Simple Stomach 1

Question 1

What does having a simple stomach mean?

Answer 1

-monogastric
-no compartments

Question 2

What does gluconeogenesis do?

Answer 2

-Make glucose
-synthesis of glucose from non-carbohydrate sources

Question 3

Where does gluconeogenesis occur?

Answer 3

-the cytosol of cells

Question 4

What does the irreversible enzyme step pyruvate carboxylase do?

Answer 4

-carboxylates pyruvate to oxaloacetate (added a carbon)

Question 5

What does the irreversible enzyme step phosphoenolypyruvate carboxykinase (PEPCK) do?

Answer 5

-converts oxaloacetate to phosphoenolypyruvate

Question 6

What does the irreversible enzyme step Fructose-1,6-biphosphatase do?

Answer 6

-removes 1 phosphate group from fructose-1,6-biphosphate

Question 7

What does the irreversible enzyme step Glucose-6-phosphate do?

Answer 7

-removes the phosphate group to liberate free glucose

Question 8

What do ruminants extensively utilize that is produced from fermentation of carbohydrates in the rumen?

Answer 8

-propionate (gluconeogenesis VFA)

Question 9

What happens when carbohydrates are extensively fermented?

Answer 9

-no or very little glucose is absorbed from the small intestine intact

Question 10

What is propionate converted to?

Answer 10

-succinyl-CoA

Question 11

What does succinyl-CoA proceed to?

Answer 11

-the TCA cycle to oxaloacetate to enter gluconeogenesis

Question 12

Do ruminants depend exculsively on gluconeogenesis?

Answer 12

Yes

Question 13

What are substrates from gluconeogensis?

Answer 13

-Amino acids

Question 14

How are amino acids utilized?

Answer 14

-as carbon skeletons for gluconeogenesis
-entry points into TCA cycle to get to oxaloacetate and pyruvate vary by amino acids

Question 15

What is easy to convert to pyruvate?

Answer 15

Alanine

Question 16

What control gluconeogensis?

Answer 16

Hormones

Question 17

What does insulin do to gluconeogenesis?

Answer 17

strongly inhibits it

Question 18

What does glucagon do to gluconeogenesis?

Answer 18

promotes it

Question 19

What does cortisol do to gluconeogenesis?

Answer 19

stimulates it

Question 20

What can simple stomach animals be?

Answer 20

-carnivores
-herbivores
-omnivores

Question 21

What influences the structures of the digestive tract?

Answer 21

-diet feedstuff composition

Question 22

What do more digestible diets require?

Answer 22

-less digestive capacity in the gastrointestinal tract

Question 23

What do more plant material and more fiber require?

Answer 23

-more capacity and complexity in the GI tract to facilitate digestion

Question 24

What is important for fiber digestion in ruminants?

Answer 24

-retention
-capacity

Question 25

If an animal eats more plant material what part of their digestive tract is larger?

Answer 25

Large intestine

Question 26

What does fermentation improve?

Answer 26

-plant fiber digestion

Question 27

Where does most fermentation take place in a simple stomach animal?

Answer 27

-in the hindgut
-large intestine

Question 28

As a percentage of total gut volume who has the greatest fermentation capacity?

Answer 28

-ruminants, but some non-ruminants come close

Question 29

Where do carbohydrates that escape digestion in the small intestine in simple stomach animals go?

Answer 29

-enter the large intestine for fermentation

Question 30

What enters the large intestine?

Answer 30

-plant fiber
-possibly starch

Question 31

What does fermentation by bacteria produce?

Answer 31

-VFA
-CO2
-H2
-methane (variable)