KS3 GENETICS Flashcards
(36 cards)
How is DNA arranged in the nuclei of the cell?
Into strands called chromosomes
Where is DNA found in the cell?
DNA is found in the nucleus, it is arranged as chromosomes.
What is a ‘gene’.
A gene is a section of a chromosome that code for a certain characteristic e.g. eye colour.
What is an ‘allele’
An allele is an alternate form of a gene. E.g. if gene is hair colour, the allele may be brown hair, blonde hair, ginger hair.
List three characteristics that are genetically controlled:
- Eye colour
- Hair colour
- Blood type
List three characteristics that are environmentally controlled:
- Your language
- Fashion style
- Ability to swim
Name three characteristics that are controlled by genetic an environmental factors:
- Your personality
- Your weight
- Your intelligence
What is a dominant allele?
A dominant allele is ALWAYS expressed even if only one copy is present.
What is a recessive allele?
A recessive allele is ONLY present if two copies of the allele are present.
What is a homozygous allele?
If an organism has two copies of the SAME allele, e.g. AA or aa, it is homozygous for that trait.
What is a heterozygous allele?
If an organism has two copies of DIFFERENT alleles, e.g. Aa, it is heterozygous for that trait.
What is a genetically inherited disorder?
A genetically inherited disorder is a disorder caused by abnormal DNA from a parent.
How is a genetically inherited disorder inherited?
A genetically inherited disorder is passed from parents to offspring through the transmission of mutated genes.
What is selective breeding?
Selective breeding is when humans choose which parents to breed together. These parents will have certain desirable characteristics and are likely to produce offspring with the same desirable characteristics.
List three advantages of selectively breeding animals:
- Increased yield of food
- New varieties of crops can be produced
- Disease resistance in food crops and garden plants
List three disadvantages of selectively breeding animals:
- Smaller gene pool, more likely to pass down harmful recessive alleles
- Can lead to inbreeding
- More susceptible to diseases
List the stages for selective breeding:
1) Choose two parents with the desired characteristics
2) Breed them together
3) Choose offspring with the desired characteristic and breed them
4) Repeat this over many generations
What is genetic engineering?
Changing the genes of another organism by introducing the gene from another organism to give it a desired trait/characteristic.
What does ‘GMO’ stand for?
Genetically modified organism
What is the process of genetically engineering an organism to produce a product?
1) Select the desired characteristic (e.g. insulin gene)
2) Isolate the gene using enzymes
3) Insert the gene into another organism (e.g. bacterium)
4) Let the organism replicate and produce the product
List three advantages of genetically producing organisms:
1) Can extend the shelf life of products
2) Can increase resistance to pesticides
3) Increases crop yeild
List three disadvantages of genetically producing organisms:
- Inserted genes may have unwanted side effects.
- Possible harm when crops are eaten by humans/other animals.
- Damage to food chains.
What is cloning?
Cloning is making a genetically identical copy of an individual.
What are the two types of cloning?
Natural and artificial cloning
