nutrition exam 2

The lipid family includes…

triglycerides, sterols, and phospholipids

What makes up a triglyceride?

1 glycerol and 3 fatty acidssaturated (like butter) are solid at room temp; unsaturated (vegetable oils) are liquid at room temp

Structure and function differences between saturated fatty acids and unsaturated fatty acids

saturated (like butter) are solid at room temp; unsaturated (vegetable oils) are liquid at room temp. Saturated fatty acids have no double bonds in their hydrocarbon chains, while unsaturated fatty acids contain one or more double bonds.

Name some characteristics of a phospholipid

Phospholipids have a hydrophilic head and two hydrophobic tails, forming a bilayer in cell membranes. They are critical for membrane structure and fluidity.

Digestion of lipids – key excretions in digestion

The key excretions in lipid digestion are the final breakdown products, free fatty acids and monoglycerides, which are formed by lipase enzymes in the small intestine with the help of bile salts. After being absorbed into intestinal cells, these products are reassembled into triglycerides, packaged into chylomicrons, and enter the lymphatic system, eventually reaching the bloodstream. Unabsorbed fats and other components like cholesterol and bile salts are eventually eliminated in the feces.  

Know the 4 types of lipid transport and be able to give an example for each (chylomicrons, VLDL, LDL and HDL)

chylomicrons- Contain the highest amount of triglyceride and are therefore the least dense, they carry nutrients from food to bloodstream and and lymph system to be delivered to tissues VLDL- transports triglycerides from the liver to other tissues LDL-carries “bad” cholesterol through blood and can contribute to plaque buildup on arteries. HDL- carries “good” cholesterol to liver for excretion

Cholesterol sources in the diet -- which type of foods contain cholesterol?

meat, eggs, seafood, poultry and dairy products (animal products)

What are the recommendations to include dates in your diet?

eat 2-3 per day as a natural sweetener and energy source, or use them in recipes like smoothies, energy balls, or as a substitute for sugar in desserts.

What is the role of fat in the body?

Fat serves as the body's primary form of energy storage, cushioning vital organs and insulating against extreme temperatures. Beyond these functions, fat is a dynamic endocrine organ that secretes hormones crucial for regulating metabolism and appetite. It also aids in the absorption of fat-soluble vitamins (A, D, E, and K) and is a key structural component of cells and nerve tissues.

what happens when deficient in a fatty acid

A deficiency in fatty acids can lead to widespread issues, most commonly manifesting as dry, scaly skin, hair and nail problems, fatigue, brain fog, joint pain, and a weakened immune system. 

What differentiates one amino acid from another?

the R group

What is an essential amino acid and non-essential amino acid?

an essential amino acid is one that we must obtain from our diet and a non essential amino acid is one that our body makes in its own

Key terms: denaturation and deamination?

denaturation: change in a proteins shape; loses function; happens from heat, agitation, an acid or base deamination: Removal of nitrogen as part of the breakdown of an amino acid

What is nitrogen balance? Give examples of positive nitrogen balance, negative nitrogen balance and nitrogen equilibrium.

positive:Growing children and adolescents: Rapid growth requires a surplus of nitrogen to build new tissues and muscle. negative: Malnourished individuals: People who do not consume enough protein will eventually begin breaking down their body's protein stores for energy. equalibrium: healthy adult that comsume a proper amount of protein

What is the RDA for protein in healthy adults? Be able to calculate protein needs of a healthy adult.

0.8g/kg per day; based on healthy body weight; covert pounds to kg (divide by 2.2) then multiply by 0.8

What are the roles/functions of proteins?

remodel and build proteins

What is the digestibility of animal proteins and plant proteins? Which is higher?

Animal protein has higher digestibility (90–99%) compared to plant protein (70–90%),

Protein digestion: Stomach and small intestines

stomach:partial breakdown (hydrolysis) of proteins. Hydrochloric acid uncoils (denatures) each protein’s tangled strands so that digestive enzymes can attack the individual peptide bonds. The hydrochloric acid also converts the inactive form of the enzyme pepsinogen to its active form, pepsin Pepsin cleaves proteins into small polypeptides and amino acids. small intestine: When polypeptides enter the small intestine, several pancreatic and intestinal proteases hydrolyze them further into short peptide chains, tripeptides, dipeptides, and amino acids. Then peptidase enzymes on the membrane surfaces of the intestinal cells split most of the dipeptides and tripeptides into single amino acids. Only a few peptides escape digestion and enter the blood intact.

What are some health effects of excess protein intake?

What is a catabolic and anabolic reaction?

catabolic: large molecules broken down to smaller ones; release energy; ex: triglycerides to fatty acids, hydrolysis reaction breaking down glycogen to glucose anabolic:Small molecules are put together to build larger ones; require energy; ex: Glucose molecules joined together to make glycogen chains,

What are the four steps of converting a macronutrient into energy?

glycolysis, pyruvate oxidation to acetyl coA, TCA Cycle, Electron Transport Chain

Protein, carbohydrate, and fat can all break down to what?

protein: amino acids, carbs: sugars, fat: amino acids and glycerol

Note which steps are reversible and which are irreversible.

pyruvate to acetyl-CoA is irreversible and all other metalbolism steps are reversible

What must happen to protein before it can enter energy metabolism? And what how can protein provide energy?

Before amino acids can enter metabolic pathways, the amino acids must be
deaminated – lose their nitrogen-containing amino acid group, proteins provide energy by using amino acids when the body breaks down its amino acids into glucose or ketone bodies for fuel, a process that occurs when carbohydrates and fats are insufficient.

How can fat provide energy and what can it not make for energy?

Fat provides energy by being broken down into fatty acids and other components that are then used in a process called cellular respiration to generate ATP, the cell's energy currency, though this is a slower process than using carbohydrates. Fat cannot create protein

Glucogenic amino acids

can go to pyruvate and can enter the TCA cycle directly

Ketogenic amino acids

go to acetyl CoA

true

Other amino acids enter directly into the TCA cycle T or F

false

Some proteins cannot be used to make glucose (this is particularly true when there is not adequate carbohydrate in the diet) T or F

Glucose can go to pyruvate in a process called?

glycolysis and to Acetyl CoA. Glucose to pyruvate is a reversible step. But the step from pyruvate to Acetyl CoA is irreversible

Fat --> Glycerol and Fatty acids

true

Glycerol breaks down to pyruvate and can go up to pyruvate true or false

Fatty acids go to Acetyl CoA and can make glucose TorF

false

What is glycolysis?

breakdown on a molecule of glucose and is the first step in energy metabolism

What is ATP?

the main energy molecule used in human metabolic processes

What cells in the body are most metabolically active?

liver

what are the basic steps of protein synthesis.

Transcription, which occurs in the nucleus, copies DNA's instructions into messenger RNA (mRNA). In the cytoplasm, translation occurs at ribosomes, where mRNA is read to assemble a sequence of amino acids into a polypeptide chain

Know the energy sources used for a short-term fast vs long term fast once glycogen is depleted.

Once glycogen is depleted after approximately 24 hours of fasting, the body switches its primary energy sources from glucose to fat and, increasingly over time, to ketones. In prolonged fasting, the body adapts to conserve protein stores by using fat-derived energy more efficiently. 

Know the difference between -- Hunger / Satiation / Satiety

What food provides the most satiety and satiation?

protein rich foods

Energy expenditure is measured through what 3 categories? Put them in order from greatest to least

basal metabolism, physical activity, thermic effect of food

Be able to calculate the estimated energy expended on physical activities

number of kcals given X weight in lbs X number of mins

Be able to interpret a BMI

weight in lbs divided by height (inches) squared times 706 or weight in kg X height (m) squared X 706 

What is body composition?

the proportions of
muscle, bone, fat and other tissues that
make up a person’s total body weight

What are the recommended waist circumference measurements for male and female?

male > 40 inches and female > 35

What is metabolic syndrome?

a combination of risk factors—elevated fasting blood
glucose, hypertension, abnormal blood lipids, and abdominal obesity—that
greatly increase a person’s risk of developing heart disease.

leptin

a protein produced by fat cells under direction of the ob gene,
which suppresses appetite and stimulates energy expenditure.
− Acts as a hormone in hypothalamus
− Promotes negative energy balance (leading to weight loss)
− Suppresses appetite
− Increases energy expenditure

Ghrelin

Hormone ghrelin is secreted by the stomach cells, acts on the
hypothalamus.
• Increases appetite and triggers the desire to eat
• Decreases energy expenditure (leading to weight gain)
− Inverse correlation with body weight (levels are high during a low
kcal diet and lower in a positive energy state)

Environmental contributors to overweight / obesity

Obesogenic environment
includes all the circumstances that
push us toward fatness: fast food, no physicla activty

SMART goals

Specific, Measurable, Attainable, Relevant, Time-Based

Physical activity’s effect on weight control

can reduced all risks and recommended 60 min of it

What is a reasonable weight loss goal?

0.5 to 2 pounds a week

gastric band

Construct small stomach pouch
that is adjustable

What are some health risk indicators health care professionals use to assess risks?

Weight Gain Strategies

Exercising to Build Muscles, milk and juice, large portions, extra snacks, energy dense foods

Gastric Sleeve

Surgical removal of 70-85% of
stomach pouch

Gastric Bypass

Constructs small stomach pouch, outlet
directly to small intestines
− Bypasses most of stomach, duodenum, and
jejunum