Topic 3 - Genetics Flashcards
Advantages of Sexual Reproduction
- Variation in offspring
- Better adapted
- Less disease
Disadvantages of Sexual Reproduction
- Time and energy to find mate
- Not all will have mates to pass alleles
Advantages of Asexual Reproduction
- Time and Energy efficient
- Quick
Disadvantages of Asexual Reproduction
- More susceptible to disease
Role of Meiosis
- To create genetically different gametes
DNA
Polymer made of:
- 2 strands to form double helix
- Strands linked by complementary base pairs
- Weak hydrogen bonds between pairs
- Nucleotides with sugar and phosphate group with 1 base attached to sugar
Genome
- Entire DNA
Gene
- Section of DNA coded for specific characteristic
Step 1 - DNA Extraction
- Mash fruit
Step 2 - DNA Extraction
- Add detergent and salt
Step 3 - DNA Extraction
- Filter
Step 4 - DNA Extraction
- Add ice cold ethanol
Genetic Variants in the NON-CODING DNA of a gene can affect phenotype by…
- changing the amount of protein produced
Genetic Variants in the CODING DNA of a gene can affect phenotype by…
- changing the amino acid sequence and therefore the protein produced
Transcription (first) phase of Protein Synthesis
- DNA unwinds
- RNA nucleotide line up along template strand using complementary base pairing to copy the code. T is replaced by U
- mRNA forms and leaves the nucleus
Translation (second) phase of Protein Synthesis
- mRNA arrives at ribosome
- tRNA brings over the corresponding anticodon
- bond form between amino acids
- The remaining amino acids fold on each other and form a protein
What did Mendel’s work help discover?
- Selective Breeding
- Alleles separate during gamete formation (Law of Segregation)
Why are there differences in the inherited characteristics as a result of alleles?
- Dominance and Recessiveness
- Multiple Alleles
- Mutation
- Environmental factors
- Random combinations during reproduction
Allele
- Version of a gene which code for different versions of a characteristic
Phenotype
- Physical observable characteristic
Genotype
- Alleles that code for phenotype
Dominant
- Allele which is always expressed in Genotype/Phenotype
Recessive
- Allele only expressed if there are 2 of them
Homozygous
- Two same alleles
Heterozygous
- Two different alleles
Chromosomes
- Structures in cells which carry DNA
Monohybrid Inheritance
- Inheritance of characteristics controlled by a single gene
Description of inheritance of the ABO blood groups with reference to multiple alleles and codominance
Multiple Alleles:
- Determined by presence of 3 alleles: IA, IB and IO
Codominance:
- IA and IB are codominant, meaning if an individual inherits both alleles, they will express IAB allele
How are sex-linked genetic disorders inherited?
Recessive disorders:
>Males
- Chromosomes X^r,Y will express disorder
>Females
- Chromosomes X^r,X^r will express disorder
Dominant disorders:
>Males
- Chromosomes X^R,Y will express disorder
>Females
- At least one X^R (X^R,X^R or X^R,X^r) will express disorder
Most phenotypic features are the result of:
multiple genes, not only 1
Causes of variation:
Genetic:
- Mutation and sexual reproduction
Environmental:
- An organisms’ environment
The Human Genome Project:
- Mapped entire human genetic code
Allows for: - Genetic disorder testing
- Personalised medication
Genetic variation in a species are due to:
mutation
Most genetic mutations have no affect on
phenotype
