lecture 3: nutrition

Question 1

why do we need food

Answer 1

chemicals for energy and components to build biomass

Question 2

what types of molecules does food give us

Answer 2

organic and inorganic

Question 3

why is food required

Answer 3

maintain favourable internal conditions
like growth, physiological processes, reproduction, regulation, maintenance and repair

Question 4

describe inorganic molecules

Answer 4

minerals –> bones, enzymes, cofactors etc

Question 5

describe organic molecules

Answer 5

vitamins –> coenzymes etc
carbs, fats, proteins –> energy for work (ATP), carbon and nitrogen skeletons for biosynthesis

Question 6

what happens to organic fuel molecules

Answer 6

oxidized to produce ATP
cellular respiration is stepwise oxidation of carbs, fats and proteins

Question 7

what things are oxidized for energy before proteins

Answer 7

carbs and fats

Question 8

kcal conversions for carbs, fats and proteins

Answer 8

1g carbs = 4kcal
1g fat = 9kcal
1g protein = 4kcal

Question 9

what are proteins broken down into

Answer 9

amino acids which are mainly used for biosynthesis

Question 10

what is metabolic rate

Answer 10

amount of energy an animal uses in a unit of time (sum of all the energy that requires biochemical reactions occurring over a time)
measured in cals or kcals

Question 11

what is BMR

Answer 11

basic metabolic rate - metabolic rate of a non growing endotherm at rest on an empty stomach and absence of stress

Question 12

BMR adult male and female

Answer 12

male = 1600-1800kcal/day
female = 1300-1500kcal/day

Question 13

what will increase metabolic rate above BMR

Answer 13

any activity that is not a basic physiological process to keep us alive

Question 14

name factors affecting metabolic rate (15)

Answer 14

physical activity
stress
mental activity
pregnancy
illness
hormones
lack of sleep
biological sex
age
genetics
temperature
weight
muscle mass
frequency of eating
type of food

Question 15

when we take in more calories than are required for metabolic rate

Answer 15

excess fuel stored in body

Question 16

name and describe the 2 locations of excess fuel storage in body

Answer 16

glycogen in liver and muscle - short term storage
fat in adipose tissue - long term storage, glucose will be converted into fat if glycogen stores are full

Question 17

name and describe the 3 energy stores that can be used when needed

Answer 17

liver glycogen - used to maintain blood sugar levels
muscle glycogen - used to provide muscles with energy during exercise
fat - used when glycogen stores have depleted

Question 18

what are essential nutrients

Answer 18

elements or molecules we must obtain from diet
cannot synthesize these
balanced diet includes all the essentials

Question 19

name the 4 categories of essential nutrients and their quantities

Answer 19

essential amino acids (9)
vitamins (organic molecules, 13)
minerals (inorganic, 15)
essential fatty acids (2)

Question 20

what 2 essential nutrients are required in very small amounts

Answer 20

vitamins and minerals

Question 21

why are 9/20 amino acids essential in diet

Answer 21

body can synthesize other 11

Question 22

name vitamins (essential nutrient)

Answer 22

ascorbic acid (vitamin c)
etc

Question 23

name minerals (essential nutrient)

Answer 23

calcium, phosphorus (bones)
iron (hemoglobin, cytochromes)
sodium, potassium, chloride (electrolyte balance)
etc

Question 24

name essential fatty acids (essential nutrient)

Answer 24

omega 3 and 6 (unsaturated)
skin, cardiac health, inflammation

Question 25

describe undernourished

Answer 25

diet does not have enough calories
glycogen used –> fat used –> body will break down proteins for fuel –> lose muscle mass –> brain becomes protein deficient –> death
if you survive can lead to irreversible damage

Question 26

describe overnourishment

Answer 26

excessive calorie intake (common in affluent nations)
once glycogen stores are full - excess fuel molecules stored as fat
leads to being overweight and obesity

Question 27

describe malnourishment

Answer 27

diet missing one or more essential nutrient
more common than undernourishment

Question 28

can you be overnourished and malnourished at the same time

Answer 28

YUHH

Question 29

what is protein deficiency

Answer 29

most common type of malnutrition
occurs when diet does not include all of the essential amino acids

Question 30

are animal products a complete source of proteins

Answer 30

yesss has 9 essential amino acids

Question 31

describe an example of protein deficiency

Answer 31

kwashiorkor - poor food supplies
symptoms = distended abdomen, enlarged liver, loss of teeth, impaired mental and physical development, severe = death

Question 32

describe hormones that regulate appetite (def)

Answer 32

hormones that act on the satiety center in the brain (hypothalamus) to regulate long term and short term appetite

Question 33

name one reason it is difficult to lose weight (set point)

Answer 33

feedback mechanisms regulate body weight around a set point

Question 34

name the 4 hormones that regulate appetite

Answer 34

leptin
PYY
insulin
ghrelin

Question 35

describe leptin (source and effect)

Answer 35

source = adipose tissue
decreases appetite
increases energy expenditure

Question 36

describe PYY (source and effect)

Answer 36

source = small intestine
decreases appetite

Question 37

describe insulin (source and effect)

Answer 37

source = pancreas
decreases appetite

Question 38

describe ghrelin (source and effect)

Answer 38

source = stomach wall
increases appetite

Question 39

how would a decrease in body fat affect hormones that regulate appetite

Answer 39

affects leptin
leptin decreases - appetite increases and metabolism decreases

Question 40

why is it difficult to lose weight (hormones)

Answer 40

adipose tissue decreases
leptin decreases
appetite increases
metabolism decreases