DNA and Protein synthesis Flashcards
What is the structure of a nucleotide
3 points
1) It is made of a pentose sugar; phosphate and nitrogenous base
2) It is held together by covalent bonds
3) It has a phosphodiester and glycosidic bond
What are the key features of nucleotides?
4 points
1) they become phosphorylated when they contain more then one phosphate group
2) Form the monomer of nucleic acids = DNA and RNA
3) Help regulate metabolic pathways i.e ATP; ADP
4) May be components of co- enzymes
What is the structure of DNA?
4 points
1) Polymer made up of many nucleotides
2) Consists of two polynucleotide strands that form a double helix
3) The strands are antiparrallel are in a ‘5 3’ formation
4) Tightly wound around histone proteins in chromosomes
Why does the purine always pair with the pyrimidine?
It gives equal size rungs on the DNA ladder that form the double helix and helps enable stability
What is the key word to describe chromosomes if there identical?
Homologus
What are the key features of genes?
3 points
1) Sections of DNA
2) Codes for a particular characteristic
3) alternate forms of the gene arising in mutations are called alleles
How many bonds does adenine and thymine form?
Cytosine and guanine?
A and T = 2
C and G = 3
these are held together by hydrogen bonds
What is the formation of the double helix?
5’ 3’ from the 5 prime end (phosphate attached to the 5th carbon) to the 3 in an antiparrallel structure
What are the purines and what are the pyrimidines and what are there structures?
Purine = A + G = double ringed structure Pyrimidines = C + T = single ringed structure
What are the differences between DNA and RNA
4 points
1) RNA is single stranded
2) It uses uracil instead of thymine
3) It is made from ribosomes
4) it is oxygenated
What does the glycosidic and phosphodiester bond require?
A condensation reaction
What is semi conservative, conservative, dispersive?
Semi conservative = One new daughter strand and one complementary to the parent strand
Conservative = entirely new / entirely old
Dispersive = Dotted DNA molecules all broken up
What enzymes are involved in DNA replication and what are there functions?
Gyrase - unwinds DNA
Helicase - unzips DNA = hydrogen bonds are broken
Primase - Signals where the nucleotides are added
DNA polymerase- adds the nucleotides in a 5’ 3’ direction
DNA Ligase - sticks the lagging strand fragments
Good Hearts Pour Pots of Love
Which is the leading and lagging strand?
5'-3' = leading 3'-5' = lagging
What are okazaki fragments
Short sequences of DNA nucleotides which are synthesized discontinuously on the lagging strand during DNA replication.
This happens as only a certain amount of the lagging strand can unzip before it can be synthesized further