Inherited change

Question 1

How many alleles are for each gene?

Answer 1

Two alleles for each gene.

Question 2

Define Genotype.

Answer 2

All DNA makeup of an organism.

Question 3

Define Phenotype.

Answer 3

Observable characteristics of an organism. Its a result of interactions between the genotype and the environment.

Question 4

Define allele.

Answer 4

One of a number of alternate forms of a gene.

Question 5

Define Gene.

Answer 5

Section of DNA on a chromosome coding for one or more polypeptides.

Question 6

Define chromosome.

Answer 6

Thread like structure made of proteins and DNA by which hereditory information is physically passed from one generation to the next.

Question 7

Define Homologeous Chromosomes.

Answer 7

Pair of chromosomes that have the same Loci. So determine the same features. However the alleles of the genes may vary between them.

Question 8

Define Homozygous.

Answer 8

Same alleles.

Question 9

Define Heterozygous.

Answer 9

Different alleles.

Question 10

Define dominant allele.

Answer 10

An allele that is always expressed in the phenotype of an organism.

Question 11

Define Recessive allele.

Answer 11

When the effect of an allele is apparent in the phenotype of a diploid organism but only when both alleles are identical.

Question 12

Define Haploid.

Answer 12

Cells that contain only a single copy of each chromosome.

Question 13

Define Diploid.

Answer 13

Cells in which the nucleus contains two sets of chromosomes.

Question 14

Define Co-dominant alleles.

Answer 14

Both alleles for one gene in a heterozygous organism contribute to the phenotype.

Question 15

Define multiple alleles.

Answer 15

A gene that has more than two possible alleles.

Question 16

Define mutation.

Answer 16

A sudden change in the amount or the arrangement of the genetic material in the cell.

Question 17

Define Monohybrid Inheritence

Answer 17

• Study of the inheritence of a single gene.
• In the most simple cases there is a dominant and recessive allele.

Question 18

How do you assign letters to alleles in Punnete sqaures?

Answer 18

For the dominant allele have the capital letter e.g. P

For the reccesive allele assign the same letter but in the lower case e.g. p

Question 19

How do you draw genetic diagrams for monohybrid inheritance?

Answer 19

1. First draw their gametes, write the allele and their gene than draw the letter the gamete for them would have carried. E.g. Pp the gamete would be P.
2. After you have the two gametes look at them and write what dominant allele would dictate the offspring. This would be for F1 (Generation one) e.g. Pp would be all purple flower colour.
3. Then make two gametes from Pp (going with this example one gamete P and another p)
4. Lastly make a Punnete square out of them Pp in one Pp in the other collumn. TGrt the results and write the phenotype’s in their respective boxes and then write the percentages of each phenotype or genotype for the alleles. E.g. 75% Purple flower colour and 25% White flower colour.

Question 20

What do pure breeding individuals have?

Answer 20

Same alleles, so they are homozygous individuals.

Question 21

Define Dihybrid Inheritance.

Answer 21

The study of inheritance in two genes found on different chromosomes.

Question 22

How do you genetic diagrams for dihybrid inheritance.

Answer 22

1. Write the genotype’s of the parents and then write their alleles theyll pass on below.
2. Write down alleles that will be in F1
3. Draw all possible gametes from F1 that’ll be in F2
4. Draw the grid with all the gamete possabilities on the axis labels also write the dominant phenotypes in each box
5. record hw many possibilities are in the box each and then make them into a ratio to each other. E.g. Ratio: 9:3:3:1

Question 23

What is the Principle of Independant Assortment?

Answer 23

When each pair of alleles segregates independantly of the other pair’s alleles during gene formation.

Question 24

Define Autosomal chromosomes.

Answer 24

Any of the non-sex chromosomes. (not X or Y)

Question 25

What is an Autosome?

Answer 25

A non-sex chromosome.

Question 26

What does linked genes mean?

Answer 26

Genes that are found on some chromosomes.

Question 27

What is Autosomal linked inheritance?

Answer 27

Study of the inheritance of genes that are on the same non-sex chromosome.

Question 28

What is the genotype of genes as they are on the same chromosome?

Answer 28

As they are linked on the same chromosome the gametes are both e.g. Pp and Ll as they are attached on the same chromosome.

Question 29

What’s the process for working out the phenotype of the F2 generation in linked inheritance.

Answer 29

For the parents draw the gametes by drawing the genoypes linked by theor chromosome and write their phenotype underneath them.

Then work out the dominant alleles for F1 from that and draw the same thing but for F1.

Then draw a Punnet square for F1 for each allele (side on a chromosome) put them into one axis on the square with their correspondindg allele from the same chromosome on the same axis.

Di the square, wright the phenotypes below them in their square, then wright their phenotypic ratio underneath.

Question 30

Define Codominance.

Answer 30

When both alleles in a gene are expressed in the phenotype of heterozygeous individuals.

Question 31

Give an example of Codominance.

Answer 31

Flower colour in Snap Dragons.

Alleles = C means colour gene

C^R = Red flower colour

C^W = White flower colour.

C^R + C^R = Red flowers

C^W + C^W = White flowers

C^R + C^W = Pink flowers

Then do a Punnet square for them to find the phenotypic ratio.