Sample Exam 1 questions and Poll questions

Negative feedback results in a response that opposes the original deviation from normal.

True

Facilitated diffusion is unable to transport molecules against a concentration gradient.

True

Steroids are derived from cholesterol.

True

Unsaturated fatty acids contain more hydrogen atoms than saturated fatty acids of the same length.

False

All amino acids contain carboxyl and amino groups.

True

The specific shape of a protein determines its function.

True

Glucose enters the cell by the process of facilitated diffusion.

True

At saturation, enzyme activity is minimal.

False

End-product inhibition usually involves allosteric inhibition of an enzyme.

True

The reaction of adenosine diphosphate and phosphate generates adenosine triphosphate and energy.

False

A reducing agent donates electrons to a molecule.

True

Phosphorylation of glucose "traps" the glucose within a cell.

True

Acetyl coenzyme A enables the products of glycolysis to enter the citric acid cycle.

True

Interstitial fluid is made from blood plasma and returns to blood plasma.

True

Active transport proceeds when energy is expended.

True

The glycolysis is responsible for the production of the majority of cellular ATP.

False

The rate of diffusion increases as the concentration gradient increases.

True

The osmotic pressure exerted by a cell would decrease if the cell synthesized more proteins.

False

The molecules responsible for membrane transport are

Proteins

Bonds that are formed between oxygen and hydrogen atoms within water molecules are called

Polar covalent bonds

Which of the following would be most easily broken?

A hydrogen bond

In an acidic solution,

The OH- ion concentration is less than the H+ ion concentration

Which of the following is false regarding unsaturated fatty acids?

All of their hydrogen ions are occupied in double bonds

The base that is NOT found in RNA is

Thymine

Which of the following is NOT a difference between DNA and RNA?

They both can leave the nucleus to perform their functions

A cell which is actively involved in the detoxification of chemicals would contain large quantities of

Peroxisomes

Which of the following statements about enzymes is FALSE?

Enzymes are consumed during a chemical reaction

When an enzyme catalyzes a chemical reaction,

Amino acids in the enzyme's active site interact with substrate molecules to create a product

Addition of phosphate groups to a particular molecule is catalyzed by

Kinases

Anabolic reactions do not

Release energy

Glycolysis converts glucose into two molecules of

Pyruvic acid

To form lactic acid from pyruvic acid it is necessary to have present

NADH

The final electron acceptor in the electron transport chain system is

Oxygen

What theory explains the ability of the electron transport system to pump protons between the inner and outer mitochondrial membranes?

Chemiosmotic theory

The opposite process of glycogenesis is

Glycogenolysis

Which of the following can undergo metabolic conversion to acetyl CoA and enter the citric acid cycle?

All of the choices are correct

A solution consists of a which dissolves the

Solvent dissolves the solute

Osmotic pressure is a measure of the force needed to

Stop osmosis

Facilitated diffusion of a molecule into a cell would be more rapid if the

Concentration of the molecule outside the cell increased

The process that produces the most ATP molecules per molecule of glucose is

Oxidative phosphorylation

The diffusion rate of chemical X across a cell membrane can be increased by

Increasing the area of diffusion

Addition of substrate when enzyme reaction rate is maximal results in

No change in product formation

Anything that prevents ATP formation will most likely

Result in cell death

Choose the statement that accurately describes why catalysts are biologically necessary.

Catalysts make reactions go faster without cellular damage that would occur from heat

Organic acids will contain

a carboxyl group

A membrane that allows only certain molecules to pass through it is called

Selectively permeable

Protein carrier-mediated transport of molecules display

All of the choices are correct

The electron transport system is a series of reactions

Oxidation-reduction

Which of the following types of transport does not require membrane proteins?

Simple diffusion

In a scientific experiment, a control group

Is used for comparison with the experimental group

The first step in the scientific method involves the formation of a(n)

Hypothesis

When an atom loses one or more electrons, it

Becomes positively charged

Hydrophobic molecules would contain bonds

Nonpolar covalent

Molecules that contain carbon and hydrogen atoms are

Organic

The primary structure of proteins is

The linear arrangement of amino acids in the molecule

The "spiral staircase" structure of DNA is referred to as the

Double helix

Folds of the plasma membrane that increase surface area are called

Microvilli

The organelle that acts as enzymes for protein synthesis is the

Ribosome

The function of the is to produce ribosomal RNA.

Nucleolus

Which of the following is NOT a function of the Golgi complex?

Removal of the leader sequence from the protein

A chemical reaction rate can be increased by either the temperature or the activation energy.

Increasing; decreasing

The model that explains how an enzyme and substrate fit together is called the

Lock-and-key model

In an enzymatic reaction, when temperature is increased past the point of "optimal temperature," the enzyme starts to

Reduce its catalytic activity

The final electron acceptor in aerobic cell respiration is

Oxygen

Each turn of the citric acid cycle directly produces molecule(s) of ATP.

One

The yield of ATP from 1 molecule of glucose is

About 38 ATP

What type of tissue is especially dependent on adequate plasma glucose levels?

Nervous

Passive transport of water is known as

Osmosis

Active transport carriers are also called

Pumps

Choose the correct description of the Na+/K+ pump.

It is an example of primary active transport

Secondary active transport

Often utilizes symport proteins

Movement of large molecules into a cell is called

Both endocytosis and bulk transport

The average resting membrane potential of an axon is approximately −70 mV

Ion channels that open in response to depolarization are called

Voltage-gated channels

Which ion's movement is responsible for repolarization?

Outward diffusion of K+

Arrange these steps of the scientific method in
the correct order:
1. Predictions, 2. Hypothesis, 3. Experiment, 4.
Observations.

4,2,1,3

Which of the following best describes homeostasis?

Organisms maintain a narrow range of internal conditions.

Which of the following best illustrates homeostasis?

When the salt concentration of the blood goes up, the
kidneys expel more salt.

Proteins differ from one another because

The sequence of amino acids in the polypeptide chain differs from protein to protein

Fats are composed of

three fatty acids and one glycerol

Which, if any of the following choices, does not properly
pair an organic compound with one of its building blocks
(subunits)?

Nucleic acid – glycerol

Which of the following factors can result in
denaturation of a protein

Answers a, b, and c

Which of these statements about enzymes is true?

None of the above

Enzymes increase the rate of chemical reactions by

Decreasing the activation energy of the reactants

Why does increasing the temperature at some point stops the
activity of an enzyme?

The enzyme will change three-dimensional shape due to
altering tertiary structure

The process that produces the most ATP molecules
per molecule of glucose is

oxidative phosphorylation

Suppose a cell uses 10 moles of glucose for energy
production. No oxygen is available. What will be the
maximum net yield of ATP in moles?

20

Cyanide binds strongly with the last
electron carrier in the chain, preventing
the cell the from using oxygen. How
would this affect the flow of electrons?

The flow would cease and ATP
production would stop.

Red blood cells don’t contain mitochondria. What is their
source of energy?

Glycolysis

What will happen to the volume of red blood cells if they are
placed in a hypotonic solution (solution has lower osmotic
pressure)?

Increase

Which of the following will result in an increase in diffusion rate
across a membrane?

A and B only

The Na/K pump moves Na+ out of the cell, creating a Na+
gradient across the plasma membrane. If a Na+ channel in the
plasma membrane opens, how will the Na+ move through that
channel?

Into the cell by diffusion

Which transport mechanism will a cell use to create a low
concentration of Ca2+ ions in the cytoplasm?

Active Transport

Which of the following best describes what happens during
secondary active transport?

Na+ moves down its concentration gradient and another
molecule moves up its concentration gradient

What kind of solution in bath?

Isotonic

For which ion, Na+ or K+, is the resting membrane potential
further away from its equilibrium?

Na+

If a membrane became more permeable to Na+, what would
happen?

Na+ movement into the cell would cause the membrane
potential to become more positive.

If a neuron is at its resting potential, opening gated Na+
channels will have what effect on the membrane potential?

Depolarization

What stops the
Hodgkin Cycle?

Answers A and C are correct.

Choose the graph below that most closely matches the
membrane response you expect with TTX in your axon recording experiment.

B