Nucleic Acids (Chapter 2) Flashcards
STRUCTURE OF RNA AND DNA
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What are the two examples of nucleic acids ?
DNA + RNA
What does DNA stand for and what is the function of it ?
- deoxyribonucleic acid
- It stores genetic information
What is the sugar in DNA?
Deoxyribose
What does RNA stand for?
Ribonucleic acid
What is the function of RNA?
It transfers genetic information from the nucleus to the ribosome
What is the sugar in RNA?
Ribose
What are DNA and RNA (apart from nucleic acids, they are also …) ?
They are polymers
What is the basic structure of nucleotides
- A phosphate group
- A Pentose sugar
- A nitrogen- containing base (nitrogenous base)
What are polynucleotides?
Nucleotides join together to form polynucleotides
What type of reaction do nucleotides join together by?
A condensation reaction
What is formed between the sugar of one nucleotide and the phosphate of another nucleotide (what type of bond) ? , and what is the new structure called ?
Type of bond :Phosphodiester bond
New structure: dinucleotide
The bases on the two strands of DNA attach to each other by what type of bonds?
by hydrogen bonds (E.g. cytosine and guanine)
What is the chain of sugars and phosphates referred to as?
The sugar phosphate backbone
What causes a double helix in DNA?
Coiling in the polymer due to interactions between nearby DNA monomers
As the two DNA strands run in opposite directions, they are referred to as …
As being antiparallel to one another.
Is specifically asked, why are the DNA strands being synthesised in opposite directions?
- DNA has antiparallel strands
2, Nucleotides aligned different,y on each strand - Enzymes such as polymerase have active sites with specific shape
- Only 3 carbon ends can bind with active site of DNA polymerase ,the polymerase enzymes therefore travel in opposite directions
Complementary base pairing
2 polynucleotides can join together by what type of bond ?
Hydrogen bond, each base can only join one other base
What are the four types of nitrogenous bases in DNA ?
Adenine [A], Thymine [T] , Guanine [G], Cytosine [C]
What is the base pairing for the four nitrogenous bases in DNA ?
Adenine will always join with thymine, forming two hydrogen bonds.
Guanine will always join with cytosine, forming three hydrogen bonds
There will be equal amounts of ? in the polynucleotide ?
Complementary bases
RNA has some differences to DNA which are :
- the sugar in RNA is ribosome rather than deoxyribose
- The base uracil (U) replaces thymine.
Uracil pairs with adenine in the formation of RNA
-RNA polynucleotides are single stranded
What are the four types of nitrogenous bases in RNA ?
Adenine [A], Uracil [U], Guanine [G], Cytosine [C]