2.2 Mitosis And Cell Cycle

Question 1

Interphase

Answer 1

DNA replication
Organelle replication

Question 2

Prophase

Answer 2

-Chromosomes condense
-nucleus starts to break down (nuclear membrane)
-spindle fibres start to form

Question 3

Metaphase

Answer 3

-spindle fibres attach to centromere
-chromosomes line up along the equator

Question 4

Anaphase

Answer 4

-centromere spilts
-Spindle fibres shorten
-sister chromatids move to opposite poles

Question 5

Telaphase

Answer 5

-spindle fibres break down
-new nuclei form (one for each set of chromosomes

Question 6

What is a product of mitosis

Answer 6

Two identical daughter cells

Question 7

How would you work out how long one stage of mitosis takes

Answer 7

Humber of cells in stage/
total number of cells x
One cell cycle time

Question 8

How is cancer most likely caused

Answer 8

A gene mutation

Question 9

What is a mutation

Answer 9

Change in the base sequence of DNA

Question 10

What is cancer (long answer)

Answer 10

-A breakdown in the cellular control mechanism that puts the brakes on cell division
-Cells that should be stable begin to divide and form a tumour
(A tumour is a congregation that can occur almost anywhere in the body, and is made up of abnormal cells that divide constantly)

Question 11

What is the difference between benign and melignant tumours

Answer 11

Benign are slow growing harmless and contained in the membrane where as malignant are quickly growing and harmful because of where they grow

Question 12

What cell division happens in prokaryotes

Answer 12

Binary fission

Question 13

What happens in binary fission

Answer 13

1- circular DNA replicates and attached to either end of the cell membrane
2- plasmids replicate
3- cell membrane expands, piverting inwards and diving the cytoplasm in 2
4- cell wall forms between the two molecules of DNA, dividing the original cell into 2 identical daughter cells

Question 14

Similarities between binary fission and mitosis

Answer 14

-two identical daughter cells formed
-both types of asexual reproduction

Question 15

Differences between mitosis and binary fission

Answer 15

-no organelles replicated in binary fission
-spindle fibres not required in binary fission
-prokaryotes do not have nucleus’s (binary fission)
-no metaphase in binary fission

Question 16

What happens in viral replication

Answer 16

1) Virus exploits the cell receptors by attaching to the cell with their complementary attachment proteins
2) Vircal DNA and core proteins are released into the cytoplasm where reverse transcriptase converts the viral RNA to DNA
3) Viral RNA is inserted into the nucleus
4) viral components are replicated
5) they assemble and lyse the cell
6) where they will attempt to infect another cell