4.4.3 - Inheritance

Question 1

Where is the genetic material found in a Eukaryotic cell?

Answer 1

The nucleus

Question 2

Define the term chromosome.

Answer 2

A structure made from a long strand of DNA

Question 3

Define the term gene.

Answer 3

A section of the DNA that codes for a protien.

Question 4

Define the term genome.

Answer 4

All of the genetic material in an organism.

Question 5

What shape is a DNA molecule?

Answer 5

Double Helix

Question 6

How many chromosomes are found in normal human body cells?

Answer 6

46, 23 pairs

Question 7

What is a gamete?

Answer 7

A sex cell

Question 8

How many chromosomes are found in human gametes?

Answer 8

32

Question 9

Define the term haploid.

Answer 9

Half the chromosomes

Question 10

Define the term diploid.

Answer 10

Full number of chromosomes.

Question 11

Describe how Meiosis creates gametes.

Answer 11

• A normal diploid cell divides into 2 identical daughter cells
• These cells divide into 4 haploid daughter cells that are genetically different

Question 12

What is the human genome project?

Answer 12

A project to map all the genes in a human genome.

Question 13

Which pair of chromosomes define the sex in humans?

Answer 13

Pair 23.
X and Y

Question 14

Define the term genome.

Answer 14

The alleles that an organism has for a particular characteristic.

Question 15

Define the term phentotype.

Answer 15

The visible characteristics of an organism as a result of their genotype.

Question 16

What are the female sex chromosomes?

Answer 16

XX

Question 17

What are the male sex chromosomes?

Answer 17

XY

Question 18

What is fertilisation?

Answer 18

The joining of the male (sperm) and female (egg) sex cells and the nuclei fuse.

Question 19

Define the term allele.

Answer 19

Different forms of the same genes

Question 20

Define the term Dominant.

Answer 20

The allele would be present even if there is only one

Question 21

Define the term Recessive.

Answer 21

The allele would be only present if it is two of the same.

Question 22

Define the term polygenic.

Answer 22

A characteristic controlled by more than one pair of genes.

Question 23

How are identical twins formed?

Answer 23

The fertilised egg splits into two gametes.

Question 24

How are non-identical twins formed?

Answer 24

Two eggs are fertilised at once.

Question 25

If a characteristic is controlled by a recessive allele, what must the genotype of that individual be? (use b/B)

Answer 25

bb

Question 26

In the case of birds, having short feathers is dominant and having long feathers is recessive. What are the 3 possible allele combinations a bird could be and what kind of feathers will each have?

Answer 26

- BB = short feathers - Bb = short feathers - bb = long feathers

Question 27

Define the term Homozygous.

Answer 27

A pair of alleles that are the same (aka bb or BB)

Question 28

Define the term Heterozygous.

Answer 28

A pair of alleles that are different (aka Bb)

Question 29

Using the letter B/b, write out the 3 possible combinations of alleles.

Answer 29

- BB - Bb - bb

Question 30

If a characteristic is controlled by a recessive allele, what must the genotype of that individual be?

Answer 30

bb

Question 31

If a characteristic is controlled by a dominant allele, what could the genotype of that individual be?

Answer 31

BB or Bb

Question 32

What is variation?

Answer 32

Differences between individuals.

Question 33

What are the 2 possible causes of variation?

Answer 33

- Genetic - Environmental

Question 34

Name a characteristic that is controlled by both causes of variation.

Answer 34

Hair colour