Molecular Biology Flashcards
What is DNA composed of
Deoxyribonucleotides
What are the components of deixyribonucleotides
A purine or pyrimidine base
A deoxyribose sugar
A phosphate group
What is a nucleotide
A molecule with all the components of deoxyribonucleotides
What is a nucleoside
A molecule with only the first two components of a nucleotide but no phosphate group
How many rings does a purine base have
it has 2 rings
how many rings does a pyrimidine base have
it only has 1 ring
What is DNAs primary structure
Its the sequence of the base pairs
What is DNAs secondary structure
Formed by the complimentary base pairing of two strands of DNA
How does base pairing of the secondary DNA structure occur
Thro hydrogen bonding between a purine and pyrimidine base that matches up to provide optimal hydrogen bonding contact
What does the back bone of DNA hold
It has the sugars and phosphates
What are the steps for the central dogma of molecular biology
Replication, transcription, translation
What happens during replication for the central dogma
DNA synthesis or copying DNA
What happens during transcription of the cental dogma
DNA provides template for production of messenger RNA (mRNA)
What is mRNA
in essence it “reads” the info in DNA and brings it to the site of protein synthesis, the ribosome
What happens during Translation of the central dogma
Process by which the info carried in mRNA is used to make actual proteins
What does mRNA provide for protein building
a template for the amino acids carried by transfer RNA (tRNA) to be build into proteins of the correct sequence
Reverse transcription
Some virus which are able to take RNA and reverse the process to create DNA
Semi-conservative replication
When creating new strains of DNA each new strand with always have at least one older stand as well as a newer one
What does RNA contain as basic components
Same as DNA which is has a Base, sugar and phosphate
What are the two structural differences between RNA and DNA
The sugar in RNA contains a hydroxyl group at the 2’ position
RNA does not contain the pyrimidine base thymine; it has the pyrimidine base of uracil
What differs in RNA compared to DNA with its secondary structure
Can use either intermolecular or intramolecular base pairing while DNA only has intermolecular base pairing
What can RNA do that DNA can not in terms of twisting and folding
DNA can only form double helix while RNA can Twist and fold in 3D forms to create tertiary structures
What are the different types of RNA and what are these based off of
based of their functions Messenger RNA (mRNA); carries message from DNA Transfer RNA (tRNA); brings amino acids to ribosome Ribosomal RNA (rRNA); part of the ribosome
what is a Transcription event
production of RNA based off a DNA template
What is RNA-polmerase
An enzyme which binds to the DNA and finds a promoter
What is a Promoter that is found by RNA-polimerase
tells the enzyme that this is the start of a gene and where transcription should begin
What is a stop site found by RNA-polimerase
Signals the end of a gene and where transcription should end
What are introns
Part of RNA which are not expressed in the protein and need to be removed thro RNA splicing before translation
What are Exons
Part of the RNA which holds the coding regions for proteins
Where does a codon on mRNA pair
it pairs with the anitcodon on tRNA and determines which amino acid is attached to the peptide chain
How many different codons can there be
64; with a 3 nucleotide code and 4 nucleotide bases
How many amino acids are there
20; meaning multiple codons can code for the same amino acid
what is degeneracy
Its demonstrates that with the 20 amino acids, means multiple codons can code for the same AA
What is an operon
a cluster of genes with related functions acting as a coordinated unit and controlled by a regulatory sequence
What are the components that comprise the operon
- structural genes
- promoter
- repressor
- activator
- operator
What are the structural genes in the operon for
code for proteins
what is the promoter in the operon
a region that influences the efficiency of gene transcription (enzymes recognizes where transcription should begin)
what is the repressor of the operon
a gene that codes for a protein which inhibits transcription of a specific gene of the operon when bound to DNA
what is a activator in the operon
a gene that codes for a protein which enhances transcription of a specific gene of the operon when bound to DNA
what is a operator in the operon
a sequence of DNA which can bind a repressor and/or an activator protein (controls when it can and can not transcript, an on off switch)
