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