Meiosis + Mitosis

Question 1

What is Mitosis and what are its stages

Answer 1

The separation of nuclear chromosomes to form 2 identical daughter nuclei
Interphase
Prophase
Metaphase
Anaphase
Telophase

Question 2

Interphase

Answer 2

The genetic material of the cell increases. The cell makes a copy of its DNA before division begins so each single stranded chromsome becomes double stranded. This is the state a cell spends most of its time in where growth and repair takes place.

Question 3

Prophase

Answer 3

Chromatin condenses and becomes short and thick to form chromosomes. Each chromosome has 2 sister chromatids joined together at the centromere. The nuclear membrane begins breaking down and the centrioles move away from one another to the opposite poles as spindle fibers begin to form.

Question 4

Metaphase

Answer 4

The microtubule from each centtriole attaches from the centromere from either side pulling on the chromosome. This causes the chromosomes to line up in the equator of the cell

Question 5

Anaphase

Answer 5

Spindle fibres contract and with it one chromatid from each chromosome
is pulled to opposite poles of the cell as centromeres are split.

Question 6

Telophase + Cytokinesis

Answer 6

The chromatids (bc they r spereated they r chromosomes again) arrive at the poles and begin to decoil to reform chromatin,The spindle fiber begins to disappear and the nuclear membrane begins reforming around the newly reformed chromatin. The centrioles go to each daughter cell.

Cytokinesis occurs where 2 identical daughter cells are produced.

Question 7

Importance of mitosis in Growth Repair Asexual Reproduction and Immune Response

Answer 7

Growth-Humans begin life as a single cell whoch divides to form millions of cells in the human body in which all cells have the same number of chromosomes.In animal growth takes place all over the body while in plants it only happens in specific regions known as meristems

Repair- Mitosis causes Tissue repair. When the skin is cut mitosis creates identical cells to cover the wound and can join the edges together

Asexual Reproduction-Mitosis can cause new organisms to be formed from a single adult where the cells of that organism are gentically identical to its parent.

Immune Response- When lymphocytes come into contact with bacterium carrying particular antigens mitosis will allow the lymphocyte to divide and create a large population of genetically identical plasma cells that will produce the antibody needed to destroy the bacteria

Question 8

What is a homologous chromosome

Answer 8

A pair of chromosomes that share the same gene from each parental source in the same position on the chromosome.

Question 9

What is Meiosis and the stages

Answer 9

Meosis is a special type of cell division which produces sex cells known as gametes. These cells make reproduction possible when the sperm fuses with the egg to form a new organism. Each sex cell contains 23 chromosomes so that when fused they make up the total 46 chromosomes within the new organism. Where it gains 23 from its mother and 23 from its father.

Meosis contains 2 stages- Meosis 1 and 2
Both contain
Prophase 1 and 2
Metaphase 1 and 2 
Anaphase 1 and 2
Telohase 1 and 2

Question 10

Prophase 1

Answer 10

The chromosomes condense and join together to form homologous pairs.Each pair containing 1 chromosome from the father and 1 from the mother with different copies of the same genes. Genes are swapped within each pair in a process known as crossing over and the nucleus begins breaking down.

Question 11

Metaphase 1

Answer 11

The pairs of chromosomes line up in the equator of the cell. The spindle fibers attach to themselves to 2 bodies on opposite sides of the cell.

Question 12

Anaphase 1

Answer 12

The fibers seperate the pairs by contracting and pulling them apart

Question 13

Telophase 1

Answer 13

The nuclei reforms as the chromosomes begin to decoil and the cell begins to split in 2. Each cell contains 23 double stranded stranded chromosomes.

Question 14

Meiosis 2

Answer 14

One single diploid cell will be divided to form 4 haploid cells=Each newly divided cell will divide again to form 4 new cells that contain 23 single stranded chromosomes. When the nuclei of 2 gametes fuse the diploid number is restored forming a zygote where there would be a copy of a chromosome from each parent (homologous chromosomes).These 4 sex cells produces are gentically different to one another and are geneticllay different to the original cell which accounts for the reason why siblings look and act different to one another.
MEIOSIS 2 IS BASICALLY JUST MITOSIS-SAME PMAT SHIT

Question 15

2 processes that leads to variation in meiosis

Answer 15

Independent Assortment

Crossing Over

Question 16

Independent Assortment

Answer 16

In metaphase 1 homologous pairs line up at the metaphase plate. How one pair of chromosomes behaves does not affect how another would behave. How one pair seperates does not affect how another pair would seperate. Segregation of paternal and maternal copies would happen at random. Alleles from both organisms are mixed. The direction the chromosome is going to assort happens in metaphase 1 and the actual assorting happens in anaphase 1.

Question 17

Crossing Over

Answer 17

This process takes place in Prophase 1 when homologous pairs find each other. Non sister chromatids can become tangled resulting in a break in the 2 known as chiasma. The pieces switch chromosomes and reattach resulting in chromosomes with a different arrangement of alleles on each one.The new arrangement has part maternal and part paternal constitution.