U1 Test Review (V2) KEY: Scientific Processes, Biomolecules, and Enzymes
I. Biomolecules
Biomolecules are carbon-based macromolecules formed by joining repeating subunits called monomers. They form the basis of all
living things. Refer to pages 167-171 and view the charts below for specific information about each biomolecule.
II. Enzymes
Enzymes are a type of protein that acts like a catalyst, which speeds up chemical reactions. In the diagram below, refer to
page 160, Figure 18, of your Biology textbook and label the parts of the enzyme reaction. Describe what is occurring in
each step.
1. Label the
enzyme and
the substrate.
3. Label the image
and describe the
reaction.
2. Label the image
and describe the
reaction.
2. Reaction description:
Substrate (reactants) attached to active
site of the enzyme and forms
enzyme-substrate complex.
3. Reaction description:
Substrates (reactants) become
products and are released from the
enzyme, which can be used again.
Enzymes are specific. Amylase breaks down starch (a carbohydrate); Protease breaks down proteins; and Lipase
breaks down lipids. Enzymes work by reducing the amount of activation energy needed to complete a reaction.
In the diagram below, label which line uses an enzyme and which line does not use an enzyme. Refer to page 159,
Figure 17 to help with labeling the diagram below.
Line A
Line A: Reaction that does not include an enzyme, and the solid
red line represents the amount of energy required to activate the
reaction.
Line B
Line B: Reaction that includes an enzyme, and the dotted red line
represents the amount of energy required to activate the reaction.
Notice this reaction requires less energy because an enzyme is used.
List factors that can affect how fast enzymes
can work, and explain how this is related to
denaturing of the protein.
Factors such as pH, temperature, enzyme
concentration and the presence of inhibitors
can affect how well an enzyme functions.
These factors can change the shape of an
enzyme and cause it to lose its biological
properties. This results in the enzyme
becoming less effective and unable to
function.
III. Summary of TEKS
2G: Analyze, evaluate, make inferences, and predict trends from data.
9A: Compare the structures and functions of different types of biomolecules, including carbohydrates, lipids,
proteins, and nucleic acids.
9C: Identify and investigate the role of enzymes.
9D: Analyze and evaluate the evidence regarding formation of simple organic molecules and their organization
into long complex molecules having information such as the DNA molecule for self-replicating life.
IV. Questions
1. Which of these diagrams best represents a section of the structure of an enzyme?
B.
C.
A.
2. What is the name of the monomer that correctly identifies this structure?
This is a monosaccharide (single sugar).
3. What is the name of the monomer for this structure, and what is its function?
This is a nucleotide, and stores and transmits genetic information.
4. Describe how DNA and RNA are different.
DNA nucleotides have a phosphate group, nitrogen bases, and deoxyribose sugar;
RNA nucleotides have a phosphate group, nitrogen bases, and ribose sugar.
5. Beeswax is which of the following types of organic molecule? Lipids
6. The function of biomolecules is directly related to the order of its monomers. Which biomolecule will be most affected by the order of its
monomers? Proteins
7.
The graph shows the rate of enzymatic reaction and how pH affects it. The optimum (best) pH for this enzyme is indicated on the graph.
a. What is the optimum pH? 6
b. What happens to enzyme after it reaches the optimum pH? The shape may change (denaturing), and this affects the enzyme’s
ability to function; therefore, the rate of the reaction decreases once the optimum pH is exceeded.
c. Identify the independent and dependent variables for the graph. IV- pH levels are changed (x-axis); DV rate or speed of the
reaction is measured (y-axis)