Glossary of Tortora Microbiology Chap 8

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This organism contains a single, covalently closed circular molecule of DNA?
This organism has several pieces of DNA (complexed w/histones)in the cells nucleus
This organisms genes are frequently split into noncoding regions and coding regions
Coding Regions are called?
Non Coding Regions are called?
A group of related genes that are attached to one another are called?
What does DNA mean?
Deoxyribonucleic acid
What does RNA mean?
Ribonuicleic acid
What kinds of bonds join the nucleotides within a particular strand of DNA?
Phosphatediester bonds
What kinds of bonds from between the two strands of DNA?
Hydrogen bonds
How many base pairs are formed in DNA?
How many bonds stablize the base pair Adenine-Thynine?
How many bonds stablize the base pair Cytosine-guanine?
When we say the two strands are exact oposite we are saying they are?
Strands that run in opposite direction are said to be?
What are the purines?
Adenine and Guanine
What are the Pyrimidines?
Thynine and cytosine
When each new strand of DNA consists of one old and one new strand we say this is?
Semiconservative replication
3 limitations of DNA Polymerare III in terms of DNA replication
Unidirectional, Primer dependent, and Template dependent
Origin of replication for DNA occurs most often at which bond? Why?
the A-T bond as it is only connected by 2 Hydrogen bonds so it is weaker than C-G
This is the alternating sugar and phosphate molecules held together by convalent bonds
DNA backbone
The phosphate spans from 3' carbon of one sugar to 5' carbon of next, you count clockwise from Oxygen
DNA Backbone
When it is comprised of 2 complementary and antiparallel strands we say it is a ?
Double Helix
When each strand of the orginal molecule serves a template for the synthesis of a complementary copy
DNA Replication
What is catalized by DNA Polymerase III?
DNA replication
When DNA Polymerase III only move in one direction 5'-3' can only copy off template that runs 3'to 5'
Unidirectional limitation
The initiation of DNA synthesis is started at the orgin of Replication which is recognized by?
Bacteria have how many Origins of Replications?
Eukaryotic cells have how many ORI? why?
Multiple ORI to speed up replication
What is the initial primer for DNA Polymerase III to start catalyzing?
The two strands at the replication fork are called the?
leading strand and lagging strand
The 2 regions on each direction of ORI?
Replication fork
This strand runs 5' phosphate to 3' hydroxyl and DNA synthesis occurs continously
Leading strand
This strand runs 3' to 5' and synthesis occurs discontinously
Lagging strand
What are the fragments called that Lagging strand synthesis uses they are 5' to 3'
Okazaki fragments
What is the first step in Synthesis of Lagging strand?
Helicase unwinds double helix, then primase synthesis small fragments of RNA to provide free 3' OH group
What is the second step in Synthesis of Lagging strand?
DNA Polymerase III adds deoxyribonucleotides until it reaches primer of next fragment
What is the third step in Synthesis of Lagging strand?
DNA Polymerase I removes RNA primer and replaces it with DNA
What is the fourth step in Synthesis of Lagging strand?
DNA ligase provides final phosphodiester bond
Extra DNA at end of synthesis that causes DNA to get smaller and smaller (count down mechanisms
2 steps of Protein Synthesis
Transcription and Translation
Transcription is what?
Steps of Transcription going from one nucleic acid to another nucleic acid
Initiation, Elongation and Termination
When the RNA Polymerase binds to promoter (start signal) DNA sequence located "Upstream" of gene
Initiation of Transcription
This process does not require a primer but does require a template (single strand of DNA)
Elongation step of transcription
When RNA Polymerase Core Enzyme catalyzes formation of a phosphodiester bonds between ribonucleotides
When a mRNA "copy" of the DNA template is made
Synthesis of a complementary strand of RNA from a DNA template.
This means that more than one protein will be made from that mRNA molecule
Polygenic mRNA
Genes coding for related enzymes frequently occur together in a cluster
Messenger RNA mRNA is said to be _______ when it contains the genetic information to translate more than one protein
Most polycistronic mRNA is found in what type of organism?
In eukaryotes RNA transcripts must be processed before being used in translation
Post Transcriptional Modification
The changes to mRNA include addition of a 5' cap and 3' poly A tail and removal of introns and exons are joined together
Post Transcriptional Modification
Mature mRNA consists of
Ribosomes and spliceosomes
in mRNA 3 bases together is a
One codon specifies
1 amino acid
The start codon is
AUG Methionine
The 3 stop codons or nonsense codons are?
UAA, UAG, UGA can be remembered by
U Are Awful, U Are Gross, U Go Away
Most amino acids are signaled by several alternative codons a situation referred to as the
Degeneracy of the code
This is an adaptor molecule and has 2 specificites
tRNA or transfer RNA
The two specificites of tRNA are?
amino acids and mRNA
3 bases in DNA are defined as a
3 bases in mRNA are defined as a
3 bases in tRNA are defined as a
Anti codons
In this step of translation ribosome binds to start codon in mRNA
In elongation step of translation mRNA binds to mostly small subunits this large subunit has 2 binding site for tRNA known as
A (acceptor) site and P (Peptide) site
The A site is for?
Attachment site for new amino acyl tRNA
the p site is for?
site where tRNA holds growing peptide
In translation when ribosome reaches a stop codon, polypeptide is released and the ribosome dissociates this is
Termination step
RNA synthesis =
When biosynthetic enzymes are not produced if their product is present in the medium
Enzyme Repression
In Enzyme repression _____ is usually the final product of an anabolic pathway
Enzyme is synthesized only when its substrate is present
Enzyme Induction
Organism does not waste energy synthesizing unneeded enzymes
Enzyme Repression
Organism does not synthesize enzymes until they are needed
Enzyme Induction
Induction and repression act at the level of
These enzymes are not subject to induction or repression and synthesize continuously in the growing cell
Constitutive enzymes
These are key cellular enzymes required for growth under all nutritional conditions
constitutive enzymes
This is a heritable change in the nucleotide sequence of DNA
Two classes of mutations
Frame shift and point mutations
3 types of point mutations
Silent, Missense, Nonsense
When free DNA is incorporated into a "competant" recipient cell
Transformation requires ____ for uptake and processing of DNA
All transformal strands have
DNA binding proteins, Nucleases, Single stranded DNA binding Proteins, Rec A
When Bacterial DNA is transformed via a virus
A Capsid containing bacterial DNA is a
Transducing Phage
Process by which genetic information is passed directly
Fertility extra pieces of DNA
F Plasmids
F+ cell attaches to f- cell through its pilus

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