topic 3 - genetics Flashcards
What does meiosis form
Four daughter cells, each with half number of chromosomes and this results in genetically different haploid gametes
What is DNA as a polymer made up of
Two strands coiled to form a double helix
Strands linked by a series of complementary base pairs joined together by weak hydrogen bonds
Nucleotides that consist of a sugar and phosphate group with one of the four different bases attached to the sugar
What is the genome
The entire DNA of an organism and a gene as a section of a DNA molecule that codes for a specific protein
How is DNA extracted from fruit?
Mash some strawberries and then put them in a beaker containing the solution of detergent and salt – mix well.
The detergent will break down the cell membranes to release the DNA. The salt will make the DNA stick together.
Filter the mixture to get the froth and big, insoluble bits of salt out.
Gently add some ice cold ethanol to the filtered mixture
The DNA will start to come out of a solution as it’s not soluble in cold alcohol. It will appear as a white stringy precipitate that can be carefully fished out with a glass rod.
What are alleles?
Genesthat exist in different versions
What does homozygous mean?
If an organism has two alleles for a particular gene that are the same
What does heterozygous mean?
If it’s two alleles for a particular gene are different
What does genotype?
Combination of the alleles you have
What does phenotype?
You alleles determine what characteristics you have
What is. A chromosome
thin strands of DNA
What is a gene
Section of DNA
What is dominant allele
Always express even if there is one copy of it
What is a recessive allele
Only expressed if the individual has two copies and doesn’t have the dominant allele of that gene
What is a gamete
Reproductive cell
What is a zygote
Fertilized egg cell
Most phenotypic features of the result of what?
Multiple genes rather than single gene inheritance
Describe the causes of variation that influence phenotype
Genetic variation - caused by organisms having different alleles which can lead to differences in phenotype
This arises through mutations . Sexual reproduction also causes genetic variation since it results in alleles being combined in lots of different ways and offspring
Environmental variation – different characteristics caused by an organisms environment
What were the outcomes of the human genome project and its potential applications within medicine
It helped to identify 1800 genes related to disease
Prediction and prevention of disease diseases
- many common diseases like hunters and heart disease are caused by the interaction of different genes as well as lifestyle factors
- if doctors knew what predisposed people to what diseases, we could all get individually tailored advice on the best diet and lifestyle to avoid our likely problems
Testing and treatment for inherited disorders
- scientists are now able to identify the genes and alleles that are suspected of causing an inherited disorder and much more quickly than they do in the past
- once that causes inherited disorder has been identified, people can be tested for it and it may be possible to develop better treatment or even cure for the disease
You and better medicine
- Scientist assign new drugs that are specifically detailed to people with a particular genetic variation
- they can also determine how well an existing drug work for an individual
What are drawbacks of the medical applications in the human genome project?
Increase stress – if someone knew from an early age that their susceptible to a brain disease they could panic every time they get a headache
Geneism – people with genetic problems could become under pressure to not have children
Discrimination by employers and insurers – life insurance could become impossible to get if you have any genetic likelihood of serious disease
- employees may discriminate against people who are genetically likely to get a disease
What are the rise through genetic variation within the population of a species?
Mutations
What are genetic mutation have any effects on the phenotype?
No, not really. It’s very rare.
