Genetics Flashcards
What are generative cells
Cells in gonads which give rise to games by means of meiosis
What is a locus
Position of a gene on a chromosome
What is biotechnology
The use of biological processes / organisms / systems to manufacture products intended to improve human life quality
What is Monohybrid and Dihybrid
Including only one characteristic at a time
Including two characteristic at a time
What is a dominant and recessive gene
An allele that express its phenotypic effect even when heterozygous with a recessive allele
An allele whose phenotypic effect is not expressed a heterozygote
What are menders 3 laws
1) Each characteristic is controlled by 2 genes. When gametes are formed the two genes separate so that each game contains 1 allele
- Law of Segregation
2) Various genes are separate entities and do not influence each other in any way. During gamete production, different alleles seperate independently of each other
- Law of independent assortment
3) One factor in a pair of traits masks the other trait and will be expressed while the other factor is not expressed
Explain blood grouping and paternity testing fully
1) The b-grp of the mother, cild and possible father can be determined
2) If the b-grp of the mother and possible father cannot lead to the b-grp of the child the man isn’t the father
3) If the b-grp of the mother and possible father can lead to the Childs b-grp the man might be the father
4) This isn’t conclusive as many men have the same blood group
What is a mutation
A change in the DNA sequence or the sequence of nucleotides
What causes mutations and what are the effects
- UV radiation; X-Rays; Pesticides; Viruses
- Neutral = no effect on life of organism
-Harmful = can lead to organism death
-Beneficial = contributes to genetic variation in a population by resulting in new genotypes causing changes in the phenotypes which in turn can lead to natural selection ultimately being about evolutionary change
When does a mutation take place
Crossing over
Dna replication
Transcription
Anaphase 1 and 2 ( trisomy 21)
Explain gene mutations fully
- Usually involves single gene only
- Occurs during transcription of protein synthesis
( includes point and frameshift mutations)
eg. haemophilia; albinism and colour blindness
Explain chromosome mutations fully
- Involves whole or parts of chromosomes being duplicated / missing / inverted or breaking off to join other chromosomes
- Occurs during meiosis
eg. down syndrome
Explain haemophilia; colour blindness; albinism and down syndrome fully
1) Absence of blood clotting factors
2) Due to absence of proteins that Mae either red or green photoreceptors in the eye
3) Absence of protein that makes the melanin pigment
- susceptible to skin cancer and photosensitivity
4) Due to an extra copy of chromosome 21 as a result of non-disjunction during meiosis
Why would a couple get genetic counselling
1) To determine chances of having a child with the disorder
2) To determine if wife is carrier of disorder
3) Help them decide whether they would cope with such a child
4) Help them make an informed decision on whether to have children
What is genetic engineering
- Altering the DNA of an organism using biotechnology
- Uses biotechnology to satisfy human needs
