mitosis

Question 1

define interphase

Answer 1

-interphase is an active period where protein synthesis by ribosomes, dna replication and increase in number of mitochondria and chloroplast in plant cells occur.

Question 2

define homologous chromosomes and mitosis

Answer 2

-chromosomes of the same length and shape having same genes from gene loci
-production of two genetically identical cells, each containing a complete copy of parental chromosomes from a parent cell

Question 3

recite prophase

Answer 3

-chromatin thread condenses, coils and shortens to become chromosomes, each consisting of two sister chromatids attached at the centromere, now visible under microscope
-asters made of microtubules form around centrioles
-two pairs of centrioles move apart to opposite poles of the cell, forming spindle fibres between them
-nucleolus disappears
-nuclear envelope disappears
-spindle forms with spindle fibres extending from one pole of the cell to the other

Question 4

recite metaphase

Answer 4

-chromosomes line up at the equator of the spindle
-centromere of each chromosome is attached to a spindle fibre

Question 5

recite anaphase

Answer 5

-each centromere splits
-spindle fibres pull chromatids apart to opposite poles of the cell
-once chromatids are separated, now known as daughter chromosomes

Question 6

recite telophase

Answer 6

-spindle fibres break down
-nuclear envelope forms around chromosomes at opposite poles of the cell
-nucleolus forms and the chromosomes uncoil and lengthen to become chromatin threads

Question 7

differentiate chromosomes and sister chromatids

Answer 7

-two dna molecule formed during DNA replication are known as sister chromatids until they are separated at the centromere during anaphase, thereafter they are known as daughter chromosomes

Question 8

recite cytokinesis

Answer 8

-division of cytoplasm
-furrow appears in cytoplasm between the two nuclei, deepens to produce two identical cells
-does not take place in plant cells, instead a cell plate forms between the two nuclei by fusion of fluid filled vesicles

Question 9

explain the importance of mitosis with regards to growth, repair and an increase in mass, as well as in asexual reproduction

Answer 9

-for growth to occur, cells divide through mitosis and new cells are differentiated to form tissues and organs
-growth in plants only tip of shoot and root, animal is occur throughout body, plant growth occur throughout lifetime, animal is stop after maturity
-multicellular organisms depend for development of zygote to embryo
-unicellular organisms, mitosis reproduces entire organism which is genetically identical to parent

Question 10

explain how planarian worm is an example of mitosis for repair

Answer 10

-class of worm that is able to regenerate parts of body when cut into another genetically identical organisms through undergoing mitosis under the area of wound