2.2 Chromosomes, Genes and DNA.

Question 1

What are basic biological units known as?

Answer 1

Cells.

Question 2

List some examples of cells.

Answer 2

skin cells
stem cells
blood cells
nerve cells
fat cells
muscle cells.

Question 3

What does DNA stand for?

Answer 3

deoxyribonucleic acid

Question 4

Where is DNA located in the cell?

Answer 4

The nucleus.

Question 5

What is hierarchical relationship between Cells, Nuclei, Chromosomes, Genes, DNA, Nucleotides

Answer 5

Biggest to smallest (for lack of a better term)

Question 6

What are genes made up of?

Answer 6

Sections of DNA.

Question 7

Each genetic instruction that codes for a particular ____ is called a gene.

Answer 7

Trait

Question 8

What is the location of a gene on a specific chromosome called.

Answer 8

Locus

Question 9

Genes that are located on the same chromosome are described as being ____

Answer 9

Linked.

Question 10

What do genes do?

Answer 10

They contain the instructions for making a particular protein (polypeptide)

Question 11

How many chromosome do most people have?

Answer 11

46

Question 12

Why aren’t chromosomes visible when cells aren’t divided?

Answer 12

It is because the coils are unwound and the DNA is spread throughout the nucleus.

Question 13

What are chromatids?

Answer 13

They are two identical threadlike strands that the chromosome divides into during cell division.

Question 14

Are sister chromatids identical?

Answer 14

YES

Question 15

What is the centromere (in the chromosome)?

Answer 15

It is the region where two sister chromatids and the long and short arms of the chromosomes join.

Question 16

What is the telomere (in the chromosome)?

Answer 16

It is the cap on the end of each chromosome.

Question 17

What is the kinetochore (in the chromosome)?

Answer 17

It is associated with the centromere and assists with cell division.

Question 18

Where are each (4) parts of the chromosome located.

Answer 18

Centromere - Middle
Telomere - Ends of the chromosomes.
Chromatids - made up of half of the chromosome (one short and one long arm)
Kinetochore - Around the centomere.

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Question 19

Differences between autosomes and sex chromosomes.

Answer 19

Sex chromosomes:
- Either X or Y.
- Only 2 in the body.
- Differ between men and women.

Autosomes:
- All present in a regular person.
- 44 total.
- Present in both men and women.

Question 20

What are somatic cells?

Answer 20

Non-sex cells.

Question 21

How are autosomes organised?

Answer 21

Organised into 22 pairs on the basis of their relative size, position of centromere and stained banding patterns.

Chromosome 1: Largest.
Chromosome 22: Smallest.

Question 22

What are the members of matching pairs of chromosomes described as?

Answer 22

Homologous.

Question 23

What do sex chromosomes determine?

Answer 23

Gender (sex)

Question 24

What are XY and XX chromosomes mean?

Answer 24

XY: Male
XX: Female

Question 25

What is a karyotype?

Answer 25

It is an image that orders chromosomes based on size.

Question 26

What are mitosis and meiosis and what is the difference?

Answer 26

These are two types of cell division involved in cell production.
Mitosis is used in somatic cells for replacement, growth and repair.
Meiosis is used in sex cells to produce to new gametes (sperm and ova).

Question 27

What is the difference in the result of meiosis compared to mitosis?

Answer 27

Meiosis results in the chromosome number being halved meaning only one chromosome from each pair in created.

Question 28

How is genetic information passed on in fertilisation?

Answer 28

23 chromosomes in the sperm and 23 in the ova. They fuse together during fertilisation to make 23 pairs (one chromosome from each parent).