1 - Genetics Flashcards
(29 cards)
Define Variation
The presence of differences between living things of the same species.
Allele
A different version / form of the same gene.
Gene
A section of DNA that determines (e.g.) a certain characteristic, such as your hair colour, eye colour etc.
Dominant Allele
When an allele is always expressed, even if there is only one of them.
Recessive Allele
An allele that will only be expressed if inherited from both parents.
Phenotype
The physical characteristic of a specific species.
Example: Red Petals or Yellow Petals
Genotype
The allele pair for each characteristic.
Homozygous
When the alleles in a matching pair are the same.
“Homo” = Same
Heterozygous
When the alleles in a matching pair are different.
“Hetero” = Different
Punnett Square
Shows the possible combinations of alleles inherited from parents.
What sex chromosomes are associated to a Male and a Female?
XX / (46XX)= Female
XY / (46XY)= Male
What are the mains involved in Selective Breeding?
Part A
1) Choose parents with desirable characteristics, which are important enough to select.
2) Allow them to breed together.
What are the main steps involved in Selective Breeding?
Part B
3) Choose the best offspring which also show the desirable characteristics.
4) Breed them again, which is then repeated over many generations.
What are some Ethical concerns to Selective Breeding?
- Increase in inherited disorders.
- Violates animal’s rights in a way, where they are treated as human property.
What are some Welfare concerns to Selective Breeding?
- More susceptible to diseases.
- Can cause unnatural birth in some cases!
- Mortality rate can increase in the species, being affected by conditions such as Arthritis.
- Reduces the gene pool, therefore reducing variation in the species.
What is Cloning?
Where an identical genetic copy of the parent plant / animal is created.
What is Asexual Reproduction?
When there is only one parent needed (without any gametes) to produce offspring.
As a result, there is no mixing of genetic material, so the offsprings are clones.
What are some Examples of Asexual Reproduction?
- Potato Plants
- Strawberry Plants
- Daffodils
What are the steps involved in cloning a plant from a Plant Tissue Culture?
1) Tissue sample scraped from parent plant.
2) Sample is places in an agar growth medium, containing Nutrients and hormones.
3) Sample develops into tiny plantlets.
4) Plantlets placed into compost, growing to their full size and repeating the cycle.
What are the main steps involved in Cloning Animals?
Part A
1) Any body cell taken from Sheep A.
2) Egg cell taken from Sheep B.
3) Nucleus from Sheep B is isolated and inserted into isolated egg cell of Sheep A.
What are the main steps involved in Cloning Animals?
4) Newly-formed embryo is administered an electrical shock to encourage it to divide.
5) Embryo is implanted into a surrogate mother sheep / Sheep C.
6) Embryo grows into a lamb “clone” of Sheep A.
Characteristics
The features of an organism.
Gene Pool
The variety of genes available in a population.
Who was Dolly the Sheep?
An example of cloning, being the first mammal to be cloned from an adult cell.
