آزمون بیوشیمی دکتری قارچ شناسی پزشکی 27-10-1399 به صورت دیجی فرم

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زمان تکمیل این آزمون 50 دقیقه میباشد

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مرحله بعد

نام و نام خانوادگی خود را وارد نمایید *

تایید

کد ملی خود را وارد نمایید *

تایید

What body conditions favor gluconeogenesis over glycolysis? (0.25 نمره)

Low cellular levels of pyruvate

High blood sugar

Starvation

Increasing cellular levels of AMP

تایید

In gluconeogenesis, how can the reaction carried out by pyruvate kinase be reversed?

A- Pyruvate carboxylate converts pyruvate to oxaloacetate, which is converted by PEP carboxykinase into phosphoenolpyruvate (PEP)

B- A phosphatase can be used to dephosphorylate pyruvate into phosphoenolpyruvate (PEP)

C- PEP carboxykinase converts pyruvate to phosphoenolpyruvate (PEP)

D- Pyruvate kinase carries out a reversible reaction, and no other enzymes are needed

(0.25 نمره)

تایید

Which glycolytic reaction cannot be directly reversed in gluconeogenesis? (0.25 نمره)

Glyceraldehyde 3-phosphate → 1,3-bisphosphoglycerate

Glucose → glucose-6-phosphate

1,3-bisphosphoglycerate → 3-phosphoglycerate

Glucose-6-phosphate → fructose-6-phosphate

تایید

How are electrons extracted from the citric acid cycle for use in the electron transport chain? (0.25 نمره)

Oxidation of NAD+ and FAD

Oxidation of ATP and GTP

Reduction of NAD+ and FAD

Reduction of ATP and GTP

تایید

What important reducing agent is an important product of the pentose phosphate pathway? (0.25 نمره)

NADPH

NADP+

FADH2

NADH

تایید

نام سه ترکیب موجود در sample loading buffer با ذکر دلیل استفاده را در تکنیک الکتروفورز بیان نمایید؟ (0.75 نمره)

تایید

What carbohydrates are reactants in glycolysis? (0.25 نمره)

Glucose only

Neither glucose or sucrose directly participate in glycolysis

Glucose and sucrose

Sucrose only

تایید

How many total molecules of ATP are synthesized from ADP via glycolysis of a single molecule of glucose? (0.25 نمره)

تایید

What is the name of the process involved in the conversion of glucose to glycogen? (0.25 نمره)

Gluconeogenesis

Glycolysis

Glycogenesis

Glucogenolysis

تایید

In order to be added to a growing glycogen chain, glucose must first be linked by which of the following molecules? (0.25 نمره)

UDP

ADP

GDP

ATP

تایید

In which organisms does glycolysis occur? (0.25 نمره)

Anaerobic organisms only

Aerobic organisms only

Neither aerobic or anaerobic organisms

Both aerobic and anaerobic organisms

تایید

The pentose phosphate pathway is an important metabolic pathway within cells that allows them to synthesize two essential products. What are these two products, and what do they do? A- Fructose-2,6-bisphosphate, which plays a major regulatory role in glycolysis and gluconeogenesis, and glycerol-3-phosphate, which plays a role in the synthesis of triglycerides and phospholipids. B- Glutathione, which helps to maintain a reducing environment inside of cells, and 2,3-bisphosphoglycerate, which helps to reduce hemoglobin's affinity for O2. C- NADPH, which is used in reductive biosynthesis reactions, and Ribose-5-Phosphate, which is used as a major precursor to generate nucleotides D- NADH and FADH2, both of which are used to generate ATP in the cell via oxidative phosphorylation (0.25 نمره)

تایید

Given that the pyruvate dehydrogenase complex is product-inhibited, which of the following molecules would act as an inhibitor to it? (0.25 نمره)

Acetyl-CoA

NAD+

Pyruvate

Phosphoenolpyruvate

تایید

High cellular concentrations of what molecule would inhibit the entry of pyruvate into the citric acid cycle? (0.25 نمره)

NADH

Pyruvate

Coenzyme A

AMP

تایید

When would you expect glycogen synthase to be activated? (0.25 نمره)

When glycogen synthase is phosphorylated

When protein phosphatase I is activated

When protein kinase A is activated

When glucagon is in high concentration

تایید

How does ingestion of high amounts of ethanol affect gluconeogenesis?

I. High amounts of ethanol get oxidized producing NADH.

II. High levels of NADH inhibit gluconeogenesis.

III. High levels of NADH stimulate gluconeogenesis.

IV. High amounts of ethanol get oxidized producing NADP.

(0.25 نمره)

I and III

I and II

II and IV

I and IV

تایید

The citric acid cycle is __________. (0.25 نمره)

anabolic

catabolic

both anabolic and catabolic

neither anabolic, nor catabolic

تایید

In gluconeogenesis, where is oxaloacetate sequestered, and how is it able to reach the cytoplasm?

A- In the mitochondrial matrix; a carrier protein binds to oxaloacetate and traverses the mitochondrial membrane into the cytoplasm.

B- In the intermembrane space of the mitochondria; a carrier protein binds to oxaloacetate and traverses the mitochondrial membrane into the cytoplasm.

C- In the mitochondrial matrix; malate dehydrogenase reduces oxaloacetate to malate, which goes into the cytoplasm, and is converted back into oxaloacetate by malate dehydrogenase.

D- In the intermembrane space of the mitochondria; malate dehydrogenase reduces oxaloacetate to malate, which goes into the cytoplasm, and is converted back into oxaloacetate by malate dehydrogenase.

(0.25 نمره)

تایید

How many molecules of oxygen (O2) are required to complete the reactions of aerobic respiration beginning with four molecules of glucose? (0.25 نمره)

تایید

One important chemical transformation that occurs in the pentose phosphate pathway is the conversion of glucose-6-phosphate (G6P) to ribulose-5-phosphate (R5P), which is shown below. G6P+2NADP++H2O→R5P+CO2+2NADPH

The conversion shown above is an example of which of the following type of reaction?

(0.25 نمره)

Oxidation of glucose-6-phosphate

Isomerization of glucose-6-phosphate

Reduction of glucose-6-phosphate

Decarboxylation of glucose-6-phosphate

تایید

Which statement concerning the glycolytic and gluconeogenic pathways is correct? (0.25 نمره)

Both are anabolic

Gluconeogenesis is anabolic and glycolysis is catabolic

Both are catabolic

Gluconeogenesis is catabolic and glycolysis is anabolic

تایید

What is the approximate total yield of ATP that is produced via the Krebs cycle and subsequent oxidative phosphorylation of a single molecule of acetyl CoA? (0.25 نمره)

تایید

In the redox reaction: pyruvate + NADH + H+ ⇋ lactate + NAD+, which reactant is oxidized, and which is reduced? (0.25 نمره)

Lactate is reduced and NAD+ is oxidized

Lactate is reduced and pyruvate is oxidized

NADH is reduced and pyruvate is oxidized

Pyruvate is reduced and NADH is oxidized

تایید

How many molecules of acetyl CoA, an acetyl group attached to ‘coenzyme A’, are produced from a single molecule of glucose for participation in the Krebs cycle? (0.25 نمره)

تایید

Which of these molecules is not a product of the citric acid cycle? (0.25 نمره)

CO2

Flavin mononucleotide (FMN)

Pyruvate

NADH

تایید

What is the major distinction between NADH and NADPH in biochemistry?

A- NADH and NADPH serve the same function in all reactions

B- NADH is oxidized in catabolic reactions to produce ATP, wheres NADPH serves as a reducing agent in anabolic reactions

C- NADH is used in reactions to create ATP, whereas NADPH is used in reactions to produce ADP

D- NADPH is oxidized in catabolic reactions to produce ATP, wheres NADH serves as a reducing agent in anabolic reactions

(0.25 نمره)

تایید

What PHRASE is the best description for the energetics of glycolysis? 1. Overall under typical cellular conditions, glycolysis has a positive free-energy change, though there are steps of both positive and negative free-energy change 2. Each step of glycolysis has a negative free-energy change 3.Each step of glycolysis has a positive free-energy change 4.Overall under typical cellular conditions, glycolysis has a negative free-energy change, though there are steps of both positive and negative free-energy change (0.25 نمره)

تایید

Which enzyme catalyzes the conversion of citrate to isocitrate? (0.25 نمره)

Citrate isomerase

Citrate synthase

Aconitase

Phosphatase

تایید

سوال تشریحی ( لطفا پاسخ دهید): چه تفاوتی بین سیستم بافری پیوسته و ناپیوسته در الکتروفورز وجود دارد ؟ (1.25 نمره)

تایید

The in vitro conversion of glucose to glucose-6-phosphate― glucose + Pi ⇋ G-6-P + H2O ― is highly endergonic, though in the setting of glycolysis proceeds in a spontaneous and irreversible fashion. How is this achieved? (0.25 نمره)

Through coupled ATP hydrolysis reactions

Through coupled ADP condensation reactions

Endergonic reactions are always spontaneous and irreversible

High concentrations of H2O shift equilibrium to favor G-6-P formation

تایید