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gcse biology > b4 - organising animals and plants > Flashcards

b4 - organising animals and plants Flashcards

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1
Q

what does the human circulatory system consist of?

A

the blood, blood vessels and heart

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2
Q

what does liquid plasma contain?

A

red blood cells, white blood cells and platelets

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3
Q

give three examples of substances blood transports

A
  • carbon dioxide from organs to lungs
  • soluble products of digestions from small intestine to other organs
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4
Q

define red blood cells structure

A
  • biconcave discs
  • no nucleus
  • contain red pigment: haemoglobin
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5
Q

define red blood cells function?

A
  • use their haemoglobin to combine with oxygen, which forms oxyhaemoglobin in the lungs
  • carry the oxygen to all organs, where the oxyhaemoglobin splits back into haemoglobin and oxygen
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6
Q

define white blood cells structure

A
  • have a nucleus
  • form part of body’s defence system against microorganisms
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7
Q

define white blood cells function?

A
  • some produce antibodies
  • some produce antitoxins
  • some engulf microorganisms
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8
Q

define platelets structure

A
  • small fragments of cells
  • do not have a nucleus
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9
Q

define platelets function

A

help the blood to clot at the site of a wound

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10
Q

define blood clotting

A

series of enzyme controlled reactions

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11
Q

what does the final reaction of blood clotting cause?

A
  • causes fibrinogen to change into fibrin
  • fibrin forms a network of fibres that trap blood cells and form a clot
  • the clot dries and forms a scab
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12
Q

define arteries function and structure

A
  • carry blood away from heart
  • have thick walls containing muscle and elastic tissue
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13
Q

define veins function and structure

A
  • carry blood towards heart
  • have thinner walls that arteries
  • have valves along their length to prevent backflow of blood
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14
Q

define capillaries

A
  • narrow, thin-walled vessels
  • carry blood through organs
  • allow exchange of substances with all the living cells in the body
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15
Q

define double circulation

A
  • in humans and other mammals
  • one transport system carries blood from your heart to your lungs and back again
  • the other transport system carries blood from your heart to all other organs of your body and back again
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16
Q

define the structure of the heart

A
  • muscular organ made up of two pumps held together
  • has four chambers left atrium, right atrium, left ventricle, right ventricle
  • atria are separated from ventricles by valves
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17
Q

what are the four main blood vessels that enter and leave the heart?

A

1) vena cava brings in deoxygenated blood from the body
2) blood then passes from heart to lungs (where it collects oxygen) in pulmonary artery
3) oxygenated blood passes from lungs to heart in pulmonary vein
4) blood then pumped from heart to body in aorta

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18
Q

define pattern of blood flow through the heart

A
  • first blood enters left atrium then right atrium
  • atria contract and blood forced into ventricles
  • ventricles contract and force blood out of heart
  • valves stop backflow of blood into atria when ventricles contract
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19
Q

why does the left side of the heart have a thicker muscular wall than the right side?

A

left ventricle pumps blood around entire body so needs to provide greater force, right ventricle only pumps blood to lungs

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20
Q

how does coronary heart disease occur?

A

when coronary arteries become blocked or narrower due to buildup of fatty material inside

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21
Q

what do coronary arteries do?

A

heart muscles provided with deoxygenated blood via coronary arteries

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22
Q

what does a stent do?

A

opens up arteries, allowing blood to deliver nutrients and oxygen to heart muscle again

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23
Q

what is bypass surgery?

A

used to replace damaged coronary arteries with lengths of vein

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24
Q

what are statins?

A

prescribed to lower cholesterol, which in turn reduces fatty buildup in arteries

25
Q

how can leaky valves be treated?

A
  • leaky valves mean blood could flow in wrong direction
  • artificial or animal valves can be inserted to replace damaged valves
26
Q

define pacemaker

A

group of cells that controls natural resting heart rate (about 70 beats per minute for adults)

27
Q

where is the natural pacemaker located?

A

right atrium

28
Q

what could happen if natural pacemaker does not work properly and how can this be treated?

A
  • heart rhythm can become irregular
  • artificial pacemaker is an electrical device that can be fitted into chest to correct irregularities
29
Q

how could someone with a weak or diseased heart be treated?

A

may require a transplant, donors are not always available so artificial hearts are being developed

30
Q

give the uses of artificial hearts and one disadvantage

A
  • keep patients alive while waiting for a heart transplant
  • allow heart to rest as aid of recovery
  • disadvantage is that a person would need drugs to prevent blood from clotting
31
Q

how does a natural pacemaker maintain heart rate?

A

generate electrical signals that spread to the heart’s muscle cells, making the heart contract

32
Q

what do lungs contain and where are they situated?

A
  • contain exchange surface of breathing system
  • situated in thorax, inside ribcage and above diaphragm, which separates lungs from abdomen
33
Q

what happens when you breathe in?

A
  • intercostal muscles, between ribs, contract, moving ribcage up and out
  • muscles of the diaphragm contract and diaphragm flattens
  • volume of thorax increases
  • pressure in thorax decreases and air is drawn into your lungs
34
Q

what happens when you breathe out?

A
  • intercostal muscles of ribcage and diaphragm relax
  • ribcage moves down and in and the diaphragm becomes domed
  • volume of thorax decreases
  • pressure increases and air is forces out
35
Q

what is absorbed into lungs and what is removed in from air?

A
  • oxygen is absorbed from the air into the blood in the lungs
  • carbon dioxide is removed from the blood to the air
36
Q

what do efficient exchange surfaces have?

A
  • large surface area
  • thin walls
  • short diffusion path
  • efficient transport system
37
Q

how is gaseous exchange surface in lungs increased?

A

surface area increased by the alveoli

38
Q

what do alveoli have?

A
  • large surface area
  • thin walls
  • good blood supply
39
Q

why are the lungs ventilated?

A

to maintain a steep concentration gradient

40
Q

what do oxygen and carbon dioxide do in relation to capillaries?

A
  • oxygen diffuses into the many capillaries surrounding the alveoli
  • carbon dioxide diffuses back out into the lungs to be breathed out
41
Q

give five examples of plant tissues

A

1) epidermal tissue, covers plant
2) palisade mesophyll, many chloroplasts, can photosynthesise
3) spongy mesophyll, some chloroplasts, many air spaces between cells, large sa for diffusion of gases
4) xylem, transports water and dissolved mineral ions from root to rest of plant
5) phloem, transports dissolved food substances from leaves to rest of plant

42
Q

define plant organs

A
  • each has its own function e.g: stems, roots, leaves
  • plant organs form a plant organ system to transport substances around the plant
43
Q

define translocation

A

phloem tissues carry dissolved sugars from leaves to rest of plant including growing regions and storage organs

44
Q

why do cells in plant need sugar produced in photosynthesis?

A

needed for respiration

45
Q

what are sugar and mineral ions needed for?

A

growth

46
Q

what is water needed for?

A
  • photosynthesis
  • to support cells, mainly young plants and leaves
47
Q

how can movement of water through xylem be demonstrated?

A
  • place celery stalks in water containing a coloured dye
  • after a few hours slice the stem in several places - you will see coloured circles where water and dye have moved through xylem
48
Q

how do gases diffuse in and out of leaves?

A
  • through tiny holes called stomata
  • size of stomata is controlled by guard cells surrounding them
49
Q

what happens when water gets to the leaves?

A
  • water evaporates from cells in leaf to air spaces between them
  • this water vapour diffuses out of the plant through stomata on leaf surface when stomata are open, this is transpiration
50
Q

define transpiration stream

A

movement of water through plant

51
Q

how can excessive water loss be prevented?

A

guard cells can close stomata

52
Q

how could a plant dehydrate?

A

if rate of evaporation in leaves is greater than rate of water uptake

53
Q

how does temperature affect rate of photosynthesis?

A
  • as temp increases, molecules move faster so more water evaporates and rate of diffusion of water from the leaf also increases
  • as temp increase, rate of photosynthesis increases, more stomata are open
54
Q

how does humidity affect rate of photosynthesis?

A

rate of diffusion water from the leaf is faster in dry air than in damp air

55
Q

how does airflow affect rate of photosynthesis?

A

windy conditions increase rate of evaporation and keep a steep concentration gradient between inside and outside of leaf by blowing away water vapour

56
Q

how does light intensity affect photosynthesis?

A

more light means there will be an increase in the rate of photosynthesis

57
Q

how does an increase of photosynthesis increase transpiration?

A

increases the opening of stomata to let carbon dioxide into the leaf

58
Q

how are plants adapted to control water loss?

A

1) waxy cuticle, thick and shiny in hot environments
2) most stomata are on underside of leaf
3) wilting of whole plant, leaves collapse and surface area reduced
4) stomata can close, stops photosynthesis but prevents more water loss and further wilting

gcse biology (17 decks)

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