What is DNA?
A polymer made up of two strands creating a double helix which is contained in chromosomes
What is a gene?
A small section of DNA on a chromosome that codes for a protein
What is an allele
Different versions of the same gene
What is a genome?
The entire genetic material of an organism
Why is it important to understand the human genome?
- to search for genes linked to different types of disease
- to understand and treat inherited disorders
- to track past human migration patterns
How many chromosomes are in an ordinary body cell? How many of these determine sex?
23, 1
What is a chromosome?
The strings of DNA
What is polydactyl and what is it caused by?
Extra fingers or toes
Dominant allele
What is cystic fibrosis and what is it caused by?
A disorder of cell membrane - extra mucus,
A recessive allele
What is a genotype?
The combination of alleles
What is a phenotype?
The physical characteristic caused by the alleles
What is a carrier?
A person who has at least one allele for a disease but doesn’t suffer (unless specified in question)
What is a single gene disorder?
A disorder caused by a mutation in one single gene
What is amniocentesis?
Embryo screening during a normal pregnancy- take amniotic fluid and test for cell disorders
What is embryo screening?
Removing a couple cells from an embryo and testing them for genetic mutations / defective alleles
What are the ethical, social and economic concerns with embryonic screening?
Ethical
- ‘designer babies’/ selective breeding
- prevents emotional trauma from losing a child ad prevents a child from suffering
Social
- suggest disabled lives are inferior
- social inequality as rich people can pay for embryonic screening
Economic
- disabled children cost more for healthcare
- burden on social services
What are two reasons why sexual reproduction causes variation in the offspring?
- gametes are not identical
- genetic information is from two different parents
What are the edvantages of embryo screening?
- can find out if the embryo has an inherited disorder
- allows parents to prepare for a baby with a disorder
- allows parents to decide to continue with pregnancy
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Biodiversity35
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DNA + Inheritance18
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Food Tests6
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Enzymes8
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Digestive System10
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Diffusion, Osmosis, Active Transport11
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Hormones17
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Drug Development + Antibiotic Resistance10
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Communicable Disease19
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Photosynthesis + Respiration7
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Non Communicable Disease + Cancer + Diabetes10
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The Heart + CHD + Gas Exchange23
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Nervous System3
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Respiration10
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Cell Division + Bianry Fission10
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Evolution + Speciation19
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Plants, Tissues + Microscopy24
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Calculations + Practicals5
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Ecology+ Variation14
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Water And Ecosystems3
