A newly identified viral protein contains one long α-helix spanning 60 amino acid residues. The number of main chain H-bonds formed in this helix is __________.
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Which one or more of the following statements correctly describe(s) the addition of N-nucleotides during the rearrangement of the immunoglobulin heavy chain-encoding gene? (A) Addition of N-nucleotides is template encoded. (B) N-nucleotides are added by terminal deoxynucleotidyl transferase. (C) The added N-nucleotides are common in V-D and D-J junction. (D) N-nucleotides are added by the … Read more
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In mammals, hematopoietic stem cells that give rise to different types of blood cells are known as (A) totipotent stem cells. (B) pluripotent stem cells. (C) myeloid progenitor cells. (D) lymphoid progenitor cells.
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Which one of the following metabolic intermediates is common to glycolysis, nucleotide synthesis, and glycogen synthesis? (A) Citrate (B) Oxaloacetate (C) Glucose 6-phosphate (D) Glycerol 3-phosphate
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Mammalian cells cultured at low temperature (25 to 30°C) lead to an increased sterol content in the membrane. Elevated sterols in the membrane result in (A) an enhancement in membrane fluidity. (B) stabilization of membrane proteins. (C) an increase in membrane permeability to water. (D) a decrease in membrane fluidity.
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Which one of the following pairs of amino acids is NOT incorporated in a polypeptide chain? (A) 4-Hydroxyproline and γ-carboxyglutamate (B) γ-Carboxyglutamate and desmosine (C) Ornithine and citrulline (D) 4-Hydroxyproline and 5-hydroxylysine
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