Biology · Human Reproduction · NEET
A sperm is made of four parts in order: head, neck, middle piece and tail. NCERT lists them exactly this way. A plasma membrane wraps the whole sperm body. Remember the order HNMT because NEET Match-type questions test each part with its function.
The middle piece contains numerous mitochondria. These mitochondria produce the energy (ATP) needed to move the tail. This is a very common NEET trap: mitochondria are in the MIDDLE PIECE, not the head or tail. The tail only uses this energy to move.
No. The head is the whole front region that holds the elongated haploid nucleus (the genetic material). The acrosome is only a small cap-like structure covering the ANTERIOR part of the head. The acrosome is filled with enzymes that help the sperm penetrate the ovum during fertilisation.
The middle piece makes energy. It possesses numerous mitochondria that produce energy for the movement of the tail. So its function is energy supply, not motility itself. In NEET matching questions: middle piece pairs with 'energy', and tail pairs with 'motility'.
The neck is a very short region between the head and middle piece. It contains the centrioles (proximal and distal). NCERT does not describe the neck in detail, so for NEET just remember: neck = centrioles, and it connects the head to the middle piece.
The tail gives motility. The tail lashes or beats to move the sperm forward, which is essential for reaching the ovum. But the energy for this movement comes from the mitochondria in the middle piece. So: tail = motility, middle piece = energy.
Match List-I and List-II. List-I (A. Head; B. Middle piece; C. Acrosome; D. Tail) List-II (I. Enzymes; II. Sperm motility; III. Energy; IV. Genetic material) Choose the correct answer from the options given below:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
A plasma membrane envelops the whole body of the sperm, from head to tail. NCERT states this directly.
NCERT says the middle piece possesses numerous mitochondria. It does not give an exact number, so for NEET just remember 'numerous mitochondria = energy for the tail'.
The acrosome is filled with enzymes that help in the fertilisation of the ovum. These enzymes help the sperm break through the coverings of the egg.
NCERT: at least 60 per cent of sperms must have normal shape and size, and at least 40 per cent must show vigorous motility. A male ejaculates about 200 to 300 million sperms per coitus.
The sperm head contains an elongated haploid nucleus, so the sperm is haploid. It is formed by meiosis during spermatogenesis and carries half the chromosome number.
