Biochemistry Study
Guide
Plants and animals are composed of
organic compounds. Which of the
following are the common elements
found in organic compounds?
• SPONCH
• Sulfur, phosphorus, oxygen, nitrogen, carbon,
hydrogen
Which of the following
compounds is most likely to be
part of living organisms?
C6H12O6, BF3, MoCl2, CsI
• C6H12O6
Which of the following elements is
best able to combine with itself and
hydrogen (H) to form large
molecules?
Sodium (Na), Lithium (Li), Sulfur
(S), Carbon (C )
Carbon
The table below shows the
elemental composition of 3 different
types of organisms
The X in the table represents which
element?
• Nitrogen
What characteristics of carbon
(C ) makes it essential to living
organisms?
• Carbon can bond with itself in many ways to
form chains
The structure of an organic
molecule is represented below
In this organic molecule, which
element is identified by each X?
• Carbon
Although there are a limited
number of amino acids, how
can we make different types of
proteins?
• Different proteins have different numbers of
amino acids in different orders
A diagram of a protein molecule is
shown above. The units labeled “X”
which bond together to form the
protein molecule are called _______
• Amino Acids
The clear protein of an egg
white becomes opaque and
firm when cooked because the
heat
• Changes the structure of the protein
Proteins are large
macromolecules composed of
thousands of subunits. The
structure of the protein
depends on the sequence of
• Amino Acids
Which molecule is correctly paired with
the class of molecule to which it belongs
Lactose – lipid
Collagen – protein
Hemoglobin – carbohydrate
Hydrochloric acid – nucleic acid
• Collagen - Protein
A chart listing the characteristics of
4 macromolecules is shown below
Which molecule listed in the chart is
a protein?
• Number 4
• Because the monomer is an amino acid
Ovalbumin is a protein found
in eggs. What is the molecular
structure of ovalbumin?
• Chain of amino acids folded and twisted into a
molecule
Which of the following categories of organic
molecules is correctly paired with one of its
functions?
Nucleic acids – digest dead cells
Lipids – give quick energy to cells
Carbohydrates – store genetic information
Proteins – provide structure in skin, hair,
and nails
• Proteins – provide structure in skin, hair and
nails
What is the relationship that
exists among proteins, DNA
and cells?
• Cells contain DNA, which controls the production
of proteins
What is the role of an enzyme
in a chemical reaction?
• It provides the activation energy of the reaction
There are many different
enzymes located in the
cytoplasm of a single cell. How
is a specific enzyme able to
catalyze a specific reaction?
• An enzyme binds to a specific substrate for the
reaction to be catalyzed
In red blood cells, the compound
carbonic anhydrase increases the rate
at which carbon dioxide is converted to
bicarbonate ions for transport in the
blood. In red blood cells, carbonic
anhydrase acts as a ___________
• An enzyme
Individuals who lack lactase
are unable to break down the
sugar lactose. What is lactase?
• An enzyme = lactase
• Lactose = substrate
In the diagram above, the
substance labeled X is ________
• An enzyme
The figure below shows the reaction rate
of a specific enzyme at different
temperatures and different pHs.
What can be concluded about the
enzyme?
• The enzyme works best at a pH of 8 and a
temperature of 25C
The illustration below shows a Siamese cat.
In Siamese cats, an enzyme determines the
color of the fur. On the cooler places of the
body, the enzyme causes darker fur. On the
warmer parts of the body, the enzyme does
not function.
How does temperature affect this enzyme?
• The enzyme is active in a specific temperature
range
Why are enzymes necessary
for many cellular reactions?
• The reactions are too slow to meet the needs of
the cell if enzymes are missing
The diagram below shows the final steps of a biochemical
pathway used by the bacterium Serratic marcescens to produce
a red pigment molecule. Letters X, Y, Z represent intermediate
molecules produced in the pathway. 4 enzymes are also
involved in the pathway, as shown.
A mutant strain of S. marcescens produces molecules X and Y
but does not produce the red pigment molecule or molecule Z.
Based on this result, it can be concluded that there must be a
mutation in the gene coding for which enzyme?
• Enzyme 3
The reaction catalyzed by the bacterial enzyme B-galactosidase
forms a dark-colored end-product when the cells are grown on
a particular agar medium. As more product is formed, the cells
become darker.
Students performed an experiment to determine the optimum
pH for activity of this enzyme. Their results are shown in the
illustration of bacterial colonies below
Based on these data, the students should conclude that Bgalactosidase functions best at which pH?
• pH7
The structural form of cellulose is
shown
What type of macromolecule
describes cellulose?
• Carbohydrate.
Carbohydrates are macromolecules used for
energy in living organisms. Large
carbohydrate molecules are made of smaller
building blocks called monosaccharides.
The arrangement of which 3 components is
used to distinguish one monosaccharide from
another?
• CHO
• Carbon, hydrogen, oxygen
What is the primary function of
carbohydrates?
• Storage of energy
The characteristics listed below can be used to
describe some molecules
-Inorganic
-Supplies energy and fiber
-Component of plant cell walls
-Part of DNA
-Made of nucleotides
Which of these characteristics describe a
carbohydrate?
• Supplies energy and fiber
• Component of plant cell walls
• Part of DNA
The table below provides
information about the composition
and function of 4 important
molecules in living organisms
Which is a carbohydrate?
•3
What do disaccharides, such
as sucrose, and
polysaccharides, such as
starch, have in common?
• They are carbohydrates made of simple sugars
What is a main reason humans
need to include carbohydrates
in their diet?
• Carbohydrates are broken down in cells for
energy
Carbohydrates and proteins
are 2 types of macromolecules.
Which functional characteristic
of proteins distinguishes them
from carbohydrates?
• Proteins are able to catalyze biochemical
reactions
Many aquatic birds secrete waxy organic
substances that repel water. The birds
use these substances to coat their
feathers. An analysis of these substances
would reveal that they are composed
mostly of
• Lipids
The diagram below represents a fat
molecule
A fat molecule belongs to which
category of organic molecules?
• Lipids
Which type of molecule in the
yolk of a chicken egg provides
the most energy for a
developing chick?
• Lipid
The brown paper test for lipids is
positive when food is placed on the
paper and a spot forms which will allow
light to pass through it. What is a food
that would give you a positive test for
lipids?
• Potato chips
One category of organic compounds
contains molecules composed of long
hydrocarbon chains. The hydrocarbon
chains may be saturated or
unsaturated.
Which category of organic compounds
contains these molecules?
• Lipids
Which group of organic
compounds contains fatty
acids?
• Lipids
Lemur’s bodies are adapted to efficiently store
energy for times when food is scarce. This
adaptation may help to explain how lemur
ancestors survived the trip across the
Mozambique Channel from mainland Africa
to Madagascar.
Which type of molecule is primarily used for
long-term energy storage in the lemur?
• Lipids
What is the composition of a
nucleotide?
• A 5 carbon sugar attached to a phosphate group
and a nitrogenous base
What is the role of ATP in
animal cells?
• ATP stores and releases energy
A protein in a cell membrane changed
its shape to move sodium and potassium
ions against their concentration
gradients. Which molecule is most likely
used by the protein as an energy source?
• ATP
What is a DNA molecule made
of?
• It is made of nucleotides and has a double
helix shape
An iodine solution is placed on
the cut side of a potato. Within
seconds, a blue-black color
appears. What is this a positive
test for?
• Starches
What structure is most
responsible for maintaining
homeostasis in a cell?
• Cell membrane
Which cycle is this picture
likely illustrating?
• Carbon cycle