quiz 5- week 5/6

Question 1

Where do bacteria get energy for metabolic reactions?

Answer 1

Light – Phototrophs
Chemicals – Chemotrophs

Question 2

Where do bacteria get carbon?

Answer 2

Organic compounds – Heterotrophs
CO2 – Autotrophs

Question 3

Do bacteria use oxygen as a final electron acceptor?

Answer 3

Yes – Aerobe (cellular respiration, ETC)
No – Fermentation or other anaerobic respiration

Question 4

How is energy stored in ATP?

Answer 4

Phosphodiester bond stores energy
ATP structure: Adenosine – phosphate-phosphate-phosphate
Repulsion of negative charges stores energy

Question 5

What happens when there’s low ATP in the cell?

Answer 5

ADP converts to AMP

Question 6

What are the reduced forms of NAD+, NADP+, and FADH+?

Answer 6

NADH, NADPH, FADH2
These reduced forms bring electrons to the Electron Transport Chain

Question 7

How does differential charge across a membrane store energy?

Answer 7

It allows ions to be easily transported down their charge/concentration gradient

Question 8

How does human digestion deal with different polysaccharides?

Answer 8

Starches are easily digested
Insoluble fiber cannot be digested
Human microbiome helps digest undigestible materials

Question 9

How do bacteria contribute to food spoilage?

Answer 9

Hydrolyze lipids to glycerol and fatty acids – can undergo fermentation or respiration (TCA cycle)
Use proteases to cleave amino acids for TCA cycle

Question 10

What is the difference between catabolism and anabolism?

Answer 10

Catabolism: Breaking down larger components into smaller parts
Anabolism: Building larger components from smaller parts

Question 11

What role does the gut microbiome play in metabolism?

Answer 11

Symbiotic relationship enhances ability to catabolize many molecules
Poor microbiome health correlates with poor mental and physical health

Question 12

What happens in glucose catabolism?

Answer 12

Glucose → 2 pyruvates (via EMP, ED, or PPP pathways):
-EMP (Glycolysis): Generates 4 ATP, 2 NADH
-ED: Generates 2 ATP, 1 NADH, 1 NADPH
-PPP: Generates 2 NADPH, 1 ATP

Question 13

What are the two pathways after pyruvates are generated in glucose catabolism?

Answer 13

Fermentation: Produces various products depending on bacteria and intermediates
Respiration: Pyruvates break down into CO2 (TCA cycle), generating ATP, NADH, FADH2, CO2

Question 14

What is the site of the electron transport chain in bacteria?

Answer 14

The cell membrane

Question 15

What is the Calvin cycle?

Answer 15

Converts CO2 into organic carbon molecules
Uses 18 ATPs to make 1 glucose

Question 16

What is the reverse TCA cycle?

Answer 16

Adds carbons from CO2 to smaller carbon chains to make larger ones, which are then split into Acetyl-CoA

Question 17

What is fatty acid biosynthesis?

Answer 17

Modular, stepwise addition of 2-carbon groups
Desaturation introduces double bonds
Regulated by feedback from high product levels

Question 18

What is polyketide antibiotic biosynthesis?

Answer 18

Modular, stepwise biosynthesis of antibiotics
Example: Erythromycin

Question 19

What is the difference between broad-spectrum and narrow-spectrum antibiotics?

Answer 19

Broad-spectrum: Treats unknown bacterial infections, but may kill good bacteria and promote resistance
Narrow-spectrum: Targets specific bacteria, requiring exact identification

Question 20

What is nitrogen fixation?

Answer 20

Fixing N2 to produce NH3 for biosynthesis, using 16 ATPs
Anabaena cyanobacteria use heterocysts for nitrogen fixation

Question 21

What regulates amino acid biosynthesis?

Answer 21

Negative feedback: If amino acids are present, biosynthesis is downregulated