Beginning
All about DNA
DNA again.....
Replication
Transcription and Translation
100
Scientists did not know if DNA or protein was the genetic material. Experiments that led to discovery of DNA?
Fredrick Griffith
Hershey and Chase experiments.
100
DNA structure
Backbone
Bases and base pairing
Double helical
Sugar and phosphate
A,T,G,C and AT/GC.
100
•If there is 30% Adenine, how much Cytosine is present?
20%
100
What is a leading strand and lagging strand?
Leading strand made as a single strand and grows towards replication fork.
Lagging strand in short stretches called "Okazaki fragments".
100
What is transcription and translation? Do they have any similarities or differences?
Transcription- mRNA formed.
Translation- amino acid chain formed or a polypeptide chain is formed.
200
DNA structure discovery = amounts of bases
Erwin Chargaff showed that the 4 bases were equal.
200
The bonds present in the backbone between sugar and phosphate?
Phosphodiester bonds.
200
DNA replication?
When does this occur?What is a replication fork and origin of replication?
Replication is copying of information from parent DNA strand to the daughter DNA. Occurs before cell division.The starting point of replication is the origin of replication and DNA strands open up to form the replication fork.
200
____________enzyme joins the okazaki fragments together.Semiconservative model of replication?
Ligase enzyme.
The DNA strand formed is new and the information is copied from parent strand, one new and one old strand formed.
200
Difference between genetic code and a codon?
The three bases on DNA is the genetic code
300
Chargaff's rule
Adenine must pair with Thymine
Guanine must pair with Cytosine
300
What is a nucleotide?
What is the sugar called?
Basic subunit of DNA
Made of: Sugar, Phosphate and nitrogenous base.
Sugar: Pentose sugar, 5carbon ringed structure.
300
Enzymes involved in DNA replication?
Helicase
Ligase
topoisomerase
Polymerase.
300
•What would be the complementary DNA strand for the following DNA sequence?
DNA 5’-CGTATG-3
3'-GCATAC-5'
400
Female scientit who took X-ray diffraction pictures of DNA crystals.
Rosalind Franklin.
400
Bonds between nitrogen bases and number of bonds
Hydrogen bonds between base pairs.
A=T and 3 bases between G and C.
400
Before replication begins, RNA primers start addition of nucleotides to DNA strand. True/False
True.
RNA primer is synthesized by primase.
400
What is RNA and how is it different from DNA?
Ribose nucleic acid, Uracil in RNA IN place of Thymine in DNA.
500
First DNA model built in 1953, using Rosalind Franklin's diffraction pictures.
James Watson and Francis Crick
500
Why are the starnds of DNA antiparallel?
What are Purines and Pyrimidines and how many ring structures do they have?
The direction is 5'-3' and 3'-5'.
Purines are Adenine and Guanine (double ringed structures)
Pyrimidines are Thymine and cytosine (single ringed structures).
500
DNA polymerase can add nucleotides only to ____ end of the DNA strand. Thus the new DNA strand is built in the _______________ direction.
3' and 5'-3' end.
500
The three different types of RNA.
t-RNA, r-RNA and m-RNA.