Module 11 + 12

Question 1

What are the three processes by which ATP can be produced (two are cellular and the other is fermentation)? Compare and contrast the three mechanisms.

Answer 1

1.Aerobic=O2 as final acceptor
2.Anaerobic-another inorganic molecule is the final electron acceptor (path varies by the organism)
3.Fermentation-organic molecule is the final electron acceptor

Question 2

Which pathway (step) in aerobic respiration requires oxygen, which does not require oxygen

Answer 2

ETC requires while glycolysis and Krebs

Question 3

What is chemiosmosis? What pathway (step) of aerobic respiration does it occur in?

Answer 3

Chemical gradient due to pH and an osmotic gradient due to higher concentration outside the cell than inside; occurs during the Electron Transport Chain

Question 4

What is substrate level phosphorylation? What pathway (steps) does in occur in aerobic respiration?

Answer 4

The high energy phosphate is transferred from a substrate to ADP; occurs in glycolysis and Kreb’s cycle

Question 5

What is the total ATP produced from aerobic respiration/glucose molecule? How does a prokaryote compare to a eukaryote?

Answer 5

The total net ATP for a prokaryote is 38 but only 36 for eukaryotes because two are used to move from the cytoplasm to the mitochondrial matrix

Question 6

What is fermentation and what are the pathways (steps)? How does it differ from aerobic respiration? What pathway (step) of aerobic respiration is the same in fermentation?

Answer 6

Releases energy from organic molecules.

Glycolysis

Some fermentation cycle (depends on the organism as to which cycles they do)

Does not require oxygen but can occur when around. No Krebs or ETC

Glycolysis

Question 7

How much ATP is produced in each pathway (step) of fermentation?

Answer 7

Glycolysis- 2 ATP

Fermentation- 0 ATP

Question 8

What are the three (main) products possible from fermentation?

Answer 8

Acid, Gas, Alcohol

Question 9

What is the main importance of each pathway (step) in a fermentation pathway?

Answer 9

Glycolysis- produce ATP and connects electrons to electron carriers

Fermentation- get the electrons off of the carriers. Oxygen is not around and the organism needs some energy. Recycles coenzymes (oxidizes them) and can keep doing glycolysis.

Question 10

Compare and contrast lactic acid fermentation and alcohol fermentation.

Answer 10

Lactic acid-
–First step glycolysis
–2 pyruvic acid-> steps-> lactic acid
–The fermentation step oxidizes the reduced coenzymes
Importance
–Lactobacillus sp.-> acidophilus milk
–Streptococcus sp. (plaque formers)-> then fermentation can cause decay

Alcohol fermentation
–Begins with glycolysis
–2 pyruvic acid-> steps-> ethanol + CO2
–Fermentation oxidizes the reduced coenzymes
–Commonly found in Saccharomyces cerevisiae
–Eukaryotic
–Single celled fungi-yeast
–Baker’s yeast or bread yeast
Importance
-Food industry-bread and beer industry
-Gasohol- part of NE’s economy (ethanol plants)
-Others (table of examples) cheese, fuel, vinegar

Question 11

Why is fermentation important to us (benefits)?

Answer 11

For gas, beer, bread, gasohol, food, cheese, fuel, vinegar.

Question 12

What is an exoenzyme? Why does a bacterium have to produce exoenzymes to break down proteins

Answer 12

Works outside of a cell to cut proteins up into smaller pieces to do bring into the cell. The protein is too large to move into the cell but amino acids are small enough to.