Bio Unit 2 Cellular Respiration

Flashcards review key concepts about energy and cellular respiration, focusing on metabolism, cellular pathways, and thermodynamics.

What is metabolism?

The sum of all biochemical reactions occurring in a cell.

What are the two main types of metabolic reactions?

Catabolism (breaking down molecules) and anabolism (building up molecules).

Define glycolysis.

The metabolic pathway that breaks down glucose into two pyruvate molecules, producing ATP and NADH.

What is the role of NADH and FADH2 in cellular respiration?

They carry electrons to the electron transport chain, where they are oxidized in complexes that use their reduction energy to move protons from the matrix to the intermembrane space, creating an electrochemical gradient that allows ATP synthase to function.

What is the process of oxidative phosphorylation?

The use of a hydrogen ion gradient generated by the electron transport chain to produce ATP via ATP synthase in chemiosmosis.

What are the products of the Krebs cycle for each acetyl-CoA?

2 CO2, 1 ATP, 3 NADH, and 1 FADH2.

Explain the difference between aerobic and anaerobic respiration.

Aerobic respiration requires oxygen and produces more ATP, while anaerobic respiration occurs without oxygen through fermentation and yields less ATP.

What happens during lactate fermentation?

Pyruvate is converted into lactate using the reduction energy of NADH, forming NAD+, which allows glycolysis to continue.

What is substrate-level phosphorylation?

A method of ATP production where a phosphate group is directly transferred to ADP from a substrate.

Define endergonic and exergonic reactions.

Endergonic reactions require energy input and have a positive ΔG, while exergonic reactions release energy and have a negative ΔG.

What is the main purpose of the electron transport chain?

To transfer electrons from electron carriers (NADH and FADH2) and generate a hydrogen ion gradient for ATP synthesis.

What is the role of Coenzyme A in metabolism?

carrying acetyl groups into the Krebs cycle to form citrate once added to oxaloacetate

How does ATP synthase work?

It utilizes the flow of H+ ions down their gradient to synthesize ATP from ADP and inorganic phosphate. Rotates like a turbine with H+ being the water

What is the significance of the free energy change (ΔG) in biochemical reactions?

indicates whether a reaction will occur spontaneously; negative values suggest it can proceed without external energy while a positive shows that it requires an input of energy to take place.

Why do organisms need constant energy input?

To fulfil the activation energies of essential life reactions

How does feedback inhibition function in metabolic pathways?

It regulates enzyme activity based on product levels which inhibit certain enzymes that produce them through allosteric inhibition, preventing the overproduction of metabolites.

What is the relationship between metabolic pathways and energy?

Metabolic pathways transform energy stored in food into usable forms for cellular processes.

What are the two types of fermentation?

Lactate and Ethanol

Fermentation does not produce ATP, why is it essential regardless?

Because in the absence of O2 for the electron transport chain it re-oxidizes NADH to allow for glycolysis to continue using NAD+ and prevents NADH build up in the cell

What is pyruvate oxidation?

intermediate reaction between glycolysis and the krebs cycle where pyruvate is converted into acetyl-CoA

Decarboxylation

The breaking apart of a carbon from a molecule to form the waste product CO2

What are the products of pyruvate oxidation per pyruvate?

1 acetyl-CoA,1 NADH, and 1 CO2

What is the Krebs cycle?

a series of chemical reactions that breaks the carbons of acetyl from citrate one by one through carboxylation, producing 1 ADP, 3 NADH and 1 FADH2

What are the products of the Krebs cycle per glucose?

6 NADH, 2 FADH2, 2ATP, 4CO2

How many times does the Krebs cycle turn for each glucose molecule?

2

What is the electron transport chain?

a series of protein complexes in the inner mitochondrial membrane that transfer electrons and pump protons to generate ATP.

What is the main function of the electron transport chain?

to create a proton gradient across the inner mitochondrial membrane, which drives ATP synthesis.

What is the final electron acceptor in the electron transport chain?

oxygen

What is oxidative phosphorylation?

the production of ATP using the electron transport chain and chemiosmosis