AGRC2001 Agricultural Biochemistry Exam Flashcards

Flashcards from Agricultural Biochemistry lecture notes.

Why is carbon considered the molecule of life?

Versatility, it can form 4 covalent bonds

Why do the 20 different amino acids have different properties in terms of hydrophobicity, charge and aromaticity?

Structural variation in the R side chain

Why do living systems not decompose in line with an isolated view of the Second Law of Thermodynamics?

They are open systems coupled to an external source of energy, for example light and food

In comparing aerobic and anaerobic metabolism in animals, what is a key difference in ATP production?

Aerobic metabolism produces more total ATP but at a slower rate

What effect does an enzyme have on the equilibrium constant and the rate at which equilibrium is reached?

Does not change the position of the equilibrium constant but increases the rate at which equilibrium is reached

What are the main biochemical outputs of glycolysis?

ATP, NADH and pyruvate

What defines the rate-limiting step in a biochemical pathway?

It is the slowest step in the sequence

Why do living systems turn feed energy into ATP?

All of the above.

Which of these biochemical processes would you expect to liberate the most ATP?

Electron transport chain activity

What is the function of the ATP synthase molecular motor?

Phosphorylates ADP

What bioenergetic molecules are mammalian cells provided with via the circulation?

Glucose, free fatty acids and glycerol, and amino acids

How is gluconeogenesis kept functionally separate from glycolysis?

The two pathways involve only some of the same enzymes, with further separation created by organelles and cell compartments, tissue specificity and reciprocal regulation.

During aerobic respiration, what is the sequence of mitochondrial processes?

The TCA cycle spins, the electron transport chain is activated, a proton gradient is produced across the inner mitochondrial membrane, a downhill flow of protons back into the matrix drives the rotor of the ATP synthase that phosphorylates ADP.

When a lactating mammal makes milk fat, what ingredients are required?

Carbon skeletons provided by Acetyl CoA, reducing power from NADPH and ATP for bioenergetic coupling

Where did Usain Bolt's muscles derive their fuel for contraction during the 100 metres sprint, expressed in the order they were burned?

ATP stored in the muscle first, then muscle phosphocreatine, then muscle glycogen granules.

What is the rate limiting step in a biochemical pathway?

It is the slowest step in the sequence