Cell and Cell theory

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The Cell and its
structure
• To know about cells.
• Explain the Cell functions.
• Differentiate animal cell from a plant cell.
• Discovered by Robert Hooke in 1665
.Smallest unit or the building block of all
living things plants and animal alike
• Cell reproduction is the process by which
cells divide to form new cells.
• Each time a cell divides, it makes a copy
of all of its chromosomes, which are tightly
coiled strands of DNA, the genetic material
that holds the instructions for all life, and
sends an identical copy to the new cell
that is created.
• Humans _44 chromosomes,44
autosome,2 sex choromosomes
• Ferns-1262 choromosomes
TYPES OF CELL
• Mainly cell is of two types
they are• 1) Prokaryotic cell
• 2) Eukaryotic cell
PROKARYOTIC
CELL• It is a Greek word pro=
primitive and karyon=
nucleus.
• These are small,
simple, and most
primitive.
• Probably the 1st to
came into exist on
earthy about 3.5 billion
years ago.
EUKARYOTIC
CELL• It is Greek word eu=
well and karyon=
nucleus.
• These are essentially
two enveloped system.
• They are very much
larger and complex
than prokaryotic cell.
• The 1st eukaryotic cell
may have arisen 1.4
billion years ago.
Prokaryotic
cell
PLANT
CELL
EUKARYOTIC
CELL
ANIMAL
CELL
Eukaryotic
cell
Plant
cell
Eukaryotic
cell
Animal
cell
COMPONENTS OF ANIMAL
CELL
NUCLEUS
PLASMA
MEMBRANE
CYTOPLASM
CELL STRUCTURE
LOCATION
DESCRIPTION
FUNCTION
Cell Wall
Plant, Fungi, &
Bacteria, but not
animal cells
Cell Membrane
All cells
•Outer layer
•Rigid & strong
•Made of cellulose
•Plant - inside cell
wall
•Animal - outer layer;
cholesterol
•Double layer of
phospholipids with
proteins
•Selectively permeable
•Support (grow tall)
•Protection
•allows H2O, O2, CO2 to
diffuse in & out of cell
•Support
•Protection
•Controls movement of
materials in/out of cell
•Barrier between cell and its
environment
•Maintains homeostasis
Nucleus
All cells except
prokaryotes
•Large, oval
•May contain 1 or
more nucleoli
•Holds DNA
•Controls cell activities
•Contains the hereditary material
of the cell
•Surrounds nucleus
•Double membrane
•Selectively
permeable
•Controls movement of materials
in/out of nucleus
Nuclear membrane
All cells except
prokaryotes
Cytoplasm
All cells
•Clear, thick, jellylike material
(cytosol)
•Organelles found inside cell
membrane
•Contains the cytoskeleton
fibers
•Supports and protects
cell organelles
•Network of tubes or
membranes
•Smooth w/o ribosomes
•Rough with embedded
ribosomes
•Connects to nuclear envelope
& cell membrane
•Carries materials
through cell
•Aids in making
proteins
•Provides mechanical
support
Endoplasmic
reticulum (ER)
All cells except
prokaryotes
Ribosome
All cells
•Small bodies free or
attached to ER
•Made of rRNA &
protein
•Synthesizes proteins
Mitochondrion
All cells except
prokaryotes
•Peanut shaped
•Double membrane
•Outer membrane
smooth
•Inner membrane
folded into cristae
•Breaks down sugar (glucose)
molecules to release energy
•Site of aerobic cellular respiration
•Powerhouse of the cell
Vacuole
Plant cells have a
single, large vacuole
Animal cells have
small vacuoles
•Fluid-filled sacs
•Largest organelle in
plant cells
•Store food, water, metabolic &
toxic wastes
•Store large amounts of food or
sugars in plants
•Small and round with
a single membrane
•Breaks down larger food
molecules into smaller molecules
•Digests old cell parts
Lysosome
Plant - uncommon
Animal - common
Chloroplast
Plants and
algae
•Green, oval containing chlorophyll
(green pigment)
•Double membrane with inner
membrane modified into sacs called
thylakoids
•Stacks of thylakoids called grana &
interconnected
•Gel like innermost substance called
stroma
•Uses energy from sun to
make food (glucose) for the
plant
•Process called
photosynthesis
•Release oxygen
nucleolus
All
cells except
prokaryotes
•Found inside the cell's nucleus
•May have more than one
•Disappear during cell division
•Aggregate of granules made of
Ribonucleic Acid (RNA)
*rDNA (Interphase)
•Assemble ribosomes
•Producing Ribosomes
Golgi Apparatus
All cells except
prokaryotes
•Stacks of flattened sacs
•Have
a cis & trans face
•Modify proteins made
by the cells
•Package & export
proteins
•Have a 9-2 arrangement of
microtubules
•Short, but numerous
•Movement
Cilia
Animal cells,
Protozoans
Flagellum
Bacterial cells &
Protozoans
•Have a 9-2 arrangement
of microtubules
•Long, but few in number
•Movement
Centrosomes
helps to organize spindle
Animal cells
Non membranous
fibers and distribute
mass of two rod like chromosomes during
centrioles found
mitotoc division
only in animanl cells
Cytoskeleton
All
cells
•Made of microtubules
microfilaments
•Strengthen cell & maintains
the shape
•Moves organelles within the
cell
DIFFERENCE BETWEEN PLANT AND ANIMAL
Animal cell
Plant cell
Generally smaller in size .
Generally larger in size .
Cell wall is absent.
Cell wall is present.
Lack plastid except Euglena.
Plastid are present.
Vacuoles are small and many.
Large single central sap vacuole is
present.
Plant cell have many single simpler
unit of Golgi apparatus called
dictyosomes.
Golgi apparatus is single and highly
complex
Centrosome and centrioles present
Centrosome and centrioles absent.
Anton Van Leeuwenhoek – discovered
microorganism when he was grinding
lenses and constructing simple
microscopes.
 Felix Dujardin - internal structures
 Jan Evangelista Purkinje – protoplasm
 Robert Brown – nucleus
 Matthias Schleiden - plants cells
 Theodore Schwann – animal cells

1930 – Max Knoll, Ernst Ruska – electron microscope
1959 – Rudolf Virchow – cells come from pre existing cells
THANK
YOU
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