Cell Division

Question 1

What is differentiation?

Answer 1

The process by which a cell changes to become specialised for its job

Question 2

Specialised features of a sperm cell?

Answer 2

• long tail
• streamlined head
• a lot of mitochondria
• enzymes to digest egg

Question 3

Specialised features of a nerve cell?

Answer 3

• long
• have branched connections

Question 4

Specialised features of a muscle cell?

Answer 4

• long
• contain lots of mitochondria

Question 5

Specialised features of a root hair cell?

Answer 5

• large surface area
• thin membrane

Question 6

What is a stem cell?

Answer 6

An undifferentiated cell

Question 7

Where are stem cells found?

Answer 7

Mainly in embryos

Question 8

How can stem cells cure different diseases?

Answer 8

• replace faulty cells
• can be made to contain the same genetic material as the patient

Question 9

What are the risks associated with stem cells?

Answer 9

contamination with viruses and genetic disease

Question 10

What are some people against stem cell research?

Answer 10

• Human embryos are a potential human life
• stem cells can carry disease

Question 10

How do some justify using human embryo stem cells?

Answer 10

• Embryos are usually unwanted ones
• they don’t technically exist yet and we should focus on those already suffering

Question 11

Where are plant stem cells found?

Answer 11

In the meristem

Question 12

What is good about plant stem cells?

Answer 12

• can produce quick and cheap plant clones
• are available the entire duration of a plants life
• can be edited to give the same crop more desirable qualities

Question 13

How many pairs of chromosomes does a human have

Answer 13

23

Question 14

What is mitosis?

Answer 14

The process of cell division

Question 15

Describe the process of mitosis? (6)

Answer 15

• cell grows and duplicates DNA and other subcellular structures
• nucleus breaks down
• chromosomes line up and are pulled to either side of the cell by spindle fibres
  -two nuclei form around each pair of chromosomes
• cytoplasm and cell membrane split to form two daughter cells

Question 16

Describe the process of binary fission?

Answer 16

• DNA replicates
• cell gets bigger and pairs of DNA move to either end of the cell
• cytoplasm divides and new cell walls start to form
• two identical daughter cells formed
• have variable numbers of plasmid copies

Question 17

How to keep a microorganism culture sterile?

Answer 17

• sterilise before use
• use an inoculating loop that had been passed through a hot flame
• lightly tape the lid on
• store the petri dish upside down to avoid condensation on the agar jelly

Question 18

How to investigate the effect of antibiotics on bacterial growth?

Answer 18

• place disks soaked in antibiotics on a plate with an even layer of bacteria
• ## add a control disk with no antibiotic