Midterm Section 3.2 - Lipids and Diabetes Flashcards
(42 cards)
which is the only non-plant sugar?
lactose
photosynthesis materials and products
6 water, 6 carbon dioxide –> 1 glucose, 6 oxygen
monosaccharide structure
fructose - cyclo pentane, glucose/galactose - cyclohexane
disaccharide compositions
sucrose - fructose + glucose
maltose - glucose + glucose
lactose - glucose + galactose
condensation and hydrolysis
condensation reaction makes a bond and releases a water, hydrolysis uses a water to break a bond
polysaccharide bonding patterns
glycogen has many alpha 1,6 bonds, very branched
starch has many alpha 1,4 bonds, very condensed
cellulose has beta 1,4 bonds that humans cannot digest
salivary amylase is inactivated
by the pH in the stomach
where are the enzymes for disaccharides?
at brush border to finish digestion of complex carbohydrates
what is lactose intolerance? lactase persistence?
a reduction in production of lactase enzyme at the brush border
(gene is activated less with time)
75% of the world is lactose intolerant
lactase persistence is a gene variant in people from northern countries in the promoter region of the lactase gene
why does lactose intertolerance lead to diarrhea symptoms?
lactose that gets into the colon has osmotic effect
bacteria can ferment lactose
how is fructose metabolized?
in liver to glucose or fatty acids (preferential) (sucrose is fructose and glucose)
can lead to fatty liver disease and hyperlipidemia
how does anaerobic respiration work?
krebs cycle cannot occur, and pyruvate cannot exit cell
pyruvate converted to lactate, which is transported to the liver to be made into glucose
when do ketones form?
when krebs cycle doesn’t complete oxidation of acetyl coA and pairs them to form ketone body
ketones lead to acidosis because they are acids
glucose availability prevents ketosis
glycogen stores
1% of muscle mass
about 400 kcal (1 day of fasting) total
1/3 in liver, 2/3 in muscle
highly hydrated (loss of glycogen, water loss weight loss)
Blood glucose levels
homeostasis: 5-10 mmol/L
hypoglycemia - below 5 mmol/L
hyperglycemia - above 10 mmol/L
insulin stimulates
uptake of glucose into cells
anabolic, storage of glycogen
conversion of excess glucose into fat
glucagon stimulates
catabolic, breakdown of glycogen from liver
release of glucose into the blood
what is glycemic index? glycemic load?
GI: glycemic response 50g of food/glycemic response to 50g of glucose x 100%
GL: per serving of carbs
recommended max added sugar intake percentage and grams
7-10% of calories per day
225-325g of added sugar per day
why can’t humans digest fiber?
because of the beta glycosidic bonds
insoluble fiber description and benefits
cell walls and structural elements
cellulose, lignin and hemicellulose, resistant starch
non viscous, tough and stringy
less fermentable
benefits: cleans colon out (scraping), provides bulk
downsides: binds cations/minerals
soluble fiber description and benefits
cement/glue of plants
pectin, gums, mucilages
viscous, fermentable, gummy
benefits: binds cholesterol and bile acids for recycling, improves glycemic control
downsides: decreases fat soluble vitamin absorption
products of intestinal bacteria fermentation of fibers
gases: CH4, H2, CO2
SCFAs: acetate, butyric acid, propionate (acids)
provide energy for colonocytes and decrease pH
bile reabsorption happens where?
terminal ileum of the SI, to be returned to the liver