B1 Flashcards
Macromolecule
Very large molecule made up for many repeating sub-units
Monomers
Repeating small units that make up macromolecules
Smallest unit still classified as that molecule type
Condensation reaction
Reaction involving the formation of a covalent bond between two monomers to form polymers.
What is the role of water in a condensation reaction?
Remove hydroxyl (OH) from one monomer and hydrogen (H) from the other to make them reactive. Together, they combine to make H2O as a waste product.
Hydrolysis
Reaction that breaks bonds of the polymer to split into many monomers.
Role of water in hydrolysis
Water molecule is split. H is added to one monomer, and OH to the other. This stabilises monomers to prevent rebonding. Therefore, water is need (reactant)
What features of carbon make it able to form many unique compounds?
4 valence electrons in outer shell -> can form 4 covalent bonds (double or single). Very effective at forming bonds with other atoms
Can form long chains and rings
Monomer for carbohydrate
Monosaccharide
Monomer for lipids
Fatty acids (plus a glycerol and/or phosphate group)
Monomers for proteins
Amino acids
Monomers for nucleic acids
Nucleotides
Processes in body that use condensation reactions
Building body tissue
Protein synthesis
DNA replication and transcription
Glycogen and starch formation
Why is water produced when condensation reactions occur?
During these reactions, stable monomers must become reactive (by removing H from one monomer and OH from the other). H and OH combine to make water
What are examples of processes in your body that use hydrolysis reactions?
Anytime larger macromolecules are broken down to use the building blocks
e.g. digestion
What role does water play in hydrolysis reactions?
After breaking bonds in polymer, monomers are reactive. To prevent reconnection, H2O is split. H goes to one monomer, and OH to the other. This makes the monomers stable and non-reactive
Polymerisation of monosaccharides
OH is removed from C1 of one monosaccharide.
H is removed from C4 of one monosaccharide.
This generates a disaccharide, which will become a polysaccharide if the polymerisation continues. The bond is called a 1-4 glycosidic linkage. H2O is also produced
What is the name for the bond between monosaccharides?
1-4 glycosidic linkage
Polymerisation of fatty acids and glycerol
OH is removed from glycerol. H is removed from the fatty acid. This forms a bond between the C of the glycerol and the O of the fatty acid. The bond is called an ester linkage/bond. 3 H2O is also produced. Whole new molecule is a triglyceride
Name of the bond between fatty acids and glycerol
Ester linkage/bond
Name of molecule formed by polymerisation of fatty acids and glycerol
Triglyceride
Polymerisation of amino acids
OH off carboxyl end. H off amine group. Leads to a peptide bond between C of carboxyl group and N of amine group. H2O is also produced.
Molecule is called a dipeptide, and will become a polypeptide is continued
Name of bond between amino acids
Peptide bond
Polymerisation of nucleotide
H off C3 sugar
OH off phosphate group.
Leads to a phosphodiester bond, and water. Molecule is either DNA backbone (replication) for mRNA (transcription)
Name of bond between nucleotides
Phosphodiester bond
Monosaccharide
Monomer of all carbohydrates.
Traits of monosaccharides
5 or 6 carbons. Form rings in aqueous solutions
Examples of monosaccharides
Ribose, deoxyribose, glucose
Polysaccharide
When many monosaccharides are chemically bonded together (AKA complex carbohydrates). Can be broken into monosaccharides to provide energy or perform structure functions in cells
Cellulose
Polysaccharide that makes up cell walls in plants
Glycoproteins
Carbohydrate chemically bonded to a protein. Found in cell membrane where carbohydrate chain is anchored to a member protein
Pentose vs hexose sugar
Pentose monosaccharides: contains 5 carbons in carbon backbone C5H10O6
Hexose monosaccharide: contains 6 carbons in carbon backbone. C6H12O6
What makes glucose a polar molecule?
Its 5 hydroxyl groups, which exist in a polar covalent bond.
What type of molecule is glucose?
Monosaccharide
What is the charge distribution for a hydroxyl group?
H is slightly positive. O is slightly negative
Formula for glucose
C6H12O6
Alpha glucose v.s. beta glucose
At C1, alpha glucose has the H above the hexose ring and the OH below.
For beta glucose, the OH is above the hexose ring, and H is below it.
Structure of glucose
Six carbon. Hexose-ring
Order
O
C1 (H above, OH below for alpha. OH above, H below for beta)
C2 (H above, OH below)
C3 (Oh above, H below)
C4 (H above, OH below)
C5 (CH2OH branches off. C6 is this C)
Properties of glucose and how determined
Molecular stability (due to covalent bonds)
High solubility in water (due to polarity)
Easily transportable (due to solubility)
Yields high energy (ATP) when oxidised due to covalency
Examples of polysaccharides
Amylose
Amylopectin
Glycogen
Cellulose
Amylose strucutre
Straight chain of alpha glucose (i.e. long chain of glucose molecules). Only 1-4 linkages. Helix shape overall
Function of amylose
20% of plant starch; therefore, long-term storage in plants.
Storage function is facilitated by being able to be compact. Bonds between glucose molecules are easily broken by hydrolysis to free monosaccharides for cellular respiratoin
Amylopectin structure
Branched chain of alpha glucose. Made up of 1-4 linkages and some 1-6 linkages.
Function of amylopectin
80% of plant starch; therefore, long-term storage in plants.
Storage function is facilitated by being able to be compact. Bonds between glucose molecules are easily broken by hydrolysis to free monosaccharides for cellular respiratoin
Structure of glycogen
Highly branched chain of glucose. 1-4 linkages and lots of 1-6 linkages
Function of glycogen
Short-term energy storage for animals. Humans store in the liver
Why is glycogen ideal structurally for energy storage?
Can form coils/chains therefore compact storage molecules. Bonds between glucose molecuels can easily be broken by hydrolysis
Purpose of bonds between glucose in starch and glycogen being broken
To free monosaccharides for cellular respiration
Cellulose structure
Straight chain of alternating beta glucose (some flipped on x-axis). Only 1-4 linkages. Hydrogen bonds between long fibres
Function of cellulose
Structural component and strong fibes. Used for plant cell walls.
(Humans don’t break it down -> fibre)
What is a glycoprotein?
Carbohydrate chain attached to a cell membrane protein
Role of glycoproteins
Used for cell identification
Glycoproteins and ABO blood type
Glycogen proteins detect antigens for the blood types.
E.g.
Type A glycoproteins detect A antigens
Type B glycoproteins detect B antigen
Type AB glycoproteins detect A and B antigens
Type O glycoproteins detect neither
Phospholipids
Modified triglyceride that contains a glycerol, two fatty acids and a phosphate group (formed by a condensation reaction)
Adipose tissue
Composed of specialised cells (adipocytes) that store triglycerides as stored energy. Makes up body fat
Amphipathic
Molecule with body hydrophobic and hydrophilic regions
Endotherms
Organisms that maintain a steady internal temperature regardless of changes in external temperature
How do non-polar covalent bonds impact the characteristics of lipids?
Lipids are defined by long fatty acid chains that are made up of carbon and hydrogen (form non-polar covalent bonds). Therefore, lipids are non-polar and do not dissolve in water.
Types of lipid
triglycerides
phospholipid
steroids
Structure of triglyceride
Glycerol with three fatty acids. Can either be saturated or unsaturated
Function of triglycerides
Form adipose tissues. Stores triglycerides in cells
Why are triglycerides an effective molecule for long-term energy storage?
Stable but release lots of energy when broken
Hydrophobic (does not pull water)
Poor heat conductors (insulation)
Structure of phospholipid
Glycerol
2 x fatty acid
Phosphate
Can either be saturated or unsaturated
Function of phospholipid
Form bilayer of cells and organelle membranes
(amphipathic)
Structure of steroids
Form C-H rings instead of chains from cholestrol
Function of steroids
Make up steroid hormone messages.
Lipid-based = hydrophobic, can pass through all membrane to enter cells
Regions of phospholipid
Polar head
Non-polar fatty acid tails
How does the phosphate group become a part of the phospholipid?
Condensation reaction. OH removed from glycerol.
H removed from phosphate group. Form esther linkage
Types of fatty acids
Saturated
Monounsaturated
Polyunsaturated
Definition of saturated fatty acid
Only single bonds between carbons (straighter shape)
Properties of saturated fatty acids
Highly compressible -> efficient storage in adipose tissue
High MP due to stability -> solid fats
Examples of saturated fats
Form adipose tissue, fatty meats and butter
Monounsaturated fatty acid
One double bond ebtween carbons
Properties of monounsaturated fatty acids
Less dense, more spread out.
Ideal for cell membranes
Lower MP generally, so liquid at room temperature
Examples of monounsaturated fatty acids
Come from plants. Used for waterproof covering in plants
Olive oil
Polyunsaturated fatty acids
More than one double bond between Carbons
Properties of polyunsaturated fatty acids
Even lower melting point
Polyunsaturated fatty acids examples
Found in fatty fish, other plant oils, etc.
Has specific role in brain development
Peptide bond
Covalent bond between two amino acids
What is the peptide bond formed ebtween?
C of the carboxyl group and N of the amine group.P
Polypeptide
Chain of amino acids/polymers.
Denature
To lose the shape of a protein adn thus, losing function (by exposing to harsh environmental conditions)
HOw is a dipeptide made from two amino acids?
OH is removed from the carboxyl end of the first amino acid, and H is removed from the amine end of the 2nd amino acid. C from the carboxyl forms a peptide bond with the N of the amino acid. H2O is also produced
What does essential amino acid mean?
amino acids that one must eat in their exact form, as we don’t have the ability to synthesise them
Examples of important proteins in the body
Hemoglobin, collagen, keratin, histones, hormones
Structure of an amino acid
Amine group (NH2)
C
H
COOH (carboxyl group)
R group
Why does exposure to help temperatures cause denaturation for proteins?
Weaker folds between peptides hold the protein together, so the substrate is able to fit into the receptor.
Exposure to high temperatures break the weak folding bonds, so cannot find into the receptor.
R group
additional chain of elements coming from the central C in an amino acid. Makes each amino acid unique and gives them chemical properties
Hydrophobic interactions
When non-polar amino acids move inwards away from polar H2O molcules and thus, towards each other
Disulfide bond
Covalent bond between the sulfurs of the cysteine’s R group
Levels of protein structure
Primary
Secondary
Tertiary
Quaternary
How does the polarity of an amino acid impact their structure within the protein?
Determines tertiary structure of protein. Usually, polar amino acids surrounds the outside of the protein, while hydrophobic ones are in the centre
What do the chemical properties fo the R groups determine?>
The reactivity of the amino acid
Specific R group -> structure and shape of protein -> function of protein
Main categories of R groups
Non-polar: 9 (hydrophobic)
Polar: 6 (hydrophilic - form hydrogen bonds)
Charged: 5 (form ionic bonds)
Primary structure
specific sequence of amino acids joined together by strong covalent peptide bonds
What affects primary structure
Mutations (i.e. determined by DNA)
Does not denature
Secondary structure
Hydrogen bonds between C=O carboxyl of one amino acid and the N-H+ of another amino acid. Does not use R groups
Forms either one of two systematic patterns
Two systematic patterns of secondary structure
Beta-pleated sheet
ALpha helix
Alpha helix
Polypeptide is wound into a helix. H-bonds are between turns of helix
Beta-pleated sheet
Sections of the polypeptide run in opposite directiosn, and H bonds form between lines (giving a pleated shape because of bond angle)
What affects secondary structure?
Not mutation, as R groups are not used
H-bonds will break in extreme enviornments so will lose secondary structure in denaturation
Tertiary structure
Unique folding that results form specific R group interactions and bonds
Types of R group interactions (in order of most to least strength)
Disulfide bridges:
Ionic bonds
Hydrogen bonds
Hydrophobic interactions
Disulfide bridges
strong covalent bonds ebtween sulfur groups of cysteine amino acids
ionic bonds
hetween two oppositely charged amino aicds
hydrogen bond
forms between any polar amino acid
Hydrophobic interactions
tendency of non-polar amino acids to face away from water and towards each oterh
Most to least common R group interactions
Hydrophobic interactions
hydrogen bonds
ionic bonds
disulfide bridges
What affects tertiary structure
Extreme environments affect:
- temperature breaks H bonds
- pH change can break ionic bonds
Mutations change amino acids/R groups and alter tertiary structure. Some have more impact
i.e. polar -> polar = minimal
polar -> non-polar = major
Quaternary structure
Coming together of multiple polypeptides (and some non-popypeptide units) to form the protein
How are quaternary strucutre held together?
By R group interactions between amino acids of different chains. Same interactions as tertiary but between different polypeptides
Does all proteins have a quaternary structure?
No, not all
NOn-conjugated protein
Only contains polypeptide subunits
COnjugated protein
Contains at least one non-protein component
Example of conjugated protein
Heme groups
Globular proteins
Highly folded proteins that end up with a spherical shape.
Fibrous proteins
Long polypetides that lack tertiary bonds and folding /don’t have a consistent secondary structure.
how has cryogenic electron microscopy aided in our understanding of protein structure?
Enabled to see very small size. Involves flash freezing proteins in liquid ethane. Images can be obtained using beam of electrons. Software can then develop images and see individual atoms of a profile
What is an integral protein?
A protein that sits all the way through the whole phospholipid bilayer/membrane. must be amphipathic
Examples of important proteins
Collagen, insulin, haemoglobin
Structure of collagen
A fibrous protein (does not fold) made up of three polypeptide chains with repeating amino acid sequences held together by R group bonds.
Function of collagen
Strong (due to so many bonds) and elastic. used for structural body tissue: ligaments, tendons, cartilage , connective tissue
Structure of insulin
A non-conjugated globular protein made up of two polypeptide chains folded into a spherical shape and held together by disulphide bridges
Function of insulin
Hormone that binds to a receptor with a compatible shape. It decreases blood glucose by telling cells to take up carbohydrates
Haemoglobin strucyure
Globular conjugated protein made up for four polypeptide chains (two alphaglobin and two beta glob in) and four Heme groups
Function of haemoglobin
O2 attached to each of the Heme groups. Therefore each haemoglobin carries 4 O2, on the surface of red blood cells
What part of the protein structure does DNA affect?
Primary structure, due to deciding specific amino acid/R groups
What determines the tertiary and quaternary structure?
Folding by r groups
Outline impact of structure change on function
DNA -> specific amino acid (primary structure) -> folding by R groups (tertiary and quaternary structure) -> unique shape of protein -> determines what its compatibility -> function.
A change in the shape of the protein (mutation that affects primary structure OR extreme environments which impact tertiary)
