HUN2000 Exam 2

are fats soluble in water?

fats are not soluble in water, thats why they need to emulsify them (phospholipids/bile)

what do fats contribute to?

texture, flavor, and aroma in food

what are the 3 types of lipids found in the body

triglycerides, phospholipids, and sterols

how does a phospholipid structure differ from a triglyceride

has a phosphate group in place of 1 fatty acid

where are phospholipids in the body

cell membrane

what is the most common sterol in the body

cholesterol , precursor to vitamin D and steroid hormones, NOT an essential nutrient for the body

what part of a triglyceride can be made into glucose

glycerol backbone

how are fatty acids classified

length + type and location of the bonds

are these fatty acids liquid or solid at room temp

short chain (4-7C) - liquid at room temp

medium chain (8-12C) - liquid

long chain (12C or more) - solid at room temp

what is saturation

degree to which every possible position on C chain is occupied by H atoms

what are unsaturated points

where H atoms are “missing” and replaced by double bonds between C atoms

what is the end of a fatty acid chain containing a methyl group called

methyl or omega end,

what is the difference between monounsaturated fatty acids and polyunsaturated fatty acids?

monounsaturated fats have one double bond in their carbon chain while polyunsaturated fats have two or more

what are examples of monounsaturated fatty acid oils?

olive, canola, avocado, nuts

what are examples of polyunsaturated fatty acid oils?

corn, safflower, soybean

what is an omega-6

an polyunsaturated fatty acid that has its first double bond at the 6th carbon from the end , has linoleic acid

what is an omega-3

an polyunsaturated fatty acid that has its first double bond at the 3rd carbon from the end, linolenic acid

what oils are omega6 fatty acid found

corn, sunflower, safflower oil

what oils are omega 3 c found

fish oil

what is hydrogenation

process of breaking double bonds in a fatty acid by adding H

what are advantages to hydrogenation

alters texture, protects against oxidation

what are disadvantages to hydrogenation

increases risk of heart disease & cancer, creates trans fatty acid

how is the hydrogen atom around a double bond oriented in a cis-FA and a trans-FA

cis - natural occuring

trans - h atoms on opposite sides, unsaturated bonds converted from cis to trans

what are the essential fatty acids

linoleic acid (omega 6) and linolenic acid (omega 3)

what foods do omega 3/6 come from

omega 3 - salmon, sardines, vegetables, anchovies

omega 6 - flaxseeds, canola, walnuts, corn, sunflower, safflower

which are the omega 3 fatty acids

eicosapentanoic (EPA) and decosahexaenoic (DHA)

where does digestion take place

some in mouth, stomach, mostly in small intestine with pancreatic lipase

what is the function of bile

creates interface between the lipid and watery digestive juices so pancreatic lipase can access the TG and break them down

what are lipid digestion products

glycerol & medium chain FA, both water soluble, monoglycerides, long chain FA, fat soluble

what products can be directly absorbed into the blood stream

glycerol, short and medium chain fatty acids

once inside the intestinal cell how are products of lipid digestion assembled

they are assembled into intestinal cells as micelles

what are micelles

emulsified fat droplets, facilitate fat absorption, composed of fatty acids, monoglycerides, cholestorol, fat soluble vitamins, bile

what transports lipids in the blood from the intestine to tissues/cells

chylomicrons

where are water soluble fats transported to

transported in the blood

where are fat soluble fats transported to

transported through lymphatic system into blood

what are chylomicrons

largest and least dense they contain the most triglycerides, carry lipids from the intestines into the lymph and then the bloodstream. with the help of lipoprotein lipase they deliver fatty acids to body cells

what are VLDLS (very low density lipoprotein)

transport lipids from the liver & with help of lipoprotein lipase deliver fatty acids to body cells

what are LDLs (low density lipoprotein)

are the primary cholesterol delivery system for body cells. LDLs enter body cells by binding to LDL receptors on the cell’s surface

what are HDLs (high density lipoprotein)

smallest and most dense “high density lipoprotein” HDLs carry cholesterol away from cells and return it to the liver

which lipoprotein has the most triglycerides

chlymicrons

which lipoprotein has the most cholesterol

low density lipoprotein (LDL)

what is the densest lipoprotein

HDL (high density lipoprotein)

which lipoprotein takes lipids from the intestinal cell to tissues

chlymicrons

which lipoprotein takes lipids from the liver

VLDL (very low density lipoprotein)

what lipoprotein delivers cholesterol to tissues

LDL (low density lipoproteins)

what lipoprotein picks up cholesterol from tissues.

HDL (high density lipoprotein)

what lipoprotein is considered bad cholesterol

LDL (low density lipoprotein)

what lipoprotein is considered good cholesterol

HDL (high density lipoprotein)

what are ketones?

when there is insufficient carbohydrates, acetyl-CoA can not go through the TCA cycle to produce energy - the liver will convert acetyl - CoA to ketone bodies

when are ketones formed ?

untreated diabetes or very low carbohydrates

what are functions of lipids

energy + storage, stimulate appetite, carry fat soluble vitamins

which nutrients ca be converted into fat

proteins, carbohydrates, fats

what types of fatty acids are associated with cardiovascular disease

trans and saturated fatty acids

does cholesterol or saturated fat intake affect cholesterol levels in the blood

yes both dietary cholesterol and saturated fat intake can influence blood cholesterol levels

are lipids part of a healthy diet? which ones?

monounsaturated and polyunsaturated fats

which factors promote heart disease

saturated fat, trans fat, high blood pressure, diabetes, smoking

which factors prevent heart disease?

diet low in fat with mono- and poly-unsaturated fatty acid, fiber, antioxidants

amino acids consist of a carbon atom bound to what 4 chemical groups?

H atom, amino group, acid group, side chain

how do amino acids differ in structure to carbohydrate and lipids

has a nitrogen element in their structure

what type of bonds hold amino acids together

peptide

why do folds and bends occur in a chain of amino acids?

order of amino acids and their electrical charges

how are the specific sequences of amino acids in a polypeptide chain determined ?

by the sequence of nucleotides in a gene’s DNA

what is transciption? where in the cell does it take place?

the code from the DNA is transcribed into a messenger RNA (mRNA) it occurs in the nucleus

what is translation? where in the cell does it take place?

process in which RNA codons are decoded into amino acids that make up an amino chian (polypeptides), translation occurs on ribosomes

what is genetic mutation? what does it affect?

a change in DNA sequence of a cell, can affect how a cell functions

the different shapes of protein allow them to perform what kind of functions?

carriers, structural, enzymes, parts of organs

what is denaturation of a protein

occurs when protein comes into contact with heat, acid strong base or pshyical agitation, and alters the shape of a protein

amino acids can be used to make

proteins, another aa-not essential, glucose, fat

what is deamination

removal of amino group from amino acids

what are the products of deamination

urea, the carbon backbone (ketoacid) - can be burned for energy, made into glucose, made into fat

what happens to the products of deamination

can be used for energy, made into glucose, or made into fat

what are the effects of too much protein in the diet

more work for liver & kidneys to remove ammonia and then flush it out of the system - requires alot of water

what is an essential AA

AA that cannot be made by your body, must get them from your diet

what is a nonessential AA

AA your body can make on its own, even if you dont get them from food

what is transamination

adding amino group to a fragment of fat, carbohydrate or another AA

what is a limiting amino acid

essential amino acid available in the lowest amount relative to the body’s needs

what happens in the mouth during digestion

nothing, proteins are crushed by teeth

what happens in the stomach during digestion

HCL, denatures protein, activates the enzyme pepsin

what happens in the small intestine during digestion

chemical digestion: enzymes released, bile is released

AA, di-, and tri- peptides transported into the intestinal cell through

mucosal cells

what products of protein digestion are absorbed into circulation

amino acids, dipeptides, tripeptides

what may happen if a food protein is absorbed intact

the immune system may be activated, it will be recognized as a foreign substance by the immune system

what are free radicals? produced by?

molecules with 1 or more unpaired electrons, can come from environment (air pollution, cigarette smoke)

once formed free radicals attack

nearby molecules like DNA , cell membrane, proteins, etc

what are the steps in the free radical chain reaction

(initiation) free radicals initiate chain reaction > (propagation) free radicals make more free radicals > damage membrane lipids, dna, proteins > risk of atherosclerosis & cancer . (termination is where the free radicals are stopped)

what is used to defend against free radicals and oxidative stress

enzymes, dietary antioxidants (vitamin C, E), glutathione

which nutrients can act as antioxidants

vitamin C, vitamin E, beta carotene, selenium, copper, zinc, maganese, iron

how do antioxidants work

neutralizing free radicals by giving up some of their own electrons

which antioxidants protect the water fluids of the body

vitamin c and enzymes with mineral cofactors (copper, zinc, maganese, iron, and selenium)

which antioxidants protect the lipid parts of the body

vitamin e, carotenoids

which work synergistically to inhibit oxidation

vitamin C & E

what minerals are involved as co-factors

iron, magnesium, maganese, cobalt, copper, zinc,

what are phytochemicals

not essential nutrients but have health promoting properties on chronic disease

what are the different phytochemicals discussed in this course

phtoestrogens in soy, falvonoids in blueberries, raspberries, blackberries; alliums in onion, garlic, isothiocyanates in cabbage, broccoli, cauliflower

what are some possible health effects from phytochemicals

antioxidants, heart protective , anti flammatory , estrogen, lowers cholesterol

what are the best sources of phytochemicals

fruits, vegetables, nuts, seeds

molecule that binds some lipids and carries them out with it in feces

fiber

a hormone like molecule made from omega 3 and 6 fatty acids

eicosanoid

triglyceride

3 fatty acids hooked to a glycerol

trans fat

a type of fatty acid produced during hydrogenation