Nucleic Acids Flashcards
what is a nucleic acid?
a macromolecule
what is the monomer of a nucleic acid? what is a polymer?
nucleotide
polynucleotides
what are the components of a nucleotide?
a nitrogen base + a 5-carbon sugar + phosphate (functional group)
what are the 2 types of nucleic acids?
- Deoxyribonucleic acid (DNA)
2. Ribonucleic acid (RNA)
what is the 5-carbon sugar in the structure of RNA? what is the 5-carbon sugar in the structure of DNA? how do these 2 sugars differ?
RNA –> ribose
DNA –> deoxyribose
different because there is no hydroxyl group (OH) on 2’ carbon in a deoxyribose (2nd carbon after O)
how many different nitrogenous bases can nucleic acids be made of? what are the 2 types?
5 different nitrogenous bases
- Single-ringed pyrimidines
- double-ringed purines
what are the 3 Single-ringed pyrimidines?
- cytosine
- thymine
- uracil
what are the 2 double-ringed purines?
- adenine
2. guanine
which nitrogenous bases does DNA use?
- thymine
- cytosine
- adenine
- guanine
which nitrogenous bases does RNA use?
- uracil
- cytosine
- adenine
- guanine
how are polynucleotides formed?
formed by monomers link together by dehydration reactions to form a polymer
what are the 2 ends of nucleotide polymers? how can you tell them apart?
5’ end –> has a phosphate attached to the 5’ carbon
3’ end –> has a hydroxyl attached to the 3’ carbon
what is the covalent bond joining two nucleotides called?
Phosphodiester bond
where does a phosphodiester bond form? which end does a new nucleotide always add to?
Forms between a phosphate from one nucleotide and the hydroxyl group on the 3’ carbon on another nucleotide
-always ends to the 3’ end
what is the backbone of a polynucleotide made of? what extends out from backbone?
made of repeating pattern of sugar-phosphate units
-nitrogenous bases extend out from backbone
what is the role of DNA?
storing hereditary information in the form of genes
-Essential component of chromosomes
what do genes contain?
contains instructions to make a polypeptide
what is RNA responsible for in the cell?
Responsible for transcribing DNA and translating it
into protein
how many strands do RNA have? how many does DNA have?
Most RNA molecules are single stranded
-DNA is double
how many polynucleotides do DNA molecules have? what shape do they form? where are the components of DNA located?
- two polynucleotides
- spiral around an axis forming a double helix
- Sugar-phosphate backbone on outside and paired nitrogenous bases on inside
how do the 2 strands in DNA run in relation to each other?
antiparallel –> if parent strand runs 3’ to 5’, than daughter strand runs 5’ to 3’
how are the two strands in DNA held together?
held together by hydrogen bonds between the paired nitrogenous bases
what er the nitrogen base pairs in DNA?
Adenine & thymine
guanine & cytosine
