Revision Worksheet Notes

Question 1

What is binary fission

Answer 1

Involves division of the parent body in two, fairly equal, parts to produce two identical cells. It is a form of asexual reproduction.

Question 2

Explain why the formation of the cross wall is important in binary fission.

Answer 2

It separates the parent and daughter cell into two identical cells.

Question 3

Explain the term generation time

Answer 3

The time it takes for a population of bacteria to double in number,

Question 4

Outline what occurs in interphase?

Answer 4

The cell grows,
carries out its normal activities,
replicates its DNA,
prepares for cell division.

Question 5

Outline what occurs in mitosis

Answer 5

The nucleus of the cell divides in two

Question 6

Outline what occurs in cytokinesis

Answer 6

Cytoplasm divides and two new daughter cells are produced.

Question 7

What is the purpose of mitosis?

Answer 7

To ensure that the two daughter cells inherit an equal and identical complement of chromosomes.

Question 8

What must occur before mitosis takes place?

Answer 8

Interphase

Question 9

What is the purpose of the spindle fibers?

Answer 9

To equally divide the chromosomes

Question 10

Where do spindle fibers originate?

Answer 10

Centrosomes

Question 11

Summarize what happens in prophase.

Answer 11

• Chromosome condenses
• Nucleolus disappears
• Nuclear envelope breaks down
• Chromosomes are released

Question 12

Summarize what happens in metaphase.

Answer 12

• Chromosomes continue to be condensed
• Nucleus disappears
• Chromosomes align in the center of the dividing cell

Question 13

Summarize what happens in anaphase?

Answer 13

• Sister chromatids separate from each other
• Chromatids are pulled to opposite ends of the cell

Question 14

What happens during telophase?

Answer 14

• Chromosomes begin to uncoil
• Nuclear membrane forms around each set of chromosomes

Question 15

What is the purpose of cytokinesis?

Answer 15

To physically separate a mother cell into two daughter cell

Question 16

Describe the differences between cytokinesis in an animal and a plant cell

Answer 16

In plants, a cell wall forms in between the daughter cells. In animals, cleavage furrow forms which pinches the cell in half.

Question 17

What is the mitotic index

Answer 17

Number of cells in mitosis/total number of cells

Question 18

Briefly describe what happens in each of the following phrases: G1

Answer 18

Cells accomplish most of their growth. They get bigger in size, and make proteins and organelles.

Question 19

Briefly describe what happens in each of the following phrases: G2

Answer 19

The cell grows more, makes proteins and organelles, prepares for mitosis

Question 20

Briefly, what happens in the M phase?

Answer 20

Nuclear division, cytoplasmic division

Question 21

Briefly, what happens in the S phase?

Answer 21

The cell synthesizes a complete copy of the DNA in its nucleus

Question 22

What are the three reasons cells divide?

Answer 22

For the survival and growth of organisms

Maintaining chromosome numbers

Damaged cells are renewed