UNIT 12 Respiration

Question 1

uses of energy in living organisms,

including:

Answer 1

muscle contraction,

protein synthesis,

cell division,

active transport,

growth,

the passage of nerve impulses

& the maintenance of a constant body temperature

Question 2

Investigate and describe the effect of temperature on respiration in yeast

y-axis = respiration in yeast
x-axis = temperature

What does respiration use?
Too low temp? Too high?

Answer 2

ENZYMES.

temp too low = less collisions

35 degrees Celsius - optimal temp for maximum respiration. Maximum number of collisions without denaturing

Temp too high = enzymes denature

Question 3

What is yeast?

Answer 3

Single-celled fungus

Cell wall of chitin

Question 4

Describe aerobic respiration

Answer 4

the chemical reactions in cells that use oxygen to break down
nutrient molecules to release energy

breakdown of glucose to release energy using oxygen

Question 5

Pro & con of aerobic

Answer 5

Pro: releases more energy per glucose molecule (38 ATP per glucose molecule)

Con: requires oxygen

Question 6

word & symbol equation for aerobic respiration

Answer 6

glucose + oxygen → carbon dioxide + water

C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 7

Describe anaerobic respiration

Answer 7

the chemical reactions in cells that break down nutrient
molecules to release energy without using oxygen

breakdown of glucose to release energy without oxygen

Question 8

this produces less etc. than aerobic?

Answer 8

ANaerobic respiration releases much LESS energy per glucose molecule than aerobic
respiration

Question 9

Pros, cons

Answer 9

Pros: does not require oxygen

Cons: produces much less energy per glucose molecule (2 ATP per glucose)

& produces lactic acid creating an oxygen debt that must be paid back later

Question 10

word & symbol equation for anaerobic respiration in yeast

Answer 10

glucose → alcohol + carbon dioxide

C6H12O6 → 2C2H5OH + 2CO2

Question 11

word equation for anaerobic respiration in muscles during vigorous exercise

IN ANIMALS

Answer 11

glucose → lactic acid

Question 12

lactic acid … during exercise does what?

Answer 12

builds up in muscles and blood during vigorous exercise causing an oxygen debt

Question 13

Outline how the oxygen debt is removed after exercise

1.

Answer 13

1. continuation of fast heart rate to transport lactic acid in the blood from the muscles to the liver

Question 14

2.

Answer 14

2. continuation of deeper and faster breathing

to supply oxygen for aerobic respiration of lactic acid [back to pyruvate]

Question 15

3.

Answer 15

3. aerobic respiration of lactic acid in the liver

Question 16

Investigate & describe effect of temp on respiration in yeast -

What happens when we can’t get enough oxygen for aerobic respiration?

1. When does this happen?

Answer 16

Vigorous exercise => bodies aerobically respire at a high rate

During period, oxygen is used faster in body cells than it can be replaced by gas exchange; breathing deeper & heart pumping hard bc body is re-paying oxygen debt since -

SO

Question 17

2. SO how do body cells continue producing more energy?

Answer 17

So if body cells run out of oxygen they can still produce more energy using anaerobic respiration

BUT much less efficient & creates lactic acid

Question 18

3.

Answer 18

Anaerobic respiration creates an oxygen debt as oxygen is required to convert lactic acid back to pyruvic acid in the liver

Question 19

Define respiration [2]

Answer 19

chemical REACTIONS that breakdown glucose

to release energy

inside cells

Question 20

Explain why there is a steep increase in the man’s oxygen consumption at the start of the exercise [4]

Answer 20

📌 increase in muscle contraction

📌 increase in demand for energy, ATP

📌 increase in rate of respiration

📌 aerobic respiration

[heart beats faster]

Question 21

10 mins after man had stopped rowing for O2 consumption to decrease to resting

draw line btwn 20-35 to show change in O2 consumption after exer. stopped [2]

Answer 21

line decreases immediately at 20 min

line reaches 0.2 dm^3 min^-1 at 30 min

Question 22

Explain why the man’s oxygen consumption did not return to the resting value immediately after exercise [4]

Answer 22

📌 oxygen debt

📌 during exercise oxygen not supplied fast enough [from lung]

📌 to muscles

📌 anaerobic respiration occurred doing exercise

📌 lactic acid produced, builds up in muscle

Question 23

Describe what oxygen debt is

Answer 23

lactic acid builds up in muscles & blood after vigorous exercise

this requires oxygen to be broken down

amount required = oxygen debt