THE CELL AND ITS
ORGANELLES
SCIENTISTS OF CELLS
Hooke  viewed cork; coined the term “cells”
 van Leeuwenhoek  first to view cells under
the microscope
 Schleiden  plants made of cells
 Schwann  animals made of cells
 Virchow  new cells only come from division of
other cells

ALL THESE SCIENTISTS LED TO THE
DEVELOPMENT OF THE CELL THEORY!
CELL THEORY
All
living things are composed of
cells
Cells are the basic units of
structure and function in living
things
New cells are produced from
existing cells
CELL CATEGORIES
Prokaryotes
 no membrane bound
organelles
 genetic material not in the
nucleus
 Cell membrane
 Small
 Eukaryotes (YOU!)
 Have organelles
 Genetic material contained
in nucleus
 Cell membrane
 Large
CATEGORIES OF CELLS
Bacteria
Prokaryotes
animal cells
plant cells
Eukaryotes
CELLS AND THE WORK OF LIFE
gas exchange: O2 in vs. CO2 out
 take in & digest food
 make energy



ATP
build molecules

proteins, carbs, fats, nucleic acids
remove wastes
 control internal conditions
 respond to external environment



What are they responding to?
build more cells

growth, repair, reproduction & development
CELL ORGANELLES
 Carry
out specialized
functions within the cell
 Lots
of different ones
found in eukaryotic
cells
 Cytoplasm
is a thick,
liquid residing between
the cell membrane
holding all living
material inside the cell
 doesn't contain the
nucleus.
CYTOSKELETON
 Acts
as skeleton
and muscle
 Provides
shape
and structure
 Helps
the cell with
movement
Microtubules
 Microfilaments

CELL WALL
 Found
in plant and bacterial
cells
 Rigid, protective and supportive
barrier
 Located outside of the cell
membrane
 Porous
 Made from fibers of carbs and
proteins


Plant Cell Walls are made from
Cellulose
Plasmodesmata: holes or
channels in the cell wall that allow
for transport/communication
1ST MAJOR FUNCTION:
CELLS NEED TO MAKE ENERGY!
 To fuel daily life & growth, the cell must…
take in food & digest it
take in oxygen (O2)
 make ATP (energy)
 remove waste


Organelles that do this work…
cell membrane
 vacuoles
 lysosomes
 mitochondria

CELL MEMBRANE
 Boundary
of the cell
 Made of a phospholipid bilayer
CELL MEMBRANE

(CTD.)
phosphate
“head”
Function
separates cell from outside
environment
 controls what enters or leaves cell



recognizes signals from other cells


O2, CO2, food, H2O, nutrients, waste
allows communication between cells
Structure

Double layer of fat


Protein molecules (50%)




phospholipid bilayer
Receptor proteins
Structural proteins
Protein channels
carb chains

ID cards
lipid “tail”
LYSOSOMES
Garbage disposal of
the cell  THEY
GET RID OF THE
CELL JUNK
 Contain digestive
enzymes that break
down wastes and
food



Food needs to be
broken down into
useable forms
Breakdown
organelles that
aren’t functioning
properly
VACUOLES
 Large
central vacuole
usually in plant cells
 Many smaller
vacuoles in animal
cells
 Storage container for
water, food,
enzymes, wastes,
pigments, etc.
FOOD &
WATER STORAGE
plant cells
food vacuole
animal cells
central vacuole
contractile
vacuole
MITOCHONDRIA


Nickname: “Powerhouse
of the cell”
Function: Convert
chemical energy stored in
food into compounds that
are usable by the cell



Cellular respiration occurs
here
Bound by a double
membrane
Has its own DNA,
ribosomes, and can make
its own protein!
MITOCHONDRIA
ARE IN BOTH CELLS!!
animal cells
plant cells
mitochondria
CHLOROPLAST
 Found
only in plant
cells
 Contains the green
pigment chlorophyll
 Site of food (glucose)
production
 Bound by a double
membrane
SECOND IMPORTANT FUNCTION
CELLS NEED TO MAKE PROTEINS!

Making proteins
 to run daily life & growth, the cell must…
read genes (DNA)
 build proteins
 structural proteins (muscle fibers, hair, skin, claws)
 enzymes (speed up chemical reactions)
 signals (hormones) & receptors


organelles that do this work
nucleus
 ribosomes
 endoplasmic reticulum (ER)
 Golgi apparatus

NUCLEUS
 Function:
Control
center of the cell
Contains DNA
 Contains instructions
for making protein

 Surrounded
by a
double membrane
 Usually only one per
cell
RIBOSOME
 Small
particles of
RNA and protein
 Function: Site of
protein synthesis
 Found attached to
rough ER or floating
free in cytoplasm
 Produced in a part of
the nucleus called the
nucleolus
ENDOPLASMIC
RETICULUM
 Nickname:
“ER”
 Connected to nuclear
membrane
 “Highway of the cell”
 Rough ER: studded
with ribosomes; it
makes proteins
 Smooth ER: no
ribosomes; functions
in detoxification; it
makes lipids!
GOLGI APPARATUS
 Function:
Stores,
modifies and
packages proteins
 Nickname: Post
office of the cell
 Molecules
transported to and
from the Golgi by
means of vesicles
THIRD IMPORTANT JOB!
CELLS NEED TO MAKE MORE CELLS!
 To
replace, repair & grow,
the cell must…
copy their DNA
 make extra organelles
 divide the new DNA & new
organelles between 2 new
“daughter” cells


Organelles that do this work
Nucleus
 Microtubules
 Centrioles

MICROTUBULES
Made
up of proteins known as
tubulins
Important in cell division
 mitotic
spindle  separates
chromosomes
CENTRIOLE
 Help
coordinate cell
division
 Found only in animal
cells

One pair in each cell
 Made
of microtubules