Producing new cells Flashcards

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1
Q

what is cell division used for?

A

Cell division produces new cells for growth and the repair of damaged tissues and the replacement of dead and damaged cells.

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2
Q

What is essential If new cells are required by an organism?

A

If new cells are required by an organism, the DNA/ chromosomes in the nucleus of a cell must be copied exactly (replicated) so that the new cells are able to grow and work properly.

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3
Q

Describe the process of mitosis.

A

Mitosis is the process by which a nucleus divides into two daughter nuclei, each of which receives exactly the same number of chromosomes as were present in the original nucleus. This is then followed by the division of the cytoplasm to produce two identical daughter cells.

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4
Q

What is the first stage of mitosis?

A

The nucleus containing long uncoiled chromosomes of which each doubles forming two identical chromatids.

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5
Q

What is the second stage of mitosis?

A

Short coiled-up chromosome forms.

made up of two chromatids

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6
Q

What is the third stage in mitosis?

A

Chromosomes get attached at the equator by spindle fibres and are held directly at the centromere.

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7
Q

What is the fourth stage of mitosis?

A

Pair of identical chromatids separate and move to opposite poles. (north pole and south pole).

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8
Q

What is the fifth stage of mitosis?

A

Separated chromatids are now called chromosomes. The cytoplams divides and the nuclear membrane forms

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9
Q

What is the final stage of mitosis?

A

Two identical daughter cells are formed each containing the same number of chromosomes as the original cell. The process can now be repeated.

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10
Q

What is chromosome complement?

A

The characteristic number of chromosomes in an organism’s cell is called its chromosome complement
(count the number of chromosomes present in a cell).

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11
Q

what does haploid mean?

A

A cell with one set of chromosomes is described as haploid.

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12
Q

What does diploid mean?

A

A cell with two sets of chromosomes is described as diploid.

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13
Q

Give two examples of sex cells.

A

sperm and egg cells are sex cells.

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14
Q

Why is a sex cell described as haploid?

A

A sex cell e.g. sperm or egg is described as haploid because it contains one SET of chromosomes.

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15
Q

How is a zygote formed?

A

When two sex cells fuse at fertilisation a zygote is formed.

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16
Q

Why is a zygote described as diploid?

A

Zygote has two SETS of chromosomes so is described as diploid.

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17
Q

Are cells produced from the zygote, by mitosis diploid or haploid?

A

All cells produced from a zygote are also diploid which means they contain two sets of chromosomes. The chromosomes in a zygote can be arranged in matching pairs.

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18
Q

What happens to the zygote after fertilisation?

A

After fertilisation the zygote continues to divide by mitosis.

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19
Q

What does the specialisation of cells lead to?

A

The specialisation of cells leads to the formation of a variety of cells, tissues and organs.

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20
Q

What are tissues?

A

Cells performing the same job link together as tissues.

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21
Q

What is an organ?

A

An organ is a structure composed of several different tissues coordinated to perform one or more functions. E.g. heart muscle tissue, blood vessel tissue and nerve tissue make up the organ called a heart.

22
Q

Name the stages of the hierarchy of organisation within a multicellular organism.

A
  1. Specialised cell- e.g muscle cell
  2. Tissue- muscle tissue
  3. Organ-heart
  4. System-circulatory system
  5. Organism-circulatory system makes up part of the human body.
23
Q

What is a multicellular organism made up of?

A

A multicellular organism is made up of several systems working together for survival of the organism.

24
Q

What are the two cell types in blood tissue?

A

Red blood cell and white blood cell.

25
Q

What are the specialised structural features of a red blood cell?

A

small size and biconcave shape present a relatively large surface area; rich supply of haemoglobin present.

26
Q

What is the function of red blood cells?

A

Uptake and transport of oxygen to living cells.

27
Q

What are the specialised structural features of a white blood cell?

A

Able to change shape; sacs of microbe-digesting enzymes present in some types.

28
Q

What is the function of white blood cells?

A

Destruction of invading microbes.

29
Q

What is the cell type of the nerve tissue called?

A

Motor neuron.

30
Q

What are the specialised structural features of a motor neuron cell?

A

Axon (long insulated extension of the cytoplasm).

31
Q

What is the function of the motor neuron cell?

A

Transmission of nerve impulses.

32
Q

What are the specialised structural features and functions of a sperm cell?

A

Has a tail to help to help it swim through the female reproductive system to the egg.

33
Q

What are the cell types of the tissue mesophyll?

A

Palisade mesophyll and spongy mesophyll.

34
Q

What are the specialised structural features in a palisade mesophyll?

A

Chloroplasts present; columnar shape (allows densely packed green layer to be presented to light).

35
Q

What is the function of the palisade mesophyll cell?

A

Primary region of light absorption and photosynthesis.

36
Q

What are the specialised structural features in a spongy mesophyll cell?

A

“round” shape allows loose arrangement in contact with the moist air spaces for absorption of carbon dioxide.

37
Q

What is the cell type of Xylem tissue called?

A

Vessel cell.

38
Q

What are the specialised structural features of a vessel cell?

A

Hollow tube; wall strengthened by lignin; lignin deposited as rings or spirals allowing expansion and contraction.

39
Q

What is the function of the vessel cell?

A

Support and water transport up the plant.

40
Q

What are the cell types of phloem tissue?

A

Sieve tube and companion cell

41
Q

What are the specialised structural features of sieve tube cells?

A

Sieve plates and continuous stream of cytoplasmic strands (but no nucleus).

42
Q

What is the function of a sieve tube?

A

Transport of soluble carbohydrates up and down the plant.

43
Q

What are the specialised structural features of a companion cell?

A

Large nucleus in relation to cell size.

44
Q

What is the function of a companion cell?

A

Control of sieve tube functions.

45
Q

What are stem cells?

A

Stem cells are unspecialised animal cells involved in tissue growth and repair.

46
Q

What are the functions of stem cells?

A

They can divide (by mitosis) in order to self-renew, (and remain unspecialised).

Have the potential to become different types of cells when required e.g. to replace cells that have died, become damaged or lost.

47
Q

Name two types of stem cells.

A

Embryonic stem cells and tissue stem cells.

48
Q

Where do embryonic stem cells come from?

A

embryonic stem cells can be obtained from the embryo at a very early stage.

49
Q

Where do tissue stem cells come from?

A

Tissue stem cells can be found in the body throughout life.

50
Q

What type of cells do embryonic stem cells have the potential to become?

A

These cells have the potential to become any type of cells found in the body. For example, an embryonic stem cell could have become a nerve cell, skin cell, bone cell, etc.

51
Q

What type of cells do tissue stem cells have the potential to become?

A

These cells have the potential to become only a few types of cells. For example, adult stem cells in bone marrow (inside your thigh bone) can only become types of white blood cells, red blood cells but no other type of cell.