biology EXAM #2 pt.1 Flashcards
The Backbone of Biological Molecules
Carbon—
All living organisms
Are made up of chemicals based mostly on the element carbon
Stanley Miller’s classic experiment demonstrated
the abiotic synthesis of organic compounds
what was the Stanley Miller’s classic experiment
an attempt at simulating ancient Earth conditions, more specifically, the ancient water cycle. It showed biomolecules can be formed under these conditions.
Experiments support the idea that abiotic synthesis of organic compounds
, perhaps near volcanoes, could have been a stage in the origin of life
Organic chemistry is the study of
carbon compounds, regardless of their origin
Organic compounds:
Range from simple molecules to colossal ones:
Proteins, lipids, carbohydrates, nucleic acids
Electron configuration determines
the kinds and number of bonds an atom will form with other atoms
Carbon atoms can form diverse molecules by:
It has: (how many electrons)
This allows it to form :
Tetravalence:
- bonding to four other atoms
-six electrons, four on in outer shell: therefore, carbon has four valence electrons
-four covalent bonds with a variety of atoms (preferred bonding)
- Each carbon atom acts as an intersection point from which a molecule can branch off in up to four directions.
The bonding versatility of carbon allows it to :
form many diverse molecules, including carbon skeletons (H, O, N, S, P and other C atoms )
methane:
ethane:
ethene:
-CH4
-C2H6
-C2H4
The number of unpaired electrons in the valence shell of an atom is generally equal to
its valence, the number of covalent bonds it can form
The electron configuration of carbon gives it
covalent compatibility with many different elements
number of valence
H
O
N
C
1
2
3
4
Valence is the number of:
It is generally equal to the number of:
-covalent bonds an atom can form.
-electrons required to complete the atom’s outermost (valence) electron shell
CO2 is the source of
carbon for all the organic molecules found in organisms.
Simple molecules:
a)
b)
a) carbon dioxide O = C = O
b) urea CO(NH2)2. organic compound found in urine. Frederich Wohler learned to synthesized In early 19th century.
Carbon chains:
form
vary
a b c d
two examples
-the skeletons of most organic molecules
-Vary in length and shape
length
branching
double bonds
rings
-carbohydrates: starches and glycerol
sugars: ribose, glucose
Hydrocarbons are:
two examples:
these molecules
-have:
-can:
-molecules consisting of only carbon and hydrogen
- fossil fuels
- fats have hydrocarbon components
-have non-polar carbon–to–hydrogen linkages
-can undergo reactions that release a relatively large amount of energy.
Isomers are :
_______ for AD/HD. (…)
Antidepressant ________ and ________ selective serotonin reuptake inhibitor (SSRI).
which type of isomer is active and which isn’t?
THALIDOMIDE, a drug prescribed for…
The drug was a mixture of…
-molecules with the same molecular formula but different structures and properties
-Focalin (d-isomer is the active form… l-isomer has little or no activity)
-citalopram and Lexapro(primarily S isomer)
- S isomer is active, the r isomer is not.
-celexa has a higher percent of the R isomer (no activity)
-a drug prescribed for thousands of pregnant women in the late 1950s and early 1960s.
-Mixture of two enantiomers, one reduced morning sickness, the desired effect, but the other caused severe birth defects.
Structural isomers have different:
______ isomers or ________ isomers have:
Enantiomers are isomers that:
- covalent arrangements of their atoms
-Cis-trans isomers or Geometric isomers have the same covalent bonds but differ in their spatial arrangements
- mirror images of each other
(a) Structural isomers:
(b) Geometric isomers:
(c) Enantiomers:
-differ in covalent partner or arrangement of C skeleton
-differ in their spacial arrangement , same covalent partner
-differ in spacial arrangement around an asymetric carbon resulting in mirror images molecules
structural isomers :
The number of possible isomers increases…
There are only ________ but there are
Structural isomers may also differ in:
-as carbon skeletons increase in size.
-three pentanes; 18 variations of C8H18 and 366,319 possible structural isomers of C20H42.
-the location of double bonds .
geometric isomers have:
Geometric isomers arise from the :
Each of the carbons has an ____________ attached to it, but one isomer…., and the other isomer has…
The subtle difference in shape between geometric isomers can dramatically affect
- the same covalent partnerships, but they differ in their spatial arrangements.
-inflexibility of double bonds.
-H and an X; but one isomer has a “cis ” arrangement, with two Xs on the same side relative to the double bond. and the other isomer has a “ trans ” arrangement, with the Xs on opposite sides.
-the biological activities of organic molecules.
