made up of anabolism

synthesis or building up ---needs energy

and catabolism

degradation or tearing down---release energy

is a catabolic process -- food fuels are broken down in the cell

some of energy released is captured

some atoms used in other processes

repairing, growing, secreting, 

the usual cellular shuttle for energy

enzymes take the high-energy phosphate group from ATP and move it to other molecules

those molecules are said to be PHOSPHORYLATED

this allows the molecule to change 

work is done, motion occurs

. digestion in GI tract – small particles enter circulation and are distributed to cells

2. inside the cell the nutrients are used to build (anabolism) or are broken down (glycolysis)

3. inside the mitochondria final harvesting of energy, breakdown of pyruvic acid

carbon dioxide and water are produced and ATP is loaded up

inside the mitochondria final harvesting of energy, breakdown of pyruvic acid

carbon dioxide and water are produced and ATP is loaded up

step three = called CELLULAR RESPIRATION

so this is how your food provides you with energy

cells do the final breakdown of glucose and fatty acids into usable energy 

or the glucose and fatty acids are used to build glycogen, cellular parts, lipids as needed (step 2)

step three = called CELLULAR RESPIRATION

so this is how your food provides you with energy

cells do the final breakdown of glucose and fatty acids into usable energy 

or the glucose and fatty acids are used to build glycogen, cellular parts, lipids as needed (step 2)

these take specific organic molecules

process and harvest energy

out in the cytosol larger molecules are broken down into these usable forms for the mitochondria

the mitochondria finish the job

using citric acid cycle and electron transport chain (ETC)

most cells like carbs for a quick source of energy

basic formula =

glucose +  oxygen      carbon dioxide   +  water

plus energy is loaded on a shuttle

glucose is broken down  SLOWLY……

you harvest a net of 36 ATP molecules (loaded up)

process begins in cytosol and moves to mitochondria

glycolysis is beginning process – no oxygen required yet

the first step in taking glucose apart to harvest its energy

pyruvic acid (pyruvate) is result

process done by enzymes

this costs some energy, but when finished it is 2 ATP ahead

occurs out in cytosol because glucose doesn’t enter the 

if no oxygen -  fermentation

lactic acid build up

and little energy is harvested yet

if you have enough oxygen, the mitochondria will absorb the pyruvate

deposit it in the center – matrix

there it is altered

carbon dioxide is removed

a carrier is loaded with hydrogen (NAD)

Coenzyme A is added…

what is left is acetyl-CoA  (no more pyruvate)

now enzymes drive the citric acid cycle

if you have enough oxygen, the mitochondria will absorb the pyruvate

deposit it in the center – matrix

there it is altered

carbon dioxide is removed

a carrier is loaded with hydrogen (NAD)

Coenzyme A is added…

what is left is acetyl-CoA  (no more pyruvate)

now enzymes drive the citric acid cycle

what’s the point???

to remove hydrogen atoms

transfer them to carriers

carbon dioxide is a waste product

little energy is harvested yet

but…carriers are loaded with hydrogen atoms

are proteins embedded in the inner membrane – grouped together

they gradually strip the energy off the hydrogens 

pumps send the hydrogens to the out area

this is where you generate the majority of ATP

conditions here create a steep concentration gradient of hydrogen ions

across the inner membrane

electrons are passed along the system

release energy

this energy drives hydrogen ion pumps which move the hydrogen ions to outer area

as the hydrogen is passed down the series of carriers

some energy is stripped from it

pumps eject the proton

a bit of energy is stripped by the carriers until the low energy electrons are left at the end

hydrogen protons move through a channel that generates kinetic energy to load up an ADP molecule to ATP

the left over hydrogen, + electrons, + nearby oxygen = make WATER

glycolysis – 

harvests a little energy

pyruvate is end product

takes place in cytoplasm

cellular respiration

harvests large amount of energy

together with glycolysis = 36 ATP loaded

end product is WATER

takes place in mitochondria

glycolysis – 

harvests a little energy

pyruvate is end product

takes place in cytoplasm

cellular respiration

harvests large amount of energy

together with glycolysis = 36 ATP loaded

end product is WATER

takes place in mitochondria

cells prefer glucose as a quick source of energy

it is burned first –with second choice being lipids and last choice – proteins

if your diet doesn’t include enough glucose, your liver will take glycogen and ‘dismantle’ it into the monomer glucose

called GLYCOGENOLYSIS

if your diet included TOO MUCH glucose the liver will reverse that to create glycogen - GLYCOGENESIS

now think in molecules smaller than glucose – not building from glucose or breaking down to glucose…..

your cells can’t reverse the glycolysis steps to make glucose

they use other enzymatic pathways to create glucose – from other molecules

so if there isn’t enough glucose available, the cells can provide it in different ways 

lypolysis

into pyruvate and fatty acids

put in citric acid cycle

two-carbon fragments are harvested for energy – much more ATP is loaded than for carbohydrates

although they provide large amounts of energy – that energy is not as easily retrieved  - takes longer to get large amounts of energy 

you burn carbs when energy demands are immediate

begins with acetyl-CoA

easy to make fats from any food eaten

to make fatty acids for building

Lipogensis -lipids, amino acids, carb can be converted to acetyl-CoA to make other lipids

some fatty acids cannot be made (essential)

need to eat foods

recall some of the uses of fats in the body…….

Chylomicrons -  largest, made in intestinal cell

mostly triglyceride – come from food

rest of the four groups are made in liver

VLDL

triglycerides plus small amounts of phospholipids and cholesterol

transport triglycerides to your various tissues

Intermediate-Density Lipoproteins (IDL)

less triglycerides

LDL – deliver cholesterol to tissues- have some protein

HDL about equal lipid and protein (allow density) 

mop up excess cholesterol and return it to liver

if carbs and fatty acids are not available, you will break down amino acids for energy

more difficult than carbs or lipids to dismantle

one by-product is toxic (ammonium ions)

cell prefers to safeguard its proteins structures and enzymes

deamination is removal of an amino group, but ammonium ions are generated

liver uses these to make urea

you can create some amino acids from basic atoms to make polypeptides

some are essential – get from food