TLS Online TPP Program

#Question id: 5673


Species-specific sperm attraction has been documented in numerous species. In echinoderms, sperm are attracted toward eggs of their species by chemotaxis. Following statements are about chemoattraction-

A. In this process Sperm follows a gradient of a chemical secreted by the egg.

B. These oocytes control only the type of sperm they attract, but not the time at which they attract them.

C. Releasing the chemotactic factor only when the sea urchin egg has completed all of its meiotic divisions .

D. Releasing the chemotactic factor only when the sea urchin egg is in second metaphase of its meiotic division.

E. The mechanisms of chemotaxis differ among species and chemotactic molecules are different even in closely related species.

Which of the following statement are incorrect about this process?

#Unit 5. Developmental Biology
  1. A and D

  2. B and C

  3. C and E

  4. B and D

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#Question id: 14970

#Unit 2. Cellular Organization

A research lab is trying to produce new antibiotics. They come up with drugs that detach the hydrophilic heads from the phospholipids in plasma membranes. This drug

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#Question id: 14971

#Unit 2. Cellular Organization

Bacillus and Clostridium are medically relevant groups of bacteria that characteristically stain 

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#Unit 2. Cellular Organization

Although O side chains are readily recognized by host antibodies, gram negative bacteria may thwart host defenses by 

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#Question id: 14976

#Unit 2. Cellular Organization

Plasmids are not required for host growth and reproduction, although they may carry genes that give their bacterial host a selective advantage. Plasmid genes can render  bacteria 
1. Drug-resistant 
2. Give new metabolic abilities 
3. Make them pathogenic

Which among the following combinations is correct?

TLS Online TPP Program

#Question id: 14977

#Unit 2. Cellular Organization

Careful electron microscopic studies often have shown the nucleoids are present in contact. Thus bacterial DNA is attached to

TLS Online TPP Program

#Question id: 14978

#Unit 2. Cellular Organization

Inclusion bodies are enclosed by a membrane about 2.0 to 4.0 nm thick, which is single-layered and not a typical bilayer membrane. They are 
1. Poly β hydroxybutyrate granules
2. cyanophycin granules
3. Glycogen granules
4. Sulfur granules
5. Gas vacuoles
6. Polyphosphate granules
Which option is having correct combinations?