genetics Flashcards
The differences in characteristics between individuals of the same speciesis known as….
Variation
What type of variation is passed on from parents to offspring, via genes during reproduction
Genetic
Variation which is the result of differences in the surroundings, or what an individual does.
Environmental
Give three examples of genetic variation
blood group, natural skin colour and natural eye colour, free or attached earlobes (there are more - check your Science booklet for examples)
Give three examples of environmental variation
Scars, tattoos, hair length (there are more - check your Science booklet for examples)
How do you know blood group is a genetic (inherited) and not environmental characteristic?
You are born with a particular blood group
It cannot change during your life
Your lifestyle does not affect your blood group
In which part of the cell is genetic information found?
Nucleus
How many pairs of chromosomes do (most) human cells contain
23
What are chromosomes made of?
DNA (a long molecule)
A short section of DNA that codes for specific features is known as what?
Gene
How do we describe the structure of DNA?
Double helix
How many versions of each gene do we have?
2
What are different versions of the same gene known as?
Alleles
A person has genotype Hh - which letter represents the dominant allele and which represents the recessive allele
H - dominant. h - recessive
In cats - H represents long hair and h short hair. Cat 1 has genotype Hh, cat 2 also has genotype Hh - what is the chance their offspring will have short hair?
25% - possible combinations are HH (long hair), Hh (long hair), hH (long hair), hh (short hair) - you can use a punnet square to work this out
