Carbohydrates Flashcards
may be defined as alcohol or aldehyde derivatives of polyhydroxy alcohols or as compounds that yield these derivatives on hydrolysis
carbohydrates
they are the most abundant molecules on earth produced by photosynthesis
carbohydrates
it means “containing several alcohol group”
polyhydroxy
what are the main sources of energy in the body
carbohydrates
__________ and __________ are almost wholly dependent on carbohydrates as the energy source
brain cells and RBCs
storage form of energy
starch and glycogen
excess carbohydrate is converted to __________
fat
what are the components of cell membranes and plasma membranes
glycoproteins and glycolipids
what is the structural basis of many organisms: cellulose of plants; exoskeleton of insects, cell wall of microorganisms
carbohydrates
molecules having only one actual or potential sugar group
monosaccharides
when two monosaccharides are combined together with elimination of a water molecule (dehydration)
disaccharide
they are commonly known as oligosaccharides
trisaccharides (3), tetrasaccharides (4), pentasaccharides (5), and so on
when more than 10 sugar units are combined
polysaccharides
sugars having aldehyde group
aldoses
sugars with keto group
ketoses
compounds having same molecular formula, but different in spatial configuration
stereoisomers
one of two stereoisomers that are mirror images of each other that are non-superposable (not identical)
enantiomers
they are class of stereoisomers that are non-superposable, non-mirror images of one another
epimers
when the OH group is on the right
D-Glucose
dextrorotatory
when the OH group is on the left
L-Glucose
levorotatory
are naturally occuring sugars
D-sugars
used to increase a person’s blood sugar
D-glucose or dextrose
when the OH groups are at the top
D-mannose
when the OH groups are at the bottom
D-galactose
what is the general formula of monosaccharides
Cn(H2O)n
monosaccharides are the simplest __________
simplest carbohydrates
they are aldehydes or ketones with two or more hydroxyl groups
monosaccharides
important fuel molecules as well as building blocks for nucleic acids
monosaccharides
what are the functions of monosaccharides within cells
used to produce and store energy
used to form long fibers
oxygen will bind to a hydrogen
Hydroxyl group (OH group)
one of the carbons in the chain will form a double bond with an oxygen
carbonyl group
if this carbonyl occurs at the end of the chain
aldose family
if the carboxyl group is in the middle of the chain
ketose family
from Greek word for sweet wine; grape sugar, blood sugar, dextrose
glucose
greek word for milk-‘galact’, found as a component of lactose in milk
galactose
latin word for fruit-‘fructus’, also known as levulose, found in fruits and honey; sweetest sugar
fructose
__________ and __________ are found in the backbone structure of RNA and DNA, respectively
ribose and deoxyribose
most predominant sugar in human body
it is the major source of energy
glucose
plants store these long chains of glucose as __________, which can be disassembled and used as energy later
starch
animals store chains of glucose in the __________ __________, which can store a lot of energy
polysaccharide glycogen
is converted to glucose in liver and then utilized as a fuel
galactose
a constituent of lactose (milk sugar)
aldose
it is naturally produced by most mammals, allowing mammals to use __________ in milk to give energy to their offspring
galactose
fruit sugar - naturally in abundance in fruits
fructose
__________ has a unique sweetness, texture, rate of digestion, and degree of absorption that is different from glucose
fructose
what is the chemical formula of disaccharides
C12H22O11
disaccharides are formed through __________ reactions in which a total of one water molecule is removed from the two monosaccharides
dehydration
glucose + fructose
sweetening agent known as cane sugar
sucrose
glucose + galactose
sugar present in milk
most mammals can only digest __________ as infants, and lose this ability as they mature
lactose
product of anaerobic metabolism
lactate or lactic acid
glucose + glucose
known as malt sugar
component of beer, starchy foods like cereal, pasta, and potatoes, and many sweetened processed foods
maltose
large molecule made of many smaller monosaccharides
also called a glycan
polysaccharide
__________ in which all the monosaccharides are the same
homoglycan
__________ in which the monosaccharides vary
heteroglycan
a straight chain of monosaccharides
linear polysaccharide
a chain that has arms and turns
branched polysaccharide
what are the key functions of polysaccharides
for storage
for structural support
sources: potatoes, tapioca, cereals (rice, wheat), and other food grains
starch
reserve carbohydrate of plant kingdom
composed of amylose which is linear in nature and amylopectin which is highly branched
starch
reserve carbohydrate in animals
it is stored in liver and muscle
glycogen
about 5% of weight of liver is made up by __________
excess carbohydrates are deposited as __________
glycogen
supporting tissues of plants
99% of cotton, 50% of wood and is the most abundant organic material in nature
cellulose
this enzyme is absent in animal and human digestive system, and hence __________ cannot be digested
cellulose
part of large intestine - harbor bacteria
caecum
__________ also digest cellulose with the help of intestinal bacteria
white ants (termites)
it is present in exoskeletons of crustacea and insects
chitin
both cellulose and __________ form long, linear chains
these chains form long fibers, which are deposited outside the cell membrane, which increases hydrogen bonding
chitin
from sea weeds
it contains galactose, glucose, and other sugars
agar
cannot be digested by bacteria and hence used widely as a supporting agent to culture bacterial colonies
agar
it is present in connective tissues, tendons, and synovial fluid
it serves as a lubricant in joint cavities
hyaluronic acid
it is an anticoagulant widely used when taking blood in vitro for clinical studies
heparin
is present in liver, lungs, spleen, and monocytes
heparin
