WEEK 3

Question 1

What is Carbohydrates

Answer 1

provides nearly all of the energy the human brain uses daily
- the rest of the body energy is from fat

Question 2

What are monosaccharides and 3 types

Answer 2

• simple sugars
• glucose = essential energy source, also known as blood sugar and absorbs radidly
• frutose = occurs naturally in honey and fruits, added to many foods in the form of high fructose corn syrup
• galactose: rarely occurs naturally as a single sugar(mono form)

Question 3

What are dissacahrides and the 3 types

Answer 3

• sugars composed of pairs of mono
• sucrose: glucose+fructose(table sugar)
  -lactose:glucose+galactose(milk sugar)
  -> principal carb in milk
  -maltose:glucose+glucose(malt sugar)
  -> produced when starch breaks down
  -> occurs during digestion

Question 4

How to make a dissacharide

Answer 4

• reaction: condensation
• links 2 monos together
  -> hydroxyl(OH) + hydrogen atom(H) link together w O molecule to form H20

Question 5

How to break a dissacharide

Answer 5

• hydrolysis
  -> h20 splits = h and OH
  -> commonly occur during digestion

Question 6

What are polysaccharides and 3 types

Answer 6

• many glucose units and monnacharides srung together
  -glycogen
• starches
• fibre

Question 7

Describe the structure of glycogen and functon

Answer 7

provides about half the energy muscle and other body tissues use
- storage form of carb/glucose
- glucose molecules are linked together in highly branched chains=prevents hydrolysis
- when needed, enzymes attack the branches = releasing glucose
- liver and muscle cells can stimulate this

Question 8

Describe the function and strcture of starches

Answer 8

• plants store glucose as starche
• long, branched or unbranched chains of hundreds or thousands of glucose molecules linked together
• packed side by side in grains,root crops and tubers, legumes,
• when plant consumed= body hyrdolyses starch to glucose

Question 9

Describe the function and strcture of dietary fibre

Answer 9

• two groups according to their solubility – soluble and insoluble fibre
• occurs naturally in intact plants
• bonds between their monosaccharides cannot be broken down by digestive enzymes=non starch polysaccharides
• contributes little to no energy

Question 10

What is soluble fibre

Answer 10

• disolves in water, forms gel(vicscous), easily digested by bacteria in colon(fermented)
• found in oats, barley, legumes,citrusfruits
• lowers blood cholesterol/glucose lvls=protects against heart disease+diabetes

Question 11

What is insoluble fibre

Answer 11

• does not dissolve in water
• doesn’t from gels
• less readily fermented
• found in whole grains, veg
• promotes bowel movements, alleviates constipiation

Question 12

What is resistant starches

Answer 12

• sum of starch not absorbed in small intestine of healthy individuals.
  -escape digestion and absorption in small intestine
• common in legumes, raw potatoes, unripe banaas

Question 13

How is carbs digested in the mouth

Answer 13

• high fibre food slows eating = flow of saliva
• salivary amylase hydrolyse strach to short poly and to maltose

Question 14

How is carbs digested in stomach

Answer 14

• stomach acid protein digesting enzymes inactivate salivary amylase
• acid breaks down starch
• dietary fibre lingers delaying gastric emptying = feeling of fullness and satiety

Question 15

How is carbs digested in small intestine

Answer 15

• pancreatic amylase enters via pancreatic duct
• breaks down poly into shorter glucose chains and maltose
• at outer membrane of inteSTINAL CELLS specific enzymes break down specific dissacahrides

Question 16

What 3 specific enzymes break down 3 specific dissacahrides in small intestine

Answer 16

• maltase breaks maltose into 2 glucose molecules
• sucrase breaks down sucrose into1 glucose and 1 fructose molecules
• lactase breaks down lactose into 1 glucose and 1 galactose molecule

Question 17

How is carbs digested in large intestine

Answer 17

• only dietary fiber remains in digestive tract
• fiber attracts water =. softening stool for passage in large intestine
• bacteria in gi tract ferment dietary fiber.
• ## process generates water, gas and short chain fatty acids(used for energy in colon)

Question 18

How are carbs ABSORBED in the body

Answer 18

• most nutrient absorption in small intestine
• glucose +galactose traverse the cells lining the small intestine by active transport
• fructose by facilitated diffusion= slowing entry and prods a small rise in BLG lvls
• blood from intestines circulate thu liver - cells take up fructose+galactose
• convert to other compounds(glucose)
• all dissacahrides provide 1 glucose molecule directly
• indirectly, thru conversion of galactose+fructose to glucose

Question 19

When is lactase activity the highest in a humans life

Answer 19

• after birth
• important for infant as milk is only food
• lactase activity declines during childhood to adolescnese

Question 20

What are symptoms of lactose intolerance

Answer 20

• more lactose consumed than available lactase can handle, lactose molecules remain in intestine undigested
• attrachs water= bloating, abdominal discomfort, diarrhoea
• undigested lactose eaten by insteinal bacteria
• bacteria multiplies and prods irritating acid+gas

Question 21

What are causes of lactose intolerance

Answer 21

• lactase activity declines w age
• lactase defiiceny = develops when instential villi damaged by disease/medicines/diarrhoea/malnutrition

Question 22

How to manage lactose intolerance

Answer 22

• increasing consumption of milk products gradually
• mixing dairy w other foods
• spreading dairy intkae thru out the day
• full fat milk
• use of fermented =r heated milk products