1.1/1.2 Flashcards
Isotope
Atoms of the same element that have different numbers of neutrons
Radioisotope
An unstable isotope that decays over time by emitting radiation
Molecule
A substance composed of two or more non-metal atoms that are covalently bonded together
Organic Molecule
A carbon-containing molecule in which carbon atoms are nearly always bonded to each other and to hydrogen
Biochemistry
The study of the activity and the properties of biologically important molecules
Intramolecular
Occurring between atoms within a molecule
Intermolecular
Occurring between atoms of different molecules
Hydrogen Bond
A weak association between an atom with partial negative charge and a hydrogen atom with partial positive charge
Hydrophobic
Water-fearing, referring to non-polar molecules that do not have attractive interaction with water molecules
Hydrophilic
Water-loving, referring to polar molecules that have attractive interactions with water molecules
Ion
An atom or group of atoms that has gained or lost one or more electrons, giving it a positive or negative charge
Functional Group
An atom or group of atoms attached to a molecule that gives the molecule particular chemical and physical properties
6 Elements of Life
Carbon, Oxygen, Hydrogen, Sulfur, Nitrogen, Phophorus
Which elements have a high electronegativity?
Oxygen, Nitrogen, Chlorine
Which elements have a low electronegativity?
Hydrogen, Carbon, Phosphorus
Polar Covalent Bond
An unequal sharing of electrons between elements that results in partial charges being formed
What happens when oil and water are mixed?
The oil will clump together because it is non-polar and cannot interact with the polar water molecules. It is hydrophobic.
Which molecules tend to be hydrophobic?
Non-polar molecules
Which molecules tend to be hydrophilic?
Polar Molecules
What is the hydrophobic effect?
The natural clumping together of non-polar molecules in water.
What is the importance of H+ ions?
Critical for many biological processes including cellular respiration.
What is the importance of Na+ ions?
They are part of transport mechanisms that enable specific molecules to enter cells.
What is special about the covalent bonds between H and C?
They are ‘energy-rich’ and therefore release a large amount of energy when bonds are broken.
What atoms do functional groups tend to contain?
Oxygen, Sulfur, Nitrogen, Phosphorus
What does the functional group give to the molecule that it is bonded to?
The same chemical properties that the functional group has.
Hydroxyl
Structural Formula: OH-
Properties: Polar
Found In: Carbohydrates, Lipids, Proteins, Nucleic Acids
Carbonyl
Structural Formula: C=O
Properties: Polar
Found In: Carbohydrates, Nucleic Acids
when the carbonyl is on a terminal carbon it is called aldehyde and when it is on any carbon not at the end of a chain it is called a ketone
Carboxyl
Structural Formula: OH-C=O
Properties: Polar, Acidic (proton donator)
Found In: Lipids, Proteins
Amino
Structural Formula: NH2
Properties: Polar, Basic (proton acceptor)
Found In: Proteins, Nucleic Acids
Sulfhydryl
Structural Formula: S-H
Properties: Slightly Polar
Found In: Proteins
as part of a side chain in an amino acid, sulfhydryls are critical in forming disulphide bridges that help proteins hold their proper shape
Phosphate
Structural Formula: PO4
Properties: Polar, Negatively Charged
Found In: Nucleic Acids
Molecular Formula
Shows the number of each type of atom in an element or compound
Structural Formula
Shows how the different atoms of a molecule are bonded together using single and double bonds
Macromolecules
A large, complex molecule, usually composed of repeating units of smaller molecules covalently linked together
Polymers
A large molecule composed of repeating units of smaller molecules (monomers) that are linked together by covalent bonds
Monomer
The smallest repeating unit of a polymer
Four Main Biological Macromolecules
Carbohydrates, Lipids, Proteins, Nucleic Acids
Carbohydrate
A biological macromolecules that contains carbon, hydrogen, and oxygen in a 1:2:1 ratio
Monosaccharide
A carbohydrate that has between 3 and 7 carbon atoms
Examples of Monosaccharides
Glucose (blood sugar), Fructose (fruit sugar), Galactose (sugar in milk)
Isomer
One of two or more molecules with the same number and type of atoms, but different structural arrangements
Examples of Isomers
Glucose, Fructose, Galactose
Disaccharide
A carbohydrate composed of two monosaccharides joined by a covalent bond
Glycosidic Linkage
The covalent bond between monosaccharides which forms between specific hydroxyl groups on each monosaccharide
Examples of Disaccharides
Sucrose (Glucose + Fructose), Lactose (Galactose + Glucose), Maltose (Glucose + Glucose)
Polysaccharide
A carbohydrate polymer composed of many monosaccharides joined by covalent bonds between particular atoms
Examples of Polysaccharides
Starch (Amylose), Glycogen, Cellulose
Difference between Amylose (starch) and Cellulose
In amylose all the units are oriented in the same direction but with cellulose they alternate direction
What two positions exist for the hydroxyl group on carbon-1 of glucose?
Alpha: H on top and OH on bottom (HOH), results in starch
Beta: OH on top and H on bottom (OHH), results in cellulose
Lipid
A biological macromolecule composed of carbon, hydrogen, and oxygen atoms, with a high proportion of non-polar carbon-hydrogen bonds
Why do lipids provide more energy than carbohydrates?
Greater proportion of carbon-hydrogen bonds compared to oxygen than in carbohydrates.
Why are lipids hydrophobic?
Large amount of non-polar hydrogen and carbon bonds
How are lipids crucial to life?
1) Insulate against heat loss.
2) Form Protective Cushion Around Major Organs
3) Major Component of Cell Membranes
Triglyceride
A lipid molecule composed of a glycerol molecule and three fatty acids linked by ester bonds
Ester Linkage
Bond between the hydroxyl group on a glycerol molecule and the carboxyl group on a fatty acid
Fatty Acid
A hydrocarbon chain ending in a carboxyl group
Saturated Fatty Acids
- no double bonds between carbon atoms
- animal fats
- solid at room temperature
Unsaturated Fatty Acids
- has one or more double bonds between carbons meaning there is less hydrogen and molecule has a kink
- plant fat
- liquid at room temperature
- one double bond (monounsaturated), two or more double bonds (polyunsaturated)
Cis and Trans At Double Bonds in Triglycerides
Cis: Hydrogens are on the same side at a double bond
Trans: hydrogens are on opposite sides
Phospholipid
A lipid composed of a glycerol molecule bonded to two fatty acids and a phosphate group with an R group.
Main components of cell membranes.
Describe the interaction between the head and tail of a phospholipid.
- the head contains the polar phosphate group so it is hydrophilic
- the tail contains the non-polar hydrocarbons of the fatty acids and it is hydrophobic
- therefore the hydrophobic tails are directed to the inside where they interact with other tails and the hydrophilic heads face outward toward the aqueous environment
Lipid Bilayer
A structure with hydrophilic “heads” of phospholipids directed toward the aqueous environment and hydrophobic “tails” directed toward the centre, interacting with each other.
Steroid
A lipid composed of four attached carbon-based rings.
Wax
Lipids composed of long carbon-based chains that are solids at room temperature.
Protein
A biological macromolecule composed of amino acid monomers linked by covalent bonds.
Different Functions of Proteins (6)
1) Catalyzing Chemical Reactions: Enzymes
2) Providing Structural Support; Collagen, Keratin
3) Transporting Substances in Body: Hemoglobin
4) Enabling Organisms to Move: Actin and Myosin
5) Regulating Cellular Processes: Hormones
6) Providing Defence From Disease: Antibodies
Amino Acid
An organic molecule composed of a central carbon atom bonded to a hydrogen atom, an amino group (NH2), a carboxyl group (COOH) and a variable R group
Where do the properties of an amino acid result from considering their underlying structure is the same?
The R group (Radical Group) or Side Chain that is different for all 20 amino acids.
Peptide Bonds
Covalent Bonds Between Amino Acids That Form Between the Carboxyl Group on One and the Amino Group on Another
Polypeptide
A polymer composed of many amino acids linked together by covalent bonds
Four levels of structure/organization for proteins
1) Primary Structure
2) Secondary Structure
3) Tertiary
4) Quaternary
Primary Structure Of Proteins
Linear sequence of amino acids with polar peptide bonds making hydrogen bonding possible
Secondary Structure of a Protein
Hydrogen bonding where a polypeptide can form a coil like shape…
1) Alpha Helix: Folded fan-like shape, pig’s tail
2) Beta Pleated Sheet: Accordion shape
Tertiary Structure of Proteins
- Folding of secondary structure as the peptide bonds and the different R groups in a polypeptide chain interact with each other and the aqueous environment of the cell .
- Hydrophobic effect: Polar hydrophilic groups will be directed toward the aqueous environment, while non-polar hydrophobic groups will tend to be directed toward the interior
Quaternary Structure of Proteins
Joining of Separate Chains
Denaturation
The unfolding of proteins
Nucleic Acid
Biological macromolecules composed of nucleotide monomers
DNA (deoxyribonucleic acid)
A biological macromolecule composed of nucleotides containing the sugar deoxyribose
RNA (ribonucleic acid)
A biological macromolecule composed of nucleotides containing the sugar ribose
Nucleotide
An organic molecule composed of a sugar bonded to a phosphate group and a nitrogen-containing base
Makeup of DNA
- deoxyribose sugar (5 carbons)
- phosphate group
- nitrogenous base: guanine, adenine, thymine, cytosine
- two strands twisted to form double helix
Makeup of RNA
- ribose sugar (5 carbons)
- phosphate group
- nitrogenous bases: guanine, adenine, cytosine, uracil
- single-stranded
Phosphodiester Bond
Covalent bond between adjacent nucleotide occurring between phosphate group on one nucleotide and the hydroxyl group on the sugar of the next nucleotide
Structural Isomer
Isomers with the same molecular formula but different structural formula
Stereoisomers
Isomers with the same arrangement of atoms but with a different orientation in space
Functions of Carbohydrates
- provide energy
- cellulose provides structural support in plants
Function of Nucleic Acids
DNA: stores genetic info of an organism
RNA: participates in protein synthesis
What solution is used to test for carbohydrates?
Benedict’s Reagent (Blue, Light Green, Green to Yellow, Orange, Red to Red-Brown)
What solution is used to test for starch?
Lugol’s Solution (iodine will turn blue-black)
What is used to test for lipids?
Translucent Lipid Test (Paper bag that becomes translucent when dry)
What solution is used to test for proteins?
Biuret Reagent (Blue, Pink (+), Violet (++), Purple(+++))
