ch.4

Question 1

what are the major functions of carbohydrates in cells

Answer 1

short term and intermediate term energy storage

Question 2

what types of energy storage do carbohydrates provide?

Answer 2

short term energy (sugars) and intermediate term energy storage (starch and glycogen)

Question 3

what are the structural components of carbohydrates in cells

Answer 3

cellulose in plant cell walls and chitin in fungal cell walls and arthropod exoskeletons

Question 4

what is the general ratio of the three main atoms in a carbohydrate

Answer 4

1:2:1 Carbon:hydrogen: oxygen

Question 5

what is the molecular formula pattern for monsaccharides

Answer 5

molecular formulas that are multiples of CH2O

Question 6

what are the most common types of monosaccharides

Answer 6

trioses, pentoses and hexoses

Question 7

what are the structural isomers of glycose, galactose and fructose

Answer 7

they all have the same molecular formula of C6H12O6

Question 8

how is a disaccharide fromed

Answer 8

when a dehydration reaction joins two monosaccharides

Question 9

what is an oligosaccharide

Answer 9

small sugar polymers that consist of 2 to 6 monosaccharide units

Question 10

what are glycoconjugates

Answer 10

glycoproteins and glycolipids

Question 11

what defines a polysaccharides

Answer 11

composed of a few thousand monosaccharides linked together by dehydration synthesis

Question 12

why do polysaccharides differ in their properties

Answer 12

they are composed of different isomers and their units may be arranged differently

Question 13

what types of bonds provide high chemical energy in monosaccharides

Answer 13

glycosidic bonds

Question 14

which three monosaccharides can mammals metabolize

Answer 14

glucose, fructose and galactose

Question 15

what is the most common monosaccharide

Answer 15

glucose

Question 16

how do open chain forms of glucose and fructose behave in solution

Answer 16

they form ring structures in solution

Question 17

what is a pyranose ring

Answer 17

a ring structure formed when the C1 aldehyde reacts with the C5 hydroxyl group of glucose

Question 18

what are the two isomeric forms of glucose

Answer 18

alpha and beta glucose

Question 19

how do alpha and beta glucose differ from each other

Answer 19

in the orientation of the OH group at C1

Question 20

what is the role of glucose in biology

Answer 20

product of photosynthesis and used as an energy source in most organisms

Question 21

what distinguishes aldose from ketose monosaccharides

Answer 21

aldose has the carbonyl sugar at the end of the hydrocarbon chain, while ketose has it in the middle

Question 22

what is the smallest sugar and how many carbons does it have

Answer 22

triose, which has 3 carbons

Question 23

what sugar is found in DNA

Answer 23

pentose (ribose) which has 5 carbons

Question 24

why do monosaccharides have isomers

Answer 24

the polymerization of polysaccharides

Question 25

what is a glycosidic linkage

Answer 25

a covalent bond between two monosaccharides

Question 26

how can glycosidic linkages vary

Answer 26

in alpha linkage - OH group on the same side in beta linkage - OH group on opposite sides

Question 27

what is the effect of alpha linkage in carbohydrates

Answer 27

it can be metabolized and used as an energy source

Question 28

what is the effect of Beta linkage in carbohydrates

Answer 28

it cannot be digested by most eukaryotes

Question 29

how is blood glucose maintained in the body

Answer 29

regulated by insulin and glucagon produced by the pancreas

Question 30

what is the role of insulin in blood glucose regulation

Answer 30

insulin decreases blood glucose by promoting glucose transport into cells

Question 31

how does glucagon affect blood glucose levels

Answer 31

glucagon increases blood glucose by stimulating the conversion of glycogen to glucose

Question 32

what happens to glucose levels after a meal

Answer 32

intestines absorb glucose increasing glucose levels, prompting the pancreas to secrete insulin

Question 33

what occurs when blood glucose is low between meals

Answer 33

the pancreas secretes glucagon, leading to the breakdown of glycogen to glucose

Question 34

what causes diabtetes mellitus

Answer 34

it is caused by a deficiency of insulin (type 1) or a decreased response to insulin in target tissues (type 2)

Question 35

what are the symptoms of type 1 diabetes

Answer 35

increased glucose levels in the bloodstream leading to insufficient glucose for cells

Question 36

what characterizes type 2 diabetes

Answer 36

insulin receptors become desensitized due to excessive glucose consumption

Question 37

what causes lactose intolerance

Answer 37

a drop in lactase production leading to digestive issues

Question 38

what causes flatulence from eating legumes

Answer 38

the human stomach does not produce the enzyme needed to breakdown oligosaccharides in beans

Question 39

what are the two functional classes of polysaccharides

Answer 39

energy polysaccharides (starch, glycogen) and structural polysaccharides (cellulose, chitin)

Question 40

what is starch and its role in plants

Answer 40

starch is the main storage molecule in plants and can be hydrolyzed into maltose by amylase

Question 41

what is glycogen and its role in animals

Answer 41

glycogen is a branched polysaccharide that serves as the storage polysaccharide of animals

Question 42

how does glycogen differ from starch

Answer 42

glycogen has a higher degree of branching than starch aiding in solubility

Question 43

what is cellulose and its structure

Answer 43

cellulose is formed by Beta glucose molecules linked by Beta -1-4 linkages creating unbranched chains

Question 44

why cant humans digest cellulose

Answer 44

they lack the enzyme to break the bonds between cellulose molecules

Question 45

how do termites and cattle digest cellulose

Answer 45

termites rely on bacteria that release cellulase while cattle digest cellulose inside bacterial cell walls

Question 46

what is chitin and where is it found

Answer 46

an unbranched polysaccharide found in the exoskeleton of arthropods and in fungal cell walls

Question 47

what is peptidoglycan and its role in bacteria

Answer 47

it is found in bacterial cell walls with varying thickness in gram-positive and gram-negative bacteria

Question 48

how does penicillin affect bacteria

Answer 48

it interferes with peptidoglycan synthesis, killing gram positive bacteria

Question 49

what is dietary and its importance

Answer 49

includes cellulose which aids digestion but is not broken down into monosaccharides

Question 50

how does fiber affect feces

Answer 50

fiber adds bulk and absorbs water making feces larger and softer

Question 51

what are the health benefits of dietary fiber

Answer 51

it reduces pressure for defecation lower cholesterol and slows the rate of carbohydrate absorption

Question 52

what is the role of glycoproteins

Answer 52

help to determine blood types

Question 53

what glycosidic linkage cannot be digested by most eukaryotes

Answer 53

b-linkage

Question 54

what are glycosidic bonds

Answer 54

chemical bonds that join a carbohydrate molecule to another group

Question 55

what is the position of the hydroxyl group in alpha linkages

Answer 55

the hydroxyl group on the anomeric carbon is positioned below the plane of the ring

Question 56

what type of structure do alpha linkages result in

Answer 56

bent or kinked structure

Question 57

which molecules commonly contain alpha linkages

Answer 57

starch (amylose and amylopectin)

Question 58

what is the position of the hydroxyl group in beta linkages

Answer 58

the hydroxyl group on the anomeric carbon is positioned above the plane of the ring

Question 59

what type of structures do beta linkages result in

Answer 59

more linear or extended structure

Question 60

which molecules commonly contain beta linkages

Answer 60

cellulose and chitin