Lecture 21 -- review questions Flashcards
what is nutrition?
the process of providing or obtaining the food necessary for health and growth
what is digestion?
catabolic process that breaks down large food molecules to monomers (chemical building blocks)
what is hydrolysis?
the enzymatic breakdown of any food molecule is hydrolysis
involves adding a water molecule to each molecular bond to be broken (lysed)
what are the monomers of carbs, proteins, lipids, and nucleic acids?
carbs – monosaccharides
proteins – amino acids
lipids – fatty acid, glycerol
nucleic acids – nucleotide
what is the absorption?
the process of moving substances from the lumen of the gut into the body
capillaries (villi) –> hepatic portal system –> liver
what is metabolism?
sum of all biochemical reactions in the body
- anabolism – build
- catabolism – break down
what is the main difference between catabolism and anabolism?
both are types fo metabolism (sum of all biochemical reactions in the body)
anabolism – all reactions that build larger molecules or structures from smaller ones
catabolism – all processes that break down complex structures to simpler ones
what is a nutrient?
a substance in food the body uses to promote growth, maintenance, and repair
what is an essential nutrient?
those that are inadequately synthesized by body cells and must be ingested in the diet
what are the 6 major nutrient categories?
(1) carbs
(2) protein
(3) fats
(4) water
(5) vitamins
(6) minerals
what is the difference b/n micronutrients and macronutrients?
macronutrients
- must be consumed in relatively large quantities
- supply energy and are used as building blocks
micronutrients
- only small quantities are required
what are the 4 macronutrients?
(1) carbs
(2) protein
(3) fats
(4) water
what are the two micronutrients
(1) vitamins
(2) minerals
what is meant by percent (%) of daily caloric intake?
recommended proportion of energy supply
what percentage of your daily caloric intake should carbohydrates, proteins, and fats make up?
carbohydrates – 45-65%
proteins – 10-35%
fats – 20-35%
what macronutrient should we eat most as a percentage of total calories?
carbohydrates (45-65%)
what are calories?
1 calorie = the amount of heat (energy) needed to raise the temperature of 1 gram of water by 1 degree C
what is the difference b/n calories, Calories, and kilocalories?
1000 calories = 1 Calorie (C) = 1 kilocalorie (kcal)
what does Calorie represent?
units that represent the ability of food to be converted by the body into energy
what are the 3 energy-yielding nutrients?
(1) carbohydrates
(2) proteins
(3) fats
how many calories are produced when 1 gram of carbohydrates, fats, and proteins are fully oxidized in our body?
carbohydrates – 4 kcal/g
proteins – 4 kcal/g
fats – 9 kcal/g
what is an empty calorie?
calories that contribute to your total caloric intake but supply little or no nutritional value
ex. alcohol or sugary foods
why is alcohol not a class of nutrients despite its high-calorie content?
alcohol (7.1 kcal/g) promotes malnutrition by providing “empty calories” –> they decrease appetite but fails to provide other nutrients
which of the following vitamins are water-soluble or lipid-soluble: A, B, C, D, E, K?
water-soluble:
- B, C
“white buffalo chicken”
lipid-soluble:
- A, D, E, K
“LADEK”
“lost apples don’t eat kale”
which of the 2 vitamin groups, water-soluble or lipid-soluble, has a higher risk of accumulating in your body until reaching toxic levels? Why?
lipid-soluble
they are absorbed with dietary lipids so can be stored in body
how are water-soluble vitamins absorbed and excreted from the body?
absorbed w/ water by simple diffusion
(water is absorbed by osmosis, following the absorption of salts and organic nutrients that create an osmotic gradient)
excreted in urine –> not stored in body
how is vitamin B12 absorbed from the intestines?
needs to bind to intrinsic factor (IF) secreted by the stomach’s parietal cells – specific receptor
is ferrous (Fe2+) iron or ferric (Fe3+) iron more absorbable?
Fe2+ (ferrous iron) is more absorbable
what is the function of ferroportin?
transports iron into the bloodstream
where can you find ferroportin?
enterocytes in duodenum
liver
macrophages
what is the function of transferrin?
take up Fe2+ from FPN to transport Fe2+ throughout the body via bloodstream to various tissues
- liver (storage)
- bone marrow (hemoglobin synthesis)
- muscle (myoglobin synthesis)
what happens to the iron released by macrophage degradation of senescent red blood cells?
is it recycled?
Fe2+ from macrophage degradation gets taken up by transferrin to spread throughout bloodstream –> reaches organs like bone marrow, muscle, and liver
it is recycled/used again
why does transferrin transport iron to bones and muscles?
bones – hemoglobin synthesis (erythropoiesis – make RBCs)
muscles – myoglobin synthesis
what is ferritin?
iron storage protein that stores excess iron
present in liver, spleen, muscle tissue, and bone marrow