BIO CHEM 6 Flashcards by ROLLIE ESTEVES

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

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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

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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

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Cdk2/cyclinE functions in

G2/M transition
G2
M
G1/S transition

G1/S transition

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In which phase of cell cycle is DNA replicated?

G1 phase
S phase
G2 phase
M phase

S phase

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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

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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

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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

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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

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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

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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

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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

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Programmed cell death is termed as

Metastasis
Apoptosis
Proliferation
Mitotic termination

Apoptosis

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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

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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

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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

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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

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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

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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

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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

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If enthalpy change for a reaction is zero, then ∆G° equals to

-T∆S°
T∆S°
-∆H°
lnkeq

-T∆S°

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∆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

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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

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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

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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

An example for electromagnetic to electrical 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

light-induced electron flow in chloroplasts

Which of the following statements about redox potential is false? NADH/NAD+ redox pair has the least redox potential Oxygen/H2O redox pair has the highest redox potential The components of electron transport chain are organized in terms of their redox potential The redox potential of a system is usually compared with the potential of the hydrogen electrode

NADH/NAD+ redox pair has the least redox potential

Which out of the following is not a flavoprotein? Succinate dehydrogenase Cytochrome c Xanthine oxidase NADH dehydrogenase-Qreductase

Cytochrome c

Which out of the following has the highest redox potential? NAD FMN FAD O2

Which one out of the following is not a NAD+ requiring enzyme? Lactate dehydrogenase Pyruvate dehydrogenase complex Maltate dehydrogenase Acyl co-A dehydrogenase

Acyl co-A dehydrogenase

Which of the following enzyme catalyses the direct transfer and incorporation of O2 into a substrate molecule is Reductase Oxidase Oxygenase Peroxidase

Oxygenase

Which of the following statements is incorrect about oxidase? They catalyze reactions involving hydrogen peroxide They catalyze reaction using O2 as a hydrogen acceptor They catalyze reactions using niacin as coenzyme They catalyze reactions of direct incorporation of O2 into the substrate

They catalyze reaction using O2 as a hydrogen acceptor

Loss of electrons can be termed as Metabolism Anabolism Oxidation Reduction

Oxidation

Gain of electrons can be termed as Metabolism Anabolism Oxidation Reduction

Reduction

Which of the following enzyme catalyzes the first step in the catabolism of ethanol? Alcohol dehydrogenase Lactate dehydrogenase Glutamate dehydrogenase Malate dehydrogenase

Alcohol dehydrogenase

Which out of the following enzymes can utilize both NAD+ and NADP+ as a coenzyme? Glutamate dehydrogenase Alcohol dehydrogenase Aldehyde dehydrogenase Glycerol-3-P ddehydrogenase

Glutamate dehydrogenase

Which of the following enzyme catalyzes the first step of glycolysis? Hexokinase Pyruvate kinase Glucokinase Phosphofructokinase-1

Hexokinase

The general term used for the anaerobic degradation of glucose to obtain energy is Anabolism Oxidation Fermentation Metabolism

Fermentation

Whenever the cell’s ATP supply is depleted, which of the following enzyme’s activity is increased? Hexokinase Pyruvate kinase Glucokinase Phosphofructokinase-1

Phosphofructokinase-1

Cleavage of Fructose 1, 6-biophosphate yields Two aldoses Two ketoses An aldose and a ketose Only a ketose

An aldose and a ketose

Dihydroxyacetone phosphate is rapidly and reversibly converted to Glyceraldehyde 3-phosphate 1, 3-bis-phosphoglycerate Fructose 1, 6-bisphosphate Fructose 6-phosphate

Glyceraldehyde 3-phosphate

The first step in the payoff phase of glycolysis is Reduction of 1, 3-bisphosphoglycerate to glyceraldehyde 3-phosphate Oxidation of glyceraldehyde 3-phosphate to 1, 3-bisphosphoglycerate Reversible conversion of dihydroxyacetone phosphate to glyceraldehyde 3-phosphate Irreversible conversion of dihydroxyacetone phosphate to glyceraldehyde 3-phosphate

Oxidation of glyceraldehyde 3-phosphate to 1, 3-bisphosphoglycerate

The substrate used in the last step of glycolysis is Glyceraldehyde 3-phosphate Pyruvate Phosphoenolpyruvate 1, 3-bisphosphoglycerate

Phosphoenolpyruvate

High concentration of glucose 6-phosphate is inhibitory to Hexokinase Pyruvate kinase Glucokinase Phosphofructokinase-1

Hexokinase

The product formed in the first substrate level phosphorylation in glycolysis is Pyruvate 3-phosphoglycerate 1, 3-bisphosphoglycerate 2-phosphoglycerate

3-phosphoglycerate

Glycolysis converts Glucose into pyruvate Glucose into phosphoenolpyruvate Fructose into pyruvate Fructose into phosphoenolpyruvate

Glucose into pyruvate

The deficiency of which of the following enzyme leads to galactosemia? Galactokinase Pyruvate kinase PFK-1 PFK-2

Galactokinase

The conversion of which of the following involves two nucleotide derivatives? Galactose 1-phosphate to glucose 1-phosphate Galactose 1-phosphate to fructose 1-phosphate Fructose 1-phosphate to glucose 1-phosphate Lactose 1-phosphate to glucose 1-phosphate

Galactose 1-phosphate to glucose 1-phosphate

Which of the following enzyme is responsible for the conversion of glucose 1-phosphate to glucose 6-phosphate? Glycogen phosphorylase Isomerase Phosphoglucomutase Epimerase

Phosphoglucomutase

The product formed in the isomerization of mannose 6-phosphate Fructose 6-phosphate Glucose 6-phosphate 2-phosphoglycerate 3-phosphoglycerate

Fructose 6-phosphate

Which of the following enzyme is present in saliva? Hexokinase Alpha amylase Fructokinase Triose kinase

Alpha amylase

Which of the following conversions is not catalyzed by hexokinase? D-Glucose to glucose 6-phosphate D-Fructose to fructose 6-phosphate D-Mannose to mannose 6-phosphate D-Fructose to fructose 1-phosphate

D-Fructose to fructose 1-phosphate

Hydrolysis of lactose yields D-galactose and D-glucose D-glucose and D-glucose D-galactose and D-fructose D-fructose and D-glucose

D-galactose and D-glucose

Hydrolysis of sucrose yields D-galactose and D-glucose D-glucose and D-glucose D-galactose and D-fructose D-fructose and D-glucose

D-fructose and D-glucose

Maltose hydrolysis yields D-galactose and D-glucose 2-Dglucose n-Dglucose 2-Dfructose

2-Dglucose

Dextrin hydrolysis yields D-galactose and D-glucose 2-Dglucose n-Dglucose 2-Dfructose

n-Dglucose

Which of the following is true about the enzyme producing NADH from a triose phosphate in the glycolytic pathway? It produces 1, 3-biphosphoglycerate and NADH It catalyzes irreversible reaction It uses NAD+ and dihydroxyacetone ph zosphate as substrates It uses FADH2 and glyceraldehyde 3-phosphate as substrates

It produces 1, 3-biphosphoglycerate and NADH

The major factor(s) determining whether glucose is oxidized by aerobic or anaerobic glycolysis is/are Ca2+ FADH2 NADH and the ATP/ADP ratio Presence of high AMP

NADH and the ATP/ADP ratio

When glucose is converted to lactate by anaerobic glycolysis, equivalent number of ATPs derived is? 1 2 3 4

molecules of lactate during anaerobic glycolysis, which of the following statements is false? Glyceraldehyde 3-P dehydrogenase reaction produces 2 ATP molecules Lactate dehydrogenase reaction produces no ATP Pyruvate kinase reaction produces 2 ATP molecules Phosphofructokinase-1 reaction uses 1 ATP molecule

Glyceraldehyde 3-P dehydrogenase reaction produces 2 ATP molecules

In the reduction of pyruvate to lactate, which of the following is regenerated? H+ NADH NAD+ Na+

NAD+

For its activity, pyruvate decarboxylase requires Mg2+ Ca2+ Na+ H+

Mg2+

TPP (thiamine pyrophosphate) is derived from Vitamin A Vitamin B1 Vitamin C Vitamin B2

Vitamin B1

80. The end products in ethanol fermentation are a. Ethanol and CO2 b. Ethanol and O2 c. Ethanol, H2 and CO2 d. Ethanol, O2 and CO2

Ethanol and CO2

Enzyme involved in the pathway of ethanol fermentation? Hexokinase Pyruvate decarboxylase Pyruvate dehydrogenase Pyruvate kinase

Pyruvate decarboxylase

Enzyme involved in the pathway of synthesis of acetyl-coA Hexokinase Pyruvate decarboxylase Pyruvate dehydrogenase Pyruvate kinase

Pyruvate dehydrogenase

Which of the following is not an important precursor of glucose in animals? Lactate Pyruvate Glycerol Glucose 6-phosphate

Glucose 6-phosphate

Which of the following statements is false about gluconeogenesis? From the hydrolysis of tri-acyl-glycerol, fatty acids can be used as a carbon source From red blood cells, lactate can be used as a carbon source From the hydrolysis of tri-acyl-glycerol, glycerol is converted to glucose in gluconeogenesis From muscle vigorous muscle activity, lactate can be used as a carbon source

From the hydrolysis of tri-acyl-glycerol, fatty acids can be used as a carbon source

The enzyme which catalyzes the conversion of pyruvate to oxaloacetate Pyruvate carboxylase Pyruvate dehydrogenase Pyruvate kinase Phosphofructokinase-1

Pyruvate carboxylase

Oxaloacetate is reduced to malate by Pyruvate carboxylase Malate dehydrogenase Pyruvate kinase Phosphofructokinase-1

Malate dehydrogenase

Gluconeogenesis involves conversion of Glucose to pyruvate Pyruvate to glucose Phosphoenolpyruvate to glucose Pyruvate to fructose

Pyruvate to glucose

Which of the following organisms cannot covert acetyl-coA derived from fatty acids into glucose? Animals Plants Bacteria Virus

Animals

89. Formation of one molecule of glucose from pyruvate requires 4 ATP, 2 GTP and 2 NADH 3 ATP, 2 GTP and 2 NADH 4 ATP, 1 GTP and 2 NADH 2 ATP, 2 GTP and 2 NADH

4 ATP, 2 GTP and 2 NADH

Ethanol is oxidized to acetaldehyde in the liver cytoplasm by Alcohol dehydrogenase Alcohol carboxylase Pyruvate carboxylase Pyruvate kinase

Alcohol dehydrogenase

The main source of glucose carbons for gluconeogenesis is Guanine Alanine Cysteine Threonine

Alanine

Which of the following statements about gluconeogenesis is correct? Pyruvate is first converted to phosphoenolpyruvate by phosphoenolpyruvate carboxykinase Fructose 1, 6-biphosphatase converts fructose 1, 6-bisphosphate into fructose 1-phosphate Glucose 6-phosphatase hydrolyzes glucose 6-phosphate to release glucose into the blood Glucose 6-phosphatase hydrolyzes glucose 6-phosphate and is found in liver and muscle

Glucose 6-phosphatase hydrolyzes glucose 6-phosphate to release glucose into the blood

In the pentose phosphate pathway, the major products are Ribulose and NADPH Ribulose and NADH Ribulose and NAD+ Ribulose and ATP

Ribulose and NADPH

The first reaction of the pentose phosphate pathway is Oxidation of glucose 6-phosphate to 6-phosphoglucono-δ-lactone Oxidation of 6-phosphogluconate to ketopentose ribulose 5-phosphate Reduction of 6-phosphoglucono-δ-lactone to glucose 6-phosphate Reduction of ketopentose ribulose 5-phosphate to 6-phosphogluconate

Oxidation of glucose 6-phosphate to 6-phosphoglucono-δ-lactone

Which of the following statements is correct about oxidative pentose phosphate pathway? It generates NADH It oxidizes NADPH to NADP+ The pathway supplies ribose 5-phosphate and NADPH in the quantities the cell requires Glucose 6-phosphatase catalyzes the rate limiting reaction of the pathway

The pathway supplies ribose 5-phosphate and NADPH in the quantities the cell requires

Which one out of the following enzymes acts in pentose phosphate pathway? Aldolase Glycogen phosphorylase Pyruvate kinase q6-phosphogluconate dehydrogenase

q6-phosphogluconate dehydrogenase

Oxidation of 3 molecules of glucose by pentose phosphate pathway results in the production of 3 molecules of pentose, 6 molecules of NADPH and 3 molecules of CO2 4 molecules of pentose, 6 molecules of NADPH and 3 molecules of CO2 4 molecules of pentose, 3 molecules of NADPH and 3 molecules of CO2 3 molecules of pentose, 4 molecules of NADPH and 3 molecules of CO2

3 molecules of pentose, 6 molecules of NADPH and 3 molecules of CO2

The main function of pentose phosphate pathway is Supply NADP+ Supply NADH Supply energy Supply pentoses and NADPH

Supply pentoses and NADPH

One of the following statements is correct about pentose phosphate pathway It generates 6 moles of CO2 for each mole of glucose consumed It generates 38 mol of ATP per mole of glucose consumed It is a reductive pathway that consumes NADH Present in plants but not in animals

It generates 6 moles of CO2 for each mole of glucose consumed

Which of the following statements is correct about reductive pentose phosphate pathway? It is not reversible Transketolase transfers 3 carbon units Transaldose transfers 2 carbon units Pentoses can provide glycolytic intermediates

Pentoses can provide glycolytic intermediates

The use of NADPH generated from pentose phosphate pathway cannot be Can be oxidized in the electron transport chain to provide 38 ATPs Used for the synthesis of fatty acids Used for the macrophageal functions Used for steroid synthesis

Can be oxidized in the electron transport chain to provide 38 ATPs

Conversion of xylulose 5-phosphate to ribulose 5-phosphate is catalyzed by Phosphopentose epimerase Transaldolase Transketolase Phosphopentose isomerase

Phosphopentose epimerase

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BIO CHEM 6 Flashcards

(103 cards)