Chapter 61, Problem 1PL

The ovum and sperm unite and form a diploid cell called the
a. pronucleus.
b. blastocyst.
c. morula.
d. zygote.

Summary Introduction

Introduction: 

Sperm is a male sex cell develop in testis during spermiogenesis where ovum is female sex cell produced in the ovary. Diploid cell means a cell containing two sets of chromosomes where haploid contain a half number of chromosomes.

Answer to Problem 1PL

Correct answer: 

The correct answer is an option (d) The ovum and sperm unite and form a diploid cell called the zygote.

Explanation of Solution

Explanation/justification for the correct answer:

Option (d) The ovum and sperm unite and form a diploid cell called the zygote. when sperm fertilized with female gamete i.e. ovum it becomes a zygote. Sperm and ovum are haploid cells when it fuses together it becomes a diploid cell. So, the correct answer is an option (d).

Explanation for incorrect answer: 

Option (a) The ovum and sperm unite and form a diploid cell called the pronucleus. Pronucleus is actually sperm or nucleus before fertilization. So, this is an incorrect option.

Option (b) The ovum and sperm unite and form a diploid cell called the blastocyst. The blastocyst is the early development of an organism. So, this is an incorrect answer.

Option (c) The ovum and sperm unite and form a diploid cell called a morula. This option is incorrect because it is an earlier stage of the embryo. So this option is incorrect.