Chapter 21

Photosynthesis

Endothermic reaction that requires energy to occur

Cellular respiration

Exothermic reaction that releases energy

Cellular respiration is the oxidation of foodstuffs into

CO2, H2O, ATP, and heat

Catabolism

Break down of large, complex molecules to provide energy and smaller molecules, such as the oxidation of carbohydrates, proteins, and lipids

Anabolism

Reactions that use ATP energy to build larger molecules or for muscle contration, transport, and synthesis of cellular compounds

Metabolite

Reactants/products of a metabolic pathway

The purpose of catabolism

To degrade food molecules into their building blocks or subunits so these subunits can be completely degraded into CO2, H2O, and ATP

The most used energy source

Carbohydrates

The currency of cells

ATP

Cells use an energy conversion strategy that uses many steps to

Conserve energy, reduce heat production, and many steps prevent damage to cells by heat

Where is energy harvested and stored

Bonds of ATP

What is ATP

A phosphoester bond joins the first PO4 group to the 5 carbon sugar ribose

Glycolysis degrades

The 6 carbon glucose into two 3 carbon pyruvate molecules

If glucose is the starting material it requires the breakage of

2 ATP bonds

If glycogen is the starting material it requires the breakage of

1 ATP bond

Glycolysis is a pathway for

Carbohydrate catabolism

Glycolysis occurs where

The cytoplasm

How many steeps occur in glycolysis and what are they catalyzed by

10 steps catalyzed by enzymes

What are the products of glycolysis

4 ATP, 2 NADH, 2 pyruvate

ATP is produced through

Substrate level phosphorylation

What is substrate level phosphorylation

A phosphoryl group is transferred to ADP from a phosphate containing molecule

What occurs at step 6

NADH must be re-oxidized back into NAD+ so glycolysis can continue

What is the limiting reagent in glycolysis

NAD+

When O2 is present…

The pyruvate will be converted into Acetly CoA which will feed the Krebs cycle

Glucose

2 ATPs are used in steps 1 and 3 to prime glucose for splitting

Glycogen

1 ATP is used in step 3 to prime glucose for splitting

What occurs at step 4

Fructose 1,6 BP splits into DHAP and Glyceraldehyde-3-phosphate, then DHAP is converted into a 2nd molecule of Glyceraldehyde-3-phosphate

What do the 2 Glyceraldehyde-3-phosphate account for

All 6 carbons found in the original glucose molecule

What two steps are the two ATP formed at

Steps 7 and 10

What step are the two pyruvates formed at

Step 10

What happens at the end of glycolysis when O2 is not present

Fermentation reactions

What do galactose and fructose form

Glycolysis pathway intermediates to enter the glycolysis pathway to be metabolized

Yeast fermentation products

2 Ethanol, 2 CO2, 2 NAD+

Muscle fermentation products

2 Lactate and 2 NAD+

Why do fermentation reactions occur

To reoxidize the 2 NADH produced in step 6 back into 2 NAD+ so that glycolysis can continue to produce ATP

What does pyruvate decarboxylate to and what are they reduced to

Acetaldehyde and CO2, which are then reduced by NADH into ethanol

What happens during strenuous exercise

The CVS cannot provide enough O2 to the cells for aerobic ATP production to occur

What happens when lactate builds up

The muscle cells form such a lactate build up that they can no longer function and glycolysis cannot continue, this is called anaerobic threshold

When exercise ceases

The liver takes up the lactate from the blood and converts it back into pyruvate, then glucose

When does the Cori Cycle occur

When oxygen levels increase after strenuous exercise stops

What can the liver do with this glucose

Carry it back to the muscles for immediate use to produce energy by way of glycolysis and then the krebs cycle OR as storage in the muscle tissues as glycogen

Blood sugar

Glucose, dextrose

Hypoglycemia

Low blood sugar

Hyperglycemia

High blood sugar

Glycogensis

Make/synthesis of glycogen

Gluconeogensis

Synthesize glucose from noncarbohydrate sources such as amino acids, lactate, or glycerol

Glycogenolysis

Breakdown of glycogen into glucose

Homeostasis

Maitenance of the internal enviroment within tolerable limts (temperature, pH)

Renal threshold

Amount overwhich a substance (glucose) is spilled into the urine for glucose

Glucagon

Increases blood sugar through the breakdown of glyogen into glucose, made in alpha cells of the pancreas

Epinephrine/adrenaline

Increases BS to muscles

Diabates mellitus

Abnormal carbohydrate, protein, and lipid metabolism that leads to hyperglycemia

Diabetes Type I

Insulin dependant, no or little insulin made

Diabetes Type II

Non-insulin dependent, adult onset, make insulin, but it does not work well

Diabetes symptoms

Increased hunger and thirst, decreased body weight

How do we decrease BS levels

Increase glycogen and fat storage, as well as urine output

Diabates associated disorders

Blindness, gangrene, neuropathy, kidney failure, CVD

Insulin

Made in B cells of the pancrease, released when BS levels are high

Insulin function

Most important regulator of metabolism, works on cells with insulin receptors and promotes anabolic reactions for storage of energy

Epinephrine and adrenaline are released when

There’s a decrease in BS to muscles, this increases the glucose supply to muscles

Glucagon is released when

BS levels are low, acts mostly on liver and adipose tissue, increases gluose supply to the body