Bacterial Metabolism: Anabolism

Question 1

What are carbohydrates synthesized from?
Bonus: Give 2 examples

Answer 1

from activated forms of glucose
1. UDPG (uridine diphosphoglucose)
1. ADPG (adenosine diphosphoglucose)

Question 2

precursor of many glucose derivatives used in synthesizing:
1. peptidoglycan component (N-acetylglucosamine and N-acetylmuramic acid)
1. lipopolysaccharide component of outer membrane of G- bacteria

Answer 2

uridine diphosphoglucose (UDPG)

Question 3

Explain

Gluconeogenesis

Answer 3

Oxaloacetate → Phosphoenolpyruvate → Glucose
* For when glucose is not used as carbon source (chemolithotrophs)
* Glucose is synthesized from PEP (Phosphoenolpyruvate)
* No PEP = Oxaloacetate synthesizes PEP

Question 4

Define

Amino Acid (AA)

Answer 4

monomer of polypeptides/proteins

Question 5

T/F

None of the 20+ amino acids (AA) in bacteria come from nutrient sources

Answer 5

F
Some can obtain from nutrient sources, but not all

Question 6

Explain

How is the amino group in AA derived?

Answer 6

From an inorganic nitrogen source (ex. ammonia)

• AAs glutamate/glutamine are synthesized via glutamate dehydrogenase/glutamine synthetase
• Ammonia is incorporated
• Ammonia can be transferred to form other nitrogenous compounds (including other amino acids)

Question 7

T/F

Carbon skeletons used to synthesize AA are intermediates of glycolysis & citric acid cycle

Answer 7

T

Question 8

Define

Nucleotides

Answer 8

building blocks of nucleic acids

Question 9

3 major components of nucleotides

Answer 9

1. Nitrogenous base
   Purines (Adenine / Guanine)
   Pyrimidines (Thymine, Cytosine, Uracil)
2. 5-carbon sugar backbone
   Ribose in RNA
   Deoxyribose in DNA
3. Triphosphate group

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Question 10

Explain

Purine synthesis

Answer 10

Inosinic acid + ribose
AAs + CO2 + vitamins are phosphorylated → inosinic acid

Question 11

Explain

Pyrimidine synthesis

Answer 11

Uridylate + riboxe
AAs + CO2 → backbone (orotic acid) → orotic acid is phosphorylated → uridylate

Question 12

Identify

Enzyme that changes ribose → deoxyribose (for DNA)

Answer 12

Ribonucleotide reductase

Question 13

What does the Pentose Phosphate Pathway (PPP) produce?
How?

Answer 13

pentose sugar is produced, through oxidizing glucose

Question 14

List

4 products of Pentose Phosphate Pathway

Answer 14

1. pentose sugar
2. CO2
3. NADPH
4. ribulose-5-phosphate

Question 15

How is CO2 produced in the Pentose Phosphate Pathway?

Answer 15

• Glucose has 6 C’s, so 1 C atom should be removed
• Remove 1 C → formation of 1 CO2

Question 16

How is NADPH produced in the Pentose Phosphate Pathway?

Answer 16

• Reduced form of NADH
• Used by ribonucleotide reductase to convert ribonucleotides to deoxyribonucleotides
• Also forms fatty acids, but more relevant for DNA

Question 17

What is the use of ribulose-5-phosphate?

Answer 17

Starting material for ribonucleotide generation & gluconeogenesis

Question 18

How are fatty acids & lipids related?

Answer 18

Fatty acids are the backbone of lipids

Question 19

How are fatty acids & lipids related?

Answer 19

Fatty acids are the backbone of lipids

Question 20

Explain

Fatty Acid biosynthesis

Answer 20

• Uses ACP (acyl carrier protein)
• Holds a growing fatty acid chain (while 2 C’s from malonate are added to it)
• Malonate has 3 carbons: 2 goes to fatty acid chain, 1 becomes CO2
• When fatty acid chain is formed, ACP releases it
• Ex. 16 carbons in chain = 8 malonate compounds used

Question 21

Differentiate

FA membrane in bacterial species w/ cold temp vs bacterial species w/ high temp

Answer 21

Cold/Low temp
* More fluid
* Shorter & more unsaturated FAs
* So that FAs don’t overlap/compact → become immobile

Hot/High temp
* More rigid
* Longer & more saturated FAs
* To restrict mobility of phospholipids & proteins on their membranes

Question 22

Differentiate

Lipid biosynthesis
Fats (triacylglycerides) biosynthesis

Answer 22

Lipid biosynthesis: FA + 1 molecule of glycerol via ester linkage

Fats (triacylglycerides): FA + 3 glycerol via ester linkage

Question 23

Fill in the blank

Glycerol may have ____ additions

Answer 23

polar group

Question 23

Fill in the blank

Glycerol may have ____ additions

Answer 23

polar group

Question 24

Why do the additions to glycerol have to be polar?

Answer 24

so that one end of phospholipid is hydrophilic

Question 25

Fill in the blank

In archaea, membrane lipids with phytanyl and biphytanyl side chains are made from ____ and use an ___ linkage

Answer 25

isoprene, ether linkage