BIO206H5 Study Guide - Tryptophan, Isoleucine, Alpha Helix

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mauvelizard469

5 Oct 2014

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Atoms & ions | chemical bonding | water | acid & bases | organic compounds | carbohydrates | lipids | Proteins | enzymes | nucleic acids | atp. Proteins are made by building long chains of amino acids. The r side chain is attached to central carbon. Each r side chain has a different structure to it. Twenty different types of side chains (20 amino acids) Amino acids are linked together to form long chains. Linked together by peptide bonds a special covalent bond found in proteins. After the chains of amino acides are constructed, they can fold into more complex structures. Primary - exact sequence of amino acids before folding. Tertiary - folding results in complex 3d structures. Quaternary - multiple 3d subunits organized into a bigger structure. Carries oxygen in the blood- it"s made up of 4 specific 3d subunits. Proper protein function depends on correct 3d structure.

Related Questions

Identify amino acids which when being part of a protein structure have side chains that can participate in the hydrogen bond formation. Draw the structure of each amino acid and indicate how it can form the hydrogen bonding.

2. Identify amino acids which when being part of a protein structure have side chains that can participate in chemical reactions. Explain why and how. For instance which residues are used for post-translational modifications, for regulation of protein activity, how are glycans and lipids attached to proteins?

3. Identify amino acids which when being part of a protein structure have side chains that can ionize or are charged at pH 7. Based on the pK_R values of the free amino acids estimate/calculate what percentage of the amino acid is in the charged form.

Explain why some amino acids, like serine in serine proteases, can ionize/lose proton at neutral pH while their pK_R values suggest that this should not be possible.

sapphireant197

1. The side chain of tyrosine is considered to be polar because even though it is reminiscent of phenylalanine it also has two types of atoms that have large differences in electronegativity with asymmetry at the terminus.

a.) True

b.) False

2. Which of these changes in primary structure will be certain to cause a loss of protein activity?

a.) Asp to Glu

b.) His to Lys

c.) Trp to Ser

d.) Gly to Pro

e.) Not enough information is given since any one of these changes could be severe depending on the context of the situation

3.The difference between fetal and adult hemoglobin with regard to oxygen binding occurs because fetal hemoglobin has an amino acid substitution in one of its chains that results in a histidine (adult version) being replaced by a serine (fetal version).

a.) True

b.) False

4. What will likely happen if the side chains of aspartate and histidine at pH 5 are next to each other in a polypeptide chain?

a.) The side chains of these amino acids will be uncharged and there will be no electrostatic effect.

b.) The side chains of these amino acids will be charged and they will attract each other.

c.) The side chains of these amino acids will be charged and they will repel each other.

d.) Not enough information is given to determine the effect.

5. A beta pleated sheet:

a.) can occur between two different polypeptide chains
b.) can be formed by either intramolecular or intermolecular hydrogen bonds
c.) can only form when cysteines form disulfide bridges within this structure
d.) forms when side chains of D and E attract each other
e.) both a and b

lilacmammoth542

1 The side chain of valine is not polar because it does not havetwo types of atoms that have large differences inelectronegativity

a.) True b.) False

2 Ethanol is a polar molecule because there are largedifferences in electronegativity of the atoms and the molecule isasymmetric in shape.

a.) True b.) False

3 Which best describes a protein that is found in thecytosol?

a.) Polar amino acids will be found on the surface b.) Acidicamino acids will be found on the surface

c.) Basic amino acids will be found on the surface d.) Non-polaramino acids will be found in the interior

e.) All of the above

4 What will likely happen if two glutamates at pH 5 are next toeach other in a polypeptide chain?

a.) The side chains of these amino acids will be uncharged andthere will be no effect.

b.) The side chains of these amino acids will be charged andthey will attract each other.

c.) The side chains of these amino acids will be charged andthey will repel each other.

d.) Not enough information is given to determine the effect.

5 The difference between fetal and adult hemoglobin with regardto oxygen binding occurs because fetal hemoglobin has an amino acidsubstitution in one of its chains that results in a serine beingreplaced by a histidine.

a.) True b.) False

cyanseal60

BIO206H5 Study Guide - Tryptophan, Isoleucine, Alpha Helix

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