Transcript What type of electron is available to form bonds?

1. What type of electron is available
to form bonds?
a.
b.
c.
d.
valence
nucleus
ionic
covalent
Chemical Bonds
• Chemical Bonds
• The atoms in compounds are held
together by chemical bonds.
• Bond formation involves the
electrons that surround each atomic
nucleus.
• The electrons that are available to
form bonds are called valence
electrons.
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2. Amino acid is to protein as
a.
b.
c.
d.
fat is to lipid.
sugar is to fat.
DNA is to RNA.
simple sugar is to starch.
4. Proteins
Proteins are macromolecules that
contain nitrogen, carbon, hydrogen,
and oxygen.
Proteins are polymers of molecules
called amino acids.
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3. Which of the following is NOT a
function of proteins?
a. store and transmit genetic
information
b. help to fight disease
c. control the rate of reactions and
regulate cell processes
d. build tissues such as bone and
muscle
Some proteins control the rate of
reactions and regulate cell processes.
Some proteins are used to form
bones and muscles.
Other proteins transport substances
into or out of cells or help to fight
disease.
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4. Which statement is true?
a. Simple sugars are made of
polysaccharides.
b. Glycerol is made of fatty acids.
c. RNA molecules are made of
nucleotides.
d. Amino acids are made of
proteins.
What is their function?
Nucleic acids store and transmit
hereditary, or genetic, information.
There are two kinds of nucleic acids,
ribonucleic acid (RNA) and
deoxyribonucleic acid (DNA).
RNA contains the sugar ribose.
DNA contains the sugar deoxyribose.
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5. What is the process that changes
one set of chemicals into another
set of chemicals?
a.
b.
c.
d.
cohesion
chemical reaction
adhesion
dissolving
Chemical Reactions
A chemical reaction is a process that
changes one set of chemicals into
another set of chemicals.
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6. What is the term used to describe
the energy needed to get a reaction
started?
a.
b.
c.
d.
adhesion energy
cohesion energy
activation energy
chemical energy
Activation Energy
Sometimes spontaneous reactions
need help getting started.
Chemists call the energy that is
needed to get a reaction started the
activation energy.
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7. Chemical reactions that release
energy
a.
b.
c.
d.
will not occur.
will always explode.
will never explode.
often occur spontaneously.
Energy Changes
Chemical reactions that release
energy often occur spontaneously.
Chemical reactions that absorb
energy will not occur without a
source of energy.
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8. If a reaction in one direction
releases energy, the reaction in the
opposite direction
a.
b.
c.
d.
also releases energy.
destroys energy.
absorbs energy.
cannot occur.
Chemical reactions always involve changes in the
chemical bonds that join atoms in compounds.
Energy in Reactions
Energy is released or
absorbed whenever
chemical bonds form or
are broken.
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9. Which of the following is a form
of energy that may be released
during a chemical reaction?
a.
c.
b.
d.
heat
light
sound
all of the above
Energy in Reactions
Energy is released or
absorbed whenever
chemical bonds form or
are broken.
Released energy can be:
-Heat
-Light
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-Sound
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10. Which of the following
statements about enzymes is NOT
true?
a. Enzymes work best at a
specified pH.
b. All enzymes have the same
shape as their substrates.
c. Enzymes are proteins.
d. The shape of an enzyme allows
it to do its job.
The Enzyme-Substrate Complex
Enzymes provide a site where
reactants can be brought together
to react, reducing activation
energy.
The reactants of enzymecatalyzed reactions are known as
substrates.
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11. A substance that accelerates the
rate of a chemical reaction is called
a(an)
a.
b.
c.
d.
catalyst.
molecule.
lipid.
element.
So what is a catalyst?
• A substance that brings about a reaction without
being changed itself.
Catalysts work by
lowering a
reaction's
activation energy.
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12. Enzymes affect the reactions in
living cells by changing the
a.
c.
b.
d.
products of the reaction.
temperature of the reaction.
speed of the reaction.
pH of the reaction.
How enzymes work
•
•
•
•
Depends on shape.
Substrate fits into active site.
Substrate must be the right shape.
Enzyme weakens substrate bonds so reaction
can take place.
• They speed up reactions.
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You can have lunch now.