Transcript Organelles of the Cell - Fairless Local School District

Chapter 4
Structure and Function of the Cell
4-1 Introduction to the Cell
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Biology – The study of life
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Bio – life
Ology – study of
Cell – smallest unit of matter that can carry
on all life functions
I. Discovery of the cell
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Early 17th century (a.k.a. 1600’s) –
discovery of the microscope
1665:
ROBERT HOOKE
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The man the
discovered cells!
Looked at a slice of
cork
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Plant cells
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Saw “little boxes”
Reminded him of small
rooms that monks lived
in called cells
So that is how cells got
their name!
Cell Theory
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150 years later ….
Cell theory – 3 parts
1.
2.
3.
All living things are composed of at least one
cell
Cells are the basic unit of structure and
function in an organism
Cells come from other cells
II. Cell diversity
A. Size
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Most are microscopic few are seen by the
naked eye
Size is limited by:
Ratio of surface area to volume
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Nutrients must enter the cell
If it is too large – materials won’t enter the
cell fast enough
B. Shape
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Shape reflects function
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Examples:
Nerve cell
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Branched and long
Job: Transmit
information
Skin cells
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Flat and layers of
dead cells
Job: Protection
White Blood Cells
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Blob – move through
small openings and
eat bacteria
Job: kill bad things
C. Internal Organization
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Organelles – cell component that performs
a specific function
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Like organs of the body – “Itty bitty baby
organs”
EUKARYOTIC CELL
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Eukaryotic cell – has a nuclear membrane
and membrane- bound organelles
Just like you and me!!
All cells that are not bacteria
PROKARYOTIC CELL
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No membrane – bound organelles
No nuclear membrane
Example: bacteria cells
4-2 Parts of the eukaryotic cell
Eukaryotic cells are different
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Three main parts
1.
2.
3.
Cell membrane
Organelles
Nucleus
I. Cell Membrane
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Holds everything inside the cell
Semipermeable – (selectively permeable) –
Only allows some things through
Cell Mem. Make-up
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Made of:
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Phospholipid bilayer – fat with a phosphate
group attached
Proteins – allows certain things through
The phospholipid
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Hydrophilic end
Hydrophobic end
Latin:
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Hydro=__________
Philic=__________
Phobic=__________
The cell membrane Proteins
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Some proteins
go all the way
through the
mem.
These serve as
channels or
pores
Fluid Mosaic Model of cell mem
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What is a mosaic?
Fluid Mosaic Model of cell mem
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For many years scientists thought that
proteins were static
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(stuck in 1 place)
The phospholipid bilayer behaves more
like a fluid than a solid
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Proteins can move
Cell membrane is always changing
II. Organelles of eukaryotic cells
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Organelles – Parts that make-up the cell
1. Cytoplasm
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Area between cell mem. and nucleus
Also called cytosol
2. Mitochondria (MIGHTY)
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Powerhouse of the cell
(Makes energy)
Makes ATP (adenosine
triphosphate) -molecule
that gives us energy
Double membrane with
series of folds (Cristae)
Highly active cells= lots
of mitochondria
Has own DNA
Comes from your mama
Mitochondria
3. Ribosome
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Help make proteins
Most numerous
NOT membrane bound (in bth eukaryotic
and prokaryotic cells)
Some are free others are attached to the
endoplasmic reticulum
Ribosome
4. Endoplasmic Reticulum
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System of tubules and sacs
Function= path for molecules
Two types:
1.
2.
Rough E.R. – has ribosomes
Smooth E.R.- no ribosomes
Smooth Endoplasmic Reticulum
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Forms channels
within the cell
Breaks down and
make lipids
Helps detoxify
chemicals
Rough Endoplasmic Reticulum
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Rough b/c of
ribosomes on the
outside
Ribosomes help make
proteins
RER connects to the
nucleus and helps
make proteins
E.R.
5. Golgi Body (apparatus)
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Processing,
packaging, and
shipping proteins
Stacked membranes
Vesicles (membrane
bound bags) carry
materials.
Golgi
Protein from rough E.R to golgi
6. Lysosome
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Latin: Lys – to break or split
Sac filled with digestive enzymes
Digests anything bad – like the garbage
disposal of the cell.
Suicide sac-can kill a cell
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Human hand begins as a solid and lysosome
kills cells to make spaces btwn fingers
Lysosome
7. Cytoskeleton
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Provides support
Move organelles within the cytoplasm
Two types:
1.
2.
Microfilaments – play a role in cellular
movement
Microtubules – form spindle fibers (attach to
centrioles and chromosome during cellular
division
Microtubules/Spindle fibers
8. Cilia
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Short hair like extensions that help with
movement (made of microtubules)
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Single-celled organisms use it to move
Multi-cellular organisms use it to clean
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Ex: Respiratory system
Paramecium w/ cilia
9. Flagella
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One up to a few long whip – like
extensions
Whip around to move a cell
Flagellum example:
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A SPERM CELL!!!
Cilia and Flagella
III. Nucleus
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Filled with
Nucleoplasm
Three main parts
1.
Surrounded by semi permeable membrane
(Nuclear membrane/ envelope)
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2.
Nucleolus
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3.
Double mem. That surrounds the nucleus
Has pores
Helps make ribosomes
DNA
DNA (Deoxyribonucleic acid)
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Two forms of DNA
1.
2.
Chromosome )( - DNA is condensed around
proteins – ONLY during cellular
reproduction
Chromatin – DNA is all spread out like a
plate of spaghetti
Nucleus
The Cell
IV. Plant Cell
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Plant cells have all the other organelles +
three others
1. Cell Wall
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Outside the cell membrane
Helps support and protect
2. Vacuole
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Storage for water and
food
Much larger in plant
cells
May not exist in some
animal cells
3. Chloroplasts
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Contain chlorophyll
Chlorophyll is the
pigment that allows
plants to make food