During the S-phase of interphase, DNA replication takes place within the entangled chromatin fibers. As a result of DNA replication, each chromosome in the cell is composed of two identical sister chromatids held together at the centromere.

During prophase of mitosis, the chromatin fibers condense and become visible as thick, distinct chromosomes. This condensation is necessary to ensure that the replicated chromosomes can be separated correctly during cell division. At this stage, the sister...

Mitosis is a type of cell division where a mature mother cell divides to form two daughter cells which are identical to each other as well as with mother cell.

The importance of mitosis are as follows:

1. It keeps the chromosome number constant and genetic stability in daughter cells, so the linear heredity of an organism is maintained.
2. It helps in growth and development of zygote into adult in multicellular organisms.
3. It provides new cells for repair and regeneration of lost part and healing of...

Furrowing is a type of division of cytoplasm occurs in the bacteria, fungi and animal cells. In this process, a peripheral cleavage furrow appear gradually between the two daughter nuclei.

The furrow deepens and when the edges of the furrow meet in the center of the cell, the protoplasm divides into two daughter cells.

Crossing over is a process of exchange of genetic materials between the non-sister chromatids of homologus chromosomes. It takes place in pachytene of prophase-I of meiosis.

It has following significances:

1. It produces new combination of genes and trait.
2. it increases variability of organisms.
3. Due to crossing over, different varieties of plants and animals are produced.
4. Crossing over helps in the identity of organism.
5. It is a source of raw material for evolution of life.
6. It increase immunity of...

It is a very complex and long phase. It is further divided into five successive substages.

1. Leptotene or Leptonema
2. Zygotene or Zygonema
3. Pachytene or Pachynema
4. Diplotene or Diplonema
5. Diakinesis

1. Leptotene[ GK: Leptos=thin, tene= Thread ]

• size of nucleus increases
• chromatin thread become shortened and converted into chromosomes which are thread like and single stranded.
• chromosomes passes beaded structure called chromomeres.

2. Zygotene[ GK: Zygo= yolk, tene= thread]

• pairing of homologous...

The stage of cell division in which paired homologous chromosomes get shortened and thickened is prophase I of meiosis. During this stage, the chromosomes condense and become visible as distinct structures, allowing for the homologous chromosomes to pair up and exchange genetic material through a process called crossing over. The shortening and thickening of the chromosomes during prophase I is important for proper alignment and separation of the homologous chromosomes during subsequent...

Centrioles

Germ or reproductive cells

Crossing over of genetic material takes place in Pachytene stage of meiosis.

Go (Gap 0) phase or Quiescent Phase is the resting phase in which the cell remains metabolically active but is neither dividing nor preparing to divide unless instructed to do so.

The cell division concerned with cancer is Mitosis cell division.

A kinetochore is a disc-shaped protein structure that forms on a chromatid during cell division and is associated with duplicated chromatids in eukaryotic cells.

Interkinesis is a period of rest that cells of some species enter during meiosis between meiosis I and meiosis II. Preparation of the second meiotic division occurs during interkinesis and no DNA replication occurs during Interkinesis

Mitosis is the process of cell division wherein the chromosomes replicate and get equally distributed into two daughter cells. Mitosis is called equational division because each of the two daughter cells formed, gets the same number of chromosomes as the parent.

Synaptonemal complex is formed in the zygotene stage during prophase I of meiosis I.

In animals mitosis occurs in somatic cells andin plants mitosis occurs in all except those which produce spores by meiosis.

Onion root tip.

Zygotene is the stage of prophase I where synapsis begins with a synaptonemal complex forming between homologous chromosomes whereas pachytene is the stage of prophase where crossing over of genetic material occurs between non-sister chromatids.

In the metaphase of mitosis, single chromosomes with two chromatids each, line up on the metaphase plate whereas in metaphase I of meiosis, paired chromosomes (bivalents) with four chromatids in each pair line up. In the metaphase of mitosis, each centromere possesses two kinetochores on both lateral sides, whereas in metaphase I of meiosis, the centromere possesses only one kinetochore on the side facing the pole.

Meiosis is called reduction division because the number of chromosomes in daughter cells is reduced to half that of the parent cell whereasMitosis is called equational division because the number of chromosomes and amount of DNA in daughter cells remains equal to parent cells.

The three processes during interphase are

• In the interphase, proteins are synthesized by the cells needed for mitosis.
• The cell’s DNA is replicated so that each chromosome has two molecules of DNA.
  
• More proteins are synthesized and organelles like mitochondria grow and divide.
  

1. Mitosis is responsible for the development of the zygote into an adult.
2. Equal distribution of chromosomes to each daughter cell.
3. It is responsible for the growth and development of an individual.
4. It maintains the constant number of chromosomes in all body cells of an organism.
   

Homologous chromosomes are a set of one maternal and one paternal chromosome.In meiosis homologous chromosomes pair and allows the crossing over of genetic material. This process is known as recombination.

In plant cytokinesis, cells are divided by the formation of a cell plate in the middle of the mother cell whereas, in animal cytokinesis,cells are divided by the formation of a cleavage furrow on both sides of the mother cell. similarly,cell wall formation does not occur during animal cytokinesis while cell walls form during plant cytokinesis.

Cell plate cytokinesis is a type of cell division that occurs in plant cells, where a new cell wall is formed to separate two daughter cells. This process occurs during the later stages of cell division, specifically during telophase and cytokinesis.

During the process of cell division in plant cells, the spindle fibers pull the chromosomes towards opposite poles of the cell, and a new cell wall needs to be formed to separate the two daughter cells. However, since plant cells have a cell wall...

1. Genetic material between the two growing cells is divided unequally.
2. Unequal division in amitosis causes specific irregularities in growth and metabolism.

In mitosis, the prophase is further understood by dividing it into the given sub-stages:

1.Leptotene :

In this stage the nucleus enlarges in size in the chromosome. The chromosomes appear thin, thread-like and single-stranded in this stage. They have swollen or beaded structures along their length and their ends appear converged towards one side of the nucleus called bouquet.

2.Zygotene:

In this stage, the identical chromosomes come together and form bivalent or homologous pairs. Further, ...

The process of exchange of the genetic materials between any two non-sister chromatids of homologous chromosomes is referred to as crossing over. It's significances would include :

1.Helps in the process of evolution,

2. Helps in bringing genetic variation in organisms due to the genetic recombination of genes.

3. Crossing over frequency helps in the construction of genetic maps.

Mitosis is a complex process of cell division that allows a single cell to produce two identical daughter cells. It consists of several distinct stages, each with specific events and changes occurring within the cell. Here is a simplified description of the process of mitosis:

1. Interphase: This is the phase before mitosis actually begins. The cell undergoes growth and replicates its DNA to ensure each daughter cell receives a complete set of genetic information. Interphase is divided into...

Meiosis is a complex cellular process that occurs in sexually reproducing organisms to produce haploid cells, such as gametes (sperm and eggs). It involves two rounds of cell division, known as meiosis I and meiosis II, resulting in the production of four genetically unique daughter cells.

Here is a step-by-step description of the process of meiosis:

1. Interphase: The cell undergoes a period of growth and prepares for division. During this phase, the DNA replicates, ensuring that each...

Crossing over is a genetic process that occurs during the formation of reproductive cells (gametes) in sexually reproducing organisms. It involves the exchange of genetic material between paired chromosomes, specifically between their corresponding segments known as homologous chromosomes. This exchange takes place during a stage called meiosis.

Significance of crossing over lies in the following:

1. Genetic Variation: Crossing over leads to the shuffling and recombination of genetic material...