DNA and Inheritance Flashcards
Where is DNA found?
In the nucleus of a cell within chromosomes
What is the purpose of DNA?
It contains the code to make proteins
What are the units of a protein called?
Amino acids
Describe the structure of DNA
2 long chains of alternating sugars and phosphates joined by pairs of bases
Ladder-like structure with the bases forming the rungs
What is the name given to the shape of a DNA molecule?
double helix
What are the 4 DNA bases?
Adenine, Thymine, Guanine, Cytosine
What is meant by complementary base pairing?
A pairs with T
C pairs with G
Why is the order of bases important?
It determines the order in which different amino acids are linked together to form different proteins
What is the triplet code (codon)?
Three consecutive bases which code for a particular amino acid
What is a genetic profile?
A unique banding pattern formed by the cutting of DNA into fragments, which are separated into bands
How are genetic profiles used?
To show the similarity between the banding patterns in two DNA samples in:
Criminal cases
Paternity cases
Classification of species
What are the potential problems when using genetic profiling for identifying genes associated with particular diseases?
- Severity of disease not known
- Undue stress if disease doesn’t develop
- Information may be passed to insurance
companies - Employment discrimination
How are genetic profiles compared in criminal cases?
If the banding patterns are IDENTICAL then the suspect is guilty!
How is paternity determined when comparing genetic profiles?
Half of the child’s bands will match those from the mother, the other half will match those from the father
What is a gene?
A section of a DNA molecule that codes for a protein
The protein determines an inherited characteristic
What is an allele?
A version of a gene that comes in a pair
What is a genotype?
The combination of alleles for a particular characteristic
What does homozygous mean?
The alleles are the same in the genotype
What does heterozygous mean?
2 different alleles in the genotype: one dominant and one recessive
What is a phenotype?
The physical characteristic determined by the genotype
Which sex chromosomes do males have?
XY
Which sex chromosomes do females have?
XX
What is cystic fibrosis?
A recessive genetic disorder which leads to a build up of mucus in the bronchioles
What does a recessive genetic disorder mean?
The mutation causing the disease is on the recessive allele
Both alleles must be recessive to inherit the disease
