Eukaryotic cell division-mitosis

Question 1

What is mitosis

Answer 1

The process by which a cell divides to produce two genetically identical daughter cells

Question 2

What is asexual reproduction

Answer 2

The production of genetically identical offspring from a single parent or organism

Question 3

What is sexual reproduction

Answer 3

Production of offspring that are genetically different from the parent organism or organisms by the fusing of two sex cells

Question 4

What is meiosis

Answer 4

A form of cell division in which the chromosomes of the original cell is halved, leading to the formation of the gametes

Question 5

What does eukaryotic cell division involve

Answer 5

Replicating the chromosomes that carry the genetic information.

Question 6

What is a chromosome made up of

Answer 6

A mass of coiled threads of DNA and proteins

Question 7

What are the chromosomes translucent to

What does this mean

Answer 7

Both light and electrons

This means we cannot easily see them

Question 8

What happens to the chromosome when the cell actively divides

Answer 8

The chromosome condenses becoming more dense and short

Question 9

What are histones

Answer 9

Positively charged proteins involved in the coiling of DNA to form dense chromosomes in cell division

Question 10

What is formed when the DNA winds around the histones

Answer 10

Dense clusters of DNA known as nucleotides

Question 11

What must happen in mitosis when the two cells divide

Answer 11

They must both receive a full set of chromosome ]Teh two cells have an identical set of genetic information

Question 12

What is a karyotype

Answer 12

A way of displaying an image of the chromosomes of a cell to sow the pairs of autosomes and sex cells

Question 13

How do cells divide

Answer 13

In a sequence of events known as the cell cycle

Question 14

What is the interphase

Answer 14

A period of non-division when the cells increase in mass and size, carry out normal cellular activities and replicate their DNA ready for division

Question 15

What is the interphase followed by

Answer 15

mitosis (a period of active division)

cytokinesis (when the new cells separate)

Question 16

What are the different phases of the cell cycle and describe each individual

Answer 16

1)G1-The time between the end of the previous round of the mitotic cell division
The cell assimilates material, grows and develops
G1 is very short
2)S-The stage in which the chromosomes replicate and become double-stranded chromatids
3)G2-The organelles and other materials needed for cell division are synthesized
4)M-When the cells actively divide (mitosis)
5)C-The final stage of the cell division when the new cells separate (cytokinesis)

Question 17

What is the cell cycle controlled by

Answer 17

By a number of chemical signals made in response to different genes

Question 18

What are the control chemicals in the cell cycle called

Wta happens to the control chemicals

Answer 18

small proteins called cyclins

These build up and attach to enzymes called cyclin-dependent kinases (CDKs)

Question 19

What are the stages of mitosis

Answer 19

1) Prophase
2) Metaphase
3) Anaphase
4) Telophase

Question 20

What happens during the prophase

Answer 20

By the beginning of this phase both the originals and the copies are referred to as chromatids
In this phase, the chromosomes coil up
Each chromosome consists of two daughter chromatids that are attached teach others in a region join as the centromere
The nucleolus breaks down and the centrioles begin to pull apart to form the spindle

Question 21

What happens during the Metaphase

Answer 21

During this phase:
.The nuclear membrane has broken down and the centrioles have moved to the opposite poles of the cells
.the chromatids appear to jostle about for position on the metaphase plate
.Eventuallt they line up in the middle, with each centromere-associated with a microtubule of the spindle

Question 22

What happens during the Anaphase

Answer 22

During this phase:
.The centromeres that have linked the two identical chromatids split and chromatids at as completely separate entities
.They become new chromosomes
.The chromatids from each pair are drawn towards opposite poles of the cell

Question 23

What happens during the telophase

Answer 23

During this phase:
.The spindle fibres break down
.The nuclear envelopes from around two sets of chromosomes
.The nucleoli and centrioles are also re-formed
.The chromosomes begin to unravel and become less dense and harder to see

Question 24

What happens during cytokinesis

Answer 24

.In animal cells, a ring of contractile fibres tighten around the centre of the cell rather like a belt-tightening around the sack of flour
.In plant cells, with a cellulose cell wall building up from the inside of the cell outwards.
.In both animals and plants, the end result is the same:
Two identical daughter cells are formed, which then enter interphase and begin to prepare for the next cycle of division

Question 25

What does sporulation involve

Answer 25

involves mitosis and the production of asexual spores that are capable of growing into new individuals

Question 26

What is regeneration

Answer 26

It constitutes a very dramatic form of asexual reproduction, occurring when organisms replace parts of the body that have been lost

Question 27

What is fragmentation

Answer 27

The use of mitosis to regenerate a whole organism from a fragment of the original

Question 28

What have fishermen done in order to protect oyster beds from destruction Did it work

Answer 28

They have attempted to destroy the starfish, often by chopping them up and throwing them back into the sea No, they failed miserably

Question 29

What is meant by budding

Answer 29

The production by mitosis of an outgrowth from the parent organism develops into a small independent organisms

Question 30

What eventually happens to the bud

Answer 30

It eventually becomes detached from the parent and has an independent existing

Question 31

Give an example of a cell that reproduces using budding

Answer 31

Yeast cells

Question 32

What is vegetative propagation

Answer 32

The process by which a plant forms a structure by mitosis that develops into a fully differentiated, genetically identical new plants

Question 33

Where may the new plants be propagated

Answer 33

From the stem, leaf, bud or root of the parents

Question 34

What kind of division is involved in new plant structures

Answer 34

Only mitotic cell division

Question 35

What does vegetative propagation often involve

Answer 35

Often involves perennating organs

Question 36

who is vegetative propagation easily exploited by

Answer 36

By human gardeners to produce new plants

Question 37

What is an advantage of the new plant's structure

Answer 37

The new plants are all clones that will have exactly the same characteristics as their parents

Question 38

Farmers induce fragmentation artificially when cutting. Describe this process

Answer 38

This involves taking a small piece of a plant and planting it to grow on and develop by mitosis into another entire identical plant

Question 39

Why is asexual reproduction common even in complex plants

Answer 39

They maintain areas of unspecialised dividing cells throughout their life

Question 40

What does mitosis play a vital role in

Answer 40

Growth

Question 41

What is the biological definition for growth

Answer 41

A permemant increase in the number of cells,mass or size of organism

Question 42

What are the three distinct aspects for growth

Answer 42

cell division, assimilation and cell expansion

Question 43

What is the basis of cell growth

Answer 43

cell division or mitosis

Question 44

What two measurements of growth are important

Answer 44

scientifically and medically

Question 45

What factors affect growth

Answer 45

Genetic makeup, food availability, temperature and light intensity

Question 46

What is the best and most commonly used measure of growth

Answer 46

Mass

Question 47

What type of mass is the most accurate way to measure growth

Answer 47

Dry mass as water content in the body varies

Question 48

What is dry mass

Answer 48

The mass of the body of an organisms when all the water content is removed

Question 49

What is one major drawback of dry mass

Answer 49

If you remove all the water from an organism you will kill it so you will not be able to measure further growth

Question 50

What method is used in order to gather results for dry mass of organisms Does this work for all organisms

Answer 50

Grow a large samples of genetically identical organisms under similar conditions and then take random samples and dry them to a constant dry mass No,only works for some organsms eg:bacteria palnyts and fungi but is useless for animals

Question 51

What do scientists use to measure growth in animals

Answer 51

height and wet mass which isnt as accurate

Question 52

What do growth curves show

Answer 52

Shows growth throughout the life of an organism

Question 53

How des the growth curve look in most organisms

Answer 53

After an initially slow start theres a rapid period of growth until maturity is reached, when growth is slowed down or stopped

Question 54

When do animals stop growing

Answer 54

After they have matured

Question 55

What kind of growth do plants undergo

Answer 55

continuous growth

Question 56

How do insects grow

Answer 56

In a series of moults

Question 57

Do all parts of an organism grow at the same speed

Answer 57

No different parts of organisms grow at different rates

Question 58

Where does mitosis take place in plants

Answer 58

In the region known as the meristem

Question 59

What is a meristem

Answer 59

The region of mitosis and growth in a plant shoot or root

Question 60

What do plant cells do after the divide

Answer 60

They absorb water into their vacuoles and elongate rapidly before the cellulose cell wall becomes more rigid

Question 61

Does mitosis stop when the animal cell stop growing

Answer 61

NO because mitosis is needed to repair damaged cells