ZOO501P Final Term Past Papers by Kainat Alvi

DEVELOPMENTAL BIOLOGY (ZOO501P) · CURRENT FINAL TERM PAPER FALL 2023(17-FEB) · SHORT QUESTIONS(3) · 1. Label the structure of sperm

Q2. What happened if sperm lack the centriole?

If a sperm lacks the centriole, it can impact the process of fertilization. The centriole is crucial for the formation of the microtubules that make up the sperm's tail and are essential for movement. Without a functional centriole, the sperm may experience difficulty in swimming toward the egg. Additionally, the centriole plays a key role in the formation of the mitotic spindle during fertilization, aiding in the proper division of genetic material. Therefore, a lack of centriole may result in reduced fertility or hinder the sperm's ability to fertilize an egg successfully.

3. Acrosomal reaction and cortical granules reaction

❖ Acrosomal Reaction:

The acrosomal reaction is a process in which a sperm releases enzymes from a structure called the acrosome. This reaction helps the sperm penetrate the outer layer of the egg, known as the zona pellucida, allowing fertilization to occur.

❖ Cortical Granules Reaction:

The cortical granules reaction is a protective mechanism that occurs in the egg after fertilization. It involves the release of special vesicles, called cortical granules, which prevent additional sperm from binding to the egg. This reaction ensures that only one sperm successfully fertilizes the egg, maintaining the genetic integrity of the resulting embryo.

4. Differences between the white and yellow yolk of eggs.

❖ Yellow yolk

A major source of vitamins, minerals, almost half of the protein, and all of the fat and cholesterol. The yolk contains less water and more protein than the white, some fat, and most of the vitamins and minerals of the egg. These include iron, vitamin A, vitamin D, phosphorus, calcium, thiamine, and riboflavin. The yolk is also a source of lecithin, an effective emulsifier. Yolk color ranges from just a hint of yellow to a magnificent deep orange, according to the feed and breed of the hen.

❖ White yolk

Also known as, the latebra is an area of white yolk located in the center of the yolk. It is lower in fat and therefore stands out as a bright white area in many Magnetic Resonance Images. The specific function of the latebra is uncertain but it may act as a central structure around which the additional layers of the yolk are formed.

5. Describe the differences between an ovum and a zygote.

❖ Ovum

An ovum, also known as an egg cell, is the female reproductive cell. It is produced in the ovaries and released during ovulation. The ovum is a large cell that contains genetic material and is capable of being fertilized by a sperm cell.

❖ Zygote

On the other hand, a zygote is the result of the fusion of an egg cell (ovum) and a sperm cell. It is the earliest stage of development after fertilization occurs. The zygote contains a complete set of genetic material from both the mother and father, and it marks the beginning of a new individual's development.

Q6. What is ovaprim and why it is used in breeding of fishes?

Ovaprim is one of the most popular and effective solutions to stimulate the maturation of male and female brood fish.

Ovaprim is a hormone-based fish spawning agent that is used to help breed fishes. When injected into female fishes, Ovaprim helps stimulate the release of eggs (ova) from their ovaries. It makes sure that the breeding happens at the right time. It also helps in synchronizing the spawning process, making it easier for fish farmers to control and manage breeding. Fish farmers use Ovaprim to increase the success rate of breeding and to produce more fish for various purposes, like stocking ponds or supplying fish for consumption.

Q7. Which are the three dosage of ovaprim were tested in this studies for females and males?

Three dosages of Ovaprim were tested in this study:

For Females,

o 0.3 ml kg -1 body weight (BW), o 0.5 ml kg 1BW, o and 0.7 ml kg -1BW;

For Males,

o 0.15 ml kg -1BW. o The broodfish in control groups were injected with physiological solution (0.9% NaCL) at the dosage of 0.25 ml kg -1BW.

8. How Trichostrongylus infect human

Infections occur via ingestion of infective larvae from contaminated vegetables or water.

Trichostrongylus spp are a type of parasitic worms that can infect humans. The primary mode of infection is through the ingestion of contaminated food or water. When humans consume food or water that is contaminated with the larvae of Trichostrongylus spp, the larvae can enter the digestive system. From there, they migrate into the small intestine, where they attach themselves to the intestinal lining and start feeding on blood. This can lead to symptoms such as abdominal pain, diarrhea, and anemia.

Q9. Which nematode was most prevalent according to the observation?

The most prevalent nematode was Trichostrongylus retortaeformis (50%) (Fig. 6.1), followed by Trichuris leporis found 18 (21.42 %) (Fig 6.2) animals and Passalurus ambiguus in 4 (4.76 %).

10.

Observation of nematode?

The most prevalent nematode was Trichostrongylus retortaeformis (50%) (Fig. 6.1), followed by Trichuris leporis found 18 (21.42 %) (Fig 6.2) animals and Passalurus ambiguus in 4 (4.76 %).

Mixed infections (Fig. 3) were significantly more common than single infections .

11. Role of cilia in oviduct?/ Role of cilia in mammalian cleavage.

In Mammalian cleavage, Cilia in the oviduct push the embryo toward the uterus. Cilia in the oviduct play a crucial role in guiding the egg from the ovary to the uterus. These tiny hair-like structures create a coordinated wave-like motion, helping to move the egg along the oviduct. Additionally, cilia assist in transporting nutrients and providing a suitable environment for fertilization to occur.

12.

Fertilization In Mammals

In mammals, fertilization occurs internally. During sexual reproduction, the male releases sperm into the female reproductive system through sexual intercourse. The sperm then travel through the female's reproductive tract, eventually reaching the fallopian tubes, where they may encounter an egg.

If a sperm successfully penetrates the egg's outer layer, fertilization takes place. This results in the fusion of the genetic material from the sperm and the egg, forming a single cell called a zygote. The zygote then begins to divide and develop, eventually implanting itself into the uterus and continuing its growth into an embryo.

13.

Where does fertilization occur in mammals what follow after shortly?

In mammals, fertilization typically occurs in the fallopian tubes, also known as the oviducts. After fertilization takes place, the fertilized egg, or zygote, undergoes a process called cleavage, where it starts dividing into more cells. This forms a structure called a blastocyst. The blastocyst then travels through the fallopian tubes towards the uterus. Once it reaches the uterus, it implants itself into the uterine lining, a process known as implantation. After implantation, the embryo continues to develop and grow within the uterus.

14.

What happen when mitosis occur during gamete formation?

During gamete formation, mitosis does not occur. Instead, a special type of cell division called meiosis takes place. Meiosis involves two rounds of cell division, resulting in the formation of four haploid cells called gametes. These gametes, such as sperm cells in males and egg cells in females, contain half the number of chromosomes compared to the parent cell. This reduction in chromosome number is crucial for sexual reproduction, as it ensures that when the gametes fuse during fertilization, the resulting embryo will have the correct number of chromosomes.

15.

In what situation fingertips is used in amnesia victim and unknown deceased individuals?

In situations involving amnesia victims or unknown deceased individuals, fingerprints can be used for identification purposes. Fingerprints are unique patterns formed by ridges and furrows on the skin of our fingertips. These patterns are highly individualistic, meaning that no two people have the exact same fingerprints. Law enforcement agencies and forensic experts often rely on fingerprints to identify individuals, as they can be compared to a database of known fingerprints. This helps in determining the identity of someone who may have lost their memory or in cases where the identity of a deceased person is unknown.

16.

How can fingerprints be used to identify unknown deceased in disasters?

Fingerprints can be used to identify unknown deceased individuals in disasters through a process called fingerprint analysis or comparison. Each person has unique patterns on their fingertips, and these patterns can be captured and stored in a database. When an unidentified body is found, fingerprints can be taken from the deceased and compared to the existing fingerprint records to see if there is a match. This method is highly reliable and widely used in forensic science to help identify individuals in various situations, including disasters.

LONG QUESTIONS(5)

1) Structure of Sperm

The male gamete (sperm) is small and motile and only contributes the male’s haploid nucleus to the zygote. A typical human spermatozoon can be divided into three sections,

1. Head,
2. Mid-piece
3. Tail

Head region: The head region contains three structures,

o A haploid nucleus: The haploid nucleus contains the paternal DNA (this will combine with maternal DNA if fertilization is successful) o An acrosome cap: The acrosome cap contains hydrolytic enzymes which help the sperm to penetrate the jelly coat of the egg o Paired centrioles: The centrioles are needed by a zygote in order to divide (egg cells expel their centrioles within their polar bodies)

Mid-piece: The mid-piece contains high numbers of mitochondria which provide the energy (ATP) needed for the tail to move

Tail: The tail (flagellum) is composed of a microtubule structure called the axoneme, which bends to facilitate movement.

Q2. Diff b/w zona pellucida, corona radiata and follicular cells?

Zona Pellucida: The zone pellucida (jelly coat) The zona pellucida is a glycoprotein matrix which acts as a barrier to sperm entry.

Corona radiate: The corona radiata is an external layer of follicular cells which provide support and nourishment to the egg cell.

Follicular cells: The follicle is an ovarian structure with two major functions, namely, the production of hormones and growth of oocytes capable of being fertilized. (400,000 follicles)

3. Distinguished between exterior albumin and middle albumen.