Studied by 19 people
what are the 5 themes of biology?
organization, information, energy + matter, interactions, evolution.
difference btw inductive and deductive reasoning?
inductive: specific observation →general conclusion
deductive: general observation →specific conclusion
out of 92 natural elements, how many are essential?
20-25%
what is the molecular fomula?
formula of compound showing the number of atoms of each element (ie. C4H10)
what is molecular stucture?
showing how atoms in molecules are bonded together
how are compounds different than molecules?
compounds have to have at least 2 dif elements
what are isomers?
organic molecules that have identical formulas but different arrangement of atoms
what are orbitals?
space where electrons are found; electron shells contain electrons at particular energy levels distributed among orbitals
how many electrons can each orbital occupy?
2
what is the atomic number?
number of protons; determines atoms identity
what is atomic mass?
average of mass number (protons + neutrons) for all isotopes
whats an isotope?
atoms of same element with different amounts of neutrons
what determines molecular shape?
the position of the molecules orbitals (ie. atoms with s and p orbitals make tetrahedrons)
rate of reaction is affected by ________ of __________.
concentration, reactants
what 4 properties make water special?
cohesion of water molecules, moderation if temperature by water, floating of ice on liquid water, water being te solvent of life.
describe cohesion of water molecules.
water molecules are linked by multiple hydrogen bonds making water more structured, this results in cohesion which is the cause of high surface tension and adhesion which can counter gravity.
describe moderation of temperature by water.
water moderates air temperature by absorbing heat from air that is warmer and releasing stored heat to air that is cooler.
what is specific heat and how does it help water?
specific heat is the amount of heat that must be absorbed or lost for 1g of substance to change 1 degree C. water’s ability to stabilize temperature is due to its relatively high specific heat.
why does heat cause such a small change to water?
heat must be absorbed to break hydrogen bonds and released when they form. so when heat is absorbed by water most of it is used to break hydrogen bonds before the molecules can move faster.
what is evaporative cooling?
the process in which the surface of an object becomes cooler during evaporation, contributes to the stability of lakes and ponds.
describe floating of ice on liquid water.
water is less dense as a solid than as a liquid because it expands when it solidifies, so ice is less dense than liquid water causing it to float
described how water is the solvent of life.
water is a versatile solvent due to its polarity
what is an acid?
an acid is a substance that increases the hydrogen ion (h+) concentration of a solution by donating hydrogen ions. numbers 1-7 on pH scale
what is a base?
a substance that reduces the hydrogen ion (h+) concentration of a solution by accepting hydrogen ions or dissociating to form hydroxide ions (OH-) which combine with hydrogen ions to form water. number 7-14 on pH scale
what is the pH of a solution?
the negative logarithm (base 10) of the hydrogen ion concentration: pH= -log[H+)
what is a buffer?
a substance that maintains changes in concentration of H+ and OH- in a solution.
what 4 ways can carbon skeletons vary?
length, branching, double bond position, presence of rings
whats a structural isomer?
isomers that differ in the covalent arrangement of atoms
whats a cis-trans ismomer?
isomers that differ in the spatial arragement of their atoms due to the inflexibilty of double bonds
describe a cis isomer and trans isomer
cis- 2 atom/atom groups on same side
trans- 2 atom/atom groups on oposite sides
what are enantiomers?
isomers that are mirror images of each other in shape due to presence of asymetric carbon, usually only 1 side is effective
what are the 7 most important functional groups?
hyrdoxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, and methyl groups
what is a dehydration reaction?
a reaction in which 2 monomers are covalently bonded to each other with the loss of water molecule to form a polymer.
what is hydrolysis?
the dissembling of polymer by the addition of a water molecule.
monosaccharides generally have a molecular fomula of what unit?
CH2O
what are some trademarks of sugars?
carbonyl group and multiple hydroxyl groups
what is the difference btw aldose and ketose sugars?
aldose- cabonyl group at end of the skeleton (glucose)
ketose- carbonyl group within skeleton (fructose)
what is a glycosydic linkage?
a covalent bond btw 2 monosaccharides by dehydration reaction
what are the 2 functions of polysaccharides?
storage and structure
what are 2 storage polysaccharides?
starch- a polymer of glucose stored by plants that can be withdrawn with hydrolysis to be used a energy
glycogen- a polymer of glucose used by animals as short term energy
what are 2 structural polysaccharides?
cellulose- used in the walls of cell plants, the unbrached structure helps to impart strength
chitin- used by anthropods to build exoskeletons and by fungi to replace cellulose
what is a fat?
a glycerol molecule joined to 3 fatty acids; they re hydrophobic and main function is energy storage
what are fatty acids?
long carbon skeletons with 16-18 hydrocarbons connected to a carboxyl group
what makes fats hydrophobic?
the nonpolar hydrogen-carbon bonds in the fatty acids
whats the difference btw unsaturated and saturated fats?
saturated fats- dont have double bonds so more saturated with hydrogen resulting in them being solid
unsaturated fats- contain 1 or more double bonds so less hydrgogen resulting in them being liquid
what is a phospholipid?
a glycerol connected to 2 fatty acids and a phosphate group; major part of membranes
in a phospholipid the hydrocarbon tails are __________ and the head is ___________.
hydrophobic, hydrophillic
what are steroids?
lipids characterized by a carbon skeleton consisting of four fused rings (ie. cholesterol)
what are amino acids?
an organic molecule with both an amino group and carboxyl group; protein monomer
how is a polypeptide formed?
when 2 amino acids are positioned with the carboxyl group one to the amino group of another, a dehydration reaction can join them to form a polypeptide
describe the levels of structure in polypeptides
primary structure- linear chain of amino acids
secondary structure- regions stabilized by hydrogen bonds btw atoms of the polypeptide backbone (coils and folds)
tertiary structure- 3-D shape stabilized by interactions btw side chains (overall shape)
quarternary structure- association of 2 or more polypeptides
what can injure/destroy proteins?
change in pH, change in salt concentration, change in temperature can cause denaturation
what do nucleic acids do?
store, transmit, and help express hereditary information
what make nucleotides?
a 5-carbon sugar, a nitrogenous base, and a phosphate group
in the sugar phosphate backbone one end has a phosphate to a _’ carbon and one end has a hydroxyl group to a _‘ carbon
5, 3
what is genomics?
the system study of whole sets of genes and interactions as well as comparisons btw species
what are bioinformatics?
the use of computer software that can handle large data sets
what is a light microscope?
a microscope in which visible light is passed through the specimen and the through glass lenses which refract the light to magnify it
what are the 3 principles of microscopy?
to enhance magnification, resolution, and contrast
what is an electron microscope?
a microscope that focuses a beam of electrons through specimen and onto surface
explain the 2 types of electron microscopes.
transmission electron microscope- used to study internal structure of cells; specimen is stained with heavy metal to enhance electron density
scanning electron microscope- used for detailed study of topography of specimen; electron beam excites electrons and electrons are scanned and displayed as 3-D
explain the structure of the nuclear envelope
a double membrane that is perforated by pore structures; a protein structure called pore complex regulates entry and exit; the nuclear envelope is lined with nuclear lamina, protein filaments which maintain shape
what are ribosomes?
cellular components that carry out protein synthesis; they are suspended in the cytosol (free) or attached to the ER or nuclear envelope (bound)
what organelles are part of the endomembrane system?
ER, Golgi apparatus, lysosomes, and vacuoles
what is the endoplasmic reticulum?
a bio synthetic factory that consists of a network of membranous tubules and sacks called cisternae
describe the rough and smooth ER
the smooth ER lacks ribosomes and does the synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poison, and storage of calcium ions
the rough Er contains ribosomes and makes secretory proteins and is a membrane factory (phospholipids)
explain the structure of the Golgi apparatus
the golgi consistes of membranous sacs called cisternae, the cis face of the cisternae is near the ER and receives products, the trans face is on the other side ships products to vesicles
what are lysosomes?
digestive compartments; membranes of hydrolytic enzymes that eukaryotic cells use to digest (hydrolyze) macromolecules
what is phagocytosis?
when a lysosome containing active hydrolytic enzymes fuses with a food vacuole and the enzymes digest the food particles, which become nutrients for the cell
what is authophagy?
when a vesicle with a damaged organelle fuses with a lysosome; the organelle is digested and its components recycled
what are some types of vacuoles?
contractile vacuole- used by unicellular protists to pump water
central vacuole- absorbs water and enlarges in plants to minimize growth of cytoplasm
explain the endosymbiont theory
it states that an early ancestor of eukaryotic cells (host cell) engulfed and oxygen using non-photosynthetic prokaryotic cell. the engulfed cell formed a relationship with the host cell and they eventually merged to a eukaryotic cell with a mitochondrion
what supports the endosymbiont theory?
there are 2 membranes surrounding mitochondrion and choloplast
ribosomes and DNA in inner membranes
they are autonomous
explain the structure of mitochondria
enclosed by 2 lipid bilayers embedded with proteins
the mitochondiral matrix (enclosed by inner membrane) contians enzymes, DNA, and ribosomes
the cristae (fold in inner membrane) gives large surface area to enhance productivity
what is the structure of chloroplasts?
intermembrane; thylakoids inside make stacks called granum; outside of thylakois is the stroma which contains DNA, ribosomes, and enzymes
what are peroxisomes?
they are specialized metabolic compartments bounded by membrane; they contain enzymes that remove hyrdogne and transfer it to oxygen creating H202 (hydrogen peroxide) to be used for cellular respiration
what is the role of the cytoskeleton?
to give mechanical support to the cell and maintain its shape
what is the purpose of microtubules?
to shape and support cells and re tracks for motor proteins; they also guide vesicales in cell distribution
what is the structure of microtubules?
hollow rods contructed from globular proteins called tubulins
what are tubulim dimers?
consist of 2 polypeptides called a tubulim and b tubulim, they grow by adding more tubulim dimmer and have a plus end that adds or releases tubulims at a higher rate
many protists are propelled through water by ______ or ___________
cillia, flagella
what are microfilaments (action filaments)
thin solid rods made from actin (a globular protein) that bear tension and support cell shape to make cell gel like; they also make the protein myosin for muscle cell contraction
what are intermediate filaments?
found in vertebrates as a permanent cell shape holder (they bear tension); they are very sturdy and surround nucleus
what is the structure of the plant cell wall?
made from microfibrils made of cellulose with a mix of proteins and strong pores
what is the extracellular matrix?
a part of animal cells that regulates cell behavior made up of glycoproteins and carb containing molecules (collagen and fibroconectin)
what is plasmodeta?
specialized junctions that connect plant cell walls
what are 3 types of animal cell junction?
tight junctions- tightly pressed, bounded by proteins
desmones- long sheets, muscle cells
gap junctions- communications, tissue, embryo
explain the fluidity of membranes
membranes are held together by weak interactions and materials can shift making fluid
what are integral proteins?
penetrate the hydrophobic interior of lipid bilayer
what are peripheral proteins?
not embedded in lipid bilayer
explain some functions of proteins
transport- channel of shuttle
enzymatic activity- enzyme where reactants bind
signal transduction- signaling molecule can relay message to cell
cell cell recognition- ID tags
intercellular joining- hook together
attachment to cytoskeleton of ECM- maintain cell shape
what is selective permeability?
some substances cross easier than other
nonpolar molecules are _________ so they can dissolve across bilayer
hydrophobic
the ______ interior of membranes prevents passage of _______ molecules
hydrophobic, polar
how can hydrophilic (polar) subanstaces pass through lipid bilayer?
by avoiding contact with lipid bilayer by using transport proteins
how do channel proteins function?
by having a hydrophillic passageway
how do carrier proteins function?
by holding passages and changing shapes to shuttle across membrane
what is diffusion?
the movement of particles of any substance so that they spread out into the available space
in the absence of other forces, a substance will diffuse from ___ concentrated to ___ concentrated; _____ its concentration gradient
more, less, down
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