L.1 - carbs

Question 1

What are carbs composed of?

Answer 1

• carbon, hydrogen, and oxygen in a 1:2:1 ratio

Question 2

What does carbohydrate mean?

Answer 2

Hydrate (water of) carbon

Question 3

Name some types of carbs

Answer 3

• sugars
• starches
• cellulose
• glycogen
• chitin

Question 4

What purpose does sugar, starch, cellulose, and chitin do for the cell?

Answer 4

• sugar and starch = energy source of cell
• cellulose and chitin = structural components of cell

Question 5

Example of a monosaccharide, disaccharide, and polysaccharide?

Answer 5

• mono: glucose
• disacc: sucrose
• poly: glycogen or starch

Question 6

What is the most abundant monosaccharide?

Answer 6

Glucose

Question 7

What disease is a breakdown of the mechanism that have revolved to keep glucose at a constant level in blood?

Answer 7

• diabetes

Question 8

What bond joins sugars together?

Answer 8

• glucosidic bonds (these bonds can join sugars together and create polymers of di and polysaccharides)

Question 9

What are the common disaccharides?

Answer 9

• sucrose
• lactose
• maltose

Question 10

What 2 monosaccharides make up sucrose

Answer 10

• glucose-a(1-2)- fructose

Question 11

What 2 monosaccharides make up lactose?

Answer 11

• galactose-b(1-4)-glucose

Question 12

What 2 monosaccharides make up maltose?

Answer 12

• glucose-a(1-4)-glucose

Question 13

Distinguish between alpha and beta glucose.

Answer 13

• alpha glucose have both ‘OH’ on the bottom whereas beta glucose has one ‘OH’ on the top and one ‘OH’ on the bottom

Question 14

What is needed to breakdown disaccharides?

Answer 14

• enzymes. If no enzymes, we can’t break down the sugar and we can’t digest it and this can lead to stomach problems

Question 15

What enzyme hydrolyses/breakdown sucrose?

Answer 15

• invertase (breaks down to glucose & fructose)

Question 16

What enzyme hydrolyses/breakdown maltose?

Answer 16

• maltase

Question 17

What enzyme hydrolyses/breakdown lactose?

Answer 17

• lactase (human)
• b-galactosidase (bacteria)

Question 18

How can you tell you have lactose intolerance?

Answer 18

• nausea pain
• cramps
• diarrhoea

Question 19

Normal lactose digestion Vs lactose intolerant.

Answer 19

normal: lactose —> lactase —> glucose & galactose

not normal: lactose —> no lactase —> bacterial fermentation —> acid & gas

Irritation caused then

Question 20

What is the most abundant carb in nature?

Answer 20

Polysaccharides

Question 21

Examples of polysaccharides?

Answer 21

• starch, glycogen, cellulose, chitin

Question 22

What are polysaccharides?

Answer 22

• thousands of monosaccharides joined together by glycosidic linages (usually glucose)

Question 23

What will turn polysaccharide into monosaccharides in your body?

Answer 23

• enzymatic or acid hydrolysis will release monosaccharides

Question 24

What chains can polysaccharides appear in?

Answer 24

• long single chain
• or branded chain

Question 25

What is a-amylose?

Answer 25

- a long unbranded chain of glucose units linked by alpha (1-4) bonds and has Mr ~ 2000 - 500,000 daltons

Question 26

Is a-amylose soluble?

Answer 26

Not really water soluble but it forms hydrated micelles and in the micelles the polymer forms a helical coil

Question 27

What is amylopectin?

Answer 27

- highly branded polymer that has a length of 24-30 glucose molecules depending on the species Backbone linkage = a(1-4) Branch points = a(1-6)

Question 28

What are amyloplasts ?

Answer 28

- starch granules - constantly built and broken down by plants so they can have energy

Question 29

What enzyme hydrolysis/breaks down starch?

Answer 29

- a-amylase enzyme

Question 30

Where is a-amylase enzyme found?

Answer 30

- saliva and pancreatic justices and this enzyme is important for digested of starch

Question 31

What is another hydrolysis of starch other than a-amylase? Where is it found?

Answer 31

- b-amylase enzyme - found in malt

Question 32

What degrades a-amylose? What can this thing also degrade?

Answer 32

- a and b-amylase They can also degrade amylopectin but cannot break down -(1-6) bonds The products of this breakdown is dextrins (short chains) but the ultimate product is a limit dextrin A debranching enzyme a(1-6) glucosidase is needed for complete refraction

Question 33

What makes up 50% of carbon cpds in plants?

Answer 33

Cellulose

Question 34

What is cellulose?

Answer 34

- a structural carb Wood = 50% cellulose Cotton = 90% cellulose The cell walls of plants are cellulose

Question 35

What are bonds between the glucose units in cellulose?

Answer 35

Beta 1-4 glycosidic linkages

Question 36

Do we have the enzymes necessary to break down cellulose?

Answer 36

- NO!! - cellulose only provides a roughage in the diet (can’t digest but helps w digestion)

Question 37

What is the structural carb found in animals?

Answer 37

- chitin

Question 38

What forms the external skeleton of insects, crayfish, and other arthropods?

Answer 38

Chitin

Question 39

What is the main component in the cell wall of fungi?

Answer 39

- chitin

Question 40

What are glycoproteins? What does it secrete?

Answer 40

- integral membrane proteins - it secretes proteins - antibodies

Question 41

What linkages of glycoprotein?

Answer 41

- contains oligosaccharides in glycosidic linkage to serine, threonine, or asparagine

Question 42

What occurs as intermediates in energy yielding metabolism?

Answer 42

- phosphorylation sugars -example: glucose-6-phosphate (glycolysis)

Question 43

What does phosphorylation do?

Answer 43

- makes sugars an ionic and allows some of them to participate in glucosidic bonding as reactive intermediates