Chapter 6

Question 1

amino acids

Answer 1

contain nitrogen (amine group)are joined together by peptide bonds to form proteins

Question 2

how many amino acids and how many are essential

Answer 2

20 amino acids and 8 are essential, some may become conditionally essential (histidine)

Question 3

2 aa
3 aa
>3 aa

Answer 3

dipeptide
tripeptide
polypeptide

Question 4

building protein

Answer 4

amino acids along strand chemically attracted to or repelled from each other 
creates coil shape
spots along the coil attracted/ repelled
globular or fibrous structure 
each protein unique

Question 5

protein synthesis

Answer 5

DNA determines the amino acid sequence in proteins

different sequences account for genetic diseases ex) sickle cell

Question 6

protein digestion stomach

Answer 6

gastric acid denatures protein, and pepsin cleaves some peptide bonds

Question 7

protein digestion small intestine lumen

Answer 7

pancreatic enzymes cleave polypeptides to di-and tri-peptides brush border membrane, enzyme cleave di and tri peptides to single amino acids

Question 8

protein absorption

Answer 8

intestinal cells absorb amino acids and some di- and tri- peptides and release them into the bloodstream
carried to liver-used or released back into blood to be taken up by body cells
body can reconnect amino acids to make proteins
body can use aa for energy

Question 9

absorbing larger peptides may cause what

Answer 9

may contribute to food allergies

Question 10

functions of proteins

Answer 10

support growth and maintenance
(RBC's: 90-120 days; cells in the intestinal lining: 2 days)
structure, new tissue (hair, skin) repair
builds hormones (messenger molecules) and enzymes (catalyst) ex) growth factors, insulin

Question 11

active site

Answer 11

protein turnover: the continuous breakdown & synthesis of body proteins involving the recycling of amino acids

Question 12

functions of proteins continued

Answer 12

immune function 
building antibodies
maintaining fluid and electrolyte balance, protein transport substances in and out of cells 
maintaining acid based balance 
blood clotting 
energy

Question 13

protein utilization

Answer 13

used to build proteins
converted other small nitrogen-containing compounds
converted to other amino acids

Question 14

after removal of amino group:

Answer 14

gluconeogenesis: carbon skeleton- glucose-blood
lipogenesis: carbon skeleton-fat(for fuel or storage)

Question 15

amino acids are wasted when

Answer 15

energy is lacking
protein is overabundant
an aa is oversupplied
diet has too few essential aa

Question 16

what do you need for protein synthesis

Answer 16

adequate dietary protein with essential aa in proper amounts and energy from carbs and fat

Question 17

protein in food

Answer 17

found in all 4 food groups

Question 18

DRI for protein

Answer 18

DRI: 0.8g/kg body weight; women: 46g/day, men: 56/day
DRI minimum: 10% total energy
DRI max: 35% total energy

Question 19

what increases need for protein

Answer 19

malnutrition, infectious, state of health

Question 20

two factors influence protein quality

Answer 20

1. digestibility -animal protein >90% absorbed
   plant protein- 70-90% absorbed
2. amino acid composition- high-quality proteins contain ample amounts of all essential amino acids

Question 21

complementary proteins

Answer 21

2 or more proteins whose amino acid structures supply the essential amino acids missing from other need complementary proteins in the same day

Question 22

together they supply all four amino acids

Answer 22

legumes limiting in methionine and tryptophan

grains limiting in isoleucine and lysine

Question 23

protein digestibility-corrected amino acid score (PCAAS)

Answer 23

reflects protein digestibility
proportion of amino acids provided
scale of 0-100
egg whitem gorund beef, chicken, fat free milk, tuna =100
soybean protein= 94
combining complementary proteins can increase score

Question 24

nitrogen balance

Answer 24

nitrogen intake compared to nitrogen excretion (through urine, feces, sweat, skin)
depends on size and stage of growth

Question 25

equilibrium

Answer 25

normal healthy adult need 0.8 grams protein/kg body weight pos- growing child, preg women neg- surgery patient, astronaut

Question 26

protein energy malnutrition

Answer 26

marasmus kwashiorkor

Question 27

marasmus kwashiorkor

Answer 27

no fatty liver fatty liver anxiety, apathy apathy, irritability appetite varies loss of appetite hair, skin problems hair, skin problems world: 33,000 children die everyday, many are malnourished north america: PEM associated with chronic disease, poverty, eating disorder

Question 28

marasmus kwashiorkor: protein excess

Answer 28

>35% calories from PRO

Question 29

high intakes of animal protein

Answer 29

associated with obesity increased intake of saturated fat kidney and liver problems in animals more bone mineral loss with high intakes of purified protein more calcium lost in urine evidence mixed for effect of meat protein on Ca

Question 30

high intakes of animal protein continued

Answer 30

worsen existing kidney disease in humans increase work of they kidney to excrete nitrogen waste: amine group of amino acids is excreted as ammonia or urea does this lead to long term problems effective treatment for kidney problems = reduce protein intake

Question 31

high protein diets for weightloss

Answer 31

protein used for energy and making glucose: must remove amio group and excrete it as urea via kidneys low CHO: if

Question 32

high protein diets

Answer 32

initial rapid weight loss due to more water loss from body; loss of body fat and muscle mass in long term

Question 33

diet high in saturated fat

Answer 33

longterm cardiovascular disease risk

Question 34

diet high in dietary cholesterol

Answer 34

diet often low in some vitamins and minerals and low in fibre

Question 35

vegetarians

Answer 35

plant-based foods, some or all animal food eliminated

Question 36

vegan

Answer 36

only food from plant sources (veggies, grains, legumes, fruits, seeds, nuts)

Question 37

lacto-ovo-vegetarian

Answer 37

eats dairy and eggs, no flesh or seafood

Question 38

lacto-vegetarian

Answer 38

eats dairy, not eggs, flesh or seafood

Question 39

ovo-vegetarian

Answer 39

eats eggs, no milk products, flesh or seafood

Question 40

partial vegetarian

Answer 40

no red meat or limited quantities

Question 41

pesco-vegetarian

Answer 41

no red meat or poultry

Question 42

fruitarian

Answer 42

etas raw/dried fruits, seeds, and nuts

Question 43

macrobiotic diet

Answer 43

progressively eliminates foods: brown rice, herbal tea, water - malnutrition and death

Question 44

pros of vegetarianism

Answer 44

reduced risk of disease(obesity, heart disease, diabetes) diet is high in veggies, fruit, fibre, phytochemicals lifestyle often excludes smoking and alcohol, includes physical activity lower fat diet and leaner body maintain healthier body weight better control of caloric intake due to fibre-rich bulky foods

Question 45

pros of the omnivorous diet

Answer 45

growth is optimal complete, more digestible protein protein from meat, eggs, milk products may be easier to meet additional requirements for pregnancy, illness Vit b12, vit D, calcium, iron and zinc intake are usually adequate

Question 46

poorly planned vegetarian diets can lack

Answer 46

iron, zinc, calcium, vit B12, and vit D

Question 47

poorly planned omnivorous diets can lack

Answer 47

vit A, vit C, folate and fibre