Module 2: The Macromolecules of Life Flashcards
What are the 2 model systems for investigating chemical evolution?
Prebiotic soup model: proposes that certain molecules were synthesized from gases in the atmosphere or arrived via meteorites.
-They would condense with rain and accumulate in the ocean, resulting in an organic “soup”.
Surface metabolism model: suggests that dissolved gases came in contact with minerals lining the walls of deep-sea vents, forming increasingly complex organic molecules.
Alexander I Oparin
JBS Haldane
Stanley Miller
Alexander I Oparin: first proposed chemical evolution in 1924.
JBS Haldane: re-published Oparin’s proposal 5 years later.
Stanley Miller: American graduate student who tested the Oparin-Haldane hypothesis in 1953.
Photon
A discrete packet of light energy; a particle of light.
What are the 6 major functions of proteins?
- Defense
- Movement
- Catalysis
- Signalling
- Structure
- Transport
What 4 groups are present in all 20 amino acids?
- Hydrogen atom
- Amino group (NH2)
- Carboxyl group (COOH)
- R-group (side chain)
What are 3 questions you can ask to determine what type of amino acid an R-group is?
- Does it have a negative charge?
- If so, it is acidic and will lose a proton. - Does it have a positive charge?
- If so, it is basic and will gain a proton. - If it is uncharged, does it have an oxygen atom?
- If so, the electronegative oxygen will form a polar covalent bond in the R-group, making it uncharged polar.
Polymerization
The process of linking monomers together to form polymers.
Peptide bond
The covalent bond formed by a condensation reaction between 2 amino acids.
Oligopeptide
Polypeptide
Oligopeptide: a polymer consisting of 50 or fewer amino acids.
Polypeptide: polymers of 50 or more amino acids.
What are the 4 levels of protein structure?
- Primary - the sequences of amino acids in a polypeptide, stabilized by peptide bonds.
- Secondary - formation of alpha-helixes and beta-pleated sheets, stabilized by hydrogen bonding.
- Tertiary - overall 3-dimensional shape.
- Quaternary - shape produced by combinations of polypeptides.
Macromolecular machine
A group of proteins and possibly other macromolecules that assemble to carry out a particular function.
Substrate
A reactant that interacts with a catalyst, such as an enzyme, in a chemical reaction.
Active site
Location of the enzyme where substrates bind and react, causing catalysis.
Why are origin-of-life researchers skeptical that life began with a protein?
It would have needed to possess information, replicate and evolve. If they cannot replicate themselves, they cannot evolve on their own.
RNA world hypothesis
Proposal that at a particular stage in the evolution of life, RNA stored both genetic information and catalyzed its own replication.
Nucleoside
Nucleotide
Nucleoside: A molecule consisting of a 5-carbon sugar and one of several nitrogen-containing bases.
Nucleotide: Same as a nucleoside, plus one or more phosphate groups.
Phosphodiester bond
Chemical linkage between adjacent nucleotide residues in DNA and RNA.
Phosphodiester bonds between ribonucleotides produce the polymer RNA, bonds between deoxynucleotides produce DNA.
What are the 3 basic units that make up a nucleotide?
- A sugar
- At least one phosphate group
- A nitrogenous base
X-ray Crystallography
A technique for determining the 3D structure of macromolecules by analyzing the diffraction patterns produced by X-rays beamed at crystals of the molecule.
It found that DNA had a regular and repeating structure.
What are Chargoff’s 2 rules?
- The number of purines in a given DNA molecule is equal to the number of pyrimidines.
- The DNA molecule has an equal number of T’s and A’s, and an equal number of G’s and C’s.
Complimentary base pairing
The association between specific nitrogenous bases of nucleic acids stabilized in hydrogen bonding.
-Example: A+T/U, G+C.
Also known as Watson-Crick pairing.
What are the purines?
What are the pyrimidines?
Purines: Adenine, Guanine.
Pyrimidines: Cytosine, Urasil, Thymine.
Viroid
A pathogenic RNA molecule.
Ribozyme
Any RNA molecule that can act as a catalyst to increase the rate of a chemical reaction.
Carbohydrate polymers are made of __________ monomers.
Nucleic acid polymers are made of __________ monomers.
Protein polymers are made of __________ monomers.
Carbohydrate polymers are made of simple sugar monomers.
Nucleic acid polymers are made of nucleotide monomers.
Protein polymers are made of amino acid monomers.
Carbohydrate
Any class of molecules that contain:
- A carbonyl group (C=O)
- Several hydroxyl groups (-OH)
- Multiple carbon-hydrogen bonds (C-H)
Triose
Pentose
Hexose
Triose: a monosaccharide containing 3 carbon atoms.
Pentose: a monosaccharide containing 5 carbon atoms (ribose).
Hexose: a monosaccharide containing 6 carbon atoms (glucose).
Simple sugars differ from each other in what 3 ways?
- The location of their carbonyl group (C=O).
- The number of carbon atoms present.
- The spatial arrangement of their atoms (particularly the relative positions of their hydroxyl groups).
Glycosidic linkage
The covalent bond formed by a condensation reaction between two sugar monomers.
Also called glycosidic bond.