MCAT FC5 CC5E

What is the heat energy required to completely vaporize 10 g of water beginning at 0°C? (The heat capacity of water is 4.2 J/g·K and the ΔH_vaporization of water is 2260 kJ/kg

-26.8 kJ -using q=mcat

Which of the following will be true regarding enzymes saturated with substrate?

-An enzyme with lower K_m is more easily saturated than an enzyme with high K_m

Which of the following scenarios violates the first law of thermodynamics, "the conservation of energy?"

-An isolated electrochemical cell that indefinitely generates an electrical current.

A hot object is placed next to a cold object so that they are touching. Which of the following statements is true? I. Heat will transfer from the hot object to the cold object because the hot object has a higher temperature.II. The two objects are in thermal equilibriumIII. Internal energy will transfer from the hot object to the cold object because the hot object has greater internal energy.

-I only

Which of the following is true concerning the induced fit model of enzyme catalysis?

-The active site can be influenced by molecules binding elsewhere on an enzyme

Equal amounts of heat are absorbed by 100 g samples of various solid metals with differing specific heat values. Which of the following statements is true regarding metals and their specific heat values?

-The metal with the greatest specific heat will undergo the smallest change in temperature.

If an enzyme functions to enable the following reaction, which type of catalytic strategy is most likely, given the chemical reaction shown? (OH --> H + O)

-acid/base catalysis

Potassium cyanide is a poison which combines with cytochrome a_3 to prevent binding of oxygen to the enzyme without altering the K_m of the reaction with respect to reduced cytochrome c. Which type of inhibition does this represent?

-noncompetitive

Additional gas is pumped inside a rigid container that stores compressed gas. Which of the following is a true statement about this system?

-there is no work done on the container

Which of the following enzyme classes catalyze reactions in which two molecules are covalently connected to each other?

-ligase

Which of the following is true of enzymes? I. They increase the rate of reaction by stabilizing the transition stateII. They raise activation energy to shift the equilibrium to favor the productsIII. They lower activation energy by altering the products of a reaction

-I only

With regards to the Michaelis-Menten equation, a molecule that has the effect of increasing the Vmax of a reaction upon binding to an enzyme would be called what?

-activator

In the first step of glycolysis, hexokinase produces glucose-6-phosphate. G-6-P itself can also bind to hexokinase at the active site, blocking access to ATP. This is an example of:

-feedback inhibition

S-Adenosyl methionine (SAM) is a molecule utilized in various metabolic pathways to transfer methyl groups from SAM to an acceptor. What is the proper designation of the complex of SAM and its enzyme together?

-holoenzyme -which is the complex of an enzyme that has its cofactor bound and is considered 'complete'

In a system undergoing adiabatic compression, what are the values of internal energy and heat if work done on the system is 500 J?

-internal energy is 500 J and heat is 0 J -because adiabatic process means q=0

Atmospheric gases absorb more energy than they emit. If we consider a gas to be a closed system, which of the following is true?

-the heat absorbed by the gas is positive

When heating a solution, a scientist detects a temperature increase in the solution during a period of time. Which of the following statements accurately characterizes the solution during this period?

-the velocity of molecules in the solution is increasing