Molecular Genetics Flashcards
How many nitrogenous bases are there?
4
What is the backbone made out of in DNA?
Phosphate and Sugar
it repeats
Bases are bonded to..
sugars, not directly the phosphate.
The sugar in DNA is..
deoxyribose = 5 carbon sugar (pentose sugar)
Chargaff’s Rule
amount of A = T
amount of C = G
Nucleotides
sugar, phosphate, and one base
Purines and Pyrimidines
Purines - A and G = 2 rings
Pyrimidines - C and T = 1 ring
Double Helix
- the shape of dna
- two strands parallel to each other
Types of bonds in DNA
Hydrogen bonds between bases
Covalent bonds between sugar and phosphate
G and C are triple hydrogen bonded, A ant T are double hydrogen bonded
The enzymes involved in DNA replication
DNA helicase - seperates the two stands
DNA polymerase - adds new nucleotides to the unzipped original DNA molecule
DNA ligase - seals the new nucleotides into place.
DNA is replicated in a..
semi-conservative matter
which means that each new DNA molecule has one orginal and new strand
DNA replcation occurs in the nucleus.
DNA vs RNA
- RNA has ribose sugar instead of deoxyribose
- RNA has uracil instead of thymine
- RNA is a single stranded structure.
Types of RNA
mRNA - carries the coding sequence for protein synthesis
tRNA - molecules carries the anticodons to the ribosomes and decodes the mRNA into a protein
rRNA - makes up the structure of ribosomes. made in the nucleolus but shipped to the cytoplasm.
Transcription
occurs in the nucleus of eukaryotes and cytoplasm of prokaryotes
one of the DNA strands is used as a template to make RNA.
RNA Polymerase
binds to DNA and seperates the two stands, and one of the strands is used as a template for making RNA.