Nutrition Exam #3 (Unit 3: Ch. 7, 8, 19)

Anabolic reactions

require energy and build compounds

(anabolism)

Catabolic reactions

release energy and break down compounds

(catabolism)

Macronutrients that can be converted to pyruvate

Glucose, glycerol, and amino acids

Macronutrients that cannot be converted to pyruvate

Fatty acids. Can only be broken down to acetyl-Cola to provide E

How is energy captured in adenosine triphosphate (ATP)

Energy released from the break down (catabolism) of glucose, glycerol, fatty

acids, and amino acids is captured in adenosine triphosphate (ATP)

Liver functions

Metabolizes carbs, fats, and proteins, detoxifies, stores vitamins and minerals, activates vitamin D (w enzyme in liver), processes drugs (elicit and medical), helps dismantle old red blood cells and captures the iron for recycling

Where do macros go to be metabolized

Majority of macros go to the liver 1st, then the liver decides where in the body to send;

however, nutrients absorbed into the lymph go to the heart first, pumps them to the body’s cells, and the cells absorb the nutrients they need, the liver then handles the rest

Most metabolically active cells

Liver cells

How does the liver handle excess carbs

Stores excess carbs as Glycogen, triglycerides and releases carbs via glycogenolysis (breaking down glycogen)

Glucogenosis

Breaks down carbs (liver)

Glucogenosis

Makes glucose

Glucogenosis

Breaks down carbs (liver)

How does the liver handle excess proteins

Domination, makes nonessential amino acids

Metabolism of carbohydrates

In the liver: metabolizes fructose, galactose, and glucose (monosaccharides), makes and stores glycogen (glycogen sis), breaks down glycogen and releases glucose (glycogenolysis), makes glucose from some amino acids and glycerol when needed (gluconeogensis), converts excess glucose and fructose to fatty acids (high fructose corn syrup), breaks down glucose for energy when needed (glycolysis)

Glycogenesis

Making and storing glycogen (by liver)

Glycogenolysis

Breaks down glycogen and releases glucose

Gluconeogenesis

Makes glucose from some amino acids and glycerol when needed

non-alcoholic fatty liver disease (NAFLD) factor

High fructose corn syrup (HFCS) can promote NAFLD when liver converts excess glucose and fructose to fatty acids

Metabolism of lipids in the liver

Builds and breaks down triglycerides,

phospholipids, and cholesterol as

needed

• Breaks down fatty acids for energy when

needed

• Packages lipids in lipoproteins for

transport to other body tissues

• Manufactures bile to send to the

gallbladder for use in fat digestion

• Makes ketone bodies when necessary

Metabolism of proteins in the liver

Manufactures nonessential amino acids that are in

short supply

• Removes from circulation amino acids that are

present in excess of need and converts them to other

amino acids or deaminates them and converts them

to glucose or fatty acids

• Removes ammonia from the blood and converts it to

urea to be sent to the kidneys for excretion

• Makes other nitrogen-containing compounds the

body needs (such as bases used in DNA and RNA)

• Makes many proteins

First step of energy metabolism

break down macronutrients into pyruvate and/or acetyl-CoA

All energy nutrients (aka macronutrients) can be broken down to acetyl-CoA

acetyl-CoA (but not glucose)

Glycolysis steps of glucose breakdown

NADH (electron carriers) captures electrons when glucose is broken down, brings it to electron transport chain which generates most of the ATP we use from electron energy

NADH

(nicotinamide adenine

dinucleotide) is a coenzyme and

an electron carrier

Aerobic break down of pyruvate

Pyruvate to acetyl CoA

• Energy expenditure

proceeds at a slow to

moderate pace (jog)

• Yields energy in the

presence of oxygen

• High energy yield

Anaerobic break down of pyruvate

pyruvate to lactate

• Energy expenditure

proceeds quickly (sprint,

heavy lift, jumps)

• Yields energy without

oxygen

The break down of pyruvate can be

aerobic or anaerobic

lactate

dehydrogenase

converts

pyruvate to lactate

Cori cycle

converts lactate to glucose in the liver; The Cori cycle functions

to convert lactic acid

back to glucose so that it

can be reused by muscle

cells in need of quick

energy or stored as

glycogen if the muscle

activity has stopped.

The fate of pyruvate during aerobic vs

anaerobic respiration

TCA/citric acid cycle/Krebs cycle

Takes acetyl CoA, releases carbon dioxide/releases electrons that go to the electron transport chain, ends as pyruvate?

Electron Transport Chain

How many ATP per glucose molecule

30-32 ATP

Carbohydrate energy metabolism process (diagram)

subunits of proteins

amino acids

bonds to break amino acids + what does it + process

peptide bonds, protease, deamination

deamination

remove ammonia group from amino acid to yeild ammonia

ketoacid

any acid with a ketone group, rr>C=O

what is done with ammonia (NH3)

liver combines it with carbon dioxide to make much less toxic urea

maximum protein consumption

250 g/day, or you risk build up of urea

too much urea in the body

can lead to kidney disease

too much ammonia in the body

can lead to liver disease

transamination

liver makes nonessential amino acids from keto acids; body dismantles its own proteins to get essential amino acids

glucogenic amino acids

can be used to make glucose (converted to pyruvate first); most amino acids are glucogenic

95% of fat we consume/energy

triglycerides

why do fats carry more energy than carbohydrates?

fats have more carbon bonds, more energy

triglyceride break down

triglycerides > glycerol+ fatty acids > pyruvate + acetyl-CoA

lipolysis

hydrolysis of fats (like triglycerides) to form glycerol and fatty acids

Lipase

enzyme performs lipolysis (hydrolysis of lipids)

Glycerol is broken down to

pyruvate

Fatty acids are broken down into

acetyl coA via beta oxidation.

Beta oxidation

the process of breaking down fatty acids into acetyl-CoA (occurs in the mitochondria) - by chipping away 2 carbons at a time (carbon # doesnt matter for this class)

process of forming urea

the liver combines ammonia and CO2 to make less toxic urea

all energy-yielding nutrients can be broken down into

acetyl-CoA

Acetyl-CoA can

enter the TCA/Kreb’s Cycle or it can be used to make fat

what does the ETC use (electron transport chain)

reactions that breakdown macros release hydrogen atoms with their electrons which are carried by coenzymes to the ETC

Some cells run exclusively on glucose as a fuel source, such as some neurons. If the body had no glucose available, what would happen? What alternative fuel sources could be used for glucose?

you would have to make glucose:

• glycerol from fats (triglycerides) to make glucose

• glucogenic amino acids to make glucose

• break down glycogen from the liver to make glucose

main end result summary of breakdown of macros for energy

oxygen is consumed, water and carbon dioxide are produced, and energy is captures in ATP

what can be used to make glucose

some amino acids, pyruvate, and glycerol

what CANNOT be used to make glucose

fatty acids