Transcript BioCellsCh7through p. 180

Chapter 7A View of the Cell:
ARE THOSE OUR CELLS?
Section 7.1 Cell:
Smallest unit that can carry out all the
activities necessary for life.
Can survive on its own or has potential
to do so
Is highly organized for metabolism
Senses and responds to environment
Has potential to reproduce
Anton Von Leeuwenhoek, the first
person to observe "animalcules"
through a microscope, didn’t at all
like what he saw.
ROBERT HOOKE— “Cells”
crude compound micriscope
Fig. 4.1, p. 50-51
The Cell Theory
Electron Microscopes
1930’s
Uses a beam of electrons
to magnify to to 500,000 X
Cell surfaces; internal
structures
CELL
DIFFERENCES
Size; Shape; Types and number of
Internal Structures
Example: muscle cells have a lot of
__________________ for ATP
production (high energy needs)
SIMILARITIES
Functionally
Two Basic Cell Types
1. Prokaryotes
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No Nucleus
No internal membrane-bound organelles
Bacteria (2 Kingdoms)
2. Eukaryotes
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Have internal membrane –bound organelles.
Other 4 kingdoms. (Animalia, Plantae, Protista,
Fungi)
7.2 The Plasma Membrane
Selectively permeable

Water and small molecules like O2, CO2 , and nonpolar
molecules --freely pass through.

Charged particles (like ions) and large molecules need
special assistance (proteins assist movement)
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-------------------------------------------Try an analogy--------------------------------------------------
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.
Plasma Membranes
Phospholipids-Polar “head” and 2
non-polar tails
Click to view
animation.
animation
The Phospholipid Bilayer
Main component of
membranes
Gives the
membrane its fluid
properties
Two layers of
phospholipids-end
to end.
Polar and Nonpolar regions
A mosiac
The Fluid Mosaic Model
A mosaic of materials
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Phospholipid bilayer
Proteins
Cholesterol
Fluid—because the phospholipids are
unsaturated.
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Some of the proteins are free to move within the
membrane too
Functions of Membrane
Components
Cholesterol—give it some stability.
Transport Proteins

Help regulate entry and
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exit of molecules and ions.
Cell Surface Markers (have sugars attached).
Attached to cell surface.

Like a cell’s ID tag.
Class Work. May work with a
partner, but each is to
complete this.
P. 174
Draw prokaryotic cell, label cell
components, color!!!
Same for the Eukaryotic cell.
How do they compare in size?
7.3 Eukaryotic Cell Structure
Cell Wall
Inflexible barrier.

Support and protection
Porous—not selective
The Nucleus
1.Contains DNA—directions for making
proteins

Chromatin-thin; non-dividing cell

Chromosomes-compact, visible when cell is
dividing
2. Nucleolus—this makes ribosomes.
RNA forms, exits nucleus through Nuclear
Pores to the Cytoplasm
Nuclear Envelope
Cell functions
Like a candy factory
Lots of Production
Need to move materials inside
Need to send Finished materials
(candy) out to sell and waste products
Movement is regulated at the perimeter
gate by security, allows controlled entry
and egress.
HOMEWORK
READ 7.3
TERMS TO KNOW
Terminology in bold fontdescribe
function
what organisms are they found in
Describe the advantage of highly folded
membranes in cells.
Homework
1. Compare and contrast prokaryote
and eukaryote cells.
2. Why are plasma membranes
describes as a “fluid mosaic”?
What is the role of cholesterol in plasma
membranes?
CELLS ARE LIKE LITTLE
CANDY FACTORIES
Structure of Cells
Cell membrane Function
Cell Size is Limited
Importance of Water in
formation of Membrane
 Polar vs. Non-Polar
 Hydrogen -Bonds
Cell Size is Limited
In most cases, a living thing grows because it
produces MORE cells
An adult simply has more cells than an
infant, not simply larger cells.
WHY more cells, not larger cells?
Remember—Membrane Function…
How fast exchange occurs depends upon the
SURFACE AREA of the cell
BUT, how quickly food & Waste are made
depends on Cell Volume
Plasma Membranes
1.Phospholipids-Polar “head” and 2
non-polar tails
Click to view
animation.
animation
Phospholipid Bilayer up close
and personal
Main component of
cell membranes
Gives the
membrane its fluid
properties
Two layers of
phospholipids
Cell Membrane Proteins
How their structure related to their
function in the membrane
2 types of CELLS
EUKARYOTE VS.
PROKARYOTE
Differences
AND
Similarities