2.4 Variation and inheritance

Question 1

i can identify the source of an individuals unique genetic code

Answer 1

the original source of an individual genetic code is the gametes form of their parent cell. Each gamete carries a unique haploid set of genetic information from the parent. When the gametes fuse during fertilisation a new unique diploid genetic combination is formed

Question 2

chemical that chromosomes are made of

Answer 2

DNA

Question 3

where are genes located

Answer 3

genes are located on the chromosomes

Question 4

i can explain the purpose of instructions carried in a DNA code

Answer 4

The DNA code carries the instructions for the production of proteins

Question 5

the term used to describe the section of a chromosome that carries the genetic code for one protein

Answer 5

A section of DNA code carried on a chromosome is called a gene. Each gene carries the instructions for the production of one particular protein molecule

Question 6

link between an individuals genetic code and features of an organism

Answer 6

the features of an organism are determined by the proteins that it makes and the proteins that an organisms makes is determined by their genetic code. therefore the feature of an organism are controlled by their genetic code

Question 7

discrete variation

Answer 7

differences between organisms that fall into distinct groups. These characteristics are features that are controlled by a single gene (monogenic)

Question 8

continuous variation

Answer 8

differences that occur across a range of values between a maximum and a minimum. These characteristics are features that are controlled by more than one gene known as polygenic inheritance

Question 9

examples of discrete

Answer 9

long and short hair in cats
dry and wet earwax in humans
blood groups

Question 10

examples of continuous variations

Answer 10

height in humans
leaf length in plants

Question 11

allele

Answer 11

different forms of the same gene
e.g gene for hair length in cats has two alleles one for short and one for long hair. Each allele is represented by different forms of the same letter r.g A and a

Question 12

dominant

Answer 12

a dominant allele is represented by a capital letter in the genotype e.g A and it will always be expressed in a phenotype organism

Question 13

reseesive

Answer 13

a recessive allele is represented by the lower case letter in a genotype eg a and this will only be expressed as a phenotype of the organism if both alleles in the genotype are recessive

Question 14

genotype

Answer 14

this is how the two alleles of a particular gene carried by an organism are represented using letters

Question 15

phenotype

Answer 15

this is the expression of an organism genotype ie how it apears behaves the phenotype can be either dominant or reseesive

Question 16

homozygous

Answer 16

this is the genotype where both alleles are the same AA ee described as true breeding as there is only one allele they can pass on to their off spring

Question 17

heterozygous

Answer 17

genotype where two alleles are different eg Aw non true breading because they can pass on either allele to their offspring

Question 18

P F1 F2

Answer 18

P- parent
f1- first generation
f2 second generation