Chapter 3: Biological Macromolecules Flashcards
What are the four major macromolecules?
Carbohydrates, lipids, proteins and nucleic acids
dehydration synthesis
when monomers combine to create polymers and release water as a byproduct
How is water created in a dehydration synthesis reaction?
The hydrogen of one monomer combines with a hydroxyl group of another monomer
How are monomers bonded in a dehydration synthesis reaction?
When a hydrogen and a hydroxyl group form water, the leftover oxygen creates a covalent bond between the monomers
hydrolysis
when a polymer is broken up into its monomer components
What molecule is needed in a hydrolysis reaction?
Water
How are polymers broken into monomers in hydrolysis?
Each monomer gains hydrogen or a hydroxyl group when water is split
What is the stoichiometric formula for carbohydrates?
(CH2O)n
What does ‘n’ represent in the carbohydrate stoichiometric formula?
The number of carbon atoms in the molecule
What is the ratio of carbon to hydrogen to oxygen in carbohydrates?
1:2:1
What are the three subtypes of carbohydrates?
Monosaccharides, disaccharides and polysaccharides
monosaccharides
simple sugars
What is the suffix for most monosaccharides?
-ose
aldehyde group
functional group where carbonyl group is attached to one hydrogen and another group
aldose
monosaccharide with an aldehyde group
ketone group
functional group where carbonyl group is attached to two carbon groups
ketose
monosaccharide with a ketone group
carbonyl group
a carbon and oxygen atom bound by a double bond
What are the three types of monosaccharides by number of carbon atoms?
Trioses, pentoses and hexoses
asymmetric carbon
carbon that is attached to four other atoms or groups
anomeric carbon
the carbon atom in a carbon ring derived from the carbonyl group
α glucose
glucose where the hydroxyl group is below the anomeric carbon
β glucose
glucose where the hydroxyl group is above the anomeric carbon
How many carbons are in a glucose ring?
Six
How many carbons are in a ribose ring?
Five
How many carbons are in a fructose ring?
Five
How many carbons can a carbon ring have and still be stable?
Five or six
What are two common isomers of glucose?
Galactose and fructose
What is another name for an anomeric carbon?
Carbon 1
disaccharide
two monosaccharides bound together
glycosidic bond
a covalent bond that joins a carbohydrate with another molecule
What bond holds together a disaccharide?
A glycosidic bond
What are the two types of glycosidic bonds when glucose is part of a disaccharide?
An alpha bond and a beta bond
alpha glycosidic bond
glycosidic bond that forms below carbon 1 because the OH group was below carbon 1
beta glycosidic bond
glycosidic bond that forms above carbon 1 because the OH group was above carbon 1
What are three common disaccharides?
Lactose, maltose and sucrose
lactose
disaccharide of glucose and galactose
maltose
disaccharide of two glucose molecules
sucrose
disaccharide of glucose and fructose
amylose
a linear-shaped glucose polymer that is a component of starch
amylopectin
a branched glucose polymer that is a component of starch
What bonds join glucose in starch?
Alpha 1-4 glycosidic bonds and alpha 1-6 glycosidic bonds
alpha 1-4 glycosidic bond
glycosidic bond where the carbon 1 of one monomer is joined to the carbon 4 of another monomer
alpha 1-6 glycosidic bond
glycosidic bond where the carbon 1 of one monomer is joined to the carbon 6 of another monomer
Where are alpha 1-4 glycosidic bonds found in starch?
At linearly joined glucoses
Where are alpha 1-6 glycosidic bonds found in starch?
At the branch points between glucoses
What glycosidic bonds are found in amylose?
Alpha 1-4 glycosidic bonds
What glycosidic bonds are found in amylopectin?
Alpha 1-4 and alpha 1-6 glycosidic bonds
What is the animal equivalent of starch?
Glycogen
glycogen
glucose polymer
What is the general structure of glycogen?
It is highly branched
What is the role of glycogen?
To store energy
cellulose
glucose polymer
What is the role of cellulose?
It makes up most of the cell wall in a plant
What is the most abundant natural polymer?
Cellulose
Which bond joins glucose together in cellulose?
Beta 1-4 glycosidic bonds
How is each glucose arranged in cellulose?
They are alternately flipped
chitin
polysaccharide containing nitrogen
What is the main role of chitin?
As an exoskeleton for arthropods and it is part of the cell wall in fungi
What are the two main parts of a fat molecule?
Glycerol and fatty acids
What is glycerol made up of?
Three carbons, five hydrogens and three hydroxyl groups
How many carbons does a fatty acid have?
Four to thirty-six
What bond joins fatty acids to glycerol?
An ester bond through an oxygen
Where are fatty acids joined to glycerol?
Fatty acids are joined to carbon atoms on the glycerol
Through which process are fatty acids joined to glycerols?
Dehydration synthesis reaction
What are other names for fat?
Triacylglycerols or triglycerides
What is a fat in liquid form called?
Oil
monounsaturated fat
unsaturated fat with only one double bond
polyunsaturated fat
unsaturated fat with more than one double bond
How is hydrogen configured in a cis fat?
Hydrogen atoms are on the same side of the double bond
How is hydrogen configured in a trans fat?
Hydrogen atoms are on opposite sides of the double bond
How are oils artificially turned into trans fats?
Hydrogen gas is bubbled through oil so some cis fats can gain hydrogen and becomes trans fats
essential fatty acids
fatty acids that the body needs but does not synthesise on its own
What are the two essential fatty acids for humans?
Omega-3 and omega-6 fatty acids
Why does omega-3 fatty acid have a ‘3’ in its name?
The third carbon from the hydrocarbon chain’s end is joined to the neighbouring carbon by a double bond
Why does omega-6 fatty acid have a ‘6’ in its name?
The sixth carbon from the hydrocarbon chain’s end is joined to a neighbouring carbon by a double bond
carboxyl group
oxygen is bound to carbon with a double bond and a hydroxyl group is bound to carbon with a single bond
What are the three types of omega-3 fatty acids?
ALA, EPA and DHA omega-3 fatty acids
phospholipid
lipid with two fatty acids and a modified phosphate group
diacylglyercol
lipid with two fatty acids attached
alcohol
any molecule with a hydroxyl group attached to a carbon
sphingosine backbone
more complex alcohol that can serve as a lipid backbone like glycerol
phosphatidate
the precursor to phospholipids
What is phosphatidate composed of?
A diacylglycerol and an unmodified phosphate group
How does phosphatidate become a phospholipid?
An alcohol modifies the phosphate group
Is phosphatidate a phospholipid?
No, it is only a precursor
What are the two main phospholipids that are in the cell membrane?
Phosphatidylcholine and phosphatidylserine
amphipathic
having both a hydrophilic and hydrophobic component
Which part of a phospholipid is hydrophilic?
The phosphate head
Which part of a phospholipid is hydrophobic?
The fatty acid chains
What type of structure do steroids have?
A fused ring structure with a short tail
steroid
a type of lipid with four carbon rings
Why are steroids classified as lipids?
They are hydrophobic and insoluble in water
How many carbon rings do all steroids have?
Four
What is the most common steroid?
Cholesterol
Where is cholesterol synthesised?
In the liver
sterol
steroids with a hydroxyl group
What is the main sterol in animals?
Cholesterol
What is the main sterol in plants?
Phytosterol
substrate
a reactant that binds to an enzyme
What three main actions do enzymes help in?
Breakdown, rearrangement or synthesis reactions
catabolic enzymes
enzymes that breakdown their substrates
anabolic enzymes
enzymes that build more complex molecules from their substrates
catalytic enzymes
enzymes that affect the rate of reaction
hormone
chemical-signalling molecules
Where are hormones secreted?
In endocrine cells
denaturation
modification of protein structure so that it loses its function
What are the two main shapes of proteins?
Globular or fibrous
How many amino acids are there currently?
Twenty
amino acid
monomer of proteins
What are all amino acids composed of?
A central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom and an R group
alpha carbon
carbon atom that directly connected to a functional group
amino group
functional group composed of NH2
What is the pH of a carboxyl group?
Acidic
Why is an amino acid called an amino acid?
An amino acid has a amino group and a carboyxl-acid-group attached
How many essential amino acids are there?
Nine
What determines an amino acid’s properties?
The R group
peptide bond
covalent bond that joins amino acids together
How are peptide bonds formed?
Through a dehydration synthesis reaction
Which two groups in an amino acid form a peptide bond?
The carboxyl group of one amino acid and the amino group of another come together in a dehydration reaction
peptide
two or more linked amino acids
polypeptide
a long chain of amino acids
amino terminal
the free amino group at one end of a polypeptide chain
What is another name for an amino terminal?
N terminal
carboxyl terminal
the free carboxyl group at one end of a polypeptide chain
What is another name for a carboxyl terminal?
C terminal
What is the difference between a polypeptide and a protein?
A polypeptide is a general chain of amino acids whereas a protein is the finalised and functional verson
primary structure
the sequencing structure of amino acids in polypeptide chains
disulphide bond
a bond held together by two sulphurs
How do disulphide bonds form?
Two sulfhydryl groups react in the presence of oxygen in a dehydration reaction
sulfhydryl
A sulphur and hydrogen bonded together
Which amino acid replaces glutamate in a sickle cell hemoglobin?
Valine
Which amino acid is replaced by valine in a sickle cell hemoglobin?
Glutamate
secondary structure
the local folding of polypeptide chains
What are the two most common secondary structures?
The alpha-helix and beta-pleated sheet
How are alpha-helixes and beta-pleated sheets held together?
By hydrogen bonds
How far apart is each hydrogen bond in an alpha-helix?
Hydrogen bonds are located every three to four residues along the chain
How long is every helical turn in an alpha-helix?
3.6 residues
Where are hydrogen bonds formed in alpha-helixes and beta-pleated sheets?
Between the oxygen in the carbonyl group of one amino acid and the hydrogen in the amino group of another
Where are the R groups in alpha-helixes?
They protrude outward from the helix
Where are the R groups in beta-pleated sheets?
They extend above and below the pleated sheets
What are the two configurations of beta-pleated sheets?
Parallel and antiparallel
tertiary structure
the three-dimensional folding structure of a polypeptide chain
How is a protein’s tertiary structure determined?
By the interactions among the R groups
How are R groups arranged in a protein’s tertiary structure?
Nonpolar hydrophobic R groups tend to lie on the inside of the protein, and polar hydrophilic R groups on the outside
Which types of chemical interactions affect a proteins tertiary structure?
Hydrophobic interactions, ionic bonding, hydrogen bonding and disulphide bonding
quaternary structure
the formation of a protein of several polypeptide chains
Is denaturation irreversible?
No, sometimes it is reversible
How is denaturation reversible sometimes?
Denaturation does not affect the primary structure so if the denaturing agent is removed, the protein can refold
chaperones
protein helpers that help proteins fold properly
What are the three components of a nucleotide?
A nitrogenous base, a pentose sugar and one or more phosphate groups
Which carbon in the pentose sugar is a nitrogenous base attached to?
Carbon 1
Which carbon in the pentose sugar is a phosphate group attached to?
Carbon 5
In a polynucleotide, where does the incoming nucleotide attach?
The 5’ phosphate group of the incoming nucleotide attached to the 3’ hydroxyl group of the polynucleotide
What is the difference between deoxyribose and ribose?
Deoxyribose has a hydrogen at the 2’ position and ribose has a hydroxyl group at the 2’ position
Why are nitrogenous bases called ‘bases’?
They have an amino group attached and they are considered basic
Why are nitrogenous bases called ‘nitrogenous’?
Because they contain nitrogen
purine
nitrogenous base that has two carbon-nitrogen rings
Which nitrogenous bases are considered purines?
Adenine and guanine
pyrimidine
nitrogenous bases that have one carbon-nitrogen ring
Which nitrogenous bases are considered pyrimidines?
Cytosine, thymine and uracil
phosphodiester linkage
covalent bond where chains of nucleotides in a polynucleotide are held together by a phosphate group
How far is each nitrogenous base pair from the next pair?
0.34 nanometers
ribonucleotide
nucleotide made up of nitrogenous base, ribose sugar and phosphate group
What are the four major types of RNA?
Messenger RNA, transfer RNA, ribosomal RNA and microRNA
