2 Transport Flashcards

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1
Q

What organism can rely on diffusion for movement of substances in and out of cells?

A

simple unicellular organism
large surface are to volume ratio so short diffusion distance

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2
Q

Why do multicellular organisms need a transport system?

A

have small surface area to volume ratio
transport system needed to deliver nutrients, oxygen and other substances to all body cells and take away waste products
simple diffusion too slow

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3
Q

What does the phloem transport?

A

sucrose (converted from sugar made in photosynthesis) and amino acids - from leaves (where they’re made) to the growing points (e.g. tips of the shoot and flowers) or storage areas (roots or bulbs)

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4
Q

What is the phloem made up of?

A

tubes formed by living cells arranged end to end

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5
Q

Moving sucrose and amino acids around the plant requires…

A

energy
this is called translocation

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6
Q

What does the xylem do?

A

transports water (and minerals) to the leaf

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7
Q

How do the xylem transport water and mineral ions from root to leaf?

A

Water molecules move through the plant upwards in a transpiration stream

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8
Q

What is the xylem made up of?

A

thick walled dead cells containing no cytoplasm
cell walls contain lignin - waterproof

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9
Q

What are nitrate ions needed for in plants?

A

to make amino acids and proteins

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10
Q

What are magnesium ions needed for in plants?

A

to make chlorophyll

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11
Q

PAPER 2 How is water absorbed by root hair cells?

A

Root hair cells are elongated cells which give the plants a big surface area for absorbing water from the soil.
Water is taken in via osmosis

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12
Q

PAPER 2 What is transpiration?

A

The evaporation of water from the stomata

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13
Q

PAPER 2 What factors affect the rate of transpiration?

A

Light intensity
Temperature
Wind speed
Humidity

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14
Q

PAPER 2 How does light intensity affect the rate of transpiration?

A

brighter light, greater transpiration rate
stomata close as it gets darker as photosynthesis can’t happen. When stomata are closed, little water can escape

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15
Q

PAPER 2 How does temperature affect the rate of transpiration?

A

warmer = faster transpiration
particles have more energy to evaporate and diffuse out of the stomata

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16
Q

PAPER 2 How does wind speed affect the rate of transpiration?

A

higher wind speed around leaf, greater transpiration rate
water vapour is swept away, maintaining a low concentration of water in air around leaf. Diffusion happens quickly, from area of high to low concentration

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17
Q

PAPER 2 How does humidity affect the rate of transpiration?

A

drier air, faster transpiration
if air is humid, there is lots of water surrounding plant so little difference between inside and outside of plant. Diffusion happens slowly/not at all

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18
Q

PAPER 2 Use CORMS to describe an investigation of the role of environmental factors in determining the rate of transpiration from a leafy shoot.

A

Potometers measure the uptake of water and estimate transpiration
Change - conditions ( vaseline, no vaseline, wind, no wind )
Organism - plant (cut shoot at slant to increase SA and underwater to prevent air from entering xylem )
Repeat - 3 times
Measure - distance bubble moves
Same - species (laurel)

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19
Q

What is the composition of blood?

A

Plasma
Red blood cells
Platelets
White blood cells

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20
Q

What is the plasma?

A

straw coloured liquid
transports blood cells and other substances
e.g. dissolved nutrients such as glucose and amino acids; dissolved waste products including urea and carbon dioxide; hormones; proteins; heat energy

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21
Q

What are red blood cells?

A

transport oxygen, bound to haemoglobin

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22
Q

What are platelets?

A

cell fragments
release chemicals when blood is exposed to air, cause soluble fibrinogen to be converted to insoluble fibrin

23
Q

What are white blood cells?

A

fight disease

24
Q

What adaptations of red blood cells make them suited to their job?

A

haemoglobin to bind oxygen forming oxyhaemoglobin - transports oxygen to respiring cells
no nucleus - more haemoglobin can be packed into cell
biconcave - increases surface area to volume ratio and decreases distance to centre of cell, increasing diffusion rate

25
Q

PAPER 2 How do platelets cause blood clotting?

A

if exposed to oxygen (because of cut) release chemicals which cause soluble plasma protein fibrinogen to be changed into insoluble fibrin
Fibrin forms network of fibres across cut, trapping platelets and red blood cells, forming clot, or scab

26
Q

PAPER 2 What does blood clotting prevent?

A

further loss of blood
also acts as barrier to prevent entry of pathogens (microorganisms)

27
Q

What is the structure of the heart?

A

two atria
two ventricles
right side = deoxygenated
left side = oxygenated

28
Q

What are the sides of the heart separated by?

A

septum

29
Q

What side wall is thicker than the other in the heart?

A

left ventricle wall thicker than right to allow it to pump blood at higher pressure so blood can travel round whole body

30
Q

How does the heart function?

A

two sides contract and relax at same time to pump blood.
atria contract, emptying blood into ventricles
ventricles contract pushing blood into arteries
valves close to ensure blood flows in right direction

31
Q

How does heart rate change during exercise?

A

average = 70bpm
exercise = muscles need more glucose and oxygen for aerobic respiration
HR increases so more blood travels to muscles

32
Q

What are changes in heart rate controlled by?

A

nerve impulses from medulla in brain

33
Q

How does the medulla notice need for change in heart rate?

A

muscles produce more carbon dioxide in aerobic respiration
sensors in aorta detect increase
send nerve impulse to medulla
medulla responds by sending nerve impulses along accelerator nerve which increase heart rate
more blood supplied to meet demand of increased aerobic respiration

34
Q

How is heart rate decreased?

A

decelerator nerve send electrical impulses to decrease heart rate at rest

35
Q

Why else would heart rate increase?

A

when stressed, angry or afraid
triggered by secretion of adrenaline

36
Q

What blood vessels go in and out of the liver and gut?

A

into liver - hepatic artery
into gut - mesenteric artery
Into liver/out of gut - hepatic portal vein
out of liver - hepatic vein

37
Q

what blood vessels go in and out of the kidneys?

A

into - renal artery
out of - renal vein

38
Q

What is the general structure of the circulatory system?

A

lungs
heart
liver
gut
kidneys
other organs

39
Q

What are the characteristics of an artery?

A

thick elastic muscular wall
small lumen
can stretch and recoil to keep blood flowing at high pressure
control blood flow by dilating and constricting

40
Q

What are the characteristics of a vein?

A

Thin elastic muscular wall
large lumen
semilunar valves - prevent back flow
low pressure so thick wall not needed

40
Q

What are the characteristics of a capillary?

A

Wall one cell thick - short diffusion distance of substance from blood into tissue

41
Q

What are the coronary arteries?

A

supply heart muscle with blood - glucose and oxygen for aerobic respiration, and removes carbon dioxide

42
Q

What causes coronary heart disease?

A

Saturated fats in diet cause fatty deposits to build up in artery walls.
Narrows lumen, restricting blood flow to heart muscles - receive less oxygen and glucose for aerobic respiration so anaerobic respiration increases
Lactic acid builds up, poisoning heart muscle cells causing heart attacks

43
Q

What factors increase the risk of CHD?

A

Diet - lots of saturated fats increases blood cholesterol and increases risk of fatty deposits
Lots of salt in diet increase risk of high BP

Smoking- increases BP and increase risk of fatty deposits forming

High BP - damages artery lining and increase risk of fatty deposits forming

Lack of exercise - cause high BP

44
Q

What is an antigen?

A

foreign proteins on outside of pathogens which cause an immune response

45
Q

What are the two main types of white blood cells?

A

Phagocytes
Lymphocytes

46
Q

What do phagocytes do?

A

Engulf and digest pathogens using digestive enzymes:
recognises pathogen
engulfs pathogen in process known as phagocytosis
lysozymes containing enzymes move towards pathogen
enzymes break down pathogen
useful material absorbed
waste products removed from phagocyte

47
Q

What do lymphocytes do?

A

Produce antibodies (Y shaped protein), which bind specifically to antigens and neutralise pathogen:
Detect antigens
Identifies correct antibody to make, complementary to pathogen’s antigen
Release large number of correct antibody
Pathogens clump resulting in death or antibodies trigger phagocytes
Create memory cells - organisms build immunity to certain diseases

48
Q

How do white blood cells combat toxins?

A

some antibodies specialised to combat toxins (anti-toxins) - chemicals released by pathogen which cause cell damage

49
Q

PAPER 2 What does a vaccine contain?

A

weakened or dead pathogens

50
Q

PAPER 2 What happens in your immune system when you have a vaccination?

A

lymphocytes produce specific antibodies which neutralise pathogen, and make memory cells
memory cells stay in body for a long time

51
Q

PAPER 2 What happens if you come into contact with the actual pathogen after vaccination?

A

Memory cells react to pathogen quickly - recognise foreign antigen, producing lots of antibodies and quickly
Kills pathogen before we feel ill, preventing infection.
Gained immunity

52
Q

PAPER 2 What is different between primary and secondary immune response?

A

secondary = quicker + more antibodies produced