biology EXAM #2 pt.2 Flashcards
Macromolecules and Polymers :
-Are…
examples:
-Are…
For example:
- large molecules composed of smaller molecules
Carbohydrates, lipids, proteins, nucleic acids
-complex in their structures
one hemoglobin molecule = thousands of covalently connected atoms, two polypeptide chains making one protein (quaternary structure)
Most macromolecules are ________, built from _____
-polymers
-monomers
Polymer =
a long molecule consisting of many similar building blocks called monomers
Three of the classes of life’s organic molecules are
polymers formed from a specific set of monomers
examples
polymers
monomers
-carbohydrates, protein, nucleic acid
-monosaccharide, amino acid, nucleotide
Although organisms share:
, each organism is :
An immense variety of polymers can be built from a:
-the same limited number of monomer types
-unique based on the arrangement of monomers into polymers
-small set of monomers
four important classes of biological molecules
three are:
one is:
-macromolecules: -carbohydrates, proteins, nucleic acids,
-not polymer or macromolecules: lipids
what are they made of:
-carbohydrates (starch):
-protein:
-nucleic acids:
- glucose
-amino acids
-nucleotide
These processes are facilitated by ________, which are:
enzymes
-specialized protein molecules that speed up the chemical reactions
Monomers
form what with what bond and how?
-by means of covalent bonds, form larger molecules or polymers by condensation reactions or dehydration reactions
Polymers can disassemble by ________ - ____ _____ = for example in digestion, it is assisted by ____ (i.e. lactose dehydrogenase, pancreatic lipases)
-Hydrolysis- needs water
-enzymes
A cell has thousands of :
Macromolecules vary among cells of an organism, vary more within a species, and vary even more between species
A huge variety of polymers can be built from
-different macromolecules
-a small set of monomers
Carbohydrates serve as
Carbohydrates include both :
-fuel and building material, structure, cell to cell recognition
-simple monosaccharides or simple sugars and their macromolecules or polysaccharides (polymers)
Monosaccharides:
-what is it?
-what functional group
- simplest sugars usually multiples of CH2O.
-Carbonyl as the functional group >C=O, and multiple hydroxyl groups –OH
Sugars can be divided into:
and this depends on:
-May be of two classes:
aldoses (aldehyde sugars) tiene el c=o diagonal
ketoses (ketone sugars,), tiene el c=o recto paralelo
-depending on the location of the carbonyl group
Sugars are also classified according to the:
length of their carbon skeletons:
hexoses, pentoses, trios.
sugars
first point of variation
second point
A third point of variation is the:
-position of the carbonyl group
-length of their carbon skeleton
- spatial arrangement around asymmetric carbons
Monomers:
can be used as…
can be converted..
can be combined…
Can be used for fuel
Can be converted into other organic molecules
Can be combined into polymers
Monosaccharides
Though often drawn as linear skeletons, in aqueous solutions…
many sugars form rings
Disaccharides:
double sugars - covalent bond called glycosidic linkage
dehydration (condensation) reaction:
1,4 linkages through dehydration reaction
3 common disaccharides
a. maltose = glucose + glucose = brewing beer
b. lactose = glucose + galactores = milk
c. sucrose = glucose + fructose = table sugar
Dehydration reaction in the synthesis of maltose. The bonding of ___ ___ ____ forms maltose. The glycosidic link joins _______________________________. Joining the glucose monomers in a different way would result in a different disaccharide.
-two glucose units
- the number 1 carbon of one glucose to the number 4 carbon of the second glucose
Dehydration reaction in the synthesis of sucrose. Sucrose is _________________________. Notice that fructose, though a hexose like glucose, forms a five-sided ring.
- a disaccharide formed from glucose and fructose
The architecture and function of a polysaccharide are determined by
its sugar monomers and the positions of its glycosidic linkages
polysaccharides serve many roles in organisms
two types of polysaccharides
storage polysaccharides– providing sugar to cells – storage in plastids including chloroplasts
Structural polysaccharides : Building material for structures
storage polysaccharides–
two examples
- starch in plants (glucose monomers)
a)-alpha (starch) versus beta (cellulose) glucose
b)-amylose – simple form of starch: unbranched
c)-amylopectin – more complex form of starch – branched polymer with 1-6 linkages at branch points- glycogen– in animals (glucose monomers) more branches –storage in liver and muscle cells
Starch
it is the major…
plants store…
simplest form is…
It is the major storage form of glucose in plants.
Plants store surplus starch as granules within chloroplasts and other plastids
The simplest form of starch is amylose
glycogen
consists of…
it is the major…
stored mainly in…
what to do when the demand for sugar increases…
Consists of glucose monomers
Is the major storage form of glucose in animals
Glycogen is stored mainly in liver and muscle cells
Hydrolysis of glycogen in these cells releases glucose when the demand for sugar increases
Structural polysaccharides :
info-
two examples:
has…
major component of…
-Building material for structures
– straight never branched polysaccharide hydrogen bonding between the hydroxyl groups of C 3 and C 6 of other molecules lying paralleled to it
i. Cellulose- in plants
ii. Chitin – in arthropods and some fungi. – N- containing appendage. It is a polymer of glucose
Has different glycosidic linkages than starch
Is a major component of the tough walls that enclose plant cells
enzymes that digest starch by hydrolyzing a linkages can’t…
the cellulose in human food passes…
some microbes use…
many herbivores have…
Enzymes that digest starch by hydrolyzing α linkages can’t hydrolyze β linkages in cellulose
The 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 these microbes
starch is largely…
cellulose molecules are…
some hydroxyl groups can…
helical
are straight and unbranched
Some hydroxyl groups on the monomers of cellulose can hydrogen-bond with hydroxyls of parallel cellulose molecules
Cellulose is difficult to digest cows have…
microbes in their stomachs to facilitate this process
Another important structural polysaccharide is…
Is found in…
Can be used as…
it has a…
it forms the…
Chitin
the exoskeleton of arthropods (embedded in a layer of proteins)and many fungi (instead of cellulose for the cell wall)
surgical thread
nitrogen containing attachment
exoskeleton of arrthropods
main diff between starch and cellulose
*starches – more helical
*cellulose molecule- straight and never branched and the -OH group can h-bond with other –OH from other cellulose
Lipids are…
function:
are the one class that…
structure:
Are a diverse group of hydrophobic molecules (ie: fats, phospholipids and steroids)
Function – many , they vary: energy storage more than starch, cushions vital organs (kidney), insulation
Are the one class of large biological molecules that do not consist of polymers
Structure – two small molecules:
·glycerol – an alcohol with 3 C, each with a hydroxyl group (-OH)
·fatty acid -16-18 C chain with a carboxyl group ( OH-C=O) and a non polar C-H bond at the other end.
·Dehydration reaction forming an esther linkage. Share the common trait of being hydrophobic
Fat molecule or triacylglycerol
structure:
Structure: a single glycerol and usually three fatty acids bonded by esther linkages
Fatty acids
vary in the…
types of fat:
-Vary in the length and number and locations of double bonds they contain
Types of fat:
a.saturated (single bonded C atoms), the molecule can pack tightly side by side – most animal fat,
b. unsaturated (double bonded C atoms), plants and fishes, the cis double bonds prevent it from solidifying at room T.
Saturated fatty acids
Have the maximum number of…
Have no…
At room temperature…
Have the maximum number of hydrogen atoms possible
Have no double bonds
At room temperature, they are solid
Unsaturated fatty acids
Have one or more…
At room temperature they…
Have one or more double bonds
At room temperature they cannot solidify, so they are liquid
Fats made from saturated fatty acids are called…
Most animal fats are…
Fats made from unsaturated fatty acids are called…
Plant fats and fish fats are…
are called saturated fats and are solid at room temperature
saturated
are called unsaturated fats or oils and are liquid at room temperature
unsaturated
A diet rich in saturated fats may contribute to…
Hydrogenation is the process of…
Hydrogenating vegetable oils also creates…
These trans fats may contribute…
contribute to cardiovascular disease through plaque deposits
converting unsaturated fats to saturated fats by adding hydrogen
creates unsaturated fats with trans double bonds
contribute more than saturated fats to cardiovascular disease
Certain unsaturated fatty acids are not…
These must be…
These essential fatty acids include the….
The major function of fats is…
Humans and other mammals store their long-term food reserves in…
Adipose tissue also…
are not synthesized in the human body
supplied in the diet
include the omega-3 fatty acids, which are required for normal growth and are thought to provide protection against cardiovascular disease
is energy storage
in adipose cells
also cushions vital organs and insulates the body
phospholipids
have only…
have a…
When phospholipids are added to water…
At the surface of a cell, phospholipids are also arranged in a….
The phospholipid bilayer forms a…
Have only two fatty acids (the hydrophobic “tails”)
Have a phosphate group instead of a third fatty acid (the hyrophilic “head”)
When phospholipids are added to water, they self-assemble into double-layered sheets called bilayers
At the surface of a cell, phospholipids are also arranged in a bilayer, with the hydrophobic tails pointing toward the interior
The phospholipid bilayer forms a boundary between the cell and its external environment
steroids
Are…
Types of steroids vary in ____________. Cholesterol is…
Also found in…
A high level of cholesterol in the blood may contribute to-…
Are carbon skeleton of 4 fused rings
in functional group. Cholesterol is precursor of other steroid synthesis such as vertebrate sex hormones (testosterones, estradiol)
in cell membranes
contribute to cardiovascular disease.
emulsificaions
Fats are ________; they do not ______________________ and tend to form “__________” (think of oil and vinegar salad dressing)
Emulsifier breaks down…
Emulsifiers have a…
Fats are nonpolar; they do not dissolve in water and tend to form “globules” (think of oil and vinegar salad dressing)
Emulsifier breaks down the globules of fat into smaller droplets
Emulsifiers have a nonpolar end which attaches to the fat, and a polar end which interacts with water molecules so that the droplets can disperse
Proteins have…
account for…
Function: many –
Proteins have many structures, resulting in a wide range of functions.
-account for more than 50% of the dry mass of most cells
Function: many –
a.speed up chemical reactions,
b. structural support,
c.storage,
d. transport,
e. cellular communications,
f.movement,
g.defense against foreign substances.
8 types of proteins: name, function,example
enzymatic proteins: Selective acceleration of
chemical reactions. Example: digestive enzymes
defensive proteins: Protection against disease. Example: antibodies
storage proteins: 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.
transport proteins: Transport of substances. Example: Hemoglobin, the iron-containing protein of vertebrate blood, transports oxygen from the lungs to other parts of the body.
Hormonal proteins: 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.
Receptor proteins: 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: Movement. Example: Motor proteins are responsible for the undulations of cilia and flagella. Actin and myosin proteins are responsible for the contraction of muscles.
Structural proteins: Support. Example: 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.
Enzymes , perhaps most important..
Are a type of protein that…
Enzymes , perhaps most important proteins
Are a type of protein that acts as a catalyst, speeding up chemical reactions
Polypeptides are…
all proteins made up of-….
Are polymers of amino acids bonded by of peptide bonds
all proteins made up of one or more polypeptides of same 20 a.a. folded and coiled in a specific conformation.
Amino acids are…
Differ in their…
The R groups or side chains determine the…
___ different amino acids make up proteins
Are organic molecules possessing both carboxyl and amino groups
Differ in their properties due to differing side chains, called R groups
The R groups or side chains determine the characteristics of a particular a.a.
20 different amino acids make up proteins
amino acids
Types of side chains: (3)
Are linked by…
The sequence of amino acids determines…
A protein’s structure determines…
The function of a protein usually depends on …
a.polar – hydrophilic
b. Electrically charged:
i.acidic – negatively charged due to carboxyl group on side chain – dissociated at cell Ph
ii.basic – positively charged due to amine groups on side chain
c. nonpolar – hydrophobic
linked by peptide bonds
determines a protein’s three-dimensional structure
determines how it works
depends on its ability to recognize and bind to some other molecule
one protein = _____________________. Some are _____, other ____
The ___________________ determines its function.
The function depends on:
a.
b.
one protein = one or more polypeptides precisely twisted, folded and coiled into a molecular unique shape. Some are globular, other fibrous.
The conformation of a protein determines its function.
The function depends on
a.its ability to recognize and bind to a molecule, related to shape.
i.e: endorphins. ➔ Natural drug, morphine, heroin, and other opiate mimic endorphins because share similar shape thus fitting and binding in receptors in the brain.
Determining the Amino Acid Sequence of a Polypeptide
The amino acid sequences of polypeptides:
Were first determined…
Can now be determined…
Were first determined using chemical means
Can now be determined by automated machines
Four levels of protein structure
Primary structure: is the unique sequence of amino acids in a polypeptide.
Secondary structure: is the folding or coiling of the polypeptide into a repeating configuration. Includes the α helix and the β pleated sheet and random coils
Tertiary structure: is the overall three-dimensional shape of a polypeptide. Results from interactions between amino acids and R groups
Quaternary structure: is the overall protein structure that results from the aggregation of two or more polypeptide subunits (collagen, hemoglobin)
Sickle-cell disease
Results from…
capacity…
Results from a single amino acid substitution in the protein hemoglobin
capacity to carry oxygen is reduced
protein conformation
Depends on the…
In addition to primary structure,
Alterations in…
This loss of a protein’s native structure is called…, which is…
A __________ protein is…
Depends on the physical and chemical conditions of the protein’s environment
physical and chemical conditions can affect structure
Alterations in pH, salt concentration, temperature, or other environmental factors can cause a protein to unravel
is called denaturation, which is when a protein unravels and loses its native conformation
A denatured protein is biologically inactive
The cellular environment may affect…
It may….
a)
b)
c)
Some denaturing agents:
Turn ________________, or may disrupt…
Example:
affect protein conformation.
It may denature it which inactivates it…
a) heat
b) pH
c) salt concentration
Some denaturing agents:
Turn hydrophilic ends outward, or may disrupt H-bonds, ionic bonds, disulfide bridges thus changing shape of protein
Example: Organic solvents (ether, chloroform)
Most proteins probably go through…
Chaperonins are…
Steps of Chaperonin
Action:
1.
2.
3.
several intermediate states on their way to a stable conformation
Are protein molecules that assist in the proper folding of other proteins
- An unfolded poly- peptide enters the cylinder from one end.
- The cap attaches, causing the cylinder to change shape in such a way that it creates a hydrophilic environment for the folding of the polypeptide.
- the cap comes off, and the properly folded protein is released.
Nucleic acids store and transmit…
Genes_
-Are
-Program
-Are made of
There are two types of nucleic acids:
Nucleic acids exist as…
Each polynucleotide consists of…
Nucleic acids store and transmit hereditary information
Genes:
-Are the units of inheritance
-Program the amino acid sequence of polypeptides
-Are made of nucleic acids
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
Nucleic acids exist as polymers called polynucleotides
consists of monomers called nucleotides
DNA
stores:
directs:
directs:
Stores information for the synthesis of specific proteins
Directs RNA synthesis
Directs protein
synthesis through
RNA
Nucleotide monomers - Are made up of…
Nucleoside =
There are two families of nitrogenous bases:
In DNA, the sugar is ________; in RNA, the sugar is ________
Are made up of nucleosides and phosphate groups
Nucleoside = nitrogenous base + sugar
-Pyrimidines (cytosine, thymine, and uracil)
have a single six-membered ring
-Purines (adenine and guanine) have a six-membered ring fused to a five-membered ring
In DNA, the sugar is deoxyribose; in RNA, the sugar is ribose
Nucleotide polymers are made up of…
The joining between nucleotides is called… , which consists of…
The sequence of bases along a nucleotide polymer is…
Cellular DNA molecules have …
The nitrogenous bases in DNA form …
Are made up of nucleotides linked by the–OH group on the 3´ carbon of one nucleotide and the phosphate on the 5´ carbon on the next
is called phosphodiester linkage, which consists of a phosphate group that links the sugars of two nucleotides.
is unique for each gene
have two polynucleotides that spiral around an imaginary axis forming a double helix
form hydrogen bonds in a complementary fashion (A with T only, and C with G only)
The DNA double helix consists of…
RNA, in contrast to DNA, is…
Complementary pairing can also occur between…
In RNA, ______ is replaced by ______ so…
While DNA always exists as a double helix, RNA molecules are…
Consists of two antiparallel nucleotide strands
is single stranded.
between two RNA molecules or between parts of the same molecule
In RNA, thymine is replaced by uracil (U) so A and U pair
are more variable in form
Molecular comparisons help biologists…
Remember, DNA is passed on from parent to offspring (with modifications) and closer related species share greater proportions of their DNA than do most distantly related species.
Help biologists sort out the evolutionary connections among species
Analyzing large sets of genes or even comparing whole genomes of different species is called _______:
-Once the structure of DNA and its relationship to amino acid sequence was understood, biologists sought to…
-The first chemical techniques for DNA sequencing were developed in the…
A similar analysis of large sets of proteins including their sequences is called _______
genomics
Once the structure of DNA and its relationship to amino acid sequence was understood, biologists sought to “decode” genes by learning their base sequences
- in the 1970s and refined over the next 20 years
-proteomics
It is enlightening to sequence the full complement of DNA in an organism’s genome
The rapid development of faster and less expensive methods of sequencing was a side effect of the…
Many genomes have been sequenced, generating…
It is enlightening to sequence the full complement of DNA in an organism’s genome
-of the Human Genome Project
generating reams of data
contributions of genomics and proteomics to biology
paleontology, evolution, medical science, conservation biology, species interactions.
