Phy Sci 5 Chapter 4

How are triglycerides broken down and taken into the body?

-After chylomicrons are in the blood circulation, they are taken into cells to be used. -Triglycerides can be taken to adipose tissues, muscles, liver, etc. -Triglycerides found in chylomicrons are released into cells via lipoprotein lipase. -Adipose tissues uptake fatty acids from chylomicrons and repackage it into triglycerides (major storage form) -same process for use in muscle cells

What is a cholesterol ester?

-Animal cholesterol is often consumed in this form. -Have a fatty acid chain attached to the ring structure -Most common dietary cholesterol consumed -Is found in egg yolk, meats, poultry, whole milk, butter -Not essential

What are the uses of cholesterol?

-Found in the plasma membrane and functions in adding fluidity to the cell membrane. -Used to synthesize sex hormones, adrenal hormones, vitamin D -Hormones produced from cholesterol are testosterone, estrogen, progesterone, cortisol, aldosterone. -Used to synthesize bile,

What is the adequate intake of linoleic acid and alpha-linolenic acid?

-Linoleic acid: 14-17g/day for males, 11-12g/day for females -Alpha-linolenic acid: 1.6g/day for males, 1.1g/day for females

What is the difference between monounsaturated and polyunsaturated fatty acids?

-Monounsaturated fatty acids have one carbon-carbon double bond. -Polyunsaturated fatty acids have more than one double bond

How are fatty acids classified?

-Number of carbons in their chain -Level of saturation (the number of hydrogen atoms attached to each carbon) -Both of these affect their storage and metabolism

What is the composition of a triglyceride?

-One glycerol molecule (glycerol is a sugar alcohol) -Three fatty acid molecules (insoluble portion of molecule)

What is the difference between the short chain, medium chain, and long chain?

-Short chain is fewer than 6 carbons -Medium chain is 6-12 carbons -Long chain is more than 12 carbons

What are the two different ways of numbering carbon atoms in triglycerides?

1. Count starting with the carbon of the carboxyl group (termed alpha carbon) 2. Count starting from the last carbon on the opposite end (termed omega carbon)

What are the functions of lipids?

1. Providing energy 2. Hormone synthesis 3. Synthesis of Phospholipids 4. Transport 5. Insulation

What are the functions of adipose tissue?

1. stores triglycerides for energy usage 2. when found subcutaneously under the skin, acts to insulate the body and preserve body temperature 3. forms around visceral organs to hold them in place (e.g. kidneys) 4. forms lipid sheaths (myelin) around the neurons to insulate and to speed electrical signals.

What is the Acceptable Macronutrient Distribution Range (AMDR) for fat?

20% of 35% of total energy. Saturated fatty acids and trans fatty acids should be avoided (consumption is associated with increasesin triglyceride and LDL cholesterol levels in blood). Monounsaturated and polyunsaturated fatty acids should be increased (esp omega-6 and omega-3).

Each gram of lipids provides _____kcals

9

When synthesized in the body, the double bond in a cis fatty acid cannot be placed before the _____ carbon from the omega-carbon.

9th

Once consumed, linoleic acid is metabolized to what?

Archidonic acid, a precursor for many of the eicosanoids

Which is more beneficial to consume? Cis or Trans form fatty acids?

Cis; Trans increases risk of CVD

What are examples of oils with polyunsaturated fatty acids?

Corn oil, safflower oil

What does cortisol do?

Cortisol functions during stress management and nutrient metabolism.

What is the most commonly ingested dietary substance that contains trans fat?

Dairy (minor amounts of trans fat)

What foods are phospholipids found in?

Egg yolk, peanuts, food additives (emulsifiers)

What are the two most common alpha-linolenic (omega-3) acids?

Eicosapentaenoic acid (EPA) abd dicisahexaenoic acid (DHA). Found in tuna and salmon, associated with decreasing CVD risk.

What is the difference between fats and oils?

Fats are lipids that are solid at room temperature. Oils are lipids that are liquid at room temperature.

What are HDLs?

High density lipoproteins. Mainly produced in the liver. HEALTHY. They function to lower LDL concentrations. HDL uptakes the cholesterol stuck in the arteries and returns it back to the liver.

How do food companies add trans fatty acids?

Hydrogenation: this process breaks the double bonds in the monounsaturated and polyunsaturated fatty acids and adds hydrogen atoms, forcing the bulky groups of the double bond on opposite sides. The increased stability and stronger attractive forces of the trans form increase shelf life.

Do chylomicron levels increase or decrease after the consumption of a fatty meal?

Increase. Produced in enterocytes to transport the dietary fat into the lymphatic system and then into the blood circulation.

How does insulin promote lipid storage?

It has an antagonistic effect and promotes the storage of lipids.

What are testosterone's functions in exercise?

It induces muscle growth and its release increases during exercise.

What does estrogen do?

It promotes bone growth and has a protective effect from CVD

How does epinephrine promote lipid storage?

It promotes lipid breakdown and is released from the adrenal medulla during exercise

What does aldosterone do?

It regulates sodium concentration in the blood and therefore has a tremendous effect on regulating blood pressure.

What are the two most common essential fatty acids?

Linoleic acid (omega-6) and alpha-linolenic acid (omega-3).

During rest do we rely more on carbohydrates or lipids for energy?

Lipids

How do lipids functions in transport?

Lipids can be synthesized into lipoproteins such as micelles, chylomicrons, low-density lipoproteins, and high-density lipoproteins. These vesicles carry digested lipids from small intestine or liver to their storage sites (muscle or adipose tissue).

What are LDLs?

Low density lipoproteins. rich in cholesterol and are associated with risk of CVD. BAD. Their cholesterol contents often get stuck in the blood vessels leading to progressive occlusion.

Where are phospholipids found in the body?

Make up the plasma membrane of our cells and are used to transport molecules in the blood. Important in lipid digestion.

What is the structure of a sterol?

Multi-ring structure

Are triglycerides water soluble?

No they are not. They cannot dissolve in water.

Are phospholipids essential?

No. They can be made in our cells.

What are examples of oils with monounsaturated fatty acids?

Olive oil, canola oil, peanut oil

What foods are omega-6 and omega-3 found in?

Omega-6 (linoeleic acid) is found in vegetable and nut oils; omega-3 (alpha linolenic acid) is found in leafy green vegetables, flaxseeds, walnuts, fish

What is the structure of a phospholipid?

One glycerol molecule, two fatty acid molecules, and one phosphate containing group. Part that includes glycerol and the phosphate are water soluble; fatty acid molecules are insoluble.

Define amphipathic.

One part of the molecule is water soluble while one part of the molecule is water insoluble.

What determines if triglycerides are going to be stored in the adipose tissue or in the muscle?

Physical activity

What is a difference between plant and animal sterols?

Plant sterols are not well absorbed in our digestive system; they decrease the absorption of animal sterols.

What are eicosanoids?

The most common product of essential fatty acids synthesized from fatty acids that are 20 carbons in length. They are produced in the majority of body cells as prostaglandins, trhomboxanes, and leukotrines. They function in blood clot prevention, smooth muscle regulation, and immune functions.

How do cis formation fatty acids interact with other molecules?

The shape of the molecule in cis form makes it bend. Therefore, there is less surface area and it does not form many bonds with neighboring molecules. Often found in vegetable oils. Predominant form of double bond is cis.

How do lipids function in the synthesis of phospholipids?

They are used to synthesize phospholipids which are incorporated into the cell membrane. Polyunsaturated fatty acids that are added to the membrane increase its fluidity and flexibility.

Why are omega-6 and omega-3 fatty acids termed essential fatty acids?

They cannot be synthesized in the body.

How do trans formation fatty acids interact with other molecules?

This shape has a high surface area and therefore tends to aggregate more, behaving similarly to saturated fatty acids. It is solid at room temperature.

What is the most common type of lipid that we consume in the diet?

Triglycerides (aka triacylglycerols), usually with long-chain fatty acids

What does trans mean?

Two bulky groups of the molecule are on opposite sides.

What does cis mean?

Two bulky groups of the molecule are on the same side

Which type of fatty acid (unsaturated or saturated) is liquid at room temperature and why?

Unsaturated fatty acids are liquid at room temperature while saturated fatty acids are solid at room temperature. This is because when fatty acid molecules are saturated, they have more surface area and they tend to aggregate together, making them solid at room temperature. When the fatty acid chains are unsaturated, the molecule itself bends. In the bent state, they tend to aggregate less and this makes them liquid.

When does VLDL production increase?

VLDL production increases when consuming a diet that is high in fat and refined sugars. Diets high in unsaturated fats can reduce their production as well as exercise.

What are VLDLs?

Very low-density lipoproteins. They are produced in the liver to carry triglycerides as well as cholesterol to shuttle them to various tissues in the body.

What else do lipoproteins transport other than lipids?

Water insoluble vitamins: ADEK

Are phospholipids water soluble?

Yes they are.

What is the function of Vitamin D?

helps in calcium and phosphorus regulation and strengthens bones

What is the function of Vitamin K?

helps in clot prevention. deficiency leads to anemia

What is the function of Vitamin A?

important for vision, esp night vision

Where is cholesterol produced?

liver, adrenal glands, gonads, small intestine

Animal fat is rich in _________; plant fat is rich in ______________

saturated fatty acids; unsaturated fatty acids

What is the function of Vitamin E?

very important antioxidant that helps in cardiovascular health