Transcript 7.2 The Plasma Membrane

CELLS
QSR #2
 1. The shape of a cell greatly depends
on the ________ of that cell.
 2. Use nerve cells and skin cells to
explain #1.
 3. Cells differ in both shape and _____.
 4. True or false…larger cells are more
efficient at meeting their own needs than
smaller cells. EXPLAIN!!!!!!!
The Discovery of Cells
 Van Leeuwenhoek was the first scientist
to observe cells using a simple light
microscope
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It had one lens
 Compound light microscopes use a
series of lenses to magnify objects
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Can magnify up to 1500 times
The Cell Theory
 Robert Hooke used a compound light
microscope to study cork, the dead cells
of oak bark
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Box-shaped structures
Called these “cells”
Cell Theory (3 parts)
 1. All organisms are composed of one or
more cells
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Unicellular – bacteria, certain algae and
fungi
multicellular
 2. The cells are the basic unit of life
 3. Cells originate from other cells
2 types of cells
 Prokaryotes
 Eukaryotes
 Lacks internal
 Have true membrane
membrane-bound
organelles
 No nucleus
 Most are unicellular
 Bacteria/Blue Green
Algae
bound organelles
 Have nucleus
 Most are multicellular
Pros/Cons
 Prokaryotes
 Eukaryotes
 Pro: Very simple
 Con: Complex to
make-up
 Con: Non-specialized
– don’t have different
compartments that
can do different
things
build
 Pro: Very specialized
E.COLI BACTERIA-prokaryote
Eukaryotic Plant Cell
Liver Cell
Graded activity:
 On a piece of construction paper, draw
and label the parts to a prokaryotic cell.
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Must include:
 1.
color
 2. all parts labeled
 3. the functions of each part
QSR #3
 1. ________ was the first person to coin the term “cells”
after observing _____ cells under a compound light
microscope.
 2. Plant and bacterial cells are similar in that they both
contain a _______ _______.
 3. List 3 differences between prokaryotic cells and
eukaryotic cells.
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A._____________________________
B._____________________________
C._____________________________
Cell Membrane
 Also called Plasma membrane
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1. Separates the cell’s contents from the
materials outside the cell
2. Regulates what moves into and out of
the cell
3. Maintains __________________
Plasma Membrane
 Is Selectively permeable******
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Means that it will allow certain materials in
while others cannot pass
 2 Types of organic molecules make up
the cell membrane:
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Proteins
Phospholipids
 Made of 2 layers of phospholipids:
 PHOSPHOLIPID
BILAYER
Many proteins are located on the
membrane
1. Integral proteins – extend
THROUGH the membrane
2. Receptor proteins – transmit signals
across the membrane
3. Channel proteins – form pores that
can open and close
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A phospholipid:
 Has 2 fatty acid tails and a phosphate
molecule head attached to it
 Phosphate
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Head region
polar
 Fatty acid
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Tail region
Nonpolar region
QSR #4
 1. The cell membrane, also called the ______
membrane is made of____ layers of
phospholipids.
 2. Draw a phospholipid. (Use these terms to
label it: polar, nonpolar, fatty acid tails,
phosphate head)
 3. The _________ region of the membrane
loves water while the _________ region does
not.
 4. List and explain the 3 types of proteins that
are found in or along the cell membrane.
Cell Organelles
http://www.cellsalive.com/cells/cell_model.htm
Internal Structure
 A. Organelles:
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“cell organs”
Perform specific functions
1. Cytoplasm
 Jelly-like substance that fills the inside of
the cell and holds all the organelles
2. Nucleus
 Contains a cell’s DNA or chromosomes
 Only found in EUKARYOTIC cells
 Enclosed in a double membrane– a
nuclear envelope
 Is filled with pores.
Why?____________________________
3. Nucleolus (concentrated
DNA)
 Dense center inside the nucleus
 JOB: make ribosomes
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Some ribosomes are found on the
endoplasmic reticulum (ER)
Some float around in the cytoplasm
Ribosomes link together ______ ______s
to make proteins
4. Endoplasmic Reticulum
(ER)
ER: thin folds of
membranes found right outside the
nucleus
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4a.Smooth ER: contain no ribosomes (has
a smooth appearance)
4b.Rough ER: house ribosomes
 The ER makes up a highway for moving
material throughout the cell
5. Mitochondria
(POWERHOUSE)
 Transfers energy from ORGANIC MOLECULES
to ATP – which supplies the cell with energy!!!
 Bean-shaped
 Makes its own DNA (separate from nuclear
DNA)
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QSR #7
 1. List four levels of organization that combine to
form an organism.
 2. _________ is a dense area of DNA found inside
the nucleus in which ________(s) are made.
 3. Ribosomes are important since they are the sites
for ___________ synthesis.
 4. Ribosomes leave the __________ and attach to
the ____ ____, or the highway of the cell.
 5. The mitochondria contains its own ________
and turns the energy from ________ molecules into
________ that will then supply the cell with ______.
6.Golgi Apparatus
 A. Another system of flattened
membranous sacs
 B. processes, packages, and stores
proteins – can alter and adjust them if
necessary
7.Vesicles
 “little taxis”
 Carry molecules where they need to go
 After a protein is made, part of the ER
pinches off to form a vesicle surrounding
the protein
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This is how it gets to the Golgi
8.Vacuole
 Think “Vacuum”
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Bigger in plants
 sac for storage– mostly water
9. Lysosomes – one type of
vesicle
 Contain enzymes – “clean up crew”
 Defend the cell against invading bacteria
and viruses
 Break down damaged cell parts
 ****NOT found in plant cells****
 (Look at animation under awe sci
teachers)
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QSR #9
 1. What are 2 main purposes for the golgi
apparatus?
 2. ___________ are vesicles that repair
damaged cell parts and keep out invading
bacteria and viruses.
 3. Draw a diagram showing how a ribosome gets
from the nucleus to the golgi.
 4. The _______ vacuole, located inside plant
cells, is much larger because ______________.
10.Cytoskeleton -Microtubules
 Network of thin tubes and filaments that
give shape to the cell
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Ex: tent poles
 Types:
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1. cilia – short, hair-like extensions
2. flagella – long, whip-like tail used for
movement
****ONLY FOUND IN ANIMAL CELLS****
Organelles for your cell model
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Cytoplasm - icing
Nucleus – Reese cups
ER – rough and smooth – twizzlers, nerds on a rope
Ribosomes - nerds
Golgi Apparatus – air heads
Vesicles – skittles, M&Ms
Mitochondria – Mike n Ikes, hot tamales
Vacuole (Central Vacuole for plants) – air heads
Lysosomes – jelly beans
cilia and flagella- twizzlers
Cell Membrane – sour straws