Flashcards in Unit 2 Exam (Chapters 5 and 27) Deck (210):
All living things are made up of four classes of large biological molecules. Those four are
carbohydrates, lipids, proteins, and nucleic acids
Within cells, small organic molecules are joined together to form
are large molecules composed of thousands of covalently connected atoms.
Carbohydrates, lipids, proteins, and nucleic acids.
Molecular structure and function are
is a long molecule consisting of many similar building blocks.
Ex. like 4 expo markers being put together and connected at each end making a long stick.
are the small building-block molecules that combine and form polymers.
Ex. one expo marker
Three of the four classes of life's organic molecules are polymers. These three are
A dehydration reaction
occurs when two monomers bond together through the loss/production of a water molecule.
Removing water causes things to build up and stick together.
Polymers are disassembled to monomers by
a reaction that is essentially the reverse of the dehydration reaction.
Adding water causes it to break a part. The breaking apart happens after you add a water molecule.
Each cell has thousands of different
Macromolecules vary among cells of an organism, vary more within a species, and
vary even more between species
An immense variety of polymers can be built from a small set of
This is because of arrangement. Its like the alphabet and the 26 letters that create millions of different words.
include sugers and the polymers of sugars.
The simplest carbohydrates are
monosaccharides, or single sugars.
Carbohydrate macromolecules are
polymers composed of many sugar building blocks
Sugars- Names end in
have molecular formulas that are usually multiples of CH2O
C and O will always have the same amount.
H is always double of what C and O are.
Glucose (C6H12O6) is
the most common monosaccharide.
-Vary in length, location of carbonyl, isomers
Monosaccharides are the
-Major fuel for cells (food, energy)
-Raw material for building molecules (use them as bricks to make other molecules)
Though often Monosaccharides are drawn as linear skeletons,
aqueous solutions many sugars form rings.
When wet, they will form rings.
When dry, they form straight lines.
A disaccharide is
formed when a dehydration reactions joins two monosaccharides
The covalent bond that joins two monosaccharides and forms a disaccharide is called a
do not need to know or worry about!
Three Disaccaride structures
Glucose + Fructose = Sucrose
Glucose + Glucose = Maltose
Glucose + Galactose = Lactose
Glucose + Fructose =
Glucose + Glucose =
Glucose + Galactose =
Dehydration reaction in the synthesis of
(and in the synthesis of Sucrose as well)
the polymers of sugars
they have storage and structural roles
Polysaccharides structure and function are determined by its
sugar monomers and the positions of glycosidic linkages
Starch, a polysaccharide of plants, consists entirely of glucose monomers.
lots of glucose.
1-4 a(alpha) linkages
a helical shape.
Plants make starch made up of a alpha glucose
Plants store surplus starch as granules within chloroplasts and other plastids
a simple starch.
a complex starch.
a few branch points.
ex. brown rice, whole grains
Starch structure and function
structure- plants-- alpha glucose
is a polysaccharide in animals.
all glucose monomers.
Humans and other vertebrates store glycogen mainly in liver and muscle cells.
Stores only last 24 hours.
(how we store our energy)
Glycogen structure and function
structure- animals- glucose
The polysaccharide cellulose is a major component of the tough wall of plant cells.
made up of hundreds of glucose that only plants make.
like starch, cellulose is a polymer of glucose, but the glycosidic linkages differ.
The difference is based on two ring forms for glucose: alpha (a) and beta (B).
They look a little different.
a (alpha) glucose
B (beta) glucose
Cellulose Structure and Function
structure- plants- B (beta) glucose
Function- structure- it makes cell walls
polymers with a (alpha) glucose are
polymers with B (beta) glucose are
In straight structures of polymers/polysaccharides
H atoms on one strand can bond with OH groups on other strands (hydrogen bonds).
Parallel cellulose molecules held together this way are grouped into microfibris which form strong building materials for plants.
Enzymes that digest starch by hydrolyzing a (alpha) linkages can't
hydrolyze B (beta) linkages in cellulose
Cellulose in human food passes through the
digestive tract as insoluble fiber
Some microbes use
enzymes to digest cellulose
Many herbivores, from cows to termites, have
symbiotic relationships with those microbes that use enzymes to digest cellulose.
We can not digest
B (beta) linkages
Chitin, another structural polysaccharide, is found in the exoskeleton of anthropods.
(the crunch sound when you step on bugs?)
Chitin also provides
structural support for the cell walls of many fungi
don't worry about? see picture on slide?
the one class of large biological molecules that do NOT form polymers
The unifying feature of lipids is having
little or no affinity for water.
None of lipids like water.
Lipids are hydrophobic because
they consist mostly of hydrocarbons, which form nonpolar covalent bonds
Most biologically important lipids
Lipids do not have any
Lipids bond is called an
ester linkage bond
are constructed from two types of smaller molecules: glycerol and fatty acids
Glycerol is a
three-carbon alcohol with a hydroxyl group attached to each carbon
A fatty acid consists of
a carboxyl group attached to a long carbon skeleton
Fats separate from water because
water molecules form hydrogen bonds with each other and exclude the fats
in a fat, three fatty acids are joined to a glycerol by an ester linkage, creating a triacylglycerol or triglyceride.
ester linkage bond is like a
Bond between glycerol and 3 fatty acids is called an
Fatty acids vary in length (number of carbons) and in the number and
locations of double bonds
(not al the same)
Saturated Fatty acids
have the maximum number of hydrogen atoms possible and no double bonds
Unsaturated fatty acids
have one or more double bonds (cis)
all single bonds.
Solid at room temperature.
Bad for you.
They are packed together densely
double bond in it somewhere which creates a kink.
liquid at room temperature.
you want to eat these.
they are good for you.
Fats made from saturated fatty acids are called
saturated fats, and are solid at room temperature.
Most animal fats are saturated
Fats made from unsaturated fatty acids are called
unsaturated fats or oils, and are liquid at room temperature.
Plant fats and fish fats are usually unsaturated
A diet rich in saturated fats contributes to
cardiovascular disease through plague deposits
the process of converting unsaturated fats to saturated fats by adding hydrogen
Hydrogenating vegetable oils also creates unsaturated fats with
trans double bonds
These Trans fats may contribute more than
saturated fats to cardiovascular disease.
the body has no way of processing these.
really bad for us.
death if eat them
Certain unsaturated fatty acids are not
synthesized in the human body.
these must be supplied in the diet.
these essential fatty acids include the omega-3 fatty acids, required for normal growth, and thought to provide protection against cardiovascular disease.
(fish oils is where we get them)
the major function of fats is energy storage.
Humans and other mammals store their fat in
Adipose tissue also cushions
vital organs and insulates the body
Fats structure and function
structure- glycerol + 3 fatty acids [saturated, unsaturated, trans fat]
function- energy storage, cushion organs
phospholipid is made up of
two fatty acids
a phosphate group.
In a phospholipid, the two fatty acid tails are
hydrophobic, but the phosphate group and its attachments form a hydrophilic head
When phospholipids are added to water, they self-assemble into a bilayer, with the hydrophobic tails
pointing toward the interior.
this is important because it relates to the function.
The structure of phospholipids results in
a bilayer arrangement found in cell membranes.
all cell membranes are made up of
phospholipids are the major component of all cell membranes
Phospholipids structure and function
structure- a glycerol, 2 fatty acids, and a phosphate group
function- cell membranes
steroids are lipids characterized by a carbon skeleton consisting of four fused rings
cholesterol, an important steroid, is a component in animal cell membranes.
Many hormones (Estrogen, testosterone) are synthesized from cholesterol. (steroids).
Although cholesterol is essential in animals,
high levels in blood contribute to cardiovascular disease.
Need cholesterol so we can
build cell membranes and have steroids (estrogen, testosterone)
Steroids structure and function
structure- four fused rings
function- cell membranes/hormones
Proteins account for more than
50% of the dry mass of most cells.
(This is important!!!)
Proteins have 8 functions
2. Defense against foreign substances
Proteins can do a
wide variety of jobs
speed up reactions.
Function- selective acceleration of chemical reactions.
example: digestive enzymes catalyze the hydrolysis of bonds in food molecules
function- protect against disease
example: antibodies inactivate and help destroy viruses and bacteria
function- storage of amino acids
example: casein, the protein of milk, is the major source of amino acids for baby mammals. Plants have storage proteins in their seeds. Ovalbumin is the protein of egg white, used as an amino acid source for the developing embryo
function- transport of substances
examples: hemoglobin, the iron-containing protein of vertebrate blood, transports oxygen from the lungs to other parts of the body. other proteins transport molecules across cell membranes.
function- coordination of an organism's activities
example: insulin, a hormone secreted by the pancreas, causes other tissues to take up glucose, thus regulating blood sugar concentration
function- response of cell to chemical stimuli
example: receptors built into the membrane of a nerve cell detect signaling molecules released by other nerve cells
Contractile and Motor proteins
examples: motor proteins are responsible for the undulations of cilia and flagella. Actin and myosin proteins are responsible for the contraction of muscles
examples: keratin is the protein of hair, horns, feathers, and other skin appendages. Insects and spiders use silk fibers to make their cocoons and webs, respectively. Collagen and elastin proteins provide a fibrous framework in animal connective tissues.
are a type of protein that acts as a catalyst to speed up chemical reactions
perform their functions repeatedly, functioning as workhorses that carry out the processes of life. (they can do the same job over and over again and never run out)
Never used up, not changed in a reaction.
Names end in --ase
All proteins have a
unique 3 dimensional shape
Polypeptides are unbranched polymers built from the same set of 20 amino acids.
structure of an amino acid
A protein is a
biologically functional molecule that consists of one or more polypeptides.
Amino acids link together and form
Amino acids are a type of
Amino acids are
organic molecules with carboxyl and amino groups
Amino acids differ in their
properties due to differing side chains, called R groups
Cells use 20 amino acids to make
thousands of proteins.
they all have an amino group, carboxyl group, but the one different thing is the
R group (side chain)
Amino acids are linked by
between a carboxyl terminus and amino terminus
A polypeptide is a
polymer of amino acids
Polypeptides range in length from a
few to more than a thousand monomers
Each polypeptide has a unique linear sequence of amino acids, with
a carboxyl end (C-terminus) and an amino end (N-terminus)
a dehydration reaction occurs when
a new peptide bond is forming?
Polypeptide does NOT equal a
A functional protein consists of
one or more polypeptides precisely twisted, folded, and coiled into a unique shape
Ribbon models and space filling models can
depict a protein’s conformation
The sequence of amino acids determines a protein’s
A protein's structure determines its
Four levels of protein structure
The primary structure of a protein is its
unique sequence of amino acids
Secondary structure, found in most proteins, consists of
coils and folds in the polypeptide chain.
a (alpha) helices and B (beta) pleated sheets
Tertiary structure is
determined by interactions among various side chains (R groups)
Quaternary structure results when a
protein consists of multiple polypeptide chains
the sequence of amino acids in a protein, is like the order of letters in a long word.
telling how to build the molecule. the names.
Primary structure is determined by
inherited genetic information
The coils and folds of secondary structure result from
from hydrogen bonds between repeating constituents of the polypeptide backbone
(why/how they form)
Typical secondary structures
a coil called an a (alpha) helix
a folded structure called a B (beta) pleated sheet
Tertiary structure is determined by
interactions between R groups, rather than interactions between backbone constituents
Hydrophobic R groups will orient toward
Hydrophilic R groups will orient toward
Interactions between R groups include
van der Waals interactions
Strong covalent bonds called disulfide bridges may
reinforce the protein’s structure
At the point during the tertiary structure level,
many proteins are functionally complete, but not all
Quaternary structure results when
two or more polypeptide chains form one macromolecule
Collagen is a
fibrous protein consisting of three polypeptides coiled like a rope
Hemoglobin is a
globular protein consisting of four polypeptides: two alpha and two beta chains
During quaternary structure,
multiple subunits (polypeptides) have to come together
A slight change in primary structure can affect a protein’s
structure and ability to function
Sickle-cell disease, an inherited blood disorder, results from
a single amino acid substitution in the protein hemoglobin.
(only 1 amino acid is wrong)
In addition to primary structure,
physical and chemical conditions can affect structure
Alterations in pH, salt concentration, temperature, or other environmental factors can cause a protein to
This loss of a protein’s native structure is called
(this is really bad)
A denatured protein is biologically inactive
It is hard to predict a protein’s structure from its
Most proteins probably go through several stages on their way to a stable structure
protein molecules that assist the proper folding of other proteins
proteins, makes sure they fold correctly.
Diseases such as Alzheimer’s, Parkinson’s, and mad cow disease are associated with
store, transmit, and help express hereditary information
The amino acid sequence of a polypeptide is programmed by a unit of inheritance called a
Genes are made of DNA, a
nucleic acid made of monomers called nucleotides
Genetic information flows
DNA >> RNA >> Protein
(biology's central dogma)
two types of nucleic acids
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
Function of DNA
DNA provides directions for its own replication
DNA directs synthesis of messenger RNA (mRNA)
Function of RNA
mRNA, controls protein synthesis (helps make proteins)
Protein synthesis occurs on ribosomes
Nucleic acids are polymers called
Nucleic acid monomers
Each polynucleotide is made of monomers called
Nucleic Acids/ Nucleotides structure
each nucleotide consists of
a nitrogenous base
a pentose sugar
and one or more phosphate group
The portion of a nucleotide without the phosphate group is called a
Two families of nitrogenous bases
cytosine, thymine, and uracil.
have a single six-membered ring.
adenine and guanine.
have a six-membered ring fused to a five-membered ring.
In DNA, the sugar is
In RNA, the sugar is
Nucleotide polymers are linked together to build a
Adjacent nucleotides are joined by covalent bonds that form between the
—OH group on the 3' carbon of one nucleotide and the phosphate on the 5' carbon on the next.
These links create a backbone of sugar-phosphate units with nitrogenous bases as appendages
The sequence of bases along a DNA or mRNA polymer is
unique for each gene
RNA molecules usually exist as
single polypeptide chains
DNA molecules have
two polynucleotides spiraling around an imaginary axis, forming a double helix
In the DNA double helix, the two backbones run in opposite 5'→ 3' directions from each other, an arrangement referred to as
One DNA molecule includes
The nitrogenous bases in DNA pair up and
form hydrogen bonds: adenine (A) always with thymine (T), and guanine (G) always with cytosine (C)
Adenine (A) always pairs up with
Guanine (G) always pairs up with
The nitrogenous bases in DNA pairing up is called
complementary base pairing
Complementary pairing can also occur between
two RNA molecules or between parts of the same molecule
thymine is replaced by uracil (U) so A and U pair
Guanine and cytosine
Adenine and Uracil
Adenine and Thymine
Guanine and Cytosine
The linear sequences of nucleotides in DNA molecules are passed from
parents to offspring
Two closely related species are more similar in DNA than are
more distantly related species
Molecular biology can be used to assess
Higher levels of organization result in the
emergence of new properties.
working way up levels of hierarchy