Genetics

Question 1

What is cell division

Answer 1

When a cell makes a genetically identical copy of itself

Question 2

Why do cells divide?

Answer 2

To grow, repair tissue and develop or change

Question 3

What are homologous chromosomes?

Answer 3

Pairs of chromosomes that carry corresponding DNA. One member of each pair comes from male and female

Question 4

Explain what diploid sand haploid are

Answer 4

D: the number of chromosomes (2N) found in each cell of a given species. Includes homologous pairs.
H: the number of unpaired chromosomes (N) found in an egg or sperm cell

Question 5

How much is each stage of the cell cycle

Answer 5

90% interphase, 10% mitosis

Question 6

What are chromatin

Answer 6

DNA and protein. The state of chromosomes during interphase

Question 7

Explain interphase

Answer 7

Strands of DNA separate, creating an exact copy of itself. Now referred to as sister chromatids which are joined by a centromere.

Question 8

Go through stages of interphase

Answer 8

G1 phase: cytoplasm and organelles are produced
S phase: synthesis, DNA replicates
G2: remakes materials used in s phase. Now in 4N stage

Question 9

Explain each stage of mitosis

Answer 9

Prophase: chromosomes become visible when chromatin shortens and thickens. Chromatid pairs form.
Metaphase: chromatid pairs line up in centre of cell.
Anaphase: pairs separate
Telophase: cytoplasm Serpentes and two nuclei form.

Question 10

Explain mitosis 1 of meiosis

Answer 10

Prophase I: chromatin shortens and thickens to become visible. Synapsis (crossing over) occurs. Homologous pairs sort together.
Metaphase I: chromosomes in tetrads line up on equator of cell. Nuclear membrane is gone and spindle fibres have been formed.
Anaphase I: homologous pairs break up into separate double strand chromosomes.
Telophase I: nuclei reassembled. Cytoplasm divides.

Question 11

Explain mitosis II of meiosis.

Answer 11

Prophase II: homologous pairs organize
Metaphase II: homologous pairs line up in centre
Anaphase II: chromatids divide in half
Telophase II: nuclei reform and cytoplasm divides. N stage is formed and interphase begins again.

Question 12

Explain the law of independent assortment.

Answer 12

The direction in which maternal and paternal chromosomes migrate is random. Creates variation.

Question 13

Explain synapsis.

Answer 13

Non-sister chromatids break and rejoin, exchanging DNA segments. The resulting chromosome will have DNA from both maternal and paternal chromosomes. Creates variation.

Question 14

What is nondisjunction?

Answer 14

when homologous chromosomes do not
separate correctly in anaphase I (or when sister chromatids do not separate correctly in anaphase II)
This results in some gametes having too many chromosomes and some gametes having too few chromosomes

Question 15

What is trisomy and monosomy?

Answer 15

Trisomy: having an extra chromosome
Monosomy: having one less chromosome

Question 16

Explain Down syndrome.

Answer 16

Trisomy of chromosome 21. Characterized by intellectual disabilities and almond shaped eyes.

Question 17

Give examples of sex-linked traits.

Answer 17

• colour blindness
• hemophilia
• male-pattern baldness
• hairy pinna

Question 18

Explain incomplete dominance and co-dominance

Answer 18

Incomplete: one allele doesn’t dominate over another allele completely, creating a new phenotype. Example: red and white forming pink.
Co-dominance: alleles in a heterozygote are both fully expressed

Question 19

Define alleles.

Answer 19

A variant of a gene. Can have different phenotypic expression. Example: gene for eye colour can have an allele for brown or blue.

Question 20

What are hybrids?

Answer 20

Offspring of parents that differ in genetically determined traits.

Question 21

What is a pedigree

Answer 21

Diagram that shows the lineage of a family and its genealogy.

Question 22

What is the universal blood donor type? Recipient? Why?

Answer 22

Donor: O is compatibility with any blood type. Has no anti b or anti a reactions.
Recipient: AB. Can receive any blood type, as it contains no antibodies.

Question 23

How can we determine our blood type using antigens?

Answer 23

Our blood produces antigens of our blood type. If you produce A antibodies, you have type A blood. B is B, A and B is Ab and none is O.

Question 24

What happens if you receive a transfusion of the wrong blood type?

Answer 24

Your body produces anti bodies against any blood types that aren’t yours. If you receive the wrong blood type, your immune system will attack the new blood cells, destroying them and not allowing you to receive enough blood.

Question 25

What are antibodies? Antigens?

Answer 25

Antibodies work in the immune system to counter antigens. Antigens are foreign substances that create an immune response in the body.