Biology Sac 1 Term 4

Question 1

What evidence shows reproduction in the fungi

Answer 1

The presence of the Zygospores

Question 2

What evidence shows the reproduction in the strawberry plant

Answer 2

The runners and the fruit

Question 3

Mitosis - prophase

Answer 3

Chromosomes condense and move to opposite cell ends

The nuclear membrane breaks down

Centrioles form spindle fibres

Question 4

Mitosis - metaphase

Answer 4

Centromeres continue to be drawn by the spindle fibres

Question 5

Metaphase - Anaphase

Answer 5

Spindle fibres contract, pulling the centromeres in different directions.

The centromere splits, separating the two chromatids.

The separated chromatids are then pulled to opposite ends

Question 6

Mitosis - telophase

Answer 6

Prophase in reverse
Nuclear membrane is formed around the chromosomes at each pole
The spindle fibres are dismantled and disappears

The chromosomes become longer and thinner

Question 7

G1 phase

Answer 7

Cell gains energy
Undergoes metabolic processes
Cell almost doubles in size
Cell gains multiple organelles

Question 8

S phase

Answer 8

Synthesis phase

Chromosomes are replicated in the nucleus

Question 9

G2 phase

Answer 9

Cell undergoes secondary growth

Cell prepares for mitosis by synthesising the materials such as proteins needed for division

Question 10

What is a centriole and how does it look during mitosis and what does it do during mitosis

Answer 10

A tiny cylinder structure found in eukaryotic cells

Composed of tubulin

The centrioles organise chromosomes and helps the formation of spindle fibres

Question 11

Haploid

Answer 11

23 (n)

Question 12

Diploid

Answer 12

46 (2n)

Question 13

Teraploid

Answer 13

48

Question 14

Fragmentation

Answer 14

When the body breaks down into multiple organisms

Question 15

Budding

Answer 15

Division of cytoplasm is unequal and the new individual arises as and outgrowth or bud

Question 16

Spores

Answer 16

A haploid cell that develop into a new organism without sexual reproduction

Question 17

Cloning - nuclear transfer

Answer 17

Removing nucleus of an unfertilised egg and replacing nucleus with nucleus of adult somatic cell
The egg is then transplanted back into organism

Question 18

Issues with cloning

Answer 18

• susceptible to disease ~ less genetic diversity
• high failure rate ~ current cloning technology is highly insufficient
• Adverse health effects ~ animal welfare concern medical problems occur throughout animals life
• premature ageing ~ telomeres of a clone is shorter
• cloning food products is a major concern

Question 19

Difference between mitosis in eukaryotes and prokaryotes

Answer 19

Eukaryotes have membrane bound organelles so the process of mitosis in prokaryotes is much simpler

Question 20

What are Mutagens

Answer 20

A physical, chemical or biological agent that caused a mutations in DNA such as cancer

Question 21

How does apoptosis occur in cells

Answer 21

The cells surface membrane buds to form apoptotic bodies
These contain the remnants of the cytoplasm, organelles and chromatin fragments. Phagocytic cells remove the apoptotic bodies.

Question 22

What happens if Apoptosis goes wrong?

Answer 22

Then webbing between fingers and toes remains

Question 23

What is pluripotent

Answer 23

A stem cell that can differentiate into any of the three germ layers

Question 24

What are the 3 germ layers?

Answer 24

Ectoderm (outermost layer) forms hair, epidermis, PNS, brain and spinal cord cells

Mesodermal (middle layer) forms muscles and cartilage and gonad cells and kidney cells

Endoderm (innermost layer) forms bladder, lungs and digestive system lining (pancreas, colon, liver and stomach