Gene Expression Flashcards
A sequence of DNA/RNA that codes for a molecule for the transmission of genes to offspring, also the basis of inheritance for phenotypic traits
Gene
Carries the genetic instructions used in the growth, development, functioning of all known living organisms
DNA
the DNA stretches which encode for specific proteins
gene
a biomolecule that contains genetic info
DNA
regulates the traits of an organism
gene
regulates gene regulation
DNA
a specific sequence present on a short stretch of DNA
gene
these are made up of either DNA or RNA
gene
a polymer of nucleotides
DNA
these are coded with hereditary information
genes
encodes genetic instructions
DNA
multistep process that ultimately results in the production of a functional gene product, either
RNA or proteins
gene expression
Ability of a cell to control or regulate what products (RNA or protein) it makes from its DNA
gene expression
2 main groups of genes
structural and regulatory
group of gene that are protein coding genes
structural genes
this group of gene constitutes about 20, 400 genes in the human body
structural genes
constitutes about 2% of human DNA
structural genes
group of genes that regulate the proteins that are produced by the structural genes and comprises 98% of human DNA
regulatory genes
type of gene structure which mainly comprises the operon-based gene clusters
prokaryotic gene structure
type of gene structure whose open reading frame is disturbed by the presence of introns
eukaryotic gene structure
type of gene structure where functionally-related genes occurs in operons
prokaryotic gene structure
type of gene structure where individual promoters regulate the genes
eukaryotic gene structure
for most genes the main site of control is the ______
transcription of DNA to RNA
in eukaryotes, gene expression is also controlled at _____ and _____
posttranscriptional, posttranslational
Transcription in eukaryotes requires transcription factors to bind the ____ of the promoter
TATA box
translation in prokaryotes is initiated by rRNA pairing with _______ in mRNA
SD box
a cluster of genes that are transcribed together to give a single messenger RNA (mRNA)
molecule, which therefore encodes multiple proteins
operon
the ___ gene codes for B-galactosidase
lacZ
lacZ hydrolyzes lactose to _____ and _____
galactose and glucose
the _____ gene codes for permease
lacY
lacY facilitates movement of
lactose into the cell
the _____ gene codes for thiogalactosidetransacetylase
lacA
lacA ______ lactose
acetylates
this is an example of a negative gene regulation
when glucose is available
this gene produces the repressor proteins
lacI
adenyl cyclase is inactive in the presence of _____, and CAP is not bound to cAMP
glucose
when only lactose is available, a small amount of it is converted into an isomer _____
allolactose
in the absence of glucose, _____ is active and cAMP is made and binds to the CAP
adenylyl cyclase
when only lactose available is an example of what type of regulation
positive regulation
the lacI gene is _____ and is always produced
constitutive
what happens when both glucose and lactose are present?
lac operon is uninduced, transcription is negligible
adenylyl cyclase is inhibited in the presence of ______ this process is known as ________
glucose, catabolite repression
tryptophan omepron includes ____ genes that encode enzymes needed for tryptophan biosynthesis along with a promoter and an operator
5
the trp operon is regulated by
trp repressor/attenuator
tryptophan which switches a repressor into its active site is called a
corepressor
the trp repressor binds and blocks transcription only when
tryptophan is present
this is a mechanism for reducing expression of the trp operon when levels of tryptophan are high
attenuation
in attenuation, rather than blocking initiation of transcription, it prevents _____ of transcription
completion
the section between the operator and the 1st gene of the operon is called the _____
leader
the leader encodes a short polypeptide and also contains an ______
attenuator sequence
attenuator does not encode a polypeptide but when transcribed into mRNA it can form ______
hairpin structures
the polypeptide encoded by the leader is short, just ________amino acids longs and it includes 2 Trp residues
14
trytophans are important because
(1) plenty Trp, ribosome wont have to wait for Trp-carrying tRNA (2) if little Trp: ribosome will stall at Trp codons
antiterminator hairpin in low Trp levels
2&3
terminator hairpin in low Trp levels
3&4
in low Trp levels, termination does not occur and RNA polymerase continues transcribing, producing a transcript that includes the
trpE-trpA genes
in high levels of Trp, trpE and trpA are
never transcribed
part of the eukaryotic gene sequence that is expressed, also the sequence that encodes polypeptides
exons
art of the eukaryotic gene sequence that is not expressed and come in between the exons
introns
in eukaryotic gene regulation, this is where RNA polymerase II binds
start site
RNA polymerase II is a complex of ____ proteins that synthesizes the mRNA
12
type of promoter in eukaryotic gene where DNA sequence is located abut 40 bases upstream of the start site
core promoter
the core promoter is found in all eukaryotic genes, and its most common is ____
TATA box
about _____ can bind the core promoter for gene expression complexes
50 proteins
this complex in the core promoter consists of the TATA binding protein which recognizes and binds to the TATA box
transcription factor II D
this protein in the core promoter helps the TATA binding protein interact with RNA polymerase II
transcription factor II B
segments of DNA found upstream of the core promoter
proximal (upstream) promoter
unlike core promoters, upstream promoters
vary from gene to gene
these are the DNA sequence that are away from the gene, maybe upstream or downstream
enhancer/silencer
the silencer binds ______ that increase the rate of transcription
special transcription factor proteins
this is the site of preinitiation complex formation
TATA box
this is the first step in transcription initiation in eukaryotes
preinitiation complex formation
when does formation of the preinitiation complex begins?
when the multi-subunit transcription factor binds to the TATA box
after TFIID binds to the TATA box what joins after?
RNA polymerase II
these are proteins involved in the process of converting or transcribing DNA into RNA
transcription factors
the main function of transcription factors is to help turn specific genes _____ by binding to nearby DNA
“on” or “off”
2 domains of transcription factors
DNA binding domain and transactivation domain
these attaches to specific DNA sequences that are upstream to a regulated gene
DNA binding domains
the DBDs are also called
promoter/response element
this is where other proteins (co-regulatory proteins) bind to the transcription factor
transactivation domain (TAD)
a 3rd element is sometimes present in transcription factors where it allows signaling molecules to bind the transcription
signal-sensing domain (SSD)
activator proteins bind to an _____ in the DNA
enhancer region
a DNA-bending protein brings the bound ______ closer to the promoter
activators
the activators bind to transcription factors and mediator proteins forming a _____
transcription initiation complex
the transcription initiation complex promotes the binding of RNA polymerase to the promoter, enhancing
gene expression
an autosomal dominant neurodegenarative disorder caused by mutations in the HTT gene
huntington’s disease (HD)
HTT gene encodes the
huntington protein
HD mutation involved expansion of _____ repeats in the HTT gene
CAG trinucleotide
this disease manifest with motor dysfunction, cognitive decline, and psychiatric symptoms
HD
an X-linked recessive disorder characterized by progressive muscle
degeneration and weakness
duchnne muscular dystrophy (DMD)
in DMD, the DMD gene encodes for
dystrophin
dystrophin is crucial for
muscle fiber integrity
patients with DMD experience delayed motor milestones, muscle weakness, and ___
cardiopulmonary complications
understanding gene expression of dystrophin has enabled the development of therapies like
exon skipping
exon skipping in DMD therapy aims to restore the reading frame of the DMD gene and produce functional albeit
shorter dystrophin protein
copolymer-based muscle membrane stabilization of dystrophic muscle occurs via
insertion of hydrophobic PPO block