Midterm 1

Question 1

what are unique features of life?

Answer 1

-highly organized
-highly complex
-transforms energy to maintain high order
–>phototrophs:energy from light
–>chemotrophs: energy from chemical fuel (break bonds to power formation of other bonds)
-self replicating with high fidelity
-myriad of chemical reactions organized in cells

Question 2

cell size

Answer 2

lower limit: accommodate sufficient molecules
upper limit: diffusion of molecules
range from 300 nm (mycoplasma) to 20 cm (ostrich egg)

Question 3

endomembrane system

Answer 3

-ER
-golgi apparatus
-lysosomes
-endosomes
-vacuoles

Question 4

endoplasmic reticulum (ER)

Answer 4

-site of protein synthesis
-usually contains ribosomes (rough ER)

Question 5

golgi apparatus

Answer 5

-separate and modify proteins
-vesicles contain protein–> goal of golgi is to separate protein

Question 6

origins of mitochondria and chloroplasts

Answer 6

endosymbionts
-ancestral prokaryote engulfed another prokaryote, resulting in mitochondria and chloroplasts located in a eukaryote

Question 7

what are 4 non-covalent interactions that are important for biomolecular assembly?

Answer 7

1. electrostatic interactions
   2.Van derWaals interactions (dispersion)
2. hydrogen bonds
3. hydrophobic effect

Question 8

electrostatic interactions

Answer 8

charge-charge (positive, negative)
charge-dipole
dipole-dipole

Question 9

van der waals interactions

Answer 9

-tight packing of atoms in biomolecules
-weak
-close range only
-attractive or repulsive

Question 10

hydrogen bonds

Answer 10

-biomolecules often have an electronegative atom (donor) that shares an H atom
-H bond lined up with covalent bond is stronger
-easier to break than covalent bonds

Question 11

structure of water

Answer 11

-ordered, cohesive
-high melting point, heat of vaporization
-liquid:H bonds “flicker” (amount of Hbonds can vary
-ice: stable, always has 4 H bonds

Question 12

hydrophobic effect

Answer 12

phospholipids
-polar head, interact with water thru hydrostatic interactions
-nonpolar tail, interact with other tails thru vander waals interactions
-are amphipathic
-maximizes water entropy
-drives protein folding

Question 13

qualities of water

Answer 13

1. water is a solvent
2. water as a reactant (hydrolysis and condensation)
   3.water as a heat buffer

Question 14

water as a solvent

Answer 14

-polarity of water breaks electrostatic interactions
-allows high concentrations of solutes

Question 15

water as a reactant

Answer 15

-hydrolysis (water breakage)
-condensation (produces water)
OR
-hydration (adding water)
-dehydration (removing water)

Question 16

water as a heat buffer

Answer 16

-high specific heat of water
–>cooling is counteracted by heat release
–>warming is counteracted by heat uptake
-perspiration requires heat input to vaporize
-water moderates environmental temperature