ANSC314 Exam 2 Material

Naming unsaturated fatty acids: count the ______ until you hit a double bond to find the omega number

carbons

________ and ________ acids are both essential fatty acids that must be obtained from diet

- linoleic

- linolenic

Melting point of fatty acids are determined by _____________ and _______________

- length of carbon chain

- degree of unsaturation (#C=C)

An increasing carbon chain length ________ melting point

increases

Fatty acids less than 10 carbons are _________ at room temperature

liquid (oils)

Fatty acids more than 10 carbons are __________ at room temperature

solid (fats)

The longer the fatty acid the more likely or unlikely they are solids at room temperature?

likely

The shorter the fatty acid the more likely or unlikely they are liquid at room temperature?

likely

More double bonds in a fatty acid means

the higher probability they are liquids

Increased double bonds in a fatty acid ________ melting point

decreases (more liquidy)

Composition of __________ fatty acid determines physical nature

triacylglycerol

High proportion of short chain and unsaturated fatty acids have low ________

melting point

Elongation

adding double bonds

Soft fats in plants, marine oils (fish)

- linoleic

- linolenic

- oleic

Firm/hard fat in mammals

- palmitic

- stearic acids

Unsaturated, soft fatty acids in mammals

subcutaneous fat

Saturated, firm/harder fatty acids in mammals

deep body fat (kidney)

In ________, fat depots are more saturated and firmer

ruminants

Fat depots are ____________________, converting unsaturated fatty acids into saturated fatty acids

hydrogenated in rumen

In ______________, tissue fat resembles fats in diet

monogastrics

In _____________, there are longer chains of fatty acids and PUFA (liquid/soft)

marine fishes

This species has 18,000kg of spermaceti oil in head (mix of triacylglyercols and waxes with lots of unsaturated fatty acids)

sperm whale

Buoyancy of the sperm whale changes to match the _______ of the sea water while feeding, by the lipids __________ at lower temps

- density

- crystallizing

There is an enzyme in mammals where it can add a double bond from carbon 1 to carbon 9, thus creating linoleic and linolenic acids

false

Which enzyme removes two hydrogen atoms from a fatty acid. creating a carbon/carbon double bond?

desaturase

____________ is used to synthesize oleic acid, ubiquitous component of all cells in the human body

△9 desaturase

Which acids can be synthesized from linoleic acid?

- arachidonic acid

- y-Linoleic acid

Can cats convert linoleic acid to arachidonic acid?

No

Activity of ______________ and ______________ are rate-limiting for synthesis of EPA and DHA for humans

△-6 desaturase, △-5 desaturase

Poly-unsaturated fatty acids are divided into 3 classes

- linoleic family (w-6)

- linolenic family (w-3)

- oleic family (w-9)

Linoleic family functions

- growth

- fertility

- maintaining skin and RBC structure

Linolenic family function

- structure and function of eye

- structure and function of central nervous system

Metabolic roles of essential PUFAs (polyunsaturated fatty acids)

- phospholipid structural components

- fat transport

- cholesterol transport

- precursor of eicosanoids

Eicosanoids include...

- prostaglandins (blood pressure and clotting)

- thromboxanes (platelet aggregation)

- prostacyclins (oppose actions of thromboxanes)

Conjugated linoleic acid are ______ trans-fats

good

CLA is high in _______ and _________

ruminant meat, milk

What is the hydrogenation of fatty acids?

the conversion of unsaturated to saturated fatty acids

In hydrogenation of fatty acids, ___________ carry a slightly _________ charge, readily accept positively charged H+ atoms

double bonds, negative

By forcing H2 through unsaturated fatty acids until the desired consistency is produced leaves saturated fats and ________________ (not healthy) many of which are in the ________ form

partially hydrogenated fats, trans

Trans-fats are a ________ of hydrogenation of oils

byproduct

Which acid is the principle trans unsaturated fatty acid often found in partially hydrogenated vegetable oils?

elaidic acid

Peroxidation of unsaturated fatty acids

anti-oxidants reduce peroxidation by acceptance of free radicals

fats can get _______

rancid

What is the basic unit for all sterols?

sterol esters

Sterols in nature

- phytosterols

- mycostvitaminerols

- zoosterols

Cholesterol (zoosterol)

- synthesized in body from acetate units

- precursor of steroids, bile acids and vitamins

- main constituent of brain tissue

- 35g in human body

True or false: Dietary cholesterol is no longer considered to be a major risk factor for coronary heart disease

true

Fatty acids of waxes tend to be ________ or have one double bond

saturated

Waxes

non glycerol based lipids

Where can waxes be found?

- animal tissue

- plant tissue

- microbial tissue

Functions of waxes

- energy stores

- waterproofing/protection of plant external surfaces

Tocopherols

fat-soluble alcohols with antioxidant properties

True or false: tocopherols are important in the stabilization of cell membranes

true

Free fatty acids

non-esterfied fatty acids

Free-fatty acids are a ________ constituent of animal and plant tissues

minor

Compound lipids

- glycolipids

- lipoproteins

- phospholipids

Glycolipids

CHO + fat (fat in plants)

Lipoproteins

fat + protein (transports fat in body)

Phospholipids

PO4 + fat (component in cell membranes)

What are the most important type of lipid?

simple lipids (fats and oils)

Lecithin

white waxy solids

Lecithin is...

- a phospholipid

- most abundant phospholipid of cell membranes: surfactant in lungs

- Secreted in bile (emulsified fats/lipids)

- Body store of choline, an important methyl donor

Glycocholic acid

- bile in duodenum

- role is emulsification of fats and activates lipase

Prostaglandin F2A

- estrous synchronization

- synthesis from cholesterol

First step of hydrolysis and absorption

Short chain fatty acids, acetic, propionic, butyric etc. are absorbed directly into the blood from the rumen, cecum and large intestine.

Second step of hydrolysis and absorption

Dietary triglycerides must be broken down physically and held in suspension - emulsification.

Third step of hydrolysis and absorption

Enzymatically digested by lipase within the small intestine

Fourth step of hydrolysis and absorption

After lipase action, monoglycerides and free fatty acids retain their association with bile acids and complex with other lipids to form structures called micelles.- small aggregates that move around in the small intestine

Fifth step of hydrolysis and absorption

Micelles are essentially small aggregates (4-8 nm in diameter) of mixed lipids and bile acids suspended within the food contents.

Sixth step of hydrolysis and absorption

As the food contents are mixed, micelles bump into the brush border of small intestinal enterocytes, and the lipids, including monoglyceride and fatty acids, are taken up into the epithelial cells.

In the enterocyte, fatty acids and monoglyceride are transported into the _______________________________, where they are used to synthesize triglyceride

endoplasmic reticulum (inside the cell)

In the Golgi, triglyceride is packaged with cholesterol, lipoproteins and other lipids into particles called _________________ (major lipoprotein)

chylomicrons

_____________ are the most important transport molecules

lipoproteins

______________ are lipoproteins containing varying amounts of lipids and proteins.

Chylomicrons

Lipoprotein

inferior of triglyceride and cholesterol, surrounded by phospholipids and proteins

Function of lipoprotein

transport all hydrophobic fat molecules

Chylomicron

- very low density lipoprotein

- the biggest lipoprotein

Chylomicrons carry ___________ from the intestines to the liver, skeletal muscle, and adipose tissue

triglycerides

Very low density lipoproteins (VLDL) carry _______________ from the liver to adipose tissue

newly synthesized triglycerides

LDL

'bad' cholesterol

High LDL is associated with

atherosclerosis

HDL

"good" cholesterol

HDL helps clear blood of ______

LDL

Chylomicron transports...

- triglycerides

- cholesterol

- phospholipids

Chylomicron helps to release _______ in blood to adipose and muscle

lipids

HDL returns to _______

liver

Chylomicron + ______ --> VLDL in liver

HDL

Where does oxidative catabolism (fatty acid degradation) occur?

mitochondria

Where does fatty acid synthesis occur?

cytosol

Tissues involved in fatty acid synthesis

- adipose and mammary gland (ruminants)

- liver (humans, birds)

- liver and adipose (rodent, rabbits)

High blood fatty acids (NEFA, TG) are a strong indicator of ____________

heart disease

Is blood lipid concentration the same as dietary concentration?

No

What is the diet-heart hypothesis?

- trans fat decreased HDL

- omega 3 increased HDL

- sugar or starch increase triglycerides

What are the fatty acid requirements?

- omega 3

- omega 6

- arachidonic

- EPA

- DHA

What are some fatty acids to minimize in diet?

- trans fatty acids: decreases HDL-cholesterol, hardens arteries

- heated polyunsaturated fats: form carcinogenic compounds and trans fats

- saturated fat: some research suggests it increases LDL-cholesterol

______% of blood cholesterol is made in the body

75-80

Cats and dogs diet

carnivores evolved on high fat, high protein diets, but most pets consume grain-based diets

Horse diet

high forage adequate for substantial exercise

Cattle diet

- high forage: slower growth and fattening

- high concentrate (grain finished): faster fattening

Composition of average protein

- carbon (51-55%)

- hydrogen (6-7%)

- oxygen (22-24%)

- nitrogen (16-18%)