Human Cells Unit 1 KA 1 Flashcards
Division and Differentiation
What are Somatic cells?
Somatic cells are body cells that are not involved in reproduction
How do Somatic cells divide?
Somatic cells divide by Mitosis to form more somatic cells
How many chromosomes are in a Somatic cell?
There are 46 chromosomes in a Somatic cell, they are diploid
Somatic cells differentiate to form different body tissue type - (4)
1) Epithelial
2) Connective tissue
3) Muscle tissue
4) Nervous tissue
What does a Germaline cell do?
A Germaline cell produces Gametes
Where are Germaline cells found?
Germaline cells are found in the ovaries (f) and testes (m)
How do Germaline cells divide?
What do they form? (2)
1) Mitosis - more diploid germaline cells
2) Meiosis - haploid gametes
What does division by Meiosis produce?
Division by Meiosis produces haploid gametes, reducing the number of chromosomes from 46 -> 23
How many divisions are there in Meiosis?
How many haploid gametes does this produce?
There are two divisions in Meiosis, four haploid gametes are produced
What is Cell Differentiation?
Cell differentiation is when an unspecialised cell becomes specialised to carry out a specific function
How does a cell become Specialised?
A cell becomes specialised by expressing certain genes to produce proteins characteristic for that type of cell
What are some examples of differentiated cells? (4)
1) Sperm cells
2) Goblet cells
3) Nerve cells
4) Red blood cells
What are Stem cells?
Stem cells are cells that are unspecialised and have the ability to differentiate into specialised cells
What are the two roles of Stem cells?
1) Self-renew (make copies of themselves)
2) Differentiate (make other types of cells)
What are the two different types of Stem cells?
1) Tissue stem cells
2) Embryonic stem cells
Which type of Stem cell is Multipotent?
Tissue stem cells are Multipotent - they can differentiate to produce a limited range of cell types
Which type of Stem cell is Pluripotent?
Embryonic stem cells are Pluripotent - they can differentitate to make ALL cell types
Where are Tissue stem cells found? (8)
1) Brain
2) Cornea
3) Testicles
4) Breast
5) Bone marrow
6) Intestines
7) Muscles
8) Skin
Where are Embryonic stem cells found?
Embryonic stem cells are found in a human blastocyst
Why do Tissue stem cells only differentiate to produce a limited range of cell types?
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
Why can Embryonic stem cells differentiate to produce ALL cell types?
Embryonic stem cells can differentiate to produce ALL cell types because all the genes in them are still switched on
What are Therapeutic uses of Stem cells? (2)
1) Corneal Repair
2) Regeneration of damaged skin
What are the Research uses of Stem cells? (4)
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
What are Cancer cells?
Cancer cells are cells which divide excessively to produce a mass of abnormal cells called a tumour
Why do Cancer cells divide excessively?
Cancer cells divide excessively because they do not respond to regulatory signals
What happens if the cells within the tumour fails to attach?
If cells within the tumour fail to attack, they can spread through the body forming secondary tumours
