Biochem TUT Quiz

Which of the following exercise intensities would produce the greatest concentration of lactate after 30 seconds of exercise? - 250% VO2max - 35% VO2max - 90% VO2max - 60% VO2max

- 250% VO2max

For cross bridge release, it is necessary for _______ to attach to the myosin head - Tropomyosin - ATP - Calcium ions - Troponin - Sarcolemma

- ATP

Which of the following is/are major contributors to acidosis? - Pyruvate reduction to lactate - Electron transport chain - Sodium / potassium pump - Glycolysis - ATP hydrolysis

- ATP hydrolysis

When the neuron stimulates a muscle fiber, what molecule diffuses across the gap between them? - Calcium - Sodium and Potassium - Acetylcholine - Sodium

- Acetylcholine

Which of the following statements is CORRECT? - Increased lactate concentrations mean there is hypoxia and the system is in trouble - Acidosis refers to changes in pH brought about by stresses that surpass the mitochondria's capability to meet demand - Muscle lactate concentrations > 3 mmol/Liter are normal - Acidosis refers to hypoxic changes brought about by the mitochondria's incapability to meet demand

- Acidosis refers to changes in pH brought about by stresses that surpass the mitochondria's capability to meet demand

The pumping of protons across the inner mitochondrial membrane: - All answers are correct - Creates a proton gradient - Is known as the chemiosmotic model - Provides energy for the formation of ATP

- All answers are correct

Which of these is (are) required for the relaxation of a muscle fiber? - ATP - Ca2+ ion uptake into the sarcoplasmic reticulum - Acetylcholinesterase activity - No additional stimulation of the neuron - All of the above

- All of the above

What is given off as a by-product of cellular respiration during the conversion of pyruvic acid (a three-carbon molecule) into acetyl-CoA (a two-carbon molecule)? - Glucose - CH4 - H2O - CO2

- CO2

Which substance is released from the sarcoplasmic reticulum following spread of an action potential along the sarcolemma: - Sodium - Sodium and Potassium - Calcium - Acetylcholine

- Calcium

Which of the following represents an oxidation reaction in the electron transport chain? - Q to QH2 - Cyt c (Fe+3) to Cyt c (Fe+2) - Cyt b (Fe+2) to Cyt b (Fe+3) - FMN to FMNH2

- Cyt b (Fe+2) to Cyt b (Fe+3)

There are two main electron carriers that transport electrons to the electron transport chain. List these two electron carriers. - ATP and FADH - ATP and Acetyl CoA - FADH2 and NADH - ATP and NADH

- FADH2 and NADH

The reaction that converts glucose to two 3-carbon compounds is called: - Chemiosmosis - Electron Transport Chain - Citric acid cycle - Gycolysis

- Gycolysis

Which of the following would be expected in extreme hypoxia? - Low blood lactate and high blood pH - High blood lactate and minimal change to blood pH - Low blood lactate and low blood pH - High blood lactate and low blood pH

- High blood lactate and low blood pH

Which of the following would be expected with poor lactate clearance? - High blood lactate and low blood pH - Low blood lactate and low blood pH - Low blood lactate and high blood pH - High blood lactate and minimal change to blood pH

- High blood lactate and minimal change to blood pH

Why should Kaitlyn be tested for this condition/disease? - Impaired pyruvate metabolism - Impaired lactate clearance - Impaired cardiac lactate shuttle - Impaired oxygen uptake

- Impaired lactate clearance

Activities at steady-state level where ATP demand is met by the mitochondria (exercise at ~35% VO2max) results in: - Greater lactate production compared to highest power output (~250% VO2max) - Increasing production of lactate - Lactate production 15 to 20 fold higher than conversion to acetyl-CoA - Little or no lactate production

- Little or no lactate production

Kaitlyn has high blood lactate (> 2 mmol/L) but minimal change to blood pH. Kaitlyn should be tested for: - Myocardial infarction - Mitochondrial disease - Liver or kidney disease - Hypoxia

- Liver or kidney disease

Which of the following molecules serves as an intermediate electron carrier in the process of respiration? - FAD - ADP - NAD+ - NAD+, FAD, and ATP - NAD+ and FAD

- NAD+ and FAD

During the depolarization phase of an action potential, the permeability of the plasma membrane to: - Na+ decreases - Ca+2 increases - K+ increases - Na+ increases

- Na+ increases

What is considered the final electron acceptor because of its high electronegativity and its role to accept electrons at the end of the electron transport chain? - Electrons - Hydroxide (OH-) - Oyxgen - ATP

- Oyxgen

At higher exercise power outputs, when pyruvate and NADH production exceeds the capability of the mitochondria to metabolize pyruvate, what will be the result? - Production of Acetyl-CoA - Production of Glucose - Production of lactate - Production of Glycolysis

- Production of lactate

Characteristics of P-type ATPases?

- Protein is phosphorylated during the transport process - Transport of ions is against a gradient - The process is "active transport"

When pyruvate production exceeds mitochondrial capabilities to oxidize, which biochemical reaction is favoured? - ATP hydrolysis - Pyruvate reduction by NADH - Lactate catabolism - Phosphocreatine catabolism by creatine kinase

- Pyruvate reduction by NADH

The part of the sarcolemma that folds into the interior of the skeletal muscle cell to increase surface area that an action potential can spread is the: - Sarcoplasmic reticulum - Termical cisternae - T-tubule system - Myofibrils

- T-tubule system

During an action potential, calcium is released into the sarcoplasm, near the actin and myosin molecules. Which of the following is the best explanation of what the calcium does? - The calcium breaks apart ATP to ADP and P - The calcium causes the release of acetylcholine - The calcium removes the tropomyosin block - The calcium binds to the actin and myosin and makes them work together

- The calcium removes the tropomyosin block

List the following biomolecules from greatest potential energy to least potential energy: - Glucose, ATP, triglyceride, H2O, NADH - Triglyceride, glucose, NADH, ATP, H2O - NADH, FAD, ATP, glucose, H2O - Triglyceride, glucose, H2O, FAD, NADH, ATP

- Triglyceride, glucose, NADH, ATP, H2O

How many ATP molecules are formed for each FADH2 that enters the electron transport chain? - Two - Four - One - Three

- Two

Cross bridges form during muscle contraction when myosin comes in contact with active sites on: - calcium ions - tropomyosin molecules - actin molecules - troponin molecules

- actin molecules

During muscle contraction and relaxation, which of these processes require ATP? - Transport of calcium ions into the sarcoplasmic reticulum - release of cross-bridges formation of cross-bridges - active transport of Na+ and K+ ions - all the above

- all the above

Acetylcholinesterase is an important molecule in the neuromuscular junction because it: - stimulates receptors within the postsynaptic membrane - causes the release of Ca2+ from the sarcoplasmic reticulum - breaks down acetylcholine - hsynthesizes acetylcholine from acetic acid and choline

- breaks down acetylcholine

Explain why in anaerobic cells the ratio of pyruvate/ lactate is much less than 1 while under aerobic conditions the ratio of pyruvate/ lactate is much greater than 1. - lactate is produced from pyruvate only under anaerobic conditions - under anaerobic conditions, pyruvate is converted to carbon dioxide - pyruvate is transported into mitochondria under anaerobic conditions - in anaerobic conditions, pyruvate is converted to glucose using the energy of light

- lactate is produced from pyruvate only under anaerobic conditions

At the end of glycolysis, each molecule of glucose has yielded 2 molecules of _______, 2 molecules of _______, and a net of 2 molecules of ______ - CO2, NAD+, ADP - FAD, NAD+, ADP - H2O, CO2, ATP - pyruvate, NADH, ATP

- pyruvate, NADH, ATP

Glycolysis leads to the production of _______ and two molecules of ATP. In the absence of oxygen, fermentation leads to the production of ______. Glycolysis plus the citric acid cycle can convert the carbons of glucose to ______ , storing the energy as ATP, ______ and _______ - glucose, lactic acid, CO2, NADH, FADH2 - lactic acid, pyruvate, CO2, NADH, FADH2 - pyruvate, lactic acid, CO2, NADH, FADH2 - CO2, NADH, FADH2, lactic acid, pyruvate

- pyruvate, lactic acid, CO2, NADH, FADH2

the order that they occur following a single stimulation of a skeletal muscle cell

1) Action potential moves along the T tubules of the muscle cell(s) 2) Sarcoplasmic reticulum releases Ca2+ 3) Ca2+ diffuse into myofibrils 4) Ca2+ binds to troponin 5) Troponin undergoes conformational change moving tropomyosin from myosin-binding sites 6) Myosin heads binds and power strokes cause sarcomeres to shorten 7) Stimulation subsides; sarcoplasmic reticulum takes up Ca2+ (facilitated by SERCA pump) 8) Muscle relaxes

In typical conditions, lactate concentration exceeds lactic acid concentrations True False

True