Human Cells Unit 1 KA 1

Question 1

What are Somatic cells?

Answer 1

Somatic cells are body cells that are not involved in reproduction

Question 2

How do Somatic cells divide?

Answer 2

Somatic cells divide by Mitosis to form more somatic cells

Question 3

How many chromosomes are in a Somatic cell?

Answer 3

There are 46 chromosomes in a Somatic cell, they are diploid

Question 4

Somatic cells differentiate to form different body tissue type - (4)

Answer 4

1) Epithelial
2) Connective tissue
3) Muscle tissue
4) Nervous tissue

Question 5

What does a Germaline cell do?

Answer 5

A Germaline cell produces Gametes

Question 6

Where are Germaline cells found?

Answer 6

Germaline cells are found in the ovaries (f) and testes (m)

Question 7

How do Germaline cells divide?
What do they form? (2)

Answer 7

1) Mitosis - more diploid germaline cells
2) Meiosis - haploid gametes

Question 8

What does division by Meiosis produce?

Answer 8

Division by Meiosis produces haploid gametes, reducing the number of chromosomes from 46 -> 23

Question 9

How many divisions are there in Meiosis?
How many haploid gametes does this produce?

Answer 9

There are two divisions in Meiosis, four haploid gametes are produced

Question 10

What is Cell Differentiation?

Answer 10

Cell differentiation is when an unspecialised cell becomes specialised to carry out a specific function

Question 11

How does a cell become Specialised?

Answer 11

A cell becomes specialised by expressing certain genes to produce proteins characteristic for that type of cell

Question 12

What are some examples of differentiated cells? (4)

Answer 12

1) Sperm cells
2) Goblet cells
3) Nerve cells
4) Red blood cells

Question 13

What are Stem cells?

Answer 13

Stem cells are cells that are unspecialised and have the ability to differentiate into specialised cells

Question 14

What are the two roles of Stem cells?

Answer 14

1) Self-renew (make copies of themselves)
2) Differentiate (make other types of cells)

Question 15

What are the two different types of Stem cells?

Answer 15

1) Tissue stem cells
2) Embryonic stem cells

Question 16

Which type of Stem cell is Multipotent?

Answer 16

Tissue stem cells are Multipotent - they can differentiate to produce a limited range of cell types

Question 17

Which type of Stem cell is Pluripotent?

Answer 17

Embryonic stem cells are Pluripotent - they can differentitate to make ALL cell types

Question 18

Where are Tissue stem cells found? (8)

Answer 18

1) Brain
2) Cornea
3) Testicles
4) Breast
5) Bone marrow
6) Intestines
7) Muscles
8) Skin

Question 19

Where are Embryonic stem cells found?

Answer 19

Embryonic stem cells are found in a human blastocyst

Question 20

Why do Tissue stem cells only differentiate to produce a limited range of cell types?

Answer 20

Tissue stem cells can only differentiate to produce a limited range of cell types because some of the genes in them have already been switched off

Question 21

Why can Embryonic stem cells differentiate to produce ALL cell types?

Answer 21

Embryonic stem cells can differentiate to produce ALL cell types because all the genes in them are still switched on

Question 22

What are Therapeutic uses of Stem cells? (2)

Answer 22

1) Corneal Repair
2) Regeneration of damaged skin

Question 23

What are the Research uses of Stem cells? (4)

Answer 23

Provides information on -
1) Cell growth
2) Differentiation
3) Gene regulation

Can be used as model cells to study how diseases develop and for drug testing

Question 24

What are Cancer cells?

Answer 24

Cancer cells are cells which divide excessively to produce a mass of abnormal cells called a tumour

Question 25

Why do **Cancer cells** divide excessively?

Answer 25

Cancer cells divide excessively because they do not respond to regulatory signals

Question 26

What happens if the cells within the tumour fails to attach?

Answer 26

If cells within the tumour fail to attack, they can spread through the body forming **secondary tumours**