Biol 311 Anabolism, Biosynthesis, Peptidoglycan

________ pathways must operate ________ in the direction of biosynthesis

anabolic, irreversibly

anabolic and catabolic reactions are...?
a) coupled
b) physically separated

b) physically separated

allows pathways to operate simultaneously but independently

______ produces NADH
NADPH is used as an electron donor for _________

catabolism, anabolism

large assemblies (ex. ribosomes) form spontaneously from macromolecules by __________

self-assembly

____________ are used as starting substrates for biosynthetic pathways. most are used for the biosynthesis of amino acids.

carbon skeletons

metabolism

used to describe all of the chemical reactions inside a cell

how many enzymes are unique to gluconeogenesis, and how many are shared with glycolysis?

4, 7

in gram (+/-)? cell walls there is a pentapeptide connected to the tetrapeptides

gram positive

list the main differences between gram-positive and gram-negative bacterial cell walls

gram-negative: inner and outer membrane, lipopolysaccharide (LPS), periplasmic space and thin peptidoglycan between the two membranes
gram-positive: teichoic acid, thick peptidoglycan

peptidoglycan has (4 or 5) amino acids?

4
(it starts off as 5 and then becomes 4)

what is attached to lipid 1, and what attaches it there?

NAM and pentapeptide (and lipid zero/bactoprenol) are attached to lipid 1.

UDP attaches them.

what is attached to lipid 2?

NAG, NAM, pentapeptide, bactoprenol

what happens to lipid 2 after it has the two sugars attached to it (NAM and NAG)?

it is flipped across the membrane by the flippase enzyme. it started in the cytoplasm and is now in the periplasmic space.

What is transpeptidation?

peptide cross-links between peptidoglycan chains are formed

what happens after transpeptidation?

The bactoprenol donor moves back across the membrane and loses one phosphate. It is now bactoprenol phosphate and can begin a new cycle.

In an isotonic solution, the cell...?
a) explodes, or lyses
b) shrinks
c) loses its shape a little, but is still okay

c

In a hypertonic solution, the cell...?
a) explodes, or lyses
b) shrinks
c) loses its shape a little, but is still okay

b

In a hypotonic solution, the cell...?
a) explodes, or lyses
b) shrinks
c) loses its shape a little, but is still okay

a

What does bacitracin do?

Bacitracin interferes with the metabolism of the membrane - it messes with the recycling of the bactoprenol.

What does penicillin do?

Penicillin interferes with the transpeptidation reaction. It is an inactivator that binds covalently to the enzyme, making it ineffective. The osmotic pressure kills the cell because the wall becomes loose.

Describe how transpeptidation works.

There is a nucleophilic attack from DAP into the 4th amino acid, D-alanine.
D-ala is clipped, and a new peptide bridge is formed.
This makes the cell wall rigid.

linear polymer is formed by ________

transglycosylation

Most macromolecules are derived from ______

the TCA cycle

Catabolic and anabolic pathways are ________, as some enzymes function ________.
a) very similar, in the same way
b) not identical, in only one direction

b) Catabolic and anabolic pathways are not identical, as some enzymes function in only one direction.

*note that there are enzymes that are used for both catabolic and anabolic processes to save materials and energy