why do cells multiply ?
Answers
Answer:
Q : What is cell ?
Ans : Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. Cells also contain the body’s hereditary material and can make copies of themselves.
Cells have many parts, each with a different function. Some of these parts, called organelles, are specialized structures that perform certain tasks within the cell.
Human cells contain the following major parts, listed in alphabetical order:
Cytoplasm :
Within cells, the cytoplasm is made up of a jelly-like fluid (called the cytosol) and other structures that surround the nucleus.
Cytoskeleton :
The cytoskeleton is a network of long fibers that make up the cell’s structural framework. The cytoskeleton has several critical functions, including determining cell shape, participating in cell division, and allowing cells to move. It also provides a track-like system that directs the movement of organelles and other substances within cells.
Endoplasmic reticulum (ER) :
This organelle helps process molecules created by the cell. The endoplasmic reticulum also transports these molecules to their specific destinations either inside or outside the cell.
Golgi apparatus :
The Golgi apparatus packages molecules processed by the endoplasmic reticulum to be transported out of the cell.
Lysosomes and peroxisomes :
These organelles are the recycling center of the cell. They digest foreign bacteria that invade the cell, rid the cell of toxic substances, and recycle worn-out cell components.
Mitochondria :
Mitochondria are complex organelles that convert energy from food into a form that the cell can use. They have their own genetic material, separate from the DNA in the nucleus, and can make copies of themselves.
Nucleus :
The nucleus serves as the cell’s command center, sending directions to the cell to grow, mature, divide, or die. It also houses DNA (deoxyribonucleic acid), the cell’s hereditary material. The nucleus is surrounded by a membrane called the nuclear envelope, which protects the DNA and separates the nucleus from the rest of the cell.
Plasma membrane :
The plasma membrane is the outer lining of the cell. It separates the cell from its environment and allows materials to enter and leave the cell.
Ribosomes :
Ribosomes are organelles that process the cell’s genetic instructions to create proteins. These organelles can float freely in the cytoplasm or be connected to the endoplasmic reticulum
Q : Why do cells multiply ?
Ans : Cell multiply by a process called mitosis. The cell cycle consists of a series of stages, including interphase, mitosis and cytokinesis, in which the cell grows and divides to produce two daughter cells. During interphase, the cells replicate their DNA, and check for enough growth and no damage in order to proceed to mitosis. During mitosis, the cell goes through different phases: prophase, metaphase, anaphase, and telophase. During prophase, DNA condenses into chromosomes, the nuclear membrane breaks down, the centrosome migrate to the poles and the centrioles in that begin to form spindles, and chromosomes appear as two chromatids held together at the centromere. Then, while undergoing metaphase, the spindle fibers attach to and align the chromosomes on the equator of the cell. Then the cell goes through anaphase in which the spindle fibers, attached to the chromosomes, shorten and pull the chromatids apart. Finally, during telophase, the cells form two new nuclei and the chromosomes begin to unwrap itself. The final stage of the cell cycle, cytokinesis, is different for plants and animals. Plant cells form a cell plate across the midline while animal cells form a furrow across the midline of the cell before the cytoplasm divides to form two daughter cells. These daughter cells are exact copy of each other.