BIO105-03

105lecture9notes

105lecture10notes

105lecture11notes

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Date:
Bio 105 Lecture 11 Notes
I. Types of Energy-Releasing Pathways
A. Aerobic                                       B. Anaerobic
II. Anaerobic Pathways
A. In mitochondria – no oxygen
B. In the cytoplasm – no oxygen
Date:
C. Fermentation in Us
1. Basic info
2. Lactate and “Muscle Burn”
D. Fermentation in Yeast

  • single-celled org w/ organelles like ours, live in solution
  • yeast w/ Ox = cell resp.
  • yeast w/o Ox = alcohol fermentation
    • glycoloysis: glucose -> pyruvic acid -> ethanol + CO2
  • alcohol can build to toxic levels

III. Versatility of Cell Respiration

  • Cellular respiration can burn other kinds of molecules besides glucose
    • diverse types of carb
    • fats
    • proteins

A. Carbohydrates

  • complete breakdown of a carb -> monosaccharides
    • glucose enters glycoloysis as is
    • galactose & fructose are modified to become a moleule in the glycolysis pathway – enter there
  • ~36-38 ATP/monosaccharide
  • CO2, H2O are byproducts

B. Fat

1. Basic Info

  • even though excess glucose is stored as fat – glucose cannot be made from fatty acids
  • triglycerides are broken into 2 parts
    • glycerol made into glucose
    • fatty acids: lipolysis breaks down long carbon chains into
      • AcetylCoA – enters sitric acid cycle
      • extra NADH and FADH2 – used in electron transport system

2. The end products of fat metabolism:

  • CO2 and H2O (cell resp)
  • ENERGY! -139 ATP from a 16C small fatty acid
    • from electron transport system (cell respiration)
    • remember – each triglyceride has 3 fatty acids

3. Fats vs. Carbs Energy

  • ATP per carbon atom
    • 6 C glucose = 38/6 = 6.3 ATP
    • 16 C fatty acid = 129/16 = 8 ATP per carbon
  • this shows that fat is a better store of energy than glucose

C. Protein
1. Basic info

  • proteins broken down to amino acids
  • amino acids are broken apart
    • amino group is removed – converted to urea and excreted
    • carbon backbones can enter any of the 3 stages of cell resp

2. End products of amino acid metabolism

  • CO2 & H2O (cell resp)
  • ATP (cell resp)
  • Nitrogen (excreted @ urea)

IV. “Disease of day”
A. Fainting
1. Basic info

  • if no oxygen foe extended period of time = faint
    • after 3 min, brain cells start to die, irreversible
  • drowning is similar
    • water fills lungs, blood gets little Ox
    • no Ox reaches brain
    • faint
    • still no Ox to brain

2. Fainting and cell respiration

  • what happens if O to brain is insufficient
    • Ox final electron acceptor of electron transport system
    • ATP runs out, no NAD + regenerated – citric acid cycle stops
  • conscious brain shuts down – faint, collapse
  • blood flows to brain = more Ox
    • electron trans system and citric acid cycle resume
  • lots of ATP produced again, regain consciousness

B. Cyanide poisoning

  • cyanide destroys electron transport system’s ability to transfer electrons and create H buildup
    • NADH, FADH2 accumulates, no ATP formes
    • brain cells run out of energy, die
  • AU 1982: 7 fatal Tylenol poisonings in Chicago
    • involved Ex-Str Tylenol laced with potassium cyanide
    • still haven’t caught/convicted killer

Clicker Questions
Which of the following is NOT a stage of cell respiration?
1.Glycolysis
2.Calvin cycle
3.Citric acid cycle
4.Electron transport system

Where in the cell does glycolysis occur?
1.Outside the mitochondria
2.In between the membranes of the mitochondria
3.In the matrix of the mitochondria
4.On the outer membrane of the mitochondria

Why does the citric acid cycle stop when there is no oxygen?
1.No ATP is made to keep it going
2.No oxygen to give electrons
3.No hydrogen to give electrons
4.No NAD+ to take electrons away

What provides the bubbles in beer and bread?
1.Bacteria
2.A bubbling machine
3.Grains
4.Yeast

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