BIOLOGY 9B

Question 1

How do plants make their own food?

Answer 1

They make their own food using carbon dioxide and water

Question 2

What are the reactants (raw materials) of photosynthesis?

Answer 2

Carbon dioxide an water

Question 3

What are the products for photosynthesis?

Answer 3

Sugar, called glucose, and oxygen

Question 4

What is the word equation for photosynthesis?

Answer 4

carbon dioxide + water -> glucose + oxygen

Question 5

What is needed to make photosynthesis happen?

Answer 5

Light

Question 6

What do chlorophyll do, where is it found?

Answer 6

Chlorophyll are found inside chloroplasts in many plant cells and what it does is it captures the energy transfered by light.

Question 7

What happens to the energy that has been captured by the chlorophyll?

Answer 7

This energy is stored in the glucose

Question 8

How can photosynthesis vary?

Answer 8

Photosynthesis can occur at diff. rates, these are the variants:

• Light (less light, slower)
• Raw material (less raw material, slower)

Question 9

What is the scientific name for the variable that slows spwn the rate (speed) ?

Answer 9

Limiting Factor

Question 10

What does every living cell in a plant need and for what?

Answer 10

They need a supply of glucose for energy. This is because energy is needed to make the plant grow and to make new substances.

Question 11

What does aerobic respiration release?

Answer 11

It releases the chemical energy stored in the glucose

Question 12

What is the word equation for aerobic respiration (respiration)?

Answer 12

Glucose + oxygen -> carbon dioxide + water

Question 13

What happens with photosynthesis in a plant?

Answer 13

Photosynthesis only happens when there is light whilst respiration happens all the time, due to this, during the day a plant produces more oxygen from photosynthesis than it needs for respiration and so oxygen is given off.

Question 14

Where is glucose carried? For what?

Answer 14

Glucose is carried to all parts of a plant in the form of sugars dissolved in water

Question 15

What do phloem vessels do??

Answer 15

Phloem vessels, which are made of chains from living phloem cells, carry the sugar solution. This is how roots get glucose for respiration.

Question 16

What do roots also need??

Answer 16

They also need oxygen, which they get it from the soil, so therefore if the soil becomes flooded or waterlogged, toots cannot get enough oxygen and so the plant can die

Question 17

What do plants need to stay healthy, give an example?

Answer 17

They need chemical elements from mineral salts to stay healthy, for example, plant root cells need to have potassium to absorb water properly

Question 18

What happens to plants that live in soils that are low in mineral salts?

Answer 18

They get their mineral solts from insects.
Eg: Venus flytraps have leaves with specialised cells that form ‘trigger hears”. If an insect touches a hair more than once, a signal is sent to cells which then change shape and shut the trap. After this enzymes digest the insect, releasing mineral salts.

Question 19

How are roots adapted to their function?

Answer 19

They are adapted to their function by being branched and spread out, helping them to get water from a large volume of soil.
They also have root hair cells to give them a large surface area so they can quickly absorb water.

Question 20

What happens to the water once it has been absorbed by the roots.

Answer 20

Once absorbed, water passes to xylem vessels in the centre of the root.

Question 21

How are xylem vessels formed? What do they do?

Answer 21

These long tubes are formed when chains of xylem cells become hollow, as they die. The tubes carry water and dissolved mineral salts to the leaves.

Question 22

Give some of the reasons water is needed for?

Answer 22

• Photosynthesis
• Keeping leaves cool
• Filling up cells to keep them expanded and firm.
  If there is too little water, the cells sag and the plants droops/ wilts (leaves fall)

Question 23

What do the leaves on many plants have, for what?

Answer 23

They are broad and have a large surface area for trapping light.

Question 24

How are the leaves in a plant often arranged?

Answer 24

They are often arranged on a plant so that the upper leaves do not shade the lower ones to much

Question 25

What is there inside a leaf?

Answer 25

There are different layers of tissue

Question 26

What do the epidermis cells do?

Answer 26

Epidermis cells produce a waxy layer (cuticle) to stop the leaves losing too much water.

Question 27

What do the palisade cells do, how are they adapted to their function?

Answer 27

They are adapted to their funtion by containing lots of chloroplasts (where photosynthesis occurs).

Question 28

What do the chloroplasts do depending on the light?

Answer 28

The chloroplasts move nearer to the surface of the leaf in dim light. They move in the opposite direction in bright light to stop them being damaged.

Question 29

Name three limiting factors in photosynthesis and their function?

Answer 29

1) Light intensity= If there is more light, the rate of photosynthesis will increase up to certain point
2) Temperature= If its really cold, the rate of photosynthesis will decrease
3) CO2 Levels= If there is not enough carbon dioxide, the rate of photosynthesis will decrease

Question 30

What are staomata?

Answer 30

Stomata are small holes in a leaf that are opened and closed by guard cells. Stomata are shut at night and open when it is light
Gases, such as CO2, enter and leave the leaf by difussion through open stomata.
As leaves are thin, CO2 doesn’t have to diffuse very far into a leaf before getting to the cells

Question 31

What do plants lose through stomata?

Answer 31

Plants also lose water and oxygen through stomata, and this swapping of different gases is caleed gas exchange

Question 32

What do farmers grow?

Answer 32

Farmers grow different crops to produce a vast range of different substances obtained from plants.

Question 33

What do all the substances found in a plant depend on?

Answer 33

They depnd on the glucose from photosynthesis for their production

Question 34

What are lipids?

Answer 34

Plants make many different lipids. Lipids are a group of insoluble substances that include fats and oils.

Question 35

What does the cuticle of a plant contain?

Answer 35

The cuticle of a plant leaf contains lipids to make it waterproof

Question 36

Where are fats and oils often found?

Answer 36

They are found in plant seeds, where they are used as energy stores. They can also be found in the flesh of some fruits, such as avocado, to encourage animals to eat the fruits and therefore disperse the seeds.

Question 37

What can happen to the glucose molecules made in photosynthesis?

Answer 37

They can be linked together to form a polymer called starch. This molecule stays in the chloroplasts until photosynthesis stops. Then the starch is broken down into small sugar molecules and transported to phloem vessels, in which they are carried to other parts of the plant

Question 38

What happens in some plants to the sugar that has been broken down?

Answer 38

In some plants, these sugars are converted back into starch in storage organs, such as potatoes , or seeds. The sugars are also used to make another polymer named cellulose, which is used to make plant cell walls

Question 39

What do you use to test for starch

Answer 39

You can test for starch by using iodine solution, which turns the starch a blue/black colour

Question 40

What are proteins?

Answer 40

Proteins are also a type of polymer. They are long chains of molecules called amino acids (of which there are many different kinds). However, to make amino acids a plant needs a good supply of mineral salts called nitrates

Question 41

What are the functions of proteins?

Answer 41

Proteins have many functions. All enzymes are proteins, such as those needed for photosynthesis and respiration. Seeds also contain a store of protein to supply amino acids to make new proteins as a seedling starts to grow.

Question 42

What do seeds contain?

Answer 42

Seeds contsin a store of all the resources that a new seedling will need to grow, until its leaves can opeen and start to photosynthesise.

Question 43

What is the process that occurs during germination?

Answer 43

1) Water and oxygen enters
2) The entry of water allows molecules to move around so that reactions can occur. It also triggers the release of enzymes
3) The enzymes digest the starch to glucose. Enzymes work faster if it is warmer
4) The glucose enters the embryo, allowing it to respire and grow

Question 44

What do fertilisers contain?

Answer 44

Fertilisers contain mineral salts, such as potassium, phosphates and nitrates

Question 45

What do farmers use?

Answer 45

Farmers use artificial fertilisers and natural ones such as manure (animal waste).

Question 46

What are decomposers?

Answer 46

Decomposers are microorganisms that break down the manure and release the mineral salts.

Question 47

What is a pest?

Answer 47

A pest is an organism that damages crops

Question 48

What do pesticides, fungicides, insecticides and herbicides kill?

Answer 48

Pesticides= kill pests
Fungicides= kill fungi that cause plant diseases
Insecticides= kill insect pests
Herbicides= kill weeds, which compete for the crop plants for water, light and mineral salts. Modern herbicides are selective as they kill weed plants with broad leaves but not crop plants with narrow leaves (wheat)

Question 49

What can happen to fertilisers?

Answer 49

Fertilisers can wash into rivers and lakes. The phosphates and nitrates cause fast growth of algae and plants, which block out light causing a lot of them to die. As a decomposer bacteria break down the dead material, they use up the oxygen in the water, causing fish to die

Question 50

What happens to some insecticides?

Answer 50

Some insecticides are persistent (do not break down in the environment).

Question 51

What might happen to top predators in a food chain?

Answer 51

Predators in a food chain may eat many animals containing small amounts of insecticide meaning that the top predator gets a large amount of the substance, which may harm it.

Question 52

What happens with selective herbicides?

Answer 52

Selective herbicides only kill plants that have broad leaves and so a crop, like wheat, is not affected. On the other hand, many plants in hedges have broad leaves and are killed

Question 53

What can happen if farmers plant the sae variety of crop?

Answer 53

Since all the plants are identical, if one gts a disease then all the others will. A new disease can wipe out the entire crop

Question 54

Wha happens if a single crop variety id planted over a large area?

Answer 54

The biodiversity will be reduced, causing the food webs to become smaller and therefore if a disaster hits the area it takes much more time to recover than if there was a greater biodiversity in the area.

Question 55

What is reduced from the atmosphere when plants photosynthesise?

Answer 55

Carbon dioxideis removed by plants when they photosynthesise. Carbon is ‘stored’ in trees but the carbon in crops is soon released back into the atmosphere, when the crops are used for food or fuel.

Question 56

What has happened due to the burning of fossil fuels and destruvtion of forests?

Answer 56

Due to this, the amount of carbon dioxide in the atmosphere has been increasing for the las 200 years. This extra release is thought to be causing global warming.

Question 57

What does the carbon cycle show?

Answer 57

The carbon cycle shows the processes by which carbon dioxide is removed and released