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: 9279

#Unit 6. System Physiology – Plant

During the normal functioning of the photosynthetic system, the chemical reactions in which water is oxidized to oxygen, NADP+ is reduced to NADPH, and ATP is formed almost all the reactions up to NADP+ reduction take place in

TLS Online TPP Program

#Question id: 9285

#Unit 6. System Physiology – Plant

Non-O2-evolving (anoxygenic) organisms, contain only a single photosystem such as

TLS Online TPP Program

#Question id: 9583

#Unit 6. System Physiology – Plant

 A mechanism known as the Q cycle accounts for most of the observations in which structure and reactions of plastoquinone that operate in,

TLS Online TPP Program

#Question id: 9585

#Unit 6. System Physiology – Plant

In light reaction the reaction centre of PSII  receives electron from water molecules by splitting into oxygen, If 5 oxygen molecules evolved per 50 quanta was

absorbed then what is the quantum yield?

TLS Online TPP Program

#Question id: 9589

#Unit 6. System Physiology – Plant

The physical mechanism by which excitation energy is conveyed from the chlorophyll that absorbs the light to the reaction centre, By this mechanism the excitation energy is transferred from one molecule to another by a nonradioactive process, this mechanism is known as

TLS Online TPP Program

#Question id: 9595

#Unit 6. System Physiology – Plant

The process is that the absorbed photon causes an electron rearrangement in the reaction centre chlorophyll, followed by an electron transfer process in which part of the energy in the photon is captured in the form of