Specialised Cells Flashcards

1
Q

What is differentiation

A

Genes (such as DNA) inside the nucleus are switched on and off causing the cell to make different proteins. This leads to different structures being formed.

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2
Q

What is a specialised cell.

A

A cell that is adapted to perform a certain function

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3
Q

What is the function of a sperm cell.

A

To carry the fathers genes and fertilise an egg to make a baby.

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4
Q

What adaptations do a sperm cell have to help it carry out its function.

A
  1. Tail is long and it rotates to propel the cell to search for the egg.
  2. Lots of mitochondria to provide energy for a long distance swim.
  3. Head contains nucleus with half the fathers DNA (chromosomes) so the baby is healthy.
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5
Q

What is the function of a nerve cell?

A

To conduct electrical pulses to communicate with other cells muscles or glands.

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6
Q

What adaptations help a nerve cell to carry out its functions

A

Elongated axon to reach and transmit impulses directly between cells that are far apart.
Myelin sheath insulates the axon to speed up impulse transmission.
Lot’s of dendrites to receive impulses from other cells

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7
Q

What is the function of a muscle cell

A

To contract and move.

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8
Q

Adaptations that help a muscle cell to carry out its function?

A

Lot’s of mitochondria to release energy from respiration for contraction.
Lot’s of ribosomes to make protien filaments to slide over each other for contraction.
More than one nucleus per cell to make sure contraction is in unison.

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9
Q

What is the function of a root hair cell

A

To absorb water and minerals from the soil

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10
Q

Adaptations that help a root hair cell carry out it’s function.

A

Large surface area for molecules to move into the plant at a faster rate.
No chloroplast as it is underground and so there is more room for other structures.
Large vacuole to maintain shape and remove water from cytoplasm to maintain a concentration gradient for osmosis

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11
Q

What is the function of a xylem cell.

A

To carry and transport water minerals from the soil and leaves.

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12
Q

Adaptations that help xylem carry out there function

A

Living when formed but then die and lose contents to create hollow tubes to allow water to flow uninterrupted.
A special chemical called lignin builds up cell wall to make it extra strong to withstand water pressure.

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13
Q

What is the function of phloem

A

To carry sugars made in leaves up and down plant to other areas

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14
Q

Adaptations that help phloem complete there function.

A

Cell wall between cells break down to form sieve plates for movement of dissolved sugars.
Most internal structures are lost but cell is still alive. They are kept alive by companion cells which have lots of mitochondria that provides energy to move sugars up and down

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15
Q

What is stage one of the cell cycle.

A

Growth and replication of sub cellular structures

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16
Q

What is stage 2 of the cell cycle

A

Mitosis (nuclear division)

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17
Q

What is stage 3 of the cell cycle

A

Cytoplasm and cell membrane split in two forming two new daughter cells.

18
Q

What are the two daughter cells.

A

They are identical to the one the were formed from

19
Q

What are chromosomes

A

Chromosomes are long threads of DNA wrapped around proteins found inside the nucleus.

20
Q

How many chromosomes are there in a cell.

A
  1. 23 from father, 23 from mother. All the chromosomes are arranged in pairs.
21
Q

What is a haploid

A

A cell with half the number of chromosomes as a normal cell

22
Q

What is a diploid.

A

A cell with the full 46 chromosomes.

23
Q

What happens in stage one of the cell cycle

A

All the chromosomes duplicate them selfs. The appear as x shapes. Also other sub cellular structures duplicate

24
Q

What happens in mitosis (stage two of the cell cycle)

A

During the mitosis the nucleus disappears and the chromosomes are seen as wiggly lines in the middle of the cell. Then each x is pulled apart and the chromosomes move to the opposite part of the cell

25
Q

What happens in stage 3 of the cell cycle.

A

The cells divide into two daughter cells. This is called cleavage.

26
Q

How do you calculate the length of a cell cycle.

A

Number of cells in each stage divided by total number of cells times total length of one cell cycle.

27
Q

What is a zygote

A

A fertilised egg cell

28
Q

What is a stem cell

A

A cell that can differentiate into any type of specialised cell

29
Q

What can plant cells do throughout life

A

They retain the ability to differentiate so we can take cuttings of a plant and regrow the plant.

30
Q

What are the two types of stem cells in animals

A

Embryonic stem cells and adult stem cells.

31
Q

What are embryonic stem cells

A

They are stem cells from the very early embryo that can differentiate into any type of cell

32
Q

What are adult stem cells

A

Limited numbers of cells that are found in different regions of the body but can only differentiate into related cell types
E.G if they are from blood cells they can only turn into blood or blood related cells.

33
Q

What are some advantages of embryonic stem cells

A

Plentiful supply (one embryo contains a lot of cells).
Can make all cell types.
Can treat lots of diseases
Painless for embryo and person being treated.

34
Q

Disadvantages of embryonic stem cells

A

Kills the embryo.
Unreliable
Don’t know what the long term effects are
Embryo can’t give consent.

35
Q

Advantages of using adult stem cells

A

No ethical/consent issues
Safe and well tested
Quick recovery for donor and patient

36
Q

Disadvantages for adult stem cells

A

Risk of infection
Only for limited cell types
Painful to harvest for donor

37
Q

What is therapeutic cloning.

A

It is the transfer of one nucleus into a stem cell from the patient so that it has the same genetics as the patient. This can them be used to treat any disease.

38
Q

Advantages of therapeutic cloning

A

Stem cells identical to patient
Can create all cell types
Huge benefits for medicine
Reduces waiting time for organ transplants

39
Q

Ethical issues with therapeutic cloning.

A

Embryos artificially created and the destroyed
A potential life is being killed
Already a shortage of egg donors for IVF so should use be diverted from infertile couples
Poor success rate in this technology

40
Q

What is the general term for an animal or plant cell?

A

Eukaryotic cells

41
Q

What kind of cell makes up a single celled organism (e.g) bacteria).

A

Prokaryotic cells.