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WorksheetsBMS I Exam 2 Review 3
Total questions: 40
Worksheet time: 21mins
What is the primary function of the pyruvate dehydrogenase complex?
Convert glucose to pyruvate
Convert pyruvate to acetyl-CoA
Convert acetyl-CoA to citric acid
Convert citrate to oxaloacetate
Which molecule inhibits the pyruvate dehydrogenase complex?
Pyruvate
Acetyl-CoA
NADH
Coenzyme A
Under what conditions does lactate typically form in muscles?
During aerobic respiration
During anaerobic glycolysis
During the citric acid cycle
During oxidative phosphorylation
Which enzyme is responsible for the conversion of pyruvate to lactate?
Lactate dehydrogenase
Pyruvate kinase
Phosphofructokinase-1
Alanine transaminase
What is the main purpose of converting pyruvate to lactate in anaerobic conditions?
To produce more ATP directly
To regenerate NAD+ from NADH
To produce acetyl-CoA
To increase glycolysis
Where does lactate go after it is produced in muscles?
It is used locally in the muscle for energy
It is transported to the liver for conversion to glucose
It is excreted as waste
It is directly used in the citric acid cycle
What process in the liver converts lactate back to glucose?
Glycolysis
Gluconeogenesis
The citric acid cycle
Glycogenolysis
Which cycle involves the recycling of lactate between muscles and the liver?
Urea cycle
Cori cycle
Krebs cycle
Calvin cycle
What is a common condition associated with the accumulation of lactate in muscles?
Muscle dystrophy
Lactic acidosis
Rhabdomyolysis
Myasthenia gravis
What is the primary factor leading to the production of lactate during intense exercise?
Low oxygen availability
High glucose availability
Increased ATP production
Low pyruvate levels
Which coenzyme does LDH use to catalyze the interconversion between lactate and pyruvate?
FAD
NADH/NAD+
Coenzyme A
ATP
How is the activity of lactate dehydrogenase regulated?
By changes in pH
By the availability of NADH/NAD+
By phosphorylation
By substrate concentration
What is the structural form of lactate dehydrogenase?
A single polypeptide chain
A dimer of identical subunits
A tetramer of subunits
An octamer of subunits
A deficiency in which B vitamin can lead to the development of pellagra, characterized by dermatitis, diarrhea, and dementia?
Vitamin B1 (Thiamine)
Vitamin B2 (Riboflavin)
Vitamin B3 (Niacin)
Vitamin B12 (Cobalamin)
Which B vitamin is crucial for DNA synthesis and its deficiency can lead to megaloblastic anemia?
Vitamin B6 (Pyridoxine)
Vitamin B7 (Biotin)
Vitamin B9 (Folate)
Vitamin B12 (Cobalamin)
A deficiency of which B vitamin can cause peripheral neuropathy and is often seen in individuals with chronic alcoholism?
Vitamin B1 (Thiamine)
Vitamin B3 (Niacin)
Vitamin B6 (Pyridoxine)
Vitamin B12 (Cobalamin)
A deficiency in which B vitamin is often associated with hair loss and skin rashes?
Vitamin B2 (Riboflavin)
Vitamin B7 (Biotin)
Vitamin B3 (Niacin)
Vitamin B6 (Pyridoxine)
Which vitamin B deficiency is particularly common in people with a condition called pernicious anemia?
Vitamin B2 (Riboflavin)
Vitamin B9 (Folate)
Vitamin B12 (Cobalamin)
Vitamin B6 (Pyridoxine)
What is the primary purpose of anapleurotic reactions in metabolism?
To generate ATP
To provide intermediates for biosynthetic pathways
To replenish intermediates, like those used in the citric acid cycle
To break down fatty acids
Which cycle is specifically replenished by anapleurotic reactions?
Glycolysis
Urea cycle
TCA Cycle
Calvin cycle
Which of the following reactions is an example of an anapleurotic reaction?
Conversion of pyruvate to acetyl-CoA
Conversion of oxaloacetate to phosphoenolpyruvate
Conversion of pyruvate to oxaloacetate
Conversion of citrate to isocitrate
Which enzyme catalyzes the conversion of pyruvate to oxaloacetate in an anapleurotic reaction?
Pyruvate dehydrogenase
Pyruvate carboxylase
Citrate synthase
Alpha-ketoglutarate dehydrogenase
What is the primary characteristic of an exergonic reaction?
It absorbs energy from the surroundings
It releases energy to the surroundings
It occurs only at high temperatures
It requires a catalyst to proceed
Which term describes the change in Gibbs free energy (ΔG) for an exergonic reaction?
Positive
Negative
Zero
Variable
In which of the following processes does an exergonic reaction occur?
Photosynthesis
Cellular respiration
Protein synthesis
DNA replication
What is the primary characteristic of an endergonic reaction?
It releases energy to the surroundings
It absorbs energy from the surroundings
It occurs spontaneously
It decreases the entropy of the system
Which term describes the change in Gibbs free energy (ΔG) for an endergonic reaction?
Positive
Negative
Zero
Variable
In which of the following processes does an endergonic reaction occur?
Cellular respiration
Hydrolysis of ATP
Synthesis of glucose in photosynthesis
Glycolysis
What does a negative Gibbs free energy change (ΔG) indicate about a reaction?
The reaction is at equilibrium
The reaction is endergonic and non-spontaneous
The reaction is exergonic and spontaneous
The reaction is reversible
What is the primary function of G proteins in cellular signaling?
To synthesize proteins
To act as intracellular second messengers
To transduce signals from G protein-coupled receptors (GPCRs) to intracellular effectors
To transport molecules across the cell membrane
Which component of the G protein is responsible for binding and hydrolyzing GTP?
Alpha subunit
Beta subunit
Gamma subunit
All three subunits together
How many subunits make up a typical G protein?
One
Two
Three
Four
Which of the following is the correct sequence of activation for a G protein?
GPCR → G protein → Effector
G protein → GPCR → Effector
GPCR → Effector → G protein
G protein → Effector → GPCR
What happens to the G protein alpha subunit after it binds GTP?
It dissociates from the beta and gamma subunits
It binds irreversibly to the GPCR
It binds to the effector molecule
It hydrolyzes ATP
What is the primary function of myoglobin in muscle tissue?
To transport oxygen to various tissues
To store oxygen for use during muscle contraction
To catalyze the breakdown of glycogen
To regulate blood pressure
In which tissues is myoglobin primarily found?
Liver and kidney
Heart and skeletal muscle
Blood and lymph
Brain and lung
In which tissues is hemoglobin predominantly found?
Heart and liver
Skeletal muscle and brain
Red blood cells (erythrocytes)
Skin and connective tissue
What structural characteristic of myoglobin helps it to efficiently store oxygen in muscle tissue?
Its tetrameric structure
Its single heme group with a high affinity for oxygen
Its ability to bind multiple oxygen molecules
Its interaction with hemoglobin in the blood
Which coenzyme is required by both ALT and AST for their catalytic activity?
NAD+
Coenzyme A
Pyridoxal phosphate (Vitamin B6)
FAD
In the ALT reaction, what is the product when alanine donates its amino group?
Aspartate
Pyruvate
α-Ketoglutarate
Oxaloacetate
