Which of the following apply to fibronectins? Please select all that apply.

a) They are disulphide linked dimers, with each polypeptide composed of a number of binding domains joined together by short flexible segments.

b) They have an essential role in linking the extracellular matrix to its underlying cells.

c) Like integrins, fibronectins are directly connected to the cytoskeleton.

d) They participate in 'inside out' and 'outside in' signalling mechanisms.

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#Question id: 33357

#Unit 1. Molecules and their Interaction Relevant to Biology

Protein A has a binding site for ligand X with a Kd of 10^-6 µM. Protein B has a binding site for ligand X with a Kd of 10^-9 µM. Which statement is incorrect?

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

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#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