organisation

Question 1

What do the human lungs provide an
exchange surface adapted for?

Answer 1

absorbing oxygen – needed for respiration – into the blood from the air transferring
carbon dioxide – produced by respiration – from the blood into the lungs then the air

Question 2

What is the structure of the respiratory system?

Answer 2

The human respiratory system
is adapted to allow air to pass in and out of the body, and for efficient gas exchange to happen. The lungs are enclosed in the thorax, surrounded and protected by 12 pairs of ribs. The ribs are moved by two sets of
intercostal muscles. There is a muscular
diaphragm below the lungs. The lungs are sealed within two airtight pleural membranes. These wrap around the lungs and line the rib cage. The trachea, or windpipe, branches into two bronchi – one bronchus to each lung. Rings of cartilage in the walls of the trachea help to keep it open as air is drawn in. The bronchi split into smaller branches and then into smaller tubes called bronchioles. Each bronchiole ends in a cluster of microscopic air sacs called alveoli.

Question 3

How is the human respiratory system adapted?

Answer 3

To allow air to pass in and out of the body, and for efficient gas exchange.

Question 4

The lungs are enclosed in the (a) surrounded and protected by (b) pairs of ribs.

Answer 4

(a) thorax
(b) 12

Question 5

What muscles move the ribs?

Answer 5

2 sets of intercostal muscles.

Question 6

The lungs are sealed within two airtight (a) (b)

Answer 6

(a) pleural
(b) membranes

Question 7

What do the trachea/ windpipe branch into?

Answer 7

2 bronchi, branching into each lung.

Question 8

What help to keep the walls of the trachea open as air is drawn in?

Answer 8

Rings of cartilage

Question 9

bronchi split into smaller branches and then into smaller tubes. what are these called?

Answer 9

bronchioles.

Question 10

Each bronchiole ends in a cluster of (a) air sacs called (b)

Answer 10

(a)microscopic
(b) alveoli

Question 11

What is gaseous exchange?

Answer 11

The exchange of gases occurs between the alveoli and blood in the capillaries
that supply the lungs. Capillaries cover 70% of the outside of alveoli, providing a large surface area for gases to diffuse across.

Question 12

How are the alveoli are adapted to provide a very large surface area for gaseous exchange?

Answer 12

small size - each alveolus is a small sphere about 300 μm in diameter, giving it a larger surface area to volume ratio than larger structures
number - there are around 700 million alveoli – ie 350 million per lung

Question 13

What is the role of enzymes in metabolism?

Answer 13

Large nutrient molecules are broken down into smaller ones by enzymes in the digestive system, this enables the molecules to be absorbed into the blood across the wall of the small intestine.

Question 14

What happens if an enzyme is in extreme conditions?

Answer 14

It denatures, stops working, loses shape.

Question 15

Enzymes bind (a) at key locations in their structure called (b)

Answer 15

(a) substrates
(b) active site

Question 16

Amylase (made in the (a) breaks down (b) Lipase (made in the (c) ; breaks down (d)) Protease (made in the (e); breaks down (f))

Answer 16

(a) mouth and pancreas
(b) complex carbohydrates
(c) pancreas
(d) fats
(e) pancreas
(f) proteins

Question 17

What is bile?

Answer 17

made in the liver, stored in the gall bladder and released into the small intestine. It neutralises the acid from the stomach to create a pH suitable for the enzymes of the small intestine and emulsifies fats so they can be more easily digested by lipase enzymes. ph of 8.2

Question 18

Does temperature increase the rate of fat breakdown by lipase?

Answer 18

Yes, temperature increases the rate of reaction

Question 19

The heart is a large (a) pump and is divided into 2 halves - the right-hand side and the left-hand side. The right-hand side of the heart is responsible for pumping (b) to the lungs. The left-hand side pumps (c) around the body. Each side of the heart consists of an (d) and a (e) which are two connected chambers.

Answer 19

(a) muscular
(b) deoxygenated blood
(c) oxygenated blood
(d) atrium
(e) ventricle

Question 20

What happens in the atria?

Answer 20

Where the blood collects when it enters the heart

Question 21

What happens in the ventricles?

Answer 21

Where the blood is pumped out of the heart to the lungs or around the body.

Question 22

What is the septum?

Answer 22

Separates the right-hand and left-hand side of the heart.

Question 23

Where is the tricuspid valve is located?

Answer 23

Between the right atrium and right ventricle

Question 24

Why does the tricuspid valve open?

Answer 24

Due to a build-up of pressure in the right atrium

Question 25

Where is the bicuspid valve is located?

Answer 25

Between the left atrium and left ventricle

Question 26

Why does the bicuspid valve open?

Answer 26

Due to a build-up of pressure, this time in the left atrium

Question 27

What does the semilunar valves stop?

Answer 27

The back flow of blood into the heart

Question 28

What are the 4 main blood vessels leading into and out of the heart?

Answer 28

The aorta, the vena cava, the pulmonary artery, the pulmonary vein

Question 29

What does the aorta do?

Answer 29

It carries oxygenated blood away from the left ventricle to the body.

Question 30

What does the vena cava do?

Answer 30

It carries deoxygenated blood from the body back to the heart.

Question 31

What does the pulmonary artery do?

Answer 31

Carries deoxygenated blood away from the right ventricle to the lungs

Question 32

What does the pulmonary vein do?

Answer 32

Returns oxygenated blood from the lungs to the heart

Question 33

What do specialised cells in the right atrium do?

Answer 33

Natural pacemakers. Generate electrical signals that make the heart contract independently of the nervous system.

Question 34

An artificial pacemaker is a small, (a)-operated electronic device implanted in a person’s (b) that sends out regular, adjustable (c) impulses to produce normal (d) of the heart.

Answer 34

(a) battery
(b) chest
(c) electrical
(d) contractions

Question 35

Why is capillaries being one cell thick good for diffusion?

Answer 35

Allow the exchange of molecules between the blood and the body’s cells - molecules can
diffuse across their walls.

Question 36

What is plasmas function?

Answer 36

Transporting carbon dioxide, digested food molecules, urea and hormones; distributing heat.

Question 37

What is red blood cells function?

Answer 37

Transporting oxygen.

Question 38

What is white blood cells function?

Answer 38

Ingesting pathogens and producing antibodies.

Question 39

What is platelets function?

Answer 39

Involved in blood clotting

Question 40

What is metastasis?

Answer 40

Malignant tumor, these tumours are cancerous and can break apart, move around the body and start new cancers in a process.

Question 41

What is the palisade mesophyll layer of the leaf adapted for

Answer 41

To absorb light efficiently as they are packed with many chloroplasts, are column-shaped and arranged closely together, towards the upper surface of the leaf.

Question 42

Why are spongy mesophyll
tissue is packed loosely?

Answer 42

For efficient gas exchange. The spongy mesophyll cells are covered by a thin layer of water. Gases dissolve in this water as they move into and out of the cells.

Question 43

The xylem transports (a) and minerals from the (b) up the plant (c) and into the leaves.

Answer 43

(a) water
(b) roots
(c) stem

Question 44

The phloem moves (a) substances that the plant has produced by (b) to where they are needed

Answer 44

(a) food
(b) photosynthesis

Question 45

Factors that affect the rate of transpiration

Answer 45

temperature
humidity
air movement
light intensity