Genetics and inheritance (educate)

Question 1

Is it possible to have the cystic fibrosis gene and not have the disorder?

Answer 1

yes
An individual must have two recessive alleles to have the disorder.

Question 2

What word means ‘having two copies of the same allele’?

Answer 2

Homozygous
AA or aa.

Question 3

Homozygous

Answer 3

a genetic condition where an individual possesses two identical alleles for a particular characteristic. For example AA or aa.

Question 4

What word means ‘having two different alleles of a gene’?

Answer 4

Heterozygous
Aa.

Question 5

Heterozygous

Answer 5

a genetic condition where an individual possesses two different alleles for a particular characteristic. For example Aa.

Question 6

What do we call a description of an individual’s alleles for a particular gene?

Answer 6

Genotype

Question 7

What do we call a description of a physical characteristic controlled by a gene?

Answer 7

phenotype

physical characteristic possessed by an individual. For example eye colour or blood group.

Question 8

What is the allele that is expressed in the heterozygous individual?

Answer 8

dominant allele
For example, in the genotype Aa, the A would be expressed.

Question 9

What part of the cell is affected by cystic fibrosis?

Answer 9

affects the cell membrane.

Cystic fibrosis affects the cell membrane by causing a faulty CFTR protein, which disrupts the movement of chloride ions. This leads to thick, sticky mucus buildup due to improper water balance across the membrane.

Question 10

Is Cystic fibrosis inherited from one parent or both?

Answer 10

Both parents
since it’s a recessive disorder so for a person to inherit Cystic fibrosis they need to inherit an affected recessive allele from both parents.

Question 11

What name is given to someone who has a gene for a recessive genetic disorder, but does not have the disorder?

Answer 11

a carrier

Question 12

Is it possible to have the polydactyly gene and not have the disorder?

Answer 12

No
It isn’t possible to have the polydactyly gene and not have the disorder because polydactyly is controlled by a dominant gene.

Question 13

Can cystic fibrosis be inherited from one parent?

Answer 13

No
since it’s controlled by a recessive allele.

Question 14

Is the cystic fibrosis allele dominant or recessive?

Answer 14

recessive
A sufferer must inherit one affected recessive allele from each parent.

Question 15

What name is given to the genetic disorder which affects mucus production in organs such as the lungs and intestines?

Answer 15

cystic fibrosis.

Question 16

If only one parent has polydactyly, is it possible that his or her children will have it?

Answer 16

Yes
because polydactyly is usually a dominant trait.

Question 17

What name is given to an allele which controls the development of a characteristic even when it is present on only one of the chromosomes?

Answer 17

A dominant allele

Question 18

What name is given to different forms of a gene?

Answer 18

An allele

Question 19

allele

Answer 19

An allele is a different form of a gene.

Question 20

what are the male and female chromosomes?

Answer 20

males have XY chromosomes

females have XX

Question 21

What name is given to the condition where a person has extra fingers and/or toes?

Answer 21

polydactyly

Question 22

polydactyly

Answer 22

when some people are born with extra fingers or toes.

Question 23

Is the polydactyly allele dominant or recessive?

Answer 23

dominant

Question 24

If William and Julie are both heterozygous for the alleles for eye colour (Bb) what is the percentage chance that their next child will be homozygous recessive?

Answer 24

William and Julie are both Bb.
Bb × Bb
Offspring: BB, Bb, Bb, bb
There is a 25% chance that their next child will be homozygous recessive bb.

Question 25

The recessive allele that leads to the development of colour blindness is carried on which of the sex chromosomes?

Answer 25

X

Question 26

Finish this sentence. An organism with two different alleles for a gene is called __________.

Answer 26

heterozygous

Question 27

Finish this sentence. An organism with two copies of the same allele for a gene is called __________.

Answer 27

homozygous

Question 28

What is the name given to the physical characteristics of an organism due to interaction between the genotype and the environment?

Answer 28

phenotype

For example, a child may inherit the genes to grow tall but will not do so unless they receive adequate food from the environment.

Question 29

What is the name given to the genetic makeup of an organism?

Answer 29

genotype.

For example AA, Aa or aa.

Question 30

A dog breeder has a brown-haired dog (Bb) and a white-haired dog (bb). If she breeds these dogs, and the mother has a litter of 8 pups, how many should have white fur?

Answer 30

Brown haired dog (Bb) × White haired dog (bb)

Possible offspring genotypes: Bb, Bb, bb, bb

Possible offspring phenotypes: Half the litter (2 out of 4 or 50%) should have brown fur (Bb)
and half (2 out of 4 or 50%) should have white fur (bb).

Question 31

A farmer crossed a yellow maize plant (Yy) with another yellow maize plant (YY). He planted 200 seeds from this cross. How many of the plants would be yellow?

Answer 31

Yellow maize plant × Yellow maize plant
Yy × YY

Offspring genotypes: YY YY Yy Yy

All 200 plants would be yellow.

Question 32

A plant has one red flower allele and one white flower allele. Its flowers are red. What word is used to describe the white flower allele?

Answer 32

recessive
If a plant with red flowers has one red flower allele and one white flower allele, the white flower allele must be recessive to the red flower allele.

Question 33

A cat has an allele for ginger fur, yet its fur is black. What word would you use to describe the allele for ginger fur?

Answer 33

recessive

If a cat has black fur yet it has an allele for ginger fur, the ginger allele is described as being the recessive allele.

Question 34

What name is given to an allele which controls the development of characteristics only if the dominant allele is not present?

Answer 34

recessive allele

An allele which controls the development of characteristics only if a dominant allele is absent is called a recessive allele.

Question 35

Jakob and Anna are brother and sister. Is their DNA likely to be identical?

Answer 35

no

Question 36

Josh and Megan both have polydactyly. Is it possible that they could have children who do not have the disorder?

Answer 36

yes
It is possible to have a child without polydactyly. If they are both heterozygous for the condition, their offspring could inherit the double recessive genetic makeup.

Question 37

Neither Andrzej nor Anna has cystic fibrosis. Is it possible that their children will have it?

Answer 37

yes

Even though neither Andrzej nor Anna has cystic fibrosis, because the condition is controlled by a recessive allele, if both parents are heterozygous for the condition they will carry the cystic fibrosis allele but not suffer form the condition themselves. If the offspring inherits a recessive gene from each parent, they will have the condition.

Question 38

True or false? Daniella has cystic fibrosis. If she has children, they will all either have the disorder or be a carrier.

Answer 38

true

If Daniella has cystic fibrosis she must be double recessive so will pass the affected allele on to her offspring.

Question 39

what is cystic fibrosis

Answer 39

It is a genetic disorder in which there is an excessive production of mucus.

damaging lungs as it blocks airways