4.5 TRIPLE Plant hormones Flashcards Preview

SHHS - Science - AQA Biology Trilogy > 4.5 TRIPLE Plant hormones > Flashcards

Flashcards in 4.5 TRIPLE Plant hormones Deck (22)
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1
Q

What is positive phototropism?

A

When plant stems grow towards light

2
Q

What is positive gravitropism?

A

When plant roots grow downwards, with the force of gravity

3
Q

What type of plant hormone is responsible for cell elongation?

A

Auxin

4
Q

What do we call the lengthening of specific plant cells as a result of hormones?

A

Cell elongation

5
Q

What is Hydrotropism?

A

A plant’s ability to grow roots towards water

6
Q

What 3 things are Gibberellins responsible for?

A
  • Cell elongation
  • Seed dormancy
  • Germination
7
Q

Which plant hormone ripens fruit?

A

Ethene

8
Q

As well as ripening fruit, what other roles does ethene have?

A
  • Control of cell division

- Helps flowers open

9
Q

Auxins Experiments:

What happens when the tip is covered and light is shone to the side?

A

It grows upwards

10
Q

On which side does auxin accumulate when light is shone from the side on a stem

A

The shaded side

11
Q

Auxin Experiments:

What was used to create an impermeable barrier to stop hormone diffusion

A

Mica

12
Q

Where are auxins mainly produced (2 places)

A
  • Tips of shoots

- Roots

13
Q

How do auxins travel in plants?

A

By diffusion

14
Q

How does using auxins as selective weedkillers kill plants?

A
  • Causes some plants to grow uncontrollably

- Causes some plants to stop growing

15
Q

Gardeners can take cuttings to increase the number of plants they have.
Why do they need to use auxins in this process?

A

Rooting powders contain auxins, which helps the cuttings form roots.

16
Q

Why would fruits be sprayed with ethene during a long journey?

A

They can be picked before they are ripe then sprayed to begin the ripening process a short time before they arrive at supermarket

17
Q

Which hormone is used in horticulture to begin the germination process?

A

Gibberellins

18
Q

Which hormone is used in horticulture to increase the size of the fruit?

A

Gibberellins

19
Q

Describe an experiment that showed Auxin is produced in the shoot tip.

A
  • Cut shoot tip off or cover it

- It will not bend towards the light

20
Q

Auxin Experiments:

What is the difference between using a gelatine barrier and a mica barrier?

A

Gelatine - permeable to auxin

Mica - impermeable to auxin

21
Q

Auxin Experiments:

If you place a mica barrier on the shaded side, why does the plant not bend?

A
  • Mica stops Auxin diffusing down the shade side

- So, cells cannot elongate on shaded side (so cannot bend)

22
Q

Auxin experiments:

Why does a plant still bend towards the light if a mica barrier is placed on the light side?

A
  • Auxin diffuses down shaded side as normal

- Cells on shaded side can elongate as normal

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