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Biology > Topic 6 - Plant Structures And Their Functions > Flashcards

Topic 6 - Plant Structures And Their Functions Flashcards

1
Q

What do plants use to make their own food?

A

Photosynthesis

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2
Q

In what subcellular structure does photosynthesis happen inside of?

A

Photosynthesis happens inside of the chloroplasts, they contain chlorophyll which absorb the light.

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3
Q

Word equation for photosynthesis …
Symbol equation

A
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4
Q

Is photosynthesis an endothermic or extothermic reaction?

A

Photosynthesis is an endothermic reaction. Energy is taken in

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5
Q

What is the rate of photosynthesis affected by?

A

-light intensity

-the concentration of CO2

  • the temperature

-amount of chlorophyll

Any of these can become the limiting factor and stop photosynthesis from stopping any faster.

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6
Q

At what temperature do the enzymes needed for the photosynthesis reaction become denatured ?
What is the optimum temperature for a plant?

A

Around 45 degrees
Optimum - 21 degrees

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7
Q

What does not enough light do to the rate of photosynthesis?

A

It slows it down.

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8
Q

How’s energy transferred to the plant for photosynthesis ?

A

Light

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9
Q

What happens to the rate of photosynthesis as we increase light intensity?

A

As we increase light intensity , the rate of photosynthesis increases. They are directly proportional. However this is only up to a certain point.

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10
Q

How do we measure lights intensity?

A

Using a light meter

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11
Q

What happens to the light intensity as the distance of the lamp increases?

A

As the distance of the lamp increases, the light intensity decreases.

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12
Q

What is the inverse square law.
Light intensity ∝

A

Light intensity ∝ 1/ Distance (d)^2

∝means directly proportional to

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13
Q

What does the inverse square law mean?

A

If you halve the distance , the light intensity will be 4 times greater.

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14
Q

What happens to the rate of photosynthesis when we increase CO2 concentration?

A

The rate of photosynthesis is directly proportional to the CO2 concentration. It will increase up to a certain point until it’s no longer a limiting factor.

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15
Q

How do we test for starch in a leaf?
How do we know if there is starch present?

A

Do the iodine test
1) place leaf in boiling water for 30 seconds- This kills it and breaks down its cell wall.

2) place leaf in boiling ethanol- removes chlorophyll, making the leaf pale in colour. This is the control.

3)spread the leaf onto a white til and add iodine to test for the presence of starch.

We know there’s starch present if the iodine changes colour from yellow-brown to blue-black

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16
Q

How do root hairs take in minerals? Why?

A

They use active transport as the ground around them usually has a low concentration of nutrients than in the plant roots. Mineral ions are absorbed through microscopic hairs on the roots of a cell.

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17
Q

How do root hairs take in water?

A

Using osmosis. The millions of microscopic hairs on the roots absorb the water using osmosis

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18
Q

What process does the phloem do?

A

The phloem does translocation

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19
Q

What are assimilates?
Main assimilate in plants

A

Assimilates is the mixture inside the phloem. It’s very hard to separate. Sucrose

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20
Q

What is the main assimilate in plants?

A

Sucrose NOT Glucose

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21
Q

What is translocation?

A

Translocation is the movement of assimilates made by plant cells along the phloem.

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22
Q

What is the ‘source’ in the phloem?

A

The source is anywhere sucrose is released into the phloem. It produces the energy

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23
Q

What is the ‘sink’ in the phloem?

A

The sink is anywhere sucrose is removed from the phloem. It steals energy

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24
Q

Source, sink or neither? Why?
Leaf in summer-
Developing bud-
Xylem-
Actively growing root tips-

A

Leaf in summer - source as it’s doing photosynthesis and making sugars
Developing bud- sink as it needs energy to grow
Xylem- neither as it’s not involved with the transport of sucrose
Actively growing root tip- sink as it needs energy to grow

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25
How do we get sugars into the phloem and transported within it? (5 steps)
1) companion cells use ATP to actively transport hydrogen ions into the surrounding tissue. 2) this creates a diffusion gradient with a high concentration of hydrogen ions outside the companion cells. 3)hydrogen ions move back into the companion cells and bring sucrose with them. 4)this causes the concentration of sucrose in the companion cells to increase 5)sucrose moves from the companion cells to the sieve tube elements using plasmodesmata
26
What do xylem tubes do?
Carry water and minerals up the plant.
27
What do xylem tubes do?
Carry water and minerals up the plant.
28
What process takes water up the plant?
Transpiration
29
What are xylem tubes made up off? What material strengthens them?
Dead cells joined end to end with no end walls in between them and a hole in the middle. Strengthened with a material called lignin
30
What factors can affect transpiration rate ? And how?
-Temp , warm means the water particles have more energy to diffuse out the stomata -light intensity, stomata open up more in the light. -airflow(wind speed), if the airflow is poor water vapour surrounds the leaf, this means there’s a high concentration of water particles outside the leaf and diffusion happens slow -surface area of the leaf
31
What can measure the transpiration rate, light intensity , temp or air flow?
A potometer measures any of these independently
32
What’s the movement of water through the plant called?
The transpiration stream
33
How does the water leave the leaves of a plant ?
Water leaves the leafes of a plant through transpiration.
34
What takes ions and water up the plant?
The xylem
35
How does the water enter the roots?
Through osmosis
36
How do mineral ions enter the roots ?
Through active transport
37
What are the 4 essential mineral ions in a plant ?
Nitrogen Phosphate Potassium Magnesium
38
Why do plants need nitrogen ? Deficiency symptoms of plants without nitrogen? Explanation.
Use - growth, adaptations to environments Deficiency symptoms - short, spindly appearance that can lead to small leaf area Explanation- overwatering can cause this
39
Why do plants need phosphorus? Deficiency symptoms of phosphorus? Whay may cause a phosphorus deficiency?
1) phosphorus is essential for cell division and energy production. 2)short,spindly appearance 3)overwatering
40
Why do plants need pottasium? Pottasium deficiency symptoms? What may cause a pottasium deficiency?
1) plants need pottasium for optimal growth and protein synthesis 2)brown scorching of leaf tips 3) extreme moisture or compaction decreases oxygen levels in the soil.
41
What do plants need magnesium? Symptoms of a magnesium deficiency in plants ? Why may the deficiency happen?
1) enzyme activation and protein synthesis 2) yellowing , leaf veins 3) excess leeching of Mg nutrient
42
What plant can be used to measure the rate of photosynthesis ?
Canadian pondweed
43
What plant can be used to measure the rate of photosynthesis ?
Canadian pondweed
44
How do we measure the rate of photosynthesis ?
Use the gas syringe to measure the volume of oxygen produced
45
What does the loss of water in transpiration do?
Creates a shortage of water in the lead so more water is drawn up from the rest of the plant through xylem vessels to replace it.
46
What does the transpiration stream carry along with it?
Mineral ions.
47
What are stomata? What do they do?
-Stomata are tiny pores on the surface of a plant. -Stomata allow C02 and oxygen to diffuse directly in and out of a leaf. . -allow water vapour to escape during transpiration.
48
How does the water leave the stomata?
Through diffusion.
49
Why do leaves have a large surface area?
So they can capture more light which is needed for photosynthesis.
50
What does the palisade layer have lots of? And where is located and why?
The palisade layer has lots of chloroplasts. It is located at the top of the leaf so it can get the most light
51
Why is the upper epidermis transparent?
So light can pass through it and get to the palisade layer.
52
Why do epidermal tissues have a waxy coating?
To reduce water loss by evaporation.
53
Why do plants have small leaves or spines instead of leaves?
Because this reduces the surface area for water loss by evaporation. Spines help stop animals eating the plant to get water.
54
2 reasons Why some plants have thick waxy cuticles?
To reduce water loos by evaporation. Protect them from predators
55
Why do plants sometimes have fewer stomata or stomata that only open at night?
To reduce water loss by evaporation.
56
What is the meristem?
The point where growth occurs in plant.
57
What are auxins?
Auxins are plant hormones which control growth at the tips of roots and shoots.
58
Where are auxins produced
The meristem produced auxins
59
How do auxins move through the plant?
Auxins move through the plant in solution.
60
How do auxins stimulate the cell elongation process?
By diffusing backwards auxins stimulate the cell elongation process
61
What controls the plants growth response to light and gravity?
Auxins
62
What does sunlight do to auxins? What does this mean for the plant?
Sunlight destroys auxins. In tbe sun the plant will start using auxins but in tbe shade the auxins will still get used and the plant may then bend towards the sunlight
63
Definition of a hormone? Where do they travel and what are they secreted by?
A hormone is a chemical messenger that coordinated systems. Travel in tbe blood and are secreted by glands
64
What does it mean if a shoot is negatively gravitropic? How does this happen?
It grows away from gravity When it’s growing sideways, gravity produces an uneven distribution of auxin in the tip, with more on the lower side. This causes the lower side to grow faster and bend the plant upwards.
65
Why are shoots positively phototropic?
When it’s exposed to light it gets more auxins on the shaded side this makes the cells elongate faster on the shaded side. Causing the shoot to bend towards the light.
66
Why are roots positively gravitropic?
Because it will have more auxin in its lower side as it’s growing sideways. But in a root auxin stops growth, this means it will bend down
67
Why are roots negatively phototropic If exposed to light ?
In roots auxins inhibit cell elongation so the root bends downwards when auxins accumulate on the shaded side.
68
Common plant hormones and what do they do?
Prostaglandins - release stress signals in plants Ethane- emitted by bananas and ripens other fruit Gibberelins - create seedless fruits
69
What is tropism?
Tropism is a growth response to a stimulus
70
What are the 5 types of tropisms? (Growth response to a stimulus)
Phototropism Geotropsim( gravitropsm) Chemotropsim Thigmotropism Hydrotropsim
71
What is the stimulus for phototropism? Positive or negative in the roots and shoots? Explanation?
Light Roots: negative tropism Shoots:positive tropism Roots grow away from light Shoots grow towards light
72
What is the stimulus for geotropism (gravitropism)? Positive or negative in the roots and shoots? Explanation?
Gravity Roots: positive geotropism Shoots: negative gravitropism Roots grow towards gravity Shoots grow away from gravity
73
What’s the stimulus for chemotropism? Positive or negative in the roots and shoots? Explanation?
Chemicals Roots- positive chemotropism because they’re trying to reach the chemicals in the soil Shoots- negative chemotropism because they go up
74
What’s the stimulus for thigmotropism? Positive or negative in the roots and shoots? Explanation?
Movement/touch Shoots- positive thigmotropism as it helps plants direct their direction of growth Roots- negative thigmotropism as the roots need to avoid rocks etc.
75
What’s the stimulus for hydrotropism? Positive or negative in the roots? Explanation?
Water Roots- positive hydrotropism because the roots get water for the plant
76
where does transpiration happen? Translocation?
Transpiration in the xylem Translocation in the phloem

Biology (10 decks)

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