Extra SAC stuff

Question 1

Prokaryotes reproduce through binary fission.
In this process

Answer 1

a single chromosome is replicated.

Question 2

When compared to asexual reproduction in eukaryotic organisms, binary fission in prokaryotes

Answer 2

occurs at a faster rate.

Question 3

Programmed cell death will occur if a human cell

Answer 3

is no longer required by the body.

Question 4

Describe two differences between the chromosomes in prophase compared to the chromosomes in
telophase.

Answer 4

In prophase the chromosomes are condensed, making them visible, while in telophase the chromosome has
started to unwind and becomes less visible. (1 mark) In prophase a chromosome exists as two sister
chromosomes joined at the centromere. The chromosome has two molecules of DNA. In telophase the
chromosome has only one molecule of DNA.

Question 5

Describe the role played by phagocytes after the process of apoptosis.

Answer 5

The phagocytes engulf the apoptotic bodies that are produced when the cell is broken down. (1 mark)
The phagocytes then break down the apoptotic bodies. No inflammatory response results.

Question 6

Which one of the following is true of typical prokaryotic cell division?

Answer 6

There is an equal division of the cytoplasm.

Question 7

Evidence for the bacterial origin of chloroplasts is supported by observations that both chloroplasts and bacteria:

Answer 7

have a single circular chromosome.

Question 8

Molecules can move across a plasma membrane in various ways. Which of the following molecules are most likely to cross a
plasma membrane by passing between the phospholipid molecules within the membrane?

Answer 8

Carbon dioxide molecules

Question 9

cocci

Answer 9

= ball shape

Question 10

plant walls are usually made of

Answer 10

cellubse

Question 11

Rewrite the following list of steps in the correct order.

Answer 11

Binding of death ligand to FasR receptor.
Activation of caspase 3
Blebbing
Fragmentation of the nucleus.

Question 12

Name one characteristic observed in cells undergoing apoptosis (other than those outlined in the previous question).

Answer 12

Cell shrinkage

Question 13

When the trap is opening, by what process are potassium ions moved into the motor cells?

Answer 13

Active transport became ATP is required to move the potassium ions into the motor cell against their concentration gradient.

Question 14

When the trap is closing, by what process do potassium ions stream out of the cell?

Answer 14

facilitated diffusion, becuase the ions are moving down a concentration gradient and through a channel protein

Question 15

Explain why the cells lose their turgidity when potassium ions stream out of the motor cells.

Answer 15

As the potassium ions move out of the motor cells, water also moves out by osmosis since the ion outside the cell increases, and so turgor pressure is lost

Question 16

Although viruses are biologically important, they are not traditionally considered to be living things because they are not
composed of cells and are not able to reproduce independently of a host cell. List two other reasons why viruses are usually
considered non-living.

Answer 16

no metabolic process, no inputs/outputs, no growth, no response to stimuli

Question 17

The intrinsic pathway of programmed cell death

Answer 17

involves the release of cytochrome C from a mitochondrion.

Question 18

Programmed cell death results in the death of many cells. What major group of molecules help regulate this process?

Answer 18

Caspases regulate programmed cell death in both the intrinsic and extrinsic pathways.