8.2.1 Most cells DNA not translated Flashcards

1
Q

what is the process by which cells develop into a specialised structure suited to the role they are carrying out

A

cell differentiation

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2
Q

what is differentiation

A

is the process by which stem cells become specialised.

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3
Q

what is a stem cell

A

is an undifferentiated cell that can divide by mitosis an unlimited number of times and turn into other specific cell types

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4
Q

what can stem cells do

A

after dividing can remain as stem cell of divide into specialised cells - differentiation

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5
Q

what is the name for the process by which stem cells can differntatied into more speculated cells

A

potency

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6
Q

name the 3 types of potency

A

Totipotency
Pluripotency
Multipotency

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7
Q

what is a totipotent cell?

A

can divide and produce any type of body cell

embryonic stem cells

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8
Q

How do totipotent cells become specialised

A

They translate only part of their DNA which results in cell specialisation

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9
Q

where are totipotent cells found

A

early mammilian embryo - occur for limited time there

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10
Q

why are there no totipotent cells present in the later stages of development

A

as cells lose their ability to differentiate into any cell type

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11
Q

name and define the three types of stem cells

A

Totipotent – Can develop into any cell type, including the placenta and embryo.

Pluripotent – Can develop into any cell type excluding the placenta and embryo.

Multipotent – Can only develop into a few different types of cells.

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12
Q

what are pluripotent cells

A

stem cells that are found in embryos and can become any type of cell

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13
Q

what are pluripotent cells used in

A

research
treat Hyman disorders
used to regrow damaged cells e.g. burnt skin cells

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14
Q

what are the issues with this treatment

A

doesn’t work

Stem cells continue to divide to create tumours

ethic issues - moral to make therapeutic clone to make embryos
- using embryos that are destroyed later

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15
Q

what are multipotent and unipotent stem cells?

A

found in mature mammals and can divide to form a limited number of different cell types

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16
Q

what are examples of multipoint cells

A

bone marrow cells

17
Q

difference between multipoint and unipotent cells

A

multi - can differentiate into a limited number of cells, whereas
unipotent cells can only differentiate into one type of cell.

18
Q

What happens to totipotent cells during embryonic development?

A

Certain parts of the DNA are selectively translated so that only some genes are ‘switched on’ in order to differentiate the cell into a specific type and form the tissues that make up the foetus.

19
Q

Give a unique feature of pluripotent cells and the use of this feature.

A

They can divide in unlimited numbers and can therefore be used to repair or replace damaged tissue.

20
Q

What is a unipotent cell? Give an example.

A

A cell that can only develop into one type of cell. This happens at the end of specialisation when the cell can only propagate its own type. An example is cardiomyocytes (heart cells).

21
Q

Which types of stem cells are found in embryos?

A

Totipotent and pluripotent.
Multipotent and unipotent cells are only found in mature mammals.

22
Q

Give some uses of stem cells.

A

Medical therapies (e.g. bone marrow transplants, treating blood disorders).
Drug testing on artificially grown tissues.
Research (e.g. on the formation of organs and embryos

23
Q

How are induced pluripotent stem cells produced?

A

From mature, fully specialised (somatic) cells. The cell regains capacity to differentiate through the use of proteins, in particular transcription factors.

24
Q

How can stem cells be used in the treatment of human disorders

A
  • transplanted into patients to divide in unlimited numbers
  • then differentiate into required healthy cells (to replace damaged cell)
25
Q

How are induced pluripotent stem (iPS) cells produced

A
  1. Obtain adult somatic body cells from patient
  2. Add specific protein transcription factors associated with pluripotency to cells so they express genes associated with pluripotency
    Transciption factors attatch to promoter regions of DNA, stimulating or inhibiting transcription
  3. Culture cells to divide by mitosis

Once made iPS cells can divide and differentiate into healthy cells to be transplated into the same patient

26
Q

Positives of using stem cells in treating human disorders

A
  • can divide and differentiate into required healthy cells - save lives
  • embryos are often left over from IVF so would otherwise be destroyed
  • iPS cells unlikely to be rejected by patients immune system as they are their own cells
  • iPS cells can be made without destruction of embryo and adult can give permission
27
Q

Negatives of using stem cells in treating human disorders

A
  • ethical issues with embryonic stem cells (destruction of a potential life)
  • immune system could reject cells and immunosupressant drugs are required
  • cells could divide uncontrollably leading to cancer
28
Q

How are induced pluripotent stem cells made?

A

-Produced from adult somatic cells
- appropriate protein transcription factors are used to switch on the genes that were swtiched off to make the cell specialized

29
Q

How do IPS cells overcome ethical issues of using embryonicnstem cells

A

They dont cause destruction of an embryo and the sdult can give permission

30
Q

How can pluripotent cells treat human disorders

A
  • they can replaaced damaged cells as they divide in unlimited numbers