Module 5 PART B Flashcards

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1
Q

extracellular digestion

A

digestive enzymes secreted into cavity by gland cells

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2
Q

why does extracellular digestion take a long time?

A

bc digestive enzymes are diluted in fluid

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3
Q

intracellular digestion

A

endocytosis - cells lining gastrovascular cavity move partially digested food into cell

Membrane food vacuole fuses w/ lysosome to form digestive vacuole & waste is released by exocytosis

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4
Q

crop (in more complex organisms than hydra or jellyfish which only have 1 gut cavity)

A

storage chamber where food is stored & digested slowly over time. Enlarged portion of the digestive system (in invertebrates & birds) – e.g. in a worm

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5
Q

gizzard

A

a muscular part of the gut that has grits or stone in it that helps grind the food mechanically. Gizzards are found in birds, earthworms, some fish, & some reptiles

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6
Q

how do lipids enter the cellular respiration pathway?

A

by first being broken down into glycerol & fatty acids and then entering through beta oxidation

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7
Q

animals cant synthesize the acetyl group so where does it come from & what is it used to synthesize?

A

comes form food
Acetyl group used to synthesize steroid hormones + amino acids, heme, & other compounds; fatty acids, citrate, etc.

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8
Q

amount of food needed depends on

A
  • metabolic rate (varies w age, reproductive stage, activity)
  • body mass & environmental conditions
  • types of food
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9
Q

per unit body mass SMALL animals need more/less than larger ones?

A

MORE as small animals have larger SA:V ratio

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10
Q

carnivorous teeth

A

greatly enlarged canine teeth for gripping, killing, & tearing their prey - also have incisors

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11
Q

herbivorous teeth

A

have incisors - mainly have premolars & molars

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12
Q

omnivorous teeth

A

multipurpose set of teeth

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13
Q

pyloric sphincter (constriction in tube in stomach)

A

determines how much chyme is allowed into the next section of the digestive system

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14
Q

enzymatic digestion occurs where?

A

in duodenum

In the duodenum, large lipid droplets are emulsified into smaller micelles and this increases the SA for the lipases to work in an aqueous environment to break down the lipids into monoglycerides and fatty acids

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15
Q

nutrient absorption occurs where?

A

in jejunum

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16
Q

gallstones

A

solidification of bile salts + cholesterol

17
Q

pancreas secretes. . . ?

A

bicarbonate ions to neutralize acidity of chyme

18
Q

hepatopancreatic duct

A

the common duct that secretes fluids from both the liver and pancreas into the duodenum

19
Q

what do epithelial cells secrete?

A

peptidases & enzymes for breaking down oligosaccharides

20
Q

large intestine (colon)

A

Just at start of large intestine - caecum: blind ended sac; cellulose digestion (prominent in herbivores)

In large intestine - water absorption & formation of feces

21
Q

carnivorous digestive tract

A

short, simple digestive tracts; short intestine & small caecum

22
Q

herbivorous tracts

A

long, complex digestive tracts with a large caecum

23
Q

how do herbivores digest cellulose?

A

Since most herbivores don’t have the enzyme cellulase, they have symbiotic bacteria & protists (microbes) that live in their digestive tracts & digest cellulose

These symbiotic bacteria have cellulases which hydrolyze the cellulose to produce glucose

This glucose is then used as an energy source by microbes

The microbes produce short chain fatty acids which the host then absorbs & uses as a source of energy

The short chain fatty acids promote good gut health by maintaining the integrity of the intestinal barrier

24
Q

Foregut fermenters vs hindgut fermenters

A

–> digestion of cellulose by microbes occurs BEFORE the stomach

–> Digestion of cellulose occurs AFTER stomach (e.g. horse, koala, combat, pig, rabbit)

25
Q

e.g. of foregut fermenters

A

kangaroos

26
Q

e.g. of hindgut fermenters

A

horse, koala, pig, rabbit

27
Q

Foregut fermenters & how does it work

A

The microbes are present in the large forestomach - they produce short chain fatty acids which are then used as an energy source

The microbes wash through to the hind stomach & small intestine & provide the host with a source of protein - the microbes THEMSELVES are a rich source of protein

28
Q

hindstomach

A
  • acidic & contains pepsin
  • Ruminants - special case of foregut fermenters
  • Regurgitate their food to reduce size of food particles

Ruminants have LARGE foreguts w/ four chambers:
Rumen
Reticulum
Omasum
True stomach

29
Q

Hindgut fermenters

A

Bacteria (only) present in the caecum & proximal colon

Microbes that wash through digestive tract cannot be used as protein source

This is because the microbes are living in the part of the gut that is after where the nutrients / proteins are absorbed in the small intestine

Caecum & proximal colon together are referred to as the HINDGUT

30
Q

caecotrophy

A

specialization of eating your own feces (ringtail possums)
- it is a rich source of protein w microbes
- formal fecal pellets (at night)

31
Q

Movement of water through roots

A

Water moves through the root via the apoplast and symplast until it reaches the Casparian
strip and is then forced to flow via the symplast to the central vasculature.