From Mendel To Dna Flashcards
Why did it take a while for Medels works to be accepted?
Because at the time scientist did not know about chromosomes and genes
What did Mendel call what we would now call genes?
Factors
What sort of structure does DNA have?
A double helix structure
What is a gene?
A section on DNA
Everyone except for who has individual unique DNA?
Twins, and clones
What combination of the 23rd chromosome codes for a female?
XX
What combination of the 23rd chromosome codes for a male?
XY
What ratio or percentage is there of getting a girl or a boy?
50:50. Or 50%
What does dominant mean, in terms of genetics?
The characteristics that will show up in the offspring even if only one of the alleles is inherited
What does recessive mean?
The characteristics that will show up in the offspring only if both alleles are inherited
What is a phenotype?
Physical appearances of the characteristics e.g dimples or no dimples
What is a genotype?
The genetic make up, which alleles does the individual inherit e.g DD, Dd, dd
What does homozygous mean?
Both alleles are the same DD (homozygous dominant) or dd (homozygous recessive)
If someone is homozygous, they have two copies of the same allele
What is an allele?
Alleles are different versions of the same gene
For an organism to display a recessive gene what must the configuration of alleles be?
They must be the same , cc
What does heterozygous mean?
The two alleles are different Dd
If the allele is dominant how many alleles have to be inherited to have the genetic disorder? Give an example of a dominant genetic disorder?
One one allele has to be inherited eg polydactyl, where a baby is born with extra fingers of toes
How can polydactyly be passed on?
By one parent who has the dominant allele
If the allele is recessive how many alleles must a person inherit to have the disorder?
They must inherit 2 recessive alleles
What is cystic fibrosis caused by?
Inheriting 2 recessive alleles
What effect does cystic fibrosis have on the body?
It affects cell membranes and causes the production of thick mucus, this mucus can affect several organs such as the lungs and pancreas
What are parents who don’t actually have the symptoms of a recessive genetic disorder but have the alleles called?
Carriers
If a parent is heterozygous for polydactyly what percentage chance does a child have of inheriting the disorder?
50%
If both parents are heterozygous for cystic fibrosis what percentage does the child have of inheriting the disorder?
25%
