DAVE ARTHUR ROBLEDO
Biology Instructor
Cell Biology
Cell biology also known
as “cytology” is the study of
cell structure and function,
and it revolves around the
concept that the cell is the
fundamental unit of life.
History of Cell Biology
• The term “cell” was first
introduced by an English
scientist, Robert Hooke, in 1667.
• He used one of the earliest
microscopes to examine thin
slices of cork from the bark of a
tree.
History of Cell Biology
• Hooke saw closely-packed little
boxes with thick walls – “cells” just
like the cells in honeycombs or
prison.
• In fact, Hooke only saw the walls of
dead plant cell.
History of Cell Biology
Microscope Cork cells
Cells
Cells are the building block of life. They are the
simplest units that exhibit the characteristics of life.
Cell Theory
Cell Theory is one of the basic principles of biology.
3 Principles of Cell Theory
1. Cell is the basic unit of structure and
organization in organisms.
2. All living organisms are composed of cells.
3. Cell arise from pre-existing cells.
Cell Theory
“Cell is the basic unit of structure and organization
in organisms.”
2 Types of Organisms
Robert Hooke Unicellular Multicellular
Cell Theory
“All living organisms are composed of cells.”
Theodor Schwann Matthias Schleiden
All animals are made All plants are made of
up of cells. cells.
Cell Theory
“Cell arise from pre-existing cells.”
Rudolf Virchow
Parts of the Cell
• Cell is the basic unit of life.
• Protoplasm – “proto” means first, “plasm”
means form. The protoplasm of a cell is made
up of three parts:
1. Cell membrane
2. Nucleus
3. Cytoplasm
Cell Membrane
• Cell membrance is a.k.a. plasma membrane.
• It surrounds the cytoplasm of the cell.
• It is semi-permeable: allows only some
substances to pass through it.
• Hence, it controls substances entering or
leaving cell.
Cell Membrane
Cell membrane = “gatekeeper of the cell”
Cell Membrane
According to
Singer & Nicolson,
Cell membrane is
described as
“fluid mosaic”.
Nucleus
• Nucleus is a.k.a the “control center of the cell.”
• It controls cell activities such as cell growth and
the repair of worn-out parts and cell division.
• It contains DNA.
• It is surrounded by
double-layer membrane.
Parts of the Nucleus
Nuclear envelope
It is a double-layer
membrane which
separates the contents
of the nucleus from the
rest of the cytoplasm.
Parts of the Nucleus
Nucleoplasm
It is the dense material
within the nucleus.
Parts of the Nucleus
Nucleolus
It is the largest
structure in the nucleus
of eukaryotic cells. It is
best known as the site
of ribosome biogenesis
for protein synthesis.
Parts of the Nucleus
Chromatin
It is a complex of DNA
and proteins called
“histones” that forms
chromosomes within
the nucleus of
eukaryotic cells.
Parts of the Nucleus
Nuclear pore
It is the channel in the
nuclear envelope that
regulates the transport
of molecules between
the nucleus and the
cytoplasm.
Cytoplasm
• Cytoplasm is the part of the
protoplasm between the cell
surface membrane and the
nucleus.
• Cytoplasm is the combination
of jelly-like substance called
“cytosol” and the organelles.
Organelles
1. Cell wall
• These parts are 2. Endoplasmic Reticulum
embedded within 3. Mitochondrion
the cytoplasm. 4. Vacuole
5. Lysosomes
• Organelles are often
6. Peroxisomes
enclosed by their 7. Chloroplast
own membrane. 8. Golgi apparatus
9. Centrioles
Cell Wall
• Cell wall is a rigid organelle. It provides support,
protection and shape of the cell.
• It is present ONLY in:
1. Plants
2. Fungi
3. Bacteria
Cell Wall
Structure
Type Plant Fungi Bacteria
Component Cellulose Chitin Peptidoglycan
Endoplasmic Reticulum (ER)
• ER is also known as “highway
system” of the cell.
• It is a network of
membranous tubules within
the cytoplasm, continuous
with the nuclear membrane.
Endoplasmic Reticulum (ER)
Rough ER Nucleus
Rough ER is
called rough because it
has ribosomes attached
to its surface.
Funtion:
Protein Synthesis
Endoplasmic Reticulum (ER)
Smooth ER Nucleus
Smooth ER is not
associated with
ribosomes.
Funtion:
Lipid Synthesis
Mitochondrion
• Mitochondrion is a.ka. “powerhouse” of the cell.
• Mitochondria are sausage-shape organelles that
is considered the power generators of the cell,
converting oxygen and nutrients into adenosine
triphosphate (ATP).
• ATP is the energy of the cell.
Parts of Mitochondrion
Cristae Outer Membrane
It is the infolding of Inner Membrane
the inner membrane.
Matrix
It is the liquid inside the
mitochondrion.
Vacuoles
• Vacuole is a.ka. “storage tank” of the cell.
• It is a space within a cell that is empty of
cytoplasm, lined with a membrane, and filled
with fluid.
• Function: storage of food, water and wastes.
Vacuoles
Animal Cell Plant Cell
Vacuole
Lysosomes
• Lysosome is a.ka. “suicide bags” of the cell.
• An organelle in the cytoplasm of the cells
containing hydrolytic enzymes enclosed in a
membrane.
• Function:
1. used to digest food and protection.
2. break down the cell when it dies.
Lysosomes
Animal Cell Plant Cell
Lysosome
Lysosomes for Protection
Lysosome
Bacterium
Lysosomes for Cell Suicide
Apoptosis is the death of
cells that occurs as a
normal and controlled
part of an organism's
growth or development.
Peroxisomes
• It is small organelle that is present in the
cytoplasm of many cell that contains enzymes.
• Functions:
1. absorb nutrients that the cell has acquired.
2. play a part in the way organisms digest
alcohol (ethanol).
Peroxisomes
Chloroplast
• Chloroplasts are organelles found in plant cells
and eukaryotic algae that conduct
photosynthesis.
• Chloroplasts absorb sunlight and use it in
conjunction with water and carbon dioxide gas
to produce food for the plant.
Parts of Chloroplast
Inner Membrane Outer Membrane
Granum
Stroma Thylakoid
Golgi Apparatus
• It is the “post office” of the cell.
• It is a complex of vesicles and
folded membranes within the
cytoplasm of most cells,.
• Function:
1. waste secretion
2. intracellular transport.
Golgi Apparatus
Centrioles
• These are minute
cylindrical organelles near
the nucleus in animal
cells, occurring in pairs
and involved in the
development of spindle
fibers in cell division.
Centrioles in Sperm Cell
Sperm Cell
Ribosome
• Ribosome is NOT considered as an organelle
because it lacks membrane covering.
• It is a complex molecular machine, found
within all living cells, that serves as the site
of protein synthesis.
Ribosome
• Ribosomes can be found in ALL types of cells. It
can be located in:
1. Cytoplasm
2. Rough ER
Cytoskeleton
• Cytoskeleton is also known as “framework” of
the cell.
• These structures give
the cell shape and help
organize the cell's parts.
• It is also present in ALL
types of cell. Cytoskeleton
3 Components of Cytoskeleton
Microfilament
Microtubule
Intermediate
Filament
How do cells move around?
White blood cell Actual footage of
chasing a bacterium. swimming sperm cells.
How do cells move around?
Movements of Amoeba
paramecium
Cell Motility
• Cell Motility is required for many important
physiological processes during cell development,
such as cell migration and cell regeneration.
3 Locomotive Structures of Cell
1. Cilia
2. Flagella
3. Pseudopodia
Cilia
• Cilia is hair-like filament
that is numerous on tissue
cells of most animals and
provides the means for
locomotion of protozoans
and other cells.
Cilia
Flagella
• Flagellum is a whip-like structure that allows
a cell to move.
Euglena Sperm cells
4 Types of Flagellar Arrangement
Peritrichous Monotrichous Amphitrichous Lopotrichous
Pseudopodia
• “Pseudo” means false and “Podia” means “foot”.
• It is cytoplasm-filled
projection of an eukaryotic
cell membrane or a
unicellular protist.
• Function:
Movement and Ingestion Amoeba
2 Classifications of Cells
Eukaryotic Prokaryotic
“Eu” means true and “Pro” means before and
“karyo” means nucleus. “karyo” means nucleus.
This is a type of cell This is a type of cell
with true nucleus. without nucleus.
Difference of Eukaryotes and Prokaryotes
Eukaryotic Prokaryotic
SIZE: SIZE:
Larger than 10 Smaller than 10
micrometres. micrometres.
Difference of Eukaryotes and Prokaryotes
Eukaryotic Prokaryotic
DNA: DNA:
DNA is linear and DNA in a ring form
enclosed within a and free in cytoplasm.
nucleus.
Difference of Eukaryotes and Prokaryotes
Eukaryotic Prokaryotic
Organelles: Organelles:
With organelles Without organelles
Difference of Eukaryotes and Prokaryotes
Eukaryotic Prokaryotic
Cell wall: Cell wall:
Cell wall is made up of Cell wall is made up
cellulose or chitin. of peptidoglycan.
Similarities of Eukaryotes and Prokaryotes
Eukaryotic Prokaryotic
They both have:
Ribosomes
Cell membrane
DNA
Cytoskeleton
Cell wall (different composition)
Comparative Cell Biology
Animal Cell Plant Cell
Similarities of Animal and Plant Cells
Animal Plant
They are both eukaryotic cell.
They both have:
Cell membrane Golgi apparatus Cytoplasm
Nucleus Mitochondrion Rough ER
DNA Lysosomes Smooth ER
Cytoskeleton Ribosomes Peroxisomes
Difference of Animal and Plant Cells
Animal Plant
Size: Size:
Smaller Larger
Difference of Animal and Plant Cells
Animal Plant
Shape: Shape:
Do not have definite Have a fixed shape.
shape.
Difference of Animal and Plant Cells
Animal Plant
Cell wall: Cell wall:
Absent Present
Difference of Animal and Plant Cells
Animal Plant
Vacuole: Vacuole:
Usually absent. If Have a large central
present, vacuoles are vacuole.
small.
Difference of Animal and Plant Cells
Animal Plant
Chloroplast: Chloroplast:
Absent Present in green
plants.
Difference of Animal and Plant Cells
Animal Plant
Centrioles: Centrioles:
Present Absent
Difference of Animal and Plant Cells
Animal Plant
Food storage: Food storage:
Glycogen Starch
Review of Animal Cell
Cell membrane
Mitochondrion
Lysosomes
Golgi Apparatus
Vesicles
Review of Animal Cell
Vacuole
Centrioles
Nucleus
Rough ER
Cytoplasm
Review of Animal Cell
Smooth ER
Nuclear envelope
Nuclear pore
Nucleolus
Nucleoplasm
Review of Plant Cell
Cell Wall
Cell membrane
Chloroplast
Vacuole
Lysosome
Review of Plant Cell
Mitochondrion
Cytoplasm
Rough ER
Smooth ER
Golgi Apparatus
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