organisation

Question 1

how is a sperm cell specialised

Answer 1

• have many mitochondria to provided energy for their journey
• tail to propel sperm to fertilise egg
• acrosome that contains enzymes to penetrate outer layer of egg
• a nucleus containing one set of genetic material

Question 2

how is phloem specialised

Answer 2

• end walls of cell allow sugars through but support tube
• cells arranged end to end in tubes

Question 3

what’s an enzyme

Answer 3

biological catalyst - they speed up chemical reactions in living organisms

Question 4

what are enzymes properties

Answer 4

• all large properties
• have a active site
• each enzyme catalysed a specific reaction
• work best at a specific temp and pH called their optimum

Question 5

why does a enzyme denature and what does that mean

Answer 5

due to high temp and extremes of pH it means the substrate can no longer fit into the enzymes active site so can’t break down food

Question 6

where are amylase made and what do they break down

Answer 6

salivary glands and pancreas break down starch -> maltose

Question 7

where are protease made and what do they break down

Answer 7

made in stomach, pancreas and small intestine
break down protein’s into amino acids

Question 8

where are lipase made and what do they break down

Answer 8

produce in pancreas and small intestine break down fats in to glycerol

Question 9

what does bile do

Answer 9

produce in liver
neutralised HCL acid from stomach emulsifies fat to form small droplets increasing surface area for enzymes to act on

Question 10

what does plasma transport

Answer 10

various chemical substance around body such as products of digestion antibodies urea and co2

Question 11

properties of red blood cells

Answer 11

-contain haemoglobin which binds to oxygen to transport it to the lungs and body
- don’t contain nuclear so more room for haemoglobin
- very small so can fit through tiny capillaries
- shaped like bioconcave discs giving them large surface area

Question 12

properties of white blood cells

Answer 12

• help protect body against infection
• can change shape so can squeeze out of blood vessels into the tissue or surround antigens

Question 13

what do platelets do

Answer 13

fragment of cells which collect at wounds and clot

Question 14

properties of arteries

Answer 14

• take blood away from heart to body
• thick walls made of elastic and muscle fibres to resist high pressure of blood

Question 15

properties of veins

Answer 15

• take blood from
  the organs back to the heart
• thinner walls and valves to prevent back low as pressure is lower

Question 16

properties of capillaries

Answer 16

• join ateries to veined
• narrow vessels with walls that are one cell thick to help which gaseous exchange

Question 17

what’s are double circulatory system

Question 18

definition of double circulatory system

Answer 18

blood is pumped to the lungs by
right side of the heart
and
blood is pumped to the body by the left side of the heart

Question 19

route of blood around the heart

Answer 19

Blood comes into the right atrium from the body,
moves into the right ventricle and is pushed into the pulmonary arteries in the lungs.
After picking up oxygen, the blood travels back to the heart through the pulmonary veins
into the left atrium, to the left ventricle and out to the body’s through the aorta

Question 20

what do valves do

Answer 20

stop back flow and make sure blood flows in the right direction

Question 21

what acts as a pacemaker

Answer 21

a group of cell located in the right atrium that control the natural resting heart rate

Question 22

what are the advantages and disadvantages of a mechanical valve

Answer 22

• longer lasting or more durable
•less likely to need replacing (within 6 years
• blood clots (on the brain) are more likely (after surgery)
• patient has to take anti-clotting medication (for the rest of their
lives)
• if medication not taken (correctly), clots can lead to blood clots
on brain / heart attack
• medication can lead to excessive bleeding (after injury)
• survival rate at 5 years is slightly higher for mechanical valve
• lower percentage of deaths due to heart-related problems
• readily available
• little waiting time

Question 23

what are advantages and disadvantages of a biological valve

Answer 23

• no additional medication required
• ethical issues surrounding use of animal tissue
• valve may harden
• more likely to need further operation or another new valve
• more likely to be rejected
• more likely to need (immuno-suppressant) medication
• readily available
• little wait time

Question 24

how are alveoli adapted to carry out gaseous exchange

Answer 24

• large moist surface area
• rich in blood supply
• very close to capillaries
• one cell thick

Question 25

Describe how the small intestine is adapted for efficient absorption

Answer 25

capillaries are thin one cell thick for shorter diffusion distance (small intestine is) very long, increasing time (for absorption) good / efficient blood supply to maintain concentration gradient cells have many mitochondria for (aerobic) respiration for active transport or cells have many mitochondria for energy release for villi provide a large surface area

Question 26

what is coronary heart disease and how is it treated

Answer 26

later of fatty material build up inside conorary ateries treatments include stents to keep artery open and statin to reduce blood cholesterol

Question 27

what are the two types of tumours

Answer 27

benign - do not spread and are usually contained in a membrane malignant - do spread to part of the body to form secondary tumours

Question 28

properties of phloem

Answer 28

- transport glucose + amino acids around plant - living tissue - elongated cells with pores between - substance travel both ways - cells have cytoplasm

Question 29

what are the 4 organs on a plant

Answer 29

root stem flowers leaves

Question 30

how do u calculate the number of stomata on a leaf

Answer 30

1/area x mean of stomata

Question 31

what are the 4 steps of transpiration

Answer 31

1- guard cells flaccid stomata close 2- sunlight causes potassium ions to move into guard cells 3- guard cells concentrated , outside is dilute so water moves in 4- guard cells now turgid stomata open

Question 32

what 3 factors increase transportation

Answer 32

high temp - diffuse faster windy ( move water so steeper conc gradient) low humidity (diffuse faster) sun ( stomata open)

Question 33

what are lipids made from

Answer 33

glycogen formed with 3 fatty acids

Question 34

what are the properties of xylem

Answer 34

- dead tissue - transport water + minerals around plant - substance only travel 1 way - no cytoplasm - hollow cells

Question 35

what’s the spongy mesophyll tissue

Answer 35

air space so gases can diffuse into and out the leaf

Question 36

whats the function of the epidermal tissue

Answer 36

transparent cell that protects leaf

Question 37

what 3 types of defences do plants have

Answer 37

physical mechanical chemical

Question 38

what’s the function of the palisade tissue

Answer 38

to absorbs light used for photosynthesis

Question 39

where are digestive enzymes produced

Answer 39

in lining of gut produced by specialised cells in the glands

Question 40

what’s transpiration

Answer 40

where water evaporates threw the leaves g

Question 41

what’s translocation

Answer 41

Translocation is the movement of sugar produced in photosynthesis to all other parts of the plant for respiration

Question 42

what does heamoglobin do

Answer 42

binds to oxygen to transport it from lungs to tissues and cells

Question 43

what are the 2 types of tumours

Answer 43

benign - doenst spread contains membrane malignant - spread in blood to different parts of the body to turn into secondary tumours