Transcript Cells and Organelles

STRUCTURE & FUNCTION OF CELLS
LECTURE #15
MS. DAY
HONORS BIOLOGY
CELL THEORY
1.
2.
3.
All living things are
made of cells
Cells are the basic
unit of structure and
function in an
organism
•
Basic unit of life
•
Using cell division
Cells come from the
reproduction of
existing cells
CELL TYPES
 Three
Basic types of cells include:
Animal Cell
(Eukaryote)
Plant Cell
(Eukaryote)
Bacterial Cell
(Prokaryote)
**SMALLEST
ALL CELLS…
Contain 4 basic cell
structures:
Cell
Membrane
Cytoplasm
Ribosomes
DNA

**not an organelle
PROKARYOTES:
THE FIRST CELLS
 Simplest

and smallest type of cell
Ex: bacteria
 NO
nucleus
 NO/FEW organelles
 1 Single, circular chromosome (piece
of DNA)
PROKARYOTES
region
(center) contains the
DNA (NO nulceus)
 Nucleoid
by cell
membrane & cell wall
 Surrounded
ribosomes in
their cytoplasm to
make proteins
 Contain
cilia for
reproduction and
flagella for movement
 Has
eukaryotic cells EUKARYOTES
HAVE:
 All
a
Nucleus
 membrane-bound
organelles
 These
cell types
(examples) includes:
 protists
 fungi
 plants
 animals
 More
complex type
of cells
THINK: “You carry
a lot…of stuff”
TWO MAIN TYPES OF
EUKARYOTIC CELLS
Plant Cell
Animal Cell
ORGANELLES
Very
small
Perform various functions for cell
Mostly found in the cytoplasm
May or may not be membranebound
BASIC ANIMAL
CELL ORGANELLES
Nucleolus
Nucleus
Nuclear envelope
Rough
endoplasmic
reticulum
Golgi apparatus
Ribosome (attached)
Ribosome (free)
Cell Membrane
Mitochondrion
Smooth
endoplasmic
reticulum
Centrioles
BASIC PLANT CELL
ORGANELLES
CELL OR PLASMA MEMBRANE
(aka: phospholipid bilayer)
STRUCTURE
 Made of double layer (bilayer) of:
 phospholipids
and proteins
 Surrounds
outside of ALL cells
FUNCTION (JOB)
 Controls what enters or leaves the cell
Outside
of cell
Proteins
Carbohydrate
chains
Cell
membrane
Inside
of cell
(cytoplasm)
Protein
channel
Lipid bilayer
STRUCTURE
CELL WALL
• Found in:
• plants
• Made of cellulose
• Fungi
• Made of chitin
• Bacteria
• Made of different
sugar
• NOT IN ANIMAL CELLS!!!
FUNCTION (JOB)
• Protect
• Maintain shape
Cell wall
CYTOPLASM
(aka: cytosol)
STRUCTURE
• Jelly-like substance
• Mostly water
• aqueous solution
FUNCTION (JOB)
• solution for chemical
reactions to take
place in
• Holds organelles
cytoplasm
NUCLEUS
STRUCTURE
• Contains the DNA
• Bounded by a
nuclear envelope
(membrane) with pores
FUNCTION (JOB)
• Controls the normal
activities of the cell
Nuclear
pores
NUCLEOLUS
STRUCTURE
 Inside nucleus
 Cell may have 1 to 3
 Disappears when cell
divides
FUNCTION (JOB)
 Makes ribosomes
(ribosomal subunits)
MITOCHONDRION
(PLURAL = MITOCHONDRIA)
STRUCTURE
 Bean
shape
 DOUBLE membrane
 Has its own DNA
FUNCTION
 “Powerhouse” of cell
 Makes cellular
energy (ATP) using
CELLULAR
RESPIRATION
CHLOROPLASTS
STRUCTURE
 Bean shape
 DOUBLE membrane
 Has its own DNA
FUNCTION (JOB)
 Found only in autotrophs
 Carries out
photosynthesis
RIBOSOMES
STRUCTURE
Made of PROTEINS and rRNA
Think: “RIB”s are meat; meat is protein
FUNCTION (JOB)
 Make


proteins
Hooks amino acids to make proteins
Process called TRANSLATION

RIBOSOMES (CON’T)
Can be attached or
bound to
Rough ER
OR
Be free
(unattached) in the
cytoplasm
ROUGH
ENDOPLASMIC
RETICULUM (RER)
STRUCTURE
Has ribosomes on
its surface
FUNCTION (JOB)
 Helps to make
proteins for export
out of cell
SMOOTH ENDOPLASMIC
RETICULUM (SER)
22
STRUCTURE
 NO ribosomes on its
surface
 Usually attached to
RER
 Hollow tubes
FUNCTION (JOB)
 Makes lipids
 Destroys toxins (liver)
GOLGI APPARATUS
(BODIES)
STRUCTURE
 Stacks
of flat sacs (NOT
CONNECTED!)
 Looks like pancakes
with syrup drips
 “Pankcakes” NOT
connected
FUNCTION (JOB)
•
•
•
•
Modify
Sort
Package
Molecules for storage OR
transport in vesicles
Transport vesicle
“syrup bubble”
CYTOSKELETON
STRUCTURE
 Made
of proteins
 Microfilaments are
threadlike
 Microtubules are tubelike
FUNCTION (JOB)
 Help
maintain cell shape
 Help move things
around cell
CENTRIOLES
STRUCTURE
In animal cells ONLY
 Inside CENTROSOMES
 Paired structures near
nucleus (“t” shape”)
 Made of microtubules

FUNCTION (JOB)
Appear during cell division
 Help pull chromosomes
apart

CENTRIOLES & THE MITOTIC
SPINDLE
**Made of MICROTUBULES (Tubulin)
CILIA & FLAGELLA
STRUCTURE
 Made of
microtubules
Cilia
 Shorter
 more
numerous
Flagella
 Longer
 fewer (usually 1-3)
CILIA & FLAGELLA
FUNCTION (JOB) of Flagella
Moves
WHOLE cells
FUNCTION (JOB) of Cilia
Moves
fluids, gases or
small particles across cell
surface
LYSOSOMES
STRUCTURE
 They
have a low pH
(acidic!)
 Contain digestive
enzymes
FUNCTION
(JOB)
 Break
down/recycle
food, bacteria & old
cell parts
 Think=
cleaner
“Lysol”
Nucleus
1 µm
Lysosome
Lysosome contains
active hydrolytic
enzymes
Food vacuole
fuses with
lysosome
Hydrolytic
enzymes digest
food particles
Digestive
enzymes
Lysosome
Plasma membrane
Digestion
Food vacuole
(a) Phagocytosis: lysosome digesting food
VACUOLES
STRUCTURE
 Sacks for storage
 Small or absent in
animal cells
 Plant cells have a
large Central
Vacuole
 No vacuoles in
bacterial cells
STRUCTURE
 Storage for water,
food, wastes,
enzymes, etc…
NOW…LET’S PRACTICE 