Cells, Organs And Populations

Question 1

What does a animal cell contain?

Answer 1

Nucleus
Cytoplasm 
Mitochondria
Cell membrane 
Ribosomes

Question 2

What does a plant cell contain?

Answer 2

Everything in an animal cell
Cell wall
Permanent vacuole
Chloroplasts

Question 3

What is yeast?

Answer 3

A single celled organism, a microorganism that has a nucleus, cytoplasm and a cell membrane surrounded by a cell wall

Question 4

What is a bacterial cell?

Answer 4

A single celled microorganism, which has a cytoplasm and cell membrane surrounded by a cell wall. It’s genetic material flits in the cytoplasm as they don’t have a nucleus

Question 5

How do dissolved substances move in and out of cells?

Answer 5

By diffusion

Question 6

What kinds of molecules can diffuse through cell membranes?

Answer 6

Oxygen, glucose, amino acids and water

Question 7

What kind of substances can not diffuse through a membrane?

Answer 7

Starch and proteins

Question 8

Who are palisade leaf cells adapted for photosynthesis?

Answer 8

• packed with chloroplasts for photosynthesis, which are crammed at the top of the cell so they are nearer to light
• tall shape for a larger surface area exposed down the side of the leaf for absorbing more CO2
• thin shape means they can pack lots of them in at the top of the leaf

Question 9

How are guard cells adapted to open and close pores?

Answer 9

• kidney shape which opens and closes the stomata
• when the plants have lots of water the guard cells fill with it and become plump and turgid. This makes the stomata open so gases can be exchanged for photosynthesis
• when the plant is short of water, guard cells lose water and become flaccid making the stomata close, this helps to stop water vapour escaping
• sensitive to light and close at night to save water without losing out on photosynthesis

Question 10

How are red blood cells adapted?

Answer 10

• concave disc shale which gives a big surface area for absorbing oxygen. It also helps them pass smoothly through the capillaries
• packed with Haemoglobin (pigment which absorbs oxygen)
• no nucleus, more room for haemoglobin

Question 11

How are egg cells adapted?

Answer 11

The egg fell Contains huge food reserves to feed the embryo

-changes its membrane structure when the sperm fuses with the egg so that no more sperm can get in

Question 12

How are sperm cells adapted?

Answer 12

• enzymes in head to digest through the egg cell membrane
• streamlined head and long tail to swim to the egg
• a lot of mitochondria to provide the energy needed

Question 13

What are large multicellular organisms made up of?

Answer 13

Organ systems

Question 14

What is the process by which cells become specialised for a particular job ?

Answer 14

Differentiation

Question 15

When does differentiation occur?

Answer 15

During the development of a multicellular organism

Question 16

Specialised cells form …

Answer 16

Tissues, which form organs, which form organ systems

Question 17

What is a tissue?

Answer 17

A group of similar cells that work together to carry out a particular function

Question 18

What is a glandular tissue?

Answer 18

A tissue which makes and secretes chemicals like enzymes and hormones , e.g. Digestive juices

Question 19

What is an epithelial tissue?

Answer 19

A tissue which covers some parts of the body

Question 20

What is an organ?

Answer 20

A group of different tissues that work together to perform a certain function

Question 21

What is an organ system?

Answer 21

A group of organs working together to perform a particular function

Question 22

Name the parts and functions of the digestive system

Answer 22

1. Glands (salivary glands and pancreas) produce digestive juices
2. The stomach and small intestine, digest food
3. Liver, produces bile
4. Small intestine which absorbs soluble food molecules
5. Large intestine which absorbs water from undigested food, leaving faeces

Question 23

What does the digestive system do?

Answer 23

Exchanged materials with the environment by taking in nutrients and releasing substances (e.g. Bile)

Question 24

What is the equation for photosynthesis ?

Answer 24

Carbon dioxide+ water =(sunlight + chlorophyll)= glucose + oxygen

Question 25

What are the plant organs?

Answer 25

Stems, roots and leaves

Question 26

What are the tissues in a leaf?

Answer 26

• mesophyll tissue, where photosynthesis occurs in the plant
• xylem and phloem, transport things like water and mineral ions around the plant
• epidermal tissue- covers whole of the plant

Question 27

How are chloroplasts used for photosynthesis?

Answer 27

They contain a green substance called chlorophyll which absorb sunlight and used its energy to convert carbon dioxide and water into glucose. Oxygen is produced as by-product

Question 28

What factors affect the rate of photosynthesis ?

Answer 28

Light, CO2, temperature and water

Question 29

What is a limiting factor?

Answer 29

Stopping photosynthesis from happening any faster

Question 30

What is one way to control the amount of CO2 in photosynthesis?

Answer 30

Dissolve different amounts of sodium hydrogencarbonate in the water which gives off CO2

Question 31

How is temperature a limiting factor of photosynthesis?

Answer 31

If the temperature is too low, the enzymes needed for photosynthesis work more slowly. If the plant gets too hot, the enzymes needed will become denatured

Question 32

How are greenhouses used for photosynthesis?

Answer 32

They trap the suns heat, and make sure the temperature doesn’t become limiting
In winter, heaters can be used and in summer, shares and ventilation may be used to cool things down
Artificial sunlight can be used
Amount of CO2 can be increased by using a paraffin heater
Keeping plants enclosed keeps them away from pests and disease

Question 33

How do plants use glucose for respiration?

Answer 33

Glucose is used to release energy which enables them to convert the rest of the glucose into other useful substances, which can be used to build new cells and for growth

Question 34

How can glucose be used to make cell walls?

Answer 34

It is converted into cellulose for making strong cell walls

Question 35

How can glucose be used for making proteins?

Answer 35

It is combined with nitrate ions to make amino acids, which are then made into proteins

Question 36

How do plants use glucose to store it as starch?

Answer 36

Glucose is turned into starch and stored in the roots stems and leaves, ready for use when photosynthesis isn’t happening (winter).

Question 37

What affects where an organism is found?

Answer 37

• temperature
• availability of water
• availability of oxygen, CO2, nutrients
• amount of light

Question 38

How do you measure how common an organism is in two samples areas?

Answer 38

By using quadrats
Quadrat is placed at a random point within the first sample area and all organisms within the quadrat are counted. This is repeated. The mean number of organisms per quadrat is then worked out within the first sample area. This is repeated in the second sample area

Question 39

How do you measure how the distribution of an organism changes across an area?

Answer 39

By placing quadrats along a transect
Mark out a line in the area you want to study using a tape measure. Collect date along the line by counting all the organisms that touch the line. OR place quadrats next to eachother along the line or at regular intervals and count the organisms inside

Question 40

How do you work out population size?

Answer 40

Work out the mean number of organisms per m^2. Then multiply the mean by the total area