Question

External Fertilization. Describe three mechanisms by which sea urchins can ensure species specificity of sperm-egg binding. Include examples of the genes/proteins, which were discussed in class and in the textbook, that are involved in each mechanism. PLEASE EXPLAIN IN A PARAGRAPH OR TWO

Answer 1

Answer :

Sea urchins have external fertilization, that is outside the body. So to maintain species specificity, they employ different strategies. First strategy is synchronized spawning. By this sperms are released in a synchronous manner with egg release by female.

There is chemotaxis which lead sperm to species specific eggs. Once sperm find chemoattractant it changes swimming direction with its flagella.

Sperm has got an adhesive protein called bindin. This increases specificity for sperms for the corresponding egg only. There is a complementary receptor on the egg for specific binding to the sperm.