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biology > bioenergetics (T4) > Flashcards

bioenergetics (T4) Flashcards

1
Q

what cellular structures are specific to plants and not animals

A

chloroplasts, vacuole, cell wall

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2
Q

function of a root hair cell

A

absorb water and dissolve mineral ions from the soil

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3
Q

adaptations of root hair cell

A
  • special shape with long cytoplasmic extension (root hair)
  • large permanent vacuole
  • many mitochondria
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4
Q

how do the adaptations of a root hair cell help

A
  • gives a large SA for more efficient absorption
  • store large amounts of water to help maintain conc. gradient
  • allow lots of respiration to release energy for the active transport of minerals
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5
Q

function of a palisade cell

A

maximum photosynthesis

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6
Q

adaptations of a palisade cell

A
  • lots of chloroplasts
  • rectangular shape
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7
Q

how do the adaptations of a palisade cell help

A
  • more photosynthesis able to occur
  • you can get lots of cells near the top of the leaf for maximum light
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8
Q

function of flower

A

attract pollinators for reproduction

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9
Q

role of fruit in plant

A

seed dispersal

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10
Q

function of stem

A
  • transport substances
  • support leaves + flowers
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11
Q

function of leaf

A

photosynthesis

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12
Q

function of roots

A
  • takes up water + minerals from the soil
  • anchors plant in the ground
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13
Q

what are the two types of plant tissue

A

xylem and phloem

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14
Q

what does xylem transport

A

minerals and water

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15
Q

what is the direction of flow in xylem

A

one-way (roots -> leaves)

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16
Q

what type of cells are xylem made of

A

dead cells

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17
Q

describe the structure of a xylem cell

A
  • cells have no end walls so form long hollow tubes
  • walls are strengthened with lignin which makes it tough and water-proof
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18
Q

what does phloem transport

A

sugar

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19
Q

what is the direction of flow in phloem

A

two-way ( where it’s made => where its needed) translocation

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20
Q

what type of cells are phloem made of

A

living cells

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21
Q

describe the structure of a phloem cell

A
  • perforated end walls
  • companion cells with lots of mitochondria to keep the phloem cells alive and release energy for the movement of sugar
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22
Q

how are leaves adapted for photosynthesis

A
  • broad and flat to give a large SA to absorb sunlight
  • thin so carbon dioxide can easily diffuse through to the palisade cells
  • conatin chlorophyll to absorb light energy
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23
Q

what tissues does the leaf organ contain

A
  • epidermis
  • palisade mesophyll
  • spongy mesophyll
  • xylem
  • phloem
  • guard cells
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24
Q

how is epidermal tissue adapted for its function

A

covers the entire plant, waxy cuticle helps reduce water loss

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25
Q

how is palisade mesophyll tissue adapted for its function

A

contains lots of cholorplasts which allows photosynthesis to occur at a rapid rate

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26
Q

how is spongy mesophyll tissue adapted for its function

A

lots of air spaces which allows gases (including O2 and CO2) to diffuse in and out

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27
Q

how is meristem tissue adapted for its function

A

made of stem cells which can differentiate into many differnet cell types allowing the plant to grow.

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28
Q

what is the function of guard cells

A

control the opening and closing of the stomata, dependent on the water content of the plant

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29
Q

how are stomata adapted for their function

A

control of gaseous exchange and water loss from leaf:
* more stomata on the base of the leaf - minimises water loss as this side is cooler and shaded
* have guard cell which control their opening and closing

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30
Q

4 main factors that affect rate of phtotosynthesis

A
  • temperature
  • light intensity
  • CO2 concentration
  • amount of chlorophyll
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31
Q

what factors affect transpiration

A
  • increase in temp.
  • increase in wind sped
  • increase in humidity
  • increase in light intensity
32
Q

how does transpiration work

A
  • water evaporates from the leaf’s surface via the stomata
  • water molecules cohere together - more water is pulled up the xylem in an unbroken column
  • more water is taken up from the soil - creating a continuous transpiration stream
33
Q

how does an increase in temp. affect trasnpiration

A

causes an increase in tranpiration rate
- higher the temp. the more energy the water particles will have therefore they will move faster and evaporate quicker

34
Q

how does an increase in wind speed affect transpiration

A

increase in transpiration rate
- if airflow is poor, water vapour will surround the leaf which would reduce the concentration gradient so less water would evaporate
- high wind speed improves airflow

35
Q

how does an increase in humidity affect transpiration

A

decrease in transpiration rate
- water vapour diffuses more rapidly into dry air than into humid air because the conc. gradient is steeper

36
Q

how does an increase in light intensity affect transpiration

A

increase in transpiration rate
- if light intensity is high,rate of photosynthesis is higher so stomata open more to let in more CO2 so moe water evaporates

37
Q

how can a potometer be used to measure transpiration rate

A
  • measure water uptake of a plant
  • the more water lost in transpiration, the more water a plant will take up
  • measuring the distance the bubble has travelled over a set period of time.
38
Q

what factors affect number of stomata

A
  • type of plant
  • external conditions (light intensity, humidity, co2 conc)
39
Q

how do guard cells and stomata work

A
  • when the stomata need to open, potassium is pumped into the guard cell by active transport
  • this increases the solute concentration and makes water move into the cell by osmosis
  • guard cells swell and due to uneven thickening of their cell wall they become more curved
  • this opens the stomata
  • when the stomata need to close, potassium then water leave the guard cells and they become flaccid (less curved) closing the gap
40
Q

what is photosynthesis

A

the process by which plants synthesise glucose using light energy from the sun.
light energy => chemical energy

41
Q

what type of reaction is photosynthesis

A

endothermic - needs an input of energy from the environment, the input needed is more than the output

42
Q

where does photosynthesis take place

A

within chloroplasts in leaf palisade cells, they contain chlorophyll, a pigment which absorbs light energy

43
Q

what is transpiration

A

evaporation of water vapour from the surface of a plant

44
Q

what is translocation

A

the movement of dissolved sugars from the leaves to other parts of the plant

45
Q

state the equations for photosynthesis (word & symbol)

A

carbon dioxide + water → glucose + oxygen
6CO2 + 6H2O → C6H12O6 + 6O2

46
Q

how can you show that a plant gives off oxygen in photosynthesis

A

using a water plant (e.g. elodea) collect gas bubbles produced during photosynthesis. the gas will relight a glowing splint as it contains oxygen

47
Q

leaf adaptations that maximise rate of photosynthesis

A
  • broad leaves - maximise SA
  • thin leaves - short diffusion distance
  • chlorophyll present - trap light energy
  • veins - transport water to leaves via xylem, remove photosynthesis products via phloem
  • air spaces - allow CO2 in and O2 out
  • guard cells - control opening of stomata for gaseous exchnage and reduce water loss
48
Q

what is glucose converted into?

A
  • starch - storage
  • cellulose - build or strengthen walls
  • nitrates & minerals from the soil (amino acids) - converted to proteins to use as enzymes and for growth and repair
  • fats and oils - growth and energy stage
49
Q

why use starch for storage

A
  • starch can be quickly converted back into glucose for respiration when needed
  • it is insoluble so it does not flow out of the cells it is stored in and it does not affect the water conc -> osmosis
50
Q

how does increase in temperature affect rate of photosynthesis

A

rate of photosynthesis increases at first as the particles have more kinetic energy. however after a certain point the rate decreases as enzymes have become denatured

51
Q

how does increase in light intensity affect rate of photosynthesis

A

rate of photosynthesis increases up to a point. the rate will then stop increasing because there isnt a high enough CO2 conc. or temperature

52
Q

how does increase in CO2 conc. affect rate of photosynthesis

A

rate of photosynthesis increases up to a point. rate then stops increasing because there isnt a high enough light intensity or temperature

53
Q

how does the amount of chlorophyll affect rate of photosynthesis

A

decreasing the amount of chlorophyll (due to a lack of magnesium) decreases the rate of photosynthesis as chlorophyll is needed to absorb light energy

54
Q

what is a limiting factor

A

an environmental factor which can restrict the rate of photosynthesis e.g. light intensity

55
Q

how can farmers use their knowledge of limiting factors to maximise profits

A

they can control temperature, light intensity and CO2 conc. to achieve the fastest possible rate of photosynthesis leading to a greater yield.

56
Q

what equation links light intensity and distance

A

inverse square law:
light intensity ∝ (1/distance2)

57
Q

aerobic respiration equations (word & symbol)

A

C6H12O6 + 6O2 → 6CO2 + 6H2O
glucose + oxygen -> carbon dioxide + water

58
Q

what is aerobic respiration

A

exothermic reaction in which glucose reacts with oxygen to release energy which can be used by cells

59
Q

where does aerobic respiration take place

A

in the mitochondria

60
Q

why do organisms require the energy released in respiration

A
  • building larger molecules from smaller ones
  • muscle contraction
  • maintaining body temperature
  • active transport
61
Q

what is anaerobic respiration

A

exothermic reaction in which glucose is broken down incompletely to release energy when there is an absence of oxygen

62
Q

what is the equation for anaerobic respiration

A

glucose -> lactic acid

63
Q

why is anaerobic respiration less efficient than aerobic respiration

A

glucose is not completely broken down so less energy is transferred

64
Q

why can anaerobic respiration lead to muscle fatigue

A

lactic acid builds up in muscles preventing efficient contraction

65
Q

what is an oxygen debt

A

the amount of oxygen needed to convert lactic acid back to glucose after anaerobic respiration

66
Q

what is fermentation

A

a type of anaerobic respiration that occurs in yeast cells

67
Q

what is the equation for fermentation

A

glucose -> ethanol + carbon dioxide

68
Q

why is the fermentation reaction important

A

it is used in the production of bread and alcoholic drinks

69
Q

what are the differences between aerobic and anaerobic respiration

A
  • aerobic respiration requires oxygen; anaerobic does not
  • aerobic produces CO2 and water; anaerobic produces lactic acid or ethanol + CO2
  • aerobic transfers a greater amount of energy
70
Q

how do muscles store glucose

A

as glycogen

71
Q

what changes take place when muscular activity increases in the body?

A
  • heart rate increases and arteries dilate - increases flow of oxygenated blood to the muscles
  • breathing rate and depth increases - increases the rate of gas exchange
  • stored glycogen is converted back to glucose
72
Q

how is lactic acid transported away from muscles

A

blood flow through muslces transports lactic acid to the liver, where it is oxidised back to glucose

73
Q

what is metabolism

A

the sum of all reactions that take place in a cell or an organism

74
Q

how do cell use the energy transferred by respiration

A

to continuously carry out enzyme-controlled processes which lead to the synthesis of new molecules

75
Q

give examples of metabolic reactions

A
  • glucose into starch/glycogen/cellulose
  • glycerol and fatty acids into lipids
  • glucose and nitrate ions into amino acids
  • photosynthesis
  • respiration
  • breakdown of excess proteins into urea
76
Q

symbol equation for anaerobic respiration in yeast

A

C6H12O6 - > 2C2H5OH + 2CO2

biology (7 decks)

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