Week 3 Flashcards
what are the two types of carbohydrates?
simple and complex
what are simple carbohydrates
monosaccharides (1 polymer)
disaccharide (2 polymers)
what are complex carbohydrates
oligosaccharides (3-10 polymers)
polysaccharides (>10 polymers)
what are three monosaccharides
glucose, fructose, galactose
what is glucose
- blood sugar (dextrose)
- essential CHO- main source of energy for brain and nerves
- travels through our bloodstream
- what we break down into Krebs cycle to create ATP
what is fructose
fruit sugar
sweeter than glucose or galactose
what is galactose
- part of lactose (milk sugar)
- freed during digestion
what are three disaccharides?
sucrose, lactose, maltose
what is sucrose?
- fructose+glucose= sucrose
- table sugar
what is lactose?
- galactose+glucose=lactose
- sugar in milk
- poorly digested in some (lactose intolerance)
what is maltose?
- glucose+glucose = maltose
- produced when starch is broken down
- occurs during the fermentation process that yields alcohol
what is hydrolysis
breaking a bond of two molecules using water
how do you create a disaccharide?
using a condensation reaction- the removal of water can bind two polymers together
what are three polysaccharides?
starch, fibre and glycogen
what is starch?
source of glucose
storage form of glucose in plants
what do we do with fibre
indigestible: can’t be broken down by enzymes
- send to colon
- softens stool
- slows digestion of glucose
what is glycogen
storage form of CHO in the liver and muscles in humans and animals
what are the two types of fibre?
soluble (viscous)
insoluble (non-viscous)
what is soluble fibre?
-dissolves in water
- add thickness to food
- helps stool formation
- helps regulate blood glucose
- forms gel
what is butyrate
- bacterial fermentation of soluble fibres produces small fat-like molecules such as butyrate
- butyrate provides energy to colon cells and improves microbiota
what is insoluble fibre?
- do not dissolve in water
- helps move stool through the large intestine
- do not form gel
what are 5 benefits of fibre?
- lower blood cholesterol
- blood glucose control
- healthy weight management
- lower rates of colon cancer
- maintenance of gut health
what are the two ways fibre lowers blood cholesterol, and how
- vacuum-like action: foods rich in soluble fibres bind with cholesterol-containing bile in the intestine and then are carried out in faces
- prevention: bacterial fermentation of fibre releases short-chain fatty acids (e.g butyrate) that help reduce cholesterol synthesis in liver
how does fibre help blood glucose control?
- reduced risk of diabetes
- glucose absorption slowed down when fibre traps nutrients and delays transit
- prevents surges in blood glucose, less insulin release, improves insulin sensitivity over time
how does fibre help healthy weight management?
- foods rich in complex CHO are often low in fats and added sugars
- promote feeling of fullness and satiety
how does fibre lower rates of colon cancer?
- assumed that it’s related to the fermentation of short-chain fatty acids that have anti-carcinogenic properties by speeding the removal of harmful carcinogenic agents
how does fibre maintain gut health?
- cellulose enlarges and softens the stool to help prevent constipation
how does fibre prevent hemorrhoids?
- less likely to occur when stools are soft and pass through easily
how does fibre prevent appendicitis?
prevented intestinal contents from moving through and not permitting bacterial growth
how does fibre prevent diverticula
fibre stimulates GIT muscles to retain their strength
where does digestion start and what is it initiated by?
digestion starts in the mouth and is initiated by salivary amylase
what happens to starch in the mouth
split starch into maltose
what happens in the small intestine?
- the majority of CHO digestion occurs here
- pancreatic amylase: digestion of starch into shorter glucose chains and maltose
- The outer membrane of intestinal cells secrete enzymes: lactase, sucrase, maltase
- fibre is not digested here
what happens in the large intestine?
- fibre and resistant starch travel unchanged to the colon
- fibre attracts water to soften stool
- bacterial fermentation may occur and odorous gases may be produced
what is absorption
- occurs in the small intestine
- enter cells (glucose/galactose) of the lining of the intestine via active transport
- may also be absorbed via facilitated transport
what does the liver do with galactose and fructose?
converts galactose and fructose to glucose
what is glucose regulated by?
regulated by the pancreas via insulin and glucagon (hormones)
