Cells And Control

Question 1

What does mitosis produce

Answer 1

2identical daughter cells

Question 2

What are the 4 stages of mitosis

Answer 2

Interphase, prophase, metaphase, anaphase, telophase, cytokinesis

Question 3

What happens at interphase

Answer 3

Before the cell divides it has to grow to increase the number of mitochondria & ribosomes. Then in duplicates it dna - copied dna forms x-shaped chromosomes

Question 4

What happens at each stage of mitosis

Answer 4

1-prophase) The chromosomes get condense (shorter&fatter). The membrane around the nucleus breaks down and the chromosomes lie free in cytoplasm
2-metaphase) The chromosomes line up at the centre of the cell
3-anaphase) Spindle fibres pull the chromosomes apart. Then the chromatids are pulled to opposite ends of the cell
4-telophase) Membranes form around each of the sets of chromosomes, these become the nuclei of the 2 new cells - nucleus has divided

Question 5

What happens before telophase ends

Answer 5

Cytokinesis

Question 6

What is cytokinesis

Answer 6

When cytoplasm and cell membrane divide to form 2 separate cells

Question 7

How to calculate the number of cells they’ll be after after divisions

Answer 7

2(n) (n=number of divisions by mitosis)

Question 8

What happens at mitosis and cytokinesis

Answer 8

Once the dna has been copied, it’s ready for mitosis

Question 9

What is mitosis

Answer 9

a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.

Question 10

How is cancer caused

Answer 10

Uncontrolled cell divisor - if there is a change in the gene that controls mitosis the cell could start to divide uncontrollably, which can result in a mass of abnormal cells = tumor, if the tumor invades and destroys surrounding tissues =cancer

Question 11

What is a diploid cell

Answer 11

A cell with 2 copies of each chromosome

Question 12

What do organisms use mitosis for

Answer 12

To asexually reproduce

Question 13

What’s cell differentiation

Answer 13

The process by which a cell changes to become specialised for its job

Question 14

What is cell elongation

Answer 14

Where a plant cell expands, making the cell bigger -plant grow

Question 15

What is most cell division used for in adults

Answer 15

Repair - cells divide to replace old or damaged cells

Question 16

Where does cell division happen in a plant?

Answer 16

I’m the tips of the roots and shoots and meristems

Question 17

What are stem cells

Answer 17

Undifferentiated cells

Question 18

How do cells become specialised

Answer 18

They differentiate

Question 19

Where are stem cells found

Answer 19

Early human embryos

Question 20

What can embryonic stem cells do

Answer 20

Divide and produce any kind of cells

Question 21

What are stem cells really important for

Answer 21

Growth and development of organisms

Question 22

Where are stem cells found in adults

Answer 22

Bone marroe

Question 23

What are adult stem cells used to do in animals

Answer 23

Replace damaged cells e.g to make new skin or blood cells

Question 24

In plants, where are the only cells that divide by mitosis found

Answer 24

In plant tissues called meristems

Question 25

Where are meristem tissues found

Answer 25

In areas of a plant that are growing e.g. tips, roots, shoots

Question 26

What do meristems produce

Answer 26

Unspecialised cells that act like embryonic stem cells

Question 27

What do the unspecialised cells in plants go on to form

Answer 27

Xylem, phloem

Question 28

How is sickle cell anemia cured

Answer 28

With a bone marrow transplant

Question 29

What are the 3 potential risks about using adult stem cells to cure some diseases

Answer 29

Tumour development, disease transmission, rejection

Question 30

What is tumour development

Answer 30

When stem cells divide very quickly, if scientists are unable to control the rate at which the transplanted stem cells divide, a tumour may develop inside the patient

Question 31

What is disease transmission

Answer 31

Viruses live inside cells, if donor cells are infected with a virus and are undetected the virus could be passed on to the patient and make them sicker

Question 32

What is rejection

Answer 32

If the transplanted cells aren’t grown using the patients own stem cells, the patients body may recognise them as foreign and trigger an immune response to try get rid of them. The patient can take drugs to suppress this, but that can make them susceptible to diseases

Question 33

What is the ethical issue raised about using embryonic stem cells

Answer 33

Some people argue that using embryonic stem cells shouldn’t be used for experiments because each one is a potential life

Question 34

What can you use stem cells for

Answer 34

To create specialised cells to replace those which have been damaged by disease or injury

Question 35

What is the nervous system made up of

Answer 35

Neurones(nerve cells)

Question 36

What are sensory receptors

Answer 36

Groups of cells that can detect a change in your environment (a stimulus)

Question 37

What happens when a stimulus is detected by receptors

Answer 37

The info is converted to a nervous(electrical) impulse and sent alone sensory neurones to the CNS (brain and spinal chord)

Question 38

What does the CNS do

Answer 38

Coordinates the response

Question 39

How do impulses travel

Answer 39

Through the CNS along relay neurones

Question 40

What does the cns do

Answer 40

Sends info to an effector (muscle/gland) along a motor neurone

Question 41

What is reaction time

Answer 41

The time it takes you to respond to a stimulus

Question 42

What do all neurones have

Answer 42

A cell body with a nucleus

Question 43

What does the cell body have

Answer 43

Extensions that connect to other neurones

Question 44

What do dendrites and dendrons do

Answer 44

Carry nerve impulses towards the cell body

Question 45

What do axons do

Answer 45

Carry nerve impulses away from the cell body

Question 46

What are some axons surrounded by

Answer 46

Myelin sheath

Question 47

What does myelin sheath do

Answer 47

Acts as an electrical insulator speeding up the electrical impulse

Question 48

What is the structure of a sensory neurone

Answer 48

One long dendron, one short axon

Question 49

What does a sensory neurone (dendron) do

Answer 49

Carried nerve impulses from receptor cells to cell body which is located in the middle of the neurone

Question 50

What does a sensory neurone (axon) do

Answer 50

Carries nerve impulses from cell body to CNS

Question 51

What is the structure of a motor neurone

Answer 51

Many short dendrites, one long axon

Question 52

What is the function of the motor neurone (short dendrites)

Answer 52

Carry nerve impulses from cns to cell body

Question 53

What is the function of motor neurone (long axon)

Answer 53

Carries nerve impulses from cell body to effector cells

Question 54

Structure of relay neurone

Answer 54

Short dendrites, axon

Question 55

Function of relay neurone

Answer 55

Relay neurons are found in the brain and spinal cord and allow sensory and motor neurons to communicate.

Question 56

What is a synapse

Answer 56

The connection between 2 neurones

Question 57

What are nerve signals transferred by

Answer 57

Chemical called neurotransmitters which diffuse across the gap

Question 58

What are reflexes

Answer 58

Automatic responses to stimuli