Content
f) Respiration g) Gas exchange

f) Respiration g) Gas exchange
Content f) Respiration
2.33 understand that the process of respiration releases energy in living organisms
2.34 describe the differences between aerobic and anaerobic respiration
2.35 write the word equation and the balanced chemical symbol equation for aerobic respiration in living organisms
2.36 write the word equation for anaerobic respiration in plants and in animals
2.37 describe experiments to investigate the evolution of carbon dioxide and heat from respiring seeds or other suitable living organisms.

f) Respiration g) Gas exchange
Content g) Gas exchange
2.38 understand the role of diffusion in gas exchange
Flowering plants
2.39 understand gas exchange (of carbon dioxide and oxygen) in relation to respiration and photosynthesis
2.40 understand that respiration continues during the day and night, but that the net exchange of carbon dioxide and oxygen depends on the intensity of light
2.41 explain how the structure of the leaf is adapted for gas exchange
2.42 describe the role of stomata in gas exchange
2.43 describe experiments to investigate the effect of light on net gas exchange from a leaf, using hydrogen-carbonate indicator
Humans
2.44 describe the structure of the thorax, including the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes
2.45 understand the role of the intercostal muscles and the diaphragm in ventilation
2.46 explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries
2.47 understand the biological consequences of smoking in relation to the lungs and the circulatory system, including coronary heart disease
2.48 describe experiments to investigate the effect of exercise on breathing in humans.

What is respiration?
What is gaseous exchange?

What is respiration?
Respiration is the release of energy from the breakdown of glucose, by combining it with oxygen inside living cells.
What is gaseous exchange?

What is respiration?
Respiration is the release of energy from the breakdown of glucose, by combining it with oxygen inside living cells.
What is gaseous exchange?
Gaseous exchange is the movement of gases (oxygen and carbon dioxide) into and out of an organism.

Respiration – two sorts
Aerobic respiration - in the presence of oxygen.
Involves the complete breakdown of glucose.
Provides more energy.
End products in animals and plants: carbon dioxide and water

Respiration – two sorts
Aerobic respiration - in the presence of oxygen.
Involves the complete breakdown of glucose.
Provides more energy.
End products in animals and plants: carbon dioxide and water
Anaerobic respiration - in the absence of oxygen.
Involves the incomplete breakdown of glucose.
Provides less energy.
End product in animals – lactic acid. End product in plants ethanol

Aerobic respiration
Glucose + oxygen  carbon dioxide + water + energy

Aerobic respiration
Glucose + oxygen  carbon dioxide + water + energy
C
6
H
12
O
6
+ 6O
2
 6CO
2
+ 6H
2
O + energy

Aerobic respiration
Glucose + oxygen  carbon dioxide + water + energy
C
6
H
12
O
6
+ 6O
2
 6CO
2
+ 6H
2
O + energy
What do you notice?

Photosynthesis
6CO
2
+ 6H
2
O C
6
H
12
O
6
+ 6O
2

Blood capillary
Glucose
Muscle cell

Blood capillary
Glucose
Glucose + Oxygen
Glucose and oxygen diffuse from the blood into the muscle cell
Muscle cell

Blood capillary
Glucose
Deoxygenated red blood cells
Glucose + Oxygen  Carbon dioxide + Water
Muscle cell
Glucose and oxygen diffuse from the blood into the muscle cell
Carbon dioxide and water diffuse from the muscle cell into the blood

Blood capillary
Glucose
Deoxygenated red blood cells
Energy
Glucose + Oxygen  Carbon dioxide + Water
Glucose and oxygen diffuse from the blood into the muscle cell
Muscle cell
Energy is used for muscle contraction
Carbon dioxide and water diffuse from the muscle cell into the blood

Levels of Organisation

Levels of Organisation
Mitochondria organelles inside the cell where cellular respiration takes place.
They absorb glucose and oxygen, release the energy and then convert it into forms that are usable by the cell.
Mitochondria are more numerous in active cells such as muscle cells.

Why anaerobic respiration?
If it is so inefficient compared with aerobic respiration, why do cells bother?
Sometimes our muscles are working so hard that the lungs and bloodstream cannot deliver oxygen fast enough, so the muscles must respire anaerobically.
This can lead to a build up of lactic acid in the muscle.

Why anaerobic respiration?
If it is so inefficient compared with aerobic respiration, why do cells bother?
A lactic acid build-up in muscles can result in cramp, an unpleasant and often painful sensation caused by muscle contraction or overshortening.

Why anaerobic respiration?
If it is so inefficient compared with aerobic respiration, why do cells bother?
In order to break down the lactic acid the body needs more oxygen 

Why anaerobic respiration?
If it is so inefficient compared with aerobic respiration, why do cells bother?

Anaerobic respiration in plants

Anaerobic respiration in plants
Glucose  ethanol + carbon dioxide + energy

Anaerobic respiration in plants
Glucose  ethanol + carbon dioxide + energy
C
6
H
12
O
6
 2C
2
H
5
OH + 2CO
2

Anaerobic respiration in plants
Glucose  ethanol + carbon dioxide + energy
C
6
H
12
O
6
 2C
2
H
5
OH + 2CO
2
In plants, anaerobic respiration (respiration without oxygen) is known as fermentation. This process is commonly used to our advantage in the production of beer and ales, and wine.

Aerobic v Anaerobic

Aerobic v Anaerobic
AEROBIC
A very efficient method of producing energy.
ANAEROBIC
Inefficient (incomplete breakdown of glucose) – releases 1/20 th energy compared to aerobic.

Aerobic v Anaerobic
AEROBIC
A very efficient method of producing energy.
Occurs during normal daily activity.
ANAEROBIC
Inefficient (incomplete breakdown of glucose) – releases 1/20 th energy compared to aerobic.
Produces energy much faster over a short time period. Eg. sprinting

Aerobic v Anaerobic
AEROBIC ANAEROBIC
A very efficient method of producing energy.
Occurs during normal daily activity.
Produces energy more slowly than anaerobic.
Inefficient (incomplete breakdown of glucose) – releases 1/20 th energy compared to aerobic.
Produces energy much faster over a short time period. Eg. sprinting
Build-up of waste products eventually stops the muscle from working

f) Respiration g) Gas exchange
Content g) Gas exchange
2.38 understand the role of diffusion in gas exchange
Flowering plants
2.39 understand gas exchange (of carbon dioxide and oxygen) in relation to respiration and photosynthesis
2.40 understand that respiration continues during the day and night, but that the net exchange of carbon dioxide and oxygen depends on the intensity of light
2.41 explain how the structure of the leaf is adapted for gas exchange
2.42 describe the role of stomata in gas exchange
2.43 describe experiments to investigate the effect of light on net gas exchange from a leaf, using hydrogen-carbonate indicator
Humans
2.44 describe the structure of the thorax, including the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes
2.45 understand the role of the intercostal muscles and the diaphragm in ventilation
2.46 explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries
2.47 understand the biological consequences of smoking in relation to the lungs and the circulatory system, including coronary heart disease
2.48 describe experiments to investigate the effect of exercise on breathing in humans.

What is respiration?
Respiration is the release of energy from the breakdown of glucose, by combining it with oxygen inside living cells.
What is gaseous exchange?
Gaseous exchange is the movement of gases (oxygen and carbon dioxide) into and out of an organism.

What is gaseous exchange?
Gaseous exchange is the movement of gases (oxygen and carbon dioxide) into and out of an organism.
Gaseous exchange is brought about by the actions of the breathing system (also referred to in some textbooks as the respiratory system)

The Breathing System

The Breathing System
Trachea – surrounded by rings of cartilage to stop it collapsing

The Breathing System
Ribs – these protect the contents of the thorax. There are 12 pairs of ribs in both men and women.
Trachea – surrounded by rings of cartilage to stop it collapsing

The Breathing System
Ribs – these protect the contents of the thorax. There are 12 pairs of ribs in both men and women.
Rib muscles - the intercostals. Raise and lower the rib cage
Trachea – surrounded by rings of cartilage to stop it collapsing

The Breathing System
Ribs – these protect the contents of the thorax. There are 12 pairs of ribs in both men and women.
Rib muscles - the intercostals. Raise and lower the rib cage
Trachea – surrounded by rings of cartilage to stop it collapsing
Left lung

The Breathing System
Ribs – these protect the contents of the thorax. There are 12 pairs of ribs in both men and women.
Rib muscles - the intercostals. Raise and lower the rib cage
Trachea – surrounded by rings of cartilage to stop it collapsing
Left lung
Diaphragm – a sheet of muscle used in the mechanism of breathing

The Breathing System
Ribs – these protect the contents of the thorax. There are 12 pairs of ribs in both men and women.
Rib muscles - the intercostals. Raise and lower the rib cage
Right bronchus – a branch of the trachea
Trachea – surrounded by rings of cartilage to stop it collapsing
Left lung
Diaphragm – a sheet of muscle used in the mechanism of breathing

The Breathing System
Ribs – these protect the contents of the thorax. There are 12 pairs of ribs in both men and women.
Rib muscles - the intercostals. Raise and lower the rib cage
Right bronchus – a branch of the trachea
Trachea – surrounded by rings of cartilage to stop it collapsing
Left lung
Bronchiole - a smaller branch of the bronchus
Diaphragm – a sheet of muscle used in the mechanism of breathing

The Breathing System
Ribs – these protect the contents of the thorax. There are 12 pairs of ribs in both men and women.
Rib muscles - the intercostals. Raise and lower the rib cage
Right bronchus – a branch of the trachea
Trachea – surrounded by rings of cartilage to stop it collapsing
Left lung
Bronchiole - a smaller branch of the bronchus
Diaphragm – a sheet of muscle used in the mechanism of breathing
Alveoli - clusters of grape-like air sacs where gas exchange takes place

The Breathing System
Ribs – these protect the contents of the thorax. There are 12 pairs of ribs in both men and women.
Rib muscles - the intercostals. Raise and lower the rib cage
Right bronchus – a branch of the trachea
Trachea – surrounded by rings of cartilage to stop it collapsing
Left lung
Bronchiole - a smaller branch of the bronchus
Diaphragm – a sheet of muscle used in the mechanism of breathing
Alveoli - clusters of grape-like air sacs where gas exchange takes place

Alveolus (plural alveoli)
Where oxygen and carbon dioxide move between the lungs and the blood stream.

Alveolus
Bronchiole
There are millions of alveoli in each lung, very close to blood capillaries

1 Alveolus
Bronchiole
1. Deoxygenated blood flow from the tissues, rich in carbon dioxide

Bronchiole
Alveolus
2
2. Carbon dioxide diffuses out of the blood stream into the alveoli, and then into the bronchiole

Alveolus
Bronchiole
3
3. Oxygen diffuses from the bronchiole into the alveoli and then into the red blood cells.

Alveolus
Bronchiole 4
4. Oxygenated blood now leaves the alveoli and carries oxygen to the tissues.

Features of the alveoli:

Features of the alveoli:
1. A very large, moist surface area.

Features of the alveoli:
1. A very large, moist surface area.
2. An excellent capillary blood supply

Features of the alveoli:
1. A very large, moist surface area.
2. An excellent capillary blood supply
3. Very thin cell membrane separating blood and lung

Ventilation
INHALATION = taking air into the lungs
EXHALATION = removing air from the lungs

Ventilation

Diaphragm moves downwards and becomes flatter.
Ventilation
BREATHING IN
Rib cage moves upwards and outwards.
Overall effect: volume of the thorax increases, pressure decreases, so air is drawn IN

Diaphragm moves upwards and becomes dome shaped.
Ventilation
BREATHING OUT
Rib cage moves downwards and inwards.
Overall effect: volume of the thorax decreases, pressure increases, so air is pushed OUT

f) Respiration g) Gas exchange
Content g) Gas exchange
2.38 understand the role of diffusion in gas exchange
Flowering plants
2.39 understand gas exchange (of carbon dioxide and oxygen) in relation to respiration and photosynthesis
2.40 understand that respiration continues during the day and night, but that the net exchange of carbon dioxide and oxygen depends on the intensity of light
2.41 explain how the structure of the leaf is adapted for gas exchange
2.42 describe the role of stomata in gas exchange
2.43 describe experiments to investigate the effect of light on net gas exchange from a leaf, using hydrogen-carbonate indicator
Humans
2.44 describe the structure of the thorax, including the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranes
2.45 understand the role of the intercostal muscles and the diaphragm in ventilation
2.46 explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries
2.47 understand the biological consequences of smoking in relation to the lungs and the circulatory system, including coronary heart disease
2.48 describe experiments to investigate the effect of exercise on breathing in humans.

Leaf adaptations
Cross section through a leaf
Inter-cellular air spaces
Lower epidermis – note the presence here of stomata (tiny pores surrounded by guard cells).

Leaf adaptations
Cross section through a leaf
Lower epidermis – note the presence here of stomata (tiny pores surrounded by guard cells).

Leaf adaptations
Cross section through a leaf
Oxygen is absorbed and carbon dioxide is released direct from cells to air spaces during respiration.

Gaseous exchange in plants
6CO
2
+ 6H
2
O  C
6
H
12
O
6
+ 6O
2
C
6
H
12
O
6
+ 6O
2
 6CO
2
+ 6H
2
O

Gaseous exchange in plants
6CO
2
+ 6H
2
O  C
6
H
12
O
6
+ 6O
2
C
6
H
12
O
6
+ 6O
2
 6CO
2
+ 6H
2
O

+
-
12 midnight 12 mid-day
Time of Day
12 midnight

+
-
12 midnight 12 mid-day
Time of Day
12 midnight

+
-
12 midnight 12 mid-day
Time of Day
12 midnight

+
-
12 midnight 12 mid-day
Time of Day
12 midnight

+
-
12 midnight 12 mid-day
Time of Day
12 midnight

+ photosynthesis
-
12 midnight 12 mid-day
Time of Day
12 midnight respiration

+
-
12 midnight
Compensation point
12 mid-day
Time of Day
Compensation point
12 midnight

End of Section 2 Lesson 4
Respiration
Gaseous exchange