Quick and Long Energy

Chapter 7

• Cells cannot get enough oxygen• Build up of pyruvic acid and NADH and no oxygen to break it down• Cells begin fermentation

– Lactic Acid fermentation• Pyruvic acid + NADH lactic acid + NAD+• Get about 90 seconds of energy without having to use oxygen• HOWEVER, oxygen will be paid back double when you are done

(think heavy breathing)• Occurs in muscle cells, and microorganisms, such as the ones that

turn milk into cheese and yogurt• Lactic acid causes muscle cramping and burning sensation• Oxygen is required to break down lactic acid and get it out of body

– Alcohol fermentation• Pyruvic acid + NADH ethyl alcohol + NAD+• Occurs in yeast cells and other microorganisms, such as the ones

involved in the production of bread and wine

Quick Energy• 3 ways to obtain energy

– ATP stored in muscles (glycogen) (short)– ATP from lactic acid (short)– ATP from cellular respiration (long)

• Cells initially have small amount of ATP from cell resp. and glycolysis• Think of running a 200 m sprint

– Gun goes off• Muscles of runner contract, turning glycogen in muscle cells into glucose,

but this only provides for a few seconds of intense activity– You pass the 50m mark

• most ATP the was initially stored is now gone• Muscle cells are producing ATP from lactic acid fermentation• This lasts about 90 seconds

– End of Race• Lots of lactic acid build up• Only way to get rid of lactic acid is a chemical pathway that requires oxygen• Thus, at the end of the race, you are breathing heavily and you should follow

an intense work out with a slow jog

Long Term• Energy for running long races or other endurance sports

• Cellular respiration is the only way to get enough ATP to last the length of the race

• Cellular respiration makes ATP more slowly than lactic acid fermentation

• Athletes must pace themselves

• Glycogen an important molecule– Carbohydrate

– Polysaccharide (monosaccharide is glucose)

– Muscle and liver cells store E as glycogen

– Glycogen is broken down by the hormone Glucagon

– Glycogen break down is also stimulated by muscle contraction• When you work out, muscles contract and they can use energy stored in glycogen

– Increase glycogen storage, increase the duration of exhaustive work your muscles can do

– Stores of glycogen last about 15-20 minutes

• After glycogen is used up, body starts to break down other molecules to get energy– Fats and proteins

– Fatty acids are broken down and carried to mitochondrial matrix and enter the membrane in fragments as acetyl-CoA

– Proteins are broken down into aa and the these modified aa’s are fed back into the Krebs cycle (NAD+ and FAD)

• Aerobic exercise is good for weight control because it leads to break down of fats

Training to Improve Function of ATP production

• Anaerobic training– Increase levels of glycogen in muscle cells

and increase tolerance of lactic acid build up

• Aerobic training– Increases size and number of mitochondria in

muscle cells and increase delivery of oxygen to muscle cells by improving heart and lung efficiency