Respiration and Gas Exchange in Humans

Question 1

Features/Adaptation of Gas Exchange in humans (4)

Answer 1

large surface area

thin surface

good blood supply

good ventilation of air

Question 2

Uses of energy in living organisms (7)

Answer 2

muscle contraction

protein synthesis

cell division

active transport

growth

passage of nerve impulses

maintenance of body temperature

Question 3

Define aerobic respiration (2)

Answer 3

chemical reactions in cells

use oxygen to break down nutrient molecules to release energy

Question 4

Aerobic respiration word equation

Answer 4

glucose + oxygen –> carbon dioxide + water

Question 5

Balanced chemical equation for aerobic respiration

Answer 5

C6H12O6 + 6O2 –> 6CO2 + 6H2O

Question 6

Define anaerobic respiration (2)

Answer 6

chemical reaction in cells

break down nutrient molecules to release energy without using oxygen

Question 7

Anaerobic respiration releases more energy per glucose molecule than aerobic respiration. True or False?

Answer 7

False

Question 8

Word equation for anaerobic respiration in yeast

Answer 8

glucose –> alcohol/ethanol + carbon dioxide

Question 9

Word equation for anaerobic respiration in muscles

Answer 9

glucose –> lactic acid

Question 10

Balanced chemical equation for anaerobic respiration in yeast

Answer 10

C6H12O6 –> 2C2H5OH + 2CO2

Question 11

What happens during vigorous exercise (3)

Answer 11

lactic acid builds up in muscles and blood

causes cramps

causes oxygen debt

Question 12

How is oxygen debt removed after exercise (2)

Answer 12

fast heart rate transports lactic acid in blood from muscles to liver

deeper/faster breathing supplied oxygen to break down lactic acid

Question 13

Composition of inspired air (3)

Answer 13

21% oxygen

0.04% carbon dioxide

variable water contents (depends on environment)

Question 14

Composition of expired air (3)

Answer 14

16% oxygen

4% carbon dioxide

saturated in terms of water content

Question 15

What cells produce mucus

Answer 15

goblet cells

Question 16

Relationship between exercise intensity and rate/depth of breathing (7)

Answer 16

cells respire faster during exercise to provide necessary energy for muscle contraction

hence produce more carbon dioxide

carbon dioxide is acidic

can alter blood ph/disrupt enzyme activity

trigger blood ph sensors in brain

brain sends impulse to lungs to increase breathing rate/volume

removes excess carbon dioxide

Question 17

Which is more damaging?

An increase in carbon dioxide concentration or a decrease in oxygen concentration

Answer 17

increase in carbon dioxide concentration

Question 18

Experiment to investigate anaerobic respiration (5)

Answer 18

boil glucose solution to sterilise/remove oxygen (for anaerobic respiration)

cool temperature (otherwise yeast will die)

place layer of oil above glucose to prevent oxygen from entering

yeast will anaerobically respire producing alcohol and carbon dioxide

limewater will turn cloudy showing carbon dioxide is present

Question 19

Direction of air entering lungs (6)

Answer 19

mouth

larynx

trachea

bronchi

bronchioles

alveoli

Question 20

Purpose of mucus

Answer 20

traps microorganisms/dust particles breathed in

Question 21

Where are cilia/ciliated cells found (2)

Answer 21

trachea lining

bronchi lining

Question 22

Purpose of cilia (2)

Answer 22

sweep in co-ordinated motion

move mucus up trachea to back of mouth to be swallowed

Question 23

Define ventilation

Answer 23

movement of air across alveolar surface

Question 24

What are alveoli covered in

Answer 24

capillaries

Question 25

Alveoli Adaptations (4)

Answer 25

thin walls moist lining large surface area high concentration gradient

Question 26

How does a moist lining improve gas exchange

Answer 26

gases dissolve before they diffuse

Question 27

Why does water vapour concentration increase in expired air

Answer 27

water evaporates from moist lining of alveoli due to warmth of body

Question 28

Components of cigarette smoke (3)

Answer 28

carbon monoxide nicotine tar

Question 29

How does carbon monoxide damage the body

Answer 29

reduces amount of oxygen blood can carry

Question 30

How does nicotine damage the body (3)

Answer 30

increases heart rate puts strain on heart increases risk of stroke

Question 31

How does tar damage the body (5)

Answer 31

causes breakdown of alveoli walls causes alveoli to merge together reduces surface area leads to emphysema increases chances of lung cancer

Question 32

Name 2 lung diseases

Answer 32

bronchitis emphysema

Question 33

What disease can smoking cause

Answer 33

Chronic obstructive pulmonary disease

Question 34

How does bronchitis affect the body (2)

Answer 34

causes inflammation which narrows airways causes mucus to block airways

Question 35

How does emphysema affect the body (3)

Answer 35

damages alveoli air becomes trapped in alveoli reduces gas exchange efficiency

Question 36

Name of gas exchange surface in humans

Answer 36

alveoli

Question 37

Name of the tissue that forms C-shaped structures in the wall of the trachea

Answer 37

cartilage

Question 38

Function of cartilage (2)

Answer 38

supports trachea allows movement of air

Question 39

Describe the effects on the thorax of contraction of the diaphragm (2)

Answer 39

volume increases pressure decreases