Amino Acids Flashcards
With OH as R group
Serine
ThreonineTyrosine
Amino acids with aliphatic side chains
Glycine Alanine Valine Leucine Isoleucine
With sulfur atoms
Cysteine
Methionine
With imino acid side chain
Proline
Molecules that contain an equal number of ioniz-able groups of opposite charge and that therefore bearno net charge are termed ______
Zwitterions
Both D-amino acids and non-α-amino acids occurin nature, but only _- α-amino acids are present inproteins.
L configuration
primary structure of a peptideis its amino acid sequence, starting from the _____-terminal residue.
Amino
are compact, are roughly sphericalor ovoid in shape, and have axial ratios (the ratio oftheir shortest to longest dimensions) of not over 3..
Globular proteins
Primary structure, the sequence of the aminoacids in a polypeptide chain;
secondary structure, thefolding of short (3- to 30-residue), contiguous segmentsof polypeptide into geometrically ordered units;
ter-tiary structure, the three-dimensional assembly of sec-ondary structural units to form larger functional unitssuch as the mature polypeptide and its component do-mains;
quaternary structure, the number andtypes of polypeptide units of oligomeric proteins andtheir spatial arrangement.
Which among is considered false?
None of the above
proteins participate in the folding of overhalf of mammalian proteins.
Chaperones. Heast shock proteins (hsp)
Refolding or misfolding of another protein endogenousto human brain tissue, β-amyloid, is also a prominentfeature of ____
Alzheimer’s disease
most abundant of the fibrous proteinsthat constitute more than 25% of the protein mass inthe human body.
Collagen
Prions—protein particles that lack nucleic acid—cause fatal transmissible spongiform encephalopa-thies such as
Creutzfeldt-Jakob disease, scrapie, kuru, and bovine spongiform encephalopathy.
cyclictetrapyrrole consisting of four molecules of pyrrolelinked by α-methylene bridges
Heme
subunit compositionof the principal hemoglobins are
α β (HbA; normaladult hemoglobin),
α2γ2 (HbF; fetal hemoglobin),
α2 2 2S2(HbS; sickle cell hemoglobin),
α δ
2 2 (HbA2; aminor adult hemoglobin).
Which of the enumerated has resistance to malarial infection?
Sickle hemoglobin
Which has coopertavie binding with oxygen?
Hemoglobin
Myoglobin
Hemoglobin
Deoxyhemoglobin binds one proton for every twoO2 molecules released, contributing significantly to thebuffering capacity of blood. The somewhat lower pH ofperipheral tissues, aided by carbamation, stabilizes theT state and thus enhances the delivery of O2. In thelungs, the process reverses. As O2 binds to deoxyhemo-globin, protons are released and combine with bicar-bonate to form carbonic acid. Dehydration of H2CO3,catalyzed by carbonic anhydrase, forms CO2, which isexhaled. Binding of oxygen thus drives the exhalationof CO2 (Figure 6–9).This reciprocal coupling of protonand O2 binding is termed _____
bohr effect
transition of hemoglobin from theT (taut)state to the R (relaxed) state. Which is low oxygen affinity?
Taut or T form
Mutations (eg, hemoglobin Chesapeake) that favorthe R state increase O2 affinity. These hemoglobinstherefore fail to deliver adequate O2 to peripheral tis-sues. The resulting tissue hypoxia leads to _____, an increased concentration of erythrocytes.
Polycythemia
Mutations in the genes that encode the α or β subunitsof hemoglobin potentially can affect its biologic func-tion. However, almost all of the over 800 known mu-tant human hemoglobins are both extremely rare andbenign, presenting no clinical abnormalities. When amutation does compromise biologic function, the con-dition is termed a _____
Hemoglobinopathy
Two questions: In HbS, the nonpolar amino acid ____ has replacedthe polar surface residue Glu6 of the β subunit, gener-ating a hydrophobic “sticky patch” on the surface ofthe β subunit of both oxyHbS and deoxyHbS. If HbC glu6 is substited by amino acid ____
HbS: valine
HbC: lysine
Following massive crush injury, myoglobin releasedfrom damaged muscle fibers colors the urine dark red urine termes as:
Myoglobinuria
When blood glucose enters the erythrocytes it glycosy-lates the ε-amino group of lysine residues and theamino terminals of hemoglobin. The fraction of hemo-globin _______, normally about 5%, is proportion-ate to blood glucose concentration. Since the half-life ofan erythrocyte is typically 60 days, the level of _____reflects the mean blood glu-cose concentration over the preceding 6–8 weeks.Measurement of _____ therefore provides valuable in-formation for management of diabetes mellitus.
HbA1c
