Download Name: ____________ Pd.: ______ Date: Read Section 2.1 – Atoms

Name: _____________________________________________________ Pd.: ________ Date: ______________________
Study Guide – Biochemistry, Part I
Read Section 2.1 – Atoms, Ions, and Molecules, and answer the following questions:
1. _________________: The smallest basic unit of matter
2. Atoms consist of three types of smaller particles, called subatomic particles. They are:
____________________ - positive charge
____________________ - neutral charge
____________________ - negative charge
3. The nucleus of an atom is made up of the ______________ and ______________.
4. Because an atom has equal numbers of positively charged _____________ and negatively charged
_______________, it is electrically neutral.
5. _________________: One particular type of atom which cannot be broken down into a simpler substance by
ordinary chemical means. It also refers to a group of atoms of the same type.
6. Atoms of different elements differ in the number of ______________ they have.
7. The chemical properties of an element are determined by the __________________.
8. Electrons move around the nucleus of an atom in regions called energy levels. Different energy levels can
hold different numbers of electrons. The first energy level can hold ___________ electrons, and the second
energy level can hold ___________ electrons. Atoms are most stable when they have a full outermost
energy level.
9. The four elements that make up 96 percent of the human body’s mass are
______________________
______________________
______________________
______________________
10. Elements found in very small amounts in the body but which are needed to survive are called
______________ elements. For example, iron (Fe) is needed to transport oxygen in your blood. Chromium
(Cr) is needed for your cells to break down sugars for usable energy.
11. ___________________: A substance made of atoms of different elements bonded together in a certain
ratio.
12. ___________________: An atom that has gained or lost one or more electrons.
13. ___________________: A bond formed through the electrical force between oppositely charged ions.
14. ___________________: A bond formed when atoms share a pair of electrons. These bonds are generally
very strong.
15. ___________________: Two or more atoms held together by covalent bonds
Read Section 2.2 – Properties of Water, and answer the following questions:
16. Unlike most substances, water ________________ as it freezes. Water is therefore [less] [more] dense as a
solid (ice) than as a liquid.
17. Water molecules have a region with a slight positive charge and a region with a slight negative charge. This
water a ________________ molecule.
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18. Opposite charges of polar molecules can interact to form ______________ bonds. These bonds are an
attraction between a slightly positive hydrogen atom and a slightly negative atom, often oxygen or nitrogen.
19. Hydrogen bonds are responsible for three important properties of water:
STUDY GUIDE – BIOCHEMISTRY, PART II
Section 2.3
1. All organic compounds contain the element ___________________.
2. Circle the item below which is NOT an organic macromolecule:
Carbohydrate
ice
lipid
nucleic acid
3. Identify each of the following as primarily a carbohydrate, lipid, protein, or nucleic acid.
_________________ Sugars
__________________ DNA
__________________ waxes
__________________ meat
__________________ bread
__________________ RNA
__________________ cholesterol
__________________ fats
4. The two types of nucleic acids are _________________ and _________________.
5. Which type of organic biological macromolecule do each of the following food products primarily contain:
____________________
______________
_________________
_________________
6. Circle the item below which is NOT a lipid:
Saturated fats
starch
cholesterol
earwax
7. A typical can of soda contains a large amount of sugar. Therefore, sodas are high in _________________________.
8. An athlete who wants to build muscle mass would most likely choose a diet high in __________________________.
9. An athlete preparing to run a long-distance marathon would most likely choose a meal before the event that was high
in ______________________.
10. Name the macromolecule that is composed of each of the following subunits:
Amino acids ____________________________
Sugar molecules _________________________
Fatty acids _____________________________
Nucleotides_____________________________
The molecule shown here is a
monomer of one of the four
biological macromolecules. It
is a(n)
_____________ _________
Starches _______________________________
11. The diagram to the left is a monomer of ____________________.
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Section 2.4
12. Substances are changed into different substances by ___________________________________.
13. Which organic biological macromolecule is the main source of energy for living things? ________________________.
14. Which biological macromolecule is responsible for the genetic inheritance of physical traits? ___________________
15. Identify the reactants in the following chemical reaction: 6H 2O + 6CO2
C6H12O6 + 6O2
__________________________________
Identify the products of the above chemical reaction: __________________________________________
16. What is the term for the amount of energy that needs to be added for a chemical reaction to start?
________________________________________
17. Match the following terms:
a. exothermic reaction
____ the subunit of a polymer
b. endothermic reaction
____ large compound formed by the joining of small compounds (monomers)
c. catalyst
____ substance that decreases activation energy and increases reaction rate
d. activation energy
____ energy input necessary to start a chemical reaction
e. enzyme
____ a protein that catalyzes (speeds up) chemical reactions for organisms
f. chemical reaction
____ process that produces a new set of chemicals
g. monomer
____ a chemical reaction that absorbs energy
h. polymer
____ a chemical reaction that releases energy
Section 2.5
18. Which statement best describes the graph shown here?
a. more energy is released by the original reaction
b. less energy is needed to start reaction B
c. the original reaction is catalyzed
d. reaction B occurs at a slower rate
A ____________________
B _______________________
19. Label each of the diagrams above as an exothermic or endothermic reaction.
20. What does the letter “B” represent in each of the diagrams? ___________________________
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21. In each of the diagrams above, the letter “A” represents the _____________________ of the chemical reaction and
the letter “B” represents the ________________ of the chemical reaction.
22. In the diagram of a chemical reaction to the left, which reaction pathway
requires the least activation energy? _________
23. Most enzymes are
a. carbohydrates
b. lipids
c. nucleic acids
d. proteins
24. Enzymes affect chemical reactions in living organisms by
a. changing the direction of a reaction
b. breaking down molecules into starch
c. increasing the temperature range
d. weakening bonds in all reactants
25. The specific reactants that an enzyme acts on are called
a. catalysts
b. proteins
c. substrates
d. amino acids
26. Changes in temperature and pH can decrease an enzyme’s activity by breaking
a. hydrogen bonds
b. peptide bonds
c. amino acids
d. sulfur-sulfur bonds
27. An animal’s stomach contains enzymes that break down food into smaller molecules that the animal’s cells can use.
Enzymes perform this function by
a. participating in chemical reactions
b. increasing the temperatuire
c. changing the ionic concentration
d. lowering the pH
28. Match the following terms:
a. amino acid
____ dissolved compound that prevents sharp swings in pH
b. monosaccharide
____ atoms of the same element that differ in the number of neutrons
c. isotopes
____ monomer of a protein
d. buffer
____ the reactant in a chemical reaction upon which an enzyme acts
e. nucleic acid
____ single sugar molecule
f. bond energy
____ the amount of energy needed to break a bond
g. substrate
____ stores and transmits genetic information
h. equilibrium
____ a condition in which reactants and products in a chemical reaction are formed at
the same rate
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