Respiration Chapter 6. Cellular Respiration - Basics releases energy from glucose released energy is...

Respiration

Chapter 6

Cellular Respiration - Basics

• releases energy from glucose• released energy is chemical energy• occurs in cell

cytoplasmmitochondria

• works better with oxygen (aerobic) than without oxygen (anaerobic)

Cellular Respiration - Process

glucose oxygen +water energycarbon dioxide ++

CO2C6H12O6 H2OO2 ATP+ + +

Aerobic Respiration

aerobic = with oxygenC6H12O6 + O2 -----> CO2 + H2O + ATP

Three process occur in aerobic respiration1. Glycolysis

occurs in the cytoplasm

oxygen is not requiredelectron acceptor is nicotinamide adenine

dinucleotideNAD --> NADH

glucose 2 pyruvic acid

CCC

CCC

CCC C

CC

PEP

CO2

Aerobic Respiration cont’d

2. Krebs Cycle (citric acid cycle)

pyruvic acid(3C)

(in cytoplasm)

acetyl-coenzymeA(2C)

(in mitochondron)

Krebs Cycle

CO2

CO2

ATP

NADH

FADH2

occurs in:

mitochondria

electron acceptors are

NAD and FADH2

CCC

CC

C

C

C

Kreb’s Cycle

Aerobic Respiration cont’d

3. Electron transport• electrons transferred from

NADH, FADH2 to oxygen and water is formed

• oxidative phosphorylation• ATP synthase complex• protons pumped across

membrane

• occurs in mitochondria• conversion equivalents:

NADH = 3 ATPFADH2 = 2 ATP

Aerobic Respiration cont’d

• Energy from aerobic respiration• Glycolysis

• net gain of 6 ATP

• pyruvic acid --> acetyl-CoA• 2 NADH = 6 ATP

• Krebs Cycle• 2 ATP

• Electron Transport• 6 NADH = 18 ATP• 2 FADH2 = 4 ATP

• oxidative phosphorylation

•Total = 36 ATP / glucose

•39% of energy available

•61% of energy is lost as heat

Anaerobic Respiration

(without oxygen)

1. ethanol fermentation

glucose ---> pyruvic acid ---> ethyl alcohol + CO2 + ATP

C6H12O6 ----> 2C2H5OH + 2CO2 + 3ATP

• 25% of energy of aerobic respiration

• occurs in some plants and microorganisms including yeasts

Alcohol Fermentation• Ancient Eqyptian wall painting: historical record of wine-

making• ~ 5000 yrs ago, perhaps earlier• Grapes were picked, crushed by foot, juice collected in jugs,

then fermented producing wine.

Anaerobic Respiration cont’d

2. lactic acid fermentation glucose ---> pyruvic acid ---> lactic acid + ATP

C6H12O6 ----> 2C3H6O3 + 2ATP

• 22% of energy of aerobic respiration

• mammalian muscle and some microorganisms

Organic Macromolecules

• four groupsCarbohydrates

built from monosaccharidesProtein

built from amino acidsLipids

built from glycerol & fatty acidsNucleic acids

built from nucleotides

Carbohydratesmonosaccharides

disaccharides

polysaccharide

Lipids

Protein

Biochemical Pathways

• note catabolic and anabolic pathways

• note production and use of:• proteins• lipidsbesides carbohydrates

What is the connection between respiration and photosynthesis?

A review:

Carbon flow: • from atmosphere• through photosynthesis in autotrophs• through cellular respiration in autotrophs

and heterotrophs• back into atmosphere

Carbon atom movement. Numbers are estimates of carbon expressed in billions of metric tons stored in reservoirs (2000 data)

Carbon released by respiration and combustion now exceeds the amount fixed by photosynthesis, by 3 billion metric tons/year.

Carbon Cycle

CARBON + OXYGEN -> CO2 + heat

Major reservoirs of the carbon cycle

Production of CO2

• fossil fuels produces 70% of CO2 emmisions• U.S. 24%• EU 15%• China 15%• Russia 6%• India 5%• Japan 5%

• per capita CO2 emmissions (tons/capita)• U.S.

5.4• EU

2.6• China

0.8• Russia

2.9• India

0.3• Japan

2.5

http://upload.wikimedia.org/wikipedia/en/b/bf/Carbon_Emission_by_Region.png

http://upload.wikimedia.org/wikipedia/en/5/56/Global_Carbon_Emission_by_Type.png

Global Response to global warming

• Kyoto Protocol• protocol to the

international Framework Convention on Climate Change with the objective of reducing Greenhouse gases that cause climate change

• agreed on 11 December 1997 at the 3rd Conference of the Parties to the treaty when they met in Kyoto, and entered into force on 16 February 2005.

• United States although a signatory to the Kyoto Protocol, has neither ratified nor withdrawn from the Protocol

• both Clinton and Bush administrations have refused obtain senate ratification

• reasons:• top emitters excluded (China,

India)• cause U.S. economic strain to

meet requirements

Participation in the Kyoto Protocol, as of December 2011,Brown = Countries that have signed and ratified the treaty              (Annex I & II countries in dark brown)Blue = No intention to ratify at this stageDark blue = Canada, which withdrew from the Protocol in December 2011Grey = no position taken or position unknown

Correlation Between Historic CO2 Levels and Historic Temperatures: Ice core data

31

http://cdiac.esd.ornl.gov/Carbon Dioxide Information Analysis Center

Air samples at Mauna Loa, Hawaii are collected continuously from air intakes at the top of four 7-m towers and one 27-m tower. Four air samples are collected each hour for the purpose of determining the CO2 concentration

Global Temperature Change

How well does CO2 predict global temperature?

What Causes Natural Climatic Swings?• Modest climate

changes correspond to an 11-year cycle in the Sun’s intensity

• Milankovitch Cycles are caused by changes in the Earth’s orbit (100,000 yr), rotation (40,000 yr) and the wobble of its axis (26,000 yr)

9-35

temperature/precipitation changes from the 20th Century

Possible Implications of and Debate Surrounding Global Warming

• More heat waves• More extreme storm

activity• Changes in rainfall,

snowfall patterns• Ecosystem effects• Higher sea levels• More disease

• Winners: Siberia, Scandinavia

• Losers: most of U.S. (particularly SE; Washington may be nicer), island states

Fig. 09.13

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

New Orleans

Miami

Shoreline with 1 m sea-level rise

Remaining landCurrent shoreline

100 km50 km

Consequences of Global Warming

• uncertainty • why?• testing the predictions

• Probable environmental alterations from GW:• changing climate and

weather patterns• intensity of weather

increased• rising sea levels - 3’ higher

all around the world in 100 years

• shifting climate zones causing ecosystem devastation and species losses

Consequences of CO2 increase• CO2 as a Greenhouse Gas

• third most abundant gas in atmosphere

• absorbs heat energy reflected by earth• acts as a blanket around earth• produces the greenhouse effect

• This is normal, and good!

• Excessive greenhouse gas accumulation?• increase GH gas; increase

heat absorption• increased heat of earth• Global Warming

CO2 in atmosphere

• key component of nature’s thermostat

If carbon cycle removes too much CO2

earth cools

If carbon cycle generates too much CO2

earth warms

350.orgBecause the World Needs to Know

1. Cellular Respiration reactions are anabolic?

TrueFalse

2. The ultimate energy molecule produced in cellular respiration is

A. oxygenB. ATPC. glucoseD. ethanol

3. The final electron acceptor in cellular respiration is

A. NADP+B. oxygenC. ATPD. glucose

4. Without oxygen, which process in cellular respiration would NOT occur?

A. glycolysisB. Kreb’s cycleC. electron transportD. all of the above

5. Where does glycolysis occur?

A. cytoplasmB. inner mitochondrial

membraneC. chloroplastD. thylakoid

6. Where does Kreb’s cycle and electron transport occur?

A. cytoplasmB. mitochondriaC. chloroplastD. thylakoid

7. In cellular respiration all glucose is metabolized into ATP.

TrueFalse

8. Name the four groups of organic compounds and their respective building block(s):

organic compound building block(s)

1. 2. 3. 4.

9. Carbon reservoirs on earth include

A. atmosphereB. oceanC. plantsD. all of the above

What is the most abundant atmospheric gas?

A. nitrogenB. oxygenC. carbon dioxideD. ozone

What is the second most abundant atmospheric gas?

A. nitrogenB. oxygenC. carbon dioxideD. ozone

What is the third most abundant atmospheric gas?

A. nitrogenB. oxygenC. carbon dioxideD. ozone

How abundant is CO2 in the atmosphere?

A. 1000ppmB. 500ppmC. 390ppmD. 350ppm