Bioenergetics Flashcards

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1
Q

State the balanced symbol equation for photosynthesis

A

6 CO2 + 6 H2O → C6H12O6 + 6 O2

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2
Q

State the word equation for photosynthesis

A

light

carbon dioxide + water → glucose + oxygen

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3
Q

Name 5 uses of glucose (for plants)

A
  • Respiration
  • Making Cellulose
  • Making Amino Acids
  • Stored as Oils or Fats
  • Stored as Starch
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4
Q

How glucose is used for respiration (in plants)?

A

Respiration transfers energy from glucose = enables plant to convert rest of glucose into other useful substances

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5
Q

How glucose is used to make cellulose (in plants)?

A

Glucose is converted into cellulose for making strong plant cell walls

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6
Q

How glucose is stored as oils or fats (in plants)?

A

Glucose is turned to lipids (fats & oils) for storing in seed

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7
Q

How glucose is used to make amino acids (in plants)?

A

Glucose combined with nitrate ions (from soil) to make amino acids = made then into proteins

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8
Q

Where is starch stored and why is it stored?

A

Glucose turned into starch and stored in roots, stems & leaves, ready for use when photosynthesis isn’t happening (like in winter)

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9
Q

Why is starch better for storing than glucose?

A

Because starch is insoluble - cell with lots of glucose would draw in loads of water and swell up

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10
Q

What is a limiting factor?

A

Is something that can stop photosynthesis from happening any

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11
Q

Name 4 things the rate of photosynthesis is affected by?

A
  • Temperature
  • Intensity of light
  • Concentration of carbon dioxide
  • Chlorophyll
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12
Q

How can amount of chlorophyll in plant be affected?

A

Can be affect by disease or environmental stress (lack of nutrients)

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13
Q

How does amount of chlorophyll affect the rate of photosynthesis?

A

If chloroplasts are damaged or don’t make enough chlorophyll (e.g. due to disease), means rate of photosynthesis decreases as they can’t absorb as much light

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14
Q

In winter, what is usually the limiting factor?

A

Temperature

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15
Q

At night, what is usually the limiting factor?

A

Light

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16
Q

When it’s warm enough and bright enough, what is usually the limiting factor?

A

Carbon dioxide

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17
Q

Why does photosynthesis require light?

A

Because it provides energy

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18
Q

As the light level is raised, what happens to the rate of photosynthesis?

A

It increases steadily BUT only up to a certain point

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19
Q

Why might the rate of photosynthesis not increase as the light intensity increases?

A

Because either temperature or CO2 level is a limiting factor

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20
Q

As the CO2 level is raised, what happens to the rate of photosynthesis?

A

It increases steadily BUT only up to a certain point

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21
Q

Why does the temperature affect the rate of photosynthesis?

A

Because it affects enzymes involved

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22
Q

What does it mean if the limiting factor is temperature?

A

Means the temperature is too low

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23
Q

Why does increasing the temperature make the rate of photosynthesis increases?

A

Because the collisions between enzymes and substrates occur more frequently

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24
Q

What happens to the rate of photosynthesis when a plant gets too hot and why?

A

Enzymes become denatured causing photosynthesis to stop completely

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25
Q

Why is respiration important?

A

It transfers energy that cells needs to do everything - this energy is used for all living processes

26
Q

What is respiration?

A

Process of transferring energy from glucose, which goes on in every cell

27
Q

Name 3 things respiration transfers energy for?

A
  1. To build up larger molecules from smaller ones (like proteins from amino acids)
  2. In animals it’s used to allow the muscles to contract (so they move about)
  3. In mammals & birds the energy is used to keep their body temperature steady in colder surroundings
28
Q

What is aerobic respiration?

A

Respiration using oxygen - most efficient way to transfer energy from glucose

29
Q

State the word equation for aerobic respiration

A

glucose + oxygen → carbon dioxide + water

30
Q

State balanced symbol equation for aerobic respiration

A

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

31
Q

When is anaerobic respiration is used?

A

If there’s not enough oxygen

32
Q

Why doesn’t anaerobic reposition transfer nearly as much energy as aerobic respiration?

A

Because glucose isn’t fully oxidised (doesn’t combine with oxygen)

33
Q

What is anaerobic respiration?

A

It’s the incomplete breakdown of glucose, making lactic acid

34
Q

State the word equation for anaerobic respiration (occurs in animals)

A

glucose → lactic acid

35
Q

When is anaerobic respiration useful?

A

Only useful in emergencies

36
Q

When plants and yeast cells respire without oxygen, what do they produce?

A

They produce ethanol and carbon dioxide (instead of lactic acid)

37
Q

What is anaerobic respiration called in yeast cells?

A

fermentation

38
Q

In bread-making, what makes bread rise?

A

The carbon dioxide from fermentation

39
Q

In beer and wine-making, what produces alcohol?

A

The fermentation process

40
Q

State the word equation for anaerobic respiration that occurs in plants and yeast cells

A

glucose → ethanol + carbon dioxide

41
Q

Why do muscles need energy from respiration?

A

To contact

42
Q

Name 3 things that happens when you exercise (to increase respiration)

A
  • Breathing rate increases
  • Breath volume increase
  • Heart rate increases
43
Q

Why does your breathing rate and breath volume increases when you exercise?

A

To get more oxygen into blood

44
Q

Why does your heart rate increases when you exercise?

A

To get this oxygenated blood around body faster & also removes CO2 more quickly at same time

45
Q

When you do really vigorous exercise (e.g. Sprinting), what happens?

A

Your body can’t supply oxygen to your muscles quickly enough so they start respiring anaerobically

46
Q

Why anaerobic respiration not the best way transfer energy from glucose?

A

Because lactic acid builds up in muscles which gets painful

47
Q

After resorting to anaerobic respiration, when you stop exercising you’ll have an …

A

“oxygen debt”`

48
Q

What is an oxygen debt?

A

Amount of extra oxygen your body needs to react with build up lactic acid and remove it from cells

49
Q

When oxygen reacts with lactic acid, what is formed?

A

(Harmless) CO2 and water

50
Q

Why do you have to keep breathing hard for a while after you stop exercising?

A

To get more oxygen into your blood (transported to muscle cells)

51
Q

When does your pulse and breathing rate stay high?

A

Whilst there’s high levels of lactic acid and CO2

52
Q

What the other way your body copes with high levels of lactic acid?

A

Blood that enters your muscles transports lactic acid to liver. In liver, lactic acid is converted back to glucose.

53
Q

How can you increase carbon dioxide levels in a greenhouse?

A

Using paraffin heater = heats & makes CO2 as by-product

54
Q

What’s the benefit of keeping plants in a greenhouse?

A

Keep free from pests & diseases

55
Q

Why does a fitter person have a lower heart rate?

A

A fitter person’s heart is stronger → can pump more blood in each beat = doesn’t have to work as hard

56
Q

Name 2 short-term internal effects of exercise

A
  • Glucagon turns glycogen back into glucose for respiration
  • Vasodilation
57
Q

Define heart rate

A

Beats per min

58
Q

Define cardiac output

A

Vol. of blood pumped in a minute

59
Q

Define stroke volume

A

Vol. of blood in one beat

60
Q

How do you calculate cardiac output

A

Stroke Volume x Heart Rate