biology EXAM #2 pt.1

Question 1

The Backbone of Biological Molecules

Answer 1

Carbon—

Question 2

All living organisms

Answer 2

Are made up of chemicals based mostly on the element carbon

Question 3

Stanley Miller’s classic experiment demonstrated

Answer 3

the abiotic synthesis of organic compounds

Question 4

what was the Stanley Miller’s classic experiment

Answer 4

an attempt at simulating ancient Earth conditions, more specifically, the ancient water cycle. It showed biomolecules can be formed under these conditions.

Question 5

Experiments support the idea that abiotic synthesis of organic compounds

Answer 5

, perhaps near volcanoes, could have been a stage in the origin of life

Question 6

Organic chemistry is the study of

Answer 6

carbon compounds, regardless of their origin

Question 7

Organic compounds:

Answer 7

Range from simple molecules to colossal ones:
Proteins, lipids, carbohydrates, nucleic acids

Question 8

Electron configuration determines

Answer 8

the kinds and number of bonds an atom will form with other atoms

Question 9

Carbon atoms can form diverse molecules by:

It has: (how many electrons)

This allows it to form :

Tetravalence:

Answer 9

• 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.

Question 10

The bonding versatility of carbon allows it to :

Answer 10

form many diverse molecules, including carbon skeletons (H, O, N, S, P and other C atoms )

Question 11

methane:

ethane:

ethene:

Answer 11

-CH4

-C2H6

-C2H4

Question 12

The number of unpaired electrons in the valence shell of an atom is generally equal to

Answer 12

its valence, the number of covalent bonds it can form

Question 13

The electron configuration of carbon gives it

Answer 13

covalent compatibility with many different elements

Question 14

number of valence
H
O
N
C

Answer 14

1
2
3
4

Question 15

Valence is the number of:

It is generally equal to the number of:

Answer 15

-covalent bonds an atom can form.

-electrons required to complete the atom’s outermost (valence) electron shell

Question 16

CO2 is the source of

Answer 16

carbon for all the organic molecules found in organisms.

Question 17

Simple molecules:
a)
b)

Answer 17

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.

Question 18

Carbon chains:
form
vary
a b c d

two examples

Answer 18

-the skeletons of most organic molecules

-Vary in length and shape

length
branching
double bonds
rings

-carbohydrates: starches and glycerol
sugars: ribose, glucose

Question 19

Hydrocarbons are:

two examples:

these molecules
-have:
-can:

Answer 19

-molecules consisting of only carbon and hydrogen

1. fossil fuels
2. fats have hydrocarbon components

-have non-polar carbon–to–hydrogen linkages
-can undergo reactions that release a relatively large amount of energy.

Question 20

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…

Answer 20

-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.

Question 21

Structural isomers have different:

______ isomers or ________ isomers have:

Enantiomers are isomers that:

Answer 21

• 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

Question 22

(a) Structural isomers:

(b) Geometric isomers:

(c) Enantiomers:

Answer 22

-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

Question 23

structural isomers :
The number of possible isomers increases…

There are only ________ but there are

Structural isomers may also differ in:

Answer 23

-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 .

Question 24

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

Answer 24

• 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.

Question 25

__________ are important in the pharmaceutical industry

Two enantiomers of a drug may have:

Usually, only :

Differing effects of enantiomers demonstrate that :

Answer 25

-Enantiomers

• different effects

-one isomer is biologically active

-organisms are sensitive to even subtle variations 
in molecules

Question 26

ibuprofen
does…
effective enantiomer
ineffective enantiomer

Answer 26

-reduces inflammation and pain
S-ibuprofen
R-ibuprofen

Question 27

albuterol
does…
effective enantiomer
ineffective enantiomer

Answer 27

relaxes bronchial muscles, improving airflow in asthma patients
R-albuterol
S-albuterol

Question 28

The distinctive properties of an organic molecule depend on:

Answer 28


-the arrangement of its carbon skeleton


-the molecular components attached to that skeleton (functional groups or F(x).

Question 29

Functional groups are:

Answer 29

the chemically reactive groups of atoms within an organic molecule - are involved in chemical reactions

Question 30

Each functional group behaves……., and the number and arrangement of the groups help….

Answer 30

-consistently from one organic molecule to another
-give each molecule its unique properties

Question 31

Six functional groups are important in the chemistry of life:

Answer 31

Hydroxyl (—OH),
Carbonyl (aldehydes, ketones) (> C=O)
Carboxyl(—COOH).
Amino (—NH2)
Sulfhydryl (-SH)
Phosphate (—OPO32–)

Question 32

Hydroxyl group (—OH)

example…
info

compound name

Answer 32

-Ethanol, the alcohol present in 
alcoholic beverages

-Polar. Forms hydrogen bonds with water.

-Compound name: Alcohol

Question 33

Carbonyl group ( C ═ O)

example
info

compound name

Answer 33

-Acetone, the simplest ketone and Propanal

-Sugars with ketone groups are called ketoses; those with aldehydes are called aldoses.

-Compound name: Ketone or aldehyde

Question 34

Carboxyl group (—COOH)

example
info

compound name

Answer 34

-Acetic acid and Ionized form of —COOH
(carboxylate ion)

-Acts as an acid.

-Compound name: Carboxylic acid, or organic acid

Question 35

Amino group (—NH2)

example
info
compound name

Answer 35

-Glycine and Ionized form of —NH2

-Acts as a base.

-Compound name: Amine

Question 36

Sulfhydryl group (—SH)

example
info
compound name

Answer 36

-Cysteine

-Two —SH groups can react, forming a “cross-link” that helps stabilize protein structure.

-Compound name: Thiol

Question 37

Phosphate group (—OPO32−)

example
info
compound name

Answer 37

-Glycerol phosphate

-Contributes negative charge. When attached, confers on a molecule the ability to react with water, releasing energy.

-Compound name: Organic phosphate

Question 38

Methyl group (—CH3)

example
info
compound name

Answer 38

5-Methylcytosine

-Affects the expression of genes. Affects the shape and function of sex hormones.

-Compound name: Methylated compound

Question 39

ATP
complete name
what it is
primary…
made up of:
react with:

Answer 39

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

Question 40

The versatility of carbon makes possible:

Answer 40

-the great diversity of organic molecules

-variation at the molecular level lies at the foundation of all biological diversity on our planet

Question 41

The concept of vitalism:
Is the idea that…
Was disproved when…

Answer 41

-organic compounds arise only within living organisms

• chemists synthesized the compounds in the laboratory

Question 42

STANLEY EXPERIMENT

experiment

result

conclusioon

Answer 42

-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.

Question 43

Some important functional groups of organic compounds:

Answer 43

-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