Division and differentiation in human cells

Question 1

Somatic cell

Answer 1

any cell in body other than cells involved in reproduction

Question 2

how do somatic cells divide

Answer 2

mitosis

Question 3

Germline cell

Answer 3

Gametes and the stem cells that divide to form gametes

Question 4

How do germline cells divide

Answer 4

Mitosis to produce more germline cells to maintain diploid chromosome number 23 pairs homologous chromosomes

or

Meiosis to produce haploid gametes - haploid 23 single chromosomes

Question 5

Fertilisation

Answer 5

Created by fusion of 2 nuclei of gametes to form zygote

Question 6

In meiosis

Answer 6

copies of genetic information made

cell divides twice to form 4 gametes, each with single set of chromosomes

all gametes are genetically different from each other, they show variation

Question 7

differentiated

Answer 7

cells express specific genes that characterise a certain type of cell

only produces the proteins characteristic for that type f=of cells

Question 8

Stem cells

Answer 8

continuously undergo cell division

embryonic stem cells
tissue (adult) stem cells

Question 9

Embryonic stem cells

Answer 9

early embryo

able to divide continuously

pluripotent - all genes can be expressed and can become all cells - important for growth

Question 10

Tissue adult stem cells

Answer 10

Found in mature organism

Function is to replenish all differentiated cells found in that specific tissue

multipotent - any type of cell of same tissue type

Question 11

Stem cells therapeutic uses

Answer 11

skin graft for burn victims

repair cornea - limbal cells

Question 12

Medical uses of stem cells

Answer 12

Treating patients with untreatable conditions

Growing organs for transplants

Medical research

Question 13

clinical issues with stem cells

Answer 13

no guarantee of success

difficult to find suitable stem cell donors

difficult to obtain patients embryonic stem cells

mutations have been observed

cultured stem cells can be contaminated by viruses

Question 14

Ethical issues with stem cell research

Answer 14

embryonic stem cell is unused embryos produced by in vitro fertilisation

for therapeutic cloning - is it right to create embryo for therapy and destroy them in process

could develop into person

at what stage is considered a person?

Question 15

Social issues with stem cell research?

Answer 15

Educating public

do benefits outweigh objections

patients could be exploited - paying a lot when stem cell research is only in early developmental stages

Question 16

Cancer

Answer 16

cells grow and divide my mitosis when it grows and divides uncontrollably due to not responding to regulatory signals this is cancer

Question 17

group of cancerous cells

Answer 17

tumour

Question 18

2 types of tumours

Answer 18

benign or malignant

Question 19

benign

Answer 19

grow slowly

usually grow within a membrane, so can easily be removed

do not invade other parts of body

Question 20

malignant

Answer 20

grow quickly

invade neighbouring tissues and can spread through bloodstream

As grows, cancel cells may fail to attach to each other spreading through body where may form secondary tumour. This process is called metastasis

Question 21

Metastasis

Answer 21

Secondary tumour

Question 22

Cancer cell are called

Answer 22

undifferentiated - do not carry out normal function

Question 23

what causes cancer?

Answer 23

Chemicals and other agents

genetic factors

lifesyle factors

Question 24

lifestyle factors that can cause cancer

Answer 24

viruses such as HPV, being spread though sexual intercourse

carcinogens in cigarettes

alcohol intake

ultraviolet radiation

diet, including fat and salt intake

Question 25

industrial and environmental factors at work that can lead to cancer?

Answer 25

exposure to ionising radiation

exposure to chemical carcinogens

Question 26

what cells can lose ability to continuously replicate themselves

Answer 26

differentiated cells