Exam 2 Crouch

Question 1

glucose, AA and fat enter digestion where?

Answer 1

glucose- as glucose
AA- as pyruvate, Acetyl CoA, Citric acid cycle
Fats- B-oxid in pyruvate to acetyl CoA

Question 2

what is intermediary metabolism?

Answer 2

taking in nutrients with a step by step process to generate

1) energy (degradation process)
2) new molecules (synthetic process)

Question 3

what does “integrated nature” of biochem mean?

Answer 3

pathways are linked and interdependent AND opposing pathways are regulated reciprocally

Question 4

what is metabolism?

Answer 4

the sum of all chemical changes occurring in a CELL, a tissue or the body

Question 5

difference in catabolism and anabolism?

Answer 5

catabolism= produce energy and BREAKDOWN= degrative
anabolism= consume energy and CREATE= synthesis

Question 6

how does ATP give off energy? do we store it?

Answer 6

it is hydrolyzed, gives off phosphate; it’s a HIGH ENERGY sourse in biological systems; we have VERY LITTLE STORED ATP and must regenerate it all the time

Question 7

from least to most, list what gives off the most energy: ATP, creatine phosphate, glucose in plasma, glycogen in liver, fat

Answer 7

ATP= 1 sec
creatine= 5-30 sec
glucose in plasma= 4 min
glycogen= 90 min
fat= 800 miles

Question 8

The body it the BEST _____ (try to do more with less)

Answer 8

conservative

Question 9

what is the recurring motif for acetate degradation in TCA, lysine degradation, fatty acid degradation AND fatty acid synthase?

Answer 9

**acetate, lysine and fat degradation=
oxidation> hydration> oxidation
**fat synthesis= reduction> dehydration> reduction

Question 10

primary 3 ways metabolictic motifs/processes are regulated?

Answer 10

1) amount of enzymes
2) catalytic activity of the enzymes
3) accessibility of substrates

Question 11

opposing reactions are often segregated in separate compartments, example?

Answer 11

FA synthesis in cytosol, FA degradation in mitochondria

Question 12

what are the 4 biomolecules?

Answer 12

1) nucleic acids =DNA/RNA
2) proteins= amino acids
3) carbohydrates= aldehydes and ketones
4) lipids= hydrogenated carbon chains and rings

Question 13

where do anabolic pathways start and catabolic end?

Answer 13

at the ‘backbone’ or ‘hub’ of metabolism– glycolysis and the TCA cycle

Question 14

disaccharides are held together by what bond?

Answer 14

glycosidic bonds

Question 15

what is ‘dextrose’? it is a resonance structure with?

Answer 15

dextrose= D-glucose

D-glucose and D-fructose are resonance structures

Question 16

difference between Furan and Pyran?

Answer 16

Furan= 5 membrered ring
Pyranose= 6 membered ring

Question 17

how do you decide if a cyclized saccharide anomer is alpha or beta? which one is more common?

Answer 17

alpha= C1-OH group down
beta= C1-OH group up
**2/3 beta and 1/3 alpha

Question 18

almost all N-glycosidic linkages have a alpha or beta configuration?

Answer 18

beta

Question 19

what is table sugar?

Answer 19

sucrose = glucose + fructose

Question 20

what are the disaccharides sucrose, lactose, maltose made of?

Answer 20

sucrose = glucose + fructose
lactose= glucose + galactose
maltose= glucose + sucrose

Question 21

lactose intolerance is a metabolic or digestive issue? describe this

Answer 21

digestive issue; don’t use it you lose it). made into methane and hydrogen gas causing gut distention and diarrhea. caused by age, being a woman, more common in natives and asians

Question 22

difference in oligosaccharides and polysaccharides? what is a homopolymer?

Answer 22

oligosaccharides are 3 to 9 linked monosaccharides AND polysaccharides are 10 or more
**homopolymer= all the monosaccharides in a chain are the same

Question 23

what is glycogen? what bonds are present?

Answer 23

homopolymer of glucose; carbohydrate storage form for ANIMALS, it highly ranched with BOTH alpha-1,4glycosidic bones (linear) and alpha-1,6 glycosidic bonds (branch point)

Question 24

what do branched structures do?

Answer 24

assist with solubility and storage. In glycogen, there are branches about every 10 monomers

Question 25

what is starch? How many forms?

Answer 25

a homopolymer of glucose but is the storage form for PLANTS. two forms

1) amylose
2) amylopectin

Question 26

what is starch hydrolyzed by?

Answer 26

alpha-amylase, an enzyme secreted in saliva and the pancreas

Question 27

the difference between amylose and amylopectin?

Answer 27

amylose= unbranched starch with ONLY alpha 1,4 glycosidic bonds
** amyopectin= branched starch with both alpha 1,4 glycosidic bonds in linear chain and alpha- 1,6 glycosidic bonds at branch points (not as branched as glycogne)

Question 28

what is the difference between amylopectin and starch? how are they the same?

Answer 28

both have alpha 1,4 linear bonds and alpha-1,6 branches bonds BUT GLYCOGEN HAS a lot MORE branched bonds

Question 29

what is cellulose?

Answer 29

homopolymer of glucose that DO NOT BRANCH, only held together by BETA 1,4 glycosidic linkages, high tensile strength, MOST prevalent organic compound on earth

Question 30

why is cellulose considered dietary fiber?

Answer 30

mammals do NOT synthesis an enzyme that can break beta 1,4 bonds therefore cellulose is not digested
**some mammals like rummants have gut microorganisms that will break cellulose down for them

Question 31

insoluble verses soluble dietary fiber?

Answer 31

• insoluble= indigestible roughage, fibrous and stringy, whole wheat, fruits, veggies
• soluble= indigestible slimy or sticky, delays absorption of some nutrients; oats/barley

Question 32

what are fructons?

Answer 32

LEVANS, polymers of fructose; made by plants and microorganisms; short chains from plants and long chains from bacteria

Question 33

what is dextran? important for? used for?

Answer 33

homopolymer of glucose with a main chain of alpha 1,6 and branch points roughly every 20 glucose residues with alpha 1,3****
*produced by strep. mutans and are important components of DENTAL PLAQUE and used intravenously as volume expanders after a hemorrhage

Question 34

what are glycosaminoglycans? (GAGs) they include what special sugar?

Answer 34

• anionic polysaccharide chains of repeating disaccharide unit
• include chondroitin sulfate, keratin sulfate, heparin sulfate, dermatan sulfate, hyaluronate found on animal cell surfaces
• amino sugars glucosamine and galactosamine

Question 35

GAGs are often found paired why? functions?

Answer 35

proteins. GAGs and proteoglycans attract water with their negative charge to provide lubrication and cushioning

Question 36

what are the 3 ways that carbohydrates can be linked to proteins?

Answer 36

1) asparagine (N-linked)
2) threonine (O-linked)
3) serine (O-linked)

Question 37

only ______ can be absorbed in jejunum?

Answer 37

monosaccharides (enzymes to degrade sucrose, maltose, lactose, isomaltose)

Question 38

salivary (ptylin) and pancreatic alpha-amylase hydrolyze?

Answer 38

internal alpha 1,4 linakes

*they are ENDO-amylases

Question 39

reducing sugars can form?

Answer 39

free aldehyde group that can readily be oxidized

*only the end glucose residue can open to a straight chain to generate free aldehyde

Question 40

what are NON-reducing sugars?

Answer 40

closed ring sugars, sucrose, strach, amylose, amylopectin, glycogen

Question 41

what are reducing sugars?
what ones only work in chain form?
in solution?
have 1/2 reducing power?

Answer 41

• all monosaccharides, aldoses, and ketoses in OPEN chain form
• glucose
• fructose IF IN SOLUTION
• maltose and lactose (1/2 reducing power)