bio ch 4 mastering biology

which of these is an amino group?

a. NH2

These molecules are _____.

enantiomers

These molecules are _____.

structural isomers (The two molecules differ in the covalent bond relationships among their atoms.)

Functional groups confer specific chemical properties to the molecules of which they are a part. In this activity, you will identify which compounds exhibit certain chemical properties as well as examples of those six different compounds. Drag one molecule and one chemical property to each bin. If one property can apply to more than one functional group, choose the best answer for each functional group

-alcohol: is highly polar and may act as a weak acid (OH) -carboxylic acid: acts as an acid (COOH)aldehyde: may be a structural isomer of a ketone (C=O) -thiol: forms disulfide bonds (S-H) -amine: acts as a base (NH2) -organic phosphate: contributes negative charge (PO4)

Which of the functional groups behaves as a base?

A (amino group) (the electronegativity of nitrogen means that amino groups tend to pick up hydrogen ions)

Which chemical group is most likely to be responsible for an organic molecule behaving as a base?

Amino

Identify the functional groups.

Amino and carboxyl are functional groups. (Read about the variety of biologically important functional groups and note the structure and functional properties of amino and carboxyl groups.)

Which of these is a phosphate group?

B Of the choices, this is the only one that contains phosphorus.

Which of these is a carbonyl group?

C This is a carbonyl group.

Which of the following is a hydrocarbon? 1.C3H8 2.CCl2F2 3.CO2 4.H2CO3 5.C6H12O6

C3H8 (This is a typical hydrocarbon with single covalent bonds; the number of hydrogen atoms is equal to two times the number of carbon atoms plus 2.)

The large diversity of shapes of biological molecules is possible because of the extensive presence of _____ in the molecules.

Carbon (With four electrons to share, carbon-based molecules can be multibranching and three-dimensionally variable.)

Which of these is a hydroxyl group?

D This is a hydroxyl group.

Which statement about isomers is correct?

Enantiomers differ in biological activity. (Because enantiomers are mirror images of each other, working molecules distinguish the two versions by shape. Usually, one isomer is biologically active and the other is inactive.)

Which of these is a carboxyl group?

F This is a carboxyl group

Which of functional groups listed below behaves as an acid?

F By donating hydrogen ions, carboxyl groups act as an acid.

The molecule shown here contains four functional groups. Highlight all the atoms of the four functional groups, but do not highlight any bonds. When you click on each atom, it will change color. To deselect an atom, click on it again. Before you submit, check that you have not selected any bonds.

H-S PO4 O-H NH2 A functional group is a group of atoms bonded together in a specific way that can replace a hydrogen atom in a hydrocarbon. The molecule shown here contains four functional groups (−OH−OH, −SH−SH, −NH2−NH2, and −OPO2−3−OPO32−) attached to a carbon chain that is six carbon atoms long.

Most organic compounds contain carbon and _____.

Hydrogen (In fact, some argue that carbon dioxide should not be considered an organic molecule because it does not contain hydrogen.)

How do isomers differ from one another?

Isomers differ in the arrangement or bonding of atoms. (Isomers may differ in the covalent arrangements of their atoms or the position of double bonds within the molecule and thus have different chemical properties.)

What kind of effect does R-dopa have on Parkinson's disease?

None

L-dopa is used to treat _____

Parkinson's disease (People with Parkinson's disease lack dopamine.)

Which molecules show an appropriate number of bonds around each carbon atom?

Since carbon atoms are tetravalent (able to form four bonds), atoms may branch off a carbon atom in as many as four places. The ability of a carbon atom to form four different bonds allows carbon to form many different sizes and types of molecules. Carbon atoms may form chains, rings, or combinations of chains and rings. The tetravalence of carbon makes it particularly well-suited to forming the backbone of a huge diversity of organic molecules.

Which of the following best describes cis-trans isomers? See Concept 4.2

They differ in their spatial arrangement around inflexible double bonds (Cis-trans isomers maintain the same covalent partnerships, but the atoms may be arranged differently.)

Enantiomers are molecules that _____.

are mirror images

Which of these groups plays a major role in energy transfer?

b. Phosphate groups are a component of ATP.

Visualize the structural formula of each of the following hydrocarbons. Which hydrocarbon has a double bond in its carbon skeleton?

c2h4

Citric acid makes lemons taste sour. Which of the following is a functional group that would cause a molecule such as citric acid to be acidic?

carboxyl (The carboxyl group can release a hydrogen ion when in solution.)

These molecules are _____.

cis trans isomers

Which of these functional groups is characteristic of alcohol?

d. (Hydroxyl groups are characteristic of alcohol.)

Cis-trans isomers (geometric isomers) are molecules that _____.

differ in the arrangement of their atoms about a double bond

Which of these groups is characteristic of thiols?

e. Sulfhydryl thiols are characterized by the presence of a sulfhydryl group

Molecules that have the same chemical formula (same numbers of each atom) but different three-dimensional shapes are called _____.

isomers (Isomers of carbon compounds can arise in several different ways.)

An atom of iron has the atomic number 26. This means that

it has 26 protons and 26 electrons.

This pair of molecules are _____.

not isomers ( because they have different molecular formula)

What functional group is commonly used in cells to transfer energy from one organic molecule to another? See Concept 4.3

phosphate (The addition and release of phosphate groups to and from ADP and ATP is how cells store chemical energy and expend it to accomplish work.)

An atom has four electrons in its valence shell. What type(s) of covalent bonds is it capable of forming with oxygen?

single and double bonds

Based on the electron configuration of the elements below, which would exhibit a chemical behavior most like that of oxygen? C , O , H,N,S,P where the upper index is atomic mass and the lower index is atomic number. Based on the electron configuration of the elements below, which would exhibit a chemical behavior most like that of oxygen? , where the upper index is atomic mass and the lower index is atomic number. carbon nitrogen sulfur phosphorus

sulfur

Variations in the reactive properties of different organic molecules are most closely associated with _____. See Concept 4.3

the presence or absence of functional groups (Functional groups are the most common participants in chemical reactions.)

Organic chemistry is currently defined as

the study of carbon compounds