Mitosis

Question 1

what happens during prophase

Answer 1

-Chromosomes condense and become visible(each consisting of two sister chromatids joined at the centromere)

-The nuclear envelope breaks down.

-The nucleolus disappears.

-Centrioles move to opposite poles and spindle fibers (microtubules) form.

Question 2

what happens during metaphase

Answer 2

-Spindle fibers are fully formed and attached to the centromeres of the chromosomes.

-Chromosomes align at the equator of the cell

Question 3

what happens at telophase

Answer 3

-Chromosomes arrive at opposite poles and begin to decondense.

-A nuclear envelope reforms around each set of chromosomes, and nucleoli reappear.

-The spindle fibers disintergrate

Question 4

what happens during cytokineses

Answer 4

-This is the final stage where the cytoplasm divides to form two genetically identical daughter cells.
-(A furrow forms and deepens in animal cells, while vesicles form a cell plate in plant cells.)

Question 5

what is interphase

Answer 5

-I during which a cell grows, duplicates its organelles, and replicates its DNA in preparation for division

Question 6

what is the purpose of mitosis

Answer 6

growth
repair
reproduction

Question 7

what is binary fission

Answer 7

The process by which prokaryotic cells divide

Question 8

how does binary fission occur

Answer 8

-circular DNA replicates and both copies attach to the cell membrane (plasmids also replicate)
-the cyptoplasm begins to split into two
-a new cell wall forms between the two DNA molecules dividing the original cell
-The identical
daughter cells each have a single copy of the circular DNA and a variable number of copies
of the plasmids.

Question 9

Describe the stages that of the cell cycle that occurs in eukaryotic cells that do retain the ability to divide

Answer 9

G1-synthesises new proteins and enzymes making the cell ready for DNA replication
S-the cel replicates its DNA
G2-cell continues to grow and synthesise proteins required for cell division
Prophase-Chromosomes condense become visible,nucleolus disappears and nuclear envelope disintergrates ,centrioles form the spindle fibres
Metaphase-chromosomes line up along the equator,each chromosome lines up with spindle fibres
Anaphase-chromosomes divide and spilt to opposite poles of the cell
Telophase-spindle fibres disintergrate,nucleolus forms around two sets of chromosomes,chromosomes decondense
Cytokenisis-cytoplasm divides and the cells become two identical cells

Question 10

Describe the behaviour of chromosomes during interphase, prophase, metaphase, anaphase and telophase of mitosis.

Answer 10

Interphase
Dna in the chromosomes duplicate,each chromosome now consists of two identical sister chromatids joined at the centromere
Prophase
Chromatin condenses and coils tightly, becoming shorter,each chromosomes connect at the centromere
Metaphase
The chromosomes line up at the equator of the cell, centromere attatch to the chromosomes
Anaphase
Chromosomes split and go to opposite ends of cells
Telophase
chromosomes decondense

Question 11

Describe the role of spindle fibres attached to centromeres in the separation of chromatids.

Answer 11

pull sister chromatids to opposite poles of the cell, ensuring each daughter cell receives an identical set of chromosomes

Question 12

State what occurs during cytokinesis.

Answer 12

the cytoplasm divides to form two identical daughter cells

Question 13

how do viruses replicate

Answer 13

attatchment proteins attatch to the cell receptors
virus moves in via endocytosisthen replicates its dna
host cells uses genetic information to synthesise new viral proteins
components reasemble and exit the cell