Variation and Genetics Flashcards
What do genes control
Characteristics
What are versions of genes called?
Alleles
If both the alleles have the same for a particular gene, what is this called?
Homozygous
If both the alleles are different for a particular gene, what is this called?
Hetrozygous
If the 2 alleles for a particular gene are the same (Aa), which one determines the characteristic developed?
The dominant one (Capital letter)
For an organism to express its recessive characteristic, what must be true about both alleles?
They must both be recessive (aa)
For an organism to express its dominant characteristic, what must be true about both alleles?
There must be at least 1 dominant allele, but could be true (Aa or AA)
What is your genotype?
Which alleles you have
What is your phenotype?
Which characteristics you have
What are the 2 types of variation?
Genetic and environmental
What causes genetic variation?
Different genes
What is an organism’s characteristics determined by?
The genes inherited from their parents
What are characteristics of an organism influenced by?
The environment e.g hot or cold
What is a chromosome?
A long strand of DNA
What is a gene?
A section of DNA
What does a gene do?
Codes for a particular combination of amino acids which make a specific protein
How many amino acids are used in a gene?
20
What are the 4 bases?
A T C G
What does the order of bases in a gene determine?
The order of amino acids in that protein
What chromosomes do men have?
XY
What chromosomes do women have?
XX
What is your genotype?
Which alleles you have
What is your phenotype?
Which genes you have
What is cystic fibrosis caused by?
Recessive allele
What is cystic fibrosis?
A genetic disorder of the cell membranes. A lot of mucus is produced in air passages and pancreas
What is polydactyly caused by?
Dominant allele
What is polydactyly?
When someone is born with extra fingers or toes
What is sickle-cell anaemia caused by?
Recessive allele
What is sickle-cell anaemia?
When RBCs get stuck in capillaries which deprives the body of oxygen
How does embryonic screening work?
DNA is isolated, then a gene probe is labelled and is put into the DNA mix and will bind to a specific allele. When a UV lamp is shone, the probe can be seen.
When doing embryonic screening, how do you know if the genetic disorder is present?
The probe will have stuck
What is a genetic probe?
A short section of DNA which will bind to the allele for the disorder
What are some reasons for embryonic screening?
Stop suffering
Treating disorders costs the Gov a lot of money
Laws stop it from going too far
What are some reasons against embryonic screening?
Implies people with genetic problems are undesirable
Expensive
May come a point where everyone will want “designer babies”
What is sexual reproduction?
The fusion of a male and female gamete. Because there are 2 parents, the offspring contains a mixture of their parents genes
What is asexual reproduction?
No fusion of gametes or mixing of chromosomes -> No genetic variation. The offspring are clones
Name some examples of organisms which reproduce asexually
Plants, bacteria and some animals
Describe the process for adult cell cloning
Taking an unfertilised egg cell and removing the nucleus. A diploid cell from another adult body is inserted into the egg cell. An electric shock then causes the cell to undergo division. Then implanted into a surrogate mother
What are some disadvantages to cloning?
If a disease comes around, whole population is dead
Study into age-related disorders
Some people worry humans may be cloned
What do the enzymes do in GE?
Cut and paste genes
Describe the process of GE and producing insulin
Insulin gene gut out and put into a plasmid. The bacteria then reproduce like crazy
What are some disadvantages to GM crops?
Affect biodiversity, unsure whether it is safe, transplanted genes may get out into the natural environment
What are some advantages to GM crops?
Increase yield of the crop
GM crops could be engineered to give nutrients which people lack
Already being grown with no problems
