cell division 🤑

Question 1

what are the phases of the cell cycle?

Answer 1

1) interphase
(mitosis:)
2) prophase
3) metaphase
4) anaphase
5) telophase
6) cytokinesis

Question 2

describe what happens during interphase

Answer 2

DNA exists as long and thin chromatin when cell is not dividing, organelles duplicate.
DNA replication takes place during interphase to produce two identical chromation threads joined at the centromere.
a pair of centrioles divides into two pairs.

Question 3

define mitosis

Answer 3

mitosis is a process of nucleur division involving the equal division of one nucleus into two genetically identical nuclei, producing two genetically identical daughter cells

Question 4

describe what happens during prophase

Answer 4

• chromatin condense, coil and shorten to form chromosomes (each chromosome consist of two genetically identical sister chromatids attached at the centromere)
• nucleolus and nucleur envelope disintegrate
• centrioles move to to opposite ends of the cell and spindle fibres form from each pair of centrioles

Question 5

describe what happens during metaphase

Answer 5

• chromosomes line up at the equator of the cell
• spindle fibres atttach to the centromeres

Question 6

describe what happens during anaphase

Answer 6

• each centromere splits
• spindle fibres pull sister chromatids appart to opposite poles of the cell

Question 7

describe what happens during telophase

Answer 7

• chromosomes reach the poles of the cell
• chromosomes decondense to form chromatin
• nucleur envelope re-forms around the chromosomes at each pole

Question 8

define cytokinesis

Answer 8

cytokinesis is the division of the cytoplasm to produce two completely separated daughter cells

Question 9

describe what happens during cytokinesis in animal cells

Answer 9

• cleavage furrows appear between the two nuclei in cytoplasm
• cleavage furrow deepens until the parent cell pinches into two daughter cells

Question 10

describe what happens during cytokinesis in plants

Answer 10

a cell plate forms by the fusion of the vesicles containing cellulose produced by the Golgi apparatus

Question 11

what is the importance of mitosis?

Answer 11

to maintain genetic stability with identical chromosomal numbers and exact genetic information
- for growth, repair and asexual reproduction

Question 12

explain the need for production of genetically identical cells

Answer 12

so that the new cells can carry out the same function, and daughter cells contain all the DNA needed for subsequent function, cell division and differentiation

Question 13

haploid vs diploid cells

Answer 13

haploid cells, gametes, have 23 chromosomes while diploid have 46 chromosomes

Question 14

what are homologous chromosomes?

Answer 14

homologous chromosomes are a pair of chromosomes having identical structural features (one from father, one from mother)
- same size and shape
- same centromere position
- genes for the same features are at the same position on the chromosome