Week 4/5 Flashcards
Define karyotype?
An electromicrograph of cells that provides information about a developing foetus. This electromicrograph is cut up and arranged in homologous pairs (size order).
Define down syndrome?
A common disorder affecting one in 600 births particularly the firstborn children of mothers over 40.
Children with Down syndrome have an extra chromosome in their cells (47 instead of 46)
Define klinefelter’s syndrome?
A disorder affecting one in 500 males.
These people carry three sex chromosomes, (XXY instead of XY) and have severe acne and an awkward build.
They do not achieve sexual maturity without hormone treatment.
Even with treatment they remain sterile.
Define turner’s syndrome?
A disorder affecting one in 2500 females. They only have one sex chromosome (XO) and have 45 chromosomes in each cell.
They fail to achieve sexual maturity without hormone treatment and are sterile because they don’t develop ovaries.
Define ‘super’ males?
A condition affecting one in 3300 males.
They have XXY chromosomes and appear normal but are taller than average and tend to be less intelligent and more prone to aggressive behaviour.
Define ‘super’ females?
A condition occurring in one in 800 females.
They have an XXX chromosome, are sexually undeveloped and are sterile.
How does genetic modification work?
Genetic information is changed by inserting new genes.
These genes are copied to all the daughter cells when the parent cell divides by mitosis.
The cells mature into a completely new strain of plant.
What can be added to plants when using genetic modification?
Insect resistance and increased nutrient value.
What is canola?
A crop that produces edible oil.
What did WA, VIC and NSW allow farmers to grow?
Genetically Modified canola resistant to herbicides commonly used to control weeds.
What does GM canola allow?
It allows farmers to spray herbicide on the crop, killing the weeds but leaving the canola unaffected.
What is white rice lacking?
Essential minerals and vitamins including vitamin A.
What does vitamin A deficiency cause?
Childhood blindness that affects up to 500,000 children worldwide.
Golden rice is genetically modified using what?
Genes from daffodils, corn and bacteria.
What does golden rice contain?
Beta-carotene, the chemical that gives carrots their orange colour, and which the body converts into vitamin A.
How much of the recommended dietary allowance of vitamin A would 225 grams of cooked golden rice provide?
50-60%
Why was golden rice developed?
To help people in developing countries where blindness due to vitamin A deficiency is a problem.
Why is GM rice not used for human consumption?
There has been a significant opposition from environmental and anti-globalisation groups to the commercial production of GM rice so its only grown for research.
Define plasmids?
Separate rings of DNA.
Define gene splicing?
When scientists cut plasmids open and splice (insert) desirable genes into the plasmid using enzymes.
Define recombinant DNA technology?
The technology of combining DNA from different genes.
What has recombinant DNA technology been used for?
Splicing the human gene that codes for insulin production into bacteria.
What has recombinant DNA technology been to produce?
Large quantities of human insulin for use by people with diabetes.
Define genome?
The genetic information carried by a haploid set of chromosomes.
What is the Human Genome Project?
An international project that aimed to:
• identify all 20,000-25,000 genes in the human genome
• determine the sequence of the 3 billion base pairs that make up human chromosomes
What percentage do humans share of their DNA?
99.9%
Define single nucleotide polymorphism (SNPs)?
Locations that differ by only one base from one human to another.
What common diseases may single nucleotide polymorphism (SNPs) be associated with?
Cardiovascular disease, diabetes, arthritis and cancer.
What must be known about a gene to make gene testing for it useful?
The function of a gene.
How many diseases have genetic tests available for them?
Over 400
Why do people get genetic tests to see if they are carriers of diseases such as Cystic Fibrosis?
Knowledge of their genetic makeup can allow people to make decisions about weather or not to have children as they may pass on a disease.
Which conditions do mothers get foetuses tested for?
Down syndrome, Turner’s syndrome and a Fragile X syndrome.
Other uses for Gene/DNA testing?
Identification of a suspect in a crime investigation
Identification of the biological parents of a child
Analysis of the DNA of both the donor and the recipient (tissue typing) in cases of bone marrow or organ transplants
Define gene therapy?
When the defective gene is replaced with a normal gene providing a potential to cure genetic diseases.
Describe how researchers think genetics can be used to treat cancer?
They discovered a gene that can be switched off, reversing the growth of blood vessels in tumours and making the blood vessels more normal in size.
Define genotype?
The actual genetic information carried by the individual.
Define phenotype?
The observable characteristics of the individual.
Define sex-linked genes?
Genes found on the X chromosome and not on the Y chromosome.
