Microbiology test #3 – Flashcards

binds to the DNA molecule and prevents transcription.

capable of amino acid production

repression

an amino acid activates the repressor so that the repressor binds to the operator and prevents transcription

true

low and lactose is present

cAMP; switches on

active and can bind to the operator

true

true

5

inactive and cannot bind to the operator

trp repressor

a mutation that results in changing a codon such that a different amino acid is specified

a mutation that changes a codon into a different codon, but both codons specify the same amino acids; this causes no change in the resulting polypeptide

a mutation resulting from an insertion or deletion of bases that causes a change in the reading frame of the mRNA

a mutation that changes a codon encoding an amino acid to a stop codon, resulting in premature termination of polypeptide synthesis

all DNA present in a cell virus; Bacteria and archaea usually have on set; eukaryotes have 2 sets

specific set of genes

collection of observable characteristics

the change of non-virulent organisms into virulent ones. (Griffith 1928)

bacteriophage T2 infection as model; labeld with 32P; protein coat with 35 S; only DNA entered cell, but both new DNA and protein coats synthesized in new viruses indication DNA had genetic info for both of these viral components.

polymers of nucleotides that are linked together by phosphodiester bonds

the nitrogenous base they contain; the sugars they contain; whether they are single or double stranded

adenine, guanine, cytosine, and thymine

deoxyribose

is esterified to sugar carbon

covalent bonds between the 3'- hydroxyl of one sugar and a 5'-phosphate attached to an adjacent sugar

adenine & thymine pair by 2 hydrogen bonds and guanine and cytosine pair by 3 hydrogen bonds

when the 2 strands twist around each other

adenine, guanine, cytosine, and uracil

ribose

messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA)

separates DNA

are added to provide 3-prime starting point for 2nd strand

enzyme that synthesizes DNA

enzyme that forms a bond between the short DNA strands

adds nucleotides to the 3 prime end of primers

circular with bidirectional replication from single origin

keep strands apart for replication

breaks one strand of DNA to relieve tension from rapid unwinding of double helix and prevents supercoiling

carried out by DNA polymerase III; removal of mismatched base from 3' end; its not 100% effective

the basic unit of genetic info; nucleic acid sequence that codes tRNA or rRNA; linear sequence of nucleotides; codons are found in mRNA and code for single amino acids

is located at the start of the gene; is the recognition/binding site for RNA polymerase;

is transcribed into mRNA but is not translated into amino acids

RNA synthesis under the direction of DNA

RNA produced has complementary sequence to the template DNA, 3 types of RNA are produced

carries the message for protein synthesis

carries amino acids durin protein synthesis

molecules are components of ribosomes

only short segment of DNA transcribe

core RNA polymerase dissociates from template DNA

genetic info is stored in DNA and then transcribed into mRNA and the translated into protein

the 61 codons that specify amino acids

the 3 codons used as translation termination signals

up to 6 different codons can code for a single amino acid

some protists use a single stop codon, the other two code for amino acids instead

synthesis of polypeptide directed by sequence of nucleotides in mRNA

when the amino acid attaches to the tRNA

is the site of protein synthesis and is responsible for translation

contributes to structure of ribosome; binds to mRNA to initiate protein synthesis

peptidyl, aminoacy, exit

UAA

transcription initiation, transcription elongation, and translation

Binding of regulatory protein at a regulatory region on DNA promotes transcription initiation

inactive protein is activated by inducer; active protein is inactivated by inhibitor

a microorganism is grown on glucose, if an amino acid is added to the medium the organism can turn off the synthesis. In the absence of the amino acid a regulatory protein called a repressor is made, but it is unable to bind to DNA and prevent transcription

regulation prohibits lactose production, the inducer becomes active and reacts with the repressor and inactivates

binds to operator and inhibits transcription; bends DNA; prevents RNA polymerase from accessing promoter

regulates in response to presence or absence of glucose

code for enzymes needed to synthesize tryptophan

no exposure to external things, errors in DNA replication, can come from actions of transposons

caused by agents that directly damage DNA

deliberate modification of organisms genetic info by directly changing the sequence of nucleic acids in it genome

procedures used to carry out genetic engineering

generation of a large number of genetically identical DNA molecules

use of organisms to form useful products

use of microbes to manufacture important compounds or the use of microbes as products in their own right

genetic restriction enzyme; genetic cloning and cDNA synthesis; gel electrophoresis; southern blotting

recognize and bind specific sequences in DNA called recognition sites

used to separate molecules based on their charge and molecular weight

separate DNA molecules -> transfer -> hybridize

1982; produced new source of human insulin

enables gene amplification

simplifies gene cloning; generates DNA fragments; diagnostic purpose

plasmin's, phages & viruses, cosmids, artificial chromosomes

replicate autonomously and easy to purify

are engineered phage genomes previously genetically modified to include restriction sites

do not exist in nature; constructed to contain features from both phages and plasmids

used when large fragments of DNA must be cloned

cloned genes in the new host cell

isolation of gene product; polyhistidine tagging; isolation of protein by metal ion resin

in vivo expression and regulation

study of molecular organization or genomes, their info content, an gene products

most commonly used method, referred to as the chain-termination DNA sequencing method, uses dideoxynucleoside triphosphates

1995; J Craig Venter & Hamilton smith; 4 stage process

femtogrmas of DNA from a single cell are amplified to microorganisms of DNA needed for sequencing

analysis of genome date using computers

process that locates genes in the genome map

determination of how genome works

can determine which genes are expressed at a specific time

spotted rays prepared by robotic application of DNA probe