Transcript 3/14 Cellular Respiration

3/17 Cellular respiration
1. What are the three stages of
cellular respiration? Name
them in order from first to last.
2. What is the overall equation
for cellular respiration?
Homework
 Protein synthesis quiz+ due tomorrow.
 CSR#6 due Thursday.
 Energy and metabolism quiz will be
handed out tomorrow and due
Thursday, no quiz+ option.
Cellular Respiration Review
 Summary sentence of cellular respiration:
Stage 1:
Stage 2:
Stage 3:
Cellular Respiration Review
 Cellular respiration is breaking down glucose to
get energy.
Glycolysis (in the cytoplasm)
Glucose (C6H12O6) broken down into two three-carbon
molecules, pyruvic acid. Charges some batteries; ATP
goes right to work in the cell, NADH goes to electron
transport. Charges the equivalent of 6 ATP.
Krebs Cycle (in the mitochondria)
2 pyruvic acids are broken down into 6 CO2. Charges
some batteries; ATP goes right to work in the cell, NADH
and FADH2 go to electron transport. Charges the
equivalent of 6 ATP.
Electron Transport
Keeping track of batteries
Battery
(uncharged ->
charged)
ADP -> ATP
NADP+ -> NADPH
NAD+ -> NADH
FAD -> FADH2
Stages of
photosynthesis
Stages of cellular
respiration
Keeping track of batteries
Battery (uncharged ->
charged)
Stages of photosynthesis Stages of cellular
respiration
ADP -> ATP
Charged in light
reactions, goes to
uncharge in Calvin cycle
NADP+ -> NADPH
Charged in light
reactions, goes to
uncharge in Calvin cycle
Charged in glycolysis,
Krebs cycle, electron
transport
NAD+ -> NADH
Charged in glycolysis and
Krebs cycle, goes to
uncharge in electron
transport
FAD -> FADH2
Charged in Krebs cycle,
goes to uncharge in
electron transport
Other pathways
 Aerobic vs anaerobic
Aerobic means “with oxygen.” Anaerobic
means “without oxygen.”
If conditions are anaerobic, glycolysis is
followed by fermentation rather than the
Krebs cycle.
Why can’t we do the Krebs cycle and electron
transport chain without oxygen?
Fermentation
 Fermentation breaks pyruvic acid down
to get energy, but isn’t as effective as
the Krebs cycle and electron transport.
 Two main types of fermentation:
Alcoholic fermentation and lactic acid
fermentation.
Fermentation
–
Lactic acid fermentation produces
lactic acid as a waste.
–
Example: Think about your muscle cells
when you’re running or working out…
Fermentation
 Alcoholic fermentation produces alcohol
and CO2 as a waste.
 Examples:
Bread rising. Yeast consumes sugar in
dough, and when it runs out of oxygen, it
ferments, giving off bubbles of CO2 that
form the air spaces in bread. The baking
process evaporates the alcohol.
Alcoholic fermentation
 Alcoholic beverages are also made by having
yeast ferment grapes (wine and brandy), grain
(beer, ale, whisky), potatoes (vodka), rice
(sake), cane sugar (rum), etc. The byproduct is
a kind of alcohol called ethanol.
 Alcoholic beverages are made in containers that can
let carbon dioxide out but don’t let air in - why?
Alcoholic Fermentation
 Ethanol biofuel.
 Alcoholic fermentation is one
way of producing ethanol from
corn or sugar cane. Microbes
consume the sugars in the
plant material and ferment
them.
 CO2 is produced, which is a
greenhouse gas. However,
because the plants uptake CO2
as well, it’s “canceled out”
which is one reason why
ethanol fuel is considered more
environmentally friendly than
fossil fuels.
Fermentation
 Fermentation breaks pyruvic acid down to get
energy, but isn’t as effective as the Krebs
cycle and electron transport.
 Two main types of fermentation: Alcoholic
fermentation and lactic acid fermentation.
 Alcoholic fermentation produces CO2 and alcohol
as wastes. It’s what causes bread to rise - when
the yeast in the dough runs out of oxygen, it
ferments, giving off bubbles of CO2 that form the
air spaces in bread. The baking process
evaporates the alcohol.
 Lactic acid fermentation produces lactic acid as a
waste. Think about your muscle cells when you’re
running or working out…
Other pathways
 And glucose is not the only way to get
and store energy. Other things we eat
that we might get energy from?
Other pathways
 Pyruvic acid can be converted back into
glucose or glycogen, but once you’re in the
Krebs cycle, you can’t go back.
 Lipids, glycogen, protein are other energy
sources besides glucose.
 Glycogen is a chemical battery, stores energy
long-term in the liver. Can be an alternative
outcome instead of going through glycolysis to get
pyruvic acid.
 Lipids are good for storing energy, proteins not so
much.
 Glucose energy can be stored as a lipid, instead of going
through the Krebs cycle and electron transport.
 Proteins aren’t good for storage, but they can be broken
down for energy if needed.
What you need to know of the
other stuff
 Know the names of the two types of
fermentation, what their waste products are
(easy if you know the name!) and in what
conditions they’re performed.
 Know the names of the other 3 molecules
that we can get energy from, and know that
glucose, fat, and glycogen can be converted
into each other, but protein can only be
broken down.
 You don’t need to know the details of the
fermentation stages, or the alternative
pathways. The only stages you need to know
are the big 3 - glycolysis, Krebs cycle,
electron transport.
Flowcharts/cartoons
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Using your notes, each group make two flowcharts
or “cartoons,” one of photosynthesis and one of
cellular respiration.
I will make copies of your group’s flowcharts so that
each of you can take it home with you tomorrow, so
put in all the details you might need for your quiz!
What are the stages?
Where do they happen in the cell?
What molecules enter the process, what happens to
them there, what do they leave as and where do they
go next?
Where is the original energy, at any given time?