B4 (Organising Animals and Plants)

Question 1

SA:VOL ration in organisms

Answer 1

Larger = smaller
Smaller = larger

Question 2

Main functions of blood

Answer 2

• protect body from pathogens
• carry oxygen to muscles
• carry carbon dioxide away from body cells
• carry nutrients (glucose/minerals) to cells
• carry waste products to be excreted

Question 3

Blood Plasma

Answer 3

• yellow liquid carries blood
• UREA: formed in kidneys breaks down proteins for excretion
• small products of digestion

Question 4

Components of blood

Answer 4

• plasma
• carries the red, white blood cells and platelets
• carries between 4.7 and 5 litres of blood

Question 5

Red Blood cells (pick up oxygen) adaptations

Answer 5

• biconcave disks increase SA:VOL ratio

- haemoglobin binds with oxygen (no nucleus=more space)

Question 6

White blood cells

Answer 6

• bigger than red but less
• antibodies protects against micro-organisms (lymphocytes)
• (phagocytes) invade / digest bacteria

Question 7

Platelets

Answer 7

• small fragment of cells (no nucleus)
• blood clot a wound
• network of protein fibres capture red blood cells to form the scab to protect against bacteria through the cell

Question 8

Arteris

Answer 8

• small lumen

- thick walls which stretch to deal with high pressure, oxygenated blood

Question 9

Veins

Answer 9

• large lumen
• thin walls because lower pressure
• valves stop back-flow as blood carried towards the heart

Question 10

Capillaries

Answer 10

• tiny vessel, one cell thick
• large network linking arteries/ veins
• small walls means oxygen and glucose can diffuse easier
• carbon-dioxide pass easily out

Question 11

Left side of the heart

Answer 11

• pulmonary artery (to the lungs)
• vena cava (from body)
• right atrium
• right ventricle

Question 12

Right side of the heart

Answer 12

• aorta (to body)
• pulmonary vein (from lungs)
• left atrium
• left ventricle

Question 13

Stages of the blood circulation

Answer 13

• deoxygenated blood entres right atrium through vena cava, whilst oxygenated blood enters left atrium through the pulmonary veins
• deoxygenated blood travels through valve to right ventricle and leaves through pulmonary artery, whilst oxygenated blood travels through valve to left ventricle out the aorta
• double circulatory system

Question 14

Stents

Answer 14

Metal grids which expand to get rid of the plaque on the walls of the artery

Question 15

Statins (Adv/Dis)

Answer 15

• drugs to reduce rate of the fatty acids forming
  ADV: reduce risk of strokes, coronary heart disease and heart attacks
  DIS: side effects including headache, memory loss , liver damage

Question 16

Leaky valves

Answer 16

Heart valves can become very stiff and stop functioning over time due to the high pressure of blood

Question 17

False heart valves

Answer 17

• titanium and polymers can replace the faulty valves
• mechanical valves you have to take medicine for the rest of your life to stop blood clot
• biological valves work very well but for only 12-15 years

Question 18

Pacemakers

Answer 18

• used if not enough beats or too many
• two wires which send electrical impulses to simulate the rhythm properly
• some could help your heart beat faster whilst exercising

Question 19

Artificial Hearts (ADV/DIS)

Answer 19

ADV: 
- puts diseased hearts at rest so they can recover
- removes strain off circulation
DIS:
- donor has to have tissue match
- a lot of machinery
- very exspensive

Question 20

Trachea (structure + function)

Answer 20

• windpipe with small rings
• connects the nose to the broncho to allow air flow for gas exchange
• rings keep the trachea open

Question 21

Bronchi (Structure + Function)

Answer 21

• shuttle/ tube leading from the trachea to alveoli

- oxygen is forced through to the lungs, whilst carbon dioxide leaves through here

Question 22

Alveoli (Structure + function)

Answer 22

• tiny sacs

- gas exchange occurs here and the oxygen diffuses through the air

Question 23

4 adaptations of the alveoli

Answer 23

1) increased surface area, more room for diffusion
2) thin wall, diffusion is quicker less to travel
3) blood supply, bigger concentration gradient making it quicker
4) moist layer, gases dissolve quicker

Question 24

As you breathe in…

Answer 24

• high pressure lungs
• increased volume in chest, lower pressure
• ribs moves out and diaphragm flatterns

Question 25

As you breathe out…

Answer 25

• high pressure chest, air forced out
• decreased volume means high pressure in chest
• ribs falls and diaphragm move up

Question 26

Upper epidermis (Structure + function)

Answer 26

• one cell thick

- waxy layer makes it water proof

Question 27

Paliside mesophyll (Structure + function)

Answer 27

• cylindrical shape

- helps sunlight penetrate contains chloroplasts

Question 28

Spongy Mesophyll (Structure + function)

Answer 28

• irregular shapes like sponges

- less chloroplasts less intensity

Question 29

Lower epidermis (Structure + function)

Answer 29

• one cell thick with pores

- pores called stomata made up of guard cells

Question 30

Guard cells (Structure + function)

Answer 30

• small pocket

- open and close for photosynthesis/ transpiration

Question 31

Translocation

Answer 31

• movement of dissolved sugars (phloem)

- moving from the source (lead) to the rest of the plant

Question 32

Transpiration stream

Answer 32

• movement of water from the roots to the stem then out the leaves
• 90% of water will be lost through the stomata
• transpiration is JUST when the water leaves through the stomata

Question 33

4 factors effecting tranpiratiom

Answer 33

• brighter light opens stomata
• temperature increases as evaporation rates increase
• wind speed increases as water vapour around the leaf moves away
• as humidity increased it decreases as high pressure outside lead

Question 34

Open Stomata

Answer 34

• guard cells turgid as the water squeezes the stomata

Question 35

Closed stomata

Answer 35

• guard cells are flaccid meaning less water so the opening releases