Unit 2 - Molecules Flashcards
Hydrogen bonds
Weak bonds that form between the slightly neg. end and the slightly pos. end of two molecules. PLAYS A BIG ROLE IN BIOLOGY
When do polar covalent bonds occur?
When one nucleus has a slightly positive charge (larger nucleus attracts electrons more strongly so it develops a slightly neg. charge while the smaller nucleus has a slightly pos. charge)
Tell me about water
It’s a polar covalent molecule, it forms hydrogen bonds with itself (cohesion), it’s essential for life, and ice floats (it’s less dense than water)
What 6 biologically important functions does water perform?
- Regulates body temperature (has a high heat capacity) 2. Universal solvent (dissolves ionic + polar substances) 3. Transport medium (solutes, heat, etc) 4. Lubricant (joints) 5. Ampiphrotic (acts as both acid/base) 6. Cohesion/ Adhesion
Acid
Any substance which releases H+ when it dissociates (pH 0-7)
Base
Any substance which releases OH+ when it dissociates (pH 7-14)
Substances which resist small changes in pH
Buffers
Most biological systems require a pH scale near _____
Neutral (Ex. Blood : pH 7.4, a pH of 7.8 is fatal)
Oxidation
The loss of electrons or hydrogen atoms in a reaction (An element that loses electrons or H+ in a chemical reaction has been “oxidized”)
Reduction
The gain of electrons or H+ atoms in a reaction (The reactant which had gained atoms or H+ atoms has been “reduced”)
Another way to say natural selection
Differential survival
Polar covalent bonds must be _____ (structure/shape)
Asymmetrical
What 4 elements make up 99% of the mass of most cells?
C,H,O,N
The 4 levels of biomolecules
LEVEL 4: cell + organelles LEVEL 3: supramolecular complexes (chromosome, cell wall, plasma membrane) LEVEL 2: macromolecules (DNA, protein, cellulose) LEVEL 1: mononumeric units (nucleotides, amino acids, sugars)
3 cellular uses of biological molecules
Anabolism, catabolism, enzymes
Anabolism
When molecules are joined together to form a larger molecule, results in loss of water (BY DEHYDRATION SYNTHESIS)
Catabolism
when a molecule is broken down into two or more smaller molecules, results in addition of water (BY HYDROLYSIS)
Enzymes
A special class of proteins that speed up and initiate all chemical reactions in cells
Draw dehydration synthesis
Draw hydrolysis
What is an organic compound
A compound (that makes up living things) that consists of carbon and hydrogen atoms covalent my bonded to each other + other elements (CAN BE CALLED HYDROCARBONS) (Can form polymers by joining monomers)
What are the four groups of organic compounds
- carbohydrates - lipids - proteins - nucleic acids
What can Carbon do that makes it so essential (in organic compounds)
- form covalent bonds to as many as four other atoms - rotate freely around a single covalent bond - form a variety of structures
What’s a functional group
Atoms or groups of atoms that are attached to carbon backbones (provide distinct properties, such as solubility and chemical reactivity)
Name and draw the four functional groups we have to know
- HYDROXYL (-OH) 2. CARBOXYL (-COOH) 3. AMINE (-NH2) 4. PHOSPHATE (-H2PO4)
