Question

1. what is the calcareous opening that functions as a pressure-equalizing value in echinoderms?

a)ampullae

b)madreporite

d)podium

e)tube feet

2)which of the following crosses would result in the greatest diversity of genotypes at the A-locus on the offspring population?

a)AA xaa

b) Aa x Aa

c) AA x AA

d)aa x aa

e) Aa x AA

3)In a novel experiment a botanist manages to fuse the genome of endosperm form a corn kernel with a single sperm form the pollen grain. what is the expected ploidy level of the resulting tissue?

a)n

b)2n

c)3n

d)4n

e)5n

Answer 1

1. Option b is correct, Madreporite

Madereporite is a calcareous opening present on the aboral surface of the echinoderms. It filters the water entering into the water vascular system and also functions as a pressure equalising valve.

2. option b is correct, Aa X Aa

cross Aa X Aa

	A	a
A	AA	Aa
a	Aa	aa

Three genotypes: AA, Aa, aa

Option a:  AA X aa

one genotype: Aa

option c: AA X AA

one genotype: AA

option d: aa X aa

one genotype: aa

option e : Aa X AA

Two genotypes : Aa and AA

3. option d is correct, 4n

In angiosperms endosperm is produced as a result of triple fusion hence, it is triploid. Sperm is haploid in nature. Fusion of endosperm genome with a single sperm would result in a tetraploi cell.

Endosperm (3n) X sperm (n)

Resulating cell = 4n