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Biology Exam 1

Terms in this set (86)

Properties of water
1. Exhibits polarity
2. Exists as a solid, liquid, or gas
3. High specific heat
4. Cohesion
5. High heat of vaporization
6. Adhesion
7. Principle solvent in organisms
Is water more dense as a solid or a liquid?
more dense in liquid form
Specific heat
amount of heat energy required to raise the temperature of 1g of substance by 1 degree celsius
Heat of vaporization
amount of heat energy required to convert 1g of liquid to gas
Cohesion
water molecules tend to stick together when placed under tension (due to H-bonds)
Adhesion
water molecules tend to stick to other particles or surfaces
-responsible for meniscus
Hydrophilic
compounds that dissolve in water(polar or ionic)
Hydophobic
compounds that repel water (nonpolar)
Acids
compounds that release hydrogen ions(H+) in solution
pH scale
[H+] expressed as #moles/liter
Bases
compunds that accepts hydrogen ions in solution
Buffers
chemical systems that include a weak acid a weak base
function is to resist large changes in pH
4 kinds of organic compounds
proteins, carbohydrates, lipids, and nucleic acids
Buffer system in our blood
carbonic acid/ bicarbonate base buffer system
helps to maintain blood pH b/ween 7.35-7.45
What percentage is water in living tissues?
70% water
Polymers
molecules composed of similar or identical repeating units or monomers linked together by covalent bonds
macromolecules, polypeptides, polysaccharrides, and nucliec acids are...
complex polymers
Monomer
a molecule that can be bonded to other identical molecules to form a polymer
Functional groups
small groups of atoms with specific chemical properties
Isomers
molecules that have the same chemical formula bout atoms are arranged differently
Structural isomer
atoms are bonded differently
Cis- trans isomers
orientation of functional groups on eitherside of C=C bond differs
optical isomer
mirror image of each
What are the main elements in Proteins?
C, H, O, N, S
Are proteins polymers or monomers?
ALL proteins are polymers
consisting of one or more polypeptides
Condensation (dehydration) reactions
builiding reactions, link, small molecules together to form larger molecules
involves the removal of 1 molecule of H2O in turn creating a covalent bond between them
Polypeptides
long chain of amino acids
How are the proteins linked together?
By covalent bonds formed by condensation reactions, also known as peptide bond or linkages
4 levels of protein structure
Primary, Secondary, Tertiary, and Quaternary Structures
Primary Structure
amino acid sequence (encoded by dna and established by covalent bonds)
Substitution of just one amino acid may alter protein function
determines the rest of the structures
Secondary Structure
regular, repeated spatial pattern (due to H-bonding b/ween R- groups of amino acids)
Alpha helix (coil) a
Beta pleated sheet B
Tertiary Structure
3D shape of protein composed of 1 polypeptide(results from interactions b/ween amino acid R-groups)
4 types of R-group interactions: Hydrogen Bond, Hydrophobic interactions, Disulfide bridge, ionic bond
4 types of R-group interactions
Hydrogen Bond- forms b/ween polar R-groups
Hydrophobic Interactions- forms b/ween nonpolar R-groups
Disulfide bridge- forms b/ween terminal sulfurs of crysteine R group
Ionic Bond- form b/ween charged R-groups
Quaternary structures
3-D shape of a protein composed of 2 or more polypeptide chains (results from interactions b/ween polypeptide chains)
ex: Insulin- 2 polypeptides
Collagen- 3 polypeptides
Hemoglobin- 4 polypeptides
Denaturation
decreased function resulting from a change in secondary, tertiary, or quaternary structure
(NOT primary structure tho:peptide bonds linking amino acids not broken)
Most common denaturation agents are
heat
strong acids and bases(ph)
Hydrolysis Reactions
breaking down the reaction, bonds of large molecules to form smaller molecules
Involves addition of water
for every covalent bond broken we have to add one molecule of water
Carbohydrates contain what elements?
composed of C, H, O
the # of Carbons = # of Oxygens
a suffix of most carbohydrates
typical suffix is -ose (glucose)
Monosaccharides
mono= one sacharides= sugar (one sugar)
possess 3-7 carbon atoms
General formula: (CH2O)_n
multiple OH(alcohol) and 1 carbonyl group (aldehyde and ketone)
serve as carbon skeletons, major source of energy
Disaccharides
2 sugars
2 monosaccharides linked by a covalent bond or glycosidic linkage
Examples of Disaccharides
Maltose (a-glucose + B-glucose)
Cellobiose (B-glucose+B-glucose)
Sucrose (a-glucose +fructose)
Lactose( B-glucose+ galactose)
Oligosaccharides
3-20 linked monosaccharides
often attached to cell membranes
Polysaccharides (polymers)
thousands of glucose units linked by glycosidic linkages (covalent bonds)
Examples of polysaccharides
cellulose- component of plant cell walls (#1 organic compound on Earth)
Starch- energy storage compound in plants
Glycogen- short-term energy storage compounds in animals
3 structures of polymers
Linear (celluose)
Branched (starch)
Highly Branched (glycogen)
Chemically modified Carbohydrates
sugar phosphates
amino sugars
Chitin- polymer of N-acetylglucosame
Elements in Lipids
C, H, and O
very little oxygen compared to carbons
Lipids
All are non polymers
all are hydrophobic (nonpolar covalent bonds)
Fats and oils (lipids)
longterm energy storage compounds in animals and plant seeds
consist of 1 glycerol and 3 fatty acid chains
Ester linkages
covalent bonds that link fatty acids to glycerol
types of lipids
Fatty Acids
Phospholipids
Canotenoids
Steroids
Fatsoluble vitamins
Waxes
Fatty acids
may be saturated or unsaturated
Saturated
means that all of the carbons are surrounded by hydrogens in the linkage
Unsaturated
when the carbons are not completly surrounded by hydrogens
happens when you double bond a carbon in the linkage
Phospholipids
components of cell membranes
consist of glycerol and 2 fatty acids and a phosphate containing compound
both hydrophobic and hydrophilic
Amphipathic
when an compound is both hydrophobic and hydrophilic
Canotenoids
light absorbing pigments in plants and animals
Ex: B- carotene (produces vitamin A)
Steroids
have multiple fused carbon rings
Ex: cholesterol, vitamin D, and some hormones (cortisol, testosterone, estrogen)
Fat soluble vitamins:
vitamin A,D,E,K (dont overdose on these)
Waxes
large molecules
composed of saturated fatty acids and a saturated alcohol
Nucleic Acids
DNA and RNA
polymers of nucleotides linked by phosphodiester linkages
what is a nucleic acid composed of?
C,H,O,N, and P
Nucleotides
composed of a base, a sugar, and a phosphate
RNA (ribonucleic acid)
involved in synthesis of proteins
TRNA, RRNA, and MRNA
usually single stranded
sugar is ribose
bases are A,G,C,U
DNA (deoxyribonucleic acid)
hereditary material
usually double stranded
sugar is a deoxyribose
bases are A,G,C,T
Reproduces itself exactly (replication)
can encode its information into RNA(transcription)
composed of genomes
Replication
DNA replicates(clones) itself exactly
involves the entire DNA molecule
Transciption
DNA encodes its information into RNA
involves sections of the DNA molecule
Spontaneous generation was disproved by...
Francesco Redi (1668) and Louis Pasteur( 1859)
Life began in water because
of the lack of radiation
Two theories of life on Earth
Life came from outside earth
and
Life originated on earth by chemical evolution (primordial soup theory)
Life came from outside earths support:
meteorite carried purines, pyrimidines, sugars, and 10 amino acids (1969)
support behind life orginated on earth by chemical evolution (primordial soup theory)
experiments of Miller and Urey (1950's)
Miller and Ureys experiment
used prebiotic "hot chemistry" simulation
and prebiotic "cold chemistry"simulation
Sunsequent experiments assing N gas, CO2, H2S, and SO2 to miller-urey atmosphere yeild
with this they found all basic components of life
What were the results in the Miller and Ureys experiment
all 5 DNA/RNA bases
All 20 amino acids
fatty acids
vitamin B6
Nicotenamide (component of NAD)
Carboxylic acid
What is the function of a catalyst?
speeds up a reaction
What are the major biological catalysts?
enzymes
Origin of Large molecules of life:
Monomers combine spontaneously in an aqueous solution to form macromolecules( too slowly to produce life) thus the presence of catalysts come into play
What is known to be 1st biological catalysts as well as 1st genetic material?
RNA
idea is known as RNA world
RNA World evidence
some present day RNA's(ribozymes) function as enzymes
present say retroviruses possess an enzyme (reverse transcription) that catalyzes synthesis of DNA from RNA
What are the oldest known fossils of cells?
found in western Australia (3.5bya)
origin of the first cells
formation of protocells
then enclosed RNA can replicate using nucleotides from outside protocells
Glycosidic linkage/bond
covalent bond formed between monosaccharides
Phosphodiester linkage/ bond
covalent bond formed between two nucleotides
Amino Acid
Organic compound containing both NH2 and COOH groups; monomers of proteins
Peptide bonds/linkage
covalent bond formed two amino acids
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