10: Introduction to Genetics Flashcards
1
Q
Gregor Mendel’s 3 Laws: Law of Dominance
A
Some alleles are dominant and cover up recessive alleles
2
Q
Gregor Mendel’s 3 Laws: Law of Segregation
A
An organism has two alleles for each gene, but they can only pass on one
3
Q
Gregor Mendel’s 3 Laws: Law of Independent Assortment
A
Genes found on separate chromosomes are inherited independently of each other
4
Q
Alleles
A
- Different versions of the same gene
- Inherit one from each parent
5
Q
Diploid
A
- Most cells
- Two copies of each chromosome
6
Q
Haploid
A
- Gametes
- Only one copy of each chromosome
7
Q
Genetic Recombination
A
- Creates different combinations of genetic information from parents
- Crossing over during meiosis
8
Q
Causes of Mutation: Spontaneous
A
Incorrect DNA replication mechanism
9
Q
Causes of Mutation: Induced
A
- UV and ionising radiation
- Carcinogens e.g. chemicals, cigarettes
- Viruses
- Free radicals
10
Q
Chromosomal Mutation: Translocation
A
- Movement of DNA segments - transposition
- Cut and paste
11
Q
Chromosomal Mutation: Aneuploidy
A
- Incorrect numbers of chromosomes in cells
- Monosomy or trisomy
- Most commonly caused by nondisjunction during meiosis
12
Q
Down Syndrome Characteristics (TRISOMY)
A
- Characteristically short
- Round heads/flat faces
- Furrowed tongue causing permanent partially opened mouth
- Retarded physical, mental and psychomotor skills
- Prone to respiratory disease
13
Q
Turner Syndrome Characteristics (MONOSOMY)
A
- Female appearance but unusually short – less than 5 ft
- Female sex organs but only partially developed ovaries – usually sterile
- Skin flaps evident on the back of the neck
- Broad chest and underdeveloped breasts
- Lymphedema
- Cubitus valgus
14
Q
Consanguinity
A
- Mating with close relative AKA inbreeding
- Increases the probability of inheriting recessive disorders – relatives share similar alleles
- Non-relative is unlikely to have the recessive allele
