CELL DIVOSION

Question 1

What are chromosomes made up of?

Answer 1

DNA molecules combined with proteins, contain genes with instructions for protein synthesis.

Question 2

What is a Gene?

Answer 2

A section of DNA which codes for a protein.

Question 3

How many chromosomes are found in the nucleus of human body cells?

Answer 3

46

Question 4

How many chromosomes are found in the nucleus of gametes?

Answer 4

23

Question 5

How many chromosomes arranged in the nucleus of a body cell?

Answer 5

Arranged in pairs, 46 chromosomes from 23 pairs.

Question 6

What are the three main stages of The Cell Cycle?

Answer 6

1)Replication of DNA and synthesis of organelles
2) Mitosis
3) Division of cell

Question 7

Why is mitosis important?

Answer 7

Produces identical cells with the same info, produces additional cells for growth and repair.

Question 8

Describe the first stage of the cell cycle

Answer 8

Longest Stage - cells grow and increase in mass, replicate DNA and synthesise more organelles (eg. Mitochondria, ribosomes)

Question 9

Describe the second cell of the cell cycle

Answer 9

Each chromosome in a pair is pulled to opposite poles of the cell, then the nucleus divides.

Question 10

Describe the third stage of the cell cycle

Answer 10

The cytoplasm and cell membrane divide - two identical daughter cells are produced.

Question 11

What is a stem cell?

Answer 11

An unspecialised cell which is capable of differentiating into other cell types and of self renewal.

Question 12

What is the function of stem cells in embryos?

Answer 12

Embryonic stem cells can replicate themselves and differentiate into many other types of cells, they can also treat things such as paralysis no diabetes by replacing damaged cells.

Question 13

What is the function of stem cells in adult bone marrow?

Answer 13

Adult stem cells can differentiate into several cell types to replace dead or damaged tissues, bone marrow stem cells can form many different types of blood cell.

Question 14

What is the function of stem cells in plant meristems?

Answer 14

Meristem stem cells retain the ability to differentiate into any type of plant cell throughout their life span - they can differentiate into any cell which the pant requires.

Question 15

What are the advantages of cloning plants using meristem stem cells?

Answer 15

Can prevent rare plants from going extinct, can create large numbers of plants with a favourable characteristic, can produce identical plants for research.

Question 16

What are the issues associated with the use of embryonic stem cells?

Answer 16

Many are sourced from aborted embryos some people have ethical or religious objections, developments of stem cell therapies is slow expensive and difficult, adult stem cells infected with viruses could transmit it to the patient, is the donor stem cells do not have a similar genetic makeup an irregular immune response could be triggered.