Uconn Nutrition 1165 Exam #2

Where does energy production from nutrients occur in our cells?

Mitochondria

What pathway produces the most ATP?

Glycolysis (2 ATP) + Citric Acid Cycle (2 ATP) + Electron Transport Chain (28 ATP)

What foods are good sources of unrefined complex carbohydrates? Unrefined simple carbohydrates?

• Good sources of unrefined complex carbs: whole grains, legumes

• Good sources of unrefined simple carbs: milk, fruits, vegetables

What are the differences between refined flour and unrefined flour?

Unrefined flour has bran and germ, while refined grains are made largely from the endosperm and are mostly starch

What is the basic unit of carbohydrate?

Monosaccharides, particularly glucose and fructose

How are bonds between monosaccharides formed? Broken?

• Condensation - links bonds between sugar molecules

• Hydrolysis - breaks bonds between sugar molecules

List three common simple carbohydrates. Where are they found in the diet? Where are they found in the body?

• Glucose - corn syrup

• Galactose - milk

• Fructose - fruit

• absorbed directly into bloodstream following digestion

Why is added sugar considered a source of empty kcalories?

They lack the fiber, vitamins, and minerals found in the original plant. Low nutrient density

List the different types of complex carbohydrates and where they are found in food

• Glycogen- No glycogen in food because lost during slaughter

• Starch- Vegetables (in roots and tubers); Grains (in seeds); Legumes ( beans)

• Dietary fiber- found in fruits/ vegetables. Can be added to foods

How do different complex carbohydrates affect our glycemic response? What nutrition information is used to compare different carbohydrates?

• Raise blood sugar SLOWLY

• Glycemic index - ranking of how a food affects blood glucose compared to a reference value of 100

• Glycemic load - index of glycemic response that occurs after eating specific food

How does fiber affect our cardiovascular health and gastrointestinal health?

Fiber isn't digested by human enzymes. It can help by lowering a person's blood cholesterol, and increase their transit time

What is the main function of glucose in the body?

To provide immediate energy to the cell

When blood sugar drops, how do we increase it to maintain normal levels?

Inject insulin, consume carbohydrates

Describe gluconeogenesis and glycogenolysis (glycogen breakdown)

•Gluconeogenesis is the synthesis of new glucose by the liver from amino acids

• Glycogenolysis is the breakdown of glycogen into glucagon and is released to the liver to initiate glycogenesis

What is glycogen and where is it stored?

• Glycogen is a polysaccharide made of many glucose linked in a highly branched structure

• Stored in muscles and liver in humans

• Storage form carbs in animals

Under what dietary conditions do we increase our glycogen stores?

We increase glycogen stores when we do not need immediate energy

Under what dietary conditions are our glycogen stores depleted/used?

Glycogen stores are used when we are depleted of our energy

Compare the roles of insulin and glucagon in regulating blood glucose.

•Insulin - lowers blood sugar

• Glucagon - raises blood sugar

Where is glucose and insulin made and where do they exert their metabolic actions?

Insulin and glucagon both made in pancreas & preform their work in bloodstream

Describe what happens during the process of glycolysis

Glucose breaks down into 2 molecules of pyruvate.

What is diabetes and what are the long-term complications of this disease?

Diabetes is a disease caused by either insufficient insulin production or decreased sensitivity of cells to insulin. You can have amputations of your limbs, have kidney failure, and become blind.

How do type 1, type 2, and gestational diabetes differ?

• Type 1 is when insulin is no longer made in body

• Type 2 is when insulin is present, but cells don't respond

• Gestational occurs during pregnancy due to hormones

What is lactose intolerance?

The inability to digest lactose because of a reduction in the levels of lactase

What causes lactose intolerance? Who is affected?

• Many people lose the ability to produce lactase

•It affects various people. Many Asian, Native, and African Americans. About 15% Caucasians

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

Triglycerides

What information about dietary fat is included on food labels?

• Calories from fat

• Total fat

• Saturated fat

• Trans fat

How are the different fatty acids categorized?

• Short chain: 4-7 carbons

• Medium chain: 8-12 carbons

• Long chain: >12 carbons

• V. long chain: >22 carbons

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

• Short and medium chain are water soluble and pass directly into the liver

•Long, very long, and cholesterol are water insoluble and must enter lymphatic system to be packaged into lipoproteins so they can enter the liver

List two foods that are sources of monounsaturated fatty acids

olive oil, canola oils

List two foods that are sources of omega-3 fatty acids

flaxseeds, salmon

List two foods that are sources of cholesterol

eggs, butter

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

A saturated fat has no double bonds while monounsaturated fats have one double bond, polyunsaturated fats have two or more double bonds and a trans fat has hyrdogens on opposite sides of the double bond

What type of processing increases the amounts of trans fatty acids?

Hydrogenation increases the amounts of trans fatty acids

Where is trans fat found in our diets? Is it added, naturally present, or both?

Trans fat is both naturally present and added. It is added to cookies, crackers and margarine and is naturally found in milk and beef

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

Bile emulsifies fat (mixed into water as droplets)

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

They must be packaged into a lipoprotein or sent through the lymphatic system

Where do chylomicrons come from and what is their function?

•Chylomicrons are secreted by the intestine

• Their function is to deliver triglycerides to tissues via the lymphatic system

What is VLDL, HDL, and LDL?

• VLDL-assembled by liver; delivers triglycerides to cell

• LDL-assembled by liver; delivers cholesterol to cells

• HDL-made by liver & intestines; pick up excessive cholesterol & bring it back to the liver

List four functions of fat in the body.

Concentrated source of energy, insulation, protection of vital organs, storage of fat soluble vitamins

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

• Immediate source of energy OR stored in adipose tissue

• Fatty acids and glycerol can be used to produce energy in the form of ATP

Beta oxidation of fatty acids in mitochondria beings metabolic pathway 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- triglycerides from adipose tissue are broken down and release fatty acids as an energy source

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

• Non modifiable -genetic background, age and 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 increase blood cholesterol while plant sterols decrease blood cholesterol. Dietary cholesterol is bad but cholesterol is needed in our body

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

• Trans fat and Cholesterol- reduces HDL levels and increases LDL levels

• Saturated fats- increase LDL

What foods are the richest sources of protein?

Foods that come from animal sources

List some plant sources of protein

grains and vegetables

How does protein quality compare between animal and plant sources?

Higher protein in animals

What are amino acids?

The building blocks of proteins

Each contains a central carbon atom bound to a hydrogen atom, an amino group, an acid group and a side chain

Describe the general structure of a protein. How do they differ from other macronutrients?

Amino acids joined together by a peptide bond. Different types of amino acids combine to make different proteins. Unlike other macronutrients they're found in every cell and make up metabolic processes

What is an essential amino acid?

• Cannot be synthesized by the human body in sufficient amounts to meet needs

• Must be included in the diet, if not, new proteins that require them cannot be made unless taken from other body proteins .

What is the "amino acid pool" and where do these amino acids come from?

The amino acid pool refers to all of the amino acids in body tissues and fluids that are available for use by the body

List three structural and/or regulatory functions of proteins in the body.

Fluid balance regulation, acid base balance, energy production

Explain how proteins can provide energy.

i. Deamination - (before being broken down for energy, nitrogen-containing amino group must be removed)

ii. Formation of pyruvate

iii. Formation of acetyl-CoA

iv. Direct entry to TCA cycle and then onto ETC

v. Toxic ammonia used to form urea and excreted in urine

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

• Fatty acids: 1 long hydrocarbon chain, 1 carboxylic acid group

• Triglycerides: 3 fatty acids + 1 glycerol

• Cholesterol: multiple chemical rings