carbohydrate digestion

Question 1

what is a carbohydrate?

Answer 1

hydrated ketones/ aldehydes
(hydrated carbons)

Question 2

different types of carbs?

Answer 2

complex carbs - poly (chain of 10+ molecules)
simple carbs - di (2 molecules)/ mono (1)
<10 chains of saccharides= OLYGO

Question 3

polysaccharides:

Answer 3

Question 4

what affects the way amylose is metabolised?

Answer 4

= linear single chain of monosaccharides attached by glycosidic link

the glycosidic link
alpha 1-4

Question 5

how does amylopectin differ from amylose?

Answer 5

FOUND IN VEGGIES/ LEGUMES

main linear chain connected by alpha 1-4 bonds
branched chain of poly
has diff bond at branching points

alpha 1-6 bond to bond branched chains to main linear ones

Question 6

starch?

Answer 6

anything with flour has starch
polysaccharide
comes in 2 forms:

amylopectin (1-6)
amylose (1-4)

Question 7

glycogen?

Answer 7

found in animals we eat
more branched
alpha 1-6 bonding to branched chains
linear chain alpha 1-4 bonding

Question 8

why can cellulose not be digested by mammals and why is this a beneficial quality for us?

Answer 8

found in veg/ fruits

linear chains are bonded by alpha 1-4 but
the stack of chains bonded by BETA 1-4
-> not digested in animals

the pancreatic/ salivary can not break bond
used as fibre- not digested, removed in waste

Question 9

what % of our caloric intake is from carbs?

Answer 9

50%
most from starch

Question 10

3 major disaccharides in our diet?

Answer 10

1) sucrose (table sugar)
2) maltose
3) lactose

Question 11

what % of our caloric intake is from sucrose?

Answer 11

30%

Question 12

what % of our caloric intake is from lactose?

Answer 12

6%- sugar from milk

Question 13

what % of our caloric intake is from maltose?

Answer 13

1-2%

Question 14

3 main monosaccharides from our diet?

Answer 14

1) glucose - only in honey/ golden syrup in it’s simplest form
2) fructose- in fruits
3) galactose

Question 15

where do polysaccharides bond?

Answer 15

Question 16

only form of carbs our bodies can absorb?

Answer 16

monosaccharides - glucose, fructose, galactose

Question 17

only form of carbs our bodies can absorb?

Answer 17

monosaccharides - glucose, fructose, galactose

Question 18

salivary glands are found in pairs in the oral cavity, how many are there?

Answer 18

3 major pairs
multiple minor pairs

Question 19

3 major pairs of salivary glands?

Answer 19

sublingual
submandibular
parotid

Question 20

what do we find in the parotid gland?

Answer 20

zymogen granules (blue dots)
also found in pancreas

Question 21

difference between endocrine and exocrine glands?

Answer 21

exocrine (have duct) - secrete enzymes
endocrine (no duct) - secrete hormones

Question 22

where do endocrine glands secrete?

Answer 22

directly into bloodstream

Question 23

are salivary glands exocrine or endocrine?

Answer 23

exocrine

Question 24

role of salivary amylase

Answer 24

when saliva is mixed with food ball
salivary amylase= secreted from serous acini of PAROTID + SUB-MANDIBULAR salivary glands

hydrolyses 1-4 bonds of polysaccharides
-> produces oligo + di + tri saccharides

Question 25

why is the pancreas so cool?

Answer 25

it IS a gland and it had glands in it: - endocrine (islets of lanhergans- alpha, beta, gamma cells) - exocrine (duct will pass secretions into duodenum)

Question 26

what are found in the serous acini?

Answer 26

zymogen granules

Question 26

what are found in the serous acini?

Answer 26

zymogen granules

Question 27

what ph does salivary amylase work best at?

Answer 27

6.7

Question 28

role of salivary amylase once food is swallowed?

Answer 28

works for 1-2 hours in stomach deactivated at PH3 by gastric acids

Question 29

what does pancreatic amylase do?

Answer 29

- it is secrete from pancreatic exocrine acini into the duodenum through the pancreatic duct - hydrolyses alpha 1-4 bond - further digests complex carbs (alpha 1-4 bonds) that take longer to break down

Question 30

endocrine glands of the pancreas secrete which 3 cells?

Answer 30

called ISLETS of Langerhans has 3 types of cells: 1) alpha- secrete glucagon 2) beta- secrete insulin 3) gamma- secrete other hormones

Question 31

significance of parotid being similar to pancreas? zymogens being found in the serous acini of the pancreas as well? (blue dots)

Answer 31

beta cells have been found in the parotid gland trying to stimulate parotid to work as pancreas in diabetic patients

Question 32

difference between pancreatic amylase and salivary amylase?

Answer 32

1) pancreatic amylase works at wider range: 6.7-7 2) pancreatic amylase can stay active for longer as pancreas secretes bicarbonate as well -> keeps PH alkaline

Question 33

what do we get as products of hydrolysis by pancreatic amylase?

Answer 33

1) dextrins (disaccharides) 2) oligo saccharides STILL NOT AT MONOSACCHARIDES

Question 33

what do we get as products of hydrolysis by pancreatic amylase?

Answer 33

1) dextrins (disaccharides) 2) oligo saccharides STILL NOT AT MONOSACCHARIDES

Question 34

which enzymes around in intestinal epithelial cells?

Answer 34

brush border enzymes OPTIMAL PH= 7.8 (pancreatic bicarbonate make ph alkaline) found on apical side of intestinal epithelial cells formed of folds in folds, in microvilli, contain enzymes which are secreted into small intestine -> further hydrolyse carbs

Question 35

which sugars do brush border enzymes hydrolyse?

Answer 35

maltose (maltase) sucrose (sucrase) lactose (lactase)

Question 36

deficiency in lactase enzyme?

Answer 36

leads to lactose intolerance as lactose can not be hydrolysed properly

Question 37

causes of deficiency of lactase enzyme?

Answer 37

1) congenital (certain ethnic groups have inherent lactose intolerance) 2) acquired- infections, inflammation, injury to intestinal cells

Question 38

how do you get temporary lactose intolerance?

Answer 38

by ROTA virus (tummy bug) not treatable avoiding milk/ dairy reduces symptoms - can add lactase enzyme to dairy products

Question 39

how are oligo and disaccharides digested to monosaccharides?

Answer 39

by brush border enzymes

Question 40

deficiency of some brush border enzymes can lead to which pathology?

Answer 40

lactose deficiency= lactose intolerance