Exam 3: Chapters 6, 7, 10, 11

Enzymes are catalyst in reactions. What statements describe functions of enzymes? Select all that apply. - Activity can be affected by temperature - Enzymes lower activation energy needed for a reaction - Once an enzyme binds to a substrate it cannot be used again - Enzymes are specific in their actions - Enzymes change the amount of free energy produced

- Activity can be affected by temperature - Enzymes lower activation energy needed for a reaction - Enzymes are specific in their actions

Which of the following are examples of kinetic energy? Select ALL that apply - Sound - Heat - Concentration Gradients - Energy in Chemical Bonds - Light

- Sound - Heat - Light

The net results of the glycolysis of 2 glucose molecules are... 2 NADH and 4 ATP 2 NADH and 2 ATP 4 NADH and 4 ATP 4 NADH and 2 ATP

4 NADH and 4 ATP

The energy currency used by cells is...

ATP

Phosphofructokinase, is an enzyme used in the first part of glycolysis, that is allosterically inhibited by ATP. This means that...

ATP is able to bind to a site other than the active site of phosphofructoskinase and it's binding there inhibits the activity of phosphofructokinase.

An example (or examples) of potential energy is/are Light Chemical Bonds Light and chemical bonds Chemical bonds and concentration gradients

Chemical bonds and concentration gradients

Energy is stored long-term in the bonds of ______, and used short term to preform work through the use of a(n) _______ molecule

Glucose; ATP

A state of equilibrium is reached when a system as the _____ free energy and the ______ entropy possible.

Highest; lowest

In an animal cell, where does oxidative phosphorylation occur?

In the mitochondria

The energy released when ATP is hydrolyzed to ADP comes from bonds associate with what?

Phosphate Groups

The type of energy held within the bonds if gasoline prior to burning it as fuel is...

Potential Energy

Following the completion of glycolysis, the majority of the energy from glucose remains in what product?

Pyruvate

In a mitochondria, what do the electrons that are added to NAD+ to form NADH ultimately do so that NAD+ can be regenerated? They go to another pathway for ATP production. They energize the entry of the acetyl group into the citric acid cycle. They become part of a fermentation pathway. They are converted to NADP.

They go to another pathway for ATP production.

In the steps of cellular respiration that occur in the mitochondria, what molecules do not cross the mitochondrial cristae? oxygen ATP pyruvate hydrogen ions acetyl-CoA

acetyl-CoA

What is the function of phosphorylation

adds a phosphate group and energy to a molecule

A reducing chemical reaction... reduces the compound to a simpler form removes a hydrogen atom from the substrate. is a catabolic reaction. adds an electron to the substrate.

adds an electron to the substrate.

A molecule of ATP consists of

adenine, ribose, three phosphate groups.

Glycolysis is an ______________ reaction taking place in the ____________ of the cell. anaerobic; mitochondria aerobic; cytoplasm anaerobic; cytoplasm aerobic; mitochondria

anaerobic; cytoplasm

When a compund looses an electron it is said to be what?

oxidized

The energy released by the hydrolysis of ATP does what?

provides energy to coupled reactions

Relative to what is occuring on the right side of this equation, C6H12O6 +6O2---> 6H2O+6CO2 is an example of________ reaction. Anabolic Oxidation dehydration synthesis reduction

reduction or dehydration?

What are some reactants and products in the energy-requiring steps of glycolysis? produces 2 ATP and uses 2 ADP uses 2 ATP and uses 2 ADP produces 4 ATP and uses 4 ADP uses 2 ATP and produces 2 ADP

uses 2 ATP and uses 2 ADP

The net results of the glycolysis of 2 glucose molecules are... 2 NADH and 2 ATP 4 NADH and 4 ATP 2 NADH and 4 ATP 4 NADH and 2 ATP

4 NADH and 4 ATP

List the steps of enzyme functions in order

1.) Active site is open 2.) Substrate binds to active site 3.) Active site will change shape slightly 4.) Substrate is changed into product 5.) Product is released 6.) Active site is available gain

A serving of 30 grams of almond's has 190 calories listed on a nutrition label. This represents enough energy to raise the temperature of...

190 kilograms of water 1C

Substrate-level phosphorylation requires _______ADP (or GDP depending on cell type) molecules to fully oxidize the acetyl-CoA molecules originating from one glucose molecule.

2

By the end of glycolysis, ___________ net ATP and _________ NADH molecules are produced.

2 NADH, 2 ATP

During the citric cycle, _______ NAD+ molecules will be reduced to form NADH from every acetyl-CoA molecule that enters the cycle.

3

The small amount of energy input necessary for all chemical reactions to occur is called the...

Activation Energy

The small amount of energy input necessary for all chemical reactions to occur is called the

Activation Energy (EA)

photosynthesis involving the capture of the kinetic energy from photons of light to drive the synthesis of carbohydrates is an example of...

An endergonic reaction

When a substrate binds to an enzyme, the shape of the active site changes slightly, leading to...

An induced fit shape change

What is an enzyme?

An organic molecule that catalyzed a chemical reaction

6H2O + 6CO2 --> C6H12O6 + 6O2 is an example of

Anabolism

Archaea that make energy without O2 preform

Anaerobic Respiration

What is removed from pyruvate during its conversion into an acetyl group?

CO2

Which of the following is the best way to judge the relative activation energies between two chemical reactions? Compare the Delta G's Compare their reaction rates Compare their ideal environmental conditions Compare the spontaneity between the two reactions

Compare their reaction rates???

Phosphofructokinase-1 (PFK1) catalyzes the conversion of fructose 6-phosphate and ATP to fructose 1,6-bisphosphate and ADP. As shown in the figure below. This action allows for subsequent production of additional ATP molecules in subsequent steps of glycolysis. When ATP levels rise in the vicinity of PFK1, ATP binds to the both the active site and an allosteric site on PFK1 which changes the shape of the active site and prevents the binding of fructose 6-phosphate to the active site. This action prevents further production of fructose 1,6-bisphosphate. Select All that apply. - Decrease in ATP production - Glycolysis inhibition - Increase in ADP production - Decrease in enzyme activity until excess ATP is removed - Denaturing of PFK1

Decrease in subsequent ATP production glycolysis inhibition decrease in enzyme activity until excess ATP is removed

The amount of free energy in a reaction is denoted as

Delta (Triangle) G

The reaction A+B--> C+D has a DG = 100kj/mol; therfore the reaction is - Exergonic - Endergonic

Endergonic because the change in free energy is positive

Which of the following comparisons contrasting endergonic and exergonic reactions is false? Endergonic reactions have a positive DG, and Exergonic reactions have a negative DG Endergonic reactions take place slowly, and exergonic reactions take place quickly Endergonic reactions consume energy and exergonic reactions release energy both endergonic and exergonic reactions require a small amount of energy to overcome an activation barrier

Endergonic reactions consume energy and exergonic reactions release energy

The total energy within a system is known as

Enthalpy

Reactions that have a negative Delta G are known as

Exergonic Reactions

What reactions demonstrate reduction? Select ALL that apply. FAD+ + 2H + 2e-⟶FADH2 O2⟶O2- Fe+2⟶Fe+3 NADH⟶NAD+ + e- + H

FAD+ + 2H + 2e-⟶FADH2 O2⟶O2-

True or False: Enzymes can be used only one time

False

Phosphofructokinase-1 (PFK1) catalyzes the conversion of fructose 6-phosphate and ATP to fructose 1,6-bisphosphate and ADP. As shown in the figure below. When ATP levels rise in the vicinity of PFK1, ATP binds to the both the active site and an allosteric site on PFK1 which changes the shape of the active site and prevents the binding of fructose 6-phosphate to the active site. This action prevents further production of fructose 1,6-bisphosphate. This is an example of... feedback inhibition. competitive inhibition. cofactor inhibition. coenzyme inhibition.

Feedback inhibition

An ATP is converted to an ADP molecule by donating a phosphate group to an intermediate of glucose during glycolysis. Which enzyme catalyzes this reaction?

Kinase

All the chemical reactions that take place inside cells are known as...

Metabolism

For the citric acid cycle to begin, pyruvate must be transported into the...

Mitochondria

Pellagra is a disease caused by a deficiency of nicotinamide, also called vitamin B3 or niacin. What is this substance an important part of? FADH2 NADH and NADPH pyruvate ATP citrate

Not ATP

Which of the following molecules is likely to have the most potential energy -ATP - ADP - Sucrose - Glucose

Sucrose because...

The inorganic phosphate (Pi) that binds to ADP when there is sufficent energy to produce ATP comes from what?

The cytosol

Kinetic energy can be described as energy in motion. Which of the following is not an example of kinetic energy? Heat The energy in chemical bonds sound light random molecular movement

The energy in chemical bonds

substrate-level phosphorylation

The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism.

What statement describes metabolic pathways - Enzymes can determine the products produced based on the substrates available - The product from one reaction will serve as the substrate in the reaction - The same enzyme can be used at each pathway

The product from one reaction will serve as the substrate in the next reaction

Noncompetitive inhibition occurs when?

When a substance binds to an enzyme at a site away from the active site

What is synthesized when oxaloacetate binds to an acetyl group?

citrate (=citric acid)

Scurvy is a disease that presents loss of teeth, hypotension, anemia, and poor wound-healing. These signs and symptoms are caused by a lack of collagen formation. Vitamin C is an organic molecule that temporarily binds to a enzymes involved in the collagen pathway. Based on this information, Vitamin C is important in enzyme function in the collagen pathway because it is a...

coenzyme

Neostigmine is a drug used to treat the disease myasthenia gravis. The drug binds to the active site of acetylcholinesterase preventing breakdown of acetylcholine. This drug is a

competitive inhibitor

Enzymes speed up chemical reactions by

decreasing the activation energy

The dephosphorylation of ATP is an _________________ reaction. endergonic exergonic

exergonic

Coupled reactions occur when

exergonic reactions drive and endergonic reaction

Of the choices given below, which provides the most complete list of the substrates necessary for glycolysis to occur? glucose, protons, ADP, Pi, and NAD+ glucose, protons, ATP, ADP, Pi, NAD+, and pyruvate glucose, protons, ATP, and ADP glucose, protons, ATP, ADP, Pi, and NAD+

glucose, protons, ATP, ADP, Pi, and NAD+

An endergonic reaction is a reaction that is characterized by

having higher energy in product molecules than the reactants, and often yielding larger product molecules

Which statements about metabolism is/are true? i. Metabolism includes catabolism and anabolism ii. Metabolism included non catalyzed enzyme reactions iii. Metabolism is the set of life-sustaining chemical transformations within the cell of living organisms

i. and iii.

Consider a pendulum swinging. Which types of energy are associated with the pendulum in the following instances i. The moment at which it comes full cycle, just before it begins to fall back towards the other end ii. The moment that it is in the middle between the two ends iii. Just before it reaches the end of one cycle (just before instant i)

i. potential, ii. kinetic, iii. potential and kinetic

Which of the following is not true about enzymes - Each one is specific to a particular substrate - Made of amino acids -Lower activation energy of chemical reactions - Increase DG of reactions

increase DG of reactions

An important step in glycolysis is the conversion of glucose-6-phosphate into fructose-6-phosphate by a(n): kinase isomerase structurase phosphatase

isomerase