Biology b1

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The sex of an individual is determined by a pair of chromosomes. Males have one X and one Y chromsome; females have a pair of X chromosomes. Explain why the sperm are said to 'decide' the sex of a baby.
Half the sperm carry an X chromosome and half the sperm carry a Y chromosome. All the eggs carry an X chromosome so which type of sperm fertilises the egg decides whether the baby is female (**) or male (XY)
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What is the meaning of genotype?
The genetic make-up of an organism.
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What is the meaning of phenotype?
The characteristics shown by an individual.
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What is the meaning of heterozygous?
When a pair of alleles for a characteristic are different.
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What is the meaning of homozygous?
When a pair of alleles for a characteristic are the same.
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Linda says every pregnancy should be tested for Huntington's disease and the fetus aborted if the condition is present. Write a response to Linda explaining why her idea is potentially unethical. (finish answer)
Hungtington's disease is an incurable genetic disorder that causes suffering. However people with the condition don't develop it until later life. It would be unethical to abort a fetus carrying the disorder as it could lead a normal life if allowed
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true postive true negative false positive false negative (do this on paper with a pen)
(insert text)
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Genetic diagram [punnett square or family tree] (do this on paper with a pen)
(insert diagram)
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How many chromosomes do human cells have?
23 pairs of chromosomes (46 in total).
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What is variation and what may it be due to?
Variation is the differences between individuals of the same species, variation may be due to genetic factors e.g. dimples and eye colour or environmental factors e.g. scars and hairstyle.
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What proteins can be formed inside a cell?
Structural proteins for cell growth or repair e.g. collagen and functional proteins e.g. enzymes to speed up chemical reactions such as amylase.
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What is meant by a carrier of a genetic disease?
Someone who could possibly pass on the disease to a child but doesn't have it themselves.
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Genetic testing can do be used to screen individuals. What does genetic testing screen individuals for?
Susceptibility to certain diseases or conditions and possible problems with certain prescribed drugs or treatments.
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Why should doctors screen babies at birth?
So the the doctors can tailor healthcare and prevent problems and to stop genetic disorder from being passes on eliminating them completely.
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What is Pre-implantation Genetic Diagnosis? (PGD)
Involves removing a cell from an embryo at an early stage of development and testing it for genetic disorders.
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What is embryo selection and list the stages of it. (finish answer)
Embryo selection is another way of preventing babies from having genetic disorders. Embryos can be produced by in vitro fertilisation (IVF). Ova are harvested from the mother and fertilised. The embryos are tested for the faulty allele. Healthy embry
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Why is embryo selection controversial?
Some people believes it's unnatural and there are concerns that people could select certain characteristics such as eye colour, sex etc. Also pre-selection of a baby's characteristics could reduce variation.
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Huntington's disease...(finish answer)
Is a genetic disorder affecting the central nervous system and it damages the brain's nerve cells. Huntington's disease causes gradual changes which develop into symptoms including involuntary movement, clumsiness, memory loss, mood changes and inab
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Cystic fibrosis...
Affects cell membranes, causing a thick, sticky mucus, especially in the lungs, gut and pancreas. Symptoms can include weight loss, difficulty in breathing, chest infections and difficulty in digesting food.
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What is a clone?
An organism genetically identical to the parent.
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Why will someone with only one allele for Huntington's disease definitely develop the disease?
Because the allele for Huntington's disease is dominant.
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Adult stem cells...
are taken from areas that are adapted for replacement and repair of tissues, such as umbilical cord and bone marrow. Adult stem cells have the potential to develop into a range of specialised cells but not all types.
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Embryonic stem cells...
are taken from a developing embryo so to produce them it's necessary to clone embryos. Embryonic stem cells have the potential to develop into any kind of specialised cell.
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Other cards in this set

Card 2

Front

What is the meaning of genotype?

Back

The genetic make-up of an organism.

Card 3

Front

What is the meaning of phenotype?

Back

Preview of the front of card 3

Card 4

Front

What is the meaning of heterozygous?

Back

Preview of the front of card 4

Card 5

Front

What is the meaning of homozygous?

Back

Preview of the front of card 5
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