Chapter 9 notes Flashcards
Define genetics
The study of genes and genomes, and their role in the biology of an organism
What is the relationship between genomes and organisms
helps cells survive by giving instructions to produce gene products
Define genome
instructions or blueprint for cell to survive
The genome is the sum total of ______ carried within a cell
DNA
What do most of the genome exist in the form of
chromosomes (but are also in the form of plasmids)
The genome of viruses differs from that of euk and pro
in that euk/pro genome are just DNA but viruses are DNA and RNA
What is the structure of euk chromosomes
DNA molecules tightly wound around histone proteins
What is the structure of bacterial chromosomes
condensed and secured DNA into a packet by means of a different type of protein
Euk have ______ chromosomes where pro have ______ chromosome
linear; circular
The specific sequence of DNA bases encoded in the genome = __________ results in the ________, which is the set of observable characteristics of an individual resulting from the interaction of its genotype with the environement
genotype; phenotype
A genome is divided into _________
genes
Define gene
fundamental unit of heredity responsible for a given trait in an organism; it is a portion of the chromosome that provides information for a given cell function
T/F some genes in a genome can be non-coding
T
Genes are a specific segment of DNA that contains the necessary information to make a molecule of _______ or _________
protein; RNA
The genetic information of all organisms is stored in the genome, this allows
cells to function
Gene expression is __________
regulated
The cells must be able to copy (___________) its DNA and pass its genetic information to offspring
replicate
Genes and genomes can be analyzed using __________ techniques
lab
Using lab techniques genes and genomes can be __________ to produce recombinant orgnaisms with novel phenotype
manipulated
What bonds hold together base pairings in DNA
H bonds
In a simpler system of pro, circulate chromosomes are packaged by the action of enzyme called _________
topoisomerase
What does topoisomerase do
coils the chromosomes into a tight bundle by introducing a reversible series of twists into the DNA molecule
The basic unit of DNA is a
nucleotide
What is a nucleotide composed of
phosphate, deoxyribose sugar, and a N base
How many H bonds between:
A and T/U
G and C
2
3
Function of helicase
unzipping the DNA helix
Function of primase
synthesizing an RNA primer
Function of ligase
final binding of nicks in DNA during synthesis and repair
Function of DNA polymerase lll
adding bases to the new DNA chain, proofreading the chain for mistakes
Function of DNA polymerase l
removing RNA primers, replacing gaps between Ozaki fragments with correct nucleotides, repairing mismatches bases
Nucleotides are added to the _____ end
3’
The template strand is an original __________ dna strand and is retained in the daughter molecule
parental
The preservation of the parent molecule with one strand, is termed ________ ___________, and helps explain the reliability and accuracy of replication
semiconservative replication
What is the origin of replication
serves as the place where replication is initiated
What does helicase form
replication fork with two template strands
Where does the origin of replication usually begin
at an A and T rich area because it requires less energy to break the 2 H bonds
When does replication begin
when RNA primers are synthesized by a primase at the origin of replication
When is the replication of lagging strand completed
when DNA polymerase l removes the RNA primers from the okazaki fragments and fills in the missing segments with correct complementary DNA nucleotides
The replacement strand is not completely bonded to the finished part of the new strand of lagging strand so an enzyme ________ makes these final phosphate sugars connect
ligase
Replication proceeds from the _____ to _____ ends
5’ to 3’
What is the origin of replication in binary fission
oriC
What does replisome do in binary fission
copies DNA strands in binary fission for replication
In binary fission what direction does replication occur
both directions
What is the flow for information
DNA –> RNA –> Proteins
Define transcription
when the master code DNA is first used to synthesize RNA
Define translation
information contained in the RNA is then used to produce proteins
We transcribe the DNA into ___________
ssRNA
one gene differs from another in the order and number of it’s _________
codons
Each codon/triplet represents a code for a particular _______
amino acid
The order of triplets directs a protein’s ________ structure–the order and type of AA in the chain–which determines it’s ________ and _______
structure; shape and size
Proteins contribute significantly to the ________ by functioning as enzymes and structural molecules
phenotype
mRNA contains codes for
sequence of AA in proteins
Function of mRNA
carries the DNA master code to the ribosomes
Is mRNA translated
yes
tRNA contains codes for
specifying a given AA
tRNA contains codes for
specifying a given AA
Function of tRNA in cells
carries AA to ribosome during translationg
is tRNA translated
no
rRNA contains codes for
several large structural rRNA molecules
Function of rRNA in cells
forms the major part of a ribosome and participates in protein synthesis
Is rRNA translated
no
What is the template strand in transcription
part of the DNA genome that is transcribed
_________ _________ (proteins) bring RNA polymerase to the correct promoter in transcription
sigma factors
What is the promoter
specific region on the DNA that will be recognized by Sigma factors and RNA polymerase
Transcription makes
ssRNA
Translation makes
proteins
What is the one strand that will be transcribed in the 3’ to 5’ direction by RNA polymerase called
template strand
What occurs in initiation of transcription
guided by sigma factors RNA poly binds to DNA promoter site and DNA is unwound
What occurs in elongation of transcription
rna polymerase moves along the DNA strand adding complementary nucleotides as dictated by the template strand; mRNA strand is synthesized in the 5 –> direction
What occurs in the termination of transcription
polymerase continues transcribing until it reaches a termination site and the mRNA transcript is released to be translated
Define what mRNA is
a transcribed version of a structural gene or genes in DNA, copy the DNA gene but in RNA
What does rRNA do
read mRNA code, facilitate its interaction with tRNA and produces proteins
Prokaryotic ribosome is _____s
70
What is tRNA responsible for
recognizing the correct codon and bringing the correct AA to the ribosome during translation
tRNA contains an Anticodon and is charged with an AA = ____________
aminoacyl-tRNA
Ribosomes assemble on the _____ end of an mRNA transcript
5’
Ribosomes scan the mRNA until it reaches the ribosome binding side called the (in bacteria and archeae)
shine-dalgarno site
In translation what does AUG code for
formyl-methionine
What are operons
multiple genes encoded on one mRNA transcript
What is the ribosome binding site in eukarya
Kozak Se Q
In eukaryotic mRNA transcription is AUG start codon AA formyl methionine
NO only in bacteria and archaea
Where does transcription occur in euk
in the nucleus
Translation:
How does initiation begin
when a start codon (AUG) is encountered
Translation:
When does elongation start
with the filling of the A site by a second tRNA
Translation:
What is happening during the elongation phase
growing peptide chain
Translation proceeds by ribosome ________ mRNA
down
tRNA _____________ the code
translates
Translation:
What recognizes the stop codon and terminates translation
protein release factor
What catalyzes peptide bond formation in intiation
rRNA
What are the 3 termination codons
UAA, UAG, UGA
Translation:
What occurs in termination
tRNA encounters stop codon, and a special enzyme breaks the bond between the final tRNA and the finished polypeptide chain, releasing it from the ribosome
Multiple ______- read the same message concurrently to speed up translation
ribosomes
What is processed and transported immediately upon synthesis
protein folds
What is the mechanism of azythromycin
binds bacterial 50s ribosomal subunit to prevent translocation from A site to P site
Which target drug is bactericidal
azythromycin
What two drugs are bacteriostatic
chloramphenicol
tetracycline
What is the mechanism of chloramphenicol
formation of peptide bonds is blocked
What is the result of tetracycline
tRNA is blocked, no protein is synthesized
Is peptide bond formation energetically favorable
yes
Where is 50% of energy consumption in a typical bacterial cell accounted for
in translation
Each tRNA charging event uses _______ atp and assembly of ribosomes uses _____ GTP and each peptide addition uses _______ GTP and termination uses ______-
1
1
2
energy
What are the products of transcription by RNA poly
tRNA and mRNA and rRNA
What is synthesizing new covalent bonds between AA
rRNA–peptide bonds
What reads the message of the mRNA and brings the correct amino acid to be added to the peptide chain
tRNA
In euk what do we do after primary RNA transcript
splice out introns with a 5’ cap and polyA tail
mRNA transcrips are processed in euk to remove _______ and add cap and tail
introns
For viral genome DNA where is the location in euk and pro
euk: nucleus
pro: cytoplasm
For viral genome RNA where is it euk and pro
euk: cytoplasm
pro: cytoplasm
What occurs after viral replication
transcription and translation of viral proteins –> assemble and release
What sort of genetic information is in the genetics of Herpes
dsDNA
Herpes: encodes ______ viral proteins including own viral ______ ___________
84; DNA polymerase
What does the genome due in herpes
integrates genome into host genome for life of host
Where does acute infection occur
periphery epithelial cells
Does latency infection show visible symptoms
no
In the nucleus what happens with the site of initial herpes infection
integrates its genome into host (integrase)
What is the symptoms of herpes
cold sores
viral shedding
epithelial cell death
What enzyme is required for integration of the viral genome into the host genome
integrase
Bacteria have genetic defenses against viruses = _________
CRISPR
What is the sequence of retrovirus genetics
RNA to DNA to RNA to proteins
What is the enzyme that brings RNA to DNA in retrovirus genetics
transriptase
What is an example of retrovirus genetics
HIV
Define oncogene
gene that has the potential to cause cancer
Define gene regulation
genetic control processes, ensure protein/genes are expressed when needed
What does negative regulation do
turn OFF expression to make less of gene product
What does positive regulation do
turn ON gene expression to make more of gene product
_________ control of production of bioluminescence by autoinducer vibrio fisceri
positive
What does gene mutation rate of microbes depend on
genome composition and size
Within one organism what can change in the genome
- mutations
- recomboniation
Define recombination in genomes
rearrangement of DNA Se Q during replication
What genome changes can occur between organisms
conjugation
transformation
transduction
What is Conjugation genome changes
plasmid transfer
What is transformation genome changes
transfer of free DNA
What is transduction genome changes
transfer by viral delivery
Define mutations
change in wild type or normal chromosomal genome composition
Define spontaneous mutation
change in the dna arising from errors in replication that occurs without a known cause
What is induced mutation
results from exposure to known mutagens that damage DNA and interfere with its functioning
What is point mutaiton
addition, deletion, or substitution
What is missense mutation
change in the code that leads to placement of a different AA
What is a nonsense mutation
changes a normal codon into a stop codon that does not code for an AA and stops the production of the protein
what is the worst mutaiton
frameshift mutation
