Chapter 12

Question 1

What are the principles governing biosynthesis?

Answer 1

Large Molecules are made from small molecules

Many enzymes do duty duty, however, some enzymes function in only one direction

Anabolism consumes energy

Catabolism and anabolism can be physically separated

Catabolism and anabolism often use different cofactors

After macromolecules have been constructed from simpler precursors, they are assembled into larger, more complex structures such as supramolecular systems and organelles by a process called self-assembly.

Question 2

Precursor metabolites

Answer 2

Critical to anabolism because they give rise to all other molecules made by the cell

They are the carbon skeletons used as starting points for the synthesis of monomers and other building blocks needed to make macromolecules.

Question 3

Central metabolic pathways

Answer 3

Aoo precursor metabolites are intermediates of the glycolytic pathways. They play a central role in metabolism.

Question 4

Autotrophs use ________ as their sole principal carbon source

Answer 4

CO₂

Question 5

Calvin-Benson Cycle (also known as the Calvin Cycle)

Answer 5

The main pathway for the fixation (reduction and incorporation) of CO₂ into the organic material by photoautotrophs and chemolithoautotrophs.

Question 6

The Calvin-Benson Cycle is divided into 3 phases.

Answer 6

Carboxylation Phase

Reduction Phase

Regeneration Phase

Question 7

What happens in the carboxylation phase of the Calvin Cycle?

Answer 7

CO₂ is added to the 5-carbon Ribuloase 1,5-biphosphate (RuBP) to create a 6-carbon chain which is then split into two 3-carbon molecules called phosphoglycerate (PGA)

Question 8

What happens in the reduction phase of the Calvin Cycle?

Answer 8

the PGA is reduced to Glyceraldehyde 3-Phosphate using the enzyme NADPH

Question 9

What happens in the regeneration phase of the Calvin Cycle?

Answer 9

The RuBP is reformed so that the cycle can repeat. (reverse of the pentose phosphate pathways)