chapter 5 Flashcards
dehydration reaction
occurs when two monomers bond together through the loss of a water molecule;
Hydrolysis
Polymers are disassembled to monomers by hydrolysis, a reaction that is essentially the reverse of the dehydration reaction
Monosaccharides
single, simple sugars
Disaccharides
composed of two covalently bonded simple sugars
Polysaccharides
polymers composed of many covalently bonded sugar monomers
What is cellulose?
A structural polysaccharide in plants
Which organisms produce cellulose?
Plants
How is cellulose different from starch?
Cellulose has indigestible beta glycosidic linkages; starch has easily broken alpha glycosidic linkages
What is cellulose’s function: a) in plants, b) in animals?
a) give structure to plant cell walls b) Dietary fiber
What monosaccharide do we obtain from hydrolysis of starch?
Glucose (C6H12O6)
Fats
energy storage, constructed from two types of smaller molecules: glycerol and fatty acids
Phospholipids
make cell membranes
Steroids
responsible for cell membrane rigidity and hormone production
Saturated fats
have no double bond in fatty acids, are solid at room temperature, and generally come from animal products
Unsaturated fats
have double bonds in fatty acids, are liquid at room temperature, and generally found come from plant products
Structure of phospholipids
two fatty acids and a phosphate group are attached to glycerol; The two fatty acid tails are hydrophobic, but the phosphate group and its attachments form a hydrophilic head;
Function of phospholipids
serve as the primary component of cell membranes
Structure of steroids
characterized by a carbon skeleton consisting of four fused rings
Function of steroids
to maintain membrane fluidity and as hormones
How do steroids differ from other fats?
Have a fused ring structure instead of fatty acids
What are some purposes of cholesterol?
maintain membrane fluidity and as precursor to hormones
What are some major functions of proteins?
structural support, storage, transport, cellular communications, movement, and defense
Describe the structure of an amino acid.
organic molecules with carboxyl and amino groups
What does the ‘R’ group on an amino acid determine?
Different properties of amino acids (polar, non-polar, ionic – acidic or basic)
Primary level of protein organization
the sequence of amino acids in a protein, is like the order of letters in a long word; Primary structure is determined by inherited genetic information
Secondary level of protein organization
The coils and folds resulting from hydrogen bonds between repeating constituents of the polypeptide backbone; Typical secondary structures are a coil called a helix and a folded structure called a pleated sheet
Tertiary level of protein organization
determined by interactions between R groups; Interactions include hydrogen bonds, ionic bonds, hydrophobic interactions, and van der Waals interactions; Strong covalent bonds called disulfide bridges may reinforce the protein’s structure
Quaternary level of protein organization
two or more polypeptide chains form one macromolecule
DNA
deoxyribose sugar, double stranded, thymine instead of uracil
RNA
ribose sugar, single stranded, uracil instead of thymine
What are the 5 nitrogenous bases?
Adenine, guanine, cytosine, thymine, uracil
Which bases are complementary between a) DNA strands, b) DNA and RNA strands?
a) adenine and thymine, guanine and cytosine, b) Adenine and uracil, guanine and cytosine
Macromolecule
large molecules composed of thousands of covalently connected atoms
Monomer
small building-block molecules that bond together to form polymers
Polymer
long molecule consisting of many similar building blocks (monomers)
Phosphate
PO4
enzyme
catalytic protein
catalyst
substance that speeds up chemical reactions
polypeptide
unbranched polymers built from amino acids
polynucleotides
nucleic acid polymers
purine
(adenine and guanine) have a six-membered ring fused to a five-membered ring
pyrimidine
(cytosine, thymine, and uracil) have a single six-membered ring
denaturation
breakdown of the secondary, tertiary, or quaternary structure of proteins
double helix
two polynucleotides spiraling around an imaginary axis
