M2 L8+9

Question 1

outline the major dietary carbs available to animals

Answer 1

maltose, sucrose, lactose

Question 2

briefly outline digestion of carbs and proteins in animals

Answer 2

Proteins are broken down by pancreatic and gastric hydrolases into amino acids
Complex carbohydrates are broken down by hydrolases into monosaccharides

Question 3

describe the role of ATP in metabolism and explain why it needs to be continually recycled

Answer 3

it is used as an immediate donor of energy, high turnover, cannot be stored

Question 4

describe the way in which oxidation and reduction reactions help in energy conservation

Answer 4

for every oxidation reaction, there is a coupled reduction reaction
electrons are transferred and energy is conserved on electron carriers

Question 5

relate free energy changes associated with hydrolysis of phosphorylated metabolic intermediates to ATP synthesis and hydrolysis

Answer 5

the bonds formed after hydrolysis are lower in energy than before

Question 6

explain why metabolic pathways must be regulated

Answer 6

to prevent from cells going the wrong way.
because there are lots paths that merge into each other and are sometimes used for shortcuts, cells have different needs at different times

Question 7

outline the most common ways that metabolic pathways are regulated

Answer 7

key enzyme catalyzed reactions
amount of enzyme produced
allosteric regulation
covalent modification

Question 8

outline the importance of glucose in animal metabolism

Answer 8

it is absorbed from the intestinal tract to the all the cells in the body, major fuel for the brain, precursor for many other molecules

Question 9

explain why ruminants are not able to obtain glucose directly from their diet

Answer 9

all the foodstuff goes directly to the rumen where microorganisms degrade the plant polysaccharides to glucose for their own use to make ATP, no glucose is left for the animal

Question 10

describe the by products of rumen fermentation that are available to ruminants

Answer 10

volatile fatty acids;
acetate (2c), for ATP synthesis
propionate,(3c) reserved for glucose synthesis in liver
butyrate, (4c) fatty acid biosynthesis, some for ATP synthesis

Question 11

outline the major pathways for carbohydrate metabolism

Answer 11

polysaccharides, monosaccharides, glycolysis (glucose, glyceraldehyde-3-phosphate, pyruvate) to fermentation of respiration

Question 12

Explain the role of electron carriers in the conservation of energy

Answer 12

Electrons represent a store of free energy. The electron carriers temporarily store these electrons to be passed on to another substrate or carrier so that the free energy is not lost.