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TLS Online TPP Program

#Question id: 10159

The ambient temperature exerts an important influence over Ω and the concentrations of CO2 and O2 around the active site of rubisco. Warmer environments have the effect of;  Find the incorrect one?

#Unit 6. System Physiology – Plant
  1. increasing the oxygenase activity of rubisco more than the carboxylase activity. The greater increase of KC for CO2 than of KO for O2 diminishes the W of rubisco
  2. The increase of [O2]/[CO2] decreases the vC/vO ratio; that is, the oxygenase activity of rubisco prevails over the carboxylase activity
  3. Increasing the stomatal aperture to conserve water, the stomatal closure the uptake of atmospheric CO2, thereby decreasing CO2 at the active site of rubisco

  4. warmer environments significantly limit the efficiency of photosynthetic carbon assimilation because the progressive increase in temperature tilts the balance away from photosynthesis (carboxylation) and toward photorespiration (oxygenation)

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TLS Online TPP Program

#Question id: 33358

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following situations would produce a Hill plot with n<  1.0?
(a) The protein has multiple subunits, each with a single ligand-binding site. Binding of ligand to one site decreases the binding affinity of other sites for the ligand.
(b) The protein is a single polypeptide with two ligand-binding sites, each having a different affinity for the ligand.
(c) The protein is a single polypeptide with a single ligand-binding site.
TLS Online TPP Program

#Question id: 33359

#Unit 1. Molecules and their Interaction Relevant to Biology

The protein calcineurin binds to the protein calmodulin with an association rate of 8.9 X103 M-1s-1 and an overall dissociation constant, Kd, of 10 nM. The dissociation rate, kd
TLS Online TPP Program

#Question id: 33360

#Unit 1. Molecules and their Interaction Relevant to Biology

a. HbS (sickle-cell Hb): substitutes a Val for a Glu on the surface
b. Hb Cowtown: eliminates an ion pair involved in T-state stabilization
c. Hb Memphis: substitutes one uncharged polar residue for another of similar size on the surface
d. Hb Bibba: substitutes a Pro for a Leu involved in an α helix

Which Hb variant least likely to cause pathological symptoms
TLS Online TPP Program

#Question id: 33361

#Unit 1. Molecules and their Interaction Relevant to Biology

a. Hb Cowtown: eliminates an ion pair involved in T-state stabilization
b. Hb Milwaukee: substitutes a Glu for a Val
c. Hb Providence: substitutes an Asn for a Lys that normally projects into the central cavity of the tetramer
d. Hb Philly: substitutes a Phe for a Tyr,

Which Hb variant will not bind to BPG
TLS Online TPP Program

#Question id: 33362

#Unit 1. Molecules and their Interaction Relevant to Biology

a. Hb Cowtown: eliminates an ion pair involved in T-state stabilization
b. Hb Milwaukee: substitutes a Glu for a Val
c. Hb Providence: substitutes an Asn for a Lys that normally projects into the central cavity of the tetramer
d. Hb Philly: substitutes a Phe for a Tyr

Which Hb variant will have changed pI as compared to HbA
TLS Online TPP Program

#Question id: 33363

#Unit 1. Molecules and their Interaction Relevant to Biology

An antibody binds to an antigen with a Kd of 5 X10-8 M. At what concentration of antigen will θ be 0.2