Inheritance

Question 1

Why are people different?

Answer 1

Because they inherit different characteristics (or traits) from their parents

Question 2

What are examples of inherited characteristics?

Answer 2

eye colour, earlobe shape

Question 3

What are inherited characteristics?

Answer 3

Characteristics which are only determined by genes

Question 4

What are examples of acquired characteristics?

Answer 4

Scars, hair length, etc

Question 5

What are acquired characteristics?

Answer 5

Other characteristics that are not inherited, which depend on environmental factors.

Question 6

What is a phenotype?

Answer 6

observable characteristics or traits of individuals

Question 7

What is a genotype?

Answer 7

Actual genetic information carried by individuals that are not gained through the environment.

Question 8

A phenotype depends on ___ + ___

Answer 8

genotype + environmental factors

Question 9

What are genes?

Answer 9

The basic unit of inheritance which is a segment of DNA which controls one specific characteristic.
They contain codes needed to produce proteins.

Question 10

What is a locus?

Answer 10

A gene’s location which is located on the same position on the same chromosome.

Question 11

What are Alleles?

Answer 11

Variations of genes which occupy the same position on homologous chromosomes.

Question 12

What do alleles hold?

Answer 12

different genetic information for the same characteristic. e.g brown and blue eyes

Question 13

What does dominance effect in Alleles?

Answer 13

which allele will have its code read to synthesise a specific protein.

Question 14

What are most proteins controlled by?

Answer 14

2 alleles, some are dominant over others.

Question 15

what is the name of traits that can be hidden by others?

Answer 15

regressive traits

Question 16

What is a dominant allele?

Answer 16

an allele which can be observed un outward appearance of an individual (phenotype)

Question 17

What are dominant alleles always expressed in?

Answer 17

a cell’s phenotype

Question 18

How many copies of dominant allele are needed to be inherited to be expressed?

Answer 18

only one copy of the dominant allele needs to be inherited to be expressed

Question 19

what are dominant alleles represented by?

Answer 19

An uppercase letter.

Question 20

What are recessive alleles?

Answer 20

traits that are masked by the dominant allele

Question 21

How are alleles masked/hidden?

Answer 21

if only one copy is present, it is hidden or masked by the dominant allele

Question 22

How are recessive alleles represented?

Answer 22

by a lowercase letter.

Question 23

What does homozygous mean?

Answer 23

if alleles for characteristics are the same, said to be homozygous for that trait.

Question 24

What does homozygous dominant mean?

Answer 24

It means there are two dominant alleles present. e.g BB

Question 25

What does homozygous recessive mean?

Answer 25

There are two recessive alleles present. e.g bb

Question 26

What does heterozygous mean?

Answer 26

if alleles for characteristic are different, said to be heterozygous for that trait.

Question 27

what does dominant allele effect?

Answer 27

protein made and trait expressed depend on which allele is dominant. e.g pigment for brown eyes.

Question 28

What are the four types of inheritance?

Answer 28

complete dominance, co-dominance, autosomal inheritance and sex-linked inheritance.

Question 29

What is complete dominance?

Answer 29

if dominant allele is present, it will always be expressed

Question 30

What is the notation used for complete dominance?

Answer 30

One letter, and uppercase for dominant, lowercase for recessive. e.g Bb

Question 31

What is co-dominance?

Answer 31

When there is no dominant allele. The phenotype is a blend of both alleles. e,g red + white = pink

Question 32

What is notation used for co-dominance?

Answer 32

Two letters, both uppercase. e.g RR or RW

Question 33

What is autosomal inheritance?

Answer 33

When the gene is located on an autosome.
Traits can be autosomal dominant or autosomal recessive.

Question 34

What is autosomal dominance?

Answer 34

the trait/disorder is determined by the presence of a dominant allele.

Question 35

What does autosomal recessive mean?

Answer 35

The trait/disorder is determined by presence of two recessive alleles.

Question 36

What is the notation used for autosomal inheritance?

Answer 36

BB or Bb (example)

Question 37

What is sex-linked inheritance?

Answer 37

where the gene is located on the sex chromosome. It can be either X or Y, but usually X.
e.g colour blindnesss

Question 38

What traits can sex-linked inheritance bring?

Answer 38

Sex-linked dominant and sex-linked recessive.

Question 39

What does sex-linked dominant mean?

Answer 39

the trait/disorder determined by presence of dominant allele on X chromosome

Question 40

What does sex-linked recessive mean?

Answer 40

trait/disorder is determined by presence of one or two recessive alleles on X chromosome.

Question 41

What notation is used for sex-linked inheritance?

Answer 41

Females
- homozygous X^N X^N or X^n X^n
- heterozygous X^n X^N (carrier)

Males
- unaffected X^N Y
- Affected X^N Y
There is no male heterozygote.

Question 42

What does a ‘carrier’ refer to?

Answer 42

Someone who is heterozygous for a genetic disorder, but does not have it themselves.
They can pass it onto the next generation.
e.g CC = no Cystic Fibrosis
cc = SF
Cc = carrier of CF