Introduction and Chemistry

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Introduction and Chemistry
 

True/False
Indicate whether the statement is true or false.
 1.
The study of biology can help you better understand human reproduction.
 2.
Almost all organisms ultimately get their energy for survival from the sun.
 3.
All living things are composed of chemicals.
      nar001-1.jpg      nar001-2.jpg
 4.
Refer to the illustration above. Both species are multicellular.
 5.
Refer to the illustration above. Both species have DNA in their cells.
 6.
Refer to the illustration above. Reproduction ensures the ongoing success of both species.
 7.
Refer to the illustration above. The sand dollar and paramecium both show organization.
 8.
Refer to the illustration above. Unlike the sand dollar, the paramecium does not have to maintain a stable internal environment.
 9.
Scientists have not discovered any new species on Earth in more than 20 years.
 10.
A scientist who performs an experiment has no idea what the outcome of the experiment is going to be.
 11.
A theory is a hypothesis that has been proven true.
 12.
A theory is an assumption made by scientists and implies a lack of certainty.
 13.
Publication of the results of scientific investigations enables other scientists to verify these results.
 14.
Scientific investigations always follow a series of rigidly defined steps.
 15.
Resolution is a microscope’s power to increase an object’s apparent size.
 16.
The resolution power of an electron microscope is limited by the physical characteristics of light.
 17.
Units of time are not measured in metric units, so time measurements are not accepted for use with SI units.
 18.
The types of particles that are located in the nucleus of an atom are protons and neutrons, and the types of particles that are located in the energy levels surrounding the nucleus are electrons.
 19.
The atomic number of carbon is 6, so it must contain 12 electrons.
 20.
Most elements are stable if their outermost energy level contains an even number of electrons.
 21.
Atoms in a gas move more rapidly than atoms in a liquid or a solid do.
 22.
The products of an endergonic chemical reaction possess more energy than the reactants from which they are produced.
 23.
The amount of energy needed to cause a chemical reaction to start is called activation energy.
 24.
When an enzyme binds with its substrate, the activation energy needed for the chemical reaction to occur is raised.
 25.
Enzymes speed up a chemical reaction by increasing the activation energy of the reaction.
 26.
Without enzymes, chemical reactions necessary for life would not occur at a rate sufficient to sustain life.
 27.
Free hydrogen ions can react with water molecules and form a positively charged ion, the hydronium ion.
 28.
Bases tend to have a sour taste, while acids tend to have a bitter taste.
 29.
Buffers can neutralize acids, but they do not affect bases.
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 30.
Biology is the study of
a.
minerals.
c.
the weather.
b.
life.
d.
energy.
 31.
Instructions for development that are passed from parents to offspring are known as
a.
a species plan.
c.
genes.
b.
organ codes.
d.
natural selections.
 32.
Homeostasis means
a.
a change over long periods of time.
c.
rapid change.
b.
keeping things the same.
d.
the same thing as evolution.
 33.
Which of the following is a means by which heterotrophs can obtain energy?
a.
using water, carbon dioxide, and energy from the sun to produce sugars
b.
using water and carbon dioxide to produce energy-rich compounds
c.
consuming autotrophs
d.
consuming simple chemicals from the environment and using them to assemble complex chemicals and structures needed by the organism
 34.
Which of the following is not necessarily a distinct property of living things?
a.
homeostasis
c.
complexity
b.
metabolism
d.
reproduction
 35.
All organisms are composed of
a.
diatoms.
c.
cells.
b.
cellulose.
d.
None of the above
 36.
Scientific hypotheses are most often tested by the process of
a.
communicating.
c.
experimenting.
b.
inferring.
d.
analyzing data.
 37.
A unifying explanation for a broad range of observations is a
a.
hypothesis.
c.
prediction.
b.
theory.
d.
controlled experiment.
 38.
Most typically, the order in which the steps of the scientific method are applied is
a.
observations, predictions, hypothesis, controlled testing, theory, verification.
b.
predictions, observations, hypothesis, theory, controlled testing, verification.
c.
observations, hypothesis, predictions, controlled testing, theory, verification.
d.
observations, hypothesis, predictions, controlled testing, verification, theory.
 39.
Atoms are composed of
a.
protons with a positive charge.
c.
electrons with a negative charge.
b.
neutrons with no charge.
d.
All of the above
 40.
Which of the following states of matter contain(s) particles that are tightly linked together in a definite shape?
a.
solid
c.
gas
b.
liquid
d.
solid and liquid
 41.
The bond formed when two atoms share a pair of electrons is called a
a.
hydrogen bond.
c.
covalent bond.
b.
nonpolar bond.
d.
water bond.
 42.
An atom that has gained or lost electrons is called a(n)
a.
molecule.
c.
ion.
b.
nucleon.
d.
element.
 43.
Which of the following statements most accurately describes the difference between an ionic bond and a covalent bond?
a.
Atoms held together by ionic bonds separate when placed in water while atoms held together by covalent bonds do not separate in water.
b.
Ionic bonds hold together atoms of two different types, while covalent bonds hold together atoms of the same type.
c.
Electrons are exchanged between atoms held together by an ionic bond, but they are shared between atoms held together by a covalent bond.
d.
Ionic bonds form between atoms that carry opposite charges, while covalent bonds form between uncharged atoms.
 44.
A reaction in which the products have less energy than the reactants is
a.
an endergonic reaction.
c.
a filamentous reaction.
b.
an exergonic reaction.
d.
impossible.
nar002-1.jpg
 45.
Refer to the graph above. Which of these statements is true regarding the graph?
a.
Reaction “2” occurs faster than Reaction “3” because Reaction “2” requires more energy than Reaction “3.”
b.
The difference in the graphs shown for Reaction “2” and Reaction “3” is due to a difference in the activation energy needed for these reactions.
c.
Reactant “A” contains more energy at the beginning of the reaction than Product “C” has after the reaction.
d.
All of the above
nar003-1.jpg
 46.
Refer to the graphs above. Which graph illustrates what happens during an exergonic reaction?
a.
Graph “A”
b.
Graph “B”
c.
Both graphs; they each show a different stage of an exergonic reaction.
d.
Neither graph shows an exergonic reaction.
 47.
Refer to the graphs above. Which graph illustrates a reaction during which reaction energy is released into the environment?
a.
Graph “A”
b.
Graph “B”
c.
Both graphs, since all chemical reactions release energy into the environment
d.
Neither graph, since chemical reactions do not involve energy
 48.
Enzymes
a.
are able to heat up molecules so that they can react.
b.
provide CO2 for chemical reactions.
c.
are biological catalysts.
d.
absorb excess heat so that reactions occur at low temperatures.
 49.
A neutral solution has an equal number of
a.
hydrogen and hydronium ions.
c.
hydrogen and hydroxide ions.
b.
hydroxide and hydronium ions.
d.
oxygen and hydrogen ions.
 50.
Buffers
a.
are of relatively little importance in living things.
b.
are formed when a large number of hydroxide ions are released in a solution.
c.
are formed when a large number of hydronium ions are released in a solution.
d.
tend to prevent great fluctuations in pH.

 

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