Anaerobic Respiration and Respiratory Substrates

Question 1

What happens with the absence of oxygen?

Answer 1

Neither Krebs cycle nor the electron transfer chain will continue because soon all the FAD and NAD will be reduced

No FAD or NAD will be available to take up H+ produced during Krebs cycle so enzyme stopped working

Leaves glycolysis to be producing ATP

Question 2

Why will glycolysis grind to a halt in anaerobic respiration?

Answer 2

If no hydrogen is removed from products of pyruvate - hydrogen must be released by reduced NAD in order to regenerate NAD

A tiny supply of NAD leaving no NAD to take up hydrogen produced during glycolysis

Question 3

Where does anaerobic respiration occur?

Answer 3

• In plants , and microorganisms such as yeat , the pyruvate converted to ethanol and carbon dioxide
• In animals the pyruvate is converted to lacktate

Question 4

Anaerobic respiration leading to the production of ethanol occurs in what?

Answer 4

Certain bacteria and fungi (e.g yeast) as well as some cells of higher plants

e.g root cells under waterlogged conditions

Question 5

What is the equation of anaerboic respiration?

Answer 5

Pyruvate + reduced NAD -> ethanol + CO2 + oxidised NAD

Question 6

What is the application of anaerboic respiration?

Answer 6

Years in brewing industry

In brewing , ethanol is an important product

Yeast grown in anaerboic respiration which it ferments natural carbohydrates in plant products such as grapes (wine) or barely seeds(beer) into ethanol

Question 7

Why is anaerboic respiation useful if organism is fleeing from predator and muscles continue to work despite lack of oxygen?

Answer 7

NAD from glycolysis can accumlate and must be removed

The each pyruvate molecule takes up two hydrogen atoms from reduced NAD

Question 8

Equation of anaerobic respiration in animals

Answer 8

pyruvate + reduced NAD -> lactate + oxidised NAD

Question 9

How can energy be derived from two ways in cellular respiration?

Answer 9

• Substrate-level phosphorylation in glycolysis and Krebs cycle. This is direct transfer of phohsphate from a respiratory intermediate to ADP to produce ATP
• Oxidative phosphorylation in the electron transfer chain. This is indirect linking of energy from phosphate to ADP to produce ATP involving energy from hydrogen atoms that are carried on NAD and FAD. Cells produce most of ATP this way

Question 10

Why can’t anaerboic respiration progress into Krebs cycle?

Answer 10

Can either produce lactate or ethanol

Consequently it not availiable for Krebs cycle and not electron transfer chain can take place

Only ATP produced by anaerboic respiration is formed by glycolysis

Question 11

Steps of anaerboic respiation in mammals/animals

Answer 11

1. Glucose(6C)
2. Phosphrylated using 2x ATP - 2 ADP+ Pi
3. Produced phosphorylayed glucose (6C)
4. This converts into 2 x TP (3C)
5. ATP is then regnerates 2ADP + PI into 2ATP
6. Then regenerate 2x NAD to 2x reduced NADH
7. This produces 2 x pyruvate (3C)
8. 2x reduced NADH convert to 2 NAD (recycle to produce more reduced NAD)
9. This produces ethanol + CO2

Question 12

Steps of anaerobic respiration in plants -cytoplasm

yeast/plants/certain bacteria

Answer 12

1. Glucose(6C)
2. Phosphrylated using 2x ATP - 2 ADP+ Pi
3. Produced phosphorylayed glucose (6C)
4. This converts into 2 x TP (3C)
5. ATP is then regnerates 2ADP + PI into 2ATP
6. Then regenerate 2x NAD to 2x reduced NADH
7. This produces 2 x pyruvate (3C)
8. 2x reduced NADH convert to 2 NAD (recycle to produce more reduced NAD)
9. This produces ethanol + CO2

Question 13

Net gains of anaeroic respiration in mammals in plants

Answer 13

Uses - 2 x ATP 2 X NADH

PRODUCING - 4 X ATP , 2X NADH

NET GAIN - 2 XATP