plant nutrition and transport

Question 1

what is photosynthesis

Answer 1

it is the process that produces food in plants, the food it produces is glucose

Question 2

where does photosynthesis happen

Answer 2

in the leaves of all green plants, this is largely what the leaves are for

Question 2

photosynthesis happens in…

Answer 2

chloroplast which are found in leaf cells and other green parts of the plant
chloroplast contain a pigment called chlorophyll which absorb sunlight and uses its energy to convert carbon dioxide and water into glucose, oxygen is also produced

Question 2

why is photosynthesis an important process

Answer 2

because it converts light energy to chemical energy, which is stored in the glucose
this chemical energy is released when glucose is broken down during respiration

Question 3

a simple explanation of photosynthesis

Answer 3

-Photosynthesis is the process that plants use to make their own food. They take in carbon dioxide (CO₂) from the air and water (H₂O) from the soil, and with the help of sunlight and a green pigment called chlorophyll, they produce glucose (a type of sugar) and oxygen (O₂).

• Provides Food:
  Plants make glucose to grow and store energy. This energy is passed on to animals and humans when they eat plants.

Releases Oxygen:
Photosynthesis produces oxygen, which humans and animals need to breathe.

Maintains Balance:
It helps remove carbon dioxide from the air, keeping the atmosphere stable.

Question 4

word and symbol equations for photosynthesis

Answer 4

carbon dioxide + water => glucose + oxygen

Question 4

what is a limiting factor

Answer 4

something that stops photosynthesis from happening any faster
light intesity , CO2 concentration and temperature can all be the limiting factor

Question 5

3 limiting factors

Answer 5

• light intensity (wave length + color)
• CO2 concentration
• temp (enzymes)

Question 6

what do limiting factors depend on

Answer 6

the limiting factor depends on the environmental conditions. eg. in winter low temps might be the limiting factor. at night, light is likely to be the limiting factor

Question 7

state –> not enough light slows down the rate of photosynthesis

Question 7

light intesity and the effect of photosynthesis

Answer 7

• chlorophyll uses light energy to preform photosynthesis
• it can only do it as quickly as the light is arriving
• if the light intestity is increased, the rate of photosynthesis will increase steadily, but only up to a certain point
  beyond that it wont make any difference because then it will be either the temp or CO2 level which is now the limiting factor

Question 7

state -> too little CO2 slows down the rate of photosynthesis.

Question 8

effect of CO2 on photosynthesis

Answer 8

as with the light intesity , increasing the concentration of CO2 will only increase the rate of photosynthesis up to a certain point. After this the graph flattens out, showing that CO2 is no longer the limiting factor.
as long as light and CO2 are in plentiful supply then the factor limiting photosynthesis must be temperature

Question 8

effect of temp of photosynthesis

Answer 8

as the temp increases so does the rate of photosynthesis to a certain point
if the temp is too high (over about 45 degrees) the plants enzymes will denature so the rate of photosynthesis rapidly decreases.
usually if the temp is the limiting factor its because its too low, and things need warming up a bit

Question 8

what are leaves designed for

Answer 8

making food by photosynthesis

Question 9

MEMORISE THE DESIGN FOR LEAVES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Question 10

what are all the parts for leaves

Answer 10

• palisade mesophyll layer
• spongy mesophyll layer
• air space
• stoma
• guard cell
• waxy cuticle
• lower epidermis
• vascular bundle
• chloroplasts
• upper epidermis

Peter Saw A Small Green Worm Lying Very Calm Underwater

Question 11

state –> leaves are broad so there is a large surface area exposed to light

Question 11

where are most of the chloroplasts found

Answer 11

in the palisade layer since they can get the most light

Question 11

why is the upper epidermis transparent

Answer 11

the upper epidermis transparent so that light can pass through it to the palisade layer

Question 12

what are vascular bundles

Answer 12

they are transport vessels xylem and phloem. they deliver water and other nutrients to every part of the leaf and take away the glucose produced by photosynthesis. they also help to support the leaf stucture

Question 13

what does the waxy cuticle do

Answer 13

helps to reduce water loss by evaporation

Question 14

what do the adaptions of leaves for efficient gas exchange do

Answer 14

make photosynthesis more efficient. eg. the lower surface is full of little holes called stomata. which let CO2 diffuse directly into the leaf

Question 15

why do plants need three main mineral ions for growth

Answer 15

• so they can produce important compounds
• they get these elements from mineral ions in the soil
  if there are not enough of these mineral ions in the soil, plants suffer from deficiency symptoms

Question 15

what 4 main minerals ions are needed for growth

Answer 15

- nitrates - phosphates - potassium - magnesium

Question 16

phosphates

Answer 16

contain phosphorus for making DNA and cell membranes and they are needed for respiration and growth. plants without enough phosphate have poor root growth and their older leaves are purple

Question 16

nitrates

Answer 16

contain nitrogen for making amino acids and proteins. these are needed for cell growth. if a plant cant get enough nitrates it will be stunted and older leaves will turn yellow

Question 16

potassium

Answer 16

to help the enzymes needed for photosynthesis and respiration. if there is not enough potassium in the soil, plants have poor flower and fruit growth and discoloured leaves.

Question 16

why is magnesium needed in small amounts

Answer 16

- magnesium is required for making chlorophyll which is needed for photosynthesis - plants without enough magnesium have yellow leaves

Question 17

test leaf for starch

Answer 17

- dunk leaf in boiling water - put leaf in boiling tube with some ethanol and heat in an electric water bath until it boils - this gets rid of any chlorophyll and makes leaf white colour - rinse leaf in cold water and add few drops of iodine solution, if starch is present the leaf will turn blue-black.

Question 18

what does the starch test show

Answer 18

whether photosynthesis is taking place

Question 19

if a plant cant photosynthesise...

Answer 19

it cannot make starch

Question 20

how do you show that chlorophyll is needed for photosynthesis

Answer 20

using variegated (green and white) leaves. Only the green part contains chlorophyll. - take a variegated leaf from a plant that has been exposed to light for a bit. Record which bits are green and which are not. - test the leaf for starch. Only the bits that are green will turn blue-black. - this suggests that only the parts of the leaf that contain chlorophyll are able to photosynthesise and produce starch.

Question 20

how to show that CO2 is needed for photosynthesis.

Answer 20

You need a sealed bell jar, soda lime, a plant, and a light source (lamp) - the soda lime will absorb CO2 out of the air into the jar - if you leave the plant in the jar for a while and test a leaf for starch, it wont turn blue-black - this shows that no starch has been made in the leaf, which means that CO2 is needed for photosynthesis

Question 21

how do you show that light is needed for photosynthesis

Answer 21

- you need a plant that has been grown without ant light. eg in a cupboard for 48 hours. this will mean that it has used up its starch stores. - cut a leaf from the plant and test it for starch using iodine solution. the leaf will not turn blue-black - this shows that light is needed for photosynthesis, as no starch has been made.

Question 21

how do you make the no light in plant experiment a fair test

Answer 21

you need to make sure that it is warm enough to photosynthesise and that there is plenty of CO2 or it will not be a fair test.

Question 22

what does oxygen production show

Answer 22

it shows the rate of photosynthesis

Question 23

what can be used to measure the effect of light intensity on the rate of photosynthesis

Answer 23

- canadian pondweed. - the rate at which the pondweed produces oxygen corresponds to the rate at which it is photosynthesising. - the faster the rate of oxygen production, the faster the rate of photosynthesis

Question 24

how do you do the oxygen production showing the rate of photosynthesis test

Answer 24

- you need a ruler to vary the distance from plant, a light source, a clamp, syringe, canadian pondweed, water, sodium hydrogencarbonate, capillary tube - the gas syringe should be empty to start with. sodium hydrogencarbonate may be added to the water to make sure the plant has enough carbon dioxide. ( it released the CO2 into the solution) - a source of white light is placed at a specific distance from the pondweed. - the pondweed is left to photosynthesise for a set amount of time. as it photosynthesises, the oxygen released will be collected in the capillary tube. - at the end of the experiment, the syringe is used to draw out the gas bubble in the tube up alongside a ruler and the length of the gas bubble is measured. this is proportional to the volume of oxygen produced. - for this experiment any variables such as the temp or the time the pondweed is left to photosynthesise is controlled. - the experiment is repeated with the light source placed at different . distances from the pondweed.

Question 25

what is transpiration

Answer 25

the loss of water from the plant

Question 26

what is transpiration caused by

Answer 26

the evaporation and diffusion of water from a plant's surface

Question 27

where does most transpiration happen

Answer 27

at the leaves

Question 28

what does the evaporation create

Answer 28

a slight shortage of water in the leaf and so more water is drawn up from the rest of the plant through the xylem vessels to replace it this intern means more water is being drawn from the root and so there is a constant transpiration stream of water through the plant

Question 29

state --> transpiration is the side effect of the way leaves are adapted for photosynthesis. they have to have stomata in them so that gases can be exchanged easily. bcs theres more water inside the plant than in the air outside, the water escapes from the leaves through the stomata by diffusion.

Question 30

what are the 4 main factors that transpiration is affected by

Answer 30

light intesity, temp, wind speed, humidity

Question 31

light intensity

Answer 31

the brighter the light, the greater the transpiration rate stomata begin to close as it gets darker. photosynthesis cannot happen in the dark, so they do not need to be open to let CO2 in. when the stomata is closed , very little water can escape

Question 32

temp

Answer 32

the warmer it is, the faster transpiration happens. when it is warm, the water particles have more energy to evaporate and diffuse out of the stomata

Question 32

wind speed

Answer 32

the higher the wind speed around a leaf, the greater the transpiration rate. if wind speed around a leaf is low, the water vapour just surrounds the leaf and does not move away. this means there is a high concentration of water particles outside the leaf as well as inside it, so diffusion doesnt happen quickly if it is windy, the water vapour is swept away, maintaining a low concentration of water in the air outside the leaf. diffusion then happens quickly, from an area of high concentration to an area of low concentration

Question 33

humidity

Answer 33

the drier the air around a leaf, the faster transpiration happens. this is like what happens with air movement. if the air is humid there is a lot of water in it already, so there is not much of a difference between the inside and outside of the leaf. diffusion happens fastest if there is a really high concentration in one place, and a really low concentration in the other.

Question 34

what is a potmeter

Answer 34

a special piece of apparatus used to estimate transpiration rates

Question 34

measuring transpiration

Answer 34

- cut a shoot underwater to prevent air from entering the xylem. cut it at a slant to increase the surface area available for water uptake - assemble the potometer in water and insert the shoot under water , so no air can enter - remove the apparatus from the water but keep the end of the capillary tube submerged in a beaker of water. - check the apparatus is watertight and airtight - dry the leaves and allow time for the shoot to acclimatise and then shut the tap - remove the end of the capillary tube from the beaker of water until one air bubble has formed, then put the end of the tube back into the water. - record the starting position of the air bubble. - start the stopwatch and record the distance moved by the bubble per unit time, eg per hour - keep the conditions constant throughout the experiment, eg temp and air humidity

Question 34

what do all cell organisms need to get rid of

Answer 34

waste substances

Question 35

unicellular organisms - waste substances

Answer 35

these substances can diffuse directly in and out of the cell across the cell membrane. the diffusion is quick because of the short distances substances have to travel

Question 35

what are the two main transport systems

Answer 35

- xylem tubes that transport water and minerals - phloem tubes that transport food

Question 35

multicellular organisms - waste substances

Answer 35

multicellular organisms ( animals and plants ) direct diffusion from the outer surface would be too slow - that is because substances would have to travel large distances to reach every cell. so multicellular organisms need transport systems to move substances to and from individual cells quickly

Question 36

xylem

Answer 36

the xylem carry water and mineral salts from the roots up the shoot to the leaves in the transpiratiion stream

Question 37

phloem

Answer 37

- the phloem transport sugars, like sucrose and amino acids from where they are made in the leaves to other parts of the plant - this movement of food substances around the plant is known as translocation

Question 37

what do root hairs do

Answer 37

take in water

Question 38

root hairs take in water...

Answer 38

- the cells on plant roots grow into long hairs which stick out into the soil - each branch of a root will be covered in millions of these microscopic hairs - this gives the plant a big surface area for absorbing water from the soil

Question 39

what is water taken in by

Answer 39

osmosis - there is usually a higher concentration of water in the soil than there is inside the plant, so the water is drawn into the root hair cell by osmosis

Question 40

what do root hair cells also take in

Answer 40

minerals, this is done by active transport