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.
__________ are important in the pharmaceutical industry
Two enantiomers of a drug may have:
Usually, only :
Differing effects of enantiomers demonstrate that :
-Enantiomers
- different effects
-one isomer is biologically active
-organisms are sensitive to even subtle variations in molecules
ibuprofen
does…
effective enantiomer
ineffective enantiomer
-reduces inflammation and pain
S-ibuprofen
R-ibuprofen
albuterol
does…
effective enantiomer
ineffective enantiomer
relaxes bronchial muscles, improving airflow in asthma patients
R-albuterol
S-albuterol
The distinctive properties of an organic molecule depend on:
-the arrangement of its carbon skeleton
-the molecular components attached to that skeleton (functional groups or F(x).
Functional groups are:
the chemically reactive groups of atoms within an organic molecule - are involved in chemical reactions
Each functional group behaves……., and the number and arrangement of the groups help….
-consistently from one organic molecule to another
-give each molecule its unique properties
Six functional groups are important in the chemistry of life:
Hydroxyl (—OH),
Carbonyl (aldehydes, ketones) (> C=O)
Carboxyl(—COOH).
Amino (—NH2)
Sulfhydryl (-SH)
Phosphate (—OPO32–)
Hydroxyl group (—OH)
example…
info
compound name
-Ethanol, the alcohol present in alcoholic beverages
-Polar. Forms hydrogen bonds with water.
-Compound name: Alcohol
Carbonyl group ( C ═ O)
example
info
compound name
-Acetone, the simplest ketone and Propanal
-Sugars with ketone groups are called ketoses; those with aldehydes are called aldoses.
-Compound name: Ketone or aldehyde
Carboxyl group (—COOH)
example
info
compound name
-Acetic acid and Ionized form of —COOH
(carboxylate ion)
-Acts as an acid.
-Compound name: Carboxylic acid, or organic acid
Amino group (—NH2)
example
info
compound name
-Glycine and Ionized form of —NH2
-Acts as a base.
-Compound name: Amine
Sulfhydryl group (—SH)
example
info
compound name
-Cysteine
-Two —SH groups can react, forming a “cross-link” that helps stabilize protein structure.
-Compound name: Thiol
Phosphate group (—OPO32−)
example
info
compound name
-Glycerol phosphate
-Contributes negative charge. When attached, confers on a molecule the ability to react with water, releasing energy.
-Compound name: Organic phosphate
Methyl group (—CH3)
example
info
compound name
5-Methylcytosine
-Affects the expression of genes. Affects the shape and function of sex hormones.
-Compound name: Methylated compound
ATP
complete name
what it is
primary…
made up of:
react with:
adenosine triphosphate
-A modified adenosine nucleotide attached to a string of three phosphate groups
-It is the primary energy–transferring molecule in the cell to do work.
-A ribose sugar, a base, three phosphates
-ATP stores the potential to react with water
The versatility of carbon makes possible:
-the great diversity of organic molecules
-variation at the molecular level lies at the foundation of all biological diversity on our planet
The concept of vitalism:
Is the idea that…
Was disproved when…
-organic compounds arise only within living organisms
- chemists synthesized the compounds in the laboratory
STANLEY EXPERIMENT
experiment
result
conclusioon
-In 1953, Stanley Miller simulated environmental conditions on the lifeless, primordial Earth. Miller used electrical discharges to trigger reactions in a primitive “atmosphere” of H2O, H2, NH3 (ammonia), and CH4 (methane)—some of the gases released by volcanoes.
-A variety of organic compounds that play key roles in living cells were synthesized in Miller’s apparatus.
-Organic compounds may have been synthesized abiotically on the early Earth, setting the stage for the origin of life.
Some important functional groups of organic compounds:
-ALCOHOLS: (their specific names usually end in -ol)
-KETONES: if the carbonyl group is within a carbon skeleton
-ALDEHYDES: if the carbonyl group is at the end of the carbon skeleton
-CARBOXYLIC ACIDS, or organic acids
