year 9 term 2

Question 1

When does diffusion happen?

Answer 1

WHen there is a difference in concentration between 2 places

Question 2

Factors affecting diffusion?

Answer 2

• Concentration gradient; steeper the better.
• Distance-smaller distance more diffusion
• SA:V ratio, larger ratio, more diffusion
• Temperature; higher temp. more KE in particles.

Question 3

defien water potential

Answer 3

how “free” the water if to move, more water potential gradient, more osmosis.

Question 4

Term for when a plant cell has lots of water?(or is packed with water)

Answer 4

Turgid; is important for plants.

Question 5

Why is being turgid important for a plant cell?

(or being turgor)

Answer 5

To maintain a steep water potential gradient for osmosis.

Question 6

What happens a plant cell starts to loose water?

Answer 6

It becomes flaccid.

Question 7

What happenns when a plant cell has lost too much water?

Answer 7

it becomes plasmolysed-the cytoplam starts leaving the cell wall.

Question 8

Why may active transport be important to a cell?

Answer 8

To control it’s intake of a substance.

Question 9

root hair cells are the — —— —— —- of a plant

Answer 9

Main water uptake site

Question 10

What happens to an animal cell if it gains too much water?

Answer 10

It swells and bursts

Question 11

What happens to an animal cell once it looses too much water?

Answer 11

It shrivels and forms edges.

Question 12

State the path taken by the water to the xylem?

Answer 12

Root hair cell—->cortex—->xylem

Question 13

How does osmosis gaina steep gradient in plants?

Answer 13

By transpiration-loss of water through the leaves.

Question 14

Define a transpiration stream

Answer 14

Continuos flow of water through stem to xylem and into the leaves to replace water lost in transpiration continuosly.

Question 15

Functions of transpiration stream

Answer 15

• Cool leaf
• Keep cells turgid
• Supply water to cells
• carry mineral ions

Question 16

Features of the xylem

Answer 16

• Dead cells
• No cytoplasm
• Hollow lumen
• Ligning cell walls
• impremeable to water

Question 17

Define lignification

Answer 17

Cytoplasm of cells—>lignin—->cell walls.

Makes the xylem stronger so it can take water up to large plants.

Question 18

Features of phloem

Answer 18

• lining of cells have sieves/sieve plates
• cytoplasm extended
• Brings products to plants; starch/sucrose(around plant), amino acids to new leafs.
• controlled by nuclei of companion cells.

Question 19

Define the sieve plate

Answer 19

holes in the membranes of phloem cells, so they all share cytoplasm.

Question 20

Describe the vascular bundle in new stems

Answer 20

Little vascular bundles around the circle

Question 21

Features of stomata

Answer 21

• have chloroplasts
• Adapted to be present more on the bottom than the top
• Open and close based on needs
• allow for transpiration
• Able to become Flaccid or turgid
• Banana shaped
• thicker cellulose near pore

Question 22

Why are there more stomata on the bottom of a leaf than the top

Answer 22

The leaf has adapted this so transpiration doesn’t occur as often, to stop water losss essentially.

Question 23

How do stomata open and close

Answer 23

They are turgid to begin with as they get water from surrounding epidermis cells, so they swell up and curve. However during the night there is more water loss, due to this they loose water, become flaccid and close.

Question 24

Why is it helpful that stomata close at night?

Answer 24

Stops transpiration, is helpful as there’s no need to cool down the leaf or perform photosynthesis

Question 25

Uses of glucose ina plant

Answer 25

- An energy store(starch) - To form lipids(energy in seeds, present in seeds) - To form proteins - Make DNA - Respiration - Sucrose (for the phloem to transport) - chlorophyll

Question 26

Use of Mg in plants

Answer 26

Chlorophyll

Question 27

Use of nitrates in plants

Answer 27

to make proteins(**for growth**) as well as DNA

Question 28

Colour of Hydrogen carbonate indicator when concentration of CO2 is >0.04%

Answer 28

yellow

Question 29

Colour of Hydrogen carbonate indicator when concentration of CO2 is =0.04% ## Footnote (0.04% is the normal concentration of CO2 in our air.)

Answer 29

orange

Question 30

Colour of Hydrogen carbonate indicator when concentration of CO2 is <0.04%

Answer 30

purple

Question 31

3 factors that affect photosynthesis

Answer 31

- Light - CO2 - Temperature

Question 32

When do the factors affecting photosynthesis stop become limiting factors?

Answer 32

When the volume required is met.

Question 33

Purpose of the spongy mesophyll layer

Answer 33

Main respiration/gas exchange site

Question 34

Purpose of palaside layer and it's adaptation for it

Answer 34

Photosynthesi; close to the light

Question 35

Lower epidermis purpose/adaptation

Answer 35

full of stomata

Question 36

Upper epidermis purpose

Answer 36

Prevent water loss and micro-organisms entering

Question 37

Upper epidermis adaptation

Answer 37

Transparent so light can enter- waxy layer on top of it.

Question 38

How do you de-starch a leaf?

Answer 38

Place it in the dark for 2-3 days

Question 39

How to remove CO2 around a leaf?

Answer 39

Seal it in a glasss jar with soda lime(which absorbs the CO2)

Question 40

How do I test a leaf for starch?

Answer 40

1. Get a leaf 2. Heat in water bath for 30s 3. Turn off heat, Place leaf in a tube of ethanol, then place tube in the water bath, let it heat for 30 s 4. Wash the leaf with cold water 5. Test with iodine

Question 41

Why can't you immediately test a leaf for starch?

Answer 41

Waxy cuticle doesnt allow sollution to enter palaside layer- Hence we boil it in water for 30s

Question 42

Why is turning of the heat below the water bath in an experiment to test a leaf for starch important before placing the test tube of ethanol in it?

Answer 42

Ethanol is flammable.

Question 43

Factors affecting transpiration

Answer 43

- Light - Temperature - Humidity; less transpiration in humid as less diffusion between inside and outside of leaf - Wind; the more windy it is the more moisture(i.e water) leaves stomata, hence more transpiration in windy conditions than normal.

Question 44

Describe the "weight potometer method"to measure transpiration

Answer 44

By covering the soil and plant with a polytheine bag and placing it on a scale; in a certain amount of time you will be able to measure the difference in mass as water has been lost in transpiration ## Footnote * While some weight may be lost due to photosynethesis and respiration-water is the main loss here, hence most of the weight lost is water weight.

Question 45

Describe the "volume potometer"method to measure transpiration.

Answer 45

Once you cut off a stem/stock of a plant, place it in the apparatus, after a certain period of time you shall see the bubble in the water has moved(as water was taken up by the xylem in the stem), measure the distance it moved.

Question 46

what is similar in osmosis and diffusion?

Answer 46

- both are passive - both require a steep concentration gradient

Question 47

Adaptations of a leaf

Answer 47

- Waxy cuticle - Large SA - Air space - Thin - Stomata in lower epidermis - Stoamta are turgid - Flat - Small pores

Question 48

Intercellular adaptations of a leaf

Answer 48

- Stomata surrounded by guard cell - Spongy mesophyll have a little film of water - Stomata protected by waxy cuticle ont op of leaf - stomata are away from the sun(protected from sun)

Question 49

chemical formula of photosynthesis

Answer 49

6CO2+6H2O----->C6H12O6+60

Question 50

Word equation of photosynthesis

Answer 50

Water+carbon dioxide--->glucose+oxygen