Flashcards
Biochem Module 4
Cards in this deck (33)
- 1Which structure determines the properties of a protein?Primary structure
- 2What is a primary structure of a protein?the amino acid sequence of its poly peptide chain
- 3What is the secondary structure referring to?spatial arrangement of the backbone without regard to the side chain conformations
- 4Describe how alpha helices are formedthe backbone carbonyl of residue i accepts an H-bond from the backbone N-H group of residue i+4
- 5What are the 2 types of beta-sheets?Parallel and antiparallel beta-sheets
- 6How are beta-sheets stabilized?By H-bonds between two parallel backbones
- 7what is the difference between parallel and antiparallel beta-sheets?Parallel: backbones extend in the same directions
Antiparallel: the backbones extend in opposite directions - 8Proteins are either classified as ____ or _____ depending on their overall shapefibrous or globular
- 9What is the most abundant vertebrate protein?Collagen
- 10Is Collagen fibrous or globular?Fibrous
- 11what residues are abundant in collagen?glycine, proline and hydroxyproline
- 12what is the role of collagen triple-helix fibers?major stress-bearing components of connective tissues and the fibrous matrices of skin and blood vessels
- 13how are the proline residues in collagen hydroxylated?with help of enzyme, prolyl hydroxylase and coenzyme ascorbic acid (vit. c)
- 14Lack of vitamin c results in ____scurvy
collagen can't form fibers - 15what does the tertiary structure of a protein refer to?the folding of its secondary structure segments
- 16when secondary structure segments fold, the segments are joined by _____reverse turns, which usually occur on the surface of protein
- 173D structure of proteins are studied experimentally byx-ray crystallography, NMR, spectroscopy and molecular modeling
- 183-D structures of proteins are deposited in the ____Brookhaven Protein Data Bank
- 19atoms in proteins are _______tightly packed
- 20when visualizing proteins, we usually only visualizebackbones
- 21how are alpha-helices drawn?as ribbons passing via the C-alpha atoms
- 22how are beta-sheets drawn?as flat arrows pointing toward the C-terminus
- 23True or false: unfolding of a protein requires a large amount of free energyFalse: unfolding of a protein may require free energy as small as 0.4 kJ/mol per residue
- 24where do hydrophobic and hydrophilic residues prevail?hydrophobic: in the protein interior
hydrophilic: protein surface - 25what is the role of myoglobin?intracellular protein facilitating O2 transport in vertebrate muscle
- 26what does the heme group in myoglobin do?coordinates the central Fe (II) atom
Oxygen binds reversibly to the heme group in protein - 27what comprises a heme group?4 nitrogen atoms coordinate the central Fe (II) atom
- 28why are CO and NO considered toxic?they bind with much higher affinity to heme group than O2
- 29what happens if Fe(II) is converted to Fe(III)?myoglobin is converted to metmyoglobin (responsible for brown color of old meat ad dried blood)
- 30what is hemoglobin?major component of erythrocytes, transports O2 from the lungs to respiring tissue that returns CO2
- 31what is hemoglobin comprised of?tetramer consisting of two alpha and two beta subunits (each subunit similar to each other and myoglobin)
- 32what is sickle-cell anemia?hereditary disease caused by recessive gene of hemoglobin variant in which beta-chain has Val^6 instead of Glu^6 in normal hemoglobin
- 33Why is Val^6 bad?it fits into a hydrophobic pocket on another hemoglobin molecule causing hemoglobin molecules to polymerize and form fibers that cause erythrocyte deformation
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- Flashcards on Biochem Module 4, created by A D on 16/04/2016.
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