DNA 1 - MT2 - Part 1 Flashcards
What are DNA markers?
They are specific DNA sequences that can be used to identify individual people or characterize human populations
What are DNA markers used for? (3)
- Identify individual people
- Characterize human populations
- Identify and study non human species
What does the sequence of DNA refer to?
The order of DNA bases
- pairing is specific
What does Adenine base bind to?
Thymine
What does Guanine base bind to?
Cytosine
What are A, G, T and C known as?
Nucleic acids
What is DNA’s structure?
A double helix
Is DNA inherited?
Yes
- it gets passed on from generation to generation with high stability
When does DNA change?
When it gets mutated
- occurs rarely
What does DNA left at a crime scene imply?
The presence of a specific person at the crime scene
What is an example of a type of DNA left at the crime scene?
DNA fingerprints
How can DNA be used? (5)
- In a criminal case
- In determining parentage
- Use of DNA markers in tracking migrations of people
- In determining ancestry
- Markers and disease susceptibility
What can blood types be used for?
Determine parentage
- but not prove it (only can help)
How does a DNA marker track migrations of people?
The marker might spread through a human group after it has branched off from other human groups
- looking for specific characteristics in certain human groups
How does a DNA marker detect disease susceptibility?
The DNA marker can be within or close to disease genes and can signal the presence of those disease genes in someones genome
Polymer
A large molecule built from many smaller units (monomers) of a similar form
What is an example of a polymer?
DNA
What are monomers of DNA called?
nucleotides
What makes up a nucleotide? (3)
- Phosphate groups
- A sugar
- Nitrogenous bases
What is DNA strands orientation?
5’–>3’ and 3’–> 5’
- anti parallel
- has polarity
What does 5’ refer to?
How the carbons are numbered in one of the sugars
Is there polarity between the base sequences?
No
What 2 nucleic acids consists in a purine?
- A
2. G
What 2 nucleic acids consists in a pyrimidine?
- C
2. T
What order are strands made in?
5’ to 3’ direction
What happens if there are some miss pairings in the DNA strand?
It can de-stabilize it
- could possible fall apart
What type of bond are between the base pairs?
H bonding
H bonding (3)
- Weak bonds between bases
- Form and break very easily
- Easily disrupted
Why are DNA strands complementary?
Because of the base pairing
What shape is the most stable conformation and why? (2)
- Helical shape
2. Because it is in its lowest energy
DNA denaturing
Is when the DNA strands are heated up and they start to unwind and the bonds holding them together are no longer there and the strands separate
- once cooled they can re-form
- but you need a collision to do this
Polyelectrolyte theory of a gene
Says that the negative charges on the two backbones of the DNA molecule spread it out, giving easier access to the machinery that reads and copies the base sequence
What does the negative charge do on the DNA strands?
Repels each other
What groups have the negative charge?
Phosphate groups
