Mitosis & Cell Cyle

Question 1

What is mitosis?

Answer 1

Mitosis is the process of cell division that results in two genetically identical daughter cells.

Question 2

True or False: Mitosis occurs only in prokaryotic cells.

Answer 2

False: Mitosis occurs in eukaryotic cells.

Question 3

What are the main stages of the cell cycle?

Answer 3

The main stages of the cell cycle are Interphase, Mitosis, and Cytokinesis.

Question 4

Fill in the blank: The phase where the cell grows and duplicates its DNA is called _____ .

Answer 4

Interphase

Question 5

What is the purpose of the G1 phase in the cell cycle?

Answer 5

The G1 phase is for cell growth and preparation for DNA replication.

Question 6

What happens during the S phase of the cell cycle?

Answer 6

During the S phase, DNA is replicated.

Question 7

Which phase follows the S phase?

Answer 7

The G2 phase.

Question 8

What occurs during prophase?

Answer 8

During prophase, chromosomes condense and become visible, the nuclear envelope breaks down, and spindle fibers begin to form.

Question 9

True or False: During metaphase, chromosomes align at the cell’s equatorial plane.

Answer 9

True.

Question 10

What is the function of spindle fibers?

Answer 10

Spindle fibers help separate chromosomes during mitosis.

Question 11

What key event occurs during anaphase?

Answer 11

Sister chromatids are pulled apart to opposite poles of the cell.

Question 12

During which phase does the nuclear envelope re-form?

Answer 12

During telophase.

Question 13

What is cytokinesis?

Answer 13

Cytokinesis is the division of the cytoplasm, resulting in two separate daughter cells.

Question 14

Fill in the blank: The checkpoint that ensures DNA is replicated correctly is the _____ checkpoint.

Answer 14

G2

Question 15

What role do cyclins play in the cell cycle?

Answer 15

Cyclins regulate the progression of the cell cycle by activating cyclin-dependent kinases (CDKs).

Question 16

What is the role of checkpoints in the cell cycle?

Answer 16

Checkpoints ensure that the cell is ready to proceed to the next phase and prevent errors.

Question 17

True or False: Apoptosis is a process that occurs during the cell cycle.

Answer 17

False: Apoptosis is programmed cell death, not a phase of the cell cycle.

Question 18

What is the difference between mitosis and meiosis?

Answer 18

Mitosis results in two identical daughter cells, while meiosis results in four genetically diverse gametes.

Question 19

What is a chromatid?

Answer 19

A chromatid is one of two identical halves of a replicated chromosome.

Question 20

During which phase do cells spend the majority of their time?

Answer 20

Cells spend the majority of their time in Interphase.

Question 21

What happens to the chromosome number during mitosis?

Answer 21

The chromosome number remains the same; it is duplicated and then equally divided.

Question 22

Fill in the blank: The phase of the cell cycle where the cell prepares for division is called _____ .

Answer 22

M phase

Question 23

What happens to the nucleolus during prophase?

Answer 23

The nucleolus disappears during prophase.

Question 24

What type of cells undergo mitosis?

Answer 24

Somatic cells undergo mitosis.

Question 25

What is the significance of the G0 phase?

Answer 25

The G0 phase is a resting state where cells are not actively preparing to divide.

Question 26

What is meant by 'sister chromatids'?

Answer 26

Sister chromatids are two identical copies of a single chromosome, connected at the centromere.

Question 27

True or False: Mitosis is a form of asexual reproduction.

Answer 27

True.

Question 28

What happens during the G2 phase?

Answer 28

During the G2 phase, the cell continues to grow and prepares for mitosis.

Question 29

Why is mitosis important in the life of an organism

Answer 29

Replaces old cells and how organisms grow and repair Increase in cell number

Question 31

2 events during interphase which prepare a cell for mitosis

Answer 31

DNA replication Cell elongation

Question 32

What happens during anaphase that results in the production of 2 genetically identical cells

Answer 32

Centromeres divide into 2 and pull the identical chromatids to opposite ends of the cell

Question 33

Describe the behaviour of chromosomes during mitosis and explain how this results in the production of 2 genetically identical cells

Answer 33

Thicken and shorten and become visible In metaphase the nuclear membrane disappears and the spindle fibres attach to chromosomes which are pulled to teh equator of the cell in a line One chromatid is pulled to each pole of the cell In telophase the nuclear envelope begins to reform around each new group of chromosomes

Question 34

How do drugs used to treat cancer disrupt the cell cycle

Answer 34

Preventing DNA from replicating Inhibiting the metaphase stage of mitosis by interferering with spindle formation

Question 35

How do u prepare the slide of a root tip

Answer 35

Squash technique - root tips are squashed gently and are stained Spreading the cells into a thin sheet and allowing individual cells undergoing mitosis to be clearly seen

Question 36

What is the method for the mitosis practical

Answer 36

Remove about 1 cm tip off of the root and place them in ethanoic alcohol To prevent mitosis from continuing in cells Place the root tips in warm 60c dilute hydrochloride acid to separate the cells Transfer the root tip to a microscope slide Using a pipettes add a suitable stain to stain chromosomes Place a coverslip on top of the root tip and press down firmly with a paper towel which spreads out cells so they are only one layer thick View the cells under a microscope

Question 37

Limitations of preparing the tissue

Answer 37

Squashing and staining the sample can generate artefacts But this can be decreased by more careful preparation of samples

Question 38

How do you calculate mitosis index

Answer 38

Number of cells in mitosis / total number of cells

Question 39

What should the student have done when counting cells to make sure that the mitotic index he obtained for this root tip was accurate

Answer 39

Repeat count to ensure figures are correct Large number of cells to ensure representative sample size

Question 40

One way in which a benign tumour differs from a malignant tumour

Answer 40

No metastasis , kept in one place

Question 41

Describe 2 ways in which both types of tumour may cause harm to the body

Answer 41

Benign - can harm singular organs Malignant - metastasis means it can spread to other organs quickly as it’s cancerous

Question 42

Why would the development of a mono polar mitotic spindle prevent mitosis

Answer 42

Not all chromatids can be pulled to the equator Anaphase prevented No separation of chromatids

Question 43

Why do you put the plant root in acid

Answer 43

To make the organelles / cell membranes permeable to the stain

Question 44

Describe how you would determine a reliable mitotic index from tissue observed with an optical microscope

Answer 44

Count cells in mitosis in field of view Divide the number of cells dividing by the total number of cells

Question 45

Why did other students calculate different mitotic indexes (2)

Answer 45

Are a different age so had different growing conditions Single field of view not representative of a root tip