L3: Carbohydrates

Question 1

What ratio of elements are found in carbohydrates?

Answer 1

1 carbon : 2 hydrogen : 1 oxygen

Question 2

How are carbohydrates formed?

Answer 2

Carbon Dioxide + Water

Carbo = carbon; hydrates = water

Question 3

Where does this process occur in nature?

Answer 3

In plants, carbohydrates are formed through photosynthesis.

Question 4

Where do plants gets the energy to form the bonds in carbohydrates?

Answer 4

UV energy. It is locked in C-H bonds

Question 5

How do organisms use carbohydrates?

Answer 5

Energy. Body transports energy in the form of complex carbohydrates and then hydrolyses the molecules to unlock the energy in the bonds.

Question 6

What are three functions of carbohydrates?

Answer 6

1. Rapid energy for cellular reactions
2. Molecular structures (e.g. DNA sugar-phosphate backbone)
3. Cell surface markers (blood group markers)

Question 7

What are the simplest carbohydrates called?

Answer 7

Monosaccharides

Question 8

What is the suffix when naming monosaccharides?

Answer 8

-ose

Question 9

How many carbon atoms can a monosaccharide have?

Answer 9

3-10

Question 10

What is pentose?

Answer 10

A monosaccharide with 5 carbon atoms

Question 11

What would you name a monosaccharide with 4 carbon atoms?

Answer 11

Tetrose

Question 12

Which functional groups are found in monosaccharides?

Answer 12

Hydroxyl, aldehyde, and ketone

Question 13

What do you name a monosaccharide that has 5 carbons and an aldehyde group?

Answer 13

Aldopentose

Question 14

Is glucose an aldose or a ketose?

Answer 14

Aldose

Question 15

Is fructose an aldose or a ketose?

Answer 15

Ketose

Question 16

What is a deoxy- monosaccharide?

Answer 16

Where a hydroxyl group is replaced by H. Include the carbon number that has been deoxylated. e.g. 2-deoxy-ribose

Question 17

In stereoisomerism, which of the following are the same and which are different?

• Chemical formula
• Bond types and orders
• Spatial arrangements
• Biological functions

Answer 17

Same:

• Chemical formula
• Bond types and orders

Different:

• Spatial arrangements
• Biological functions

Question 18

What is a chiral carbon?

Answer 18

A carbon with 4 different things attached to it

Question 19

True or false: monosaccharides can exist in cyclic structures

Answer 19

True

Question 20

How many C-H bonds are found in glucose?

Answer 20

7

Question 21

How many C-H bonds are found in fructose?

Answer 21

7

Question 22

After cyclisation of fructose, what type of ring is formed?

Answer 22

Furan - 4 carbons, 1 oxygen. Other carbons are found on branches

Question 23

What is a disaccharide?

Answer 23

Two monosaccharides linked together

Question 24

How do you form a disaccharide?

Answer 24

Dehydration synthesis

Question 25

What biological molecules assist the formation of disaccharides?

Answer 25

Enzymes

Question 26

What type of bond joins two monosaccharides?

Answer 26

Glycosidic link

Question 27

What is the primary function of a disaccharide?

Answer 27

Nutritional source of monosaccharides

Question 28

What are the monosaccharides in Maltose?

Answer 28

Glucose + Glucose | alpha 1,4 glycosidic link

Question 29

What are the monosaccharides in Lactose?

Answer 29

Glucose + Galactose | beta 1,4 glycosidic link

Question 30

What are the monosaccharides in Sucrose?

Answer 30

Glucose + Fructose | alpha 1,2 glycosidic link

Question 31

How are disaccharides broken down?

Answer 31

Hydrolysis with enzyme assistance

Question 32

Sucrose, maltose, and lactose are examples of what?

Answer 32

Disaccharide

Question 33

Why are monosaccharides sometimes converted to oligo- and poly-saccharides?

Answer 33

To make them insoluble so they can be stored, be used in structures, or take part in cellular processes

Question 34

What is a glycoprotein?

Answer 34

A protein that has oligosaccharide chains (glycan) attached covalently

Question 35

What is a glycolipid?

Answer 35

A lipid that has oligosaccharide chains (glycans) attached covalently

Question 36

What glycosylated molecules are important in immune recognition?

Answer 36

Glycoproteins in the cell membrane

Question 37

What are mucins?

Answer 37

Secreted glycoproteins that form either components of mucous or saliva

Question 38

What are GAGs?

Answer 38

Jokes. Jk, they are glycosaminoglycans. These are long, unbranched chains of repeating disaccharide units.

Question 39

What are the two base components of glycosaminoglycans?

Answer 39

Amino sugars and uronic acids

Question 40

True or false: GAGs are hydrophobic.

Answer 40

False. They are hydrophilic (-ve charge)

Question 41

True or false: GAGs form gels.

Answer 41

True.

Question 42

True or false: GAGs have a high viscosity and low compressibility.

Answer 42

True.

Question 43

True or false: GAGs are good lubricants.

Answer 43

True.

Question 44

True or false: GAGs add structural integrity.

Answer 44

True.

Question 45

True or false: GAGs that are attached to proteins are known as mucopolysaccharides.

Answer 45

False. Mucopolysaccharides are NOT attached to proteins.

Question 46

What do you call GAGs that are attached to proteins?

Answer 46

Proteoglycans

Question 47

Chondroitin is an example of what molecule? What are its functions?

Answer 47

Proteoglycan - cartilage, heart valves and bones

Question 48

Hyaluronic Acid is an example of what molecule? What are its functions?

Answer 48

Mucopolysaccharide - lubricant and shock absorber in synovial fluid and vitreous humour of the eye

Question 49

What kind of molecule is usually associated with phospholipids on the outer surface of the cell membrane?

Answer 49

Glycolipids

Question 50

When associated with phospholipids, what are the common functions of glycolipids?

Answer 50

Recognition signals, attachment factors, membrane stabilisers

Question 51

Ceramide, sphingomyelin, cerebrosides, and gangliosides are all examples of what type of molecule?

Answer 51

Sphingolipids, which are a subtype of glycolipid

Question 52

True or false: The most common type of starch is Amylopectin

Answer 52

True. It accounts for 70-80% of starch molecules and is a brush shape (like a T, where the lines are helical)

Question 53

True or false: Amylose assumes a straight, unbranched shape.

Answer 53

False. It is a helical coil shape, and it accounts for 20-30% of starch molecules

Question 54

True or false: Starch is the main source of carbohydrate in the diet.

Answer 54

True. It is found in the amyloplasts and chloroplasts of plant cells

Question 55

True or false: Starch is digested by amylase and lactase.

Answer 55

False. It is digested by amylase and maltase

Question 56

True or false: Starch is the main storage polymer of animals.

Answer 56

False. It is the main storage polymer of plants.

Question 57

True or false: Glycogen is the main storage polymer of animals.

Answer 57

True. It is stored in the liver and muscle cells.

Question 58

True or false: Glycogen branches more frequently than starch.

Answer 58

True. With branch points occurring every 8 to 12 residues.

Question 59

What is the difference between alpha and beta glucose?

Answer 59

The position of the H and OH on the first carbon determine whether it is alpha or beta. In a-glucose, the H is up top. In b-glucose, the H is down.