Nutrition Study Guide - Exam 2

What are some of the positive attributes of fat in the diet?

Fat imparts a creamy texture to foods. Many flavors are fat-soluble, so fat enhances the flavor of foods.

chylomicron

Lipoprotein that carries dietary fats (mainly triglycerides) from the small intestine to cells throughout the body. Chylomicrons are first absorbed into the lymphatic system, and then transported via the bloodstream.

VLDL

Lipoprotein that carries triglycerides (and cholesterol) from the liver to cells throughout the body.

large intestine/rectum (protein digestion)

Little dietary protein is present in feces

lacteal

Lymphatic vessel that absorbs fats from the small intestine.

kcals per gram of fat

9 kcals

sterols

A compound containing a multi-ring (steroid) structure and a hydroxyl group (-OH). Cholesterol is a typical example.

lipoprotein

A compound found in the bloodstream containing a core of triglycerides and cholesterol surrounded by a shell of protein and phospholipids.

bile acid

A compound produced by the liver. Bile acids are the main component of bile, which aids in emulsification of fat during digestion in the small intestine

lecithin

A group of phospholipid compounds that are major components of cell membranes.

liver (protein digestion)

Amino acids are absorbed into the hepatic portal vein and transported to the liver. From there, they enter the bloodstream.

branched-chain amino acids

Amino acids with a branching carbon backbone; these are leucine, isoleucine, and valine. All are essential amino acids.

sickle cell disease

An illness that results from a malformation of the red blood cell because of an incorrect structure in part of its hemoglobin protein chains; also called sickle cell anemia.

eicosapentaenoic acid (EPA)

An omega-3 fatty acid with 20 carbons and five carbon-carbon double bonds. It is present in large amounts in fatty fish and is slowly synthesized in the body from alpha-linolenic acid.

docosahexaenoic acid (DHA)

An omega-3 fatty acid with 22 carbons and six carbon-carbon double bonds. It is present in large amounts in fatty fish and is slowly synthesized in the body from alpha-linolenic acid. In the human body, high levels of DHA are found in the retina and brain.

phospholipids

Any of a class of fat-related substances that contain phosphorus, fatty acids, and a nitrogen-containing component. Phospholipids are an essential part of every cell.

Where does lipoprotein lipase break down triglycerides?

Bloodstream

functions of proteins

Building blocks of body components Fluid balance maintenance Acid/base balance (contribute to) Building blocks of hormones and enzymes Immune function Forming glucose Energy yielding (non-preferred source) Contributing to satiety

deoxyribonucleic acid (DNA)

Double strand of nucleic acids that carries hereditary information in cells; DNA directs the synthesis of cell proteins.

conditionally essential amino acids

Nonessential amino acids that cannot be made in adequate amounts to support the body's increased requirements during conditions of rapid growth, disease, or metabolic stress, and therefore become essential (i.e., must be obtained from food).

Why are fatty acids essential?

Omega 3s decrease blood clotting, triglycerides in blood, and inflammation

hydrogenation

The addition of hydrogen to a carbon-carbon double bond, producing a single carbon-carbon bond with two hydrogens attached to each carbon.

amino acids

The building block for proteins containing a central carbon atom with nitrogen and other atoms attached.

limiting amino acid

The essential amino acid in lowest concentration in a food or diet relative to body needs.

Trigylcerides

The major form of lipid in the body and in food. It is composed of three fatty acids attached to glycerol.

transcription

The process by which the code or gene for a protein on a DNA sequence is copied into a single-stranded mRNA molecule that is ready to leave the nucleus.

translation

The process of adding amino acids one at a time to a growing polypeptide chain, according to the instructions on the mRNA.

ribonucleic acid (RNA)

The single-stranded nucleic acid involved in the transcription of genetic information and translation of that information into protein structure.

Why are triglycerides ideal for fat storage?

They are chemically stable. They are energy dense.

Which lipoproteins are made by the liver?

Very-low-density lipoproteins (VLDL)

emulsifier

a compound with both water-soluble and fat-soluble portions that can attract fats and oils into water, combining them.

Identify the genetic variations that increase the risk of cardiovascular disease.

a delay in the removal of cholesterol from the blood

polyunsaturated fat

a fat that has more than one double carbon-to-carbon bond. Nuts, seeds, fish, corn oil, safflower oil, etc.

saturated fatty acid

a fatty acid carrying the maximum possible number of hydrogen atoms (having no points of unsaturation). Saturated fats are found in animal foods like meat, poultry, and full-fat dairy products, and in tropical oils such as palm and coconut. Solid at room temp.

cholesterol

a sterol produced by the liver. Is a critical part of cell membranes and a precursor for the synthesis of vitamin D, bile acids, estrogen, and testosterone. Found only in animal foods but body can make cholestrol.

nonessential amino acids

alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, tyrosine

high quality proteins

animal proteins

LDL

cholesterol. Carries cholesterol made by the liver and from other sources to cells. known as "bad" cholesterol. high level of LDLs is risk factor for cardiovascular disease.

Atherosclerosis

condition in which fatty deposits called plaque build up on the inner walls of the arteries

The fatty acid tails located in the lipid bilayer of the cell membrane are

lined up so they point toward the interior of the membrane fat-soluble

What are the products of fat digestion in the small intestine?

monoglycerides fatty acids

rancidity

occurs when the double bonds in unsaturated fatty acids in food products are broken down by ultraviolet light or oxygen.

Reduced triglycerides, reduced blood clotting, and reduced pain from rheumatoid arthritis are benefits associated with intake of

omega 3 fatty acids

alpha linoleic acid

omega 3 with 18 carbon bonds and three double bonds.

linoleic acid

omega-6 fatty acid with 18 carbon bonds and two double bonds. Good for heart health.

lower quality proteins

plant sources because their amino acid patterns can be different from human proteins

The phosphate heads located in the lipid bilayer of the cell membrane are

water soluble, lined up so they face the watery environments on the inside and outside of the cell

protein denaturation

when proteins are subject to heat, acid or other conditions that disturb their stability; protein uncoils, loses its shape, and loses its function

Functions of Triglycerides

yield energy (9 kcal/gm), storage of energy, insulates and cushions the body, transports fat-soluble vitamins A, D, E, and K. Regulates body processes.

Dietary guidelines for saturated fats of Americans ages 2 and older in total calories

10%

Recommended dietary fat intake

20-35%

phospholipids (longer definition)

Can be produced by the body. Three-carbon glycerol molecule with two fatty acids and a phosphate group on the third carbon. Unlike other lipids, the unique structure allows phospholipids to suspend fat in water. Used in foods such as margarine, chocolate, salad dressings, and frozen desserts to keep the fat dispersed. Found naturally in egg yolks, wheat germ, peanuts, organ meat, and soybeans. Acts as an emulsifier.

Which fat is used to make bile acids?

Cholesterol

HDL

Protein. Contributes to cholesterol removal from cells and, in turn, excretion of it from the body. known as "good" cholesterol. slows development of cardiovascular disease.

small intestine (protein digestion)

Once in the small intestine, the partially digested proteins (and fats) trigger the release of the hormone cholecystokinin (CCK) from the walls of the small intestine. CCK causes the pancreas to release protein splitting enzymes, such as trypsin. FInal digestion of peptides into single amino acids takes place mostly inside cells of the small intestine.

stomach (protein digestion)

Partial protein digested by stomach acid and the enzyme pepsin.

Which of the following are functions of HDL cholesterol in the bloodstream?

Picks up cholesterol from dying cells and other sources,Donates cholesterol to other lipoprotein for transport back to the liver for excretion

Digestion of protein

Protein is denatured by cooking and acid in the stomach. Hormone Gastrin is released into stomach when thinking of food/chewing food. Stimulates the release of acid and pepsin. Pepsin is an enzyme produced by the stomach. It breaks polypeptide into shorter chain of amino acids.

pancreas (protein digestion)

Releases enzymes that will further digest polypeptides in the small intestine.

What does HDL do?

Removes cholesterol from cells and returns to liver for excretion.

Benefits of Omega 3

decrease heart disease decrease arthritis inflammation decrease risk of breast cancer decrease blood cholesterol increase infant intelligence

High-Desnity Lipoproteins *HDLs*

decrease the risk of cardiovascular disease

essential fatty acids

fats needed by the body that must be consumed in the diet because the human body cannot manufacture them

The layer of triglycerides beneath the skin serves to

insulate the body

monounsaturated fatty acids

fatty acid containing one point of unsaturation, found mostly in veggie oils such as olive, canola, and peanut. Liquid at room temp but harden when refrigerated.

unsaturated fatty acid

fatty acid with one or more points of unsaturation. Unsaturated fats are found in foods from both plant and animal sources. Unsaturated fatty acids are further divided into monounsaturated fatty acids and polyunsaturated fatty acids. Liquid at room temp.

What are the products of fat digestion in the small intestine?

fatty acids monoglycerides

essential amino acids

histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine

Pepsin can break a polypeptide chain into

shorter chain of amino acids

What three organs and/or glands produce lipase?

stomach salivary glands pancreas

What are the structural components of a triglyceride?

three attached fatty acids glycerol backbone

What are the major functions of fatty acids and triglycerides in the body?

transport of fat-soluble vitamins energy storage insulation

lipoproteins are important for

transport of fats in the blood and lymphatic system

What does lipase break down in the small intestine?

triglycerides

Which of the following is the body's most efficient form of stored energy?

triglycerides

small intestine breaks down

triglycerides to produce a mixture of fatty acids, glycerol, and monoglycerides

Salivary and gastric lipase digest primarily

triglycerides, butter fat, and short chain fats

3 classes of lipids

triglycerides, phospholipids, sterols