Can someone please explain me what does the answer options mean and why they are correct or wrong.
Answer is B(1&3).
Answer is B? Did you find a non-A form?
I found the paper on the official Admission testing website and yes the answers are in the Non-A form or you can say they are shuffled:)
Mind sending me a copy and the answer sheet? I will use it for our class, thank you!
I researched on it and apparently it’s because it’s found on the “sex determining” region of the Y chromosome and it is the key switch which provides instructions for making a protein called the sex-determining region Y protein. This protein is involved in male-typical sex development and follows a certain pattern based on the individual’s chromosomes so maybe 1 does make sense.
Hey! Here’s my explanation. First, let’s work with what the questions says: “The SRY gene is normally located on the human Y chromosome, this gene initiates the development of male characteristics”. Ok, so we have a gene in a chromosome that leads to the formation of “A” (I simplified it so that it’s easier to understand the statements and not to fall into the traps)
- “Insertion of the SRY gene into an X chromosome of a female zygote could give it male characteristics” This is a “Is this possible? / Could this happen?” type of question. Its asking if we could insert the gene into a chromosome and form “A”. This is correct because why not? It could happen, It’s a possibility.
- “A sperm cell arising from incorrect division, which has a functional SRY gene, could give rise to a female with a sex chromosome trisomy following fertilization with a normal ova” This was quite confusing when I first saw it, but we you don’t “assume” that the result of that incorrect division is the formation of diploid sperm cell, it totally makes sense why this statement is wrong. It’s telling you that the result of this incorrect division is having a functional SRY gene. So if a sperm with a functional SRY gene and a normal ova joins, a trisomy cant be produced.
- “During meiosis, crossing over could result in the formation of “X” sperm with the SRY gene, which could cause male characteristics after fertilisation” Here Cambridge wants to trap us with the part "the formation of “X sperm”, by confusing us with the letter X. It doesn’t refers to the X chromosome, but an “X” number of sperm cells. So this statement is correct: meiosis result in a number of “X” sperm cells with this gene, triggering male characteristics. Hope this is helpful
Thank you so much for taking the time and explaining it so clearly it indeed helps a lot:)
Thanks to you! I’m happy to hear that it was useful