Transcript Cells - The Bio Enigma

Describe this picture. What is the
basic substance required to make
this structure.?
BRICKS ACT AS BUILDING BLOCKS
TO CREAT THE BRICK BUILDING.
What are we made up of?
So what is the definition of a
cell??
They are building blocks of all
living things and they are the
basic unit of life !!!!!
What do you think the ‘building
block of a dog is ?
So what are the various
points you can think of to
describe a cell?
Cell Theory
 All living things are made up of cells.
 Cells are the smallest working units of all living things.
 They are the structural and functional unit of life.
(why?)
 All cells come from preexisting cells through cell
division.
A cell is the smallest structural and
functional unit of life.
Cell Theory
 All living things are made up of cells.
 Cells are the smallest working units of all living things.
 They are the structural and functional unit of life.
(why?)
 All cells come from preexisting cells through cell
division.
A cell is the smallest structural and
functional unit of life.
Examples of Cells
Amoeba
Plant Stem
Bacteria
Red Blood Cell
Nerve Cell
tallest trees
adult human
chicken egg
frog embryo
most eukaryotic cells
mitochondrion
most bacteria
virus
proteins
diameter of DNA
double helix
atoms
“Typical” Plant Cell
http://waynesword.palomar.edu/images/plant3.gif
“Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
Organelles
Cell Membrane
 It is the Outer membrane of an animal cell. It is
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located below the cell wall in the plant cell.
Its main function is to control the movement of
substances in and out of the cell.
It is a Double layer called lipid bi layer
Scientists say that the cell membrane is selectively
permeable, which means that only certain substances
can permeate (go through) the membrane.
It is found in both plant and animal cells
It also helps give shape to the cell
http://library.thinkquest.org/12413/structures.html
Cell membrane
Cell Wall
 Most commonly found in
plant cells & bacteria.
NOT present in animal
cells
 Surrounds the cell
membrane in a plant cell
 Most important function
is to give the cells shape
and rigidity.
 It also Supports &
protects cells.
http://library.thinkquest.org/12413/structures.html
Cytoplasm
 Jelly-like substance
 Surrounded by cell membrane
 All cell organelles are embedded in this.
 It contains the chemicals which are necessary to carry
out all the reactions that happen within a cell.
 Important chemical reactions occur in the cytoplasm
whereby some of the products are utilized by the
organelles.
Nucleus
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Easiest organelle to see under the microscope
Control center of the cell
Directs cell activities
Separated from cytoplasm by nuclear membrane
Contains genetic material – DNA
Controls the production of proteins in the cells
All the information regarding the cell and its activities are
stored here.
Nucleus
Chloroplast
 Usually found in plant cells. Also present in trace
amounts in Bacteria, fungi and algae.
 It is not present in animal cells.
 Surrounded by two membranes (inner and outer)
 Contains a green pigment called chlorophyll which
traps light energy and converts it into food through
photosynthesis.
 It contains its own DNA.
http://library.thinkquest.org/12413/structures.html
Chloroplast
Mitochondria
 Produces energy through chemical reactions –
breaking down food.
 Surrounded by two membranes (outer and inner
membrane). The inner membrane is folded several
times.
 Controls level of water and other materials in cell
 Recycles and decomposes proteins, fats, and
carbohydrates
 Contain their own DNA.
http://library.thinkquest.org/12413/structures.html
Vacuoles
 Membrane-bound sacs for storage, digestion, and
waste removal
 Vacuoles may contain large food
particles, enzymes, water, or many other
substances.
 Usually one large vacuole is present in plant cell
(takes up 95% of space)
 Animal cells have small vacuoles but they are more
in number.
http://library.thinkquest.org/12413/structures.html
Ribosomes
 Each cell contains thousands of ribosomes.
 Produced in the nucleus of a cell
 They act as factories of the cell to produce
Proteins.
 They can be found either in their free form in
the cytoplasm or attached to an organelle (The
rough Endoplasmic Reticulum.)
 It is made up of a large sub unit and a small sub
unit.
http://library.thinkquest.org/12413/structures.html
Lysosome
 Digestive organelle.
 They contain acid enzymes to break down food
particles,waste materials and cellular debris. It can also
destroy organelles that have been damaged. If the celllacks
an adequate amount of food, the lysosomes may actually
digest healthy organelles to provide the cell with energy.
 Found only animal cells
 Should the lysosome break and release its powerfulenzymes,
the entire cell can be destroyed, which is why the lysosome is
sometimes called the "suicide sac."
Endoplasmic Reticulum
 Two types – Smooth and
rough ER
 Rough ER – as they have
ribosomes attached to
their surface. Protein
synthesis occurs here.
 Smooth ER – Carbohydrate
metabolism and lipid and
steroid synthesis. No
ribosome present.
 Extends from the Nucleus