Transcript PPT - Yavapai College

Cell Metabolism and Mitosis
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Cellular Respiration
Total cell metabolism
Diversity of Prokaryotic Cells
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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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?
• 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.
• Next slide: 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 can 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. Get the Folding@Home
Screensaver for your computer to help out.
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Overview of Diversity
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Prokaryotes—simple cells with no organelles
The primitive Archaea are frequently "extreme-ophiles," including these heat-tolerant forms that live
in hot springs
Electron micrograph of rod-shaped
bacteria--Bacillus?
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
• Typical shapes of
prokaryotic cells
• Cells are tiny—as
small as 1 micron
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Archaea
• Archaea are a group of
bacteria-like prokaryotes
that are believed to be
very close to the root of
the tree of life
• Characteristics of
Archaea (different from
bacteria):
Archaea in solar evaporation ponds near San Francisco
Bay--often have red or orange pigment to protect them
from intense solar energy
– Lack peptidoglycan in cell
wall
– Cell membrane lipids with
branched hydrocarbon
chains
– AUG start codon for
protein precursor is
methionine (like
eukaryotes) and not Nformylmethionine (like
bacteria)
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Archaea
Principally "extremophiles“
– live in harsh
environments:
– Thermophiles
– Halophiles--highly saline
habitats like Dead Sea,
Great Salt Lake and solar
evaporation ponds for salt
production
– Methanogens--obligate
anaerobes in high
methane environments-deep sea vents, colons of
animals, sewage
treatment plants
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
Bacteria Cell
Shapes and
Groupings
Cocci—rod-shaped bacteria
Bacilli—ball-shaped bacteria
Larry M. Frolich, Ph.D.
Biology Department, Yavapai College
• Lots of bacterial
groups!! Lots of
bacteria!!
• closeness of
disks shows
similarity of
rRNA sequence
See course website for link to images, descriptions of bacterial groups
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
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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:
–
–
–
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
Overview of Diversity
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