If an individual has the alleles, Ss, what is its gametic composition?

Question

only S

s only

half of gametes will be SS and half will be ss

half of gametes will be S and half will be s

Answer 1

The law of segregation says that these alleles will segregate when gametes are formed -- they will go into separate gametes.

So from parent Ss, half of the gametes will have one of the alleles, S, and half of the gametes will have the other allele, s.

The last answer is correct.

Answer 2

First, you have one trait you inherited from Dad and one you inherited from Mom. That is what an allele is, an alternate form of a trait. Now you have to make gametes (eggs or sperm) so you can reproduce. You have to get rid of one of the alleles so your sperm can get together with the egg and make a baby. That way, the baby can get one allele from you and one from your partner.
You inherited big S from Dad and little s from Mom (example). You have to get rid of one S for your gametes, so SS and ss is wrong or your kids will have Downs syndrome. Your gametes will have an equal chance of getting the big S or the little s (that's what happens when cells divide, they divvy up the chromosomes that have the S and the s). So you should now know the answer.

Answer 3

half of gamete will be S and half will be s