BIOL101: MasteringBiology CH. 3 – Flashcards
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Most protein enzymes catalyze only one specific chemical reaction effectively. What feature of protein structure is most directly responsible for this specificity?
A-The specific geometry and types of amino acids outside the active site
B-Most protein enzymes have rigid, static structures essential to their specificity.
C-The specific geometry and types of amino acids in the active site
D-The specific geometry and types of nucleotides in the active site
answer
C-The specific geometry and types of amino acids in the active site
The active site is the location in an enzyme where substrates (reactants) bind and where catalysis occurs.
In the figures provided, both state *INSIDE* the active site versus outside.
question
The secondary structure of proteins results because of ___ bonding between atoms in the protein's backbone.
A-hydrophobic
B-hydrogen
C-covalent
D-ionic
answer
B-hydrogen
H bonds are responsible for producing the *alpha-helix and beta-sheet* secondary structures.
question
Nonpolar amino acid residues are typically found in the interior of globular proteins like trypsin. Which chemical force is most directly responsible?
A-Covalent bonding
B-Tertiary structure
C-Ionic bonding
D-Hydrophobic interactions
answer
D-Hydrophobic interactions
In aqueous solution, water molecules interact with the hydrophillic polar side chains and force the hydrophobic nonpolar side chains to coalesce in the interior of the folded protein.
question
Proteins help cells with which task(s)?
A-transport
B-catalysis
C-signaling
D-all of the above
answer
D-all of the above
Definition of proteins.
Proteins serve many different functions in cells, partly because they can take on so many different structures.
question
If cells are grown in a medium containing radioactive 35S, which of these molecules will be labeled?
A-nucleic acids
B-proteins and nucleic acids
C-proteins
D-amylose
E-phospholipids
answer
C-proteins
*Phosphorus 32P as to DNA. Sulfur 35S as to Protein. *
>>*Hershey and Chase* knew that T2 consisted of only DNA and protein, and that they somehow manipulated host cells to produce new phages, but did not know if DNA or protein was responsible.
Hershey and Chase radioactively labeled E.Coli and T2 with 32P (phosphorus isotope) and 35S (sulfur isotope) because they knew DNA contains phosphorus, and *protein contains sulfur,* but not vice versa.
They infected the 32P E.Coli with 32P T2 and 35S E.Coli with 35S T2, and collected the progeny. The results found that the progeny collected from the 32P E.Coli and 32P T2 contained the 32P isotope, while the 35S strains did not, providing more evidence that DNA was the genetic information that bacteriophages inject into bacteria, not protein. -explained via yahoo!
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Which of the following is true of protein folding?
A-Once proteins fold, their structure doesn't change.
B-Correct folding is aided by high temperatures.
C-Misfolded proteins can still function correctly.
D-Some proteins can fold spontaneously.
answer
D-Some proteins can fold spontaneously.
This was shown in experiments with ribonuclease by Anfinsen in 1950s: The Anfinsen experiment: spontaneous folding>>
"This experiment demonstrated that all the information necessary to determine the three-dimensional fold was incorporated in the amino acid sequence. A large number of proteins have now
been shown to be able to be *renatured* in similar experiments. Thus, it is clear that virtually all proteins, under appropriate conditions, can be reversibly unfolded and *refolded* into their native structure under in vitro conditions." - http://www4.ncsu.edu/~franzen/public_html/CH795I/lectures/folding/tsld011.htm
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Which statement accurately explains how you could use the structural formula of an amino acid's R-group (side chain) to determine if it is acidic, basic, or nonpolar?
A-Acidic R-groups contain a carboxyl functional group.
B-Acidic R-groups contain an amino functional group.
C-Basic R-groups contain a carboxyl functional group.
D-Nonpolar R-groups contain an amino functional group.
answer
A-Acidic R-groups contain a carboxyl functional group.
Although all amino acids contain at least one carboxyl group, the only side chains that do belong to acidic: Asp and Glu.
Acidic: Asp, Glu
Basic: Arg, Lys, His
Hydrophobic: Gly, Ala, Val, Leu, Ile, Pro, Phe, Met, and Trp
Polar and NO Charge: Ser, Thr, Cys, Asn, Gln, and Tyr
-https://www.chem.wisc.edu/deptfiles/genchem/netorial/modules/biomolecules/modules/protein1/prot11.htm
question
Which biological activity does NOT directly involve proteins?
A-Breaking food polymers into smaller molecules.
B-Defending cells against viruses.
C-Sensing light.
D-Changing the shape of a cell.
E-None of the above; proteins are involved in all of them.
answer
E-NONE
Proteins are multi functional and involve in many more.
Proteins are also used to attack prey organisms, as in spider and snake venoms; to lubricate and clean the body, as in mucus proteins; to help other proteins to fold properly; to help coil and uncoil DNA; and so on. The hemoglobin molecule is a four-part protein that transports oxygen (O2) from the lungs to tissues of the body.
-Many proteins change their shapes as they work. We can see, hear, feel, and taste because signals alter the shapes of sensory proteins. We can move because signals alter the shapes of motor proteins. Heat, dehydration, and some poisons kill by altering protein shape.
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Protein structure is conceptually divided into four levels, from most basic to higher order: Primary structure describes the order of amino acids in the peptide chain. Secondary structure describes the basic three-dimensional structures, α-helices and β-sheets. Tertiary structure describes how the secondary structures come together to form an individual globular protein. Quaternary structure results from individual proteins coming together to form multi-subunit protein complexes.
answer
Part A
1. Quaternary structure is the result of two or more protein subunits assembling to form a larger, biologically active protein complex.
2. Tertiary structure is achieved when a protein folds into a compact, three-dimensional shape stabilized by interactions between side-chain R groups of amino acids.
3. Primary structure is the sequence of amino acids in a protein.
4. Secondary structure describes the alpha-helices and beta-sheets that are formed by hydrogen bonding between backbone atoms located near each other in the polypeptide chain.
Part B
See image attached.
question
Which polymers are composed of amino acids?
Carbohydrates
Monomers
Proteins
Nucleic acids
answer
Proteins.
Amino acids are building blocks of proteins.
question
Which of the following is not attached to the central carbon atom in an amino acid?
An oxygen
A side chain ("R group")
An amino functional group
A carboxyl functional group
answer
oxygen.
The central carbon atom in an amino acid is bonded to an amino acid functional group, a carboxyl group, a side chain, and *hydrogen.*
See image attached.
question
Which part of an amino acid is always acidic?
Amino functional group
Side chain ("R group")
Carboxyl functional group
None of the above
answer
Carboxyl functional group.
The carboxyl group (COOH) contains two oxygen atoms that tend to pull electrons away from H atom, so this group tends to lose a proton and is acidic.
question
Which monomers make up RNA?
Simple sugars
Nucleotides
Amino acids
Polymers
answer
Nucleotides.
Nucleotide monomers make up nucleic acid. RNA stands for riboNUCLEIC ACID.
question
Which of the following statements about the formation of polypeptides from amino acids is true?
A-A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.
B-The reaction occurs through the addition of a water molecule to the amino acids.
C-Polypeptides form by condensation or hydrolysis reactions.
D-A bond can form between any carbon and nitrogen atom in the two amino acids being joined.
answer
A-A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.
A Hydroxyl group is removed from carboxyl group of one amino acid and H is removed from amino group of the other amino acid, allowing a bond to form between the two groups.
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True or False: Enzymes in the digestive tract catalyze hydrolysis reactions.
answer
True.
Enzymes in the digestive tract break down food molecules, which is a process that occurs by hydrolysis.
question
Proteins are polymers of _____.
hydrocarbons
nucleotides
CH2O units
amino acids
glycerol
answer
amino acids
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What type of bond joins the monomers in a protein's primary structure?
hydrogen
peptide
hydrophobic
ionic
S - S
answer
peptide
Monomers in primary structure = amino acids. Amino acids of protein are linked by peptide bonds.
question
The secondary structure of a protein results from _____.
hydrogen bonds
peptide bonds
bonds between sulfur atoms
ionic bonds
hydrophobic interactions
answer
H bonds.
Electronegative oxygen and nitrogen atoms leave H atoms with partial positive charges.
question
Tertiary structure is NOT directly dependent on _____.
hydrophobic interactions
peptide bonds
bonds between sulfur atoms
hydrogen bonds
ionic bonds
answer
Peptide bonds.
They link together amino acids of a protein's primary structure.
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Amino acids are the building blocks of proteins. There are 20 amino acids that most commonly occur in proteins. Based on the functional group making up their side chain, or R group, amino acids are classified as acidic, basic, or neutral. The physical and chemical properties of the R group determine the unique characteristics of each amino acid.
Hints:
-*Acidic amino acids have acidic R groups. Their electrically charged R groups make these molecules highly soluble in water.*
-*Basic amino acids have basic R groups. Their electrically charged R groups make these molecules highly soluble in water.*
-*Neutral (neither acidic nor basic) amino acids can be further classified as nonpolar or polar. The neutral nonpolar amino acids have R groups that contain no charged atoms; most of these amino acids are not water soluble. The neutral polar amino acids have R groups that have a dipole moment. The partial charges in their R groups make these molecules generally water soluble.*
It important for you to understand how amino acids are classified, rather than just looking up the answers to this tutorial in your book. The hints provided here will teach you how to figure out the classifications without looking them up. That way you won't have to memorize them when you are tested on this material.
answer
-
Acidic: Asp, Glu
Basic: Arg, Lys, His
Hydrophobic: Gly, Ala, Val, Leu, Ile, Pro, Phe, Met, and Trp
Polar and NO Charge: Ser, Thr, Cys, Asn, Gln, and Tyr
-https://www.chem.wisc.edu/deptfiles/genchem/netorial/modules/biomolecules/modules/protein1/prot11.htm
question
What name is given to the process seen in this animation?
To view the animation, click here. Then click on the image to start the animation.
monomerization
catabolism
hydrolysis
water formation
dehydration synthesis
answer
Dehydration synthesis.
Linking of monomers involves removal of water.
view animation at:
http://media.pearsoncmg.com/bc/bc_campbell_biology_8/img/activities_quizzes/0501q.swf
