Introduction to molecular biology Flashcards
What is the structure of DNA?
- adenine forms two hydrogen bonds with thymine
- guanine forms three hydrogen bonds with cytosine
What is the structure of the double helix?
made of a sugar-phosphate backbone with bases on the inside of the structure
How are the DNA strands arranged?
anti-parallel - each strand is of the opposite polarity with one in the 5’3’ direction and the other in the 3’5’ direction
What are the two types of repetitive DNA?
interspersed repeats
tandem repeats
What are the three types of DNA replication?
semiconservative model
conservative model
dispersive model
What happpens in a polymerase chain reaction?
- the strands are separated
- primers are bound to the strands
- new DNA synthesised
- multiple copies made
What is the function of DNA sequencing?
determines precise order of nucleotides in DNA molecule
What is electrophoresis?
used to separate pieces of DNA that differ in length by only one base
What are the uses of PCR?
genotyping
mutation detecting
paternity testing
What are the main differences between DNA and RNA?
- uracil is used in RNA and thymine in DNA
- RNA has more complex secondary and tertiary structure
- DNA only involved in information storage but RNA is a catalyst, guide, message
What is an intron?
non coding section of RNA transcript
What is an exon?
coding section of RNA transcript
What is a splice site?
a genetic mutation in the specific site at which RNA splicing takes place
What is a promoter?
the region of DNA that initiates transcription of a particular gene
What is an enhancer?
short region of DNA that can be bound with proteins to activate transcription of a gene
What is mRNA?
carries genetic info from DNA to the ribosome
What are the two domains of transcription factors?
DNA binding domain
activation domain
How does RNA splicing take place?
through two esterification reactions
What is the function of alternative RNA splicing?
allows more than one protein to be produced from a gene
What is the significance of triplets?
more than one triplet can code for the same amino acid
How is information read from DNA code?
- the starting point is the initiation codon
- the ending point is the stop codon
What are the three stages of protein translation?
initiation
elongation
termination
What are the four main types of mutations?
deletion
insertion
substitution
point
What are frameshift mutations?
affect the whole amino acid chain
What are silent mutations?
change a single letter without affecting any of the amino acids
What is a polymorphism?
minor change in DNA that is present in less than 1% of the population
What are transfer RNAs?
‘adaptor’ between the codon and the specific amino acid
What happens after translation?
- translocation to the relevant part of the protein
- protein folding
- post-translational modification
What effects can mutations in a cell have?
- no transcription
- protein incorrectly processed
- inappropriately regulated
