Cellular Building Blocks
What are the 4 essential elemental components of biological structures?
C, H, O, N
How are large cellular structures formed? Give an example.
non-covalent associations of macromolecules that are thermodynamically favorable
e.g. hydrophobic interactions
(Why?)
What bonds comprise the cellular building blocks, and how are they formed?
1-2 types of monomer-monomer bonds formed by the endothermic elimination of H2O
(Why is this endothermic? What is the opposite process?)
What is the structure of the cell wall?
rigid, polymer glycan strands are crosslinked by peptide chains
Name and describe the 4 orders of protein structure
1) primary: sequence of amino acids
2) secondary: conformational patterns (e.g. type of helix)
3) complex folding caused by noncovalent and covalent R-group interactions
4) association of several polypeptides to form a functioning protein (e.g. hemoglobin)
(What is the difference between a polypeptide and a protein?)
What are the (4) building blocks of cells?
Carbohydrates/sugars; fatty acids; amino acids; nucleotides
What are the (2) purpose(s) of polysaccharides?
structural components (e.g. hexoses in the cell wall)
energy reserve (e.g. glycogen)
How are polysaccharides formed?
glycosidic bonds formed by the catalyzed elimination of water
(Discuss alpha vs. beta bond orientation)
What roles do glycosidic and peptide bonds have in the cell wall?
Glycosidic bonds confer strength on peptidoglycan around the circumference of the cell
Peptide bonds confer strength along the axis of the cell
Describe the 3 types of transport systems in a cell
1) Simple: driven by energy of proton motive force
2) ABC: binding proteins are involved; energy generated from ATP
3) Group translocation: chemical modification of the transported substance driven by phosphoenolpyruvate
Name 3 major covalent bond forming elements and 3 trace elements required for all organisms
Covalent: O, P, S, H, C, N
Trace elements: Mn, Fe, Co, Cu, Zn
Describe 3 functions of lipids and fatty acids:
1) semi-permeable barriers
2) highly concentrated, chemically reduced energy stores
3) signal molecules
(Based on structure, how are lipids used as a diffusion barrier?)
What are nucleic acids and how are they formed?
Nucleic acids are polymers of nucleotides connected by phosphate-sugar covalent bonds.
(Why are they important?)
What is the importance of the phospholipid bilayer and H-bonding in the cell membrane?
The hydrophobic part in the middle of the membrane is a diffusion barrier to polar molecules
H-bonding and hydrophobic interactions aid in membrane integrity without compromising fluidity
What are ribosomes and why are they important?
small structures that are 40% protein and 60% rRNA
sites of protein synthesis
Lipids are macromolecules containing ___; _____; and _____.
fatty acids; glycerol; and phosphate/sugars
How do fatty acids affect the properties of lipids?
The degree of unsaturation affects physical properties like melting point, flexibility, and degradability.
How are proteins formed?
dehydration of amino acids forms covalent peptide bonds
What is the function of the cell wall (3)?
What is chemotaxis?
chemoreceptors determine the concentration of a given chemical -> movement in response to the concentration gradient
(What is the organelle responsible for this "run and tumble" motion?)
What are the differences between DNA and RNA with respect to secondary structure?
DNA: double-stranded alpha helix with strands held together by H-bonding between complementary nitrogenous bases
RNA: single-stranded, folds over on itself in regions of complementary pairing
Amino acid monomers have ________; _______; and _____.
amine (basic) arm
carboxylic acid (acidic) arm
variable "R" group
(What does "R" represent?)
Bacteria & Eukarya: phospholipids are linked by ester bonds in the membrane bilayer
Archaea: branched fatty acids and ether links; can be monolayer membranes
List 5 functions of the cell membrane:
1) physical barrier composed of a bilayer of phospholipids
2) regulation of material movement
3) energy transduction (electron transfer chain, ATPases, etc.)
4) access to information via response proteins
5) intercellular interactions via attachment and gene transfer
Compare the functions of capsules and endospores.
Capsules: helps organisms flocculate and form biofilms; C storage/H2O storage; increases size
Endospores: dehydrated core with protected DNA that can remain dormant for many years, then become fully functional bacteria under appropriate conditions
(Both of these can have serious implications for water & wastewater treatment -- how?)