B4 - Organising plants and animals

Question 1

name four main components of blood

Answer 1

red blood cells, white blood cells, plasma, platelets

Question 2

function of platelets

Answer 2

form blood clots - prevent loss of blood and stop wounds being infected

Question 3

why is human circulatory system a double circulatory system

Answer 3

• blood passes through the heart twice for every circuit around the body
• deoxygenated blood is pumped from right side of heart to the lungs
• oxygenated blood that returns is pumped from left side to the rest of the body

Question 4

how does structure of artery help with its function

Answer 4

• carries blood away from heart under high pressure
• small lumen
• thick elasticated walls that can stretch - thick muscle to withstand the pressure

Question 5

how does structure of vein relate to its function

Answer 5

• carries blood back to heart at low pressure
• thinner walls because not so much pressure
• has valves to prevent backflow of blood

Question 6

how does structure of capillary relate to its function

Answer 6

• carries blood through organs and tissues
• one cell thick walls to shorten diffusion distance

Question 7

list structures air passes through when breathing in

Answer 7

mouth/nose > trachea > bronchi > bronchioles > alveoli

Question 8

what is the function of red blood cells

Answer 8

bind to oxygen and transport it around the body

Question 9

what is the function of white blood cells

Answer 9

defend body against pathogens

Question 10

what is the function of the plasma

Answer 10

transports blood cells and substances around the body

Question 11

why is a leaf an organ

Answer 11

there are many tissues inside the leaf which work together to perform a function (photosynthesis)

Question 12

how is the upper epidermis adapted for its function

Answer 12

• single layer of transparent cells allow light to pass through
• cells secrete a waxy substance that makes leaves waterproof (waxy cuticle)

Question 13

how is the palisade mesophyll adapted for its function

Answer 13

tightly packed cells with lots of chloroplasts to absorb as much light as possible for photosynthesis

Question 14

how is the spongy mesophyll adapted for its function

Answer 14

air spaces increase the surface area and allow gases to diffuse quickly

Question 15

what is the function of the guard cells

Answer 15

to control the opening and closing of the stomata

Question 16

what is the function of the xylem

Answer 16

transport water and mineral ions from the roots to the rest of the plant

Question 17

give three adaptations of the xylem

Answer 17

• made of dead cells
• no end wall between cells
• walls strengthened by a chemical called lignin to withstand the pressure of the water

Question 18

what is the function of the phloem

Answer 18

transport dissolved sugars from the leaves to the rest of the plant

Question 19

what is the purpose of translocation

Answer 19

transport dissolved sugars from the leaves to other parts of the plant for respiration, growth, and storage

Question 20

define the term transpiration

Answer 20

movement of water from the roots to the leaves through the xylem

Question 21

what is the purpose of transpiration

Answer 21

• provide water to keep cells turgid
• provide water to cells for photosynthesis
• transport mineral ions to leaves

Question 22

name four factors that affect the rate of transpiration

Answer 22

temperature, light intensity, humidity, and wind speed

Question 23

what effect does temperature have of transpiration

Answer 23

higher temperatures increase the rate of transpiration

Question 24

what effect does humidity have of transpiration

Answer 24

higher levels of humidity decreases the rate of transpiration

Question 25

why does increased light intensity increase the rate of transpiration

Answer 25

stomata open wider to let more carbon dioxide into the leaf for photosynthesis

Question 26

what is the function of the stomata

Answer 26

allow diffusion of gases into and out of the plant

Question 27

where are most stomata found

Answer 27

underside of leaves

Question 28

what is the advantage of the plant of having a high number of stomata at this location

Answer 28

reduces the amount of water loss through evaporation