CHEMISTRY & SOCIETY QUEST 12
PROTEINS AND LIMITING REACTANTS
Name ______
Date______Period_____
MATCHING
1.____Peptide bond a) Type of protein that acts as “matchmaker” for substrates
2.____Essential amino acid b) Molecule that speeds up the rate of a reaction without being changed itself 3.____Complete protein c) Amino acid the body must obtain from foods
4.____Complementary protein d) Reactant that gets used up first, and determines amount of product made
5.____Catalyst e) Linkage of C- to –N found in the formation of proteins
6.____Condensation reaction f) Type of reaction that always has H20 given off
7.____Enzyme g) Reactant that does NOT run out first
8.____Limiting Reactant h) Food that provides all essential amino acids
9.____Excess Reactant i) Series of reactions the body uses to break down foods to provide energy
10.___Metabolism j) Combination of two foods that provide all essential amino acids
SHORT ANSWER
11. What element is present in all amino acids, but is not present in fats and proteins? ______
12. How many amino acids are there? ______
13. How many essential amino acids are there? ______
14. Provide two specific examples of proteins and tell what they do in the body.
______
______
15. Provide an example of complementary proteins: ______
16. Provide an example of a complete protein? ______
17. Circle the amine functional group and put a square around the carboxylic acid group in the following amino acid.
18. What determines the amount of product that can be made in a chemical reaction? ______
19. Explain what was responsible for the difference in the rate of fizzing of hydrogen peroxide between boiled
and unboiled food samples in the enzymes lab activity.
______
______
MULTIPLE CHOICE
20. An empty, clean, dry beaker weighs 34.58 g. The beaker and a milk sample weigh 51.87 g. After extracting, filtering, and drying the protein portion of the milk, the protein and the filter paper weighs 1.01 g. The dry, clean filter paper weights 0.39 g. Use the above data to determine the percent of protein in the milk sample. Which response below is closest to the correst answer?
a) 0.62% b) 1.9% c) 3.6% d) 17.29%
21. What is precipitated when orange juice is added to milk and chunks (sorry Erin) are formed in the milk?
a) protein b) fat
c) water d) carbohydrates
22. Choose the enzyme from the following molecules:
a) lactic acid b) lactose
c) lycine d) lactase
PROBLEMS
The following equation illustrates the reaction between Magnesium metal and HCl. You are given 12 moles of Mg and 20 moles of HCl.
Mg + 2HCl MgCl2 + H2
23. Determine the limiting reactant
24. Determine the excess reactant
25. Determine the number of moles of excess reactant used
26. Determine the number of moles of excess reactant left over
27. Determine the number of moles of H2 that can be made
28. Determine the number of grams of H2 that can be made