Ch 21 Respiration

Question 1

Which specific animal cell type can overcome hypoxia by switching to anaerobic respiration:

Answer 1

Skeletal muscle cell
Without oxygen to act as final electron acceptor, pyruvate is used instead. Pyruvate is reduced to Lactic acid by NADH. The NAD is recycled for continual glycolysis. Glycolysis continues to produce ATP, which is used by muscle cells.

Question 2

Structure of mitochondrion:

Answer 2

Mitochondrion is bounded by double membrane. Outer membrane controls the movement of substances into and out of the body.
The inner membrane is highly folded to form cristae. The cristae is packed with enzymes involved in the reaction of respiration. It greatly increases the surface area for enzymes and electron carriers for oxidative phosphorylation. The space enclosed by the inner membrane is filled with a fluid called the mitochondrial matrix. It contains enzymes and provide a fluid medium for Krebs cycle.

Question 3

Cells that have a lot of mitochondrion:

Answer 3

Liver cell, muscle cell, synaptic knob ,epithelial cell of an intestinal villus and sperm cell

Question 4

The two types of respiration:

Answer 4

Aerobic respiration and Anaerobic respiration

Question 5

(Aerobic respiration) 1st step:

Answer 5

Glycolysis occurs in the cytoplasm. It does not require oxygen.
Glucose is first activated by ATP. (which means phosphorylation) Glucose is broken down into two molecules of triose phosphate by using energy from ATP. Triose phosphate is oxidized to pyruvate. NADH and ATP are formed.

Question 6

Bridging between glycolysis and Krebs cycle:

Answer 6

Pyruvate is changed to acetyl-CoA. Carbon dioxide and NADH are released

Question 7

(Aerobic respiration) 2nd step:

Answer 7

Krebs cycle occurs in the mitochondrial matrix. Acetyl-coA combines with 4-C compound already present in the mitochondrial matrix to form 6-C compound which is oxidized step by step to regenerate the original 4-C compound. Co2 is released. NADH, FADH and ATP are formed.

Question 8

(Aerobic respiration) 3rd step:

Answer 8

Oxidative phosphorylation occurs on the inner membrane of mitochondrion. NADH and FADH loses hydrogen. NAD and FAD are regenrated. Hydrogen atom is split into hydrogen ions and electrons. The electron passes through the electron transport chain at the inner membrane of mitochondrian. The energy released is used for oxidative phosphorylation to form ATP. The hydrogen ions and electrons are finally transferred to final electron acceptor, oxygen, to form water.

Question 9

Facts of ATP:

Answer 9

ATP acts as an energy carrier in the cell which it is made, cannot be transferred from cell to cell.

Question 10

How can ATP provide provide energy for biological processes?

Answer 10

ATP is readily broken down into ADP and phosphate with the release of energy.

Question 11

Precaution to ensure the yeast are undergoing anaerobic respiration:

Answer 11

Boil the water to remove the oxygen dissolved.
Add paraffin oil on the boiled water to prevent oxygen from dissolving into the solution.

Question 12

Another industrial application of yeast:

Answer 12

Brewing of wine and beer

Question 13

similarities of photosynthesis and respiration.

Answer 13

ATP is produced through the transfer of electrons along the electron transport chain at the inner membrane of chloroplasts and the mitochondrion.

Question 14

With specific animal cell type, how this cell can be overcome hypoxia (oxygen deficient condition)

Answer 14

Skeletal muscle cell.
Without oxygen to act as the final electron acceptor. Pyruvate is used instead. Pyruvate is reduced to lactic acid by NADH. NAD is recycled for continual glycolysis. Glycolysis continues to produce ATP which is used by muscle cell.

Question 15

During flooding, plants that are not tolerant to hypoxia wilt. Explain.

Answer 15

In flooded soil, non tolerant plants cannot switch to anaerobic respiration, much less ATP is produced than tolerant plants. The root cannot carry out active transport to uptake minerals. As a result, water absorbed is much less. Meanwhile. transpiration continues. When the rate of transpiration is higher than the rate of water absorption, thin walled cells loses turgidity. The plants cannot support themselves and wilt.

Question 16

Before the experiment started, the clip were opened for a while and then closed. Why is this necessary?

Answer 16

This is to equalise the pressure in both arms of the U-shaped capillary , to ensures that the liquid levels in both arms are the same at the beginning of the experiment.

Question 17

Why does the blood lactic acid level rise after the man performs exercise?

Answer 17

The energy demand for skeletal muscles cell during strenuous exercise increases. When there is insufficient supply of oxygen for completing oxidation of glucose in skeletal muscle. The skeletal muscle cells carry out anaerobic respiration to provide additional energy in very short time for muscle contraction. lactic acid is produced in the muscle cells and diffuses to blood. Therefore, the blood lactic acid level rises. 

Question 18

In 100 meter race, the amount of oxygen breathed in and blood lactic acid level for athletes are different from non-athletes. This makes athletes perform much better than non-athletes explain.

Answer 18

Athletes have higher ventilation rate and cardiac output the non-athletes. More oxygen is provided to skeletal muscle cells for aerobic respiration. More energy is released for muscular contraction than non-athletes. Athletes carries out anaerobic respiration much lately than non-athletes. Less lactic acid accumulates in the muscle and muscle fatigue occurs later.

Question 19

Two difference between the cyclic processes of respiration and photosynthesis.

Answer 19

In Krebs cycle,  carbon dioxide is removed from substrates. While, in the Calvin cycle, carbon dioxide is fixed by 5-C compound. 
In Krebs cycle,NADH and ATP are formed. While in the Calvin cycle, NADPH and ATP are used.