1.4 Carbs and Lipids Flashcards
Carbohydrate definition
a biomolecule that consists of carbon, oxygen, and hydrogen
Function of carbohydrates
energy source, building material, cell communication
Monosaccharide definition
the simplest form of carbohydrate, consisting of a single sugar unit; a building block for more complex carbohydrates
Although all monosaccharides can occur in a _______ form, when formed in water, monosaccharides with five or more carbon atoms fold back on themselves to form a ____
linear; ring
When glucose forms a ring, there are ____ possible arrangements of the –OH group,
which is bound to the carbon at position 1: ________and ___________
two; a-glucose and b-glucose
Isomer definition
A molecule that has the same chemical formula as another, but a different arrangement of atoms
The different arrangements of the –OH group on glucose can give chemicals different ___________.
properties
Glucose, fructose, and galactose are _________ of each other.
isomers
Sugars typically have many _____ functional groups attached to them. This makes
them very _____ and means that small sugars are ______ soluble in water.
polar; hydrophilic; highly
True or false:
Monosaccharides are the sweetest.
True
As the number of monosaccharide units
that are linked together increases, the sweetness ________.
decreases
Disaccharide definition
A carbohydrate molecule that is made from two monosaccharide units
Glycosidic bond definition
a bond between two monosaccharides
The chemical shorthand for representing a
glycosidic bond between a 1-carbon and a 4-carbon is _______.
1–> 4
Disaccharide carbohydrate molecules contain the same functional groups that make monosaccharides _________. Therefore, they are easily ________ in water.
hydrophilic; dissolved
Complex carbohydrate definition
a molecule that is composed of hundreds to thousands of monosaccharides linked together
Some complex carbohydrates are important for ______ storage in cells, while others are essential for ______ support.
energy; structural
Polysaccharide molecule definition
A polysaccharide molecule is a chain of monosaccharides with many subunits joined
by glycosidic linkages
A polysaccharide is a macromolecule,
which is a very large molecule assembled by the _____ linkage of smaller subunit _______.
covalent; molecules
The dehydration synthesis reactions that assemble polysaccharides are examples of __________.
polymerization
Polymerization definition
Polymerization is the process in which identical or variable subunits, called monomers, link together in a long chain to form a larger
molecule (polymer).
Monomer definition
a small molecule that can bind
chemically to other molecules
Polymer definition
a large molecule that is formed when monomers link together chemically in a chain
True or false:
DNA is a type of polysaccharide.
False
DNA is a type of polymer
Polysaccharides are very polar and therefore very _______. However, since polysaccharides are such huge molecules, they attract water but cannot _____.
hydrophilic; dissolve
Monosaccharide structure
chain, a-ring or b-ring
Monosaccharide function
energy source, building blocks
Monosaccharide example
glucose, ribose and deoxyribose
Disaccharide structure
2 monomer subunits, with a or b linkage
Disaccharide function
energy source
Disaccharide example
sucrose, maltose and lactose
Polysaccharide structure
very long chain or branching chain with a or b linkages
Polysaccharide function
energy storage, structural support, and cell to cell communication
Polysaccharide example
starch and cellulose
Lipid definition
a non-polar compound made mostly of carbon and hydrogen
True or false:
Lipids are smaller than complex carbohydrates, so they are not considered to be macromolecules.
True
Since lipids are generally _________, they do not dissolve in water. Their insolubility in water contributes to their ability to form cell ________-.
non-polar; membranes
Lipid function
stored by cells to be used as an energy source, serve as hormones that regulate cellular activities and used as vitamins.
Lipids in living organisms fall into 5 main categories:
fatty acids, fats, phospholipids, steroids, and waxes
The structural backbone of most lipids is derived from ________ _______.
fatty acids
Fatty acid definition
A fatty acid consists of a single hydrocarbon chain with a carboxyl functional group (-COOH) at one end
As their chain length increases, fatty acids become progressively _______ water soluble.
less
If the hydrocarbon chain of a fatty acid binds the maximum possible number of hydrogen atoms, and if all the carbons are linked to each other with single bonds, the fatty acid is said to be __________
saturated
If there are double bonds in the fatty
acid chain, then it is said to be ________. This means that the carbon chain has the potential to form more bonds with ________.
unsaturated; hydrogen
Fatty acids with one double bond are ___________, and those with more than one double bond are
____________.
monounsaturated; polyunsaturated
The presence of a double bond in an unsaturated fatty acid creates a kink in the molecule, which causes it to _______.
bend
A fat is a lipid that is made from two types of molecules:
fatty acid and a glycerol molecule.
Triglyceride definition
a fat; three fatty acid chains linked to a glycerol molecule
Saturated fat definition
a lipid that is composed of saturated fatty acids with single bonds in their hydrocarbon chain
Unsaturated fat definition
a lipid that is composed of unsaturated fatty acids with double bonds in their hydrocarbon chain
Phospholipid definition
a lipid that consists of two fatty acids and a phosphate group bound to glycerol
Like individual fatty acids, triglycerides generally become less fluid as the length of their fatty acid chain ________.
increases
Warm-blooded mammals and birds are the exception in having mostly saturated fats,
but these fats are _______ because of relatively ______ body temperature.
liquids; high
Triglycerides function widely as stored _______.
energy
Phospholipids are the primary lipids of cell ___________.
membranes
In the most phospholipids, glycerol forms the backbone of the molecules.
Only 2 of its binding sites, however, link to _____ _____.
The third site links to a charged __________
group, which often binds to another polar or charged unit.
fatty acids; phosphate
A phospholipid contains two hydrophobic fatty acids at one end, attached to a hydrophilic polar
group, often called the _____ group
head
Molecules that contain both hydrophobic and hydrophilic regions are called __________ molecules.
amphipathic
The head of an amphipathic molecule is the polar and _________ region.
hydrophilic
The tail is the _______ lipid, which is composed of a _______ chain.
hydrophobic; carbon
The hydrophilic end of a phospholipid faces ________ toward water, and the hydrophobic fatty acid tails face _______ toward each other
outward; inward
Steroid definition
a lipid that is composed of four carbon rings
The most abundant steroids, the _______, have a
single polar ___ group at one end of the ring framework and a complex, non-polar
__________ chain at the other end.
sterols; –OH; hydrocarbon
Although sterols are almost completely
________, the single hydroxyl group gives one end a slightly polar, _______ character.
hydrophobic; hydrophilic
A high concentration of cholesterol (steroid) in the bloodstream and a diet rich in saturated fats have been linked to the development of ____________, a condition in which fat deposits, or plaques, form on the inner lining of blood vessels.
atherosclerosis
Wax definition
Waxes are large lipid molecules that are made of long fatty acid chains linked to alco-
hols or carbon rings.
Waxes are ________, extremely ________, and soft solids over a wide range of temperatures.
hydrophobic; non-polar
Fatty acid structure
carboxyl group linked to a hydrocarbon chain
Fatty acid function
cellular functions and energy storage
Fatty acid example
stearic acid
Fat structure
3 fatty acid chains linked to glycerol
Fat function
energy storage and insulation
Fat example
butter and olive oil
Phospholipid structure
2 fatty acid chains and 1 phosphate group linked to glycerol
Phospholipid function
cell membrane
Phospholipid example
lipid bilayer
Steroid structure
4 carbon rings
Steriod function
hormone signalling, cell response to the environment and growth
Steriod examples
testosterone and cholesterol
Wax structure
long fatty acid chains linked to alcohol or carbon rings
Wax function
water resistance and protection
Wax examples
wax coating on fruits, leaves and stems
Phospholipids are the main component of all _______ ________.
They are formed from a glycerol molecule, two fatty acids, and an _____ phosphate-containing group.
plasma membranes; ionic
Waxes are long fatty acid chains linked to alcohol or _____ structures. They function primarily as ___________ compounds.
ring; waterproofing
Relate the chemical structure of carbohydrates to their physical properties and uses.
Carbohydrates are hydrocarbons that are dependent on their length, structure, and functional groups to determine their solubility.
They are useful sources of structural materials and energy for living organisms.
Humans use carbohydrates in many ways. How do humans use monosaccharides, disaccharides, and polysaccharides.
Monosaccharides are the primary fuel source for human cells. They are broken down during energy production or polymerized to form disaccharide or polysaccharide chains.
Disaccharides are mainly food in human food sources and lactose is a disaccharide found in milk.
Polysaccharides are used for structural purposes and for glucose storage.
Compare the polarity of carbohydrates and lipids. How does their polarity relate to their physical properties?
Carbohydrates are polar and lipids are non-polar.
Polar carbohydrates are very hydrophilic and dissolve in water if they are small enough.
Lipids are hydrophobic and insoluble in water. These properties make lipids useful in cell membranes and as water proofing molecules.
Why are most polysaccharides insoluble in water?
Most polysaccharides are insoluble in water because they are too large to dissolve.
Distinguish between a fatty acid and a fat.
A fatty acid is a long hydrocarbon chain with a carboxyl group on its end. Fat is composed of three fatty acid chains attached to a glycerol molecule.
What happens to the acidic properties of a fatty acid when a fat is formed?
Acidic properties of fatty acids come from carboxylic acid functional groups and this quality does not exist in fat.
Why are steroids important, even though they tend to have a bad reputation?
Steroids are important for normal growth, maintenance of the plasma membrane, hormonal signalling and development, even though some athletes misuse them.
monosaccharides
simplest carbohydrate, consists of a single sugar molecule
What is an isomer and give an example
Isomer – a molecule that has the same composition
but different arrangement of atoms
Ex. Glucose can have 2 possible OH group arrangements called α-glucose and β-glucose
What makes sugars (monosaccharides) hydrophilic?
have many POLAR FUNCTIONAL
GROUPS attached to them
This makes sugars hydrophilic and thus highly soluble in water
disaccharide
a carbohydrate molecule made
up of TWO monosaccharides
Monosaccharides are joined together by ________ and the resulting bonds are called _______
dehydration synthesis; glycosidic bonds
glycosidic bond
a bond between two
monosaccharides
Polysaccharide
molecule that contains more than 2 linked monosaccharides
Often contain hundreds to
thousands of monosaccharides
polymerization
the linking of smaller subunits to create a larger molecule
monomer
a single subunit
polymer
a large molecule that is
formed when monomers link together
cellulose
a polymer of glucose
the most abundant organic molecule on earth
provides structural support for plants
If polysaccharides are hydrophilic, why don’t they dissolve in water?
Polysaccharides are hydrophilic but are too large to dissolve in water
monosaccharide structure
carbon chain or ring
disaccharide structure
two monomers linked by glycosidic bond
polysaccharide structure
branched or unbranched chains of monomers
lipid
a non-polar compound that is made mostly of carbon and hydrogen (hydrophobic)
fatty acid
a molecule that consists of a carboxyl group and a hydrocarbon chain
fats
a combination of fatty
acids and glycerol molecules
triglyceride
a fat that contains three fatty acids linked to a glycerol molecule
Fatty acids are linked to a
______ molecule via ______________
glycerol; dehydration
synthesis
saturated fats
lipids composed of saturated fatty acids with single bonds in their hydrocarbon chain
unsaturated fats
lipids composed of unsaturated fatty acids with double bonds in their hydrocarbon chain
phospholipid
a lipid that contains two fatty acids and a phosphate group bound to a glycerol
phospholipid bilayer
a double layered membrane
around cells/organelles
steroid
a lipid that is composed of 4 carbon rings
Used to make some hormones
Can be modified into vitamins
wax
a lipid that is formed when long fatty acid chains are joined to alcohols or carbon rings
Form flexible, waterproof coatings on plant/animal parts
May also be used to build structures such as honeycombs
Polysaccharide molecule
A chain of monosaccraides with many subunits joined by GLYCOSIDIC LINKAGES
