Kanav BhanotRoll no. 05

Presentation on

MITOCHONDRIA&

NUCLEUSby

CONTENTS

MITOCHONRIA

What is Mitochondria?

Structure

Functions NUCLEUS

What is Nucleus?

Structure

Functions Summary

BIBLIOGRAPHY

MITOCHONDRIAPowerhouse of the Cell

The mitochondrion (plural mitochondria)

are called the “powerhouses” of the cell.

Without them cells would be unable to

extract enough energy from the nutrients

and essentially all cellular functions

would cease.

What is mitochondria ?

• The term "mitochondria" itself was coined by

Carl Benda in 1898.

• The word mitochondrion comes from the Greek

word mitos i.e. "thread“ and chondrion i.e.

"granule".

• The mitochondrion (plural mitochondria) is a

membrane-bound organelle found in most

eukaryotic cells. Mitochondria range from 0.5 to

• These structures are sometimes described as "cellular

power plants" because they generate most of the cell's

supply of adenosine triphosphate (ATP), used as a

source of chemical energy.

• In addition to supplying cellular energy, mitochondria

are involved in other tasks such as signalling, cellular

differentiation, cell death, as well as the control of the

cell cycle and cell growth.

• Mitochondria has its own DNA which is responsible for

many enzymatic actions. Infact, it is the only organelle

other than nucleus which has its own DNA.

Structure

• The outer mitochondrial membrane

• The intermembrane space (the space

between the outer and inner membranes)

The basic structure of mitochondria is composed of two

lipid bilayer-protein membranes: an outer and an inner

membrane. The two membranes have different properties.

Because of this double-membraned organization, there are

five distinct parts to a mitochondrion. They are:

• The inner mitochondrial membrane

• The cristae space (formed by infolding of

the inner membrane)

• The matrix (space within the inner

membrane)

FUNCTIONS

Production of Energy

Mitochondria is called the “Power House” of the cell because it

produces the energy required for cellular functions. The energy

is produced during the oxidation of digested food particles like

proteins, carbohydrates and lipids by the oxidative enzymes in

cristae. During the oxidative process, water and CO2 are

produced with release of energy. The released energy is stored

in mitochondria and used later for synthesis of ATP.

Synthesis OF ATP

The components of respiratory chain in mitochondrion are

responsible for the synthesis of ATP by utilizing the energy

by oxidative phosphorylation. ATP molecules diffuse

throughout the cell from mitochondrion. Whenever energy

is needed for cellular activity the ATP molecules are

broken down.

ADDITIONAL FUNCTIONS

Additional functions of mitochondria include:

Apoptosis

Storage of calcium

Detoxification of ammonia in liver

NUCLEUSBrain of the Cell

The nucleus is the “control centre”

of the cell. It is the most important

part of the cell, exerting a

controlling influence on all cell

What is Nucleus ?

In cell biology, the nucleus (pl. nuclei; from Latin

nucleus or nucleus, meaning kernel) is a membrane-

enclosed organelle found in eukaryotic cells.

It was discovered by A.V Leeuwenhoek for the first

time. Scottish Botanist Robert Brown explained it in

more detail in 1831.

It coordinates the cell’s activities, which include

growth, intermediary metabolism, protein synthesis

and reproduction (cell division) by regulating gene

Structure

The nucleus is the largest cellular organelle in animals. In

mammalian cells, the average diameter of the nucleus is

approximately 6 micrometres (μm), which occupies about

10% of the total cell volume. Structure of Nucleus is made

up of following:

•Nuclear Membrane • Nuclear

Pores

• Chromatin •

NUCLEAR MEMBRANE

Nuclear Membrane separates the nucleus from the

cytoplasm. It is mainly made up of protein and lipids.

The nuclear envelope, otherwise known as nuclear

membrane, consists of two cellular membranes, an

inner and an outer membrane, arranged parallel to

one another.

The outer nuclear membrane is continuous with the

membrane of the rough endoplasmic reticulum (RER),

Nuclear Membrane

NUCLEAR PORES

The nuclear pores are the gateways across which

movement of RNAs and proteins takes place between

the nucleus and cytoplasm in both direction.

Each pore contains a donut-shaped, eightfold-

symmetric ring-shaped structure at a position where the

inner and outer membranes fuse.

The nucleus of a typical mammalian cell will have about

3000 to 4000 pores throughout its envelope.

Nuclear Pore

CHROMATIN

Chromatin is a thread like material made up of large

molecules of DNA.

The DNA molecule is compactly packed with the help of

specialised basic protein called histone. So chromatin

is referred as DNA Histone Complex.

The fundamental packing unit of chromatin is called

Nucleosome. Just before cell division the chromatin

NUCLEOPLASM

The nucleoplasm is a highly viscous liquid that

surrounds the chromosomes and nucleoli.

Similar to the cytoplasm of a cell.

Many substances such as nucleotides (necessary for

purposes such as the replication of DNA) and

enzymes (which direct activities that take place in the

nucleus) are dissolved in the nucleoplasm.

• The nucleolus is a discrete densely stained structure

found in the nucleus.

• A nucleolus is composed of Ribonucleic acid (RNA)

and associated proteins.

• The nucleolus produces ribosomes, which move out

of the nucleus and take positions on the rough

endoplasmic reticulum where they are critical in

protein synthesis.

NUCLEOLUS

NUCLEOLUS

NUCLEAR PORENUCLEAR MEMBRANE

FUNCTIONS

It stores the cell hereditary material, or DNA.

Site of DNA replication

Site of DNA transcription to mRNA

Ribosomal formation

Control of all cell activities that include metabolism,

protein synthesis, growth and reproduction (cell

division).

SUMMARY

From the aforesaid presentation we can conclude that

Mitochondria and Nucleus play a vital role in the normal

functioning of the cell and in case of any malfunctioning in any

of the two organelles, all the essential functioning of the cell

would cease and eventually the cell would die.

So I believe that I have been able to convey the importance of

Mitochondria & Nucleus in the normal functioning of the cell.

Bibliography

The sources that enabled me to bring out this

presentation to you all are :

TEXTBOOK OF MEDICAL PHYSIOLOGY by

GUYTON AND HALL

www.wikipedia.com