Cell Division

Question 1

What is cancer?

Answer 1

Uncontrollable cell division

Cancer is characterized by mutations in genes that control cell division.

Question 2

What causes mutations in DNA?

Answer 2

Mutagens such as ionizing radiation or carcinogenic chemicals

Examples include UV rays and substances found in cigarette smoke.

Question 3

What is the role of apoptosis in cancer?

Answer 3

Cancer cells may die through apoptosis or be destroyed by the immune system

Apoptosis is a process of programmed cell death.

Question 4

What happens if cancer cells pass the checkpoints in the cell cycle?

Answer 4

They continue to divide by mitosis

This can lead to the formation of tumors.

Question 5

What are the two types of tumors?

Answer 5

• Malignant
• Benign

Malignant tumors invade other tissues and can spread (metastasis), while benign tumors grow slowly and do not invade.

Question 6

Describe a malignant tumor.

Answer 6

Grows quickly, invades tissues, can spread to other organs

Malignant tumors are more likely to be life-threatening.

Question 7

Describe a benign tumor.

Answer 7

Grows slowly, kept in one place, does not invade tissues

Benign tumors are usually not life-threatening.

Question 8

What is the effect of cancer treatments on cell division?

Answer 8

They target the cell cycle to stop division

Treatments can kill tumor cells but may also affect normal rapidly dividing cells.

Question 9

What is chemotherapy?

Answer 9

Prevents the synthesis of enzymes required for DNA replication

This stops the cell cycle before the S phase.

Question 10

What is the role of radiotherapy in cancer treatment?

Answer 10

Damages DNA to force cells into apoptosis

If DNA is damaged, the cell will not pass checkpoints and will kill itself.

Question 11

What is the effect of drugs that prevent spindle fibers from forming?

Answer 11

Prevents mitosis, leading to cells with unequal DNA

This stops cells from functioning or dividing.

Question 12

What are oncogenes?

Answer 12

Code for proteins that regulate the transition between cell stages

Oncogenes play a role in promoting cell division.

Question 13

What are tumor suppressor genes?

Answer 13

Produce proteins that stop the cell cycle

They help regulate cell division and prevent cancer.

Question 14

What affects the rate of cell division?

Answer 14

Nutrients, oxygen, hormones (growth factors), and genes

Environmental factors play a significant role.

Question 15

What happens if genes controlling cell division are mutated?

Answer 15

Cells may grow out of control

This can lead to cancer.

Question 16

What could happen if damaged cells survive after genetic mutation?

Answer 16

They can continue to divide uncontrollably

This exacerbates the risk of tumor formation.

Question 17

How does vincristine lead to cancer treatment?

Answer 17

Prevents spindle fibers from forming, disrupting mitosis

This leads to cell death or malfunction.

Question 18

What are the two strands of a chromosome called?

Answer 18

Sister chromatids

Sister chromatids are identical copies of a chromosome, joined at the centromere.

Question 19

When are chromosomes visible?

Answer 19

During cell division

Chromosomes are formed during interphase when DNA replicated however are only visible during prophase of mitosis when they condense

Question 20

What is the function of the centromere?

Answer 20

Joins sister chromatids

The centromere is the region where sister chromatids are joined.

Question 21

What is the acronym used to remember the stages of mitosis?

Answer 21

I.P.M.A.T

The stages are Interphase, Prophase, Metaphase, Anaphase, and Telophase.

Question 22

What happens to DNA during interphase?

Answer 22

It is uncondensed

The chromosomes are not visible during interphase.

Question 23

What occurs during prophase?

Answer 23

Chromosomes condense and become visible , centrioles move to opposite poles of the cell and start to produce spindle fibres

The nucleolus disappears and the nuclear envelope begins to break down.

Question 24

What is the role of centrioles during prophase?

Answer 24

Produce spindle fibres

Centrioles move to the poles of the cell and start extending spindle fibres.

Question 25

What characterizes metaphase?

Answer 25

Chromosomes align at the equator ## Footnote Spindle fibres are attached to the centromeres of chromosomes.

Question 26

What happens during anaphase?

Answer 26

Sister chromatids are pulled to opposite poles ## Footnote The centromere splits, allowing chromatids to move apart.

Question 27

What occurs in telophase?

Answer 27

Nuclear envelopes reform ## Footnote Chromosomes begin to uncoil, and the cytoplasm divides, forming two daughter cells.

Question 28

How does the amount of DNA in daughter cells compare to the cell in interphase?

Answer 28

Each new cell has half the amount of DNA ## Footnote This amount is restored when interphase begins and DNA is replicated again.

Question 29

What factors can influence the time taken for cells to go through mitosis?

Answer 29

Type of cell and conditions during division ## Footnote Conditions such as temperature and nutrient availability can affect mitosis duration.

Question 30

Fill in the blank: The _______ disappears during prophase.

Answer 30

Nucleolus ## Footnote The nucleolus is a structure within the nucleus that disappears as mitosis begins.

Question 31

True or False: The spindle fibres are produced during telophase.

Answer 31

False ## Footnote Spindle fibres are produced during prophase, not telophase.

Question 32

What shape do chromatids take during anaphase?

Answer 32

V-shape ## Footnote The V-shape indicates that the chromatids are being pulled apart.

Question 33

What are the two types of cell division in eukaryotic cells?

Answer 33

Mitosis and Meiosis ## Footnote Mitosis produces genetically identical diploid daughter cells, while meiosis produces genetically non-identical haploid daughter cells.

Question 34

What is the primary purpose of mitosis?

Answer 34

Growth of tissues, replacement of lost cells, repairing damaged tissue, formation of clones of white blood cells, and cancerous tumor formation ## Footnote Mitosis is also a form of asexual reproduction.

Question 35

What is the primary purpose of meiosis?

Answer 35

Production of haploid sex cells for sexual reproduction

Question 36

What is interphase?

Answer 36

The process cells that can divide go through before division ## Footnote It starts with a cell produced by mitosis and ends when the cell is ready to divide again.

Question 37

What are the three stages of interphase?

Answer 37

* G1 (gap 1) phase * S (synthesis) phase * G2 (gap 2) phase

Question 38

What occurs during the G1 phase of interphase?

Answer 38

The cell elongates and new organelles and proteins are made

Question 39

What occurs during the S phase of interphase?

Answer 39

The cell replicates its DNA

Question 40

What occurs during the G2 phase of interphase?

Answer 40

The cell continues to elongate and proteins needed for cell division are made

Question 41

What is cytokinesis?

Answer 41

The final stage where the cytoplasm divides and two genetically identical cells are formed

Question 42

True or False: Specialized cells and stem cells can move from G1 into a resting phase called GO.

Answer 42

True

Question 43

How does the amount of DNA change during interphase?

Answer 43

It doubles as the DNA is replicated

Question 44

Fill in the blank: Mitosis produces _____ genetically identical diploid daughter cells.

Answer 44

2

Question 45

Fill in the blank: Meiosis produces _____ genetically non-identical haploid daughter cells.

Answer 45

4

Question 46

What happens to organelles during interphase?

Answer 46

They are replicated so there will be enough for both new cells

Question 47

What is the significance of ATP production during interphase?

Answer 47

Increased ATP production provides energy required for cell division

Question 48

What is the process by which bacteria reproduce?

Answer 48

Binary fission ## Footnote Binary fission is a form of asexual reproduction in bacteria.

Question 49

How does binary fission compare to mitosis?

Answer 49

Very similar ## Footnote Binary fission is analogous to mitosis but occurs in prokaryotic cells.

Question 50

What type of DNA do prokaryotic cells have?

Answer 50

Single loop of circular DNA ## Footnote Prokaryotic DNA is not linear and does not condense into chromosomes.

Question 51

What happens to the DNA at the start of binary fission?

Answer 51

It is replicated ## Footnote Along with any plasmids during the initial phase of binary fission.

Question 52

What increases in number during binary fission?

Answer 52

Ribosomes ## Footnote The number of ribosomes increases to support protein synthesis.

Question 53

What occurs after DNA replication in binary fission?

Answer 53

The cell elongates ## Footnote Elongation prepares the cell for division.

Question 54

What is similar to cytokinesis in plant cells during binary fission?

Answer 54

Cytoplasm divides ## Footnote The cytoplasm splits, and the cell wall reforms at the center.

Question 55

What is the product of binary fission?

Answer 55

Two new cells ## Footnote Each cell has a single, identical copy of the circular DNA loop.

Question 56

At what intervals do bacteria typically divide?

Answer 56

Every 20 minutes ## Footnote Division occurs as long as there are sufficient resources.

Question 57

What mathematical calculation can be made regarding bacterial growth?

Answer 57

Number of bacteria = initial number x 2^n ## Footnote 'n' represents the number of intervals.

Question 58

True or False: Bacteria can reproduce through sexual reproduction.

Answer 58

False ## Footnote Bacteria reproduce asexually through binary fission.