Stem cells and chromosomes and mitosis

Question 1

why do cells differentiate (change)?

Answer 1

to become specialised for their job

Question 2

what are adult stem cells?

Answer 2

• only in certain places in the body (bone marrow)
• can only produce certain types of specialised cell (e.g blood cells)

Question 3

how can stem cells possibly be able to cure many diseases?

Answer 3

• embyronic stem cells could be used to replace faulty cells in sick people
• therapeutic cloning, making an embryo that has the same genes as a patient
• this means that the stem cells from the embryo wouldn’t be rejected by the patient’s body

Question 4

why are some people against stem cell research?

Answer 4

• they feel embyros shouldn’t be used for research, as each one could be a human life
• they think scientists should be finding other resources of stem cells

Question 5

what can stem cells produce?

Answer 5

identical plants

Question 6

what are plant tissues called?

Answer 6

meristems, they are where growth occurs in the tips of roots and shoots

Question 7

what do the meristems contain?

Answer 7

stem cells that can differentiate into any type of plant cell

Question 8

what can clones (that stem cells make) be made of?

Answer 8

• rare species
• crop plants that have features that are useful for farmers

Question 9

what do chromosomes contain?

Answer 9

genetic information

Question 10

what are chromosomes?

Answer 10

• they are coiled up lengths of DNA molecules
• each one carries a large number of genes
• different genes control the development of different characteristics
• there are 23 pairs of chromosomes in a human cell

Question 11

what is the cell cycle?

Answer 11

• body cells in multicellular organisms divide to make new cells
• multicellular organisms use mitosis to grow and develop

Question 12

what are the two main stages of the cell cycle?

Answer 12

• growth and DNA replication
• mitosis

Question 13

what happens before a cell divides?

Answer 13

• the cell grows and increases the amount of subcellular structures
• the DNA is replicated and forms into X shaped chromosomes
• the left arm has the same DNA as the right arm of the chromosome

Question 14

what is mitosis?

Answer 14

the stage of the cell cycle when the cell divides

Question 15

what happens when the cell is ready for dividing?

Answer 15

• the chromosomes line up at the centre of the cell
• the two arms of each chromosome are pulled apart to opposite ends of the cell
• this divides the nucleus

Question 16

what happens after cell division?

Answer 16

• each set of chromosomes becomes the nucleus of a new cell
• the cytoplasm and cell membrane divide
• the cell has now produced two new cells, both containing the same DNA