B2.2

Question 1

Why is surface area to volume ratio important ?

Answer 1

To see how nutrients can diffuse directly into the organism to sustain life as diffusion distances are small. The larger the animal, the lower the SA to volume ratio

Question 2

How can you maximise the rate of diffusion of oxygen into the bloodstream

Answer 2

Have many alveoli in the lungs to increase the S.A. of it

Question 3

Where is digested food molecules absorbed into

Answer 3

Into the blood from the small intestine

Question 4

How do you maximise the rate of diffusion for the small intestine

Answer 4

The walls of the small intestine contain fingerlike villi to increase S.A. of the intestine wall.

Question 5

Why are transport systems needed in animals?

Answer 5

The circulatory system is the main transport system. The blood carried materials to where they’re required. The liver produces urea when it breaks down the excess amino acids. Urea is toxic so it is transported to the kidney where it’s removed

Question 6

Why are transport systems needed in plants?

Answer 6

Xylem tubes carry water and mineral ions around a plant and phloem tubes transport sugars and amino acids

Question 7

What is the circulatory system made up of?

Answer 7

Your heart and your blood vessels

Question 8

Why is the circulatory system known as a closed system

Answer 8

Because the blood remains within the structures

Question 9

Where does the blood transport to

Answer 9

It transports around the body to the cells that need them
Oxygen and glucose for respiration
Co2as a waste product

Question 10

How many times does the blood circulate the heart in one circuit?

Answer 10

Twice

Called the double circulatory system

Question 11

What does oxygenated blood mean

Answer 11

High levels of oxygen

Question 12

What does deoxygenated blood mean

Answer 12

Low levels of oxygen

Question 13

Where does your heart pump blood to.

Answer 13

Body organs and tissues

Question 14

Where does co2, glucose and oxygen diffuse to.

Answer 14

Co2 -out of the cells into the blood

Glucose and oxygen- out of the blood and into the cells

Question 15

What does the lungs do to co2, glucose and oxygen ?

Answer 15

It diffuses co2out of the blood and into the body

It diffuses in the other two into the blood

Question 16

What are the three main blood vessels

Answer 16

Arteries, capillaries and veins

Question 17

What do arteries do?

Answer 17

They carry blood vessels away from the heart under high pressure

Question 18

What do veins do

Answer 18

They return blood back to the heart and they have valves to stop blood flowing the wrong way

Question 19

What do capillaries do

Answer 19

They link the arteries and veins in tissues and organs. They then form a network so every cell is close to a capillary. Their semi permeable walls are one cell thick so substances can move easily through them

Question 20

What do strong contractions of the heart cause

Answer 20

High blood pressure

Question 21

What Is your heart made up of

Answer 21

Cardiac muscle. They contract without receiving a nerve impulse from your brain.

Question 22

What are the four chambers called

Answer 22

The two top ones are the atria

The two bottom ones are the ventricles

Question 23

What separates the Chambers

Answer 23

Valves

Question 24

What are the four things found in the blood

Answer 24

Red blood cells
White blood cells
Plasma
Platelets

Question 25

What does the xylem tissue transport

Answer 25

Water and mineral ions from the roots to the stem, leaves and flowers. Water diffuses into roots via osmosis. Mineral ions are taken by active transport

Question 26

What does the phloem tissue transport

Answer 26

Dissolved sugars produced during photosynthesis and other soluble food molecules from the leaves to all other areas of the plant. This is called translocation.

Question 27

What do the phloem and the xylem tissue form a structure called

Answer 27

A vascular bundle

Question 28

What are xylem vessels made up from

Answer 28

Dead xylem cells. No cell walls at the endz of these cells.

Question 29

Structure of the phloem

Answer 29

Phloem vessels are made form living cells. The cell walls of these cells don’t completely break down. Instead plates are formed- small holes in the end wall which allows the dissolved sugars to pass through. The connection of the phloem cells effectively forms a tube which allows dissolved sugars to be transported

Question 30

How do vascular bundles provide support in the leaf

Answer 30

They form a network that supports the softer leafy tissue

Question 31

How do vascular bundles provide support in the stem

Answer 31

They’re located around the outer edge providing the stem with strength to resist the bending in the breeze

Question 32

How do vascular bundles provide support in the root

Answer 32

Found in the centre to enable the root to act as an anchor so the plant can bend as the plant moved int he wind

Question 33

What is transpiration

Answer 33

The loss of water in a plant’s leaves

Question 34

Transpiration Stream

Answer 34

The constant flow of water from the roots to the xylem and out if the Leaves

Question 35

How does the water enter the xylem

Answer 35

Water diffuses from the soil into the root hairs by osmosis. Before the water can enter a xylem vessel it must travel from cell to cell till it reaches the centre of the root. Once inside the xylem, the water can be transported through the plant

Question 36

How is water lostfrom leaves

Answer 36

The stomata on the surface of the leaves allows co2 to diffuse in for photosynthesis. Guard cells allow the stomata to open and close When the stomata is open the water evaporates from cells inside the leaf’s air spaces . This creates a concentration gradient between the air inside the leaf and the surrounding air. Water vapour then diffuses out of the leaf into the air.

Question 37

How does light intensity affect the rate of transpiration ?

Answer 37

Stomata open in the light and close in the dark and if u increase the light intensity more water evaporates. The rate of transpiration increases u TIL all the stomata are open. Transpiration is now at its maximum rate

Question 38

How does temperature affect the rate of transpiration ?

Answer 38

If you increase temperature the water evaporates more quickly from the leaf. Diffusion of water vapour our of the leaf becomes more rapid. This increase the rate of transpiration

Question 39

How does wind affect the rate of transpiration ?

Answer 39

When Air moves over the surface of the leaf, it moves evaporated water molecules away from the leaf. The faster the wind the fast the rate of transpiration

Question 40

How does humidity affect the rate of transpiration ?

Answer 40

The higher the humidity the more water it contains