BIOL 103 Ch. 3

Amino acids, the building blocks of proteins, have an amino group and a carboxyl group

Both of these are covalently bonded to a central, alpha carbon Also bonded to the central carbon is a hydrogen atom and some other chemical group symbolized by R

An example of similar compounds that differ only in functional groups is sex hormones

Male and female sex hormones differ only in functional groups. The differences cause varied molecular actions The result is distinguishable features of males and females

A nucleic acid polymer, a polynucleotide, forms from the nucleotide monomers when the phosphate of one nucleotide bonds to the sugar of the next nucleotide

The result is a repeating sugar-phosphate backbone with protruding nitrogenous bases

Each of the four lines in the formula for methane represents ________.

a pair of shared electrons.

A cell makes a large number of polymers from________.

a small group of monomers

By sharing electrons, carbon can ________. By doing so, it can branch in up to four directions.

bond to four other atoms

Carbon skeletons can be _______

branched or unbranched

Amino group—

composed of a nitrogen bonded to two hydrogen atoms and the carbon skeleton

Methyl group—

consists of a carbon bonded to 3 hydrogens

Carboxyl group—

consists of a carbon double-bonded to both an oxygen and a hydroxyl group

Hydroxyl group—

consists of a hydrogen bonded to an oxygen

Phosphate group—

consists of a phosphorus atom bonded to four oxygen atoms

The building blocks in a polymer are called _____.

monomers.

Sugar monomers are _________, such as glucose and fructose

monosaccharides

Hydrocarbons are _____molecules

non-polar

Molecules containing complex chains or rings of carbon are called

organic compounds

An example of similar compounds that differ only in functional groups is ______.

sex hormones

The ability to bond in four directions is called

tetravalence

Proteins are made from only _____ different amino acids, and DNA is built from just______ kinds of nucleotides

20 four

Nucleotides have three parts

A five-carbon sugar called ribose in RNA and deoxyribose in DNA A phosphate group A nitrogenous base

RNA also has A, C, and G, but instead of T, it has uracil (U)

Adenine (A) Cytosine (C) Guanine (G)

DNA nitrogenous bases are

Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

Two monosaccharides (monomers) can bond to form a disaccharide in a dehydration reaction

An example is a glucose monomer bonding to a fructose monomer to form sucrose, a common disaccharide

_______are hydrophilic and range from small sugar molecules (monomers) to large polysaccharides

Carbohydrates

There are four classes of biological molecules

Carbohydrates Proteins Lipids Nucleic acids

A chain of carbon atoms is called a _______

Carbon skeleton

Organic compounds contain carbon and inorganic compounds do not. T or F

F Inorganic compounds CAN contain carbon!!!!

i.e. Methane (CH4) is one of the simplest organic compounds

Four covalent bonds link four hydrogen atoms to the carbon atom

The carbon skeletons of monosaccharides vary in length

Glucose and fructose are six carbons long Others have three to seven carbon atoms

________(water-fearing) pertains to nonpolar molecules (or parts of molecules) that do NOT dissolve in water.

Hydrophobic

A protein can have four levels of structure

Primary structure Secondary structure Tertiary structure Quaternary structure

Amino acids are classified as hydrophobic or hydrophilic

Some amino acids have a nonpolar R group and are hydrophobic Others have a polar R group and are hydrophilic, which means they easily dissolve in aqueous solutions

Carbon, with attached hydrogens, can bond together in chains of various lengths. T or F?

T

Enzymes cannot CREATE or CAUSE rxns. T or F?

T

A polypeptide chain contains hundreds or thousands of amino acids linked by peptide bonds

The amino acid sequence causes the polypeptide to assume a particular shape The shape of a protein determines its specific function

The primary structure of a protein is its unique amino acid sequence

The correct amino acid sequence is determined by the cell's genetic information The slightest change in this sequence affects the protein's ability to function

An organic compound has unique properties that depend upon

The size and shape of the molecule and The groups of atoms (functional groups) attached to it

Two polynucleotide strands wrap around each other to form a DNA double helix

The two strands are associated because particular bases always hydrogen bond to one another

Sugar monomers are monosaccharides, such as glucose and fructose

These can be hooked together to form the polysaccharides

This causes kinks or bends in the carbon chain b/c the max. # of hydrogen atoms cannot bond to the carbons at the double bond

These compounds are called unsaturated fats because they have fewer than the maximum number of hydrogens

hydrophilic

These compounds are water soluble, which is a necessary prerequisite for their roles in water-based life.

Different compounds with the same molecular formula can be produced which are called_______

These structures are called isomers

Macromolecules are also called______

They are also called polymers because they are made from identical building blocks strung together

The four classes of biological molecules contain very large molecules

They are often called macromolecules because of their large size

Anabolic steroids are synthetic variants of testosterone that can cause a buildup of muscle and bone mass

They can be sold as prescription drugs and used to treat certain diseases They may also be abused with serious consequences, such as liver damage that can lead to cancer

Polysaccharides are polymers of monosaccharides

They can function in the cell as a storage molecule or as a structural compound

Lipids are hydrophobic compounds that are important in energy storage

They contain twice as much energy as a polysaccharide

Some fatty acids contain double bonds

This causes kinks or bends in the carbon chain b/c the max. # of hydrogen atoms cannot bond to the carbons at the double bond

Amino acid monomers are linked together to form polymeric proteins

This is accomplished by an enzyme-mediated dehydration reaction This links the carboxyl group of one amino acid to the amino group of the next amino acid

Carbonyl group—

a carbon linked by a double bond to an oxygen atom

Monomers are linked together to form polymers through _____, which remove water.

dehydration reactions

All biological reactions of this sort are mediated by ____, which speed up chemical reactions in cells

enzymes

One of the great advantages of carbon is its ability to ______.

form up to four bonds

A _______ affects a biological molecule's function in a characteristic way.

functional group

Methane and other compounds composed of only carbon and hydrogen are called ______.

hydrocarbons

Polymers are broken apart by ______, the addition of water

hydrolysis

Compounds containing functional groups are ______ (water-loving).

hydrophilic

The monomers used to make polymers are _____.

universal