The Cell
The building blocks of life
Learning Goals

I can describe the cell theory.
 I can differentiate between a prokaryotic and
eukaryotic cell.
 I can describe the similarities and differences
between a plant and animal cell.
 I can describe the structure and function of
the organelles within a cell.
 I can explain how cells move substances into
and out of the cell.
The Cell
 Every
living thing is made up of cells.
 The human body is made of 10 trillion
cells.
 Cells are factories for producing energy,
proteins, other molecules, and other
cells.
History of the Cell
 Throughout
history, people have tried to
described what makes up living things.
 In 1665, Robert Hooke describe the first
cells in a slice of cork.
 The first person to describe living cells
was Dutch lens maker, Antonie van
Leeuenhoek, in 1675.
The Cell Theory
 The
 All
cell theory states:
living things are made of cells.
 The cell is the smallest living thing
capable of carrying out life functions.
 All cells come from preexisting cells.
The Cell Theory
 Throughout
the next century, the work
of three scientists, Dutch botanist
Matthias Schleiden (1838), German
zoologist Theodor Schwaan (1839), and
German doctor Rudolph Virch (1855)
helped develop the Cell Theory.
How big is a cell?
 Cells
range in size from the enormous
eggs of the ostrich to the smallest
bacteria that are around 0.1μm.
 Most Prokaryotic cells range from 110μm.
 Most Eukaryotic cells range in size from
10-100μm.
Prokaryotic Cell
 No
Nucleus
 DNA mass in the center of the cell.
 Contains cytoplasm, ribosomes, and a
cell membrane
 Much smaller than eukaryotic cells
Eukaryotic Cell
 Eukaryotic
cells contain membrane
bound organelles.
 Parts
that carry out specific functions.
 Mini organs
 Organelles
 Nucleus,
include:
ribosomes, mitochondria, Golgi
apparatus, Endoplasmic Reticulum,
Vacuoles
Plant Cell vs. Animal Cell
 Plant Cell
 Chloroplasts
 A large central
vacuole
 Cell wall
 Animal Cell
 No chloroplasts
 No cell wall
 No central
vacuole
 Centromere
The Cell Membrane
 The
plasma membrane of both animal
and plant cells are essentially the same.
 A lipid bi-layer
 Two
layers of phospholipids
Charged at one end
 Uncharged on the other.

The Fluid Mosaic Model
 The
membrane is not a rigid, static
sheet.
 The lipids within the membrane move
and flow much like a liquid.
 The components of the membrane
determines the viscosity, or how well it
flows.
Within the Membrane
 Within
the lipid bi-layer, proteins and
other molecules are imbedded.
 This allows for sites of transport across
the membrane.
 Transport
of molecules that can not move
via diffusion.

A Selectively Permeable
Membrane
 Due
to the polar and non polar ends of
the lipids, only certain materials are
allowed to pass.
 This makes the cell membrane
selectively permeable.
 Only
certain molecules are allowed to
pass.
 Size and charge are major determiners.
Osmosis and Diffusion
 Because
the cell membrane is
selectively permeable, only certain
molecules are allowed to cross.
 The movement of any material is called
diffusion.
 Materials
move from areas of high
concentration to areas of lower
concentration.
Osmosis
 The
movement of water across that
selectively permeable membrane is
known as osmosis.
 Water
also moves from an area of high
concentration to low concentration.
Other types of Transport
 Facilitated
Diffusion-
 The
movement of molecules across the
membrane with the help of a protein
 Active
 The
Transport
movement of substances across a
membrane that requires energy to happen.
 Occurs against the concentration gradient.
Other Types of Transport
 Exocytosis Release
of molecules out of the cell
 Happens by the fusion of a vesicle with the
cell membrane.
 Endocytosis
 Pulling
molecules into the cell, by making a
vesicle.
Endocytosis
 Pinocytosis
 The
taking in of liquids by a cell
 Cell drinking
 Phagocytosis
 The
taking in of solids
 Cell eating
Cell Anatomy
Inside the Cell Membrane
Parts of the Cell

Cell membrane, membrane bound
organelles, and cytoplasm


Cytoplasm- the space between the cell membrane
and the nucleus
Membrane bound organelle are surrounded
by membranes similar to the cell membrane.




Nucleus
Mitochondria
Chloroplasts
Vacuole
-- Endoplasmic Reticulum
-- Golgi Apparatus
-- Lysosome
-- Ribosomes (no membrane)
The Nucleus
 The
brain of the cell
 The nucleus contains most of the
genetic material (DNA) for the cell.
 Parts of the Nucleus:
 Nuclear
Envelope
 Nucleolus
 Chromatin/Chromosomes
Parts of the Nucleus
 Nuclear
Envelope
 Double
membrane that separates the
nucleus from the rest of the cell.
 Covered with pores that allow the cell to
regulate the traffic in and out of the
nucleus.
Parts of the Nucleus
 Nucleolus
 Structure
located inside of the nucleus
 Where the parts of ribosomes are made
and assembled.
 The number and size of the nucleolus
depends on the cell.
Parts of the Nucleus
 Chromatin
 Place
between the nuclear envelope and
the nucleolus
 Contains the genetic material for the cell

Looks like a mass
 Genetic
Material is in the form of
Chromosomes as the cell gets ready for
division.
The Mighty Mitochondria

The cell power plant
 Bean shaped organelle made of two
membranes.




The first membrane covers the outside of the
organelle.
The second membrane is folded into a network
called cristae
Between the cristae, there is a mass of material
called the matrix.
Within the Cristae and the Matrix of the
mitochondria, the cell performs cellular
respiration

Breaking down of glucose into CO2 , water, and
energy in the form of ATP
Chloroplasts

Sugar Factory in Plant Cells
 Two membrane system with a set of flattened
sacs that contain the green pigment,
Chlorophyll, and other things necessary for
photosynthesis.
 Within the chloroplasts, plant cells make
sugar (glucose) from CO2 and energy from
the sun, a process called photosynthesis.
Chloroplasts
 Within
the inner membrane of the
chloroplasts are there are flatted sacs
called thylakoids.
 Stacks of thylakoids are called granula.
 Between the granula, there is a network
of membranes called the stroma
 Different steps of photosynthesis takes
place in each of the portions of the
chloroplasts.
Other Plastids
 Plant
cells contain a set of organelles
called plastids.
 Included in this group are the
chloroplasts.
 Usually contain a pigment or other
substance
 Gives
flowers and fruit red color
 Some plastids in roots hold starch
Endoplasmic Reticulum

Manufacturing/processing center of the cell.
 The complex network of membranes
produces/processes lipids, hormones, and
many other products of the cell.

Depends upon the functions of the cell.

It also acts as a filter to clean drugs and other
chemicals within the cell.
 Two Types:


Smooth ER
Rough ER-covered in Ribosomes
Ribosomes

Protein Makers of the Cell
 Reads the code from the DNA to polymerize
the amino acids to make proteins.
 No membrane- Ribosomes are essentially
large molecules


Made of two pieces
Some are free - loose in the cytoplasm
 Some are bound – attached to the rough ER
Golgi Apparatus
 The
packaging, warehousing, sorting,
and shipping center for the cell
 Substances enter on one side of the
Golgi, get packaged or finished, then
are sent away in a vesicle.
A
little package that transports the
substance to a different organelle, or out of
the cell.
Lysosomes


Cell Stomach
Only a single membrane, contains digestive
enzymes
 Location for digestion of food particles
 After phagocytosis, a lysosome will attach to
the vesicle, dump digestive enzymes, and
catabolizes the material.
 Also digests damaged organelles, acts as
clean up crew.

Takes in damaged organelles and catabolizes
them into their basic parts
Vacuoles
 Storage
system for cells.
 Varying types have different functions.
 Food Vacuoles – contain food from
phagocytosis
 Contractile Vacuole – regulate water in
certain protists
 Central Vacuole – large vacuole in plant
cells.
Central Vacuole
 Have
many functions in plant cells
 Stores
organic and inorganic compounds
 Stores by-products from cell metabolism
that might be dangerous to the cell
 Some hold pigments that color cells
 Some contain poisons against predators
 Made from the smaller vesicles made by
the ER and the Golgi
 Important in the growth of the plant cells
The Cytoskeleton
 The
cell’s support system
 Also allows for cell movement
 Three types of fibers:
– Largest
 Microfilaments (actin filaments) – smallest
 Intermediate filaments – middle sized.
 Microtubules
The Cytoskeleton

Microtubules






Hollow rods of protein.
Shape and support cell
Help certain organelles move around the cell.
Also involved in the separation of chromosomes
during division.
Grow out of the centrosomes
Centrioles



Set of microtubules arranged in a ring.
Only in animal cell
Help organize microtubules during division
Cell Mobility
 Cilia
and Flagella
 Specialized
arrangements of microtubules
that allow for movement-generally the
same arrangement for all cells
 A core of microtubules covered in an
extension of the cell membrane
Cell Mobility

Cilia

short hair like structures, generally in large
numbers on the outside of the cell



Allow cell to move using a beating motion.
Also allows for the movement of substances
across the cell


Around 2-20 μm long
Cleans materials out of the trachea in humans
Flagella

Whip-like structure, much longer than cilia


10-200μm long
Movement is much like the movement of a snake
through water.
Other Types of Cell Mobility
 Pseudopodia
 False
feet
 Cell crawls by extending cytoplasm out and
pulling itself along
 Cytoplasmic
 Way
Streaming
to flow cytoplasm around cell
 Occurs mostly in plant cells
The Cell Wall
 Not
in animal cells
 Thicker than the cell membrane
 Around
0.1 μm to several μm thick
 Serve
as a structural support for the
plant as a whole
 Made of carbohydrate- cellulose
 With

other polysaccharides and proteins
Act to reinforce – like steel in concrete