Transcript Chapter 7 Notes - BellevilleBiology.com

Chapter 4 Notes
BIOLOGY
“The Cell”
4-1 CELLS
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Science is not static
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World is flat
Planets revolve around the Earth
Only things that we can see, exist
1665
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Robert Hooke- England: looked at a thin slice
of cork
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Where does cork come from?
He saw chambers, and called them “cells”
Why were the chambers empty?
1665…
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Anton Von Leewenhoek
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Used a single lens microscope to observe pond
water
He probably saw paramecium, euglena, and
amoebas
Paramecium
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Euglena
Amoeba
Metaboly movements of Euglena.
Cells are the basic units of life
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Cell Theory has 3 parts that are
accepted by all scientists….
1. All living things are made up of cells
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1838 Matthias Schleiden – all plants are
made of cells
1839 Theodor Schwann- all animals are
made of cells
2. New cells only come from other
cells
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1855 Rudolf Virchow said this …
3. Cells are the basic unit of structure
and function of all living things.
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Atoms are the smallest part
that can exist alone
Cells are the smallest part
that can exist alone and be
considered “alive”
Technology: define each on yr own
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Fluorescent Labels
Confocal Light microscope
Hi Resolution Video
Electron Microscope
TEM
SEM
Scanning Probe microscope
Cells: have a cell
membrane, and
have DNA at some
point in their lives
Prokaryotes/ Eukaryotes
Prokaryotes
-No nucleus
-Smaller
-Have free floating DNA
-Bacteria
-Can swim/ glide
Eukaryotes
-Have nucleus
-Larger/complex
-Specialized
-Some fd uni-cellular org
-Some fd multi cellular org
4-2 Eukaryotic Cell Structure
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Organelles; the mini organs of the
cell
In the NUCLEUS
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Nucleus- sends out instructions for
making proteins “the brain”
Nuclear envelope- separates the
nucleus from rest of cell
Nucleolus – dense region of the
nucleus where manufacturing of
proteins begin
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Chromatin- DNA + protein
Chromosomes- thickened chromatin that are
visible during cell division in nucleus
In the CYTOPLASM
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Ribosomes- where
proteins are assembled
ER- where lipid parts
needed for cell
membrane are made,
also some proteins
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Rough ER- is involved in making proteins,
ribosomes are found on its surface
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Proteins made on these ribosomes, go into the rough er
and are modified
Most proteins that are made here will be exported out of
the cell
Smooth ER- contains collections of enzymes, ready
for action
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These enzymes perform specialized tasks like
detoxification of drugs
Liver cells contain a lot of smooth ER ? Tylenol, alcohol
CYTOPLASM…
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Lysosomes: clean up crew
 Filled with enzymes, that help digest proteins,
lipids, carbs- “get the junk out of the cell”.
 Tay Sachs Disease: these don’t function properly
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Vacuoles
 Storage place for water, salts, proteins, carbs
 In plants, it is VERY LARGE, and holds water
and is under pressure – Making it possible for the
plant to support structures like leaves and flowers
 Paramecium has a contractile vacuole to pump
out excess water
CYTOPLASM…
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Golgi Apparatus: (discovered by Camillo Golgi)
modifies, sorts and packages proteins, from the ER
for storage or secretion outside the cell
 Customization, finishing touches are put on the
proteins- then they are packed and leave the
factory
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Mitochondria- “powerhouse” of the cell,
converts chemical energy in food, to a
compound the cell can actually use
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Mitochondria has its own simple circular DNA
In humans, Mitochondrial DNA is inherited from
your mom
Your heart cells many mitochondria in each cell
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Chloroplasts w/ chlorophyll
 Capture energy from sunlight, and convert it into
chemical energy
 Contain the pigment chlorophyll
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Cytoskeleton: protein filaments that help maintain
cell’s shape- also involved in movement
 Centrioles- help to organize cell division (stars) in
animals cells only
 Microtubules and filaments: help maintain cell
shape- help amoeba move
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Flagellum/ Cilia
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For movement or sweeping – respiratory tract
Sperm cells
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Cell membrane- both animals and plants
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Regulates what enters and leaves
Provides some protection and support
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Cell wall
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Present in plants, algae, fungi, and most
prokaryotes
Porous enough to allow water, oxygen and carbon
dioxide among other substances through
Fiber- and bowel movement
Strong supporting layer made of cellulose a tough
carbohydrate fiber
Why don’t cells just grow bigger?
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Adults don’t have bigger cells than kids…
they just have MORE of them
The world's tallest
man in 2007 7’9”,
Bao Xishun and his 5’6”
wife…
 most people
with acromegalic
gigantism eventually
die because of
complications from
heart problems.
 "Keeping the blood
going round such an
enormous circulation
becomes a huge strain
for the heart,"
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Why don’t cells just grow bigger?
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DNA overload….DNA would need extra
copies to handle “information demand”
Too difficult to get enough nutrients and
oxygen IN and waste products OUT
What would happen?
Calculate ratio of surface area to volume
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L * W * # of sides= surface area
L * W * H= Volume
Practice problem: if cell was a cube and its
sides were 1cm each ….figure SA?
Figure V…
What if the cell were 3cm? SA? V?
What is the ratio?
Volume increases faster than surface
area
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1*1*6=6 SA
1*1*1=1 V
Ratio 6:1
3*3*6=54 SA
 3*3*3=27 V
 Ratio 54:27 reduce… 2:1
The decrease in ratio of SA to V- makes it harder for
the cell to move needed products in and out.
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