division and differentiation

Question 1

What is differentiation?

Answer 1

Differentiation is when a cell develops more specialised functions by expressing the gene characteristics for that cell type.

Question 2

How does differentiation affect the gene in a cell?

Answer 2

Certain genes are switched off so the cell only expresses the required genes/proteins. Only the genes required for that particular cell type remain switched on.

Question 3

What is the result of differentiation?

Answer 3

Differentiation can result in a variety of cells specialised for different functions.

Question 4

Give 3 examples of specialised cells?

Answer 4

Sperm cell, muscle cell, nerve cell

Question 5

State somatic cell features?

Answer 5

• is anybody except those involved in reproduction.
  -they divide by mitosis to self renew and maintain the diploid chromosome number.
• they are differentiated/specialised
• they make up the body organs

Question 6

What are the germline cell features?

Answer 6

• are sex cells and the stem cells that form them.
• can divide by mitosis to make more germline cells (diploids)
• can divide by meiosis to form gametes which are haploids (egg or sperm)

Question 7

Where are stem cells found?

Answer 7

Developing embryos and some adult tissue for example bone marrow and liver.

Question 8

give an example of a pluripotent stem cell and a multipotent stem cell

Answer 8

pluripotent - embryonic stem cell
multipotent - adult tissue stem cell

Question 9

what are adult tissue stem cells involved in?

Answer 9

growth, repair and renewal.

Question 10

why does pluripotent have more potential than multipotent

Answer 10

pluripotent can be specialised/become any type of cell but multipotent is much more limited and can only become a specific cell type

Question 11

give some examples of therapeutic uses of stem cells

Answer 11

• damaged/diseased tissue and/or organs
• corneal replacement
• skin graft
• growing simple organs

Question 12

give some examples of how useful stem cells can be when used for research

Answer 12

• they can provide information on cell growth, differentiation and gene regulation.
• they can be used as model cells to investigate how diseases develop.
• can be used to test the safety and effectiveness of a drug.

Question 13

give some ethical considerations against the use of embryonic stem cells

Answer 13

• loss of potential life (would/could have developed into a human if not tampered with.)
• could this become a commercial industry? ~ treatment based on finances.
• eugenics/the ethical boundaries/used to change appearance of offspring.

Question 14

give some ethical considerations to use embryonic stem cells

Answer 14

• reduces the need to test new drugs on live volunteers ~ safer.
• additional healthy embryos from IVF can still serve a purpose.
• can vastly improves medical research and findings ~ human tissue specific.

Question 15

what is a cancer cell?

Answer 15

abnormal cells that divide excessively and don’t respond to regulatory signals. they avoid being destroyed by the immune system, resulting in a mass of abnormal cells called tumours.

Question 16

how does a secondary tumour form?

Answer 16

cancerous cells may fail to attach to one another and invade nearby blood vessels where they can spread to other places in the body and grow in a secondary tumor.