Topic 3 - Reproduction & Inheritance Flashcards
Genetics
What are the advantages of sexual reproduction?
- Produces variation in offspring, decreasing the chance of extinction, as mutations contribute to survival advantage
- Allows for selective breeding, as mutations can be predicted and taken advantage of. Eg. increasing food production by breeding animals with lots of meat
What are the advantages of asexual reproduction?
- Only one parent is needed
- Uses less energy and is faster, as organisms don’t need to find a mate
- In favourable conditions, lots of identical offspring can be produced
What does meiosis involve?
- The production of 4 daughter cells
- Daughter cells have n chromosomes
- Daughter cells are non-identical, due to chromosonal crossing over
- Daughter cells are are haploid cells/gametes
Define allele
- The different forms of a gene
- Code for different forms of the same protein
What is the relationship between dominant and recessive alleles?
The recessive allele is only expressed if no dominant allele is present in that gene
What does it mean for an allele to be expressed?
It has contributed to its corresponding observable characteristic (phenotype)
What is meant by codominance
When both alleles of the genotype are expressed in the phenotype
What diagram depicts monohybrid (single gene) inheritance and what does it look at?
- Punnett Square
- It looks at the probability of offspring inheriting a certain genotype from their parents
- Uppercase letters signify a dominant allele
What does a family pedigree depict and what does it look like?
- They are used to show how a condition is passed down through generations
- Squares represent males; circles represent females
- Black shapes represent an affected individual
Name 2 genetic diseases, their causes and their symptoms
- Sickle Cell Anaemia - caused by a mutation in the haemoglobin beta (HBB) gene / the inheritance of 2 recessive HBB alleles, resulting in less haemoglobin being synthesised - causing fatigue, oxygen deficiency and delayed growth
- Cystic Fibrosis - caused by a mutation in the CFTR gene / the inheritance of 2 recessive CFTR alleles, resulting in less CFTR protein being synthesised, which damages the regulation of salt and water on internal surfaces - causing increased mucus production, recurrent chest infections, wheezing and salty tasting skin
What defines an individual’s blood group?
The type of antigens on their red blood cells
What blood group has 0 antigens on the red blood cells
O
What blood group allele is always recessive
O
What blood group is the result of codominance
AB
What do blood-related punnett squares look like?
The alleles are expressed as exponents on the letter I
