Download Protein Unit Study Guide/Review Sheets

Accelerated Nutrition
Protein Unit Study Guide/Review Sheets
Answer Key I
GENERAL PROTEIN STRUCTURE and AMINO ACID CLASSIFICATION:
1.
2.
3.
4.
5.
6.
What element(s) ALWAYS comprise proteins? C, H, O, N
Are proteins organic? YES
What element(s) MAY be present in proteins? S
What is the name of the monomer of proteins? AMINO ACID
What type of bond links amino acids together? PEPTIDE BOND
What functional groups is shared between ALL amino acids (giving it its name..)? AMINO
GROUP & ACID GROUP
7. What functional group on an amino acid differentiates it from, for example, a carbohydrate?
R GROUP; VARIANT GROUP
8. Is the group from question #7 the same or different on each amino acid? DIFFERENT
9. How many standard amino acids are there? 20
10. How many (of the standard amino acids) can our bodies synthesize? 11
11. What are the amino acids that our body can synthesize named? NON-ESSENTIAL AMINO
ACIDS
12. How many (of the standard amino acids) can’t our bodies synthesize? 9
13. What are the amino acids that our body can’t synthesize named? ESSENTIAL AMINO ACIDS
14. If our bodies can’t synthesize certain amino acids, where do we get them from? DIET
15. Why is it important that we have all of the twenty amino acids? IF YOU DON’T HAVE 1 YOU
NEED TO MAKE A PROTEIN (THINK PRIMARY STRUCTURE) YOU CAN’T SYNTHESIZE THAT
PROTEIN
16. What neutral molecule is formed when amino acids bonds together? WATER
17. What are the names of a molecule that has 100 amino acids linked together (two
answers)? PROTEIN A.K.A POLYPEPTIDE “MANY PEPTIDE BONDS”
18. Explain how three different proteins can be composed of 50 amino acids.
a. SAME AMINO ACIDS, DIFFERENT ORDERS (2) OR DIFFERENT AMINO ACIDS (1) BUT
ALL CONTAIN 50
QUALITATIVE TESTING FOR AMINO ACIDS AND PROTEINS
19. List the names of the qualitative tests used to identify amino acids and proteins and list and
draw the functional group(s) that it tests for.
Ninhydrin
Biuret
Lead Acetate
Sakaguchi’s
Xanthroproteic
Ammonia (NH3) or
Primary Amine (NH2)
or
Secondary Amine (NH)
PEPTIDE BONDS or
2 or more amides
(N-C=O)
Sulfur groups
Guanidines
Phenyl
groups/substituted
aromatic RINGS
Any protein has
to have peptide
bonds ;)
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Protein Unit Exam Answer Key II
LEVELS OF PROTEIN STRUCTURE
20. Define the primary structure: THE SEQUENCE OF AMINO ACIDS
21. Describe the type of bonding in secondary structure and where it occurs: HYDROGEN
BONDING WITHIN THE POLYPEPTIDE BACKBONE
22. Two types of secondary structure: ALPHA HELIX (“TWISTED”) AND BETA SHEET
(FLAT AND FOLDED “ACCORDIAN”)
23. Four chemical interaction that occur in tertiary structure: SALT BRIDGES (ACID-BASE,
IONIC BONDS); DISULFIDE BONDS (S-S); HYDROGEN BONDING (EXAMPLE:
N-H-O; MUST HAVE TWO ELECTRONEGATIVE ATOMS); AND NON POLAR
HYDROPHOBIC (WATER FEARING, TWISTS AWAY FROM WATER)
24. Two types quaternary structure: FIBROUS (LONG, STRINGY); AND GLOBULAR
(LIKE A BLOB)
25. Compare tertiary and quaternary structure: TERTIARY STRUCTURE INVOVLES
ONLY ONE POLYPEPTIDE CHAIN; QUATERNARY STRUCTURE IS WHEN TWO
POLYPEPTIDE CHAINS INTERACT
CLASSIFICATION and FOOD SOURCES
26. What makes a protein complete? A PROTEIN IS COMPLETE IF IT CONTAINS ALL
OF THE ESSENTIAL AMINO ACIDS
27. What are food sources of complete proteins? ANIMAL PRODUCTS; MEAT, MILK
28. What makes a protein incomplete? A PROTEIN IS INCOMPLETE IF IT DOES NOT
CONTAIN ALL OF THE ESSENTIAL AMINO ACIDS
29. List food sources of incomplete proteins. VEGETABLES
PROTEIN FUNCTION
30. What is the relationship between structure and function? STRUCTURE DETERMINES
FUNCTION
31. Can proteins provide energy? YES, 4 KCALS/GRAM
32. Explain why proteins are generally not used as a source of energy. PROTEINS HAVE SO
MANY VARIOUS VITAL ROLES THAT IT IS NOT FAVORABLE TO USE THEM
FOR ENERGY
33. How do proteins protect you from illness? SOME PROTEINS FUNCTION AS
ANTIBODIES, WHICH “MARK” FOREIGN INVADERS (BACTERIA, VIRUSES)
FOR DESTRUCTION
34. How are proteins involved in letting your body know what to do and when to do it? SOME
PROTEINS ARE HORMONES; HORMONES SIGNAL ANOTHER PART OF YOUR
BODY TO DO SOMETHING, MAKE SOMETHING, ETC.
35. How are proteins involved in, for example, getting oxygen to your cells? SOME
PROTEINS FUCTION AS TRANSPORTERS AROUND YOUR BODY (LIKE
HEMOGLOBIN DELIVERING OXYGEN TO YOUR CELLS); SOME PROTEINS
FUNCTION AS TRANSPORTERS FROM THE OUTSIDE OF A CELL OR
MEMBRANE TO THE INSIDE OF A CELL OR MEMBRANE (LIKE ATP
SYNTHASE LETTING H+ IONS THROUGH THE MEMBRANE DURING
CHEMIOSMOSIS)
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36. How are proteins involved in the acid-base balance of your body? SOME PROTEINS ACT
AS BUFFERS; HELP BODY RESIST CHANGE IN PHIF TOO ACIDIC, “TAKE
UP” H+; IF TOO BASIC, RELEASE H+
37. How are proteins involved in the fluid balance of your body? VERY SIMPLY, BECAUSE
OF THE PRESENCE OF CERTAIN PROTEINS IN THE BLOOD, FLUID MOVES
BACK FROM TISSUES INTO THE BLOODSTREAM; WITHOUT THESE
PROTEINS, FLUID BUILDS UP INSIDE TISSUES, AND THE TISSUE SWELLS
38. What structural role do proteins fulfill? PROTEINS FORM HAIR, NAILS, MUSCLES,
TENDONS AND LIGAMENTS
39. FIBROUS: LONG, THIN, ABLE TO CONTRACT MUSCLE; GLOBULAR: MOVE
THROUGH BLOODSTREAM, CARRY THINGSHEMOGLOBIN (GLOBULAR)
FUNCTION: ENZYMES
40. Define enzyme. SPECIALIZED PROTEINS THAT CATALYZE BIOCHEMICAL
REACTIONS
41. Why is an enzyme’s shape so important? Explain the “lock and key” model. EACH
ENZYME ONLY CATALYZES ONE SPECIFIC REACTION; FOR EXAMPLE
CATALASE ONLY CATALYZES THE REACTION H202  H2O + O2; THE
STRUCTURE OF THE ENZYME, CATALASE, MUST FIT THE STRUCTURE OF
THE SUBSTRATE, H2O2, PERFECTLY OR THE REACTION CANNOT BE
CATALYZED AND WILL NOT HAPPEN; THIS “FITTING” IS REFERRED TO AS
THE LOCK AND KEY (ENZYME-SUBSTRATE COMPLEX); THIS EMPHASIZES
THE IMPORTANT OF STRUCTURE = FUNCTION
42. Explain what happens to this enzyme’s activity at 55 degrees AND WHY:
THE ENZYME STOPS WORKING BECAUSE IT IS TOO FAR AWAY FROM ITS
OPTIMUM TEMPERATURE OF 40; IT MAY BE DENATURED, WHICH MEANS ITS
SHAPE HAS BEEN CHANGED; SINCE ENZYME FUNCTION ON STRUCTURE, IF ITS
SHAPE IS CHANGED, IT CAN’T FUNCTION
43. What will happen to the rate of an enzyme reaction as it is heated from very cold (near
freezing) to very hot (boiling)?
b. it will increase, then decrease, then be zero
44. At which pH do enzymes function best?
e. The optimal pH depends on the particular enzyme
CATALASE LAB
45. What effect do extreme environments have on the functionality of enzymes? What is this the
direct result of? Extreme environments disrupts bonding and the enzyme loses
structure.
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