Bioenergetics Flashcards

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1
Q

What do plants use as a source of energy?

A

Light from the sun

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2
Q

What is the name of the reaction that traps energy for plants

A

Photosynthesis

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3
Q

What type of reaction is photosynthesis?

A

Endothermic because it takes in energy

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4
Q

Where does photosynthesis take place in?

A

The leaf

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5
Q

How does photosynthesis occur?

A

Plant takes in carbon dioxide and water
The chlorophyll in chloroplasts absorb light energy
Light energy used in reaction to concert CO2 and H2O into glucose and oxygen

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6
Q

Photosynthesis word equation

A

Carbon dioxide + water ——> Glucose + Oxygen

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7
Q

Photosynthesis symbol equation (unbalanced)

A

CO₂ + H₂O ——> C₆H₁₂O₆ + O₂

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8
Q

Limiting factor in photosynthesis

A

When a factor lowers the rate of photosynthesis
So if you increase it the rate of photosynthesis will increase
But eventually rate stops increasing as something else becomes limiting factor

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9
Q

What could be a limiting factor?

A

Light intensity
Carbon dioxide level
Amount of chlorophyll
Temperature

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10
Q

Amount of chlorophyll as a limiting factor

A

The leaf will trap less light if there are low levels of chlorophyll in the leaf
Making it a limiting factor

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11
Q

How are limiting factors shown on a graph for photosynthesis
(CO2, chlorophyll, light intensity)?

A

The rate will increase as the factor increases showing it couldn’t have increased before as there wasn’t enough
It straightens off when it no longer is a limiting factor

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12
Q

Temperature as a limiting factor

A

Increasing it will increase rate of reaction
But if you increase it over the enzymes optimum it will denature and rate will fall

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13
Q

How is temperature limiting factor graph shown?

A

Rate increase as temperature increases
But falls to 0 as it reaches optimum temperature

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14
Q

What can plants use glucose from photosynthesis for?

A

For respiration to release energy
Starch
Fats and oils
Cellulose
Amino acids

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15
Q

Why do plants store glucose as starch?

A

It is insoluble
So can be stored and then converted back into glucose if they need it for respiration
Because at night time they cannot make more glucose with no photosynthesis so they can use the stored starch instead

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16
Q

Why do plants convert glucose to fats and oils?

A

As a storage form of energy

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17
Q

Why do plants make cellulose from glucose?

A

Because it strengthens the cell wall which keeps it from bursting

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18
Q

Why do plants make amino acids from glucose?

A

Amino acids are needed for protein synthesis

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19
Q

How do plants make amino acids from glucose?

A

From nitrate ions

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20
Q

How can we determine what the limiting factor is?

A

Increase the amount of another factor and record the rate of photosynthesis
If the rate increases then that was the limiting factor
If not repeat with another factor

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21
Q

Why do farmers want to increase the rate of photosynthesis

A

It increases yield of crops they want to produce

22
Q

How do farmers increase the rate of photosynthesis?

A

Oil burners = increase heat and carbon dioxide
Greenhouse = light heat and carbon dioxide increase

23
Q

Problem with increasing yield

A

Methods of increasing yield are expensive so the yield has to be justified

24
Q

What do humans need energy

A

Movement
Maintain body temperature
Chemical reactions to build larger molecules

25
Q

How do humans get energy

A

Respiration

26
Q

What type of reaction is respiration

A

Exothermic because it releases energy

27
Q

Aerobic respiration word equation

A

Glucose + oxygen ——> carbon dioxide + water + (energy)

28
Q

Why does aerobic respiration release a lot of energy?

A

Because the glucose molecule has been fully oxidised

29
Q

Aeróbic symbol equation

A

C₆H₁₂O₆ + O₂ ——> CO₂ + H₂O

30
Q

Anaerobic respiration

A

Happens when not enough oxygen is present

31
Q

Anaerobic respiration word equation in muscles

A

Glucose ——> Lactic acid+ (energy)

32
Q

Why does anaerobic respiration not release as much evidence?

A

Because the glucose molecule has not been fully oxidised

33
Q

Anaerobic respiration in plant/yeast cells

A

Glucose ——> ethanol + carbon dioxide

34
Q

Uses of yeast anaerobic respiration

A

Can make alcoholic drinks like beer
Can make bread as the carbon dioxide causes bubbles in the dough = rise

35
Q

Name for yeast anaerobic respiration

A

Fermentation

36
Q

Why do we need more energy during exercise?

A

For muscle contraction

37
Q

What changes with the body cells during exercise?

A

Increase in aerobic respiration
Therefore body cells demand more oxygen

38
Q

If the body cells demand more oxygen, what do we do?

A

Breathing rate and volume increases (more frequent deeper breaths)
To get more oxygen in blood stream
So heart rate increases to bump the oxygenated blood around

39
Q

What is the problem with exercising?

A

Not enough oxygen can be supplied to muscles especially if exercise is too vigorous
So we can’t aeróbically respire

40
Q

What do we do once we don’t have enough oxygen for aerobic respiration?

A

Respire anaerobically
But the oxidation of glucose incomplete = lactic acid builds up

41
Q

What happens when lactic acid builds up?

A

If we do a lot of vigorous activity = lactic acid makes muscles fatigued
So stop contracting efficiently

42
Q

What do we do when muscle fatigue happens?

A

We need to remove the lactic acid by oxidising it
Therefore enter a condition called oxygen debt

43
Q

How is lactic acid removed from muscles?

A

Transported out in the blood to the liver
Converted back to glucose in chemical reactions using oxygen

44
Q

Oxygen debt

A

The oxygen required to convert the lactic acid that has built up back to glucose

45
Q

Metabolism

A

The sun of all chemical reactions in a cell or the body

46
Q

How is metabolism and respiration linked?

A

Respiration releases energy
Which is used by enzymes to synthesise new molecules in a cell in chemical reactions
Metabolism = sum of these reactions

47
Q

Uses of glucose in plants

A

Cellulose = strengthens cell wall
Starch = storage form of glucose
Reacts with nitrate ions = amino acids = protein synthesis
Converted to fats and oils = storage form of energy

48
Q

Uses of glucose in humans

A

Glycogen = storage form released if blood sugar levels fall too low
Aerobic respiration

49
Q

Metabolism reaction for lipid

A

1 glycerol molecules
3 fatty acid molecules

50
Q

Where are lipids found?

A

In the cell membrane

51
Q

Metabolism reaction involving excess protein

A

Excess protein —> urea —> excreted