4.2 Asexual reproduction

Question 1

Cell division

Answer 1

Cells (eukaryotic) divide during mitosis (nuclear division) and cytokinesis (cytoplasmic division)
Cell division produces two daughter cells that are genetically identical to each other and the parent cell

Question 2

What are chromosomes made of

Answer 2

bodies of tightly bound DNA

Question 3

How many chromosomes in your body

Answer 3

In your somatic (body) cells, you have 46 chromosomes.
That is 23 pairs of chromosomes. One chromosome in each pair is from each of your biological parents.

Question 4

Mitosis

Answer 4

During regular cell division, each chromosome duplicates
The sister chromatids (copies of the chromosome) are joined by a centromere

Question 5

0. Interphase

Answer 5

During interphase genetic material in the form of thread-like chromatin is duplicated (replication)
This results in the pairs of sister chromatids.

Question 6

1. Prophase

Answer 6

During prophase the chromatin (chromosomes) shorten and thicken and are visible under a microscope
Centrioles (in animal cells) separate and move to opposite ends of the cell
Nuclear membrane starts to dissolve

Question 7

2. Metaphase

Answer 7

Spindle fibers move and align chromosomes (each composed of sister chromatids) in the centre (equator) of the cell

Question 8

4. Telophase

Answer 8

Chromosomes reach opposite poles of the cell and begin to disappear (go back to being chromatin)
Spindle fibers disappear
Nuclear membrane re-forms
Two identical daughter cells are now present

Question 8

3. Anaphase

Answer 8

Sister chromatids divide (now called chromosomes)
Sister chromatids split at the centromere and move to opposite poles of the cell
If mitosis proceeds correctly, the same number of chromosomes will be found at each pole of the cell

Question 9

4b. Cytokinesis

Answer 9

The cell divides its cytoplasm and organelles into two new daughter cells
In many cells (protists, fungi & animal cells) a furrow develops
In plant cells, a cell plate appears on the equator. This becomes the cell wall

Question 10

Biotechnology definition

Answer 10

The field of biology that involves the use of living things in engineering, industry and medicine

Question 11

Plant cloning

Answer 11

In 1958, carrot plants were first cloned in labs
Cells are placed in a growth medium, which allows them to grow into small plants
Plants are identical

Question 12

Animal cloning

Answer 12

1996, Dolly was the first mammal to be cloned from an adult body cell.
The process involved substituting the desired nucleus in place of the original nucleus

Question 13

Why cloning?

Answer 13

Mass production of livestock and crop plants
Cloning genetically modified organisms (GMOs) Table 1
Cloning endangered species