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TLS Online TPP Program

#Question id: 5647

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

Based on the data in the graph, which of the following conclusions is supported?

#Unit 5. Developmental Biology

  1. Plastic beads will bind to sperm from both species of sea urchin.

  2. ERB1 prevents S. franciscanus sperm from binding the beads.

  3. Sperm from S. purpuratus bind to beads only if ERB1 is present.

  4. S. franciscanus and S. purpuratus are actually the same species.

More Questions
TLS Online TPP Program

#Question id: 2710

#Unit 2. Cellular Organization

Which of the following most accurately describes a retrotransposon?
TLS Online TPP Program

#Question id: 5836

#Unit 8. Inheritance Biology

Nonreciprocal recombination, or ___, results from DNA repair synthesis that occurs during the recombination process.
TLS Online TPP Program

#Question id: 12996

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following is incorrect regarding to α-helix
a) In the α helix, the first four NH groups and last four CO groups will normally lack backbone  hydrogen bonds.
b) the length of an amino acid in α-helix reduced almost 3 times than linear structure.
c) the frequent occurrence of Pro and Gly residues favour α-helix formation.
d) dihedral (ϕ and ψ) angle should be close to -57 and -47.
TLS Online TPP Program

#Question id: 28289

#Unit 5. Developmental Biology

 which of the following enzyme that cleaves the proteins linking the vitelline envelope to the cell membrane ?
TLS Online TPP Program

#Question id: 31039

#Unit 4. Cell Communication and Cell Signaling

Phosphorylation of tyrosine in activation loop leads to a conformational change in the activation loop that unblocks the kinase active site for either ATP or the substrate by:
Reducing the Kd 
Increasing the Kd
Reducing the affinity
Increasing the affinity

Which of the following combination is correct?