B2

Question 1

Chromosomes

Answer 1

Contained in nucleus your genetic material in the form of chrmosomes. They are coiled up lengths of DNA molecules. Carry a large number of genes. Different genes mean different characteristics

Question 2

Chrmosomes in body

Answer 2

23 pairs. Humans have teo copies of each chromosomes

Question 3

Cell cycle

Answer 3

Body cells in multicellular organism divide to produce new cells. Results in two new cells identical to orginal cell, with same number of chromosomes

Question 4

Motiosis

Answer 4

The stage in cell cycle when cell divides. Multicellular organisms use mitosis to grow or replace cells that have been damaged

Question 5

DNA replication

Answer 5

Cell has to grow and increase amount of subcellular structures so theres one copy for each new cell. Once cell copied now ready for mitosis

Question 6

Process of mitosis

Answer 6

Chromosomes line up at the centre of the cell and cell fubres pull them apart. The two arms of each chromosome go to opposite ends of the cell. Membranes from around each of the sets of chromosomes becoming the nuclei of two new cells. Lastly cytoplasm and membrane divide. The cell now produced two new daughter cells containing exactly the same DNA

Question 7

Differation

Answer 7

Cell changes to become spcialised for job

Question 8

Animal cells differentiation

Answer 8

In early life

Question 9

Plant cell differentiation

Answer 9

Dont lose ability to be specialised

Question 10

How are differentiated cells used

Answer 10

Repairing and replacing cells

Question 11

Stem cells

Answer 11

Undifferentiated cells that can divide to produce lots more undifferentiated cells. They can differentiate into different types of cell depending on instruction given

Question 12

Where can stem cells be found

Answer 12

Early human embryos or adult bone marrow

Question 13

What do we do with stem cells

Answer 13

Can be grown in lab to produce clones and made to differentiate into specialised cells to use in medicine or research

Question 14

Stem cells in medicine

Answer 14

Stems cells from bone marrow of healthy person can replace faulty cells in patient who recieves them

Question 15

Embryonic stem cells

Answer 15

Also be used to replace faulty cells in sick people

Question 16

Risk of stem cells

Answer 16

Could be contaminated with a virus which could be passed on to the patient

Question 17

Why are some against stem cell research

Answer 17

Believe human embryos shouldnt be used for experiments since each one is a potentisl human life. Some argue the life of an existing patient is more important and argue that a lot of these embryos are unwanted and would be destroyed anyway

Question 18

Stem cells in plants

Answer 18

Found in meristems(parts of plant whee growth occurs) cam differentiate into any plant cell

Question 19

How can plant stem cells be used

Answer 19

Produce clones of plants quickly and cheaply, used to grow rare species,used to grow crops of identical plants