Inheritance – What you need to know
The numbers refer to pages in ‘Leckie & Leckie Success Guide’
Variation (p74-75, 82)
G
State that a species is a group of organisms which can interbreed
and produce fertile offspring
G
State that variation can occur within a species
G
Give examples of continuous and discontinuous variation
C
Explain what is meant by continuous and discontinuous variation
What is inheritance? (p76-81)
G
State that some characteristics of an organism are determined by
genetic information received from the parents
G
State the meaning of the term phenotype and identify examples of
phenotypes of the same characteristic
G
Identify examples of true-breeding, dominant and recessive
characteristics
G
Identify generations as P, F1 and F2 in examples of crosses
C
State that the parents in experimental monohybrid crosses are
usually true-breeding and show different phenotypes of the same
characteristic
C
Predict the proportions of the phenotypes of the F2 offspring in a
mono-hybrid cross
G
State that the phenotypes of the F1 generation in a true-breeding
cross are all the same
G
State that each body cell has two matching sets of chromosomes
G
State that sex cells are called gametes
G
State that the number of chromosomes is halved during gamete
formation to a single set
G
State that each sex cell carries one set of chromosomes
G
Describe how a complete double set of chromosomes is achieved at
fertilisation
G
State that genes are parts of chromosomes
G
State that a characteristic is controlled by two forms of a gene
C
State that different forms of a gene are called alleles
G
State that each parent contributes one of the two forms
G
State that each gamete carries one of the two forms of the gene
G
State that the word genotype means the type of genes which an
organism possesses
C
Explain the effects of chance in causing differences between
predicted and observed ratios in monohybrid crosses
G
State that the sex of a child is caused by chromosomes called X
and Y
G
State that in humans, each male gamete (sperm) may have an X or a
Y chromosome while each female gamete (egg) has an X
chromosome
G
Explain how the sex of a child is determined with reference to X
and Y chromosomes
Genetics and society (p82-83)
G
Give two examples of an improved characteristic resulting from
selective breeding e.g. increased yield, increased disease
resistance or increased growth
C
Give one plant and one animal example of the improvement of a
characteristic through selective breeding
G
Describe one example of a human condition caused by a
chromosome mutation e.g. Down’s syndrome
C
Give an example of an advantageous chromosome mutation (of
economic importance to man) in a plant or animal
G
State that amniocentesis can be used to detect chromosome
abnormalities before birth
C
Give an example of a factor which can influence the rate of
mutation in an organism