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IGCSE Biology > Unit 3^Plant Physiology > Flashcards

Unit 3^Plant Physiology Flashcards

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1
Q

How is magnesium taken up by plants and what is it used for?

A

Magnesium is taken up by plants thru active transport

it is used to make CHLOROPHYLL 🍃

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2
Q

How are nitrates taken up by plants and what are they used for?

A

Nitrates are taken up by plants thru active transport

they’re used for making amino acids + growth

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3
Q

Where is adrenaline made in the body and what does it do?

A

Adrenaline is made in the adrenal glands [top of kidneys]
it triggers the ‘fight or flight’ which prepares body for action
It INCREASES HEART RATE (part of brain called medulla tells heart to beat faster)

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4
Q

What is meant by the term self-pollination

A

self-pollination=

Pollination which occurs in the same flower 🌷

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5
Q

What is meant by the term cross-pollination + what does this method rely on

A

Cross-pollination=
Pollination where pollen grains are transferred to a different flower 🌷 🌹

Relies on INSECTS 🦟 or WIND 💨to help them pollinate

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6
Q

Define the term ‘pollen grain’

A

A pollen grain is a structure in the plant that contains the male gamete

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7
Q

What is POLLINATION

A

Pollination is the transfer of pollen from anther to stigma

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8
Q

Suggest how the dry mass of 10kg of fresh potato tubers can be determined

A
  • weigh them on a weighing scale

* then heat them until all the water has evaporated + the mass stays the same

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9
Q

Why can’t you test a fresh leaf for starch? 🍃

A

If you put iodine solution on a fresh leaf nothing will happen cos the WAXY surface of the leaf will not absorb the solution (hence no colour change)

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10
Q

Design an experiment to test leaves for starch

A

1) remove a fresh leaf that’s been in sunlight
2) boil leaf in water for 30 seconds to kill it (stop chemical reactions in the leaf) 💦
3) boil it in ETHANOL to remove colour + waxy cuticle 🥂
4) now wash in cold water to soften it
5) spread the leaf on a tile + put 10 drops of iodine solution on leaf

** any parts of leaf that contain starch will go blue black !!!!

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11
Q

What is meant by the term ‘variegated leaf’

A

Variegated leaves are leaves with parts naturally without chlorophyll

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12
Q

Describe the process of photosynthesis

A

Plants use light energy from the sun 🌞(absorbed by chloroplasts 🍃) to convert CO2 + H2O 💦 into chemical energy (glucose) + oxygen

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13
Q

There are more stomata on the lower epidermis of a leaf, why is this?

A

There are more stomata on the lower epidermis,

Cos less EVAPORATION takes place on the cooler+ shady underside of the leaf

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14
Q

Design an experiment to measure the rate of photosynthesis

A

1) use an aquatic plant like algae or ELODEA
2) place it in a test tube of water and then into a water bath with a thermometer 🌡 (to keep temperature of beaker constant)
3) use a lamp + alter the distance away from pondweed using ruler
4) count the bubbles formed per minute
5) the more bubble per minute the faster the rate of photosynthesis

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15
Q

Name the 3 factors that affect the rate of concentration and explain how they do so

A

LIMITING FACTORS!

☀️ LIGHT INTENSITY
• if light increased so will rate of PS, but to a certain point — beyond CO2 or temperature will be limiting factor

🗯 CO2 Level/ concentration
• if co2 increases so will rate of PS, but to a certain point — beyond temperature of light will be limiting factor

🌡 TEMPERATURE
• as temperature increases so will rate of PS, but to a certain point — if temp TOO HIGH enzymes will denature hence rate of PS decreases
(Usually the temp is the limiting factor cos it’s too low)

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16
Q

What does the xylem do (it’s part of the vascular bundle)

A

Xylem carries water + mineral salts from roots up shoot

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17
Q

What does the phloem do (it’s part of the vascular bundle)

A

Phloem carries sucrose + amino acids to all parts of plant (translocation)

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18
Q

What do plants need nitrates for?

A

Needed for cell growth (makes amino acids)

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19
Q

What is a sign that a plant is deficient of nitrates

A

Yellow leaves + stunted growth

🌕🌕🌕🌕

20
Q

What do plants need phosphates for ?

A

To make DNA + cell membranes

21
Q

What is a sign that a plant is deficient of phosphates ?

A

Poor root growth + PURPLE older leaves 🔮🔮🔮🔮🔮

22
Q

What do plants need potassium for ?

A

To make enzymes

23
Q

What do plants need magnesium for?

A

🌱 need magnesium for making CHLOROPHYLL

24
Q

What is a sign that a plant is deficient of magnesium

A

Yellow leaves

🌕🌕🌕🌕

25
Q

State 4 things plants use glucose for

A
  • starch for storage
  • to make proteins + DNA
  • in cellulose for cell walls
  • respiration (duh!)
26
Q

What is diffusion

A

Diffusion is the net movement of particles from an area of high concentration to low

27
Q

What 3 factors affect diffusion

A

1) TEMPERATURE
gives particles more kinetic energy making them move faster/ collide more/ more successful collisions = diffuse faster

2)CONCENTRATION GRADIENT
the bigger the difference in concentration gradient — the faster the rate of diffusion (when conc high outside the cell, substances diffuse into it where it’s lower)

3) SA: volume ratio
as ratio increases so does the rate of diffusion

28
Q

Design a diffusion experiment in a NON LIVING system

A

1) cut agar jelly cubes of different SA:vol ration + put in dilute hydrochloric acid
2) time how long it takes for cubes to go colourless
3) the cube w the LARGEST SA:vol ration (smallest cube) will change colour fastest

4) Acid diffuses into the alkaline jelly cube + neutralises it
PINK💞 alkaline goes TRANSPARENT 🌫

29
Q

What is OSMOSIS

A

Osmosis is the net movement of water molecules across a partially permeable membrane from an area of high water potential to lower water potential

30
Q

What is meant by the term PLASMOLYSED CELL

A

PLASMOLYSED is when a plant cell loses water by osmosis, resulting in the cell membrane pulling away from the cell wall

31
Q

What happens to a plant cell when it is put in sucrose solution

A

The plant cells vacuole will shrivel up + pull away from cell wall— the plant cell becomes flaccid cos the water has moved out by osmosis

32
Q

What happens when an animal cell is placed in a pure water solution

A

It explodes as it has no cell wall to keep it

33
Q

What happens when an animal cell is placed in a sucrose solution

A

The animal cell shrinks — becomes CRENATED

34
Q

Why do plant cells need water

A

Because when a plant cell is well watered it becomes TURGID because of osmosis

These turgid cells make the contents of cell push up against the cell wall= TURGOR PRESSURE

35
Q

What happens if you don’t water a plant

A

The plant will wilt + lose turgor pressure

Cell becomes flaccid cos of no water

36
Q

Design an experiment to investigate the effects of osmosis in a living system

A

1) cut 3 potato tubers into identical cylinders
2) get beakers w 100cm^3 of pure water, v-concentrated sucrose solution and one with nothing (just potato)
3) leave cylinders in solution for 30 min

4) the ones in pure water = longer + fatter
The ones in sucrose solution = shorter + shrunk

37
Q

Define the term active transport

A

The movement of particles against a concentration gradient from an area of low concentration to high using energy released by respiration

38
Q

What makes the xylem vessels woody/strong

A

LIGNIN a woody material in the walls of the xylem vessels

39
Q

Describe fertilisation in a plant

A

Once a pollen grain lands on the stigma of a flower (cos of wind or insects)

A pollen tube grows out of the pollen grain, down thru the style to the ovary into the ovule

Fertilisation is when the two nuclei fuse together to make a zygote. This divides by mitosis to form an embryo

Each fertilised female gamete forms a seed. The ovary develops into a fruit around the seed

40
Q

Why do seeds need water

A

Water is needed to activate the enzymes that break down food reserves in the seed

41
Q

Why do seeds need oxygen

A

For respiration which transfers energy from food for growth

42
Q

Why do seeds need a suitable temperature for growth?

A

For enzymes inside seed to work

43
Q

Where does a seed get its glucose for respiration when it starts to germinate

A

Seed gets glucose from its food store for respiration

44
Q

What is germination

A

When seeds start to grow

45
Q

When does the seed stop using its food store

A

When the plant has grown enough to produce green leaves which means it can get its food (glucose) from photosynthesis for respiration

IGCSE Biology (6 decks)

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