B3.1 - New Technology Flashcards
How many genes are there for one characteristic?
There are two genes for the same characteristic, one inherited from the mother and one from the father.
What is meant by an allele?
An allele is a different form of the same pair of genes.
What is the difference between the dominant and recessive alleles?
Dominant alleles are always expressed in the organism while recessive alleles are only expressed when two copies are present.
This means that only one copy of the dominant allele needs to be present for the characteristic to be shown in the organism. Two recessive alleles are needed for the characteristic to be shown in the organism.
What is a Punnett square?
A Punnett square is a table which shows what happens to alleles in a genetic cross.
img: https://useruploads.socratic.org/V0oiMzSfRaCrAfg9V5wN_punnett.jpg
If the fathers alleles are ‘Bb’ and the mothers alleles are ‘bb’, what is the chance (%) that the offspring inherits the recessive characteristic?
B b
b Bb bb
b Bb bb
The chance that the offspring inherits the recessive characteristic is 50%.
This is because the recessive allele is always shown as the uncapitalized letter and that there has to be 2 copies present (‘bb’) of the recessive allele to be expressed.
What are genetic disorders?
Genetic disorders are anomalies in genes.
what is meant by a carrier of a genetic disorder?
A carrier means the person has one allele of the disorder but does not have the disorder.
If a genetic disorder is caused by a recessive allele ‘c’ then a carrier can have one recessive allele and one dominant allele but still not have the disorder. This person is a carrier.
What is meant by selective breeding?
Selective breeding, or artificial selection, is breeding specific organisms to gain specific characteristics.
What is an advantage of selective breeding?
Certain desirable characteristics can be gained in an offspring that could help a farmer.
What is a disadvantage of selective breeding?
Selective breeding can cause loss of variation within a species because every generation organisms will have more and more similar genes.
What is genetic engineering?
Genetic engineering is altering an organism’s genes to produce an organism with desirable characteristics.
Name an advantage of genetic engineering?
It is a very quick way to produce an organism with desirable characteristics compared to selective breeding.
Name a disadvantage of genetic engineering?
The release of genetically modified organisms into nature can cause spread of diseases and decrease animal welfare.
How does one organism gain a desirable characteristic through genetic engineering?
Genes from another organism (foreign genes) are taken that show the desirable characteristic and are placed into the organism that scientists want genetically modified.
What are two useful chemicals that can be produced by genetically modifying bacteria?
Vaccines and antibodies.
