Exam #1 Flashcards
carbon in biology
the framework of biological molecules consists primarily of carbon bonded to:
* another carbon
* O, N, S, P, and H
can form 4 covalent bonds
hydrocarbons
- molecule consisting only of carbon and hydrogen
- HYDROCARBONS ARE NONPOLAR
Isomers and the 2 types
- molecules with the same molecular/empirical formula (which means that they have the same # of atoms)
1. structural isomers
2. stereoisomers: differ in how groups are attached
enantiomers
mirror image molecules = chiral
example: D-sugars
define polymer
built by linking monomers
define monomer
small, similar chemical subunits
monomer for carbohydrates
monosaccharide
monomer for nucleic acid
nucleotide
monomer for protein
amino acid
dehydration synthesis
- formation of large molecules by the removal of water
- monomers are joined to form polymers
hydrolysis
- breakdown of large molecules by the addition of water
- polymers are broken down to monomers
carbohydrates
- molecules with a 1:2:1 ratio of C, H, O
- CH2O
- C-H hold much energy
- Carbs are good energy storage
- example: sugars, starch
Monosaccharides
- simplest carbohydrate
- 6 carbon sugars are important
glucose
C6H12O6
* fructose is a structural isomer of glucose
* galactose is a stereoisomer of glucose
Disaccharides
- 2 monosaccharides linked together by dehydration synthesis
- used for sugar transport or energy storage
- sucrose, lactose, maltose
polysaccharides
- long chains of monosaccharides (linked thru dehydration synthesis)
- energy storage (plants use starch)
- structural support (plants use cellulose)
nucleic acids
name polymer and monomer
polymer: nucleic acids
monomers: nucleotides
* nucleotides are connected by phosphodiester bonds
nitrogenous bases include:
purines: adenine and guanine
pyrimidines: thymine, cytosine and uracil
deoxyribonucleic acid (DNA)
- encodes information for amino acid sequence of proteins
- base-pairing rules:
A with T (or U in RNA)
C with G
define double helix
2 polynucleotide strands connected by hydrogen bonds
ATP
adenosine triphosphate
- primary energy currency of the cell
ribonucleic acid (RNA)
- single polynucleotide strand
- RNA uses info in DNA to specify sequence of amino acids in proteins
DNA vs RNA
DNA
* contains deoxyribose
* contains thymine
* double stranded sugar phosphate
RNA
* contains ribose
* contains uracil
* sigle stranded sugar phosphate
NAD+ and FAD+
- nicotinamide adenine dinucleotide
- flavin adenine dinucleotide
- electron carriers for many cellular rxns
the 7 protein functions:
- enzyme catalysis
- defense
- transport
- support
- motion
- regulation
- storage
protein
- proteins are polymers
- composed of 1 or more long, unbranched chains
- amino acids are monomers
- amino acids are joined by dehydration synthesis
- peptide bond
1st and 2nd levels of protein structure
shape of protein = its function
1. primary: sequence of AA
2. secondary: interaction of groups in the peptide backbone
* alpha helix
* beta helix
3rd and 4th levels of protein structure
- tertiary: final folded shape of a globular protein
- stabilized by a number of forces
- final level of structure IF protein only consists of a single polypeptide chain - quaternary: arrangement of individual chains (subunits) in a protein with 2 or more polypeptide chains
motifs
additional structural characteristics
- common elements of secondary structure seen in many polypeptides
- useful in determining the function of unknown proteins
domains
additional structural characteristics
- functional units within a larger structure
- most proteins made of multiple domains that perform different parts of the protein’s function
chaperone proteins
- chaperone proteins help protein fold correctly
- deficiencies in chaperone proteins implicated in certain diseases
- cystic fibrosis (protein fails to fold)
define matter
- matter has mass and occupies space
- all matter is composed of atoms
atomic structure
atoms are composed of:
Protons: (+) located in the nucleus
Neutrons: neutral charge, located in the nucleus
Electrons: (-) located in orbitals surrounding the nucleus
atomic number
atomic number = number of protons
number of protons = number of electrons
define element
any substance that cannot be broken down to any other substance by ordinary chemcial means
mass vs weight
mass: refers to the amount of substance
weight: refers to force gravity exerts on substance
atomic mass
atomic mass = sum of protons and neutrons
* each proton and neutron has a mass of 1 dalton
ions
charged particles, means that they are unbalanced
N3-
cation
(+ charge), more protons than electrons
anion
(- charge), more electrons than protons
isotopes
- atoms of a single element that possess different numbers of neutrons
- radioactive isotopes are unstable and emit radiaion as the nucleus breaks up
- Half-life: time it takes for one-half of the atoms in a sample to decay
electron arrangement
- chemical behavior is due to the number and arrangemnet of its electrons
- Bohr: electrons in discrete orbitals
no orbital can contain more than 2 electrons
electron energy trends
electrons farther from the nucleus have more energy
redox
in some rxns, electrons can be transferred from one atom to another
oxidation
loss of an electron
reduction
gain of an electron
OIL RIG
valence electrons
number of electrons in outermost energy level
define inert
(nonreactive) elements have all eight electrons
define molecules
groups of atoms held together in a stable association
define compounds
are molecules containing more than one type of element
ionic bonding
- formed by the attraction of oppositely charged ions
- gain or loss of electrons forms ions Na+
- electrical attraction of water molecules can disrupt the forces that hold ions together
covalent bonding
when atoms share 2 or more valence electrons
electronegativity
- atoms affinity for electrons
- most electronegative element is F
- nonpolar covalent bonds = equal sharing of electrons
- polar covalent bonds = unequal sharing of electrons
the more electronegative atom wants the electrons more
chemical rxn
involve the formation or breaking of chemical bonds
reactants = orginal molecules
products = molecules resulitng from rxn
3 things that influence chemical rxns
- temperature
- concentration of reactants and products
- catalysts
polarity of water
- within the water molecule, the bonds between oxygen and hydrogen are highly polar
- O is much more electronegative than H
- partial electrical charges develop
- Oxygen is partially negative δ-
- Hydrogen is partially positive δ+
cohesion
polarity of water allows water molecules to be atteached to one another
(water molecules stick to each other due to hydrogen bonds)
adhesion
water molecules stick to other polar molecules by hydrogen bonding
6 properties of water
- water has a high specifc heat
- water has a high heat of vaporization
- solid water is less dense than liquid water
- water is a good solvent
- water organizes nonpolar molecules
- water can form ions
pH
pH is the negative logarithm of hydrogen ion concentration of solution
define acid
- any substance that dissociates in water to increase the [H+] and lower pH
- the stronger the acid the more hydrogen ions it produces
define base
- any substance that combines with H+ dissolved in water, and thus lowers the [H+]
Buffers
- a substance that resists changes in pH
- they release hydrogen ions when a base is added
- absorbing hydrogen ions when acid is added
7 characteristics of all living organisms
- Composed of cells
- Complex and ordered
- Respond to their environment
- Can grow, develop, and reproduce
- Obtain and use energy
- Maintain internal balance
- Allow for evolutionary adaptation
hypothesis
tentative educated guess
theory
description of the world that covers a relatively large number of phenomena and has met many observations and experimental test
“law of nature”
an overarching statement of how the universe works
scientific method
- Make an observation/identify a pattern
- Create a hypothesis
- Device an experiment to test the prediction of the hypothesis
- Test the prediction by running the experiment
- Evaluate the results of the experiment against your hypothesis
6.Repeat
deductive and inductive reasoning
- Deductive reasoning uses general principles to make specific predictions
- Inductive reasoning uses specific observations to develop general conclusions
define reductionism (philosophical approach)
to break a complex process down into its simpler parts
define systems biology (philosophical approach)
focus on emergent properties that can’t be understood by looking at simpler parts
cell theory
- All organisms composed of cells
- Cells are basic units of life
- All cells come from preexisting cells
define gene
discrete unit of information
genome
entire set of DNA instructions
bacteria
single-celled prokaryote
archaea
single-celled prokaryote
eukarya
single-celled or multicelled eukaryote
evolutionary conservation
all organisms today descended from a simple creature 3.5 billion years aog
nonequilibrium state
- living systems are open systems
- constant supply of energy needed
Darwin and Evolution Book
on the origin of species by means of natural selection
