Chapter 1- The Molecules of Life Flashcards
What is an isotope?
Atoms of the same element that have different numbers of neutrons.
What are radioisotopes?
An unstable isotope that decays over time by emitting radiation.
What is a molecule?
A substance composed of two or more non-metal atoms that are covalently bonded together.
What is an organic molecule?
A carbon-containing molecule in which carbon atoms are nearly always bonded to each other and to hydrogen.
What is biochemistry?
The study of the activity and properties of biologically important molecules.
What does intramolecular mean?
Occurring between atoms within a molecule.
What does intermolecular mean?
Occurring between atoms of different molecules.
What is a hydrogen bond?
A weak association between an atom with partial negative charge and a hydrogen atom with partial positive charge.
What does hydrophobic mean?
Referring to non-polar molecules that do not have attractive interactions with water molecules.
What does hydrophilic mean?
Referring to polar molecules that have attractive interactions with water molecules.
What is an ion?
An atom or group of atoms that has gained or lost one or more electrons, giving it a positive or negative charge.
What is a functional group?
An atom or group of atoms attached to a molecule that gives the molecule particular chemical and physical properties.
What is a macromolecule?
A large, complex molecule, usually composed of repeating units of smaller molecules covalently linked together.
What is a polymer?
A large molecule composed of repeating units of smaller molecules (monomers).
What is a monomer?
The smallest repeating unit of a polymer.
What is a carbohydrate?
A biological macromolecule that contains carbon, hydrogen, and oxygen in a 1:2:1 ratio.
What is a monosaccharide?
A carbohydrate composed of between three and seven carbons.
What is an isomer?
One of two or more molecules with the same number and type of atoms, but different structural arrangements.
What is a disaccharide?
A carbohydrate composed of two monosaccharides joined by a covalent bond.
What is a polysaccharide?
A carbohydrate polymer composed of many monosaccharides joined by covalent bonds between particular atoms.
What is a lipid?
A biological macromolecule composed of carbon, hydrogen and oxygen atoms with a high proportion of non-polar carob-hydrogen bonds.
What is a triglyceride?
A lipid molecule composed of a glycerol molecule and three fatty acids linked by ester bonds.
What is a fatty acid?
A hydrocarbon chain ending in a carboxyl group.
What is a phospholipid?
A lipid composed of a glycerol molecule bonded to two fatty acids and a phosphate group with an R group.
What is a lipid bilayer?
A structure with hydrophilic “heads” of phospholipids directed toward the aqueous environment and hydrophobic “tails” directed toward the center, interacting with each other.
What is a steroid?
A lipid composed of four attached carbon-based rings.
What is wax?
Lipids composed of long carbon-based chains that are solids at room temperature.
What is protein?
A biological macromolecule composed of amino acid monomers linked by covalent bonds.
What is an amino acid?
An organic molecule composed of a central carbon atom bonded to a hydrogen atom, an amino group, a carboxyl group, and a variable R group.
What is a polypeptide?
A polymer composed of many amino acids linked together by a covalent bond.
What is a nucleic acid?
Biological macromolecules composed of nucleotide monomers.
What is DNA?
A biological macromolecule composed of nucleotides containing the sugar deoxyribose.
What is RNA?
A biological macromolecule composed of nucleotides containing the sugar ribose?
What is a nucleotide?
An organic molecule composed of a sugar bonded to a phosphate group and a nitrogen-containing base.
What is an acid?
A substance that produces hydrogen ions, H+, when dissolved in water.
What is a base?
A substance that produces hydroxide ions, OH-, when dissolved in water.
What is the pH scale?
A numerical scale ranging from 0 to 14 that is used to classify aqueous solutions as acidic, basic or neutral.
What is a neutralization reaction?
A chemical reaction between an acid and a base, producing water and a salt.
What is a buffer?
A substance that minimizes changes in pH by donating or accepting hydrogen ions as needed.
What is oxidation?
A process involving the loss of electrons.
What is reduction?
A process involving the gain of electrons.
What is a redox reaction?
A chemical reaction that involves the transfer of electrons from one substance to another; also called oxidation-reduction reaction.
What is a condensation reaction?
A chemical reaction that results in the formation of a covalent bond between two molecules with the production of a water molecule.
What is a hydrolysis reaction?
A chemical reaction that results in cleavage of a covalent bond with the addition of a water molecule.
What is activation energy?
The energy required to initiate a chemical reaction.
What is a catalyst?
A substance that speeds up the rate of a chemical reaction by lowering the activation energy for the reaction; is not consumed in the reaction.
What is an enzyme?
A biological macromolecule that catalyzes, or speeds up chemical reactions in biological systems.
What is an active site?
The site on an enzyme where the substrate binds; where the chemical reaction that is catalyzed by the enzyme takes place.
What is a substrate?
A reactant that interacts with the enzyme in an enzyme-catalyzed reaction.
What is the enzyme-substrate complex?
The combined structure of an enzyme with a substrate that is bound to the enzyme’s active site.
What is an inhibitor?
A molecule that binds to the allosteric or active site of an enzyme and causes a decrease in the activity of that enzyme.
What is an allosteric site?
A site on an enzyme that is not the active site, where other molecules can interact with and regulate the activity or the enzyme.
What is an activator?
A molecule that binds to the allosteric site of an enzyme and keeps an enzyme active or causes an increase in the activity of that enzyme.
What is the strongest force?
Intramolecular forces then intermolecular forces.
What is the structure of a monosaccharide? Give examples.
3 to 7 carbon atoms
Glucose, fructose, galactose
What is the structure of a disaccharide? Give examples.
Two monosaccharides joined by a glycosidic linkage.
Sucrose and lactose.
What is the structure of polysaccharides? Give examples.
Carbohydrate polymers of monosaccharides (usually glucose) joined covalently.
Glycogen- glucose stored by animals
Starch- glucose stored by plants
Cellulose- provides structural support in plant cell walls
What is the structure of a triglyceride?
Fatty acid is a hydrocarbon chain ending in a carboxyl group. It can either be saturated with no double bonds between carbon atoms OR unsaturated with one or more double bonds between carbon atoms,
What does the functional group hydroxyl have?
-OH
What does the functional group carbonyl have?
C=O
What does the functional group carboxyl have?
OH–C=O
What does the functional group amino have?
H-N-H
What does the functional group sulfhydryl have?
-S-H
What does the functional group phosphate have?
-O–P–O-
What is the monomer and polymer of carbohydrate?
Monomer- monosaccharide
Polymer- starch
What is the monomer and polymer of nucleic acid?
Monomer- Nucleotide
Polymer- DNA strand
What is the monomer and polymer of protein?
Monomer- amino acid
Polymer- Polypedtide
What is the monomer and polymer of lipids?
Monomer- fatty acid bonded to glycerol
Polymer- triglyceride
