cellular respiration: day 04 process whereby cells breakdown glucose and other food molecules to...
Post on 24-Dec-2015
229 Views
Preview:
TRANSCRIPT
Cellular Respiration: Day 04
Process whereby cells breakdown glucose and other food molecules to release energy.
Updates
• We will test on Cellular Respiration before moving onto Photosynthesis
• Test will be next week sometime– When? It depends on if we miss school for the
elections or not – check our WIKI!!
• Lab – Lets talk about that first!
Lets Review the Cellular Respiration Cycle
• Lets begin with a Respiration Tutorial– Take a look at the big picture!
• When you exercise:
– Muscles need energy in order to perform work.
– Enzymes in muscle cells help the cell convert glucose and oxygen into ATP (usable energy).
• Terms we have discussed: – Aerobic Metabolism– Anaerobic Metabolism– Autotrophs– Heterotrophs– Producers– Consumers
• The ingredients for photosynthesis are carbon dioxide and water.
– CO2 is obtained from the air by pores on a plant’s leaves.
– H2O is absorbed from the damp soil by the roots.
– Veins transport the water from roots to leaves.
• Chloroplasts rearrange the atoms of these ingredients to produce sugars (glucose) and other organic molecules (key products = glucose and oxygen).– Oxygen gas is a by-product of photosynthesis
Chemical Cycling Between Photosynthesis and Cellular Respiration
• Cellular respiration:
CELLULAR RESPIRATION: AEROBIC HARVEST OF FOOD ENERGY
– The main way that chemical energy is harvested from food and converted to ATP
– This is an aerobic process—it requires oxygen
A common fuel molecule for cellular respiration is glucose.
• This is the overall equation for what happens to glucose during cellular respiration.
Glucose Oxygen Carbondioxide
Water Energy
• Cellular respiration can produce up to 38 ATP molecules for each glucose molecule consumed.
• Cellular respiration is an example of a metabolic pathway (a series of chemical reaction in cells).
• All of the reactions involved in cellular respiration can be grouped into three main stages:
1. Glycolysis
2. The Krebs cycle
3. Electron transport
The Metabolic Pathway of Cellular Respiration
• Why does electron transfer to oxygen release energy?
– When electrons move from glucose to oxygen, it is as though they were falling
– This “fall” of electrons releases energy during cellular respiration
Figure 6.5
Releaseof heatenergy
• The path that electrons take on their way down from glucose to oxygen involves many stops
NADH and Electron Transport Chains
Figure 6.6
1/2
(from food via NADH)
2 H 2 e
Energy forsynthesis
of
Electro
n tran
spo
rt chain 2 e
2 H1/2
A Road Map for Cellular RespirationCytosol
Mitochondrion
High-energyelectronscarriedby NADH
High-energyelectrons carriedmainly byNADH
Glycolysis
Glucose2
Pyruvicacid
KrebsCycle
ElectronTransport
I. Glycolysis (click)Process whereby one glucose molecule is broken in half
producing two pyruvate molecules.
• Takes place in cell’s cytoplasm.
• Does not require O2 to take place.
• Occurs very rapidly, however, low energy yield (Net 2 ATP and 2 NADH produced)
Mitochondria
Site of Krebs cycle and Electron Transport Chain
II. Krebs Cyle (click)Process whereby pyruvate is broken down into CO2 in a
series of energy releasing reactions.
• Only occurs if O2 is present (aerobic respiration).
• Takes place within the mitochondria of the cell.
• Each pyruvate that goes through the cycle produces 1 ATP, 4 NADH, 1 FADH2 and 3 CO2 (2 X that amount for each glucose molecule).
III. Electron Transport Chain (click)Uses the high energy electrons from NADH and FADH2 to
convert ADP into ATP.• Occurs in proteins that are embedded within the inner membrane of the mitochondria.
• As high energy electrons from NADH and FADH2 are passed from protein to protein in the “chain”, H+ ions are pumped across the membrane.
• H+ ions flow back through ATP synthase which converts ADP into ATP.
• Final electron acceptor in the “chain” is O2 forming a H2O molecule.
• 10 NADH and 2 FADH2 make a total of 34 ATPs.
Adding Up the ATP from Cellular Respiration
Figure 6.14
Cytosol
Mitochondrion
Glycolysis
Glucose2
Pyruvicacid
2Acetyl-
CoA
KrebsCycle Electron
Transport
bydirectsynthesis
by directsynthesis
byATPsynthase
Maximumper
glucose:
The Versatility of Cellular Respiration
• Cellular respiration can “burn” other kinds of molecules besides glucose.
– Diverse types of carbohydrates– Fats– Proteins
FERMENTATION: ANAEROBIC HARVEST OF FOOD ENERGY
• Some of your cells can actually work for short periods without oxygen.
– For example, muscle cells can produce ATP under anaerobic conditions.
• Fermentation– The anaerobic harvest of food energy
Without Oxygen!!!
• We cannot enter the Krebs Cycle
• Must use Anaerobic Respiration– Alcohol Fermentation– Lactic Acid Fermentation
In order for Glycolysis to continue NAD+ must be present.
• Without O2 (anaerobic respiration) the NADH can not move onto the Krebs cycle.
• Think of NADH as “full moving trucks” which must be unloaded for the company to survive.
Like our lab!!
2 ways to “unload” the NADH in anaerobic environments
• Alcohol Fermentation NADH passes electron back to pyruvic acid creating alcohol molecules. Occurs in yeast and other microorganisms
• Lactic Acid Fermentation NADH passes electron back to pyruvic acid creating lactic acid molecules. Occurs with our muscle cells and other prokaryotes (helps make yogurt, kimchi and cheese!)
• Human muscle cells can make ATP with and without oxygen
– They have enough ATP to support activities such as quick sprinting for about 5 seconds
– A secondary supply of energy (creatine phosphate) can keep muscle cells going for another 10 seconds
– To keep running, your muscles must generate ATP by the anaerobic process of fermentation
Fermentation in Human Muscle Cells
• Glycolysis is the metabolic pathway that provides ATP during fermentation.
– Pyruvic acid is reduced by NADH, producing NAD+, which keeps glycolysis going
– In human muscle cells, lactic acid is a by-product
2 ADP+ 2
Glycolysis
Glucose
2 NAD
2 Pyruvicacid
+ 2 H
2 NAD
2 Lacticacid
(a) Lactic acid fermentation
• Various types of microorganisms perform fermentation.
– Yeast cells carry out a slightly different type of fermentation pathway
– This pathway produces CO2 and ethyl alcohol
Fermentation in Microorganisms
Figure 6.15b
2 ADP+ 2
2 ATPGlycolysis
Glucose
2 NAD
2 Pyruvicacid
2 CO2 released
+ 2 H
2 NAD
2 Ethylalcohol
(b) Alcoholic fermentation
• Respiration tutorial– Both high and low oxygen settings– Copy and paste the questions into your
onenote and answer there. – Read the blurb at the beginning of each
section before pressing play.
Images Citedhttp://www.mir.com.my/rb/photography/companies/canon/fdresources/fdlenses/vinpix/swimmer.jpghttp://www.maratonasant-antonio.com/upload/file_ima_8ce13b8605.jpghttp://www.nationalgeographic.com/adventure/images/0609/everest-thomas-pemmba.jpghttp://www.msu.edu/course/isb/202/ebertmay/images/Energy%20Proc%20PNG.pnghttp://www.kidsco.co.uk/Entertainer%20Images/Fire%20Eater.gifhttp://www.chinadaily.com.cn/english/doc/2005-02/04/xin_530202021019679268915.jpghttp://www.topicsites.com/health-fitness/woman-eating-apple.jpghttp://www.nhnr.org/wcheal/images/Ingredients_Healthy_Food.jpghttp://www.stationnight.com/Homer-Sleep1.gifhttp://dept.kent.edu/projects/cell/tly1.jpghttp://www.a3243g.com/a3243g_images/mitochondria.gifhttp://kentsimmons.uwinnipeg.ca/cm1504/Image110.gifhttp://staff.jccc.net/pdecell/bio122/glycolysis.gifhttp://www.biologycorner.com/resources/fermentation.jpghttp://images.jupiterimages.com/common/detail/53/04/23360453.jpghttp://images.jupiterimages.com/common/detail/11/81/23268111.jpghttp://www.trifood.com/image/kimchi_image_final.JPGhttp://www.thefinalsprint.com/images/2007/01/lactic-acid-training.jpghttp://faculty.ircc.edu/faculty/tfischer/images/Krebs%20overview.jpghttp://student.ccbcmd.edu/~gkaiser/biotutorials/energy/images/chemios_il.jpghttp://fig.cox.miami.edu/~cmallery/150/makeatp/c9x6cell-respiration.jpg
top related