Cell Metabolism and Mitosis
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Cellular Respiration
Total cell metabolism
Mitosis
Review of cells
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Cell metabolism
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Catabolic pathways: break down larger molecules in
to smaller ones (starch into sugar, proteins into amino
acids, for example) releasing energy, most of which is
lost as heat, but some can be stored as ATP
Anabolic pathways: Build up larger molecules from
smaller component parts (for example, assembling
proteins from amino acids, assembling lipid
membranes from fatty acids). These reactions use
energy, usually provided by breaking high energy
phosphate bonds of ATP
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
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What is cellular respiration?
Occurs in the
mitochondria
Production of ATP
in a cell
Usually glucose is
main “energy”
molecule enters
cellular respiration
Includes:
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–
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Glycolysis
Citric acid cycle
Electron transport
chain
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Oxygen and
"cellular respiration”
• Cells use carbohydrates
to make ATP, which
stores high energy
bonds for anabolic
pathways.
• Oxygen allows for
complete "burning" or
catabolic breakdown of
sugars in Krebs Cycle
• But some ATP can be
obtained in anaerobic,
or pathways that are
free of oxygen
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Glycolysis
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Kreb’s cycle
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Electron transport chain
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
What other molecules besides glucose
can be used in cellular respiration?
• Other carbohydrates
• Proteins
• Lipids
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
"Raw material" for
anabolic or synthetic
pathways
• amino acids
• fatty acids
• nucleotides
• sugars
Some cells can make
most of these from
crude and even
inorganic
material. Some cells
need to obtain these
from environment
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
How can a cell make ATP without oxygen?
• Fermentation
– Occurs in the cytoplasm
– Does not require oxygen
– Involves glycolysis
– Makes 2 ATP and lactate in human cells
– Is important in humans for a burst of energy
for a short time
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Fermentation is oxygen-free
respiration where organic
molecules are ultimate
electron acceptor. Many
groups of bacteria are
fermenters.
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
All of cell metabolism
• Cell metabolism is much more than simply making
ATP, or cellular respiration, which is just how the
cell has an energy supply.
• What does the cell do with that energy?
• Get ready for what you are about to see…
• The cell runs all the reactions that make it alive—
see the first part of this presentation: grow,
reproduce, develop, move, maintain internal
homeostasis, respond to stimuli.
• This involves a LOT of chemical reactions.
• Here it is: most of the reactions involved in
keeping the simplest of cells—an E. coli bacteria—
alive!
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Ecocyc—database of complete E. coli metabolism
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
What’s it all mean?
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Every little box represents a stage in a particular
chemical reaction. The sum of those reactions is the
total cell metabolism—what makes the cell alive!
You’ll actually visit the ecocyc database under the
web links for this section as the last thing you do
Remember three things:
1. every one of these reactions is catalyzed by a protein
2. The amino acid sequence for those proteins are coded for in the
DNA
3. The world’s biggest super-computers are trying to figure out how,
based on their unique amino acid sequence, all the different cellular
proteins take on the particular shape they have, and control the
particular reaction they catalyze. (You’ll also visit the Blue Gene
IBM super-computer website in the web links for this section.)
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Blue Gene
http://www.research.ibm.com/journal/sj/402/allen.html
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
GENETICS
(the quick view—much more later)
• Cells divide and pass on
instructions coded in DNA of
chromosomes
• Each chromosome is a huge DNA
molecule with coded information
– DNA replicates to pass on information
– DNA is transcribed to make proteins
that run cell metabolism
• Cancer—example of what happens
when genetic control goes awry
• Normal inheritance and meiosis
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Mitosis—cell division
• Why do cells divide?
– Growth—so tissues/structures can become
larger
– Replacement—many tissues are constantly
being replaced because they get worn out or
used up. E.g. blood, skin, lining of gut, sperm
– Repair—when tissues get damaged due to
injury
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Mitosis—what happens (overview)
• DNA/chrosomes replicate
(make exact copies
• Copies line up at center
of cell
• Copies pulled to opposite
ends of cells by
centromeres/spindles
• Cell membrane pinches
off and splits cell into two
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Mitosis—details/stages
1. Prophase
3. Anaphase
2. Metaphase
4. Telophase
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
1. Mitosis: Prophase
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Chromosomes condense and
become visible
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Nuclear envelope fragments
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Nucleolus disappears
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Centrosomes move to
opposite poles
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Spindle fibers appear and
attach to the centromere
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
2. Mitosis: Metaphase
• Chromosomes line
up at the middle of
the cell (equator)
• Fully formed spindle
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
3. Mitosis: Anaphase
• Sister chromatids
separate at the
centromeres and
move towards the
poles
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
4. Mitosis:Telophase and cytokinesis
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Chromosomes arrive at
the poles
Chromosomes become
indistinct chromatin
again
Nucleoli reappear
Spindle disappears
Nuclear envelope
reassembles
Two daughter cells are
formed by a ring of actin
filaments (cleavage
furrow)
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Mitosis—constant, fast,
keeps body functioning
• Remember, mitosis produces two identical
daughter cells
• Mitosis is constantly happening in your body
to allow for growth, replacement and repair
• While you read this slide, millions of new
cells were produced by mitosis in the tissues
of your body!
• Don’t forget cellular scale and intelligence—
it’s a whole planet happening at the submicroscopic level
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Review of class so far
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
The Carbon-chain Molecules of Life
MOLECULE
MADE OF
FUNCTION
Carbohydrates
Simple Sugars
Energy
Proteins
Amino Acids
Fats
Fatty Acids
DNA/RNA
Nucleotides
(bases)
Catalyze
reactions
Cell
membranes
Information
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Cells are fundamental unit of life
• Cells are the basic
and fundamental
unit of life
• The first life was
cellular life
• The Molecules of
Life are what cells
and all their
internal parts are
made up of
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
WHAT CAN EUKARYOTIC CELLS
DO?
WHAT STRUCTURES ARE
INVOLVED?
Separate inside of cell from external
environment and control what
substances pass across membrane
Cell Membrane
Produce proteins/enzymes that
catalyze chemical reactions or control
movement across membrane
Nucleus (DNA), Ribosomes on rough
endoplasmic reticulum
Break down sugars to form energy
which is stored in phosphate bonds of
ATP
Mitochondria
Organize distribution of Molecules of
Life (macromolecules) and ions
throughout cell
Internal membrane system and
“cytoskeleton” (ER, lysosomes,
vessicles, microtubules)
Move
Flagella, cilia, pseudopods
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
A cell membrane or plasma membrane separates cell
from outside world—creates ability to regulate internal
environment (homeostasis)
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Protein synthesis
• Remember that proteins control cell
metabolism—how and where are they
made, or synthesized in the cell?
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Cell metabolism
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
What do mitochondria do and
what do they look like?
• A highly folded
organelle in
eukaryotic cells
• Produces energy in
the form of ATP
• They are thought to
be derived from an
engulfed prokaryotic
cell
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
•
•
•
•
What is cellular respiration?
Occurs in the
mitochondria
Production of ATP
in a cell
Usually glucose is
main “energy”
molecule enters
cellular respiration
Includes:
–
–
–
Glycolysis
Citric acid cycle
Electron transport
chain
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Ecocyc—database of complete E. coli metabolism
E. Coli
Metaobolism
website
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Mitosis—cell division
• Why do cells divide?
– Growth—so tissues/structures can become
larger
– Replacement—many tissues are constantly
being replaced because they get worn out or
used up. E.g. blood, skin, lining of gut, sperm
– Repair—when tissues get damaged due to
injury
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Mitosis—what happens (overview)
• DNA/chrosomes replicate
(make exact copies
• Copies line up at center
of cell
• Copies pulled to opposite
ends of cells by
centromeres/spindles
• Cell membrane pinches
off and splits cell into two
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
This initial review of life and cells is crucial!
• Please read your book chapters, review
the web links and get this part of the
course.
• We’ll come back to cells and how they
work again and again.
• I am aware this is a LOT of information!
• But master this, and the rest of the course
will seem easy.
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College