Cellular Respiration

Chapter 5 Notes

Some Terms to Know

Aerobic = WITH oxygen

Anaerobic = withOUT oxygen

NAD+ electron carrier = NADH

FAD electron carrier = FADH2

Cellular Respiration a way for cells to make

energy when oxygen is present

Fermentation a way for cells to make energy

when oxygen is not present

Cellular Respiration Overview

Transformation of chemical energy in food into

energy cells can use in the form of ATP

Overall Reaction:

C6H12O6 + 6O2 6CO2 + 6H2O + ATP (energy)

Decomposition Reactionwhy?

Hydrolysis

When water is

inserted into a

bond to break it!

Most biological

decomposition

reactions involve

hydrolysis

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Cellular Respiration in 3 Stages

Glycolysis in cytoplasm of cell

Krebs Cycle in the mitochondrial matrix

Electron Transport Chain after the Krebs Cycle

and in the cristae (membranes) of mitochondria

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Cellular Respiration Overview

Breakdown of glucose begins in the cytoplasm

Then energy is made in one of two pathways

Anaerobic cellular respiration (aka fermentation)

Aerobic cellular respiration

Diagram of the Reaction

C.R. Reactions

Glycolysis Requires 2 ATP molecules

- Occurs in cytoplasm of all cells

Series of reactions that break glucose molecule down

into two 3-carbon molecules called pyruvate (aka

pyruvic acid)

Gains 2 ATP molecules for every one glucose

molecule broken down

Gains 2 NADH per glucose molecule

All organisms from simple bacteria to humans perform

it the same way

Glycolysis Reaction

Glycolysis Reaction Cont.

Anaerobic Cellular Respiration /Fermentation

Some organisms thrive in environments with little or no oxygen

Marshes, bogs, gut of animals, sewage treatment ponds

No oxygen used= anaerobic

Results in no more ATP after glycolysis, final steps in these

pathways serve ONLY to regenerate NAD+ so it can return to pick up

more electrons and hydrogens in glycolysis.

Occurs in cytoplasm

End products such as ethanol and CO2 (single cell fungi (yeast) in

beer/bread) or lactic acid (muscle cells)

Aerobic Cellular Respiration

Oxygen required=aerobic

2 more sets of reactions that occur in the

mitochondria

1. Krebs Cycle

2. Electron Transport Chain

Krebs Cycle

Completes the breakdown of glucose

Takes the pyruvate (3-carbons) and breaks it down.

The carbon and oxygen atoms end up in CO2 and H2O

Hydrogens and electrons are stripped from the

pyruvates and loaded onto NAD+ and FAD to produce

NADH and FADH2 (reduction).

Only 2 more ATP are made but loads of NADH

and FADH2 with H+ and electrons, which move to

the 3rd stageETC

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Electron Transport Chain

Electron carriers are loaded with electrons and

protons from the Krebs cycle and move to this

chain-like a series of steps (staircase).

As electrons drop down stairs, energy released

to form a total of 34 ATP

Oxygen waits at bottom of staircase, picks up

electrons and protons and in doing so becomes

water

Electron Carriers

NAD + electrons = NADH

FAD + electrons = FADH2

NADH is worth 3 ATP in the ETC

FADH2 is worth 2 ATP in the ETC

Energy Tally

38 ATP for aerobic vs. 2 ATP for anaerobic

Glycolysis 2 ATP

Krebs 2 ATP

Electron Transport 34 ATP

38 ATP

Anaerobic organisms cant be too energetic but are important for global recycling of carbon

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http://www.brookscole.com/chemistry_d/templ

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ions/oxidative/oxidativephosphorylation.html

http://www.wiley.com/legacy/college/boyer/04

70003790/animations/electron_transport/electr

on_transport.htm

Cellular Respiration - heat

Cell Resp. releases some

energy as heat which help

keep our internal temps

constant.

Brown fat- more

mitochondria so faster CR

and more heat = important

for hibernating animals and

infants

Cellular Resp-heat production in

plants Some plants produce

enough heat energy

so that organic

compounds break

down, causing an

odor. Insects flock to

the odor plant gets

pollinated

Mitochondrial Disease

Diseases of the mitochondria appear to

cause the most damage to cells of the

brain, heart, liver, skeletal muscles, kidney

and the endocrine and respiratory

systems. http://www.umdf.org/site/pp.aspx?c=8qKOJ0MvF7LUG&b=7934629

http://www.umdf.org/site/pp.aspx?c=8qKOJ0MvF7LUG&b=7934629

More Mitochondrial Functions

Non-ATP-related functions are intimately involved with most of the

major metabolic pathways used by a cell to build, break down, and

recycle its molecular building blocks. Cells cannot even make the

RNA and DNA they need to grow and function without mitochondria.

The building blocks of RNA and DNA are purines and pyrimidines.

Mitochondria contain the rate-limiting enzymes for pyrimidine

biosynthesis (dihydroorotate dehydrogenase) and heme synthesis

(d-amino levulinic acid synthetase) required to make hemoglobin. In

the liver, mitochondria are specialized to detoxify ammonia in the

urea cycle. Mitochondria are also required for cholesterol

metabolism, for estrogen and testosterone synthesis, for

neurotransmitter metabolism, and for free radical production and

detoxification. They do all this in addition to breaking down

(oxidizing) the fat, protein, and carbohydrates we eat and drink.

Facultative aerobes - Can survive for

longs periods of

time with or without

oxygen

They switch back

and forth between

cell resp &

fermentation

depending on the

availability of

oxygen

Ex: staph/ecoli

Obligate Anaerobes-

Does not require

oxygen and only lives

in an anaerobic env.

Use fermentation/

anaerobic respiration

to yield energy

Much less ATP is

made this way

EX: Clostridium

bacteria

Obligate Aerobes-

REQUIRE oxygen

for respiration or

they wont live

Yield much more

energy than

obligate

anaerobes

EX: plants,

animals

Nutrient Cycles

Biogeochemical cycles

Chemicals are limited, those essential for

life must be recycled.

Elements move through a global cycle

(carbon dioxide, oxygen, and nitrogen)

Phosphorous and sulfur dont move much

stick around in the soil.

Carbon Cycle, Nitrogen Cycle, Water cycle

The Carbon Connection

Photosynthesis uses it (all photosynthetic

organisms)

CR creates it (so, all living things)

Cars, factories, appliances emit it

Decaying organic matter releases it

Adds to global warming

OhhhhCarbon

Carbon is the backbone of life on Earth. We are made of

carbon, we eat carbon, and our civilizationsour

economies, our homes, our means of transportare

built on carbon. We need carbon, but that need is also

entwined with one of the most serious problems facing

us today: global climate change.

Carbon is the fourth most abundant element in the

Universe. Most of Earths carbonabout 65,500 billion

metric tonsis stored in rocks. The rest is in the ocean,

atmosphere, plants, soil, and fossil fuels

http://www.google.com/url?sa=i&rct=j&q=label+the+carbon+cycle&source=images&cd=&cad=rja&docid=sv-fkAQg9v3esM&tbnid=CVE5aqzHecHkPM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.sciencelearn.org.nz%2FContexts%2FThe-Ocean-in-Action%2FSci-Media%2FAnimations-and-Interactives%2FCarbon-cycle&ei=pCQIUbPEI4br0QHAl4DoAg&bvm=bv.41524429,d.dmQ&psig=AFQjCNGiy_nmGQhh8-qrj5eanfzHl__CxA&ust=1359574565039202

Your carbon footprint?

Carbon Credits

http://www.google.com/url?sa=i&rct=j&q=how+do+carbon+credits+work%3F&source=images&cd=&cad=rja&docid=6FexCPGSyd5gEM&tbnid=8HJvsrbFNgceAM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.greenbrideguide.com%2Fcarbonfree-carbonfundorg&ei=szcIUcW8L7K40AHQqoGIAw&psig=AFQjCNELOQIVVanjUesG8gRSWSuai8N4cA&ust=1359579444332858http://www.google.com/url?sa=i&rct=j&q=how+do+carbon+credits+work%3F&source=images&cd=&cad=rja&docid=SV2ILaOcnYv-ZM&tbnid=HNn_xA4YElb-UM:&ved=0CAUQjRw&url=http%3A%2F%2Funambig.com%2Fcarbon-credits-chosen-over-kids-in-b-c%2F&ei=szcIUcW8L7K40AHQqoGIAw&psig=AFQjCNELOQIVVanjUesG8gRSWSuai8N4cA&ust=1359579444332858