Ch 6

Question 1

what are the key principles of nutrition, feeding and digestion (2)

Answer 1

• to get nutrients must be able to breakdown (digest) the material
• must be able to absorb the products of digestion

Question 2

describe lactose and the 2 types

Answer 2

= primary sugar in mammalian milk

lactose persistence or lactose intolerant

Question 3

60-70% of adults lack ____ and what is it used for

Answer 3

lactase

enzyme used for complete digestion of milk (lactose)

Question 4

describe the maasai population

Answer 4

cattle raising tribes of africa
= evolved distinct mutations that allow them to synthesize lactase even when adults

60-80% exhibit lactase persistence

Question 5

what is required for absorption

Answer 5

nutrients be in their elemental form / monomers

Question 6

what is the most abundant and least abundant nutrient in the human body

Answer 6

most - proteins
least - carbohydrates

Question 7

what will generate the highest energy value

Answer 7

lipids

Question 8

are amino acids stored ?

Answer 8

NO

Question 9

describe amino acids and 2 types

Answer 9

= make up proteins

• essential AAs (we cannot produce and so must get from food)
• nonessential AAs (we can produce ourselves)

Question 10

where are proteins found? (3)

Answer 10

• enzymes
• keratin/ collagen (structure)
• membrane proteins (transport)

Question 11

do different species have different amino acids? can they vary within a species?

Answer 11

yes and yes

Question 12

what are lipids used for (3)

Answer 12

needed for energy, insulation, sex hormones

Question 13

what have chitinase and what animals do not

Answer 13

bats & rodent have but humans and rabbits do not

Question 14

what are the cofactor to enzymes

Answer 14

minerals

Question 15

how to determine the availability of minerals

Answer 15

via the soil

Question 16

what vitamins are water soluble?

Answer 16

vitamins B and C

Question 17

what vitamins are lipid soluble ? and briefly explain their roles

Answer 17

A = visual pigments(retinal), bone growth, reproductive function (activator of gene transcription)

D = calcium/phosphorus absorption

E = antioxidants, protect cells, preserving membrane phospholipids

K = required for blood clotting

Question 18

describe what the wolf spiders showed

Answer 18

if had a protein rich diet for example would chose to eat lipids later and vice versa
* wanted a complete nutrition and ate more of what was lacking

Question 19

what are the 3 types of feeding mechanisms

Answer 19

1. attack of individual prey items
2. suspension feeding
3. symbiotic association with microbes

Question 20

describe (attack individual prey items) feeding with example

Answer 20

ex. orcas
- have a strong jaw/teeth to target and subdue individual prey

Question 21

describe (suspension feeding) with example

Answer 21

ex. baleen whale
- toothless / capture food particles in water
* minimal loss of energy via a short food chain

Question 22

do short food chains deplete more or less energy than long food chains

Answer 22

short food chains deplete less energy, so final energy value is much higher

Question 23

describe symbiotic association with microbes feeding (3 types of microbes)

Answer 23

• photosynthetic autotrophs
  = use photon energy from sun to synthesis organic compounds
• chemosynthetic autotrophs
  = get energy to synthesis organic compounds via energy-releasing inorganic chemical reactions
• heterotrophs
  = use organic compounds of external origin as source of energy (in gut lumen) ex. fermenting microbes in ruminants

Question 24

contrast foregut vs hindgut fermenters

Answer 24

foregut:
• esophagus and stomach (absorb earlier in process, before food reaches small intestine)

hindgut:
• cecum and colon (slow, fermentation occurs in later part of digestive tract)

Question 25

define digestion and what principle model is used in vertebrates

Answer 25

= the enzymatic breakdown of food molecules into smaller chemical components that an animal is capable of distributing to the body tissues vertebrates - extracellular digestion

Question 26

define absorption and where does it mainly take place

Answer 26

= uptake of products of digestion from the lumen of the GI tract to the blood takes place in small intestine (midgut)

Question 27

describe GI tract

Answer 27

have different layers which each have different purposes

Question 28

peristalsis vs segmentation

Answer 28

peristalsis = adjacent segments, moves continuously down segmentation = nonadjacent segments, food moved forward then backward (well mixed)

Question 29

what spatial contexts (enzymes) are used in vertebrates (2) vs invertebrates

Answer 29

vertebrates - intraluminal enzymes - membrane-associated enzymes invertebrates - intracellular enzymes

Question 30

describe how the stomach prepares food for the small intestine (4)

Answer 30

- stomach contains gastric juices - stomach naturalizes chyme into small intestine *specific cells lining small intestine releases GI hormones which promote digestion via - having liver release bile - secretions from the pancreas

Question 31

describe structure of midgut / mechanism of glucose absorption

Answer 31

face lumen = apical face into small intestine = basalateral * glucose needs help from sodium gradient aka secondary active transport (Na/K pump on basalateral) •need ATP to use pump

Question 32

describe lipid/ FA absorption across cell (3)

Answer 32

- no ATP needed 1. surround FA with bile salts (hphilic & hphobic) to become more water soluble = becomes a micelle 2. once a micelle is created can enter via simple diffusion 3. chylomicrons (proteins attach to FAs to make soluble)