Exam 2 Crouch Flashcards
glucose, AA and fat enter digestion where?
glucose- as glucose
AA- as pyruvate, Acetyl CoA, Citric acid cycle
Fats- B-oxid in pyruvate to acetyl CoA
what is intermediary metabolism?
taking in nutrients with a step by step process to generate
1) energy (degradation process)
2) new molecules (synthetic process)
what does “integrated nature” of biochem mean?
pathways are linked and interdependent AND opposing pathways are regulated reciprocally
what is metabolism?
the sum of all chemical changes occurring in a CELL, a tissue or the body
difference in catabolism and anabolism?
catabolism= produce energy and BREAKDOWN= degrative anabolism= consume energy and CREATE= synthesis
how does ATP give off energy? do we store it?
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
from least to most, list what gives off the most energy: ATP, creatine phosphate, glucose in plasma, glycogen in liver, fat
ATP= 1 sec creatine= 5-30 sec glucose in plasma= 4 min glycogen= 90 min fat= 800 miles
The body it the BEST _____ (try to do more with less)
conservative
what is the recurring motif for acetate degradation in TCA, lysine degradation, fatty acid degradation AND fatty acid synthase?
**acetate, lysine and fat degradation=
oxidation> hydration> oxidation
**fat synthesis= reduction> dehydration> reduction
primary 3 ways metabolictic motifs/processes are regulated?
1) amount of enzymes
2) catalytic activity of the enzymes
3) accessibility of substrates
opposing reactions are often segregated in separate compartments, example?
FA synthesis in cytosol, FA degradation in mitochondria
what are the 4 biomolecules?
1) nucleic acids =DNA/RNA
2) proteins= amino acids
3) carbohydrates= aldehydes and ketones
4) lipids= hydrogenated carbon chains and rings
where do anabolic pathways start and catabolic end?
at the ‘backbone’ or ‘hub’ of metabolism– glycolysis and the TCA cycle
disaccharides are held together by what bond?
glycosidic bonds
what is ‘dextrose’? it is a resonance structure with?
dextrose= D-glucose
D-glucose and D-fructose are resonance structures
difference between Furan and Pyran?
Furan= 5 membrered ring Pyranose= 6 membered ring
how do you decide if a cyclized saccharide anomer is alpha or beta? which one is more common?
alpha= C1-OH group down
beta= C1-OH group up
**2/3 beta and 1/3 alpha
almost all N-glycosidic linkages have a alpha or beta configuration?
beta
what is table sugar?
sucrose = glucose + fructose
what are the disaccharides sucrose, lactose, maltose made of?
sucrose = glucose + fructose lactose= glucose + galactose maltose= glucose + sucrose
lactose intolerance is a metabolic or digestive issue? describe this
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
difference in oligosaccharides and polysaccharides? what is a homopolymer?
oligosaccharides are 3 to 9 linked monosaccharides AND polysaccharides are 10 or more
**homopolymer= all the monosaccharides in a chain are the same
what is glycogen? what bonds are present?
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)
what do branched structures do?
assist with solubility and storage. In glycogen, there are branches about every 10 monomers
what is starch? How many forms?
a homopolymer of glucose but is the storage form for PLANTS. two forms
1) amylose
2) amylopectin
what is starch hydrolyzed by?
alpha-amylase, an enzyme secreted in saliva and the pancreas
the difference between amylose and amylopectin?
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)
what is the difference between amylopectin and starch? how are they the same?
both have alpha 1,4 linear bonds and alpha-1,6 branches bonds BUT GLYCOGEN HAS a lot MORE branched bonds
what is cellulose?
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
why is cellulose considered dietary fiber?
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
insoluble verses soluble dietary fiber?
- insoluble= indigestible roughage, fibrous and stringy, whole wheat, fruits, veggies
- soluble= indigestible slimy or sticky, delays absorption of some nutrients; oats/barley
what are fructons?
LEVANS, polymers of fructose; made by plants and microorganisms; short chains from plants and long chains from bacteria
what is dextran? important for? used for?
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
what are glycosaminoglycans? (GAGs) they include what special sugar?
- 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
GAGs are often found paired why? functions?
proteins. GAGs and proteoglycans attract water with their negative charge to provide lubrication and cushioning
what are the 3 ways that carbohydrates can be linked to proteins?
1) asparagine (N-linked)
2) threonine (O-linked)
3) serine (O-linked)
only ______ can be absorbed in jejunum?
monosaccharides (enzymes to degrade sucrose, maltose, lactose, isomaltose)
salivary (ptylin) and pancreatic alpha-amylase hydrolyze?
internal alpha 1,4 linakes
*they are ENDO-amylases
reducing sugars can form?
free aldehyde group that can readily be oxidized
*only the end glucose residue can open to a straight chain to generate free aldehyde
what are NON-reducing sugars?
closed ring sugars, sucrose, strach, amylose, amylopectin, glycogen
what are reducing sugars?
what ones only work in chain form?
in solution?
have 1/2 reducing power?
- all monosaccharides, aldoses, and ketoses in OPEN chain form
- glucose
- fructose IF IN SOLUTION
- maltose and lactose (1/2 reducing power)
