Download Cells - 1p225RobbieSci2010

Cells
What are cells?
Cells- the building blocks of life
-Simplest units that have all the
characteristics of life
-- like a chemical factory as many
chemical reactions occur continually
inside them.
DONE BY ROBBIE , CLASS 1p2(25)
Instruments for studying parts of the cell
A light microscope
- ability to magnify objects to
- 1000x
An electron microscope
-ability to magnify object
Up to 200000x
Parts of a cell
 Cell Membrane -
found only in Plant
cells. These organelles
Nucleus are:
Nuclear Membrane  Cell Wall Endoplasmic Reticulum
 Chloroplasts Ribosomes Golgi Bodies Mitochondria Lysosomes Vacuoles –
 Cytoplasm 
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 Some organelles are
Cross-section of a Plant Cell
Cell membrane
 -cell membrane or plasma membrane
 -surrounds the cytoplasm of the cell
 Partially permeable
 -allows only some substances to cross it
 -controls substances entering or leaving
the cell.
Cytoplasm
 Part of the protoplasm between the cell
membrane and the nucleus.
 -most cell activities occur in it.
 -contains enzymes and organelles
 -organelles carry out various functions
in the cell.
Nucleus
o controls cell activities such as cell growth
and the repair of worn-out parts.
o Essential for cell division. Cells without a
nucleus, for example, the red blood cells of
a mammal, have a short lifespan and are
unable to divide.
Nuclear membrane
 -Also known as the nuclear envelope
 -It is a double-layered membrane surrounding the nucleus ,
separating the nucleoplasm from the cytoplasm
 -it is made up of two layers, each composed of a lipid bilayer.
 Acts like a shield for the nucleus.
Endoplasmic Reticulum
-Network of membranes throughout the cytoplasm of the
cell
-It is called the rough ER when ribosomes are attached and
the smooth Er when they are not attached.
Ribosomes
 Ribosomes make proteins that will be used inside the
cell.
 It can be found mostly on the ER(Endoplasmic
Reticulum)
 Ribosomes are also known as 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.
Golgi Bodies
 - The golgi body or golgi apparatus is shaped like a disc.
 -it consists of a stack of flattened spaces surrounded by
membranes.
 - the golgi body stores and modifies substances made by the
ER( Endoplasmic Reticulum) and packages these substances
in vesicles(tiny spherical spaces enclosed by a membrane) for
secretion out of the cell.
VESICLES
 Vesicles are small, membrane-bounded spheres that contain
various macromolecules. Some vesicles, , are used to
transport macromolecules from the endoplasmic reticulum
to the Golgi body, and from the Golgi body to various
destinations. Special kinds of vesicles perform other functions
as well. Lysosomes are vesicles that contain enzymes involved
in cellular digestion.
Mitochondria
 Membrane-enclosed
Organelles.
Their main function is the conversion of the potential energy of
food molecules into ATP
 an outer membrane that encloses the entire structure
• an inner membrane that encloses a fluid-filled matrix
• between the two is the intermembrane space
• the inner membrane is elaborately folded with shelflike cristae
projecting into the matrix.
Lysosomes
 -membrane-bounded organelle, found in the cytoplasm of
eukaryotic cells, which contains digestive enzymes.
 It also acts as the “garbage disposal” of the cell by breaking
down cell components that are no longer needed.
 The interior of a lysosome is strongly acidic, and its enzymes
are active at an acid pHs Lysosomes are found in all
eukaryotic cells, but are most numerous in disease-fighting
cells, such as leukocytes(white blood cells).
Vacuoles
 -fluid-filled space enclosed by a membrane. Vacuoles store
substances within the cell.
 Some animal cells have small vacuoles that contain water and
food substances, these vacuoles are usually only existing
temporarily.
 Plant cells usually have a large central vacuole which contains
the cell sap, which contains dissolved substances such as
sugars, mineral salts and amino acids.
Chloroplasts
 -oval structures found only in plant
cells
 - contain a green pigment called
chlorophyll
 -chlorophyll is essential for
photosynthesis , the process by which
plants make food.
Cell wall
 -encloses the entire plant
cell, surrounding the cell
Surface membrane.
-made up of cellulose.
Protects the cell from injury and gives the plant cell a fixed
shape.
It is fully permeable and can only be found in plant cells.
References
 www.biology-online.org
 http://dictionary.reference.com/browse/nuclear+membrane
 science.jrank.org/pages/1313/Cell-Golgi-body.html
 www.daviddarling.info/encyclopedia/L/lysosome.html
 Cell - Vesicles http://science.jrank.org/pages/1314/Cell-
Vesicles.html#ixzz0mUQ3JWc9