Lecture 4 - Carbohydrates Part 1

Question 1

What are the 3 atoms found in a carbohydrate?

Answer 1

C, H, O

Question 2

What is the main function of carbohydrates in a cell/our body?

Answer 2

primary energy source for metabolic processes

Question 3

What are monosaccharides?

Answer 3

simple sugars
-number of carbon atoms (pentose or hexose)
-defined by type of carbonyl group (aldose or ketose)

Question 4

What are D-glucose and L-glucose?

Answer 4

D-sugars: OH group right of chiral center
L-sugars: OH group left of chiral center

Question 5

What is the natural form of glucose (D or L)?

Answer 5

L-glucose = natural form

Question 6

What is the pyranose form of sugar?

Answer 6

-OH group on 5’ carbon

Question 7

Is the dominating form of D-glucose the open chain form or furanose form?

Answer 7

furanose form = dominant
ring is more thermodynamically stable

Question 8

What kind of sugar is lactose?

Answer 8

disaccharide
galactose + glucose
joined by glycosidic bond

Question 9

What is an anomer?

Answer 9

C1 = anomeric carbon
geometric variation of cyclic sugars
alpha and beta carbons on either side

Question 10

What kind of covalent bond is formed between 2 sugar molecules?

Answer 10

glycosidic bond

Question 11

Which of the 4 major biomolecules contains ribose, nitrogenous base, and a phosphate?

Answer 11

nucleic acids
nucleotide = nitrogenous base glycosidic bond to ribose sugar
nucleotide = nucleoside covalently bound to phosphate group

Question 12

In which important molecule do we find a ribose, nitrogenous base adenine, and 3 phosphate groups attached?

Answer 12

ATP

Question 13

What kind of sugar is glycogen?

Answer 13

polysaccharide
short-term energy storage

Question 14

What are examples of disaccharide?

Answer 14

lactose
sucrose
fructose

Question 15

What is starch and the 2 components it consists of?

Answer 15

starch: polymeric carbohydrate (many glucose units joined by glycosidic bonds)
produced by green plants for energy storage
amylose + amylopectin

Question 16

What is the major function of glycogen?

Answer 16

short term energy storage

Question 17

Where in the body is glycogen primarily stored?

Answer 17

liver and skeletal muscle

Question 18

What are glycosaminoglycans?

Answer 18

structural carbohydrates
mucopolysaccharides - viscous, lubricating properties
part of proteoglycans
negatively charged
repeating 2-sugar unit = uronic sugar + amino sugar

Question 19

What are the functions of GAGs?

Answer 19

regulation of cell growth
proliferation
promotion of adhesion
anticoagulation
repair

Question 20

What is an example of GAG?

Answer 20

keratin sulfate in cornea

Question 21

What is proteoglycan made of?

Answer 21

heavily glycosylated proteins
baseic proteoglycan unit = “core protein” + 1 or more covalently attached GAG
serine = point of attachment
in connective tissue

Question 22

Which proteoglycan is the major PG in the cornea?

Answer 22

keratin sulfate

Question 23

What are glycoproteins?

Answer 23

proteins that have oligosaccharide chains (glycans) bound to polypeptide chain

Question 24

What is glycosylation?

Answer 24

co-trnaslational or posttranslational modification (after peptide chain is made)

Question 25

What are the 2 most common types of glycosylation?

Answer 25

N-glycosylation: sugars attached to nitrogen
O-glycosylation: sugars attached to oxygen

Question 26

What is glypiation?

Answer 26

form of glycosylation resulting in creating a membrane anchor