c07 respiration in humans

Question 1

definition of aerobic respiration

Answer 1

The release of energy by the breakdown of glucose in the presence of oxygen. Carbon dioxide and water are released as metabolic waste products. Aerobic respiration releases a large amount of energy.

Question 2

ways that energy are used

Answer 2

Synthesis of proteins from amino acids (enzymes, hormones, antibodies)

Building up of new protoplasm for growth, repair & cell division

Muscular contractions of the heart, in respiratory movements and to bring

about movements

Active transport for examples: absorption of digested food by small

intestine, absorption of mineral salts by root hair cells

Transmission of nerve impulses

Maintenance of constant body temperature

Question 3

definition of anaerobic respiration

Answer 3

The release if energy by the breakdown of glucose in the absence of oxygen. Anaerobic respiration releases a relatively small amount of energy.

Question 4

muscles cells are the start of a race

Answer 4

muscle cells first carry out aerobic respiration because there is sufficient oxygen transported to the muscles

Person breathes faster and deeper (explanation) to take in oxygen and remove carbon dioxide at a faster rate

heart muscles contracts faster (explanation) to transport oxygen and glucose to muscles faster for skeletal muscles to respire faster to release more energy to contract faster

Question 5

muscle cells during a race

Answer 5

There is a limit to the increase in breathing rate and heartbeat (reach a maximum)

When insufficient oxygen is carried to the muscles, anaerobic respiration occurs to release a small amount of energy for muscles to continue to contracting faster during the race

Muscles incur an oxygen debt due to the lactic acid produced in the muscle cells during anaerobic respiration

Question 6

muscle cells immediately after the race

Answer 6

Breathing rate and heartbeat remains high for some time.

To transport lactic acid from the muscle to the liver faster and sufficient oxygen to muscle and liver cells faster to remove oxygen debt (break down all the lactic acid)

Oxygen debt is removed in the liver when lactic acid is oxidised to release energy, where the energy is used to convert remaining lactic acid into glucose which can be used in aerobic respiration

Question 7

nose

Answer 7

Air enters body through 2 external nostrils leading to two nasal passages that are lined with mucus membrane

Walls of nostrils have a fringe of hairs

Advantages of breathing through nose:
Dust and bacteria in the air are trapped by the hairs and the mucus membrane found on the walls of the nostrils

Air is warmed and moistened through the nasal passages

Harmful chemicals can be detected by sensory cells in the mucus membrane

Question 8

pharynx

Answer 8

Air passes through the nasal passage and into the pharynx. The air then passes through the larynx and into the trachea.

Question 9

function of larynx

Answer 9

let air pass through pharynx and into the trachea leading to the lungs

Question 10

function of trachea

Answer 10

allow air to pass through into the lungs, have gland cells secrete mucus to trap bacteria and dust

Question 11

trachea

Answer 11

Supported by C-shaped rings of cartilage (connective tissues), to keep the trachea open

Epithelium next to lumen contains 2 cells: gland cells and cilliated cells

Gland cells:

Secrete mucus to trap dust particles and bacteria

Cilliated cells:

Role of cillia: Have hair-like structures, cillia, on the surface of the cell that sweep the dust-trapped mucus up the trachea to the pharynx to be swallowed into the oesophagus

Question 12

Bronchis function

Answer 12

ciliated cells’ cilia sweep dust trapped mucus up the trachea

Question 13

Bronchioles function

Answer 13

the smallest tubes, air passes through into the alveoli

Question 14

bronchi and bronchioles

Answer 14

Trachea divides into two tubes: 2 bronchus (singular), or the bronchi (plural)

Bronchus branches repeatedly to form numerous bronchioles ending in alveoli (cluster of alveolus)

Question 15

function of alveoli

Answer 15

where diffusion of oxygen and carbon dioxide through the alveolar walls takes place

Question 16

alveoli

Answer 16

Diffusion of oxygen and carbon dioxide takes place through the alveolar wall

Numerous alveoli provides a very large surface area (equivalent to the size of a tennis court) for diffusion of oxygen and carbon dioxide to occur faster.

Question 17

adaptations of lungs

Answer 17

1. Large number of alveoli in the lungs

provide a large surface are for rapid diffusion of oxygen and carbon dioxide.

2. The walls of the alveoli are richly supplied with blood capillaries.

The flow of blood maintains concentration gradient of gases. This ensures rapid exchange of gases (O2 from alveoli into blood, CO2 from blood into alveoli).

Question 18

adaptations of alveolus

Answer 18

1. The alveolar wall is only one cell thick.

short diffusion distance, ensures a faster rate of diffusion of gases

2. A thin film of moisture covers the inner surface of the alveolus.

allows oxygen to dissolve in it and diffuse through the alveolar wall into the blood capillary

Question 19

how is oxygen transported around the body

Answer 19

Oxygen combines with haemoglobin in the red blood cells to form oxyhaemoglobin. (reversible)

Binding of oxygen to haemoglobin does not involve enzymes

When blood passes through organ with low oxygen concentration, oxyhaemoglobin will release its oxygen to the respiring cells