Biology I
Unit 2: Biochemistry
Biomolecules & Energy 2.3-2.4
Name: ________________________
Date: _______________ Hour: ____
Reviewing Key Concepts
Identifying On the lines provided, identify each statement as describing: carbohydrates, lipids,
nucleic acids, or proteins.
_______________1. the main source of energy for living things
_______________2. help carry out chemical reactions
_______________3. important parts of biological membranes
_______________4. contain hydrogen, oxygen, nitrogen, phosphorus and carbon
_______________5. transport substances in and out of cells
_______________6. composed of amino acids
_______________7. sugar and starches
_______________8. store and transmit hereditary information
Completion On the lines provided, complete the following sentences.
9. When two or more _____________________ join together, a polymer forms.
10. Many of the molecules in living cells are so large they are called ______________________.
11. Lipids are made up of fatty acids and ____________________________.
12. Glucose, galactose and fructose are carbohydrates called __________________________.
13. The two basic kinds of nucleic acids are _________________ and __________________.
14. __________________________ are polymers of amino acids.
15. A fatty acid with the maximum number of hydrogen atoms possible is ______________________.
16. During a chemical reaction, chemical bonds are ________________________.
17. Biological catalysts, or enzymes, act by lowering the ______________________________
required for a reaction
18. The reactants of an enzyme-catalyzed reaction are known as ________________________.
-1-
Short Answer
19. What is the difference between reactants and products?
___________________________________________________________________________
___________________________________________________________________________
20. How is a substrate and its enzymes like a lock and key?
___________________________________________________________________________
___________________________________________________________________________
21. Most enzymes in the human body work best at 37˚C (normal body temperature). Imagine that
scientists have discovered an enzyme in the body that works best at 39˚C.
a. What is the word used to describe a body temperature above normal? ________________
________________________________________________________________________
b. With what processes or functions might this enzyme be involved? __________________
________________________________________________________________________
22. The graphs below show the amount of energy present during two chemical reactions.
● Label each reaction as endothermic or exothermic.
● Label the reactants and products.
● Draw an arrow on each to show the activation energy.
Type of reaction:
Type of reaction:
a. Which graph shows the greatest activation energy? _________________________________
b. What is released or absorbed whenever chemical bonds form or are broken? _____________
c. Which reaction helps maintain human body temperature? ____________________________
-2-