SB3a-b

Question 1

What is asexual reproduction? (6 points)

Answer 1

1. Done by some animals such as invertebrates (insects) and some plants.
2. Does not involve gametes, only 1 parent.
3. Offspring inherits characteristic from one parent.
4. No variation since offspring is genetically identical to parent (clone).
5. Involves only mitosis.
6. Much faster than sexual reproduction.

Question 2

What is sexual reproduction? (6 points)

Answer 2

1. Done by most animals and plants.
2. Involves gametes (egg cells, sperm cells, pollen grains).
3. Offspring inherits characteristics from both parents.
4. Leads to variation, meaning organisms have different characteristics and allows them to survive in different/new conditions.
5. Involves meiosis and mitosis.
6. Slower than asexual reproduction.

Question 3

How is a zygote created?

Answer 3

When the sperm cell fertilizes the egg cell.

Question 4

How does a zygote become an embryo?

Answer 4

It undergoes mitosis.

Question 5

What is a genome?

Answer 5

The DNA of an organism.

Question 6

What is carried by the DNA?

Answer 6

Instructions for all the proteins the body needs to make.

Question 7

What is the polymer of proteins?

Answer 7

Amino acids.

Question 8

What happens during the first stages of meiosis?

Answer 8

Prophase I: Chromosomes condense and coil to become visible, then pair up to form homologous pairs. The pairs cross over, exchanging genetic material.

Metaphase I: Spindle fibres form and attach on the centromere and chromosomes line up as homologous pairs in the middle of the cell.

Anaphase I: Spindle fibres contract separating the pairs and each chromosome moves to opposite sides of the cell.

Telophase I: Nuclear membrane reforms and chromosomes un-condense and uncoil.

Cytokinesis: Cell divides forming two cells.

Question 9

What happens during the second stages of meiosis?

Answer 9

Prophase II: Chromosomes condense and coil to become visible.

Metaphase II: Spindle fibres form and attach on the centromere and chromosomes line up in the middle of the cell.

Anaphase II: Spindle fibres contract pulling the sister chromatids apart, breaking the centromere and chromatids move to opposite sides of the cell.

Telophase II: Nuclear membrane reforms and chromosomes un-condense and uncoil.

Cytokinesis: Cell divides and forms 4 haploid, non-identical daughter cells.