B2A cells, organs and populations

Question 0

What organelles are found in plant cells only and their functions?

Answer 0

Cell wall: cellulose for support
Chloroplasts: contain chlorophyll for photosynthesis
Vacuole: contains cell sap

Question 1

For each organelle state it’s function

Answer 1

Mitochondria: energy release during respiration
Nucleus: controls cell activity-holds genetics
Cell membrane: controls what goes in/out of cell
Cytoplasm: where most cell reactions happen
Ribosomes - proteins are made

Question 2

Chloroplast/chlorophyll - what’s the difference?

Answer 2

Chloroplast is the organelle structure

Chlorophyll is the green pigment

Question 3

What is a specialised cell?

Answer 3

A cell that’s structure is linked to its function - specific to its job

Question 4

Examples of specialised cells

Answer 4

Fat cells- large cytoplasm to stir lots of fat
Root hair cell- large surface area to increase rate of water absorption
Yeast cell - animal cell without mitochondria or ribosomes
Bacterial- cell membrane, cell wall, cytoplasm and genetic material floats around as it has no nucleus

Question 5

Why do cells have wiggly surfaces?

Answer 5

To increase surface area for absorption

Question 6

What is diffusion?

Answer 6

The movement of gas or dissolved substances from an area of high concentration to an area of lower concentration, down the concentration gradient until equilibrium

Question 7

What causes diffusion?

Answer 7

Passive - no energy required: relies on molecules moving randomly due to the energy they have

Question 8

What makes diffusion quicker?

Answer 8

The larger the concentration gradient the faster diffusion

Question 9

Examples of diffusion

Answer 9

Oxygen into cells body from the blood to supply respiration

Carbon dioxide into actively photosynthesis cells

Question 10

Problem with multicellular organisms?

Answer 10

Exchange ( including diffusion ) is difficult due to large number of cells

Question 11

How is the problem overcome ( exchange surface adaptions )

Answer 11

Large surface areas

Increase concentration gradient

Question 12

Give some examples of different tissues and there functions

Answer 12

Muscular tissue- contracts to move what it is attached to
Glandular tissue- makes and secretes chemicals like enzymes and hormones
Epithelial tissue- covers some parts of the body, e.g inside the gut

Question 13

What is an organ?

Answer 13

An organ is a group of different tissues that work together to perform a certain function

Question 14

Give an example of an organ and the tissues used

Answer 14

The stomach
Muscular tissue- move stomach wall to churn up food
Glandular tissue- makes digestive juices
Epithelial tissue- covers outside/inside of the stomach

Question 15

What is an organ system?

Answer 15

An organ system is a group of organs working together to perform a particular function

Question 16

Explain the digestive system

Answer 16

1) glands ( pancreas and salivary glands) produce digestive juices
2) stomach and small intestine digest food
3) liver produces bile
4) small intestine absorbs soluble food molecules
5) large intestine absorbs water from undigested food, leaving faeces

Question 17

What tissues are used in a leaf?

Answer 17

Mesophyll tissue- where most of the photosynthesis occurs
Xylem and phloem- transport water, mineral ions and sucrose
Epidermal tissue- covers the whole plant

Question 18

What is the equation for photosynthesis?

Answer 18

Carbon dioxide + water -> sunlight / chlorophyll -> glucose + oxygen

Question 19

What are limiting factors?

Answer 19

Means that it’s stopping photosynthesis from happening faster
Not enough light
Too little carbon dioxide
The temperature has to be just right too hot it kills enzymes ( 45C )

Question 20

How can you artificially creat ideal conditions for farming?

Answer 20

1) use a green house
2) green house traps the heat, in winter use heaters, in Summer use ventilation
3) artificial light, sun goes down
4) carbon dioxide, paraffin heater
5) enclosed, free from pests/diseases

Question 21

How do plants use glucose?

Answer 21

1) respiration- releases energy to use in converting the glucose
2) making cell walls- converting into cellulose
3) making proteins
4) stored in seeds
5) stored as starch- stored in roots, stems and leaves used in winter

Question 22

What factors varies an environment?

Answer 22

Temperature 
Water
Oxygen & carbon dioxide
Nutrients
Light

Question 23

How do you work out population size?

Answer 23

Mean number of organisms per m2

Multiply the mean by the total area ( in m2 )

Question 24

How do you use a quadrat?

Answer 24

Place quadrat on the ground pick Radom section
Count all organisms in the quadrat
Repeat in other sections and work out average per quadrat
Work out mode (most common value )
Work out median ( middle value)
Repeat in second sample area
Compare the 2 means