TLS Online TPP Program

#Question id: 5648


Use the following information to answer the question. In order to test how sea urchin sperm bind to eggs, scientists isolated the egg receptor protein that binds to the sperm acrosomal protein called bindin. Plastic beads were coated with egg receptor for bindin (ERB1) from eggs of the sea urchin Strongylocentrotus purpuratus, and then the beads mixed with sperm from S. purpuratus or from the related species, S. franciscanus. The researchers counted how many sperm were bound to each bead. The results are shown in the graph below. Treatments:

A: S. purpuratus sperm mixed with S. purpuratus ERB1 beads

B: S. purpuratus sperm mixed with beads containing no ERB1 protein

C: S. franciscanus sperm mixed with S. purpuratus ERB1 beads

D: S. franciscanus sperm mixed with beads containing no ERB1 protein

 What is a broader implication from the observations of the experiment?

#Unit 5. Developmental Biology
  1. In sea urchins, fertilization of eggs by sperm is dependent upon species-specific protein interactions.

  2. Only some species of sea urchins use receptor proteins on their eggs to bind sperm.

  3. Protein-coated plastic beads should not be used to test sperm binding to eggs.

  4. S. franciscanus is probably not a sea urchin, but must be some other type of organism.

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TLS Online TPP Program

#Question id: 23751

#Unit 1. Molecules and their Interaction Relevant to Biology

Which one of the following is always associated with 'Justice'?

TLS Online TPP Program

#Question id: 743

#Unit 1. Molecules and their Interaction Relevant to Biology

Glycophorin, an integral membrane protein, has a single transmembrane alpha helix. Which of the following idealized hydropathy plots most likely represents the transmembrane nature of glycophorin?

TLS Online TPP Program

#Question id: 742

#Unit 1. Molecules and their Interaction Relevant to Biology

Match the following

ConformationPhiPsiOmega
A. Alpha helixI. -57P. -47X. 180
B. B sheetII. -135Q. +135Y. 0
C. Polyproline IIII. -83R. +158
D. Polyproline IIIV. -78S. +149

TLS Online TPP Program

#Question id: 741

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of following statements are INCORRECT about secondary structure of proteins

A. Long block of Glu residues segment of the chain will not form an alpha helix at pH 7.0 but it ll take helical confirmation below its pKR value

B. Long block of Lys residues segment of the chain will not form an alpha helix at pH 7.0 but it ll take helical confirmation above its pKR value

C. Long block of Ala residues segment of the chain will not form an alpha helix at pH 7.0 but it ll take helical confirmation below its pKR value

D. Histidine side chain remain uncharged over pH range 3-6

TLS Online TPP Program

#Question id: 740

#Unit 1. Molecules and their Interaction Relevant to Biology

The conformation of the backbone of a polypeptide is described completely by the angle(s) of rotation about which bond(s)?

TLS Online TPP Program

#Question id: 739

#Unit 1. Molecules and their Interaction Relevant to Biology

What is true about the rotation about bonds in a protein backbone?