Molecular Genetics

Question 0

James Watson and Francis Crick

Answer 0

Found the structure of DNA

Rosalind Franklin and Maurice Wilkins work were critical for this (X-Ray crystallography)

Question 1

Alfred Hershey and Mary Chase

Answer 1

Used bacteriophages to prove that DNA must be the genetic material

Question 2

Backbone of DNA is made of

Answer 2

Sugar-phosphate components

Question 3

DNA rungs are made up of

Answer 3

Nitrogenous bases

Question 4

Nucleotide is made up of what

Answer 4

A sugar (deoxyribose) attached to a phosphate and a nitrogen base

Question 5

Nitrogen bases of DNA are

Answer 5

Adenine with Thymine

Guanine with Cytosine

Question 6

Nucleic acid strands are always what to each other

Answer 6

Anti-parallel

Question 7

Semi conservative

Answer 7

Replication of DNA-daughter cell has one old strand and one new strand

Question 8

DNA replication

Answer 8

1-begins at origin of replication
2-enzyme helicase unravels DNA(replication bubble formed)
3-DNA polymerases catalyze elongation of new DNA
4-DNA polymerase III matches nucleotides 5’ to 3’
5-continuous on 5’ to 3’(leading strand), segments in 3’ to 5’(lagging)
6-lagging strand pieces=Okazaki fragments, sealed by DNA ligase

Question 9

Factors contributing to the accuracy of DNA replication

Answer 9

1-specificity of base pairing
2-mismatch repair=special repair enzymes fix incorrectly paired nucleotides
3-nucleotide excision repair=incorrectly placed nucleotides are removed by enzymes(nucleases) and filled with correct nucleotides

Question 10

Telomeres

Answer 10

• To avoid losing the terminal genes, the linear ends of eukaryotic chromosomes are capped with these.
• short repetitive nucleotide sequences that do not contain genes

Question 11

A bacterial chromosome

Answer 11

One double-stranded, circular DNA molecule associated with a small amount of protein

Question 12

Eukaryotic chromosomes

Answer 12

Linear DNA molecules associated with large amounts of protein
Chromatin: DNA and proteins are packed together as this

Question 13

Gene expression

Answer 13

The process by which DNA direct the synthesis of proteins or in some cases RNAs

Question 14

The one gene one polypeptide hypothesis

Answer 14

Each gene codes for a polypeptide, which can be or can constitute a part of a protein

Question 15

Transcription

Answer 15

The synthesis of RNA using DNA as a template. It takes place in the nucleus of eukaryotic cells

Question 16

mRNA

Answer 16

Produced during transcription and it carries the genetic message of DNA to protein making machinery of the cell in the cytoplasm which is the ribosome

Question 17

How to produce mRNA

Answer 17

Transcription results in pre-mRNA, which undergoes RNA processing to yield the final mRNA

Question 18

mRNA in prokaryotes

Answer 18

Transcription results directly in mRNA, which is not processed. Transcription and translation can occur simultaneously

Question 19

Translation

Answer 19

The production of a polypeptide chain using the mRNA transcript and occurs at the ribosomes

Question 20

Triplet code

Answer 20

The instructions for building a polypeptide chain are written as a series of three nucleotide groups called the triplet code

Question 21

Template strand

Answer 21

During transcription, only one strand of DNA is transcribed and it is called the template strand. The mRNA that is produced to said to be complementary to the original DNA strand. The mRNA base triplets are called codons. They are written in the 5 to 3 direction