Cells

Question 1

What does the nucleus do?

Answer 1

Contains DNA and controls the activities of the cell

Question 2

What does the cell membrane do?

Answer 2

Controls what goes in and out of the cell

Question 3

What does the mitochondria do?

Answer 3

Where aerobic respiration occurs-releases energy

Question 4

What do the ribosomes do?

Answer 4

Where proteins are made via protein synthesis

Question 5

What does the cytoplasm do? (Plant)

Answer 5

Where chemical reactions happen

Question 6

What does the chloroplast do? (Plant)

Answer 6

Contains chlorophyll to absorb sunlight. Where photosynthesis happens

Question 7

What does the vacuole do? (Plant)

Answer 7

Keeps the cell rigid supports it and stores sap

Question 8

What does the cell wall do? (Plant)

Answer 8

Made of cellulose for support and to stop the cell from bursting

Question 9

What does the chromosonal DNA do? (Bacteria)

Answer 9

Controls most of cell activities

Question 10

What does plasmid DNA do? (Bacteria)

Answer 10

Controls some of the cell activities

Question 11

What does the flagella do? (Bacteria, tail)

Answer 11

Propels to move the cell

Question 12

What does the slime coat do? (Bacteria)

Answer 12

Stops the cell drying out

Question 13

What does the acrosome do? (Sperm, head)

Answer 13

Contains enzymes and it breaks down the eggs jelly coat to fertilize it

Question 14

What does the cytoplasm do? (Egg cell)

Answer 14

It contains lots of nutrients for the fertilized egg to develop

Question 15

What is mitosis?

Answer 15

Mitosis is the production of 2 genetically identical diploid daughter cells

Question 16

What are the stages of mitosis in order?

Answer 16

Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis

Question 17

What happens in the interphase?

Answer 17

New sub-cellular structures are made and the DNA replicates

Question 18

What happens in the prophase?

Answer 18

Nucleus breaks down and spindle fibres begin to form

Question 19

What happens in the metaphase?

Answer 19

Spindle fibres attach to the chromosones and the chromosones line up against the equator of the cell

Question 20

What happens in the anaphase?

Answer 20

The spindle fibres shorten and pull the chromosones apart to the poles of the cell

Question 21

What happens in the telophase?

Answer 21

A membrane forms around each set of chromosones to form 2 new nuclei

Question 22

What happens in cytokinesis?

Answer 22

New cell surface membranes form to seperate the 2 genetically identical diploid daughter cells

Question 23

How is there growth in plants?

Answer 23

Cell division by mitosis in shoot and root tips
Elongation-cells in shoots and root tips get longer
Differentiation-meri stem cells can differentiate into different cells

Question 24

What are the characteristics of ciliated epithial cells?

Answer 24

Have cilia (hair like structures) that waft the fertilised egg towards the womb
Contain a lot of mitochondria to release a lot of energy from aerobic respiration to move the cilia

Question 25

Facts about electron microscopes | What does higher resolution mean?

Answer 25

Higher magnification and resolution than a light microscope Higher resolution means that we can see in more detail

Question 26

What happens to an enzyme when it reaches optimum temperature?

Answer 26

The enzymes active site shape changes so much that it denatures the enzyme and so the substrate can no longer bind to it and the reaction stops

Question 27

What is diffusion?

Answer 27

Diffusion is the passive movement of molecules from an area of high concentration to an area of low concentration.

Question 28

What is active transport?

Answer 28

The movement of molecules from an area of low concentration to an area of high concentration using energy from respiration so transport proteins can carry the molecules across the membrane

Question 29

What is osmosis?

Answer 29

Passive movement of water molecules from an area of high concentration to an area of low concentration across a partially permeable membrane

Question 30

How many chromosones in a haploid cell?

Answer 30

23

Question 31

How many chromosones in a diploid cell?

Answer 31

46

Question 32

Why is mitosis important to organisms

Answer 32

Asexual reproduction Growth Repair

Question 33

How is there growth in animals

Answer 33

Cell divison by mitosis | Differentiation - only stem cells can differentiate into other cell types

Question 34

Facts about stem cells

Answer 34

They are undifferentiated not specialised Can divide by mitosis to make specialised cells Embrionic stem cells can become almost anything Adult stem cells only have a limited range of cell types

Question 35

What are the benefits to embrionic stem cells?

Answer 35

Easy to collect and can treat more diseases

Question 36

What are the drawbacks of embrionic stem cells?

Answer 36

Ethical issues of destroying embryos to get stem cells | Stem cells could get rejected by the bodys immune system

Question 37

What are the benefits of adult stem cells

Answer 37

No ethical issues

Question 38

What are the drawbacks of adult stem cells?

Answer 38

Difficult to collect from the body | Can only treat a range of diseases

Question 39

What is the central nervous system (CNS) made of?

Answer 39

Brain and spinal cord

Question 40

What are the 3 types of neurones?

Answer 40

Sensory neurone Relay neurone Motor neurone

Question 41

What does the sensory neurone do?

Answer 41

Carry impulses from the receptors to the CNS

Question 42

What does the myelin sheath do?

Answer 42

Speeds up transmission of electrical impulse

Question 43

What does the relay neurone do?

Answer 43

Carry impulses from the CNS to the motor neurones (relay neurones make up the brain and spinal cord)

Question 44

What does the motor neurone do?

Answer 44

Carry impulses from the relay neurone to the effectors

Question 45

What is a synapse

Answer 45

Synapes are gaps between neurones that convert electrical energy from the impulse in the neurone into chemical energy in the synapse. Chemicals called neurotransmitters diffuses across the synapse and cause a new electrical impulse in the next neurone

Question 46

What happens in a reflex arc?

Answer 46

A stimulus is sensed by a receptor which sends an electrical impulse up the sensory neurone. The impulse is converted to a chemical signal at the synapse. Neurotransmitters diffuse across the synpase and pass the signal to the relay neurone (in the spinal cord). The signal crosses another synapse to reach the motor neurone which takes it to the effector, which produces a response.

Question 47

What happens in meiosis?

Answer 47

Makes 4 genetically different haploid gametes | The cytoplasm divides twice