Sperm Anatomy

Q.

Draw a labelled diagram of sperm.

Q.

How many sperms are formed from a secondary spermatocyte?

Q.

What happens during the acrosome reaction?

Q. Draw a diagram of a mature human sperm. Label any three parts and write their functions. [3]

Q. (a) Why is the follicular phase in the menstrual cycle also called proliferative phase?
(b) Explain the events that occur in the Graafian follicle during ovulation? [5]

Q. Which one of the following statements about human sperm is correct?

1. Acrosome has a conical point structure used for piercing and penetrating the egg resulting in fertilisation
2. The sperm lysins in the acrosome dissolve the egg envelope facilitating fertilisation
3. Acrosome serves as a sensory structure leading the sperm towards the ovum
4. Acrosome serves no particular function

Q. During spermatogenesis, how many primary spermatocytes will form 800 spermatozoa?

1. 400
2. 200
3. 800
4. 100

Q.

Is a sperm cell haploid or diploid?

Q. Receptors for sperm binding in mammals are present on:

1. Vitelline membrane
2. Corona radiata
3. Zona pellucida
4. Perivitelline space

Q.

The middle piece of the sperm contains:

1. Mitochondria

2. Proteins

3. Nucleus

4. Centriole

Q. Arrange the following events in the sequence as they would occur during fertilisation.

I. Metabolic activation
II. Formation of reception cone
III. Penetration of oocyte
IV. Amphimixis
V. Block to polyspermy

1. I→ II→ III→ IV→ V
2. V→ III→ I→ IV→ II
3. III→ II→ I→ V→ IV
4. IV→ III→ II→ I→ V

Q. Match the following and choose the correct option.

$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{A. Head}& \text{1. Enzymes}\\ \text{B. Middle Piece}& \text{2. Sperm motility}\\ \text{C. Acrosome}& \text{3. Energy}\\ \text{D. Tail}& \text{4. Genetic material}\end{array}$

1. $\begin{array}{cccc}A-2& B-4& C-1& D-3\end{array}$
2. $\begin{array}{cccc}A-4& B-3& C-1& D-2\end{array}$
3. $\begin{array}{cccc}A-4& B-1& C-2& D-3\end{array}$
4. $\begin{array}{cccc}A-2& B-1& C-3& D-4\end{array}$

Q. Which of the following is/are responsible for the formation of the ootid?

1. The fusion of male and female pronuclei
2. The entry of the sperm into the cytoplasm of the primary oocyte
3. The release of cortical vesicles outside the plasma membrane of the oocyte
4. The entry of the sperm into the cytoplasm of the secondary oocyte

Q. Layer of cells immediately surrounding the ovum but outside the zona pellucida is called as

1. germinal epithelium
2. corona radiata
3. theca externa
4. perivitelline space

Q. (a) Explain the following phases in the menstrual cycle of a human female :
(i) Menstrual phase
(ii) Follicular phase
(iii) Luteal phase

(b) A proper understanding of menstrual cycle can help immensely in family planning. Do you agree with the statement ? Provide reasons for your answer. [5]

Q. What happens during fertilization in humans after many sperms reach close to the ovum?

1. Secretions of acrosome helps one sperm enter cytoplasm of ovum through zona pellucida
2. All sperms except the one nearest to the ovum lose their tails
3. Cells of corona radiate trap all the sperms except one
4. Only two sperms nearest the ovum penetrate zona pellucida

Q. The head of sperm contains the nucleus having a haploid set of chromosomes in a

1. 
   compact and inactive state
2. 
   compact and active state
3. 
   rate and inactive state
4. 
   rare and active state

Q. In humans, at the end of the first meiotic division, the male germ cell differentiate into the

1. spermatids
2. spermatogonia
3. primary spermatocyte
4. secondary spermatocyte

Q.

What are the three events that must take place for fertilization to occur when spermatozoa encounter an oocyte?

Q.

What happens after 3 days in the process of spermatogenesis

Q. Match the following terms with their respective definitions.

1. A→(iv), B→(iii), C→(i), D→(ii)
2. A→(ii), B→(i), C→(iv), D→(iii)
3. A→(i), B→(ii), C→(iv), D→(iii)
4. A→(iii), B→(i), C→(iv), D→(ii)

Q.

The genetic information is carried by which part of the sperm?

1. Tail

2. Middle piece

3. Head

4. None of these

Q. The enzymes that dissolve the membrane
enveloping the ovum and help sperm to enter the ovum are:

1. Sperm lysins
2. Inhibin
3. Both a and b
4. Spectrin

Q.

Choose the correct option with respect to the assertion and reason given.

Assertion [A]: Sperm formed is stored in the seminal vesicle.

Reason [R]: Ejaculation takes place after the addition of secretions from accessory glands.

1. [A] is true and [R] is false.

2. [A] is false and [R] is true .

3. Both [A] and [R] are true and [R] is a correct explanation to [A].

4. [A] is true and [R] are true but, [R] is not a correct explanation to [A].

Q.

There is no cell division involved in

1. Spermatogenesis

2. Oogenesis

3. Embryogenesis

4. Spermiogenesis

Q. Which among the following hormones is secreted by the corpus luteum?

1. Estrogen
2. Progesterone
3. LH
4. FSH

Q. Draw a neat labelled diagram of human sperm.

Q.

Sperm enters the egg from

Animal pole

Vegital pole

Micropyle

Megapyle

Q.

The cell organelle(s) present in a mature sperm is/are

1. Nucleus

2. Acrosome

3. All of the above

4. Mitochondria

5. Centriole

Q.

Which of the following represents a condition where the motility of sperms is highly reduced?

1. Azoospermia

2. Polyspermy

3. Asthenospermia

4. Oligospermia