Unit 2 Flashcards
What is the purpose for a promoter?
Sequence for the binding of RNA polymerase
What are sites for binding of gene regulatory proteins
Regulatory DNA sequences
_______ __________ proteins bind to the regulatory DNA sequences and used to turn Genes on and off
Gene regulatory proteins
A bacterial operon contains what 3 components?
Promoter
Operator
Structural gene
What are the functions of the operator?
Regulatory DNA sequence that can serve either as a repressor or activator
______ _______ turns genes off when bound to a specific protein
Repressor operators
_____ ________ turned genes on when bound to specific protein
Activator operators
Operators can also be _____ _____ which code for mRNA
Structural genes
Transcriptional control in bacteria can use a repressor operator. What is an example?
Tryptophan operon
What does the Lac operon use to control transciption in bacteria?
Uses both activator CAP and a repressor operator
What is the function of the lac operon?
Makes enzymes to break down lactose
When glucose is present, the lac operon is _____
Inactive
The operon is off
If have glucose is present but no lactose then what is bound? Is the operon on or off?
Repressor
Operon is off
When there is not glucose and no lactose what is bound to the operon? Is the operon on or off?
CAP and repressor bound but operon is still off
When lactose is present but not glucose what is bound to the lac operon? Is the operon on or off at this point?
CAP bound
Operon turned on
What is located upstream from the structural gene and contains a TATA box in eukaryotes?
Promoter
_______ are regulatory DNA sequences that are used instead of operons in eukaryotes
Enhancers
How many structural genes are there per promoter?
One structural gene
Explain the initiation of transciption?
General transcription factors assemble with RNA polymerase at the TATA box and specific transcription factors bind to enhancers
Eukaryotic genes are regulated by _________
A combination of proteins
what coordinates expression of many different genes?
Single gene regulatory protein
Through cell differentiation we get a
Combination of regulatory proteins
What are the functions of membranes?
Lipid bilayer of molecules
Transport barrier
Contains transport channels
Flexible, expandable, repairable
Membranes function to
Receive _______
______ and ______ molecules
Capacity for _______ and _______
Receive information
Import and export of molecules
Capacity for movement and expansion
______ code for proteins that cells need, such as genes for glycolysis, ribosomal proteins
House keeping genes
_________ code for proteins needed for a particular cell type such as Hb for RBCs and Ab genes for B cells
Specialized genes
Genes can be controlled by what 5 processes?
Transcriptional control RNA processing RNA transport control Translation control Protein activity control
What are parts of transcriptional control of gene expression?
Regulatory DNA sequences (site for binding of gene regulatory proteins)
Gene regulatory proteins that bind to regulatory DNA sequences that are used to turn on and off genes
_______ _____ is made up of a promoter, operon, and structural genes
Bacterial operon
_______ _____ turn off genes when bound to a specific protein
Repressor operators
______ ______ turn genes on when bound to specific protein
Activator operators
_______ genes code for mRNA
Structural genes
What is an example of a repressor operon?
Tryptophan operon
________ operon is always on and uses a repressor to turn it off when there is enough of the product W present
Tryptophan
____ operon uses both an activator and a repressor operator
Lac operon
When glucose and lactose are present the Lac Operon is _____
Off
What happens to the operators for the lac operon when glucose and lactose are present?
CAP protein is NOT bound so no transcription occurs
When glucose is present but lactose is not, is the lac operon on or off? And what are the operators doing?
Lac operon is off
CAP protein isn’t bound but the repressor is bound
When both glucose and lactose are not present is the lac operon on or off? What are the operator proteins doing?
Lac operon is off
Both the CAP protein and repressor are bound
When glucose isn’t present but lactose is, is the lac operon on or off? What are the operators doing?
Lac operon is on
CAP protein is bound, and RNA pol binds to the operator and begins transcribing
______ contains the TATA box
Promoter
_____ are remote from structural gene and are regulatory DNA sequences used instead of operators
Enhancers
How many structural genes are associated with each promoter in euk?
One structural gene per promoter
Enhancers are either _____ or _______
Activators or repressors
______ are proteins that bind to genes at enhancer sites and speed the rate of transcription
Activators
_______ are proteins that bind to selected sets of genes at sites known as silencers to slow transcription
Repressors
Where do repressors bind and where do activators bind?
Repressors bind at silencer sites
Activators bind at enhancer sites
_______ are adapter molecules that integrate signals from activators and perhaps repressors
Coactivators
_____________ position RNA pol at the start of transcription and initiate transcription process
Basal transcription factor
Euk genes regulated by a combination of proteins also known as __________ ______
Combinatorial control
What coordinates expression of many different genes? Ex: glucocorticoid receptor
Single gene regulatory protein
What transcriptional control is involved in cell differentiation
Combination of regulatory proteins
A form of transcriptional control in euk involves the _____ of DNA and euk ________ initiation
Packaging of DNA and euk transcription initiation
What are the 6 ways of controlling transcription in euk
Single gene regulatory proteins Combination of regulatory proteins Packaging DNA and euk transcription initiation RNA processing control Translation control Protein activity control
What are examples of RNA processing control
Capping
Polyadenylation
Alternative splicing
What are examples of translational control
MRNA transport to ribosomes
Initiation of translation
What are examples of protein activity control?
Phosphorylation/ dephosphoryation
Selective degradation
Membranes function in what 3 activities?
Receiving info
Import and export
Capacity for movement and expansion
What 2 components affect the fluidity of the lipid bilayer?
The hydrocarbon tail length
Degree of saturation
________ _____ affects length and saturation of hydrocarbon tails
Environmental temperature
______ prevents fluidity and enhances permeability barrier
Cholesterol
What are the 3 functions of fluidity?
1) cellular interaction
2) movement of proteins and lipids
3) fusion and division of membranes
Some lipids are necessary on the inside and some are necessary on outside of the cell. What are some examples of each?
Outside: glycolipids and phosphatidylcholine
Inside: protein kinase C, and phosphatidylinositol
_______ are involved in RANDOM lipid movement form one side of the lipid bilayer to the other
Scramblases
________ involved in SPECIFIC lipid movement within the bilayer
Filppases
Where does membrane synthesis occur in the cell?
In the ER
How are glycolipids delivered so they face outside the cell?
Transport vesicles
What are the 4 functions of membrane proteins?
1) membrane transport
2) anchors for stability
3) cell signaling receptors
4) enzymes for reactions
Sugars on the cell surface create ______ _____
Cell coat
Carbs on the cell surface are important in what 5 ways?
Protection, lubrication, recognition, interaction
What is the most common cation inside and outside the cell?
Inside the cell is K+
Outside the cell is Na+
How is the balance of ion concentrations maintained?
By membrane transport proteins and membrane permeability
______ molecules cannot pass through the bilayer
Hydrophilic
Passage rate is dependent on what?
Size and solubility
Small nonpolar molecules such as O2 and CO2 can or cannot pass the membrane?
Can pass the membrane
Uncharged molecules that are polar pass rapidly if ______ or _____, pass moderately if ______ or _____.
Ethanol or water
Glycerol or ethanol
Ions and charged molecules can or cannot pass the bilayer?
DO NOT pass
Large uncharged molecules such as amino acids, glucose and nucleosides do or do not pass the bilayer?
DO NOT pass
Transport of a charges molecules is dependent on ________ _______
Membrane potential
What is membrane potential?
Difference in voltage gradient
What is the electrochemical gradient?
Combined concentration and membrane potential gradient
These gradients work in opposite or same direction
What is coupled transport?
Uphill transport of one solute and downhill transport of another solute
Describe ATP driven pumps
Uphill transport of solutes with ATP hydrolysis
Describe Light driven pumps
Uphill transport of solutes with input of light energy
What are the stages of the Na/K pump?
1) Na attaches to pump
2) ATPase splits ATP-> ADP and the pump is phosphorylated
3) phosphorylation activates export of Na and import of K
4) K attaches to binding site
5) pump resets itself
in ______ water flows from high to low concentration
Osmosis
How is osmotic pressure maintained in animal cells?
Aquaporins
What regulates the cellular pH in animal cells?
Na+/H+ exchanger
Voltage gated channels are opened by _______ ______
Membrane potential
Ligand gated channels are opened by what?
Binding of ligand
Stress activated channels are opened how?
Physically/ mechanically opened
Ex: stereocilia
Cystic fibrosis is caused by defective ____ channels AKA as CFTR
Cl-
What happens in cystic fibrosis?
Mutated Cl- ion channels fail to transport Cl- in mucosa causing a shift in osmosis of water resulting in production of thick poorly flowing mucous
What are examples of excitatory neurotransmitters?
Ach (opens Na+ channels)
glutamate (opens Ca2+ channels)
What are examples of inhibitory neurotransmitters?
GABA and glycine (opens up Cl-)
What are two cells that form myelin and which one funcitons in the CNS? PNS?
CNS oligodendrocytes
PNS Schwann cells
What are the end products of glucose?
2 pyruvate, 2 NADH, 2 ATP
What are the end products of the citric acid cycle?
6 NADH, 2 FADH2, 2 GTP
Total oxidation of one glucose gives on average ______ ATP
30 ATP
