Nutrition Exam Two

Lipids are composed of

Carbon, Hydrogen, Oxygen

3 major categories of lipids

Triglycerides, phospholipids, sterols

Fatty acids

A chain of carbons linked together

What is found on the end of fatty acids

A hydrophilic carboxyl group and a hydrophobic methyl group

Fatty acids are components in

Phospholipids and triglycerides

Short-chain Fatty Acid

Less than or equal to 6 carbons; primarily in dairy (small amounts)

Medium-chain Fatty Acids

8-12 Carbons; found in dairy (small amounts)

Long-chain Fatty Acids

Over 12 carbons; common in meats and seafood

Saturated Fatty Acids

Fatty acid with one or more double bonds

Unsaturated Fatty Acids

Fatty acid with one double bond

Omega-6

Incoporated into cell membranes; precursors to compounds involved in reproduction and blood flow

Omega-3

In cell membranes; help inflammation regulation

Eicosapentaenoic Acid (EPA)

Polyunsaturated fatty acid with a 20-carbon chain and five double bonds; found in fish oils

Docosahexaenoic Acid (DHA)

Polyunsaturated fatty acid with a 22-carbon chain and six double bonds; found in fatty fish

Hydrogenation

Process of adding hydrogens to unsaturated fats

The American Heart Association recommends _ of trans fatty acids per day

2g

Triglyceride Composition

3-carbon back bone with 3 fatty acids

Primary form of lipid found in food and in body

Triglyceride

Triglycerides in the body often ___?

Reflect dietary fatty acids consumed

Phospholipid

Compounds that assist the body in transporting fat through watery substance

Phospholipid Composition

Three-carbon glycerol backbone, two fatty acids bound to first two carbons, third carbon has a bound phosphate group

Phosphate head

Polar and Hydrophilic

Fatty Acid Tail

Nonpolar and Hydrophobic

Phospholipids are an important component of

Cell Membrane and Lipoproteins

Phospholipids function as ___

Emulsifiers

Major components of cell and organelle membranes

Phospholipids and cholesterol

Sterols

Made up of four rings; vital to health and basic metabolic functions

Examples of Sterols

Testosterone, estrogen, Vitamin D

__ makes most of the cholesterol our bodies contain

Liver

Lipid Digestion: Mouth

Lingual lipase digest small amounts of triglycerides but minor digestion occurs here.

Lipid Digestion: Stomach

Most fat is intact here. Gastric lipase digests some triglycerides.

Lipid Digestion: Small Intestine

Bile released from the gallbladder and pancreatic enzymes break lipids into smaller droplets.

Lipid Digestion: Fatty Acids

All three lipids are broken down into their needed components. Other lipids are not digested and absorbed pass through large intestine.

Where is bile stored?

The Gallbladder

In the small intestine, __ emulsifies fats

Bile

Smaller Components of Lipid Absorption

Glycerol and short-chain fatty acids move directly into bloodstream

Micelles

Formed when larger fat components and bile acids combine; helps move into microvilli; diffuse into mucosal cells

__ are the primary source of energy for the heart

Fats

Fat soluble vitamin absorption __ when there is incomplete fat absorption

decreases

Fat supplies __ of ongoing energy during rest

60%

Adipokines

Signaling proteins released by fat tissue that control metabolism, appetite, and inflammation

Resistin

Hormone; promotes inflammation; contributes to insulin resistance; levels increase in obesity

Adiponectin

Horomone; helps reduce inflammation; improves insulin sensitivity; levels decrease in obesity

Leptin

Hormone; Acts on the brain to reduce appetite and regulate long-term energy balance

Eicosanoids

Biologically active; horomone-like; signaling molecules made from 20 carbon fatty acids

Lipoprotein Structure: Outer Shell

Composed of phospholipids and proteins

Lipoprotein Structure: Inner Core

Hydrophobic interior packed with triglycerides, cholesterol, and fat soluble vitamins

Chylomicrons

Formed in intestinal cells to pick up diet-deprived lipids from the small intestine and deliver them throughout the body

Very Low Density Lipoproteins

Lipids made in liver, collected from chylomicron remnants are packaged with proteins and shipped to other parts of the body

Low Density Lipoproteins

Formed after VLDL deposit triglycerides in other tissues; cholesterol rich; deliver cholesterol to other tissues, including blood vessels

High Density Lipoproteins

Made mostly in the liver but also in the small intestine; removes excess cholesterol from cells; return to liver for elimination;

Modifiable Risk Factors of Heart Disease

Smoking, poor diet, overweigh and obses

Non-modifiable Risk Factors of Heart Disease

Diabetes, high blood pressure, high cholesterol

Cardiovascular Disease

Primary type of heart disease linked with fat intake; build up of LDL deposits and immune cells in the arteries;

Low-Calorie Fats

Propylene glycol insertion blocks enzymes that make monoglyceride and 2 fatty acids during digestion

Protein Composition

Carbon, Hydrogen, Oxygen, Nitrogen

11 Non essential Amino Acids

The body can synthesize these on its own using nitrogen and carbohydrate/fat fragments, do not strictly need to be consumed

9 Essential Amino Acids

Human body either cannot make at all, or not in sufficient amounts; must be supplied by the diet

Transamination

Transfer of amine group from one molecule to another to create an amino acid

Conditionally Essential Amino Acids

Nonessential amino acid becomes essential under certain conditions

Amino acids are linked together by __

Peptide bonds

Dipeptides

2 amino acids

Tripeptides

3 amino acids

Polypeptide

More than 3 amino acids

Primary Structure

Amino Acid Sequence: Determined by the sequence of amino acids

Secondary Structure

Polypeptide Shapes: Determined by weak electrical attractions within the polypeptide chain

Tertiary Structure

Polypeptide Tangles: Occurs when polypeptide chain twist and fold into complex shapes

Quaternary Structure

Multiple Polypeptide Interactions: Interactions between two or more polypeptides

Protein Denaturation

Loss of structure when proteins are exposed to heat, acid, or other destabilizing conditions. They uncoil and lose their shapes, lose their ability to function

Protein Digestion in the Stomach

Hydrochloric acid denatures protein strands and activates pepsin from pepsinogen. Pepsin breaks proteins into smaller polypeptides and amino acids.

Protein Digestion in the Small Intestine

Proteases break polypeptides into shorter chains. Peptidases then split most chains into single amino acids for absorption

Protein Absorption

Specific carriers transport amino acids, dipeptides, and tripeptides into intestinal cells. Unused amino acids enter the bloodstream and travel to liver.

Protein Synthesis

Lining up amino acids: tRNA collects amino acids from the cell fluid and takes them to mRNA, each tRNA carries its amino acid to the mRNA.

Correct Amino Acid Sequence

Predictable structure and function

Incorrect Amino Acid Sequence

Structure changes → causes an error in function

Structural Materials of Protein

Building blocks for most body structures.

Most of muscle cells is ______ proteins

Structural; not contractile

Enzymes

Catalysts for chemical reactions

Deficiencies in enzymes

Inborn error in metabolism (inherited)

Horomones

Messengers that help regulate the various systems and functions of the body

Horomones are made of

Lipids or proteins

What is the least efficient function of proteins

Energy production; protein has no major storage form for immediate use

Fluid Balance

Proteins in blood maintain optimal balance between the fluids inside and outside cells and blood vessels

Edema

Swelling due to an excess of fluid in tissues developed when blood albumin is low

Albumin

Most abundant protein in blood; helps protein concentration of blood remain similar to that of cells

Edema is caused by

Excessive protein losses caused by inflammation and critical illness; inadequate protein synthesis caused by liver disease and inadequate dietary intake of protein

Protein Transport

Transport substances across cell walls via pumps

Acid-Base Balance

Body works to maintain pH in a tight range.

Acidosis

Alkalosis

Antigens

Foreign substances that enter our bodies and trigger an immune response

Protein Turnover

Protein synthesis and breakdown

Protein Synthesis

Requires presence of essential amino acids in adequate amounts

Limiting Amino Acid

Missing/present in lowest amount to supply; relative to body’s needs and may result in no function

Protein breakdown

Free amino acids become part of amino acid pool, stripped of nitrogen and used for energy

Deamination

Required to make nonessential amino acids; amino group (nitrogen containing) converted to urea

Where does Deamination occur?

The liver

Nitrogen Balance

Nitrogen consumed vs. nitrogen excreted

Nitrogen Excretion

Amino group (nitrogen containing) converted to urea; excreted in urine; kidneys filter out urea from blood for excretion.

Positive Nitrogen Balance

Intake exceeds excretion, body requires more protein to build new tissues