Lecture 18

proteins

proteins

cannot be stored in the human body

proteins

Because they cannot be stored in the body, they must be consumed daily

0.8 g

What is the current recommended daily intake of protein per kg of body weight for adults?

twice

the protein intake in the U.S is __________ what is necessary

greater than 0.8 g

children need how many g of protein per kg of body weight given that their bodies are growing and synthesizing protein

High protein foods

meats, fish, tofu, beans, nuts, seeds, eggs, milk, and dairy

20

How many amino acids naturally occur in proteins?

10

Humans can synthesize how many out of the 20 amino acids needed for proteins?

essential amino acids

What are the 10 amino acids humans cannot synthesize called?

Diets that include animal products

supply all needed amino acids

plants

do not have all amino acids but differ in the composition of amino acids

all needed amino acids

a combination of plant-based proteins provides..

Denaturation

the process of altering the shape of a protein w/ out breaking the amide bonds that form the primary structure

secondary, tertiary, and quaternary

denaturation disrupts which protein structures?

primary

Which protein structure does denaturation not disrupt?

high temp, acidic, or basic environments

can cause protein denaturation

protein hydrolysis

involves breaking the peptide bonds

mouth

breakdown of proteins starts in the..

acidity of stomach juices

causes digested proteins to denature during digestion

the enzyme pepsin

present in the stomach gastric juices, cleaves some of the peptide bonds of large proteins to make smaller peptide chains

sodium bicarbonate

As chyme enters duodenum, pancreatic duct cells release juices rich in..

sodium bicarbonate

neutralizes low pH of the chyme during digestion

trypsin and chymotrypsin

What enzyme do pancreatic acinar cells release into the pancreatic juices that start to break down proteins?

facilitated diffusion

In the small intestine, amino acids are transferred into enterocytes into the blood by what process?

the body's amino acid pool

Once the amino acids are in the blood, they are transported to liver where they become part of what?

amino acid pool

supplies cells in the body w/ amino acids

protein synthesis

all cells in the body use amino acids for..

they are catabolized for energy

What happens to excess amino acids that cannot be stored in the body?

Diabetic Ketoacidosis (DKA)

a life threatening complication of diabetes most common among people w/ type 1 diabetes although people w/ type 2 diabetes can also develop this

when there's a complete absence of insulin

When does DKA develop?

insulin

Glucose cannot enter cells without..

it starts to break down fatty acids to form Acetyl CoA

Because glucose cannot enter cells w/ out insulin, liver does what to compensate?

ketone bodies

From Acetyl CoA liver starts to make?

into the blood

Where do ketones move once synthesized?

ketones

are water soluble and as such are soluble in blood

ketosis

accumulation of ketones in the blood

Tissue cells

can uptake ketones from blood

re-converted back into acetyl CoA and metabolized for energy

Once inside tissue cells, ketones can be..

more acidic

Since ketones are acidic molecules, an increase of ketones can cause the blood to be..

excess ketone

are excreted out of body in urine

ketoacidosis

an abnormally high concentration of ketone bodies can lead to..

ketoacidosis

a life-threatening condition causing blood to become acidic

cholestero

a nonhydrolyzable lipid

Cholesterol

obtained from the diet and synthesized by liver

sterols

cholesterol belongs to a group of nonhydrolyzable lipids called..

300 mg

The American Heart Association recommends that daily intake of cholesterol should be less than..

400-500 mg each day

Average American diet with cholesterol includes?

dietary cholesterol

is not broken down in the digestive tract and travels to small intestine undigested

in enterocytes

WHere does cholesterol combine w/ fatty acids to form cholesteryl esters that along w/ triacylglycerols and apolipoproteins form chylomicrons ?

chylomicrons

from enterocytes, these enter the lymph system and are ultimately released into the blood

Chylomicrons

deliver triaglycerols to the cells

cells

uptake triacylglycerols for further breakdown

Chylomicron remnant

if contains cholesterol it is transported into the liver