Cell Division Chapter 6

Question 1

What are the stages in cell division

Answer 1

Cytokinesis
Karyokinesis

Question 2

What are the function of cytokinesis and karyokinesis?

Answer 2

Karyo: Division of Nucleus
Cyto: Division of cytoplasm

Question 3

What are the organism’s body cell divided into?

Answer 3

Somatic cells and gametes

Question 4

What are gametes?

Answer 4

• Reproductive cells
• Produced through Meiosis
• Contains a haploid number of chromosomes ( 23 ) , that is each cell contains one set of chromosomes

Question 5

What are somatic cells?

Answer 5

• Body cells apart from gametes
• Produced through mitosis
• Contains a diploid number of chromosomes, that is each cell contains two set of chromosomes

Question 6

What are the pair of parental and maternal chromosomes present in cells called?

Answer 6

Homologous chromosomes

Question 7

What are the chromosomes from the male parent called?

Answer 7

Paternal chromosomes

Question 8

What are chromosomes from the female parent called?

Answer 8

Maternal Chromosomes

Question 9

What does the cell cycle consist of?

Answer 9

Interphase and M phase

Question 9

What is the cell cycle?

Answer 9

Sequence of events that involve DNA multiplication and cell division to produce 2 daughter cells

Question 10

Which of the phases in cell cycle is the longest?

Answer 10

Interphase

Question 11

What is the interphase made up of?

Answer 11

G1, G2 and S

Question 12

What is the M phase made up of?

Answer 12

Mitosis and Cytokinesis

Question 13

What is the function of the G1 phase during cell cycle

Answer 13

• Cell grows
• Cell components ( Mitochondrion ) are produced at this stage
• Proteins are synthesised during this time
• At this stage, nucleus looks big and chromosome is the form of chromatin

Question 14

What is the function of the S phase during the cell cycle?

Answer 14

• DNA synthesis occurs
• DNA in the nucleus is replicated
• Each chromosomes multiplies into 2 identical chromosomes known as sister chromatids and are joined at the centromere

Question 15

What is the function of the G2 phase during cell cycle?

Answer 15

• Cells continue to grow and remain active metabolically
• Cells gather energy and make final arrangements to enter the next stage of cell division
• After this, cell enters M phase

Question 16

What is mitosis

Answer 16

Division of the nucleus of the parent cell into 2 nuclei.

Question 17

What phases are in mitosis?

Answer 17

Prophase
Metaphase
Anaphase
Telophase

Question 18

What goes on during the prophase of the mitosis?

Answer 18

• Chromatin shortens and thicken to form a chromosome structure
• Each chromosome is made up of 2 identical threads known as sister chromatids
• Nucleus membrane disintegrates, nucleolus disappears, centriole start to move towards opposite poles and spindle fiber start to form

Question 19

What goes on during the metaphase of mitosis

Answer 19

• Centrioles are at opposite poles of the cell
• Spindle fiber maintain the chromosomes at the equatorial plane are are aligned in a single row
• Metaphase ends when centromere starts to divivde

Question 20

What goes on during the anaphase of mitosis?

Answer 20

• Centromere divides into two and sister chromatids separate
• Spindle fibers shorten, contract and sister chromatids are pulled to the opposite poles of the cell
• Anaphase ends when chromatids arrives at the pole of the cell

Question 21

What goes on during the telophase of mitosis

Answer 21

• When chromatids are at opposite poles, they are now called daughter chromosome
• Each pole contains one set of complete and identical chromosomes
• Chromosomes re-form as fine chromatin threads
• Nucleoli are formed again
• Spindle fibers disappear
• New nucleus membrane is formed
• Cytokinesis follows

Question 22

How does cytokinesis occur in animal cells?

Answer 22

• plasma membrane constricts in the middle of the cell between 2 nuclei
• Microfilaments at the point of constriction contract. causing the cell to constrict and split to form 2 daughter cells

Question 23

How does cytokinesis occur in plant cells?

Answer 23

• Formed vesicles combine to form cell plates at the centre of the cell
• Cell plates are surrounded by new plasma membrane and a new cell wall substance is formed among the spaces of the cell plates
• The cell plates expand outwards until they combine with the plasma membrane

Question 24

What is the necessity of mitosis?

Answer 24

Embryo development Produce new cells Stem cell therapy

Question 25

What is meiosis?

Answer 25

- Process of cell division that occurs in reproductive organs to produce gametes that contain half the number of chromosomes of parents cells

Question 26

Where does meiosis occur in male and female

Answer 26

Testis Ovary

Question 27

How does meiosis form gametes

Answer 27

- Through the process of gametogenesis - Ensures a diploid chromosome number in organisms

Question 28

What does Meiosis I and II comprise of?

Answer 28

Prophase I, Metaphase I, Anaphase I and Telophase I Prophase II, Metaphase II, Anaphase II and telophase II

Question 29

What are the 2 types of tumours?

Answer 29

Benign tumour Malignant tumour

Question 30

What are malignant tumours also called?

Answer 30

cancer

Question 31

What causes cancer?

Answer 31

Radiation Chemical substances Carcinogens Genetic factors Bacteria/viruses

Question 32

How is cancer harmful?

Answer 32

Spread and destroy normal cells around them Affect the function of tissues Damage to organs Death

Question 33

What causes down syndrome?

Answer 33

Abnormality during the division of Meiosis where spindle fibers fail to function during anaphase I or anaphase II which causes chromosomes to fail to separate

Question 34

What is the number of chromosomes in an individual with down syndrome? and what is this condition called?

Answer 34

47, trisomy 21

Question 35

What does down syndrome cause?

Answer 35

Mental retardation slanted eyes slightly protruding tongue