BIO CHEM 6 Flashcards
Which of the following statements regarding cyclin-dependent protein kinase is not correct?
Their activity is regulated by cyclins
They can alter the activity of proteins involve in the progression of cells through cell cycle
Their activity fluctuates during cell cycle
Each type of cell contains one specific form
Their activity is regulated by changes in gene expression, protein phosphorylation and proteolysis
Each type of cell contains one specific form
Which of the following statements regarding cyclins is not correct?
They can become linked to ubiquitin
They catalyze the phosphorylation of protein
They contain specific amino acid sequence that target them for proteolysis
They are activated and degraded during cell cycle
They are activated and degraded during cell cycle
Ubiquitin is a
Protein kinase
Protease
Component of the electron transport system
Protein that tags another protein for proteolysis
Protein that tags another protein for proteolysis
Cdk2/cyclinE functions in
G2/M transition
G2
M
G1/S transition
G1/S transition
In which phase of cell cycle is DNA replicated?
G1 phase
S phase
G2 phase
M phase
S phase
Cyclin dependent kinases which control progression through cell cycle checkpoints are totally activated by which of the following
Binding to cyclin, plus phosphorylation by a Cdk activating protein kinase
Binding to cyclins
Phosphorylation by Cdk activating protein kinase
Phosphorylation by a tyrosine kinase
Binding to cyclin, plus phosphorylation by a Cdk activating protein kinase
At the end of each phase of cell cycle cyclins activating Cdks in that phase are inactivated irreversibly by
Multiple phosphorylations
De-phosphorylation
Ubiquitinylation
Destabilizing by proteolysis in a proteosome
Destabilizing by proteolysis in a proteosome
At which cell cycle checkpoint, cell cycle is halted if cell’s DNA is damaged
G1 – S
S – G2
G2 – M
G0 – G1
G1 – S
Which of the following occurs in meiosis but not in mitosis?
Attachment of spindle fibers to kinetochore
Replication of DNA prior to start of cell division
Separation of sister chromatids at anaphase
Pairing of homologous chromosomes at metaphase plate
Pairing of homologous chromosomes at metaphase plate
Passage of a cell through stages of cell cycle is controlled by a protein kinase that phosphorylates many different proteins at appropriate times
Cdk activating kinase
Cyclin-dependent kinase
Cyclins
Tyrosine kinase
Cyclin-dependent kinase
Proto-oncogenes can be transformed to oncogenes by all of the following mechanisms except
Elimination of their start signals for translation During a viral infection cycle Chromosomal rearrangements Chemically induced mutagenesis Radiation induced mutation
Elimination of their start signals for translation
Oncogenes do not encode for
Trans-membrane protein receptors
Growth factors
DNA-dependent RNA polymerase
Cytoplasmic G-proteins and protein kinases
DNA-dependent RNA polymerase
Programmed cell death is termed as
Metastasis
Apoptosis
Proliferation
Mitotic termination
Apoptosis
Which of the following could be coded by a tumor-supressor gene?
A protein that helps prevent progression through cell cycle
A protein that helps prevent apoptosis
A protein that codes for a DNA repair enzyme
A protein that forms part of a growth factor signaling pathway
A protein that helps prevent progression through cell cycle
How does Ras oncogene contribute to cancers?
It codes for an anti-apoptotic protein, produced in abnormally large amounts
It codes for a GTPase switch protein, which in its mutated form cannot be switched off
It codes for a transcription factor produced abnormally in large amounts
A growth factor that is continually active
It codes for a GTPase switch protein, which in its mutated form cannot be switched off
Which property of p53 enables it to prevent the development of cancer?
It is a transcription factor that causes protein production which stimulates the cell cycle
It prevents replication of cells with damaged DNA
It prevents cells from triggering apoptosis
It stimulates synthesis of DNA repair enzymes that replace telomere sequence lost during cell division
It prevents replication of cells with damaged DNA
The characteristic of malignant other than a benign tumor is
Undergoes metastasis
Develops blood supply
Cell divides an unlimited number of times
Grows without needing a growth signal
Undergoes metastasis
The mutation which cannot give rise to an oncogene
Addition or deletion of a base producing a nonsense message and an inactive protein product
A point mutation changing just one amino acid in protein product
A translocation, putting gene under control of strong promoter producing over expression
A point mutation producing stop codon, premature termination
Addition or deletion of a base producing a nonsense message and an inactive protein produc
Which of the following about Rb tumor suppressor protein is correct?
It binds E2F transcription factor and prevents cell from entering S phase until a mitogenic signal is received
It is activated when phosphorylated by Cdk
It is a transcription factor
When a mitogenic signal is received, it binds the transcription factor E2F and thus stimulates the cell to enter S phase
It binds E2F transcription factor and prevents cell from entering S phase until a mitogenic signal is received
Migration of cancerous cells from the site of origin to other part of the body forming secondary tumors is called
Diapedesis
Metastasis
Proliferation
Apoptosis
Metastasis
If enthalpy change for a reaction is zero, then ∆G° equals to
-T∆S°
T∆S°
-∆H°
lnkeq
-T∆S°
∆G° is defined as the
Residual energy present in the reactants at equilibrium
Residual energy present in the products at equilibrium
Difference in the residual energy of reactants and products at equilibrium
Energy required in converting one mole of reactants to one mole of products
Energy required in converting one mole of reactants to one mole of products
For a reaction if ∆G° is positive, then
The products will be favored
The reactants will be favored
The concentration of the reactants and products will be equal
All of the reactant will be converted to products
The reactants will be favored
Unfolding of regular secondary protein structure causes
Large decrease in the entropy of the protein
Little increase in the entropy of protein
No change in the entropy of the protein
Large increase in the entropy of the protein
Large increase in the entropy of the protein
The study of energy relationships and conversions in biological systems is called as
Biophysics
Biotechnology
Bioenergetics
Microbiology
Bioenergetics
The relationship between K‘eq and ∆G‘° is
∆G‘° = RTlnK‘eq ∆G‘° = -RTK‘eq ∆G‘° = RK‘eq ∆G‘° = -RK‘eq
∆G‘° = -RTK‘eq
What does first law of thermodynamics state?
Energy can neither be destroyed nor created
Energy cannot be 100 percent efficiently transformed from one type to another
All living organisms are composed of cells
Input of heat energy increases the rate of movement of atoms and molecules
Energy can neither be destroyed nor created
If ∆G‘° of the reaction A → B is -40kJ/mol under
standard conditions then the reaction
Will never reach equilibrium
Will not occur spontaneously
Will proceed at a rapid rate
Will proceed from left to right spontaneously
Will proceed from left to right spontaneously
What is the relationship between ∆G and ∆G‘°?
∆G = ∆G‘° + RTln([products]/[reactants]) ∆G = ∆G‘° – RTln([products]/[reactants]) ∆G = ∆G‘° + RTln([reactants]/[products]) ∆G = ∆G‘° – RTln([reactants]/[products])
∆G = ∆G‘° + RTln([products]/[reactants])
Which of the following statements is false?
The reaction tends to go in the forward direction if ∆G is large and positive
The reaction tends to move in the backward direction if ∆G is large and negative
The system is at equilibrium if ∆G = 0
The reaction tends to move in the backward direction if ∆G is large and positive
The reaction tends to move in the backward direction if ∆G is large and positive
Anabolism and catabolism are chemically linked in the form of
ADP
ATP
Phosphodiester linkage
ASP
ATP
Which of the following statements is false about ATP hydrolysis?
It is highly exergonic
Activation energy is relatively high
∆G‘°=-30.5kJ/mol
∆G‘°=30.5kJ/mol
d. ∆G‘°=30.5kJ/mol
An endergonic reaction
Proceeds spontaneously
Does not require activation energy
Releases energy
Requires energy
Requires energy
An exergonic reaction
Proceeds spontaneously
Does not require activation energy
Releases energy
Requires energy
Releases energy
Phosphoryl groups are derivatives of
Phosphorous acid
Phosphoric acid
Acetic acid
Citric acid
Phosphoric acid
Water does a nucleophilic attack on phosphate monoester producing
Phosphorous chloride
Phosphorous sulfide
Inorganic phosphate
Organic phosphate
Inorganic phosphate
The phosphate groups used during glycolysis are
Organic
Inorganic
Neutral
None
Inorganic
Which of the following is false about acetyl-coA?
It is a thioester
It has a large, negative standard free energy of hydrolysis
It contains phosphorous atom in the position occupied by an oxygen atom in oxygen esters
It contains sulfur atom in the position occupied by an oxygen tom in oxygen esters
It contains phosphorous atom in the position occupied by an oxygen atom in oxygen esters
An example for chemical to osmotic energy conversion that occurs in living organisms
ATP-driven muscle contraction
ATP-dependent photon emission in fireflies
light-induced electron flow in chloroplasts
ATP-driven active transport across a membrane
ATP-driven active transport across a membrane
An example for chemical to electromagnetic energy conversion that occurs in living organisms
ATP-driven muscle contraction
ATP-dependent photon emission in fireflies
light-induced electron flow in chloroplasts
ATP-driven active transport across a membrane
ATP-dependent photon emission in fireflies
An example for chemical to mechanical energy conversion that occurs in living organisms
ATP-driven muscle contraction
ATP-dependent photon emission in fireflies
light-induced electron flow in chloroplasts
ATP-driven active transport across a membrane
ATP-driven muscle contraction
