B10: Variation And Inheritance

Question 1

Allele

Answer 1

A version of a particular gene

Question 2

Gene

Answer 2

A short section of DNA carrying genetic information.

Question 3

How many chromosomes in a sex cell?

Answer 3

23

Question 4

How many chromosomes in a body cell?

Answer 4

46, 23 pairs

Question 5

List chromosomes, DNA and genes from largest to smallest.

Answer 5

Chromosome
Gene
DNA

Question 6

2 factors that cause variety.

Answer 6

Genes

Environment

Question 7

Female Chromosomes

Answer 7

XX

Question 8

Male Chromosomes

Answer 8

XY

Question 9

Heterozygous

Answer 9

Having 2 different alleles for the same gene

Question 10

Genotype

Answer 10

Whether a person is homozygous or heterozygous for a particular characteristic.

Question 11

Phenotype

Answer 11

Describes the physical appearance of an individual.

Question 12

DNA meaning

Answer 12

Deoxyribonucleic Acid

Question 13

Bases

Answer 13

Nitrogenous compounds that make up part of the DNA structure.

Question 14

How many bases on DNA code for one amino acid?

Answer 14

3

Question 15

How do bases match up?

Answer 15

A pple T art

C hocolate G ateau

Question 16

What causes Downs Syndrome?

Answer 16

An extra copy of chromosome 21. (Having 47 chromosomes)

Question 17

Huntingtons

Answer 17

A disorder that wastes away parts of the brain.

Dominant.

Question 18

Sickle Cell Anaemia

Answer 18

Causes sickle shaped red blood cells which don’t transport oxygen efficiently.
Recessive.

Question 19

Cystic Fibrosis

Answer 19

Affects the lungs, digestive and reproductive systems.

Recessive.

Question 20

Polydactyly

Answer 20

Causes extra fingers and toes.

Dominant.

Question 21

Amniocentesis

Answer 21

15-16 weeks.

Fluid is taken from around the foetus.

Question 22

Chorionic Villus Sampling

Answer 22

10-12 weeks.

Small sample is taken off of the tissue of the developing placenta.

Question 23

Concerns with embryo screening

Answer 23

> Can sometimes give false results.
People would decide to terminate and otherwise healthy pregnancy.
Could lead to designer babies.

Question 24

Homozygous.

Answer 24

Having 2 identical alleles for the same gene

Question 25

How can embryos be screened for genetic disorders?

Answer 25

DNA isolated from embryo
(fluorescent) probe mixed with embryo DNA
probe (then) binds with embryo DNA
(UV light) to show alleles / gene for disorder