Carbohydrates

Question 1

What are Carbohydrates components of?

Answer 1

• Water and Carbon

Question 2

What molecules are carbohydrates made of?

Answer 2

• Hydrogen, Oxygen + Carbon

- Ratio 1:2:1 - CH20

Question 3

Read

Answer 3

CARBOHYDRATES ARE

• Main source of Energy for all living organisms –Glucose.
• Serve as structural components such as DNA – Ribose, Cell wall made up of cellulose.
• The simplest carbohydrates are sugar units also called saccharides.

Question 4

What are the 4 types of Carbohydrates?

Answer 4

• Monosaccharides (1 saccharide)
• Disaccharides (2 saccharide)
• Oligosaccharide (3 or more saccharides)
• Polysaccharide ( >10 saccharides)

Question 5

What are the simplest carbohydrates/ sugar units also called

Answer 5

• Saccharides also called sugar units.

Question 6

What are Monosaccharides?

give examples

Answer 6

• Simplest carbohydrates + can’t be hydrolysed to
  smaller carbs.
• End in -ose
• E.g. Glucose, Galactose, Fructose

Question 7

What is the functional group of a monosaccharide?

Answer 7

• Carbonyl Group

- Chemically organic functional group composed of a carbon atom double-bonded to an oxygen atom → [C=O]

Question 8

What are the 2 Carbonyl groups for a Monosaccharide?

Answer 8

• Aldehyde ( C=O bonded to at least one Hydrogen) always in C chain.
• Ketone ( C=O bonded to 2 Carbons) always w/in C chain.

Question 9

What do Aldehyde’s and Ketones turn to when they’re monosaccharides.

Answer 9

• Aldoses

- Ketoses

Question 10

Read

Answer 10

• Most common monosaccharide: 3-7 carbons (unbranched)
• No. of C atoms given by prefix: tri-, tetr-, pent-, hex-, hept-
• No. of carbons Generic Name: 3 Triose
  4 Tetroses
  5 Pentoses
  6 Hexoses
  7 Heptoses

Question 11

Read

Answer 11

• A 3C triose sugar with an aldehyde group = aldotriose sugar
• A 4C tetrose sugar with an aldehyde group = aldotetrose sugar
• A 5C pentose sugar with an aldehyde group = aldopentose sugar
• A 6C hexose sugar with an aldehyde group = aldohexose sugar
• A 7C heptose sugar with an aldehyde group = aldohepose sugar
• A 3C triose sugar with an ketone group = ketotriose sugar
• A 4C tetrose sugar with an ketone group = ketotetrose sugar
• A 5C pentose sugar with an ketone group = ketopentose sugar
• A 6C hexose sugar with an ketone group = ketohexase
• A 7C heptose sugar with an ketone group = ketoheptose sugar

Question 12

What are Chiral Centers?

see pics slide 11 +12 + 13 +14

Answer 12

• Chiral centers are tetrahedral atoms (usually C) that have 4 diff substituents.
• Molecules with “n” chiral centers have 2n stereoisomers.
• E.g. Glyceraldehyde: 1 chiral center

Question 13

What are Isomers?

Answer 13

• 2 compounds that have the same molecular formula, but have diff structural formulas.

Question 14

Read

Answer 14

• Ribose & Ribulose are isomers that differ by the location of the carbonyl group (C=O).
• In ribose the C=O belongs to an aldehyde
• In ribulose the C=O belongs to a ketone
• Ribose is classified as an aldose, Ribulose is a ketose
• Similarly Glucose & Fructose are isomers where glucose is an aldose & fructose is a ketose.

Question 15

What is the main source of energy for cells or humans?

Answer 15

• Glucose ( C6 H12 06)

Question 16

Read

Answer 16

• Look at slides 16 - 19

Question 17

How are monosaccharides attached to each other?

Answer 17

• By covalent bonds called Glycosidic bonds by a condensation rxn.

Question 18

Where are Glycosidic bonds formed?

Answer 18

• Between C 1 of a monosaccharide & a hydroxyl (OH) carried by a C atom in a diff monosaccharide molecule.

Question 19

Give an example of a Disaccharide?

Answer 19

• Maltose (2 glucose molecules covalently bind by a glycosidic bond.
• Lactose (Galactose + Glucose)
• Sucrose (Glucose + Fructose)

Question 20

Oligosaccharide example?

Answer 20

• Raffinose

- Stachyose

Question 21

What are Polysaccharides also called?

Answer 21

• Glycans

Question 22

Function of a Polysaccharide?

Answer 22

• Energy storage (glycogen in animal & starch in plant cells)
• Structural support (cellulose in plant cell wall)

Question 23

Examples of Polysaccharides?

Answer 23

• Glycogen
• Starch
• Cellulose
• Chitin

Question 24

Use of monosaccharides in animals?

Answer 24

• Glucose is carried by the blood to transport energy to cells throughout the body.

Question 25

Use of monosaccharide in plants?

Answer 25

• Fructose
  = sweet taste
  = attracts animals
  = disperse seeds

Question 26

Use of disaccharide in animals?

Answer 26

• Glycogen = short-term energy store in liver & in muscles.

Question 27

Use of disaccharide in plants?

Answer 27

• Sucrose – carried by Phloem to transport energy to cells

through the plant.

Question 28

Use of Polysaccharides in animals?

Answer 28

• Glycogen = short-term energy store in liver & in muscles

Question 29

Use of Polysaccharides in plants?

Answer 29

• Cellulose = strong fibers, used to construct plant cell wall.

Question 30

Read

Answer 30

1. Major source of energy which is available immediately as glucose.
2. When excess Carbohydrate is available it can be stored as glycogen in the liver & muscle cells of animals & starch in plants.
3. Forms Structural Tissue in - Plants - cellulose
   - Animals – proteoglycans: teeth, cartilage
   - Bacteria - cell wall
4. Found in the plasma membrane linked to lipids – glycolipids & play a role in structural integrity of the cell.
5. Found in the plasma membrane linked to proteins – glycoproteins & play a role in cell recognition.
6. Ribose sugar is important in the formation of DNA & RNA.
7. Proteins Sparing Action – when Carbohydrates are not sufficient in our body, proteins are broken down to fulfil the requirement of Carbohydrate.
8. Helps prevent Ketosis – in the absence of adequate Carbohydrate, large amounts of ketone bodies are produced in the blood. This increases the blood acidity. In severe cases this can lead to coma/death.
9. Provides Fibre – creates soft bulky stool that moves quickly through the large intestine.