Hnf 461 - Exam 1

Front 1

mitochondria

Back 1

a. primary site of oxygen use

b. produces most of the metabolic energy (ATP) in cells

Front 2

electron transport chain

Back 2

a. carries e-/H+ during nutrient oxidation (exothermic)

b. uses energy released to form ATP in mitochondrial matrix (endothermic)

Front 3

electron transport chain

Back 3

uses energy released by nutrient oxidation to form ATP in mitochondrial matrix

Front 4

macronutrient

Back 4

one of the 3 energy sources for body; CHO, fat, and protein

Front 5

simple combustion

Back 5

liberates energy in the form of heat only

Front 6

cellular oxidation

Back 6

salvages 40% of energy as ATP, and 60% as heat

Front 7

calorie

Back 7

1 kcal = 1000 cal = 4.18 kJ

Front 8

free energy (G)

Back 8

energy capable of doing work at constant temperature and pressure

Front 9

basal metabolic rate (BMR)

Back 9

rate at which the body expends energy to sustain basic life processes

measurement of O2 inhalation/CO2 exhalation

50-70% of daily energy expenditure

measured after 12 hour fast upon waking

Front 10

basal energy expenditure (BEE)

Back 10

BMR in units of kcal/24 hrs

Front 11

resting metabolic rate (RMR)

Back 11

10% higher than BMR

2-4 hour fast prior to measuring

65-80% of daily energy expenditure

Front 12

resting energy expenditure (REE)

Back 12

RMR in units of kcal/24 hrs

Front 13

thermic effect of food

Back 13

increase in energy expenditure

protein 20-30%
carbs 5-10%
fat 0-5%

Front 14

thermic effect of exercise

Back 14

20-40% of energy expenditure

Front 15

thermoregulation

Back 15

energy expenditure to regulate body temperature

Front 16

direct calorimetry

Back 16

measures the dissipation of heat from the body via sensible heat loss and heat of water vaporization

Front 17

indirect (respiration) calorimetry

Back 17

measures O2 consumption/CO2 expiration; proportional to metabolism, can estimate glucose oxidation

Front 18

respiratory quotient (RQ)

Back 18

ratio of CO2 expired to O2 inhaled, also called respiratory exchange ratio (R)

Front 19

AMP-activated protein kinase (AMPK)

Back 19

fuel-sensing enzyme activated by decrease in cell energy state, reflected by increase in AMP/ATP ratio

Front 20

AMPK function

Back 20

stimulates processes that generate ATP and non-vital processes that consume it

Front 21

AMPK activation

Back 21

AMP:
a. promotes phosphorylation on Thr-172
b. activates AMPK-Thr-172P
c. inhibits Thr-172 dephosphorylation

Front 22

AMPK inhibition

Back 22

inhibited when hepatic fatty acid synthesis is elevated

Front 23

hypothalamic AMPK

Back 23

stimulates food intake; inhibited by leptin

Front 24

skeletal muscle AMPK

Back 24

increases glucose and fatty acid oxidation; stimulated by leptin

Front 25

kilocalorie (kcal)

Back 25

energy to raise temperature of water one degree C

Front 26

kilojoule (kJ)

Back 26

measures work done, energy to push against force of 1 Newton for 1 meter

Front 27

gross energy of CHO, fat, and protein

Back 27

CHO = 4.1 kcal/g
fat = 9.45 kcal/g
protein = 5.6 kcal/g

Front 28

digestible energy of CHO, fat, and protein

Back 28

CHO = 98%
fat = 95%
protein = 92%

(accounts for digestion efficiency)

Front 29

metabolizable energy (ME)

Back 29

digestible energy lost in the urine

Front 30

metabolizable energy (ME) of CHO, fat, and protein

Back 30

CHO = 4 kcal/g
fat = 9 kcal/g
protein = 4 kcal/g

Front 31

metabolizable energy (ME) of alcohol and medium chain triglycerides

Back 31

7 kcal/g

Front 32

% body weight/BMR of brain, liver, heart, and kidneys

Back 32

5-6% body weight
60% BMR

Front 33

% body weight/BMR of skeletal muscle

Back 33

40% body weight
25% BMR

Front 34

calories in a lb/kg

Back 34

lb = 3500

kg = 7700

Front 35

BMR for men/women

Back 35

men = 1 kcal/kg body wt/hr

women = .9 kcal/kg body wt/hr

Front 36

GI mucosa

Back 36

epithelia has enterocytes (absorption), enteroendocrine cells, and exocrine (mucus-producing globlet) cells

Front 37

lamina propria

Back 37

GALT

Front 38

tight junctions

Back 38

prevent antigens/pathogens from entering cell; complex structure of >50 proteins

Front 39

tight junction disregulation

Back 39

leaky intestinal barrier associated with chronic inflammatory bowel diseases, type 1 diabetes, and multiple sclerosis

Front 40

commensal bacteria

Back 40

provide metabolic signals to maintain a healthy intestinal barrier

Front 41

GI disorders (6)

Back 41

GERD
IBD
ulcerative colitis
Crohn's disease
celiac disease
chronic pancreatitis

Front 42

sites of CHO digestion

Back 42

mouth, stomach, small intestine

Front 43

alpha amylase

Back 43

released by salivary glands

hydrolyzes alpha-1,4 glycosidic bonds in amylose/amylopectin to form dextrins

key enzyme in starch digestion

Front 44

dextrins

Back 44

broken into maltose in the small intestine

Front 45

maltase

Back 45

brush border (SI) enzyme that hydrolyzes maltose to glucose

Front 46

dietary fiber

Back 46

nondigestible carbs and lignin intact and intrinsic in plants

Front 47

functional fiber

Back 47

nondigestible carbs manufactured or extracted from plants; added to food with a beneficial effect to humans

Front 48

soluble fiber

Back 48

fermented in the colon; slows gastric emptying and regulates blood sugar/pH

Front 49

fermentable fibers

Back 49

lactate/short chain fatty acids
water absorption
mucosal cell proliferation
acidify colon
energy

Front 50

non-fermentable fibers

Back 50

speed up transit time
increase fecal bulk
diverticular disease

Front 51

fiber intake for men/women

Back 51

men = 38 g/day
women = 25 g/day

(age 19-50)

Front 52

glucose uptake

Back 52

requires a protein carrier to cross membranes

Front 53

GLUT 4

Back 53

transporter protein regulated by insulin; expressed in muscle, heart, and brown/white adipocytes

Front 54

carbohydrate absorption

Back 54

glucose/galactose = active transport and facilitated diffusion

fructose = facilitated transport by GLUT 5 (likely)

Front 55

Michaelis constant (Km)

Back 55

concentration of substrate needed for reaction to occur at half maximum velocity

Front 56

monosaccharide transport/uptake

Back 56

a. liver removes fructose, galactose, and some glucose

b. increase in blood glucose leads to increase in insulin secretion

Front 57

glucose transporter isoforms

Back 57

Glut 1/3 - basal tissue uptake, very low Km

Glut 2 - liver/pancreatic beta cells, high Km

Glut 3 - brain, very low Km

Glut 4 -muscle/adipose tissue, phys. Km

Front 58

fate of glucose in cells

Back 58

fuel for ATP synthesis

glycogenesis

minor uses - synthesis of ribose, NADPH, glucose for glycoprotein/glycolipid synthesis

lowest priority - substrate for fatty acid/TAG synthesis

Front 59

glucose as fuel

Back 59

brain, RBC, and skeletal muscle during vigorous exercise

(other tissues prefer fatty acids)

Front 60

glucose phosphorylation

Back 60

1st step in intracellular glucose metabolism

requires ATP

G6P trapped in cytoplasm

uses hexokinase (isoenzyme)

high Km - glucokinase
low Km - hexokinase II

Front 61

% food energy used to make ATP

Back 61

~40%

Front 62

Krebs Cycle

Back 62

substrate oxidation by H removal to NAD/FAD forms NADH/FADH

produces carbon dioxide-3/pyruvate

generates substrates for fatty acid, glucose, and amino acid synthesis

Front 63

ATP synthesis

Back 63

oxygen needed for ETS

anemia reduces performance

O2 availability limits strenuous exercise

slowed by high ATP/ADP ratio

Front 64

ATP synthesis >50%

Back 64

in muscle during strenuous exercise when substrate level phosphorylation is most active

Front 65

% energy retained during metabolism

Back 65

0%

Front 66

gastroesophageal reflux disease (GERD)

Back 66

stomach contents leak backwards into esophagus from stomach; causes heartburn and other symptoms

Front 67

cell affected abruptly by acute undernutrition

Back 67

enterocytes

Front 68

lignin

Back 68

major noncarbohydrate dietary fiber

Front 69

bile

Back 69

produced by the liver; aids lipid digestion in the small intestine