Biology Unit 2 Sac 1

Question 1

Mitosis

Answer 1

The production of new cells that are genetically identical to the parent cell, an essential part of asexual reproduction

Question 2

Cytokinesis

Answer 2

The division of cytoplasm occurring after mitosis

Question 3

2 advantages and 1 disadvantage of asexual reproduction

Answer 3

Advantage - fast and rapid method of reproduction

Advantage - doesn’t require a mate

Disadvantage - the offspring are genetically identical meaning they are susceptible to the same illnesses and predators

Question 4

2 advantages and 1 disadvantage of sexual reproduction

Answer 4

Advantage - creates genetic diversity

Advantage - genetic mutations are more likely to be eliminated ( bred out ) in conjunction with natural selection

Disadvantage - requires finding a mate and therefore uses up much more time and energy

Question 5

M checkpoint

Answer 5

Is a checkpoint in metaphase, it checks if the sister chromatids are correctly attached to the microtubules of the spindle, to ensure the chromatids are pulled to either side of the cell

Question 6

Fragmentation

Answer 6

When an organism spontaneously divides into fragments, each fragment becomes a mature fully grown individual (e.g starfish loses a leg and regrow it)

Question 7

Budding

Answer 7

When a small part of the parent’s body separates from the rest and develops into a new individual ( e.g hydra and yeast )

Question 8

Spore formation

Answer 8

Spores are produced within a sac
Spores disperse
Plant into the ground to form new individual

Question 9

Binary fission (division of a prokaryote)

Answer 9

E,g bacteria cell, Division of nucleus followed by splitting of cell into two

2 daughter cells in 20 - 40 mins

Question 10

Mitosis and meiosis 3 similarities

Answer 10

Both are a form of cell division

Both occur in the nucleus of the cell

Both have spindle fibres separating chromosomes

Question 11

Mitosis and meiosis 3 differences

Answer 11

Mitosis occurs everywhere all the time meiosis occurs in the ovaries and testes

Mitosis produces somatic cells
Meiosis produces gametes

Mitosis produces genetically identical cells
Meiosis produces genetically varied cells

Question 12

Chaismata

Answer 12

The point at which crossing over and exchange of genetic material occurs between strands

Question 13

Mitosis and meiosis in plant vs animal cells

Answer 13

Animal cells undergo mitosis everywhere
Plant cells under go mitosis in specialised place = meristems

Animal have centrioles plants don’t

Question 14

Prophase

Answer 14

Prophase. Chromosomes gradually condense — becoming shorter and
thicker — and become visible as double-stranded structures (see gure 9.7).
e spindle forms and the nuclear membrane breaks down.

Question 15

Metaphase

Answer 15

The double-stranded chromosomes, also called dyads, line up
around the equator of the cell.

Question 16

Anaphase

Answer 16

The sister chromatids separate and are pulled to opposite ends of
the spindle by the contraction of spindle fibres

Question 17

Telophase

Answer 17

A nuclear membrane forms around each separate group of single-stranded chromosomes and the chromosomes gradually decondense.
Mitosis completes the division of the nucleus