Biology Chapter 2
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Biology Chapter 2
bio chapter 2
Living this are a collection of?
Atom and molecules
Atoms are what?
Smallest functional units of matter
form all chemical substance
cannot be further broken down into other substances by ordinary chemical or physical means
Each specific type of atom is a?
What is the 3 subatomic particles?
found in nucleus
same number as electrons
# of atomic number
numbers can vary
found in orbitals
same number of protons
What charge does atoms have?
No electric charge
organized by atomic number
rows correspond to number of electon shells
columns left to right tell the number of electrons inthe outer shell
elements within a column are similar b.c they have the same outer shells and have similar chemical bonding properties.
protons and neutrons = in mass
hydrogen atom has an atomic mass of 1
measurement for atomic mass
1 (d)= 1/12 the mass of carbon atom
carbon has an atomic mass of 12 daltons
1 mole of any element contains the same number of atoms- 6.022x10^23
Multiple forms of an element that differ in the number of neutrons
atomic masses are averages of the wieghts of different isotopes of an element.
Which elements are important in biology?
95% of atoms in living organisms
H and O in water
N in proteins
C in building block of all living matter
what percentage does mineral elements have in HOCN
less than 1%
What percentage does trace elements have in HOCN
less than 0.015
2 or more atoms bonded together
Chemical symbols of elements found in a molecule
subscript indicates how many of each atom are present
Molecule composed of two or more elements
Types of chemical bonds
atoms share pair of electrons
strongest of all chemical bonds
Single bond H-F
Double Bond O=O
Atoms are stable when their outer shell is full
outer shell fills with 8 electrons
exception:hydrogen, fills its outer shell with 2 electrons.
Attract an electron from another atom
In a bond, electrons are more likely to be closer to the atom with higher electonegativity-polar covalent bond.
Chemical structure of water
electrons are more electronegative oxygen atom rather than less electronegative hydrogen atoms
molecules has partial negative charge region and a partial positive charge region
Weak polar bonds
Hydrogen atoms from one molecue is attracted to an electronegative atom from another molecule
(dash or dotted line)
Holds DNA stands together
atom or molecule that has gained or lost one or more electrons
net electric charge
have a charge if they gain or loose electrons
Net negative charge
What are the 2 net electric charge of Ionic bonds
How do ionic bonds occurs
Cations binds to an anion
Properties of water
adhesion/ surface tension
High boiling point
Density is lower when frozen
High heat capacity
Participates in reactions
solutions is made up of?
solutes- substances dissolved in solvent
aqueous solution has what solvent
water is the solvent
ions and molecules contain what bond for it dissolve in water?
dissolve in water
ions and molecules that contain polar covalent bonds
dont easily dissolve in water
nonpolar molecules like hydrocarbon
polar or ionized regions at one or more sites
nonpolar regions at other sites
Properties of water depends on
concentratino of dissolved solute
what happens when you add solutes to water?
lowers freezing point below 0 degrees C
raises its boiling point above 100C
Important function in living organisms
Participates in chemical reactions (hydrolysis or dehydration)
provides force or support
remove toxic waste components
cohension and adhesion
high heat capacity
Pure water has the ability to ionize to a very small extent to what 2 ions.
Hydrogen ions (H+)
hydroxide ions (OH-)
Acids are moelcules that release what in a solution?
a strong acid releases more H+ than a weak acid.
Bases lower what concentration?
H+ (base is an H+ acceptor)
others bind H+
pH=- log10 [H+]
acidic solution is where on ph scale?
Alkaline (bases) are where on PH?
Ph of a solution can affect?
shapes and function of molecules
rates of many chemicals reactions
ability of two molecules to bind to eachother
ability of ions or molecules to dissolve in water
keep a constant pH
acid base buffer system can shift to generate or release H+ to adjust for changes in pH
organic molecules contain Carbon
abundant in living organisms
biologically relevant macromolecules are large, complex organic molecules.
4 electrons in its outer shell
needs 4 more electrons to fill the shell
make up to four bonds (single or double)
form non-polar and polar bonds
nonpolar bonds are
poorly water soluble
more water soluble
oxygen occurs in two functional groups?
Both contibute to solubility of biomolecules
1 hydrogen paired with 1 oxygen atom
not highly reactive, but contribute to making molecules soluble in water.
Alcohol and sugars are "loaded" w/ them.
1 oxygen atom double bonded to C atom
contribute to making molecules water soluble.
sugars one group
ionize and dissociate into H+ and COO-
confer acidic properties to molecules
Basic and often become ionized to form a positive charged NH3+ group.
sulfhydryl and disulfide groups
Isomers 2 of them?
identical molecular formular, diffrent structures.
Contain the same atom but in diffrent bonding patterns
identical bonding relationships, but the spatial positiong of the atoms differs in the two isomers.
4 major type of biomolecules
many biomolecules are large polymers made up of repeating monomer subunits
Carbon, hydrogen and oxygen atoms
simples sugars and carbs
5 or 6 carbons are common
(C5H10O6) - pentoses-ribose
(C6H12O6)- hexose glucose
carbohydrates composed of two monosaccharids
joined by dehydration or condensation reaction
hydrolysis breaks them apart.
inability to cleave lactose into monosaccharids
monosaccharids linked together to form
engergy storage- startch, gylcogen
structural role- cellulose, chitin, glycosaminoglycans
Carbohydrate break down to release engergy and store it?
Hydrogen and carbon atoms composed
*nonpolar and very insoluble in water*
bonds glycerol to three fatty acids
dehydration or condensation reaction joins them together.
hydrolysis breaks them
3 carbon backbone (glycerol) attatches to a long fatty acid chain.
how is fat formed?
dehydration reaction in which fatty acids are added to glycerol
fatty acids 2 types?
saturated fatty acids
all carbons linked by single covalent bonds
solid at room temp.
contain one or more double bonds
1 double bond- momounsaturated
2 or more- polyunsaturated
liquids at room temp
polyunsat- more than one double bond.
unsaturated fat that are partially hydrogenated through an industrial process
different isomerization around double bond
more hazardous to the heart than saturated fats.
: crisco, margine
important for engergy storage
1g is twice as much energy as 1 gram of glycogen or starch.
provide structural in providing cushioning and insulation
glycerol, 2 fatty acids and phosphate groups
form membranes (building blocks)
four interconnected rings of carbon atoms
not water soluble
estrogen and testosterone differ slightly
important hormoes and signaling molecules
proteins are made up of?
common structre with variable R-group
20 amino acids
side chain determines structure and function
structure of amino acids.
R groups confer different prop to amino acids.
joined by dehydration/condensation reaction.
- peptide bond
proteins are madeup of 1 or more polypeptides
broken apart by hydrolysis
Primary- linear chain of amino acids
Secondary- alpha helices, beta sheets,
Tertiary- 3D arrangement of 2 elements
Quaternary- how multiple polyeptide chains interact with each other.
amino acids sequence
determined by genes
represented by either three-letter or one-letter code.
Alanine - Ala A
Tyrosine- Tyr Y
Glutamine- Gln Q
1 chain of amino acids is one polypeptide.
Chemical and physical interactons cause folding
Alpha helices and Beta sheets.
Random coiled regions
- unstructured regions not alpha=helix or beta= pleated sheets
Factors promoting protein folding and stability?
Hydrogen bonds- weak
ionci bonds- cation and anions that are attracted to each other
hydrophobic effect- like the same
van der waals forces- attractive forces occur between atoms that are optimal distances apart.
folding of secondary elements gives complex three dimensional shape
2 or more polypeptides
- protein subunits
- multimeric proteins
Protein - protein interactions
cellular processes involve steps in which two or more different proteins interact with each other
specific binding at surface
All information needed is stored in the sequence itself of the Primary structure of ribonucleases.
Protein misfolding causes several disease.
Prions are what type of proteins?
responsible for the storage, expression and transmission of genetic info.
- stores genetic info
- decodes dna information into instructions for building polypeptide chain
has other regulatory and strucural functions
Nucleotides are bulidng block of nucleic acids.
5 carbon sugar (ribosome or deoxyribose)
single or double ring of Carbon and nitrogen atoms- nitrogenous base
Nucleid Acid Structure
Dna is usllay found in dbl standed molecule.
RNA exists as a single bond.
complementary base pairing
ribose instead of deoxyribose
contains uracil in place of thymine
DNA VS RNA