Module 2.2: Organic molecular structure of carbohydrates, amino acids and proteins Flashcards
what are the features of inorganic compounds?
- structurally simple
- usually lack carbon
- may have ionic or covalent bonds
- cant carry out complicated biological functions
- Examples: Water, Ammonia, Acids, Bases
what are the features of organic compounds?
- usually large and complex
- contain carbon bound to hydrogen
- covalent bonds
- carry out complex functions
- Examples: Proteins, Hormones, Carbohydrates, Lipids
what is the molecular formula for glucose?
C6H12O6
what is the function of an organic compound dependent on?
The function of an organic compound is dependent on the functional groups attached to it
what are the functional classes? draw them
aldehyde, ketone, alcohol, amino, carboxylic acid
describe aldehydes. example?
- Intermediates in metabolic pathways
- Contain carbonyl group (C=O) at end of carbon
chain, which makes them reactive - C=O located on last carbon of hydrocarbon chain
- Makes part of the molecule polar and hydrophilic
- Example: Formaldehyde (CH2O)
describe ketones. example?
- Intermediates in metabolic pathways
- Contain a carbonyl group within the hydrocarbon chain (not at the end)
- Less reactive than aldehydes because carbonyl group is flanked by two carbon atoms keeping it stable
- Makes part of molecule polar and hydrophilic
- Result from protein metabolism causing ketosis
- Example: Acetone (CH3COCH3)
describe alcohols. example?
- Involved in fermentation and metabolism
- Most alcohols are antibacterial
- Contain a hydroxyl group (-OH) attached to any carbon atom in molecule
- Makes molecule more polar and hydrophilic (dissolves easily in water)
- Can form hydrogen bonds due to –OH group
- Example: Ethanol (C2H6O) and Glucose
describe carboxylic acids. example?
- Found in fatty acids (lipids) and amino acids (proteins)
- Contain a carboxyl group (–COOH), combining carbonyl and hydroxyl groups
- Weak acids and highly reactivity, polar and
hydrophilic - All amino acids have a carboxyl group at one end
- Example: Acetic Acid (CH3COOH)
describe aminos. example?
- Found in amino acids (proteins), vitamins, and
neurotransmitters - Contain a nitrogen atom (-NH2)
- Nitrogen has a lone pair of electrons ready to accept hydrogen ions
- Can bind to hydrogen ions and act as a base
- Make molecule polar and hydrophilic
- Reactive and basic
- All amino acids have an amino group at one end
- other compounds with amino groups have names ending in “amide”
- Example: Methylamine (CH3NH2)
what is the building block for proteins
amino acids
why are proteins needed?
- Build muscle
- Make hormones
- Involved in cell communication (i.e. cell surface receptors, cytokines, and chemokines)
how many different amino acids do human proteins have?
Human proteins contain 21 different amino acids
how are amino acids obtained?
Nine essential amino acids must be obtained from diet because the human body cannot synthesize them
describe the features of a peptide
Size: Shorter (< 50 a.a.)
Structure: Simple, likely linear
Function: Signaling, basic biological roles
Complexity: Few levels of structure
Example: Oxytocin
describe the features of a protein
Size: Longer (> 50 a.a.)
structure: Complex, with specific 3D folding
function: Involved in structure, enzymes, transport; carrying out more complex functions
complexity: May have up to quaternary structure
example: hemoglobin
through which process are amino acids joined? how? what is the reversable reaction?
- Condensation Reaction (dehydration)
- Carboxy terminal group of one amino acid will
combine with the amide group of a second amino acid to produce a water molecule and a dipeptide - Reaction is reversible referred to a hydrolysis reaction
what is oxytocin?
Simple peptide made up of 9 amino acids
* Has unique disulphide bond within polypeptide chain affecting its structure
where is oxytocin produced?
Produced in hypothalamus and secreted by the
posterior pituitary gland
what does oxytocin do?
Promotes uterine contractions, maternal
bonding, and ejection of breast milk
what are the different protein types?
structural, regulatory, contractile, transport, catalyst, immunological
what is the function of structural proteins? example?
- Provide structural support to all parts of body
- Collagen: bone, other connective tissues
- Keratin: skin, hair, fingernails
what is the function of regulatory proteins? example?
Function as hormones to regulate physiological
processes; control growth and development;
neurotransmitters; mediate responses from nervous system
- Insulin: regulates blood sugar levels (made by pancreas)
- Substance P: mediates pain
sensation in nervous system
what is the function of contractile proteins? example?
Enable movement by contracting and relaxing
muscle fibers
Actin and Myosin: involved in muscle contraction
what is the function of immunological proteins? example?
Protect body from harmful pathogens and foreign substances
Antibodies, Cytokines, Chemokines
what is the function of transport proteins? example?
Carry substances across membranes or within the body
- Albumin: transports fatty acids, hormones
- Hemoglobin: transports oxygen in blood
what is the function of catalytic proteins? example?
Act as enzymes to induce chemical reactions (i.e.
enzymes)
- Amylase: breaks down starch into sugars
- DNA polymerase: Assists in DNA replication
what are the chemical properties of side chains?
charge, Hydrophobicity, Polarity and Hydrophilicity
describe charge in side chains
Allows attraction and ionic bonding between proteins and other compounds
describe Hydrophobicity in side chains
- Allow interaction with other lipids
- Hydrophobic hydrocarbon chains or rings can collapse in the middle of globular proteins affecting their shape
describe Polarity and Hydrophilicity in side chains
Allows greater solubility in watery fluids
describe the first step in protein organizational structure and what its called
Primary structure is the sequence of amino acids
* It is unique to that protein
* Defines the structure and function of protein
* Usually shown using 3 letter abbreviations for each type of amino acid
describe the second step in protein organizational structure and what its called
Secondary structures occur when
polypeptides are joined by intrachain H-
bonds (not disulphide bonds)
* Coiled strings like an alpha helices
* Flattened sheet like a beta-pleated sheets
describe the third step in protein organizational structure and what its called
tertiary structure
Formed by folding secondary structures like alpha helices and beta sheets into a specific
complex, functional 3D structure
describe the fourth step in protein organizational structure and what its called
quaternary
* Two or more folded tertiary proteins bound
together to form a larger protein
* Generally, enzymes and transport proteins are
made of two or more parts
* Normal adult hemoglobin has 2 alpha and 2 beta protein chains
what can gene mutation alter?
A gene mutation alters the amino acid sequence of the protein produced from that gene
describe how gene mutation can be problematic or not problematic
- Mutation changes amino acid sequence → protein function altered
- Mutation changes amino acid sequence → protein function unaltered
Amino acid sequences are BLANK in BLANK
encoded, genes
describe sickle cell anemia
Genetic blood disorder caused by an inherited
mutation that encodes hemoglobin
* Affects beta-globin chain of hemoglobin
* Affects shape and function of red blood cells (RBCs)
* RBCs are rigid, crescent sickle shape
* Leads to health complications – pain, tissue
damage
* One amino acid switch promotes disease
* Glutamic acid (polar a.a.) replaced with valine (hydrophobic a.a.)
what is hemoglobins purpose
transports oxygen throughout body
describe the consequences of an amino switch in sickle cell anemia
- Hemoglobin is less water soluble, does not fold well leading to the sickle shape
- RBCs are less pliable, cannot pass through tiny capillaries promoting blockages
- Premature RBCs are sent to spleen for destruction (hemolytic anemia)
what does a proteins function depend on?
A protein’s function depends on its tertiary (3D) structure
what happens if the tertiary structure of a protein is disrupted. how does this happen?
the protein becomes denatures and loses it activity or function
* Sensitive to pH, temperature, chemicals
what is tertiary structure in proteins maintained by?
- Disulphide bonds
- Hydrogen + ionic bonds (hydrophilic)
- Hydrophobic interactions (nonpolar side chains)
