Inheritance

Question 1

Which scientist first discovered the basis of genetics?

Answer 1

Gregor Mendel

Question 2

Which plant did Mendel use for scientific studies?

Answer 2

Peas

Question 3

What is an allele?

Answer 3

A different version of the same gene

Question 4

What is a gene?

Answer 4

A section of DNA which codes for a protein/characteristic

Question 5

What is a chromosome?

Answer 5

A length of DNA, packaged with proteins

Question 6

What is an organism’s genotype?

Answer 6

The alleles that the organism has

Question 7

What is an organism’s phenotype?

Answer 7

The physical characteristics an organism has

Question 8

What does it mean if an allele is dominant?

Answer 8

It is always expressed

Question 9

What does it mean if an allele is recessive?

Answer 9

It is only expressed when there are two of them

Question 10

How many alleles of each gene does a human have?

Answer 10

2; 1 from mother and 1 from father

Question 11

What does it mean if a person has heterozygous alleles?

Answer 11

The two alleles are different

Question 12

What does it mean if a person has homozygous alleles?

Answer 12

the two alleles are the same

Question 13

How would you describe a person who had the alleles BB?

Answer 13

Homozygous dominant

Question 14

How would you describe a person who has the alleles Bb?

Answer 14

Heterozygous

Question 15

How would you describe a person who has the alleles bb?

Answer 15

Homozygous recessive

Question 16

Which two alleles are used to represent biological sex?

Answer 16

X and Y

Question 17

Is XX male or female?

Answer 17

Female

Question 18

Is XY male or female?

Answer 18

Male

Question 19

Which 3 alleles code for different blood groups?

Answer 19

A, B and O

Question 20

Which blood group allele is recessive?

Answer 20

O

Question 21

What does it mean if genes are codominant?

Answer 21

Two dominant genes are expressed simultaneously. E.g. in blood groups, A and B can both be expressed (Blood type AB)

Question 22

Alleles for sex-linked disorders are usually located on which chromosome?

Answer 22

X

Question 23

Why are males more likely to suffer from a sex-linked disorder?

Answer 23

Sex-linked disorders are caused by recessive alleles on the X chromosome. Females have two X chromosomes so would need to inherit the allele from both parents. Males only have 1 chromosome so inherit the allele from their mother.

Question 24

What causes genetic variation?

Answer 24

mutations and random sorting of chromosomes during meiosis and sexual reproduction

Question 25

What is a mutation?

Answer 25

A change in DNA sequence

Question 26

What causes environmental variation?

Answer 26

Differences in environment

Question 27

Are all mutations negative?

Answer 27

No. Some can be beneficial (e.g. antibiotic resistance in bacteria), some will have no effect and some will cause a change which is neither positive or negative (e.g. different eye colours)