Science - Genetics Unit Flashcards
Define Discontinuous variation
A feature that cannot be measured and forms distinct options e.g eye color.
Define Continuous Variation
A feature that can be measured and given a value that falls into a range e.g. height.
Define Variation
The differences between organisms
Define Environmental Variation
Differences in organisms that are caused by its surroundings.
Define Physical environmental factor
A non-living factor that affects an organism e.g. weather.
Give an example for continuous variation and discontinuous variation and environmental variation.
Continuous variation: height, weight, hand span, chin shape.
Discontinuous variation: Hair color, blood groups
Environmental variation: Piercings, Streaked hair, Scars
Define Inherited Variation
inherited characteristics from parents.
How are characteristics passed on?
New-born baby’s characteristics are passed in the genes it has inherited from its parents.
How do sets of genes work?
One chromosome of each pair comes form our mother and the other chromosome in each pair comes from our father.
What is an Allele?
one member of a pair of different forms of a gene.
How do we inherit chromosomes?
Egg and sperm cells are the only cells in the body to contain 23 chromosomes – they only have one copy of each pair. During fertilisation, these cells join together to form an embryo. This means that inside each cell of the embryo there are 46 chromosomes.
Define DNA
Thread like strands in the nucleus of the cell; they contain the instructions for a living thing.
Define Gene
A length of DNA that contains 1 inherited characteristic of an organism.
Define Chromosome
A large molecule that contains genes. It is the material that transfers genetic characteristics in all life’s forms.
Define Allele
Different forms of a gene.
Compare Inherited and Environmental variation
- Inherited variation: Caused by genes passed down from our parents e.g. eye colour.
- Environmental variation: Caused by the conditions we live in e.g. abundance of food.
List these into Genetic, Environmental or both variations.
- Skin colour
- Spoken language
- Strength
- Hair length
- Eye colour
- Ear size/shape
- Height
- Hair colour
- Weight
- Tongue roller
- Genetic:
Eye colour
Ear size/shape
Height
Tongue roller - Environmental:
Spoken language - Both:
Skin colour
Strength
Hair length
Hair colour
Weight
What is Selective Breeding?
Pedigree animals (and plants) that show favourable traits are often interbred with close family members to preserve and heighten the required trait
What do you know about DNA Structure
If you unravel DNA, it looks like a twisted ladder; this is called a double helix. The building blocks of DNA are called nucleotide bases; and there are 4 of them.
How are the ATCG paired in DNA?
A is ALWAYS paired with T
C is ALWAYS paired with G
Explain the Genetic Code
Genes use a code based on group of 3 bases. These groups of 3 are called “codons” or triplets. There are 64 different codons, and they produce 20 different amino acids. Amino acids are the raw material proteins are made from.
Answer true or false:
A gene is a length of DNA
Identical twins have the same genes
Tongue rolling is NOT genetic
Genes contain chromosomes
There are 23 chromosomes in a gene
There are 46 genes in a living cell
Genes are passed on through blood
Half of your genes come from your male parent, half from your female parent
A strong gene is called recessive
Everyone has a DNA fingerprint which can be used to identify people
What you look like and how you work is all down to your genes
- T
- T
- F
- F
- F
- F
- F
- T
- F
- F
- T
- F
