[W1] Intro To Module Flashcards
(28 cards)
What does classical genetics study?
Inheritance of traits from one generation to the next.
What does molecular genetics study?
Structure and function of DNA, RNA, chromatin, chromosomes, and genes at the molecular level.
What is the structural form of DNA?
The B-form, a double helix of antiparallel polynucleotide chains.
How do bases pair in DNA?
A-T and G-C by hydrogen bonding.
What is the diameter of the DNA double helix?
20 Å.
How many base pairs per turn in B-form DNA?
10 base pairs (10.4 in solution).
What grooves are present in DNA?
Major (wide) and minor (narrow) grooves.
What is a nucleoside?
A base linked to the 1ʹ carbon of a pentose sugar.
What sugar is found in DNA vs RNA?
DNA: deoxyribose (2ʹ–H); RNA: ribose (2ʹ–OH).
What is a nucleotide?
A nucleoside plus one or more phosphate groups.
How are nucleotides linked in a chain?
Via phosphodiester bonds between the 3ʹ and 5ʹ carbons of adjacent sugars.
Which bases are found in DNA and RNA?
DNA: A, G, C, T; RNA: A, G, C, U.
What are the components of a nucleotide?
A base, a sugar, and one or more phosphate groups.
What does the one gene–one enzyme hypothesis state?
A gene encodes one or more isoforms of a single polypeptide chain.
Do all genes encode polypeptides?
No, some encode structural or regulatory RNAs.
Are most coding-sequence mutations dominant or recessive?
Recessive.
What is the structure of the genetic code?
Triplet codons that are nonoverlapping.
What type of mutation shifts the reading frame?
Frameshift mutations from insertions or deletions of bases not in multiples of three.
What happens if three bases are inserted or deleted?
Adds or removes an amino acid without shifting the reading frame.
Which end is the 5’ end of a DNA strand?
The top.
Where is the 3’ OH group located?
On the 3rd carbon of the sugar.
What connects the nucleotides?
Phosphodiester linkages.
Is RNA single-stranded?
Yes, but it is highly structured.
What is an example of complex RNA structure?
Transfer RNA (tRNA).
