Chapter 5 – Lipids- Study Guide answers PDF

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Chapter 5 – Lipids:

What is the predominant form of lipid in our body and food?

Triglycerides are the predominant form of lipids in our foods- they are present in adipose tissue

What information about dietary fat is included on food labels?

Saturated fats and trans fats (total fat)

How do fatty acids, triglycerides, and cholesterol differ in their structure?

Fatty acid- chain of carbon atoms with an acid group Triglyceride- 3 fatty acids attached to a glycerol Cholesterol- only found in humans, does not dissolve in water, multiple chemical rings

How are the different fatty acids categorized?

Saturated fatty acids- carbon chain saturated with hydrogens (no double bonds) Unsaturated fatty acids- carbons NOT saturated with hydrogen Trans fatty acids- created by hydrogenation- causes double bonds to become saturated, raise blood cholesterol levels and increase the risk for heart disease

How does fatty acid chain length affect their physical properties, absorption, and transport throughout the body?

SMALL- liquid at room temp (milk) MEDIUM-liquid at room temp (coconut oil)- WATER SOLUBLE

LARGE-solid at room temperature (beef fat) WATER INSOLUBLE Very LARGE- (butter) WATER INSOLUBLE

List two foods that are sources of monounsaturated fatty acids, two that are sources of omega-3 fatty acids, and two that that are sources of cholesterol.

Monounsaturated fatty acids- olive oils, nut oils Omega 3- spinach, salad and vegetable oils Cholesterol- eggs, butter, bacon

What distinguishes a saturated fat from a monounsaturated fat? From a polyunsaturated fat? From a trans fat?

Saturated fats have no double bonds while monounsaturated fats have one double bond Monounsaturated fats have one double bond Polyunsaturated fat have 2 or more double bonds Trans fats have hydrogen’s on either sides of the double bonds

What type of processing increases the amounts of trans fatty acids? Where is trans fat found in our diets? Is it added, naturally present, or both? What would you look for on the ingredients label to identify if a food contains trans fats?

Hydrogenation- increases the amounts of trans fatty acids Trans fat is found naturally and can be added Less than .5 g per serving it says 0% trans fat Trans fat increases blood LDL and decreases blood HDL

What is the function of bile in fat digestion and absorption?

Bile emulsifies fat- it is created in the liver and stored in the gallbladder

Bile becomes active when it reaches the small intestine where fat is broken down

How are fat-soluble nutrients absorbed and transported throughout the body?

Must be packages into a lipoprotein. Sent through lymphatic system

Where do chylomicrons come from and what is their function? What about VLDL, HDL, and LDL?

Chylomicrons are secreted by the intestine Chylomicrons deliver tryglycerifes to tissues via lymph system

List four functions of fat in the body.

How is fat broken down for energy in our body? What metabolic processes are involved?

Pancreatic lipase is released into the small intestine to break down tryglycerides into fatty acids, monoglycerides and glycerol Micells- allow VLC and LC acids to get close enough to the microvilli so that lipids can diffuse into the mucosal cells/ Once they are diffused through , monoglycerides are reassembled into triglycerides and enter the lymphatic system Beta oxidation in mitochondria breaks down fatty acids to produce ATP

During fasting/feasting conditions, what happens to fat in our body? Is it stored or broken down for energy? What enzymes are important for this?

FEASTING- excess energy is stored as triglycerides in adipose tissue FASTING- tyclerides from adipose tissue are broken down and release

What are the risk factors for heart disease? Which ones are not modifiable? Which ones are modifiable?

Dietary, cholesterol, saturated fat, trans fat, sodium, excess sugar, excess energy Non modifiable- genetic background, age, gender Modifiable- high bp, obesity, blood lipid levels, smoking, activity and diet

What is the difference between cholesterol and plant sterols? Where are they found in foods? How do they affect our blood cholesterol?

Cholesterol is found in animals and increases blood cholesterol while plant sterol decrease blood cholesterol. Dietary cholesterol is bad, however it is needed for our body

How do HDLs differ from LDLs?

HDL brings cholesterol from cells back to liver to get rid of it while LDL brings cholesterol to cells

How are blood levels of LDLs and HDLs related to the risk of cardiovascular disease?

High HDL reduces risk while high LDL increases risk

How do the different fatty acids/fats affect our heart disease risk? How do they affect our LDL and HDL levels?

Trans fat/ cholesterol- reduce HDL levels and increase LDL levels Saturated fats – increase LDL...