Chapter 5-Proteins

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Nutrition

Proteins are also called

peptides

proteins

nitro-containing macronutrients made from amino acids and joined together by peptide bonds

Peptide bond

a chemical bond that joins amino acids

protein size is

variable

protein size depends on the

number of amino aicds

Most proteins have how many amino acids

250 to 300

dipeptides have

two amino acids

tripeptides have

three amino acids

2-12 amino acids are called

oligopeptides

polypeptides

12 amino acids

Parts to a protein

central carbon atom bonded to a hydrogen atom, amino group, carboxlyic group, and R-group

amino group

-NH2. Central carbon boned to an amino group, carboxylic acid group, and R-group

carboxlyic acid goup

COOH

R group

part of amino acid strucutre that distinguishes it from other amino acids

What causes protein to bend and take on unique and complex shapes

the three charged components-amino group carboxylic acid group, and the R group

Body needs how many amino acids to make all the protein it requires?

20

types of amino acids

essential, nonessential, and conditionally essential

essential amino acids

consume through diet because the body can't make them

α-keto acid

compound that accepts an amino group from an amino acid in the process of transamination

transamination

process where an amino group is formed via the transfer of an amino group from one amino acid to α-keto acid

PKU

body canot convert phenylaline into tyrosine. Cause nonessential amino acids to become conditionally essential

Foods with the same amount of protein may differ in

combination of amino acids

Food proteins can be categorized based on the balance of

amino acids they have

complete protein sources

those that contain adequate amounts of essential amino acids

Incomplete protein source

a food that lacks or contains very low amounts of one or more essential amino acids

limiting amino acid

the essential amino acid in the lowest concentration in an incomplete protein source

Protein complementation

combining incomplete protein sources to provide all of the essential amino acids in relatively adequate amounts

High-quality protein

a complete protein source with high amino acid bioavailability

low-quality protein

a food that is either an incomplete protein source or one that has low amino acid bioavailability

GMO

organism made by genetic engineering

Steps in protein synthesis

cell signaling, transcription and translation

Cell signaling

cell receives a signal to produce a protein.

Turning on of protein synthesis by cell signaling is called

up-regulation

turn of of protein synthesis by cell signaling is called

down-regulation

up-regulation

increased expression of a gene

down-regulation

decreased expression of a gene

up and down regulation regulate

the body's ability to produce only the proteins it needs and to stop when needed

Transcription definition

mRNA is made using DNA as a template

Chromosomes

a strand of DNA and associated proteins in a cell's nucleus

Each chromosome is subdivided into thousands of units called

genes

Genes

portion of chromosome that codes for the primary structure of protein and has instructions to make peptides

mRNA

a form of RNA involved in gene transcription

Translation definition

process whereby amino acids are linked together via peptide bonds on ribosomes using mRNA and tRNA

Translation process

mRNA leaves the nucles and binds to ribosomes in the cytoplasm. tRNA translates the info carried by the mRNA by delivering amino acids in the correct sequence to the ribosome, resulting in the production of a polypeptide strand.

ribosome

organelle that is associated with the endoplasmic reticulum in the cytoplasm, involved in gene translation

tRNA

a form of RNA in the cytoplasm involved in gene translation

Proteins get their shape by

folding and combing with other peptide chains or substances

Primary structure

single peptide chain that is determined by DNA code

The primary structure and it s effect on the protein

determines protein's basic chemical and physical characteristics. It's the basic identity

Sickle cell anemia

a disease in which a small change in he amino acid sequence of hemoglobin causes red blood cells to become misshapen and decreases the ability of the blood to carry oxygen and carbon dioxide

SECONDARY STRUCTURE

folding of a protein because of weak bonds that from between elements of the amino acid backbone

α-helix

spiral stair case (2ndary)

β-folded sheet

2ndary-folded paper fan

Tertiary structure

folding of a polypeptide chain because of interactions among the r-groups of the amino acids (3d structure)

Quaternary structure

combining of peptide chains with other peptides chains in a protein t

to function properly, some proteins have precisely positioned nonprotein components called

prosthetic groups

prosthetic groups

nonprotein component of a protein that is part of the quaternary structure

what determines protein shape?

primary, secondary, tertiary, and quaternary structure

shape determines

function

Denaturation

alteration of a protein's three dimensional structure by heat, acid, chemicals, enzymes or agitation

Denaturation occurs when

a protein unfolds

what is affected by denaturation

secondary, tertiary, quaternary

Denaturing agents

compounds and conditions that cause denaturation

examples of denaturation

physical movement, heat, detergents, acids, bases, salts, alcohol, and heavy metals (lead and mercury)

Genetic makeup

particular DNA contained in a person's cells

Mutation

the alteration of a gene

Some mutations are

good and bad

Polymorphism

an mutation in a gene that is present in at least 15 of the population

Mutation-how does it affect health?

Impacts it

Epigenetics

alterations in gene expression that don't involve changes in the DNA sequence

Epigenetic modifications are responsible for

diverse gene expressions

epignetic influence on chronic ****

developing chronic diseases

Human Genome Project-aim of study

study of nutrigenomics

Nutrigenomic perspective-what is their goal in terms of nutrition?

Developing a precise dietary plan specific to someone's DNA and genetic make up

Nutrigenomics

science of how genetics and nutrition together influence health

Protein digestion begins

when it enters the stomach

Step 1 of protein digestion

gastric cells release gastrin which enters the blood causing the release of gastric juices

Gastrin

hormone secreted by endocrine cells in the stomach, which stimulates the release of gastric juices

Step 3 of protein digestion

partially digested proteins enter the small intestine and cause the release of hormones secretin and CCK

Step 2 of protein digestion

hydrochloric acid in gastric justice denatures proteins and converts pepsinogen to pepsin, which begins to digestion proteins by hydrolyzing peptide bonds

pepsinogen

the inactive form of pepsin, produced in the stomach

Step 4 of protein digestion

secretin stimules the pancreases to release bicarbonate into the intestine. Bicarbonate neutralizes chyme. CCK stimulates the pancreas to release proenzymes into the small intestine

proenzyme

inactive precursor of any enzyme

pepsin

enzyme needed for protein digestion

protease

enzyme that cleaves peptide bonds

step 5 protein digestion

pancreatic enzymes are converted to active enzymes in the small intestine. These enzymes digest polypeptides into tripeptides, dipeptides, and free amino acids

step 6 protein digestion

intestinal enzymes in the lumen of the small intestine and within the mucosal cells complete protein digestion

trypsinogen, chymotrypsinogen, proelastase, poricarbixtoeotidase

inactive proenzymes produced in the pancreas and released into the small intestine in response to CCK

trypsinogen, chymotrypsinogen, proelastase, poricarbixtoeotidase converted to what in the small intestine

trypsin, chymotrypsin, elastase, carboxypeptidase

trypsin, chymotrypsin, elastase, carboxypeptidase

active enzymes involve din protein digestion in the small intestine

food allergy

a condition in which the body's imune system reacts against a protein in food

Food intolerance

a condition in which the body reacts negatively toa food or food component but doesn't mount an immune response

anaphylaxis

a severe and potentially life threatening allergic reaction

effects of anaphylaxis

imune response-drop in blood pressure, rapid pulse, dizziness, narrowing airways

Protein and its involvement in structure

cell membranes, organelles, muscles, skin, bones, hair and fingernails

an enzyme is a

catalyst

catalyst

increase rate of reaction without being consumed

Protein-movement

protein fascinates movement

Proteins major involvement with the body

structure, catalyzing,movement, transportation, fluid balance, pH balance, energy source(glucose and energy), communication devices

protein transportation

transport proteins which escort substances into and around the body and the cell membrane

examples of transport proteins

hemoglobin-transports gases like o2 and CO2 and binding proteins that carry hromones and fat-soluble vitamins in the blood

protein in communication

proteins and hormones make up the body's communication network

protein in protecting the body

skin protecting the inner parts, blood clots from proteins closing off wounds, antibodies fight of disease

antibodies

protein produced by the immune system that helps fight infection

Fluid balance-protein

how fluids are distributed in the body and balances between intracellular space and extracellular space and between intravascular fluid and intestinal space

albumin

protein in blood that regulates fluid between intravascular and intestinal spaces

Edema

buildup of fluid in the interstitial space-swelling in the body

Protein regulate PH

regulate base and acid

Protein for energy

use amino acids for glucose synthesis(maintain glucose levels), store excess energy when protein intake is more than adequate, and ATP production

When does the body look for protein as an alternate source of glucose

when ATP and glycogen are low

To convert amino acids to glucose

muscle tissue is broken down and th eliver takes up the amino acids

Gluconeogensis the

process whereby glucose-yielding amino acids called glucogenic amino acids are converted to glucose

Glucogenic amino acids

amino acid that ca be converted to glucose via gluconeogensis

Gluconeogensis

synthesis of glucose from nocarbonhydrate sources

Deamination

removal of an amino group from an amino acid

Gluconeogensis-the process needs what before amino acids can be converted glucose or used as a source of energy

deamination

eating extra protein during times of glucose and energy sufficiency

fat storage

Protein turnover

the cycle of protein synthesis and protein degradation in the body, which is regulated by hormones

proteins-do they get used up again?

yes

Labile amino acid pool

Amino acids that are immediately available to cells for protein synthesis and other purposes

what contributes to the amino acid pool

amino acids from protein degradation (proteolysis) and dietary amino acids

New proteins are produced from

recycled and newly obtained amino acids

Deanimation produced what

ammonia NH3-toxic to cells

in response to ammonia production, the liver

converts ammonia to urea-less toxic substance

urea

nontoxic nitrogen containing compound that is produced from ammonia

Nitrogen balance

protein intake is equal to protein loss by the body

Negative nitrogen balance

protein intake is less than protein intake loss by the body

positive nitrogen balance

protein intake is greater than protein loss by the body

nitrogen balance-why does it matter

helps clinicians diagnose and treat certain diseases and physiological conditions

why eat protein

amino acids and additional nitrogen to make nonessential amino acids and other nonprotein, nitrogen-containing compounds such as DNA

When should we eat lots of protein

prego, recovering from trauma like burns or illness

UL for protein

NO UL because people who are healthy and eat lots of protein show little harmful effects

Athletes-protein

debate-some says they need more some say they don't

AMDR protein

10 to 35%

vegetarian

those who don't consume any or selected foods and beverages made from animal products (no dairy and no meat)

lacto-ovo vegetarian

type of vegetarian who consumes diary products and eggs

lactovegetarian

vegetarian that consumes dairy products but no eggs

vegas

avoid all animal diets

vegans deficient in

calcium, zinc, iron, vitamin b12

vegetarians deficient in

protein, iron, calcium, zinc, and vitamin b12

vegetarians and diary products

watch saturated fat and cholesterol

protein energy malnutrition

protein deficiency accompanied by inadequate intake of protein and often of other essential nutrients as well

Protein deficiency in places where

amount and variety of food is scarse. Children mostly affected because they need high protein amounts

Marasmus

PEM form characterized by extreme wasting of muscle and adipose tissue

Kwashiorkor

PEM form characterized by edema in the hands and feet

ascites

abnormal accumulation of fluid in the abdominal activity

children with kwashiorkor

cracked, peeling skin, enlarged fatty livers, and unnaturally blond or red hair

Adults and PEM

most have Marasmus-low muslce, fatty liver, edma

high protein consumption

don't have bad health outcomes if lean meats are considered (watch high satured fat and cholesterol)

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