Textbook Notes (280,000)
CA (170,000)
McMaster (10,000)
LIFESCI (100)
Chapter 3

LIFESCI 2N03 Chapter Notes - Chapter 3: Hyperglycemia, Blood Sugar, Short-Chain Fatty Acid


Department
Life Sciences
Course Code
LIFESCI 2N03
Professor
Erin Westman
Chapter
3

This preview shows pages 1-2. to view the full 8 pages of the document.
!
Carbohydrate chemistry
-include sugars, starches and fiber. “-ose” name .
-Most important sugars are hexose
oGlucose fructose and galactose
Monosaccharaides
-one sugar
-hexose 6 carbons have the same chemical formula
C6H12O6 (isomer)differences are the arrangement of
atoms in space and in relation to the rest of the
molecule : structure have different function
!
Furctose!!!
*!Four!carbon!ring!
*!very!sweet!main!sugar!in!fruits!and!honey!
*!frequently!added!to!processed!food!:!high!diertary!source!
Glucose!
*!6!carbon!ring!
*!somewhat!sweet!
*!most!common!and!important!to!nutrient!!
(transported!around!the!body)!
Pryanose!!o!btw!c1!c5!
Epimer!!*different!at!1!positions!
Galactose!!
*!least!common,!not!very!sweet!!
Complex!sugars:!disaccharides!and!
polysaccharides!!
!
Condensation!
* join!together!simple!sugars!
* makes!water!!and!a!glycosidic!bond.!!
Polysaccharides!!
Glycogen!!
* found!in!meats!and!not!so!much!plants,!not!significant!source!of!carbohydrates!!
* role!is!to!store!glucose!for!future!use!in!the!liver!(can!be!found!in!the!muscle)!!
* Highly!branched!chains!that!enzymes!respond!by!attacking!them!for!glucose.!
Starches!!
* plants!cell!store!glucose!as!starches!!
* long!branch!(un)branched!chains!linked!together!!
* packed!side!by!side!in!grains/wheat/rice/potatoes/legumes!!
* amylyopectin!(branched)!or!amylose(unbranched)!!
* enzymes!break!down!it!to!maltose!then!glucose/!“resistant!starch”!–!hard!to!digest!
Fiber!
* sugars!(polymers!of!glucose)!join!by!bonds!that!can’t!be!digested!by!humans!
* !Starch:!got!glucose!bond!that!can!be!digested!because!it!is!water!*!soluble!fibers,!form!gels!(viscous)!and!
easily!digested!by!bacteria!(fermentable).!Example:!corn!oats!barley!legumes!citrus!fruits.!
* Cellulose:!got!glucose!bonds!that!cannot!be!digested!because!it!is!insoluble!fibers!that!do!not!form!gel!and!
less!fermented.!But!it!can!promote!bowel!movement!alleviate!constipation!and!prevent!diverticular!
disease.!
Note!bacteria!and!humans!shows!benefit:!mutralism.!!
Dietary!fibre:!!
* associated!with!phytic!acid!(pytate!which!is!not!good!because!it!get!excreted)!!
* not!a!dietary!fiber!but!found!in!the!some!foods!
* uncertain!if!fiber!itself!or!phytate!is!the!cause!of!!!
obind!ingested!minerals!;!which!are!then!excreted!as!an!insoluble!complex!
oexcessive!(>40g/day)!fiber!intake!could!risk!of!micronutrients!deficiencies!because!it!robs!you!of!
the!essential!nutrients!that!you!should!!be!eating.!!
* still!have!the!“*ose”!ending!but!you!need!to!know!
they!contain!2!sugars!!
oMaltose!!(two!glucose)!produce!during!start!
digestions!!
oSucrose!(glucose!+!fructose)!table!sugar!and!
sweet!taste!!

Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

You're Reading a Preview

Unlock to view full version

Only pages 1-2 are available for preview. Some parts have been intentionally blurred.

Carbohydrate!hydrolysis!!
Water!and!a!larger!sugar!makes!two!smaller!sugars!by!breaking!the!bonds!and!water.!!
!
Carbohydrate!Digestions!
Steps:!!
* Initiates!in!the!mouth!:!salivary!amylase!hydrolyzes!starched!to!dextrins!(shorter!polysacchardies)!!
* Pauses!in!the!stomach:!!HCL!and!protease!cause!the!inactive!salivary!amylase!also!the!fibre!lingers!in!the!
stomach!to!signals!fullness!
* Resumes!in!the!small!intestine:!pancreatic!amylase!does!MAJOR!part!of!hydrolyzing!starch/dextrins!to!
maltose.!
oInside!the!intestine:!the!outer!membrane!of!the!cell!the!enzymes!break!down!disaccharides!.!
Carbohydrate!Absorption!
Small%intestine:%
*Glucose!
oAbsorbed!by!active!transport!in!the!small!intestine!,!
and!some!in!mouth!lining!!
*galactose!!
oabsorbed!by!active!transport,!!
*fructose!
o!absorbed!facilitated!diffusion!which!is!very!slow.!Since!its!slow!it!doesn’t!immediately!affect!blood!
sugar.!!!(also!amylose!because!there’s!a!certain!start!region)!
Large%intestine:%
*fibres!!
oremain!undigested!and!unabsorbed!in!the!small!intestine!!to!the!large!intestine!!
obacteria!in!the!large!intestine!ferment!some!fibres!:!generate!water,!gas!and!short!chain!fatty!acid!
ocells!of!the!colon!absorb!and!use!these!short*cain!fatty!acid!:!little!energy!is!generated!by!fiber!!
* attracted!water!to!soften!stools!!
Lactose!Intolerance!!
* symptoms!after!lactose*containing!food:!bloating,!gases,!cramping,!and!diarrhea!!
* caused!by!low!or!absent!lactase!enzymes!on!intestinal!cell!membrane!–!the!enzymes!cannot!cleave!the!
bond!of!the!lactose!sugar,!therefore!the!bacteria!ferments!the!lactose!and!produces!gasses.!!
owe!are!mammals:!lactase!expression!is!highest!right!after!birth!so!infants!feed!on!milk!effetely!!
ogenetic!regulation!of!lac!operon!may!decrease!expression!of!lactase!to!5*10%!by!teenage!years!!
oalso!difference!in!ethic!groups!because!of!the!food!and!sugar!that!was!prepared!in!their!food!
(culture.)!
!!
Living!without!lactase!
* avoid!food!high!in!lactase:!milk!is!high!in!lactose!while!femented!foods!(cheese/soy!milk)!lower!in!lactose!
because!the!bacteria!already!hydrolyzed!it,!must!meet!RDA!(riboflavin!vitamin!D!and!calcium)!!
*Pre*treated!milk!with!lactase!enzymes!:!hydrolyze!lactose!before!consumptions!!
* Ingest!lactase!tablets!with!dairy!fiids!:!hydrolyze!lactose!but!must!make!it!through!the!stomach!
You're Reading a Preview

Unlock to view full version