Ch.5: Macromolecules Flashcards
Living things are made up of four classes of macromolecules:
Carbohydrates, lipids, protein, and nucleic acid
are large molecules composed of thousands of covalently connected atoms
macromolecules
is a long molecule consisting of many building blocks
Monomers
polymers
Three of the four classes of life’s organic molecules are polymers:
Carbohydrates, proteins and nucleic acid
Monomers are bonded together via a
condensation reaction/ dehydration reaction
Polymers are disassembled into monomers by XXXX a reaction that is essentially the reverse of the dehydration reaction
Hydrolysis
Description of Carbohydrates:
monosachrides and disaccharides and polysaccharide glucose, sucrose, starch simple sugar major fuel for cells raw material for building molecules
storage and structure
polysaccharide
a storage polysaccharide of plants, consists entirely of glucose monomers
starch
is a storage polysaccharide in animals
glycogen
is a major component of the tough wall of plant cells
XXXX is not easily digested
XXXXX in human food passes through the digestive tract as insoluble fiber
Starch and XXXXX are both polymers of glucose, but their bonds differ.
Cellulose
another structural polysaccharide, is found in the exoskeleton of arthropods
XXXXX also provides structural support for the cell walls of many fungi
Chitin
Describe Lipids:
do not form polymers
have little or no affinity for water
Nonpolar
The most biologically important lipids are fats, phospholipids, and steroids*
are actually alcohols but alcohols behave like lipids
Steroids
Fats are constructed from two types of smaller molecules
glycerol and fatty acids
a three-carbon alcohol with a hydroxyl group attached to each carbon
Glycerol
consists of a carboxyl group attached to a long carbon skeleton
fatty acids
Saturated fatty acids have
no double bonds
the maximum number of hydrogen atoms possible
Unsaturated fatty acids have
one or more double bonds
The major function of fats is
to store energy
two fatty acids and a phosphate group are attached to glycerol
The two fatty acid tails are hydrophobic
The phosphate group and its attachments form a hydrophilic head
These properties make it a wonderful material to form membranes
phospholipid
lipids characterized by a carbon skeleton consisting of four rings
steroids
an important component in animal cell membranes
Maintains correct membrane fluidity
However, high levels in the blood may contribute to cardiovascular disease
cholesterol
Describe protein:
account for more than 50% of the dry mass of most cells
Function:
support, storage, transport, cellular communications, movement, and defense against foreign substances
A type of protein that acts as a catalyst to speed up chemical reactions
XXXXX can perform their functions repeatedly, functioning as workhorses that carry out the processes of life
XXXXX don’t change the net yield of a chemical reaction
Enzymes
are polymers built from 20 amino acids linked by peptide bonds
polypeptides
Amino acids differ in their properties due to differing side chains,
R group
Central skeleton of all 20 AA’s is the same
carboxyl and amino group
A functional protein consists of
one or more polypeptides, twisted, folded, and coiled into a unique shape
Primary structure:
sequence of amino acids
proteins do everything except genetic encoding
determined by DNA
Secondary Structure:
hydrogen bonding takes place between the strands, rippling
Tertiary Structure:
several secondary structures linked together
Quaternary Structure:
more than one polypeptide
Alterations in pH, salt concentration, temperature, or other environmental factors can cause a protein to unravel
This loss of a protein’s native structure is called
Denaturation
two types of nucleic acids
DNA and RNA
provides directions for its own replication
XXX directs synthesis of messenger RNA (mRNA) and, through mRNA,
DNA
aids in protein synthesis
RNA
Nucleic acids are polymers of
nucleotides
Each nucleotide consists of a
Nitrogenous base
Pentose sugar (5 Carbon)
Phosphate group
A DNA molecule is two polynucleotides spiraling around an imaginary axis, forming a
double helix
In the DNA double helix, the two backbones run in opposite directions from each other, an arrangement referred to as
antiparallel
The nitrogenous bases in DNA pair up and form hydrogen bonds:
Which allows DNA to replicate itself
adenine (A) always with thymine (T), and guanine (G) always with cytosine (C)
Pyrimidines include:
Thymine, Cytosine and Uracil
Purines include
Adenine and Guanine
