Stem Cells and cancer

Question 1

What Is a somatic cell?

Answer 1

any cell in the human body that is not involved in reproduction

Question 2

how many chromosomes do somatic cells have?

Answer 2

46

Question 3

are somatic cells diploid or haploid

Answer 3

diploid

Question 4

what does diploid mean

Answer 4

A cell containing two complete sets of chromosomes, one from each parent

Question 5

what is a germline cell

Answer 5

the cells involved in reproduction

Question 6

what are the male and female gametes

Answer 6

male - sperm
female - ova

Question 7

are gametes haploid or diploid

Answer 7

haploid

Question 8

how does one diploid germline cell become four haploid gametes

Answer 8

• diploid germline cells divide by mitosis to produce two identical diploid germline cells
• these then undergo meiosis to produce four haploid gametes

Question 9

how many chromosomes does a haploid gamete contain

Answer 9

23

Question 10

what happens during the two divisions of meiosis

Answer 10

first division - separation of homologous chromosomes

second division - separation of the chromatids

Question 11

what is fertilisation?

Answer 11

the process by which the male and female gametes fuse to form a zygote

Question 12

explain some of the differences between mitosis and meiosis

Answer 12

• mitosis produces genetically identical daughter cells whereas meiosis produces genetically varied daughter cells
• daughter cells are diploid following mitosis whereas the daughter cells are haploid following meiosis
• 2 daughter cells are produced in mitosis whereas 4 daughter cells are produced in meiosis

Question 13

what is cellular differentiation?

Answer 13

When a cell expresses specific genes to produce proteins characteristic of a certain type of cell.

it is the process by which an unspecialised cell becomes altered to perform a specialised function

Question 14

what are stem cells

Answer 14

unspecialised cells which can either replicate themselves or differentiate into a range of different cell types

Question 15

what are the two types of stem cell

Answer 15

embryonic stem cells and tissue stem cells

Question 16

which of the stem cell types are pluripotent

Answer 16

embryonic stem cells

Question 17

what does pluripotent mean

Answer 17

all of the genes in an embryonic stem cell can be expressed, giving rise to any type of cell

Question 18

are tissue stem cells multipotent or pluripotent

Answer 18

multipotent

Question 19

what does multipotent mean

Answer 19

the cell can differentiate into any of the types of cell of the same tissue type

Question 20

where are blood stem cells found in adults

Answer 20

bone marrow

Question 21

examples of cell types which a blood stem cell can differentiate into

Answer 21

• red blood cell
• platelet
• phagocyte/lymphocyte ( white blood cells)

Question 22

how are stem cells used for research?

Answer 22

they are used as model cells to study how diseases develop for drug testing

Question 23

what three ways are stem cells used therapeutically

Answer 23

• corneal repair
• skin grafting for burns
• bone marrow transplantation

Question 24

what are the ethical issues surrounding stem cells

Answer 24

• the extraction of human embryonic stem cells for research purposes results in the destruction of human embryos
• at what stage in development should an embryo be regarded as a person?

Question 25

what is a tumour

Answer 25

A growth caused by a group of cancerous cells clumping together

Question 26

what is the meaning of a cell becoming cancerous?

Answer 26

the cell grows and divides uncontrollably because they do not respond to regulatory signals

Question 27

what are the two types of tumour

Answer 27

benign and malignant

Question 28

what does benign mean

Answer 28

harmless and do not spread to other parts of the body

Question 29

what does malignant mean

Answer 29

a tumour which grows quickly, and can spread to other parts of the body via the bloodstream

Question 30

how does a secondary tumour form

Answer 30

when cancer cells fail to attach to each other they can travel through the bloodstream to other parts of the body where they may form a secondary tumour

Question 31

what are some risk factors for developing cancer

Answer 31

- genetic mutation - exposure to harmful chemicals or ionising radiation - smoking - UV radiation from the sun - poor diet