Plant Nutrition and Transport Flashcards
what is photosynthesis?
the process that produce ‘food’ in plants
what is the ‘food’ produced in photosynthesis?
glucose
where does photosynthesis happen?
in the leaves of all green plants
where does photosynthesis happen inside of? (not where it happens)
inside the chloroplast which are found in leaf cells and in other green parts of a plant
what does the pigment chloroplast contain?
chlorophyll
what does chlorophyll do?
it absorbs sunlight and uses its energy to convert carbon dioxide and water into glucose. Oxygen is also produced
why is photosynthesis an important process?
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
what is the word equation for photosynthesis?
carbon dioxide + water -> glucose + oxygen
what is the symbol equation for photosynthesis?
6CO2 + 6H2O -> C2H12O6 + 6O2
what does the rate of photosynthesis depend on?
on the limiting factors it is at the moment
what is a limiting factor?
something that stops photosynthesis from happening any faster
what are 3 limiting factors?
- light intensity
- CO2 concentration
- temperature
what do limiting factors depend on?
on environmental conditions (e.g in winter low temperatures might be the limiting factor)
what does chlorophyll use to perform photosynthesis?
light energy
what is the effect on photosynthesis if light intensity increases?
the rate of photosynthesis will increase, but only to a certain point
why does photosynthesis increase only until a certain point?
because either CO2 or the temperature will be a limiting factor
what is the effect of increasing CO2 in photosynthesis?
it will increase the rate of photosynthesis up to a point
why does temperature affects the rate of photosynthesis?
because it affects the enzymes involved
what is the effect of increasing temperature on photosynthesis?
the rate of photosynthesis increases as well until a certain point
what will happen to plants if the temperature is too high (45 degrees)?
the plant’s enzymes will be denatured (destroyed), causing the rate of photosynthesis to rapidly decrease
usually why is temperature a limiting factor?
because it is too low, the plants needs a little bit of warming up
most photosynthesis takes place where?
in the leaves
leaves are designed for what?
for making food by photosynthesis
describe the diagram of a typical leaf find the: - stomata - waxy cuticle - chloroplast - vascular bundle - palisade layer - spongy layer
handmade flashcard 22
what are leaves adapted for?
for efficient photosynthesis
why are leafs broad?
so that there is a large surface area exposed to light
where is most chloroplast found in leafs?
in the palisade layer
why is most chloroplast found in the palisade layer?
so that they are near the top of the leaf where they can get the most light
leaves have a network of what?
of vascular bundles
what are vascular bundles?
they are transport vessels: xylem and phloem
what does the vascular bundles do?
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 structure
what does the waxy cuticle in the leaf help with?
it reduces water loss by evaporation
how does the adaptations of leaves for efficient gas exchange help photosynthesis?
it makes photosynthesis more efficient
how is glucose stored by plants?
it is stored by starch
what are two products from photosynthesis
glucose and starch
how do you test a leaf for starch?
Practical
1) first dunk the leaf in boiling water (hold it with tweezers). This stops any chemical reactions happening inside the leaf
2) now put the leaf in a boiling tube with some ethanol and heat it in an electric water bath until it boils (this gets rid of any chlorophyll and makes the leaf a white-ish colour)
3) rinse the leaf in cold water and add a few drops of iodine solution, if starch is present the leaf will turn blue-black
what can’t a plant make if it doesn’t photosynthesise?
starch
what is starch?
a chain of glucose molecules which are bound together. Also, it can be seen as the colour of a leaf
experiment to show that chlorophyll is needed for photosynthesis
(3 steps)
1) take a variegated (green and white) leaf from a plant that’s been exposed to light for a bit. Make sure you record which bits are green and which bits aren’t
2) test the leaf for starch. Only the bits that were green turn blue
3) only the parts of the leaf that contained chlorophyll are able to photosynthesise and produce starch
experiment to show that CO2 is needed for photosynthesis
4 steps
1) find a place with light and place a plant and a soda lime close to each other. Then put a sealed bell jar on top of them.
2) the soda lime will absorb CO2 out of the air in the jar
3) leave the plant in the jar for a while and then test the leaf for starch, and it won’t turn blue-black
4) no starch in leaf -> CO2 is needed for photosynthesise
what does the starch test show?
where photosynthesis is taking place
experiment to show that light is needed in photosynthesis
1) you’ll need a plant that’s been grown without any light (e.g a plant that has been inside a cupboard for 48 hours. It will have used its starch stores)
2) cut a leaf from the plant and test it for starch using iodine solution. The leaf won’t turn blue-black
3) this shows light is needed for photosynthesis, since no starch was made
what plant can be used to measure the effect of light intensity?
Canadian pondweed
why is Canadian pondweed used to measure the effect of light intensity
because the rate at which the pondweed produces oxygen corresponds to the rate at which it’s photosynthesising
practical for showing that oxygen productions shows the rate of photosynthesis
(6 steps)
1) the apparatus is set up according to diagram (handmade flashcard 23). The gas syringe should be empty. Sodium hydrogencarbonate may be added to water to make sure the plant has enough carbon dioxide (it releases CO2 in solution)
2) a source of white light is placed at a specific distance from the pondweed
3) the pondweed is left to photosynthesise for a set amount of time. As it photosynthesises, the oxygen released will collect in the capillary tube.
4) at the end of the experiment, the syringe is used to draw 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 O2 produced
5) any variables that could affect the results should be controlled (e.g the temperature and time the pondweed is left to photosynthesise)
6) repeat the experiment with the light source placed at different distances from the pondweed
practical for measuring the effect of temperature and CO2 on photosynthesis
1) you can use the same apparatus from “practical for showing that oxygen productions shows the rate of photosynthesis” in this experiment
2) put the test tube of pondweed into a beaker of water at a set temperature and CO2 is bubbled into the test tube
3) experiment is repeated with different temperatures of water or concentrations of CO2
why are plants important in food chains and nutrient cycles?
because they can take minerals from the soil and energy from the sun and turn it into food
what are the 3 main mineral ions that plants need for growth?
- nitrate
- phosphates
- potassium
why do plants need certain elements?
so that they can produce important compounds
where do plants get important elements to produce important compound?
they get the elements from mineral ions in the soil
what happens to plants if there aren’t enough minerals ions in the soil?
plants suffer deficiency symptoms
why do plants need nitrates?
for making amino acids and proteins. These are needed for cell growth.
what happens if a plants can’t get enough nitrate?
it will be stunted and older leaves will turn yellow
why do plants need phosphates?
for making DNA and cell membranes and they’re needed for respiration and growth.
what happens if a plants can’t get enough phosphates?
the plants will have poor growth and their older leaves are purple
why do plants need potassium?
to help enzymes needed for photosynthesis and respiration
what happens if a plants can’t get enough potassium?
plants will have poor glower and fruit growth and discoloured leaves
the 3 mineral ions (nitrate, phosphates, potassium) are needed in large amounts, but what other element is needed in a smaller amount?
magnesium
why do plants need magnesium?
it is required for making chlorophyll (needed for photosynthesis)
what happens if a plants can’t get enough magnesium?
they will have yellow leaves
what do multicellular organisms need fir transporting substances from A to B?
a transport system
what do cells in living organisms need to live?
a variety of substances (e.g plants need things like water, minerals and sugars, they also need to get rid of waste substances)
what happens to waste substances in unicellular organisms?
the substances can diffuse directly into and out of the cell across the cell membrane
why is the diffusion rate quicker in unicellular organisms?
because of the short distances substances have to travel
why in multicellular organisms direct diffusion from the outer surface would be too slow?
because substances would have to travel large distances to reach every single cell
give two examples of multicellular organisms
plants and animals
why do multicellular organisms need transport systems?
to move substances to and from individual cells quickly
where does carbon dioxide diffuse in plants?
into the leafs
what are the two systems in plants transporting substances around?
xylem tubes and phloem tubes
what does the xylem tubes transport?
water and minerals.
They carry water and minerals from the roots up the shoot to leaves in the transpiration stream
what does the phloem tube transport?
food.
It transports sugars like sucrose and amino acids from where they’re made in the leaves to other parts of the plants (translocation)
what is the movement of food substances around the plant called?
translocation
how is the movement of substances inside a xylem tube?
they all move in the same direction
how is the movement of substances inside a phloem tube?
substance come from different (opposite) direction to meet each other in a specific point
