Biology 172 Lecture 3
Card Set Information
Biology 172 Lecture 3
Biology 172 Exam Review Lecture
Biology 172 Exam Review Lecture 3
Molecules with a preponderance of nonpolar covalent bonds cannot form _______ _____ from ________ ______ with water and is called __________
It takes a lot of energy to change the ________ of water
Substances that give up protons during chemical reactions to increase the proton concentration in water are called _____
Substances that lower the proton concentration during chemical reactions are called ________
Chemical properties of water that support life
Cohesion (hydrogen bonds)
Moderation of temperature (high specific heat)
Solvent for polar compounds
Most chemical reactions important for life take place in _________ _________
pH scale = -log[H+]
an acid increases [H+]
a base reduces [H+]
a buffer minimizes changes in [H+] and [OH-]
In cells, naturally occurring molecules act as ________ to maintain ___________
Functional groups _, _, _ dictate the types of reactions that organic molecules participate in
nucleotides (energy and signaling)
DNA = genetic info
RNA = intermediary between DNA and protein
In size and shape, proteins are the most diverse class of molecules know
Proteins Composed of Amino Acids
20 different types
each has a
differ in charge, polarity, and size, and 'R' group
At pH ___ (in a cell) the amino and carboxyl groups are ______
The side chain R groups are nonpolar.
Biological macromolecules (DNA, carbohydrates, proteins) are assembled into polymers by condensation reactions:
Condensation reactions: monomer in, water out (dehydration)
What is this type of reaction called?
what type of bond is formed?
R-groups in this polypeptide?
Dehydration (from condensation)
Covalent (polar) bond
Linear sequence of amino acids linked by ______ _____
Sequence is determined by _______ ________
Amino acids linked by ________ ______
why are polypeptide chains flexible?
9 amino acids
Because the groups on either side of each peptide bond can rotate about their single bonds
Why is this important?
Importance of primary structure
2. Protein Secondary Structure
Interactions between atoms in backbone held together by hydrogen bonds
Two main secondary structures
Stable 3D structures that form through hydrogen bonding of the backbone amino and carbonyl groups
Hydrogen bonds form between _____ _______ of one amino acid and ________ on amino group of another animo acid
Noncovalent bonds help _______ _____
attractive forces between oppositely charged molecules H bonding : attraction between electropositive hydrogen atom and 2 electron attracting atoms, usually O or N
Folded conformation in aqueous solution
Tertiary structure - overall 3-D shape of polypeptide. Held together by ....
interactions between atoms in R groups
-van der Waals
Shape of a complex of multiple polypeptide chains (subunits)
Held together by