Cell Structure

Brief Account

1. Living organisms are made of basic units called CELLS.
2. The living components of a cell is called protoplasm which actually consists of the cytoplasm and the nucleus.
3. Cell membrane refers to all membranes found outside the cell which form the outer boundary of the cell, whereas, plasma membrane is the membrane at the surface which encloses the content of a cell.

Most popular Facts about cells frequently asked are about the Structure and The Function of the cell parts:

Cell membrane-Act as a selective barrier wall

-Provides and maintains the shape of the cell.
-Gives support to the cell.
-Controls movement of materials in/out of cell .
-Protective barrier between the cell and its environment.
-Maintain homeostasis.

Cytoplasm- Provides substances obtained from the external environment to the organelles.
Supports and protects cell organelles .

Nucleus- Controls all the activities in the cell.
-Contains all the genetic material of a cell in the form of chromosomes.
-Produces ribosomes and RNA (Ribonucleic acids)
-Plays an essential role in cell division.

Mitochondria- Involved in cellular respiration which releases energy stored in a form of ATP that can readily be used by cells.

Interesting Facts (Extracted):

Mitochondria are known as the powerhouses of the cell.

They are organelles that act like a digestive system that takes in nutrients, breaks them down, and creates energy for the cell.

The process of creating cell energy is known as cellular respiration.

Most of the chemical reactions involved in cellular respiration happen in the mitochondria.

A mitochondrion is shaped perfectly to maximize its efforts. Mitochondria are very small organelles. You might find cells with several thousand mitochondria.

The number depends on what the cell needs to do. If the purpose of the cell is to transmit nerve impulses, there will be fewer mitochondria than in a muscle cell that needs loads of energy.

If the cell feels it is not getting enough energy to survive, more mitochondria can be created. Sometimes they can even grow, move, and combine with other mitochondria, depending on the cell's needs.

Vacuole- plays roles in intracellular digestion and the release of cellular waste products.
-Stores sugars and amino acids in its sap.
-Support herbaceous plants by tugor pressure

Endoplasmic reticulum
-The rough RE transport proteins made by ribosomes.
-The smooth RE site of important metabolic reactions such as synthesis of lipid and membrane proteins.

Ribosome-Synthesis of proteins such as enzymes.

Interesting Facts (Extracted):

Ribosomes - Protein Construction Teams
Cells need to make proteins. Those proteins might be used as enzymes or as support for other cell functions.

When you need to make proteins, you look for ribosomes.

Ribosomes are the protein builders or the protein synthesizers of the cell. They are like construction guys who connect one amino acid at a time and build long chains.

Ribosomes are found in many places around the cell. You might find them floating in the cytoplasm (cytosol). Those floating ribosomes make proteins that will be used inside of the cell. Other ribosomes are found on the endoplasmic reticulum.

Endoplasmic reticulum with attached ribosomes is called rough. It looks bumpy under a microscope. Those attached ribosomes make proteins that will be used inside the cell and proteins made for export out of the cell.

Lysosome-Contain hydrolytic enzymes .

-Eliminate worn out or damaged organelles to enable a cell to renew itself.

Interesting Facts (Extracted):

-Lysosomes - Little Enzyme Packages
You will find organelles called lysosomes in nearly every animal-like eukaryotic cell.

Lysosomes hold enzymes that were created by the cell.

The purpose of the lysosome is to digest things. They might be used to digest food or break down the cell when it dies. What creates a lysosome? You'll have to visit the Golgi complex for that answer. A lysosome is basically a specialized vesicle that holds a variety of enzymes. The enzyme proteins are first created in the rough endoplasmic reticulum.

Those proteins are packaged in a vesicle and sent to the Golgi apparatus. The Golgi then does its final work to create the digestive enzymes and pinches off a small, very specific vesicle. That vesicle is a lysosome.

From there the lysosomes float in the cytoplasm until they are needed. Lysosomes are single-membrane organelles.

Centrioles-Strengthen cell & maintains the shape
-Moves organelles within the plant cell

Golgi apparatus-Processing, packaging and transporting centre of carbohydrates, proteins, phospholipids and glycoproteins

Chloroplasts-Site of photosynthesis

Interesting Facts (Extracted):

One of the most widely recognized and important characteristics of plants is their ability to conduct photosynthesis, in effect, to make their own food by converting light energy into chemical energy.

This process occurs in almost all plant species and is carried out in specialized organelles known as chloroplasts.

All of the green structures in plants, including stems and unripened fruit, contain chloroplasts, but the majority of photosynthesis activity in most plants occurs in the leaves. On the average, the chloroplast density on the surface of a leaf is about one-half million per square millimeter.

Interesting Links related to this chapter which you might like to follow are listed below:

http://www.biology4kids.com/files/cell_mito.html

http://www.enchantedlearning.com/subjects/animals/cell/

http://www.cellsalive.com/cells/cell_model.htm

....and of course the Diagrams.....Students must be able to identify and also able to draw and label all the structures above...

Happy Revising...