Enzyme Catalysis and Reaction Rate Quiz

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What is the catalytic strategy used by carbonic anhydrases?

Acid-Base Catalysis

Charge Complementarity

Covalent Catalysis

Approximation (correct)

What metal ion is universally used in the family prevalence of carbonic anhydrases?

Zinc (correct)

Cadmium

Cobalt

Iron

How many families of carbonic anhydrases have been discovered?

5

10

15

8 (correct)

What is the main physiological relevance of carbonic anhydrases?

pH regulation Signup and view all the answers

Which enzyme utilizes the catalytic strategy of Approximation?

Carbonic Anhydrase Signup and view all the answers

What is the steady state assumption?

The formation of the E·S complex occurs at the same rate as its loss Signup and view all the answers

What does the equilibrium constant Km represent?

The concentration of substrate needed to achieve half the maximum reaction rate Signup and view all the answers

In the equation Δ𝐸·𝑆 = 𝑘1 𝐸 𝑆 − 𝑘−1 𝐸·𝑆 − 𝑘2 𝐸·𝑆 = 0, what does Δ𝐸·𝑆 represent?

Change in the concentration of substrate-bound enzyme Signup and view all the answers

How does knowing [E]T and [E·S] help in understanding enzyme kinetics?

It enables determination of the rate of product formation Signup and view all the answers

What correction factor can be used to correct for osmolarity deviations?

Osmotic coefficient Signup and view all the answers

What is the main contributor to the osmolarity of the interstitial fluid and plasma?

NaCl ions Signup and view all the answers

What causes the slight difference between plasma and interstitial fluid osmolarity?

Osmotic effects of plasma proteins Signup and view all the answers

What maintains about 20 mm Hg greater pressure in the capillaries than in the surrounding interstitial spaces?

Plasma proteins Signup and view all the answers

What can cause a slight decrease in the osmotic activity of dissolved substances?

Interionic attraction Signup and view all the answers

What happens with small changes in the concentration of solutes in the extracellular fluid?

High osmotic pressures develop across the cell membrane Signup and view all the answers

About how much of the total osmolarity of intracellular fluid is due to potassium ions?

Half Signup and view all the answers

What is used to express corrected osmolar activities of plasma, interstitial fluid, and intracellular fluid?

(mOsm/L) Signup and view all the answers

What effect does urea have on intracellular volume under steady-state conditions?

It has little effect on intracellular volume Signup and view all the answers

Why is complete osmotic equilibrium not immediately achieved between the intracellular and extracellular compartments throughout the whole body?

Fluid needs to be transported by the blood to all tissues before equilibrium can occur Signup and view all the answers

What are some factors that can cause extracellular and intracellular volumes to change?

All of the above Signup and view all the answers

What is the timeframe within which differences in osmolarities between intracellular and extracellular compartments are usually corrected?

Minutes Signup and view all the answers

How does the transfer of fluid across the cell membrane contribute to the correction of differences in osmolarities?

It occurs rapidly, allowing for quick correction Signup and view all the answers

What is the primary reason for the delay in achieving complete osmotic equilibrium between the intracellular and extracellular compartments?

Fluid needs to be transported by the blood to all tissues Signup and view all the answers

What happens to the concentrations of highly permeating substances like urea in the intracellular and extracellular fluids over time?

They eventually become equal in the two compartments Signup and view all the answers

What is the immediate effect of highly permeating substances like urea on fluid volume between intracellular and extracellular fluids?

They cause transient shifts in fluid volume between the two compartments Signup and view all the answers

What is the relationship between pH and H+ concentration?

pH is inversely related to H+ concentration Signup and view all the answers

What is the normal pH of arterial blood?

7.4 Signup and view all the answers

At what pH would a person be considered to have acidemia?

Below 6.8 Signup and view all the answers

Why is it customary to express H+ concentration on a logarithm scale using pH units?

Because small numbers are cumbersome Signup and view all the answers

What would a high pH correspond to in terms of H+ concentration?

Low H+ concentration Signup and view all the answers

What is the pH of venous blood and interstitial fluids?

7.35 Signup and view all the answers

What does a low pH correspond to in terms of H+ concentration?

High H+ concentration Signup and view all the answers

What does the formula pH=-log[H+] indicate about the relationship between pH and H+ concentration?

-log[H+] has an inverse relationship with pH Signup and view all the answers

What is the primary purpose of the body fluid buffers?

To neutralize the acids produced by the body Signup and view all the answers

What is the bicarbonate buffer system composed of?

A weak acid and a bicarbonate salt Signup and view all the answers

Where is carbonic anhydrase especially abundant in the body?

In the walls of the lung alveoli Signup and view all the answers

What happens to the daily production and ingestion of acids without buffering?

It causes lethal changes in the body fluid H+ concentration Signup and view all the answers

What is required for the formation of H2CO3 in the body?

Presence of carbonic anhydrase Signup and view all the answers

Which buffer system is quantitatively most important in the extracellular fluid?

Bicarbonate buffer system Signup and view all the answers

What does ingestion or production of about 80 milliequivalents of H+ each day by metabolism imply?

The body has efficient buffering mechanisms Signup and view all the answers

What happens to the H2CO3 formation if carbonic anhydrase is absent?

No formation of H2CO3 occurs Signup and view all the answers