Mitotic Cycle

Question 1

Prophase

Answer 1

Super coiling of DNA
Nuclear membrane breaks down
Spindle develops and centrosome move to the poles

Question 2

Metaphase

Answer 2

Chromosomes line up along the equator

Microtubules attach to centromere

Question 3

Anaphase

Answer 3

Chromosomes pulled apart due to microtubules shortening

Question 4

Telophase

Answer 4

Chromosomes reach the poles and the nuclei reforms

Question 5

Cytokinesis

Answer 5

When the cytoplasm and cell splits

Question 6

Centromere

Answer 6

Middle bit of chromosomes

Question 7

Centrosome

Answer 7

Makes microtubules

Question 8

Centrioles

Answer 8

Two in centrosome, no function

Question 9

Phases of the cell cycle?

2

Answer 9

Mitosis- cell division, no growth

Interphase- normal cell activity

Question 10

What happens in interphase?

Answer 10

G1- cell undergoes majority of growth
S- each chromosome relocates (synthesis) to produce sister chromatids
G2- cell continues to grow and dna is checked for errors

Question 11

Structure of chromosome

Answer 11

Telomeres
Genes- each chromosome has several thousand
Centromere- holds the chromatids together, there are no genes here and it can be at any place in the chromosome
Chromatids- two identical chromatids make one chromosome, each contain one dna molecule

Question 12

Mitosis definition

Answer 12

A type of cell devision which results in two genetically identical daughter cells.

Question 13

When do cells duplicate their genetic material?

Answer 13

Before they divide so that each daughter cell receives an exact copy of DNA

Question 14

Mitosis-growth

Answer 14

The daughter cells formed have the same number of chromosomes as the parent cells and are genetically identical, allows multicellular organisms to result from a unicellular zygote.

Question 15

Mitosis- replacement of cells

Answer 15

Mitosis followed be cell devision. Cells are constantly dying and being replaced by identical cells ie skin which retain function

Question 16

Mitosis- asexual reproduction

Answer 16

The offspring are genetically identical to their parent. The production of new individuals of a species by a single parent.

Question 17

Mitosis- immune response

Answer 17

The cloning of B and T lymphocytes during the immune response is dependent on mitosis

Question 18

Telomeres- lots of info

Answer 18

They are at the end of genes. The copying enzyme cannot run to the end of the DNA, it stops a little short. By adding some more bases, without any useful information, to the end of the dna ensures that the copying enzymes copy’s all meaningful DNA. No vital info is lost when the DNA is replicated. Extra bases are added at each cell cycle by the enzyme telomerase to ensure it doesn’t run out.

Question 19

Telomeres- main function

Answer 19

To prevent the loss of genes during cell devision and to allow continual replication of a cell

Question 20

Cancer before it gets big

Answer 20

The result of uncontrolled mitosis, is caused by a change in the gene that controls cell devision. Most mutated genes die or are destroyed. An oncogene does not and reproduces by mitosis to form a tumour.

Question 21

What is the name of a mutated gene that causes cancer?

Answer 21

Oncogene

Question 22

Cancer after it’s a tumour

Answer 22

The tumour gets bigger and is supplied with blood and lymph vessels. The tumour cells spread in the blood and lymph to other parts of the body. Tumour cells invade other tissues.

Question 23

What is metastasis?

Answer 23

When secondary cancers form throughout the body

Question 24

What is the extent or the power of a stem cell to produce different cell types called?

Answer 24

Potency

Question 25

Totipotent

Answer 25

Stem cells which can produce any type of cell ie the zygote

Question 26

Pluripotent

Answer 26

Embryonic stem cells which lead to the development of the embryo

Question 27

Multipotent

Answer 27

Can only produce a few types of cells ie the bone marrow can only produce blood cells

Question 28

Stem cells

Answer 28

A cell that can decide an unlimited number of times, the new cell can remain a stem cell or develop into a specialised cell. As cells become more specialised they loose their ability to devide till they can’t. A small population of stem cells remain which can produce new cells.

Question 29

Chromatin

Answer 29

DNA+ proteins (histones)
Histones are basic so interact with DNA
Packed very closely 
Makes up chromosomes 
In subunits known as nucleosomes