Interactive Resources for Schools
This topic takes on average 55 minutes to read.
There are a number of interactive features in this resource:
Biology
PSHE / Citizenship studies
Science (applied)
Biology
PSHE / Citizenship studies
Biology
PSHE / Citizenship studies
Science (applied)
Biology
Biology
Genetics is the study of inheritanceinheritance
The transfer of characteristics from parents to children through their genes.
, that is, how characteristics are passed from one generation to the next. Gametegamete
The sex cells (ova and sperm) that join together to form a new unique diploid cell in sexual reproduction.
s are haploidhaploid
Have a single set of chromosomes.
with only one of each chromosomechromosome
A chromosome is like a packet of coiled up DNA. Humans have 23 pairs of chromosomes. They are in the nucleus of every human cell.
and therefore one of each gene. When two gametes fuse at fertilisation the zygotezygote
A fertilised cell produced as the result of the combination of an ovum and a sperm.
now has two of each gene (that is a pair of alleles for each gene) one from the mother and one from the father. Where the alleles are different, one may be recessive and the other dominant and the dominant allele will determine the characteristic.
We can use genetic diagramgenetic diagram
A diagram to represent the alleles and gametes present for a particular characteristic in parents and the possible allele combinations in their children.
s to show how a characteristic is passed on. Letters are used to represent the genes and a capital letter means an allele is dominant, and a small letter means a recessive allele.
The ability to roll the tongue is something an individual can or cannot do and is passed on genetically. It cannot be learned. In the diagram below, the parents are heterozygousheterozygous
The description of an individual who has two different alleles for one particular gene.
for tongue rolling, that means they both have one copy of the allele that allows for tongue rolling, and one that does not. Make use of the animation to understand how alleles segregate and all the possible combinations, and their frequencies.
Note: in the animation below, dragged boxes will only stay in place when you have chosen the correct place for them. If another student wanted to do the exercise, or redo it, click on "Try again" button.
Another example of trait that is genetically inherited and which inheritanceinheritance
The transfer of characteristics from parents to children through their genes.
is well understood is blood groups. The inheritance of blood group can be represented by the simplified diagram below. It shows the possible blood groups of offspring when the parents are heterozygousheterozygous
The description of an individual who has two different alleles for one particular gene.
A and heterozygous B.
The animation below shows an alternative way of illustrating the inheritance of a trait, as opposed to the tabular format used for the inheritance of tongue rolling.