12.3 Nucleic acids, ATP, Water & Inorganic Ions Flashcards
what does DNA stand for
deoxyribonucleic acid
what does RNA stand for
ribonucleic acid
DNA and RNA are…
important information carrying molecules
what does DNA do
holds genetic information
what does RNA do
transfers genetic info from DNA to the ribosomes
monomer in DNA
DNA nucleotide: a deoxyribose sugar, a phosphate group and a nitrogen containing base (adenine, cytosine, guanine or thymine)
monomer in RNA
RNA nucleotide: a ribose sugar, a phosphate group and a nitrogen containing base (adenine, cytosine, guanine or uracil)
polynucleotide formation
condensation reaction between 2 or more nucleotide monomers forming a phosphodiester bond
polynucleotide strands are formed when…
many nucleotides link to form a long chain
a phosphodiester bond forms between…
the phosphate group of 1 nucleotide to the 3rd C of the (D/R) sugar in the next nucleotide
what makes a nucleic acid very strong and stable
the sugar-phosphate backbone of the nucleic acid
structure of a DNA molecule
double helix
DNA consists of…
2 polynucleotide chains held together by many weak H bonds between specific complementary base pairings
how many H bonds are formed between Adenine and Thymine
2
how many H bonds are formed between Cytosine and Guanine
3
top of the chain
5’ to 3’
bottom of the chain
3’ to 5’
bonds in the backbone
phosphodiester
bonds that bring both the strands together
H bonds
How do you answer percentage questions DNA
If we are given the % of 1 base, we can use that to work out the % of the other complementary base. And then the % of the 2 other bases.
The sequence of the bases along the nucleotide chain is…
Variable (basis of the genetic code and how info is stored in DNA)
The function of DNA is that it…
Codes for the sequence of amino acids (3 bases = triplet = 1 amino acid).
Long strands of DNA code for…
The primary structure of polypeptide chains and proteins.
What is an mRNA molecule?
A relatively short polypeptide chain, which is normally a single stranded helix.
What is mRNA used to do?
To transfer genetic information from DNA to ribosomes.
Structure of DNA
Structure of RNA
sugar phosphate backbone with bases
DNA consists of…
2 antiparallel nucleotide strands
To make sure the 2 strands remain parallel (the same distance apart)…
Adenine pairs with Thymine and Cytosine pairs with Guanine.
What does it mean when we say the DNA is parallel?
The 2 strands of DNA run in opposite directions.
What does the 5’ and 3’ indicate?
Which carbon is involved in the phosphodiester bond.
If you follow the left hand chain up to the end at the top you would have…
A phosphate group attached to C5 on the deoxyribose sugar.