4.4 Photosynthesis Flashcards

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1
Q

Explain the shape of the graph at point A.

A

The rate of photosynthesis is increasing as temperature increases.

Becauses enzymes and substrates have more kinetic energy.

So there are more successful collisions.

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2
Q

What is the main limiting factor of photosnthesis during winter.

A

Temperature

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3
Q

What is the equation for photosynthesis?

A
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4
Q

Explain the shape of the line at point B on the graph:

A

Photosynthesis is happening at its optimum rate.

Becauses enzymes and substrates have maximum kinetic energy.

So there are maximum possible successful collisions.

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5
Q

DESCRIBE the graph below:

A

As temperature increases, rate of photosynthesis increases.

A maximum rate is reached.

Then the rate ogf photosynthesis decreases rapidly past the optimum temperature and stops at 45°C

Remember: you must include numbers from axis if they are given!!

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6
Q

How do plants make Amino acids?

A

They combine glucose with nitrates.

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7
Q

When using a lamp to look at how light intensity affects rate of photosynthesis, how can we increase the light intensity?

A

Move the lamp closer.

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8
Q

What is the symbol for magnesium ions?

A

Mg2+

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9
Q

Identify the limiting factor/s at point B

Explain how you know.

A

CO2 conc/Temperature/Chlorophyll/Water

Because when light intensity increases past this point rate of photosynthesis does not - so must be one of the other factors.

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10
Q

Identify the limiting factor at point A.

Explain how you know.

A

CO2 concentration.

because as CO2 concentration increases so does the rate of photosynthesis

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11
Q

What is the symbol for nitrates?

A

NO3-

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12
Q

What is meant by a limiting factor of photosynthesis?

A

Something that slows down the amount of photosynthesis that a plant can do.

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13
Q

Which type of energy allows carbon dioxide and water to be converted into glucose and oxygen?

A

Light energy

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14
Q

DESCRIBE the graph below…

A

As light intensity is increases rate of photosynthesis increases.

Eventually, the rate of photosynthesis remains constant.

Remember: if numbers are on the axis’ you mst include them in your description!!

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15
Q

Where do plants get nitrates?

A

From the soil

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16
Q

Why do plants need magnesium ions from soil?

A

to make chlorophyll

17
Q

What is the symbol equation for photosynthesis?

A
18
Q

Identify the limiting factor at point A.

Explain how you know.

A

Amount of light

because as light intensity increases so does the rate of photosynthesis

19
Q

Identify the limiting factor/s at point B.

Explain how you know.

A

Light Intensity/Temperature/Chlorophyll/Water

Because when CO2 concentration increases past this point rate of photosynthesis does not - so must be one of the other factors.

20
Q

What is the main limiting factor of photosynthesis on a Summer day? Explain your answer.

A

CO2 concentration.

Because it is generally warmer in Summer.

Because there is a higher light intensity in Summer.

Atmospheric CO2 is low (0.03%).

21
Q

Explain the shape of the graph at point C.

A

The rate of photosnthesis is decreasing rapidy past the optimum temperature.

Because enzymes are denaturing.

Change to shape of active site.

Fewer successful collisions.

22
Q

What 5 things do plants use glucose for?

A
  1. Oils - energy store
  2. Starch - energy store
  3. Cellulose - for cell walls
  4. Amino acids - for growth and repair
  5. Respiration - for energy

OSCAR (wil help you remember!)

23
Q

DESCRIBE the graph below:

A

As CO2 concentration is increases rate of photosynthesis increases.

Eventually, the rate of photosynthesis remains constant.

Remember: if numbers are on the axis’ you mst include them in your description!!

24
Q

A plant tha is lacking magnesium will show what symptoms?

A

Yellow leaves as less chlorophyll.

Poor growth as less photosynthesis happening.

25
Q

What is the main limiting factor of photosynthesis at night time?

A

The amount of light

26
Q

Starch is insoluble in the cytoplasm of plant cells. Why is this a useful property?

A

It does not increase the concentration of cytoplasm.

So water does not move into the cell via osmosis which would cause the cell to swell up.

27
Q

What are the limiting factors of photosynthesis?

A
  1. Light
  2. CO2 concentration.
  3. Temperature
  4. Amount of chlorophyll
  5. Water availability
28
Q

As you move a plant away from a lamp, the light intensity reaching the plant decreases. We say that distance and light intensity are i__________ p_____________.

A

inversely proportional

29
Q

How can we calculate the light intensity coming from a lamp that is reaching a plant?

A

The Inverse Square Law

Light intensity = 1 ÷ Distance of plant from lamp²

30
Q

How do farmers optimise conditions for photosynthesis?

A

The grow crops in a greenhouse.

31
Q

How do greenhouses optimise photosynthesis?

A
  1. Artificial lighting allows photosynthesis to occur at night.
  2. Shades - can be shut if it gets too warm.
  3. Propane burner - releases CO2
  4. Maintain optimum temp for photosnyhtesis.
  5. Glass allows light to reach crops.
  6. Fertilisers can be used to supply minerals e.g. magnesium
32
Q

A lamp is 30cm from some pond weed. What is the light intensity?

A

Light intensity = 1 ÷ Distance of plant from lamp²

1/30² = 0.001

33
Q

A lamp is 10cm away from some pond weed. What is the light intensity?

A

Light intensity = 1 ÷ Distance of plant from lamp²

1/10² = 0.01

34
Q

A lamp is 20cm away from some pond weed. What is the light intensity?

A

Light intensity = 1 ÷ Distance of plant from lamp²

1/20² = 0.0025

35
Q

The light intensity of a lamp is 0.0001. How far from the pond weed is the lamp?

A

Light intensity = 1 ÷ Distance of plant from lamp² is rearranged to:

Distance of plant from lamp = √(1/light intensity)

Therefore:

√(1/0.0001) = 100 cm away