in plants that absorbs light energy necessary for photosynthesis.

Coenzyme A

A molecule that assists enzymes in biochemical reactions, often involved in the metabolism of fatty acids and the synthesis of acetyl-CoA.

Cytoplasm

the gel-like fluid that fills the inside of a cell, excluding the nucleus, and is made up of water, salts, and organic molecules

Electron Transport Chain

A series of protein complexes and other molecules that transfer electrons through a membrane within mitochondria or chloroplasts, driving the production of ATP.

Ethanol

A type of alcohol produced by fermentation, commonly used in beverages and as a fuel. In CR, it can be generated from glucose in anaerobic conditions.

FAD

A coenzyme involved in redox reactions, important for cellular Respiration and the Krebs cycle.

FADH2

A reduced coenzyme that carries electrons to the ETC, produced during the Krebs Cycle.

G3P

A three-carbon sugar produced in the Calvin cycle, serving as a key intermediate in the synthesis of glucose and other carbohydrates.

Glucose

A simple sugar that is an important energy source in living organisms and a component of many carbohydrates.

Glycolosis

The metabolic pathway that converts glucose into pyruvate, producing ATP and NADH in the process.

Grana

Stacks of thylakoids within chloroplasts, where the light-dependent reactions of photosynthesis occur.

Inter-membrane space

The region between the inner and outer membranes of mitochondria, where protons accumulate during electron transport.

Latic Acid Fermentation

A metabolic process by which glucose is converted into energy and lactic acid in the absence of oxygen, commonly occurring in muscle cells during intense exercise.

Light dependent reactions

The first stage of photosynthesis that occurs in the thylakoid membranes, converting light energy into chemical energy in the form of ATP and NADPH.

Malate

A four-carbon intermediate in the Krebs cycle formed from oxaloacetate and acetyl-CoA.

Matrix

The innermost compartment of mitochondria where the Krebs cycle occurs, containing enzymes and substrates necessary for cellular respiration.

Mitochondria

Organelles that produce ATP through cellular respiration, containing their own DNA and double membrane.

NAD+

A coenzyme that acts as an electron carrier in cellular respiration, playing a crucial role in redox reactions.

NADH

The reduced form of NAD+, it carries electrons to the electron transport chain for ATP production.

NADPH+

A coenzyme that carries electrons and reduces agents in photosynthesis, generated in the light reactions.

NADPH

A coenzyme that acts as a reducing agent in biochemical reactions, providing electrons and protons for anabolic processes such as photosynthesis.

Oxaloacetate

A four-carbon molecule that plays a key role in the Krebs cycle, combining with acetyl-CoA to form citrate.

Oxidative Phosphorylation

The process by which ATP is produced in the mitochondria through the transfer of electrons from NADH and FADH2 to oxygen, coupled with the movement of protons across the inner mitochondrial membrane.

PEP carboxylase

An enzyme that catalyzes the addition of carbon dioxide to phosphoenolpyruvate (PEP) to form oxaloacetate in the process of carbon fixation.

Photosystem 1

A protein complex in the thylakoid membrane that absorbs light energy, facilitating the conversion of solar energy into chemical energy during photosynthesis.

Photosystem 2

A protein complex involved in the light-dependent reactions of photosynthesis, responsible for capturing light energy and transferring electrons to the electron transport chain.

Product

A molecule produced as a result of a biochemical reaction, often serving as a substrate for subsequent reactions in metabolic pathways.

Pyruvate

A three-carbon molecule produced during glycolysis, pyruvate is a key intermediate in cellular respiration and fermentation.

Pyruvate oxidation

is the process by which pyruvate is converted into acetyl-CoA, producing NADH and releasing carbon dioxide before entering the Krebs cycle.

Rubisco

An enzyme that catalyzes the first step of the Calvin cycle by fixing carbon dioxide to ribulose bisphosphate.

RuBP

A five-carbon molecule that reacts with carbon dioxide during the Calvin cycle, ultimately leading to the production of glucose.

Stroma

The fluid-filled space surrounding the thylakoids in chloroplasts where the Calvin cycle occurs.

Substrate

The reactant molecule that an enzyme binds to and acts upon in a biochemical reaction.

Substrate level phosphorylation

A process of ATP generation that occurs when a phosphate group is directly transferred from a substrate to ADP, producing ATP. This occurs during glycolysis and the Krebs cycle.

Thylakoid

A membrane-bound compartment inside chloroplasts where the light-dependent reactions of photosynthesis occur.

Uncoupling of oxidative phosphorylation

The process where the proton gradient generated during electron transport is dissipated, leading to reduced ATP production while still allowing electron transport to occur.