Download Cells 10th class

CELLS
THE BASI C UNI T OF LI FE
-THE SMALLEST UNI T THAT CAN CARRY OUT ALL OF THE ACTI VI TI ES OF
LIFE
THE CELL THEORY
1. All living things are made of one or more cells.
2. The cell is the basic unit of structure and
organization of living things
3. All cells come from pre-existing cells
I. ALL LIVING THINGS ARE MADE FROM
CELLS
1) Unicellular: Single – celled organisms
2) Multicellular: organisms made of many cells
WHY ARE CELLS SMALL?
Cell Size Activity
II. LIMITATIONS ON CELL SIZE
• 3 Limitations on cell size:
1.
2.
3.
A cell’s parts cannot be too far from the membrane
Cell volume increases faster than its surface area
The rate of diffusion is slow, so cells can only move
materials at a slow rate
III. TYPES OF CELLS
1. Prokaryotic




Simple cells that lack an organized
nucleus and membrane bound
organelles (organelles with membranes)
All Prokaryotic organisms are single-celled
organisms
Bacteria
Oldest Forms of Life
PROKARYOTIC CELL
Flagella
Nucleoid (DNA)
Cell
Membrane
Ribosomes
Pili
Capsule
Cell Wall
III. TYPES OF CELLS
2. Eukaryotic Cells



Larger cells that contain a
membrane bound nucleus and
membrane bound organelles
Can be…. Single-Celled (unicellular)
or
multicellular (all plants and animals)
ANIMAL CELL
PLANT CELL
PLANT CELL
Chloroplast
Mitochondria
Smooth
ER
Nucleus
Cell Wall
Nucleolus
Cell
Membrane
Rough
ER
Cytoplasm
Golgi
apparatus
Vacuole
Ribosome
ANIMAL CELL
COMPARE AND CONTRAST
A PROKARYOTIC VS. EUKARYOTIC CELL
Prokaryotic Cell
Eukaryotic Cell
COMPARE AND CONTRAST
A PROKARYOTIC VS. EUKARYOTIC CELL
No Nucleus
Single-Celled Bacteria
No Membrane Bound
Organelles
Generally smaller
Simple Cells
Contain
genetic
Material
(DNA or
RNA)
Cell
Membrane
Nucleus
Single Celled or MultiCellular Organisms
Membrane Bound
Organelles
Larger and more complex
Ribosomes
Prokaryotic Cell
Eukaryotic Cell
IV. STRUCTURE AND SUPPORT
o Cell Membrane- protects and contains the
contents of the cell; important barrier allowing
some substances to enter and leave but not others
(double phosopholipid bilayer)
o Cytoplasm- the mostly fluid internal part of the cellcontains and bathes the organelles (a colloid like
gelatin)
IV. TYPICAL CELL STRUCTURES
FOUND IN CELLS
o Cytosol – the fluid part of the cytoplasm (watery)
o Cytoskeleton – Supports and gives structure and
strength to the cell, made of microtubules
STRUCTURE AND SUPPORT
CELL WALL
• The cell wall is made of cellulose. It is found in
plants in addition to the cell membrane. The cell
wall provides protection and structural support.
• Some bacteria and fungi cells also have cell walls
that are not made out of cellulose.
RIBOSOMES
(FOUND IN ALL CELLS)
• Ribosomes are small round organelles that make
proteins based on the instructions provided by the
DNA.
• Ribosomes are located in the cytosol or attached
to the endoplasmic reticulum.
Ribosomes
attached to
the ER
IV. TYPICAL EUKARYOTIC CELL
STRUCTURES
o Organelles: “little organs”- structures in the cell that
carry out various functions
 The number and kind of organelles in a cell will often
determine what kind of cell it is
 Without organelles to perform different functions,
multicellular life would not be possible
 Organelles provide compartmentalization that provides suitable
environments for chemical reactions to take place.
 Membranous organelles provide greater surface areas for
reactions to take place
ORGANELLES OF THE
ENDOMEMBRANE SYSTEM
NUCLEUS
 Nucleus – contains DNA, controls cell activity
 macronucleus: reproduction
 micronucleus: control cell functions
NUCLEOLUS
• Nucleolus
• Located inside the nucleus
• The nucleolus manufactures ribosomes
NUCLEAR ENVELOPE
• Nuclear Envelope is the membrane that surrounds
the nucleus
• The Nuclear Envelope controls what molecules are
able to enter or leave the nucleus
ORGANELLES OF THE
ENDOMEMBRANE SYSTEM
ENDOPLASMIC RETICULUM
• The ER could be compared to the cell’s “highways”
• Rough ER: This is the location where proteins are
modified and transported through the cell
• In the Smooth ER, lipids are produced and stored.
Chemical reactions required by the cell take place
here.
ORGANELLES OF THE
ENDOMEMBRANE SYSTEM
GOLGI APPARATUS
• The Golgi apparatus can be compared to a factory
and a post office
• The Golgi apparatus changes, packages, and
distrubutes products to other areas of the cells
• For example the Golgi apparatus is responsible for
packaging proteins and other macromolecules to
be “shipped” outside of the cell
MEMBRANE BOUND ORGANELLES
MITOCHONDRIA
• The Powerhouse of the Cell
• This is the location of Cellular Respiration
• In other words this is where food is converted into energy
Cell Respiration:
C6H12O6 + 6O2
Sugar + Oxygen
6CO2
+ 6H2O
Carbon Dioxide + Water + ATP (Energy)
MEMBRANE BOUND ORGANELLES
CHLOROPLASTS
• Chloroplasts are found in plants
• Chloroplasts are a class of plastids that contain
chlorophyll, a pigment used in photosynthesis. This is the
location of photosynthesis where glucose is produced
and starch may be stored.
• Photosynthesis
6CO2
+ 6H2O
Carbon Dioxide + Water
C6H12O6 + 6O2
Sugar + Oxygen
ORGANELLES
LYSOSOMES
• Lysosomes are found mainly in animal cells
• Lysosomes contain enzymes for digesting
macromolecules, old organelles, bacteria, viruses,
etc.
ORGANELLES
PEROXISOMES
• Peroxisomes are found in animal cells.
• Peroxisomes contain enzymes that create hydrogen
peroxide to break down fats, and to perform other
metabolic processes
ORGANELLES
VACUOLES
• Vacuoles are very large when found in a plant cell.
• Vacuoles are large membrane-bound vessels for
digestion and storage.
Vacuole
PLANT STRUCTURES/ ORGANELLES
LEUCOPLASTS
• Leocoplasts store starch.
PLANT STRUCTURES/ ORGANELLES
CHROMOPLASTS
• Chromoplasts are another type of plastid.
• Chromoplasts store pigments. They are the source
of color for flowers and some vegetables. The
colors serve to attract insects, birds, and animals.
COMPARE AND CONTRAST
PLANT AND ANIMAL CELL