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GCSE Biology > Bioenergetics > Flashcards

Bioenergetics Flashcards

1
Q

Is photosynthesis endothermic or exothermic

A

Endothermic
It requires energy from the sun to happen so takes in light energy

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2
Q

Why is photosynthesis endothermic

A

Takes in energy from the sun (light)

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3
Q

Top 5 uses of glucose by plants

A

Cellular respiration (releases energy)
Converted into insoluble starch for storage
Producing cellulose
Producing amino acids
Producing lipids (fat/ oil)

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4
Q

Top 5 uses of glucose by plants

A

Cellular respiration (releases energy)
Converted into insoluble starch for storage
Producing cellulose
Producing amino acids
Producing lipids (fat/ oil)

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5
Q

Glucose helps produce cellulose. What is the purpose of cellulose

A

Strengthens cell walls

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6
Q

Glucose helps produce amino acids in plants. What are the amino acids needed for

A

Protein synthesis

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7
Q

What else is needed as well as glucose from photosynthesis for plants to produce amino acids

A

Nitrate ions from soil

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8
Q

Glucose can help produce fats in plant. What is the fat used for

A

Future energy source

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9
Q

What is meant by inverse square law

A

As distance of light source from plant increases, light intensity decreases

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10
Q

Relationship between light intensity and distance

A

Light intensity is Inversely proportional to (1 over) the distance squared
E.g if distance doubles then light intensity quarters

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11
Q

What is meant by a limiting factor (of photosynthesis)

A

Anything that limits the rate of a reaction when in short supply

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12
Q

3 main limiting factors of photosynthesis (if you’re asked for a 4th then number of chlorophyll is also one)

A

Light intensity
Temperature
Concentration of carbon dioxide

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13
Q

When drawing a graph to show how limiting factors affect the rate of photosynthesis what goes on each axis

A

Y axis is rate of photosynthesis
X axis is limiting factor (CO2 concentration/ light intensity/ temperature)

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14
Q

Describe how light intensity (limiting factor) affects rate of photosynthesis

A

As light intensity increases so does the rate of photosynthesis
However once the light intensity reaches a certain point something else becomes the limiting factor
Therefore after this certain point rate of photosynthesis will remain at a steady rate even as light intensity keeps increasing

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15
Q

Which 2 limiting factors of photosynthesis have similar graphs

A

CO2 concentration and light intensity

As the factor increases so does rate of photosynthesis up to a certain point where something else becomes the limiting factor so rate of photosynthesis remains constant even as the CO2 concentration/ light intensity keeps increasing

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16
Q

Describe how carbon dioxide (limiting factor) affects rate of photosynthesis

A

As carbon dioxide concentration increases so does rate of photosynthesis up to a certain point where something else becomes the limiting factor
After this point as CO2 concentration keeps increasing the rate of photosynthesis remains constant

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17
Q

Plateaued meaning

A

Where the rate of photosynthesis reaches a stage of no change after a period of progress (rate increasing)
This is where as the limiting factor increases, the rate of photosynthesis no longer does but remains the same (as it’s now another limiting factor that affects it)

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18
Q

What is Photosynthesis controlled by

A

Enzymes

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19
Q

Why at first does rate of photosynthesis increase as temperature increases

A

The enzymes involved can work more quickly and the molecules can move faster

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20
Q

What happens to rate of photosynthesis after enzymes have reach their optimum temperature

A

Enzymes start to denature
Active site can no longer bind to substrate
Rate of photosynthesis quickly decreases

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21
Q

Describe how temperature affects rate of photosynthesis

A

As temperature increases so does rate of photosynthesis as the enzymes can work quickly and the molecules can move faster as they have more kinetic energy
Up to the optimum temperature after which the enzymes denature and the active sites can no longer bind to the substrate so rate of photosynthesis quickly decreases

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22
Q

What can farmers to increase rate of photosynthesis

A

Grow plants in greenhouses (especially in colder climates) as it traps the sun’s heat to increase temperature
Use artificial light so photosynthesis can occur at night
Use a paraffin heater (releases heat and CO2 as it burns)
Fertilisers (ensure plants have enough essential minerals)
Use pesticides to kill unwanted pests

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23
Q

What is the equation linking light intensity and distance

A

Light intensity = 1/ distance squared

24
Q

Is respiration exothermic or endothermic and why

A

Exothermic
Releases energy

25
Q

3 ways organisms use energy from respiration

A

Build larger molecules from smaller ones (e.g proteins from amino acids)
Muscular contraction (for movement)
Maintaining body temperature

26
Q

Define metabolism

A

All the chemical processes that occur within a living organism in order to maintain life

27
Q

What is the most efficient way to transfer energy from glucose

A

Aerobic respiration

28
Q

Word equation for anaerobic respiration in muscles

A

Glucose-> lactic acid

29
Q

What does glucose produce if there isn’t enough oxygen

A

Lactic acid
(Anaerobic respiration in muscles)

30
Q

During anaerobic respiration why is there the incomplete breakdown of glucose molecules

A

There is no oxygen to oxidise it

(Makes it inefficient as not all energy from glucose molecule is unlocked)

31
Q

Word equation for anaerobic respiration in plants and yeast

A

Glucose-> ethanol + carbon dioxide

32
Q

What is produced from anaerobic respiration in plants and yeast

A

Ethanol and carbon dioxide

33
Q

When is lactic aid produced and when is ethanol and carbon dioxide produced in respiration

A

Ethanol and carbon dioxide- anaerobic respiration in plants and yeast
Lactic acid- anaerobic respiration in muscles

34
Q

What is fermentation

A

Anaerobic respiration in yeast
Lactic acid-> ethanol + carbon dioxide

35
Q

Two uses of fermentation in industry

A

Use yeast to make bread- produces carbon dioxide to help bread rise
Use yeast to make alcoholic drinks e.g beer and wine- produces ethanol

36
Q

When we exercise why do we need to carry out more respiration

A

Exercise requires us to move our muscles more than usual
Muscle contraction requires energy
Energy is released from respiration
More respiration means more energy released needed for this muscle contraction

37
Q

Why do our muscles need more oxygen during exercise

A

To carry out more respiration to release more energy for muscle contraction

38
Q

3 things that increase during exercise

A

Breathing rate
Heart rate
Breath volume

39
Q

Which type of respiration involves complete oxidation of glucose

A

Aerobic

40
Q

Which type of respiration involves incomplete oxidation of glucose

A

Anaerobic

41
Q

If glucose is fully oxidated does this mean more or less energy is released

A

More
(Aerobic respiration, whereas anaerobic is incomplete oxidation/ breakdown of glucose so not all energy from glucose is used and less energy is produced)

42
Q

Why does lactic acid build up during exercise

A

Anaerobic respiration occurs due to lack of oxygen for amount of energy needed

43
Q

Define oxygen debt

A

Amount of oxygen needed to react with lactic acid and remove it from the cells

44
Q

What happens once lactic acid has been oxidated by oxygen

A

It is converted back to glucose
(Oxidation takes place in liver as lactic acid is transported through blood from muscles)

45
Q

Once you’ve finished exercising how can your body get rid of the built up lactic acid

A

Reacting it with oxygen (converted to glucose)

46
Q

Where does oxidation of lactic acid take place and how does it get there

A

Liver
Moves from muscles through blood

47
Q

2 things that happen to muscles during long periods of activity

A

Become fatigued
Stop contracting efficiently

48
Q

Give 5 factors that affect metabolic rate

A

Age
Gender
BMI
Level of exercise
Genetics

49
Q

When there is a build up of lactic acid in the muscles after long periods of vigorous activity they become f…

A

Fatigued

50
Q

When you exercise does the amount of glycogen stored in the muscles increase or decrease

A

Decrease

51
Q

When you exercise why does the amount of glycogen stored in muscles decrease

A

It’s converted to glucose to be used in respiration to release energy for more muscle contraction

52
Q

Why do athletes ‘carb load’ before a big race

A

Maximises amount of glycogen stored which can then be converted to glucose for respiration to release more energy for more muscle contraction to help them run faster

53
Q

Why do birds and mammals have a higher rate of respiration than reptiles and fish

A

They need to regulate their body temperature and respiration releases the energy for this

54
Q

Equation of lactic acid reacting with oxygen

A

Lactic acid + oxygen -> carbon dioxide + water

55
Q

Chemical formula of lactic acid

A

C3H6O3

56
Q

Metabolic processes include the synthesis and breakdown of…

A

Carbohydrates, proteins and lipids

57
Q

Metabolic actions include the s… and b… of carbohydrates, lipids and proteins

A

Synthesis
Breakdown
E.g breakdown of glucose in respiration to release energy

GCSE Biology (15 decks)

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