Oogenesis

Question 1

What is oogenesis?

Answer 1

Oogenesis is the process of gametogenesis that shapes and develops female gametes, also called ova or eggs, in the ovaries.

Question 2

When does oogenesis begin?

Answer 2

Oogenesis begins before birth.

Question 3

What happens to oogenesis after it begins?

Answer 3

After oogenesis begins, its development is suspended until puberty.

Question 4

When does the development of oogenesis resume?

Answer 4

Development of oogenesis resumes with ovulation.

Question 5

When is the final step of oogenesis, meiosis I, completed?

Answer 5

The final step of oogenesis, meiosis I, is completed only if fertilization occurs.

Question 6

What is the role of the germinal vesicle in the female reproductive cell?

Answer 6

The germinal vesicle, or nucleus, contains the female’s genetic material, which, along with the genetic material in the sperm cell, determines the inherited characteristics of the offspring.

Question 7

Where is the germinal vesicle located in the female reproductive cell?

Answer 7

The germinal vesicle is located in the nucleus of the female reproductive cell.

Question 8

How does the germinal vesicle contribute to inheritance?

Answer 8

The germinal vesicle contributes to inheritance by holding the female’s genetic material, which combines with the genetic material from the sperm cell to determine the offspring’s characteristics.

Question 9

Why is the germinal vesicle important in reproduction?

Answer 9

This question focuses on the significance of the germinal vesicle in the context of reproduction, emphasizing its role in the inheritance process.

Question 10

What is the primary function of the germinal spot, also known as the nucleolus, in the cell’s nucleus?

Answer 10

The primary function of the germinal spot, or nucleolus, is to produce and assemble the cell’s ribosomes.

Question 11

What role does the nucleolus play in the transcription process?

Answer 11

The nucleolus is where ribosomal RNA genes are transcribed.

Question 12

Where are ribosomes transported after they are assembled in the nucleolus?

Answer 12

After being assembled in the nucleolus, ribosomes are transported to the cell cytoplasm.

Question 13

What is the function of ribosomes once they are in the cell cytoplasm?

Answer 13

Once in the cell cytoplasm, ribosomes serve as the sites for protein synthesis.

Question 14

What is the role of the cytoplasm (or ooplasm) in a cell?

Answer 14

The cytoplasm, also known as ooplasm, is a gel-like substance that holds all the cell’s internal structures, called organelles. It is where all the cell’s activities occur to keep it alive and functioning properly.

Question 15

What is one of the key functions of mitochondria within the cytoplasm?

Answer 15

Mitochondria, which are structures within the cytoplasm, supply most of the energy for the cell.

Question 16

What does the cytoplasm contain that is essential for cellular function?

Answer 16

The cytoplasm contains all the cell’s organelles, which are essential for various cellular functions and activities.

Question 17

What is the perivitelline space?

Answer 17

The perivitelline space is the area between the zona pellucida (outer layer) and the cell membrane of an oocyte or fertilized ovum.

Question 18

Why is the perivitelline space clinically important?

Answer 18

The perivitelline space is clinically important because it is where the polar body, which is a product of meiosis, lodges after the cell division process.

Question 19

Where does the polar body stay after meiosis in relation to the oocyte?

Answer 19

After meiosis, the polar body stays in the perivitelline space, which is between the zona pellucida and the cell membrane of the oocyte.

Question 20

What is the zona pellucida?

Answer 20

The zona pellucida is a thick outer layer that surrounds all mammalian eggs and early embryos before they implant.

Question 21

What role does the zona pellucida play during oogenesis?

Answer 21

During oogenesis, the zona pellucida helps with communication between the egg cells (oocytes) and the surrounding follicle cells.

Question 22

How does the zona pellucida protect the egg and embryo?

Answer 22

The zona pellucida protects the egg and embryo during their development by acting as a barrier.

Question 23

What function does the zona pellucida serve in relation to sperm?

Answer 23

The zona pellucida regulates how ovulated eggs interact with sperm, helping to manage fertilization.

Question 24

When does the zona pellucida’s protective role occur?

Answer 24

The zona pellucida’s protective role occurs throughout the development of the egg and embryo, and also during fertilization.

Question 25

What surrounds the egg and consists of two or three layers of cells from the follicle?

Answer 25

The corona radiata surrounds the egg and consists of two or three layers of cells from the follicle.

Question 26

What is the main purpose of the corona radiata?

Answer 26

The main purpose of the corona radiata is to supply vital proteins to the egg cell.

Question 27

To what part of the egg is the corona radiata attached?

Answer 27

The corona radiata is attached to the zona pellucida, which is the outer protective layer of the egg.

Question 28

What is a polar body, and how did it get its name?

Answer 28

A polar body is a small haploid cell that forms during oogenesis, named for its position at the pole or edge of the egg.

Question 29

When is a polar body formed, and what process is it associated with?

Answer 29

A polar body is formed during oogenesis, the process of egg cell development.

Question 30

Does a polar body have the ability to be fertilized?

Answer 30

No, a polar body generally does not have the ability to be fertilized.

Question 31

What is the vitelline membrane, and where is it located?

Answer 31

The vitelline membrane, also called the vitelline envelope, is a structure surrounding the outer surface of the plasma membrane of the ovum.

Question 32

What is the primary composition of the vitelline membrane?

Answer 32

The vitelline membrane is mostly composed of protein filaments and receptors.

Question 33

What is the role of the receptors in the vitelline membrane?

Answer 33

The receptors in the vitelline membrane are required for sperm binding.

Question 34

STAGES OF CELLS IN OOGENESIS:

Answer 34

• OOGONIUM
• PRIMARY OOCYTE
• SECONDARY ООСУТЕ
• OOTIDS
• OVUM

Question 35

What is an oogonium, and what role does it play in female reproductive development?

Answer 35

An oogonium is an immature diploid female gamete found in the ovary that gives rise to oocytes through mitotic divisions.

Question 36

What happens to oogonia during the early stage of fetal development?

Answer 36

During the early stage of fetal development, oogonia go through mitosis, producing primary oocytes that are arrested at prophase 1.

Question 37

What happens to most oogonia before birth?

Answer 37

Most oogonia degenerate before birth, and only a few enter the first meiotic division as primary oocytes.

Question 38

At what stage of the cell cycle does the primary oocyte stop developing, and when does this occur?

Answer 38

The primary oocyte stops developing at the Prophase of Meiosis I, and it remains arrested in this phase until the individual reaches sexual maturity.

Question 39

What happens to the primary oocyte when an individual reaches puberty?

Answer 39

When an individual reaches puberty, the primary oocyte completes Meiosis I and forms a secondary oocyte.

Question 40

How long does the primary oocyte remain arrested in the Prophase of Meiosis I?

Answer 40

The primary oocyte remains arrested in the Prophase of Meiosis I from the time it enters this stage until the individual reaches sexual maturity, which is at puberty.

Question 41

What is a secondary oocyte, and what does it become after completing all cell divisions?

Answer 41

A secondary oocyte is the oocyte that results after meiosis I is completed. It will eventually give rise to an ootid and, upon completion of all cell divisions, becomes an ovum.

Question 42

At what stage of meiosis II is the secondary oocyte blocked, and what event is necessary for it to continue?

Answer 42

The secondary oocyte is blocked at metaphase II of meiosis II. It will remain in this stage until fertilization occurs, which allows it to continue the process.

Question 43

What is the significance of the secondary oocyte being blocked at metaphase II?

Answer 43

The significance of the secondary oocyte being blocked at metaphase II is that it pauses in this stage until fertilization, ensuring that the oocyte is ready for the next steps of development only when fertilization is imminent.

Question 44

What is an ootid, and how is it formed?

Answer 44

An ootid is a haploid cell formed after the female gamete has undergone all cell divisions. It is created when the oocyte, which was paused at metaphase of meiosis II, resumes and completes its meiotic division after the sperm successfully enters the cytoplasm of the secondary oocyte.

Question 45

What happens to the oocyte after the sperm enters its cytoplasm?

Answer 45

After the sperm enters the cytoplasm of the secondary oocyte, the oocyte, which was suspended at metaphase of meiosis II, continues its meiotic division, leading to the formation of an ootid and a second polar body.

Question 46

What specific stage of meiosis does the oocyte resume after sperm entry?

Answer 46

The oocyte resumes from the metaphase of meiosis II after the sperm successfully enters its cytoplasm.

Question 47

What is produced alongside the ootid during the completion of meiotic division?

Answer 47

During the completion of meiotic division, the oocyte produces an ootid and a second polar body.

Question 48

What is an ovum, and how does it interact with sperm during fertilization?

Answer 48

An ovum, also called an egg cell, is a non-motile gamete produced by females. During fertilization, it fuses with the motile sperm, resulting in the formation of a zygote.

Question 49

How does the size of an ovum compare to other cells in the body?

Answer 49

An individual ovum is visible to the naked eye and is considered one of the largest single cells in the body.

Question 50

What roles does the ovum play in reproduction?

Answer 50

The ovum carries the set of chromosomes contributed by the female, creates the right environment for fertilization by the sperm, and provides nutrients for the growing embryo.

Question 51

Why is the ovum important in the formation of a zygote?

Answer 51

The ovum is important in the formation of a zygote because it fuses with the sperm during fertilization, contributing the female’s set of chromosomes and ensuring the right environment and nutrients for the developing embryo.

Question 52

What is a polar body, and when does it form?

Answer 52

A polar body is a small haploid cell that forms during the unequal meiotic divisions of the ovum, usually at or near the time of fertilization.

Question 53

How does the division of cytoplasm occur during oogenesis, and what happens to the polar body?

Answer 53

During oogenesis, the cytoplasm divides unevenly after meiosis. The ovum receives most of the cytoplasm, while the polar body gets only a small amount.

Question 54

What happens to the primary polar body after the first meiosis during oogenesis?

Answer 54

After the first meiosis during oogenesis, the primary polar body is produced. It then undergoes a second meiosis simultaneously with the secondary oocyte, resulting in three secondary polar bodies.

Question 55

What eventually happens to the secondary polar bodies produced during oogenesis?

Answer 55

The secondary polar bodies produced during oogenesis eventually die and disintegrate through a process called apoptosis.

Question 56

What is parthenogenesis, and in which species can it occur?

Answer 56

Parthenogenesis is a natural form of asexual reproduction where the growth and development of embryos occur from one gamete without combining with a counterpart gamete. It can occur in some plants, algae, invertebrate animals like nematodes and scorpions, and a few vertebrates such as some fish, amphibians, and reptiles.

Question 57

How does parthenogenesis result in the development of an embryo in animals?

Answer 57

In animals, parthenogenesis results in the development of an embryo from an unfertilized egg cell.

Question 58

What specific process happens during parthenogenesis in some species, and what does it result in?

Answer 58

In some species, the polar body may re-merge with the ovum, resulting in a viable embryo that only has one parent.

Question 59

Describe the role of the polar body in parthenogenesis?

Answer 59

During parthenogenesis, in some species, the polar body can re-merge with the ovum, leading to the creation of a viable embryo without the need for fertilization by a male gamete.