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

C6H12O6 → 2C3H6O3

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

Question 24

Name two industrial processes that rely on anaerobic respiration of yeast.

Answer 24

alcohol production (for consumption);
alcohol for fuel;
bread making

Question 25

The results for oxygen and carbon dioxide in the samples of breathed out air taken
before and after exercise are different.

Describe and explain these differences. [3]

Answer 25

after exercise less oxygen and more carbon dioxide / ora ;

use of data with % to quantify (for either oxygen or carbon dioxide) ;

more oxygen, absorbed / is needed / used up ;
more carbon dioxide, produced ;
more gas exchange ;
more respiration

Question 26

Explain why the changes shown in Table 4.2 occur during exercise.

Answer 26

muscles contract ;
need more energy ;
increase in need for oxygen ; ORA
removal of (more) carbon dioxide ;
(increase in) aerobic respiration ;
anaerobic respiration also occurs ;
developing oxygen debt

Question 27

Describe how the muscles identified in Fig. 4.1 work to move the forearm up.

Answer 27

biceps contracts
triceps relaxes

Question 28

Describe the athlete’s oxygen consumption during and after the race as shown in
Fig. 4.2., using figures in graph

Answer 28

before:
- oxygen consumption increases as exercise starts
- levels off / increase slows down during the race
– using data;; Maximum is 2.4dm3 min 1

after:
- starts to decrease, immediately at the end of the race / at 18
minutes
- gradually decreases after exercise

Question 29

Explain why the oxygen consumption does not return immediately to the resting level after the exercise is finished. [5]

Answer 29

oxygen debt
not enough oxygen supplied (to muscles) during exercise
to muscles
anaerobic respiration
lactic acid produced
lactic acid, broken down

Question 30

Compare the effect of walking and marathon running on energy reserves.

Answer 30

reserves last longer for walking / ora ;
(approx) 4 times longer

Question 31

Suggest which two energy reserves would be most readily available to muscles
during exercise.

+++ two food groups to which the energy reserves in Table 5.1 belong?

Answer 31

glucose and muscle glycogen

+++ fat and carbohydrate

Question 32

Suggest why athletes eat foods high in
(i) proteins, during training; [1]
(ii) carbohydrates, for three days before a marathon race. [2]

Answer 32

i) muscle, growth / development / repair

ii) to build up, energy stores ;
converted to fat / stored as fat ;

Question 33

Suggest and explain why a sprinter can use mainly anaerobic respiration during
the race, while a marathon runner needs to use aerobic respiration. [4]

Answer 33

short, time / distance, for sprint or long, time / distance, for marathon ;

sprint needs (lots of) energy quickly / marathon needs energy over long
period ;

sprint oxygen supply not sufficient / oxygen supplied during marathon ;

anaerobic does not need oxygen / aerobic needs oxygen ;

Question 34

Explain how, during a marathon race, the blood glucose concentration stays fairly
constant, but the mass of glycogen in the liver decreases. [2]

Answer 34

glycogen in liver broken down to glucose ;

glucose from liver enters the blood ;

Question 35

Name the organ where deamination takes place.

Answer 35

liver

Question 36

State the type of respiration shown in Fig. 5.1.
Explain your answer.
type of respiration
explanation

Answer 36

aerobic ;
carbon dioxide / water / no lactic acid, produced ;

Question 37

The urea produced is transported to the kidney, where it is excreted.

Describe how urea is transported in the blood to the kidney. [2]

Answer 37

soluble
in plasma

Question 38

kidney tubule & associated blood vessels.

name of part & functions

• LOOK AT DIAGRAM

Answer 38

A - glomerulus ;; filtering (blood) ;

B - capsule ;; collects filtrate / allows filtration ;

C - tubule ;; (selective) reabsorption ;

D - collecting duct ;; (re)absorbs water / passes urine to pelvis ;

Question 39

The volume of blood filtered by the kidneys is 1.18 dm3
min 1
.
(i) Calculate the total volume of blood filtered in 24 hours.

ii) total volume of urine produced in 24 hours is 1.7 dm3
, calculate the
percentage volume of the filtered blood excreted as urine in 24 hours.

Answer 39

1.18 × 60 × 24 / 1.18 × 1440
1699

——- 1.7 / 1700 × 100
0.1 (%)