Tommy Wiaduck 2014
Tommy Wiaduck Honors Biology Midterm Exam Review 2014 This study guide is an extensive collaboration of class powerpoints and independent notes. It provides a large amount of direct information. Application and use of the information ultimately depends on each individual student. It is recommended to use other resources in addition to this review. This study guide does not guarantee any scores or accuracy. If you have questions or need help in Biology, please contact Tommy Wiaduck. Topic 1: Exploring Life
The living world is a hierarchy, with each level of biological structure building on the level below.
With the additional of each new level, we get new emergent properties Atom > Molecule > Organelle > Cell > Tissue > Organ > Organ System >
Organism > Population > Community > Biosphere Biosphere:
all environments on Earth that support life Ecosystem:
all the organisms living in a particular area Community:
the array of organisms living in a particular ecosystem Population:
all the individuals of a species within a specific area Organism:
an individual life form Organ System:
composed of organs (have specific functions) Organs:
provide specific functions for the organism Tissues:
made of groups of similar cells Cells:
living entities distinguished from their environment by a membrane Organelle:
membranebound structures with specific functions Molecules:
clusters of atoms Living Organisms Interact with their Environments (exchanging matter and energy)
interactions between living and nonliving components is required producers:
photosynthetic organisms that provide their own food consumers:
animals/organisms that profit/eat from plants chemical nutrients:
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nonliving components required for life to be successful, an ecosystem must:
recycle chemicals necessary for life move energy through the ecosystem
energy cannot be recycled (energy enters as light ; leaves as heat)
Cells are an organism's basic units of structure and function: form generally fits function
if you change the structure, you change the function prokaryotic cells
simple and small (no membranebound organelles) bacteria
eukaryotic cells possess organelles seperated by membranes
plants, animals, and fungi All forms of life have common features
Order the complex organization of living things
Regulation/Homeostasis: ability to maintain an internal environment consisten with life
Growth and Development: consistent and specific pattern for growth/development controlled by DNA
Energy Utilization/Processing: organisms taking in energy and transforming it to do work (useful form)
Response to Environment: respond to stimuli from their environment (reaction)
Reproduction: organisms reproduce (life comes from life biogenesis)
Evolutionary Adaptation: life evolving in response to interactions between organisms and their
environment (acquisition of traits that best suit organism in environment) Three Domains for Diversity of Life
bacteria: prokaryotic ; unicellular (often microscopic)
archaea: prokaryotic, often unicellular and microscopic
eukarya: eukaryotic and contain nucleus and organelles
fungi, animalia, plantae, protists Evolution Explains Unity and Diversity of Life:
Charles Darwin evolution:
biology's core theme and explains unity and diversity of life
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natural selection: individuals in a population inherit characterists that will help them
survive in an environment (only fit organisms are reproduced, slowly weeding out certain traits that prevent survival)
increases frequency of certain inherited variants/traits ex) food is high up... only taller animals can eat, shorter
animals die... species now are mainly tall The Process of Science
there are two main approaches to understand natural causes for phenomena discovery science:
provable observations and measurements to describe science hypothesisbased science:
uses data from discovery science to explain you must propose and test hypotheses
ex) Why doesn't the flashlight word? 1) Bulb or 2) Batteries
control group: all variables are held constant
experimental group: one factor or treatment is varied
theory vs. hypothesis theory:
supported by a large (and usually growing) body of evidence
hypothesis: proposed explanation for a set of osbservations
Biology and Everyday Life science and technology are interdependent
science wants to understand natural phenomena technology applies science for a specific purpose
Topic Review: 1) Describe life's hierarchy of organization
A: Atom > Molecule > Organelle > Cell > Tissue > Organ > Organ System > Organism > Population > Community > Biosphere
2) Describe living organisms' interactions with their environments
A: light from the sun goes to producers, which use it to make food (release heat energy), which is then eaten by consumers (release heat energy), and chemical nutrients cycle through the ecosystem.
3) Describe the structural and functional aspects of cells
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A: Prokaryotic Cells archaebacteria and bacteria small size ; DNA is not seperated from rest of cell no membranebound nucleus or other organelles tough external walls
Eukaryotic Cells protists, plants, fungi, animals DNA is seperated from rest of the cell (organized in chromosomes) cytoplasm surrounds nucleus and contains various organelles some have a cell wall outside plasma membrane (plant cells)
4) Explain how the theory of evolution accounts for the unity and diversity of life
A: All living species descend from ancestral species (differences reflect evolutionary change) ; natural selection
5) Distinguish between discovery science and hypothesisbased science
A: Discovery Science: use verifiable/provable observations and measurements to describe science and
phenomenas HypothesisBased Science:
use data from discovery science to explain science (you must propose and test) 6) Describe ways in which biology, technology, and societs are connected
A: technology improves our standard of living, but also brings about problems like population growth, acid rain, deforestation, global warning, endangered species, nuclear accidents, toxic waste, etc...
A: technology extends our ability to observe and measure science (improvement) Topic 2: The Chemical Basis of Life
Chemical Elements & Compounds Life requires about 25 chemical elements
element: substance that cannot be broken down there are 92 elements, only few are in a pure state
Trace elements: elements required by organisms (only in small quantities)
although you only need little of them, they are vital ex) B, Cr, Co, Cu, F, I, Fe, Mn, Mo, Se, Si, Sn, V, Zn
lack of trace elements bring about disease lack of iron: canno transport oxygen lack of iodine: holy goiter
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some are added to food/water for various reasons preserve it, more nutrious, look better
Biologically Important Elements Carbon, Oxygen, Hydrogen, and Nitrogen
C, O, H, N > make up about 96.3% of body weight/living matter Compounds
compounds are substances cosisting of two or more different elements combined in a fixed ratio
Table Salt (NaCl sodium chloride) many compounds in living organisms (including DNA) include, C, H, O,
and N Atoms and Molecules
Atoms smallest possible unit of matter that retains physical and chemical
properties of its element Subatomic Particles (3 Important): proton (+), neutron (+/)
electron () neutrons and protons are packed in an atom's nucleus
atomic number: number of protons in an atom neutral atoms have the same amount of protons and electrons
mass number: number of protons and neutrons in an atom add protons and neutrons for mass number subtract atomic number from mass number to find amount of neutrons
Isotopes: isotopes have the same number of protons and electrons, but different
numbers of neutrons ex) carbon containing 8 neutrons instead of 6 is 14C
radioactive isotops are unstable emit subatomic particles and/or energy as radioactivity they can help or hurt us
your body cannot detect isomers, but certain machines like the PET can
Electrons electron shells (orbitals) are energy levels where electrons are
atoms can have one, two, or three, electron shells number of atoms in the outermost shell determines
chemical properties of an atom 1st Shell: 2 e Max ; 2nd Shell: 8 e Max
chemical bonds attractions between atoms by sharing, donating, or receiving e's
(to fill their outer electron shells) Structural Formula: HH
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Molecular Formula: H2 Molecules: two or more atoms held together by chemical
bonds Covalent Bonds:
formed by sharing a pair of valence electrons (outer shell electrons)
Single Covalent Bond: sharing single pair of valence electrons
Double Covalent Bond: atoms shair two pairs of valence electrons (ex: O=O)
Triple Covalent Bonds: share 3 pairs of valence e's electronegativity: attraction/pull for shared electrons
Nonpolar & Polar Covalent Bonds: Nonpolar Covalent Bond:
formed by equal sharing of electrons between atoms (usually of molecules made by same element ex: O2, H2)
Polar Covalent Bond: formed by unequal sharing of electrons between
atoms atoms involved have different
electronegativities forms a polar molecule
Ionic Bonds: bond formed by the attraction after the complete transfer of
an electron from a donor to an acceptor ion: charged atom or molecule
Hydrogen Bonds: bond formed by the charge attraction when a hydrogen
atom covalently bonded to an electronegative atom is attracted to another electronegative atom
positive end attracts to neighboring oppositvely charged regions
positive charged region is always a hydrogen
Water's Life Supporting Properties cohesion
molecules sticking together (formed by hydrogen bonds) surface tension
measure of how difficult it is to break the surface of a liquid adhesion
molecules sticking to other things ex) water sticking to the wall in tree to move up tree
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heat water can resist temperature change greater than other liquids
heat is the energy associated with movement of atoms and molecules in matter
temperature measures the intensity of heat ice is less dense than liquid water
ice: hydrogen bonds are stable ice floats, oceans and lakes dont freeze over
liquid: hydrogen bonds constantly break and reform water is the universal solvent
solution: liquid consisting of a uniform mixture of two or more substances
solvent: dissolving agent solute: substance that is dissolved
pH Acids and Bases water molecules can break apart into ions (both are reactice)
hydrogen ions (H+) hydroxide ions (OH)
acids higher concentration of H+ than OH (removes OH)
bases higher concentration of OH (reduces H+ concentration)
neutral solution equal concentration of H+ and OH
pH Scale (pH = potential of hydrogen) describes whether a solution is acidic or basic
0 = most acidic (battery acid) 14 = most basic (bleach) 7 = neutral ; neither acidic nor basic (pure water)
acid precipitation rain, snow, or fog with a pH lower than 5.6
returning burned fossil fuels released into air as CO2 buffers
substances that minimize large and sudden changes in pH accepts H+ when too acidic donates H+ when too basic
Chemical Reactions chemical reaction
formation of water from hydrogen and oxygen making a molecule from two atoms rearranging matter
reactants used to make the product (ex: H2 and O2)
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product made from reactants in a chemical reaction (ex: H2O)
Topic 3: The Molecules of Cells
Introduction to Organic Compounds organic compounds
any carbonbased molecules ex) Methane (CH4)
four covalent bonds like 4 hydrogens to carbon molecular diversity is based on properties of carbon
composed of carbon bonded to other elements hydrocarbons
compounds composed only of carbon and hydrogen carbon skeleton
chain of carbon atoms (branched or ubranches) isomers
different compounds with the same molecular formula different structure/arrangement
if you change the structure, you change the function Functional Groups
testosterone and estrogen are similar, other than their difference in functional groups
groups of atoms attached to an organic compound Hydroxyl Group (hydrogen bonded to an oxygen)
OH Carbonyl Group (carbon doublebonded to an oxygen atom)
C=O Carboxyl Group (carbon doublebonded to oxygen and hydroxyl group)
COOH Amino Group (nitrogen bonded to two hydrogen atoms)
NH2 Phosphate Group (phosphorus bonded to for oxygen)
OPO3^2 Biological Molecules
Carbohydrates, Lipids, Proteins, Nucleic Acids often called macromolecules because of large size also called polymers
made from many identical or similar subunits connected polymer building blocks: monomers
dehydration reactions
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links monomers together to form polymers results in polymer and water molecule (dehydrates two
monomers) hydrolysis
addition of water to break apart polymers adds back in water (hydro: water ; lysis: break)
enzymes speed up chemical reactions in the cell
Carbohydrates fuel and building material
carbohydrates: organic molecules made of sugars and their polymers monosaccharides
simple sugars ; simplest version of carbohydrate glucose and fructose
hook together to form polysaccharides main fuels for cellular work
used as raw materials to manufacture other organelles disaccharide
two monosaccharides bonded together thru dehydration reaction ex) glucose + fructose = sucrose
Polysaccharides polymers of monosaccharides
storage molecule or structural support cannot be used for energy in this large state
must be broken down by hydrolysis hydrophilic (waterloving)
very water absorbment (cotton fibers) starch
glucose polymer used as a storage polysaccharide in plants glycogen
glucose polymer used as a storage polysaccharide in animals hydrolyzed when glucose is needed
cellulose polymer of glucose that forms plant cell walls
structural ; cannot be digested by humans chitin
polysaccharide (that is a polymer of an amino sugar) used by insects and crustaceans to build exoskeletons
Lipids Diverse Hydrophobic Molecules
lipids: diverse grop of organic compounds that are insoluble in water, but will dissolve in nonpolar solvent
contain twice as much energy as a polysaccharide
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water fearing oil on ducks feathers repels water
Fats store large amount of energy lipids made from glycerol and fatty acids
one glycerol and three fatty acids triglycerides
fats composed of three fatty acids bonded to one glycerol Unsaturated Fats
fatty acids containing double bonds room for more hydrogen atoms (kinks/bends in carbon chain) liquid at room temperature
commercial products are artificially hydrogenated to prevent seperation Saturated Fats
maximum number of hydrogens (no double bonds) solid at room temperature
Phospholipids compounds with molecular building blocks of glycerol, two fatty acids, a
phosphate group, and usually an additional small chemical group attached to the phosphate
structurally similar to fats and are important in all cells cell membranes
cluster into a bilayer of phospholipids hydrophylic heads
in contact with the water of the environment hydrophobic tails
band in the center of the bilayer, away from water naturally arrange that way (sort of like a magnet)
Steroids lipids composed of fused ring structures with various functional groups attached cholesterol
plays a significant role in the structure of the cell membrane also synthesizes sex hormones
anabolic steroids synthetic variants of testosterone
causes buildup of muscle and bone mass can help treat disease, but also can be abused with
consequences like liver damage (leads to cancer) Proteins
Molecular Tools of the Cell protein: polymer built from various combinations of 20 amino acid monomers
contains one or more polypeptide chains polypeptide chains: polymers of amino acids arranged in a specific linear
sequence
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linked by peptide bonds enzymes
proteins that serve as metabolic catalysts speed up reactions, regular chemical reactions
Functionals of Proteins Structural Proteins
provide associations between body parts Contractile Proteins
(found within the muscle) ; movement Defensive Proteins
include antibodies of the immune system Signal Proteins
chemical messengers ; exemplified by hormones Receptor Proteins
server as antenna for outside Transport Proteins
carry oxygen ; ex: hemoglobin Proteins are made from amino acids linked by peptide bonds
amino acids: building blocks of proteins contain amino and carboxyl group (covalently bonded to a central carbon)
Hydrogen atom and the Rgroup (variable) are also bonded to central carbon
amino acids are hydrophobic or hydrophilic nonpolar: hydrophobic
less soluble in water polar: hydrophilic
solube in water peptide bond
covalently bonding the carboxyl group of one amino acid to the amino group of another
accomplished by an enzymemediated dehydration reaction create a water molecule in the process
Protein's Function depends on its specific shape amino acid sequence causes the polypeptide to assume a particular shape
this shape determines its specific function denatured proteins can no longer function
denaturation causes polypeptide chains to unravel and lose their shape (and their
function) caused by: shape change, temperature change, pH change, salt
concentration change Four Levels of Protein Structure
Primary Structure
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unique to amino acid sequence ; determined by genetic information linear shape
Secondary Structure results from coiling or folding of the polypeptide
caused by hydrogen bonding between certain parts of the polypeptide chain
creates an alpha helix shape may lead to a pleated sheet structure
Tertiary Structure overall, threedimensional shape
interactions between the R group of the amino acids Quaternary Structure
arrangement of multiple folded protein or coiling protein molecules in a multisubunit complex
Nucleic Acids Store and Transmit Hereditary Information
composed of monomers called nucleotides nucleotides have three main parts
5Carbon Sugar (Pentose) (RNA: ribose ; DNA: deoxyribose)
a phosphate group a nitrogenous base
DNA nitrogenous bases: Adenine (A), thymine (T), cytosine (C), and guanine (G)
RNA nitrogenous bases: A, C, G, and uracil (U)
uracil replace thymine in RNA both nitrogenous bases make up sugarphosphate backbones
repeating and protruding nitrogenous bases double helix
two polynucleotide strands wrap around each other to form the shape of DNA
A pairs with T ; C pairs with G (base pairs) RNA is usually a single polynucleotide strand
gene particular nucleotide sequence that can instruct the formation of a
polypeptide DNA molecules consist of many base pairs (and therefore,
many genes) determine the structure of protein, and thus, life's
structures and functions Deoxyribonucleid Acid (DNA)
contains coded information that programs all cell activity
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contains directions for its own replication is copied and passed from one generation of cells to the next found primarily in the nucleus makes up genes
contain instructions for proteins synthesis Ribonucleic Acid (RNA)
actual synthesis of proteins (coded for by DNA) on ribosomes in the cytoplasm messenger RNA carries encoded genetic messages
from nucleus to cytoplasm Mutations
alterations in bases or the sequence of bases in DNA lactose intolerance is a result of these mutations the gene that dictates lactose utilization is turned off in adulthood
mutations, over time, prevent the gene from turning off Topic 4: A Tour of the Cell
Cells on the Move Cells were first observed by Robert Hooke in 1665
most cells cannot be seen without a microscope Antoni van Leeuwenhoek described moving cells
not all cells move, however, the cellular parts are actively moving Light Microscope (LM)
light passes thru specimen, then thru glass lenses into viewer's eye you can magnify up to 1,000x
resolution: the ability to distinguish between small structures light microscopes cannot provide details of a small cell's structure
Electron Microscope (EM) can magnify specimens as small as 2 nanometers up to 100,000x uses a beam of electrons (as opposed to light)
Surface Area smaller the cell, larger the surface area (relative to volume)
Prokaryotic vs. Eukaryotic prokaryotic cells are structurally simpler
bacteria and archaea both have plasma membrane and 1+ chromosomes/ribosomes eukaryotic cells have membranebound nucleus (and other organelles)
prokaryotes have a nucleoid and no true organelles Eukaryotic Cells
partitioned into functional compartments
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four life processes in eukaryotic cells (depend upon structures and organelles)
Manufacturing nucleus, ribosomes, ER, and golgi
Breakdown of Molecules lysosomes, vacuoles, peroxisomes
Energy Processing mitochondria (animals) ; chloroplast (plants)
Structural Support, Movement, and Communication cytoskeleton, plasma membrane, cell wall
Animals vs. Plants Cells Lysosomes and Centrioles are not found in plant cells Plant cells have a rigid cell wall, chloroplasts, and central vacuole
(animals cells do not) Membranes
Selective Permeability plasma membrane
controls movement of molecules in and out of the cell membranes made of lipids, proteins, and carbohydrates
(phospholipids) Phospholipids form a 2layer sheet (bilayer)
hydrophilic heads face outward water loving
hydrophobic tails point inward water hating
proteins are attached to the surface Manufacturing
Endomembrane System nucleus: cell's control center (responsible for inheritence)
contains chromatin complex of proteins and DNA (makes chromosomes) DNA is copied within nucleus during interphase, before division
nuclear envelope: double membranes w/ pores allowing material to flow in and out of the nucleus
attached to a network of cellular membranes called the ER ribosomes: involved in the cell's protein synthesis ; make proteins
made in the nucleolus (inside nucleus) free ribosomes: suspended in cytoplasm bound ribosomes: attached to ER
endomembrane system: nuclear envelope, ER, golgi, lysosomes, vacuoles, and the plasma membrane
membranes in a eukaryotic cell are physically connected to compose this
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vesicles: embraneenclosed sacs that are pinched off portions of membranes, moving from the site of one membrane to another
communication results in synthesis, storage, and export of molecules
Endoplasmic Reticulum: a biosynthetic factory Smooth ER
no attached ribosomes synthesizes lipids, phospholipids, steroids, oils detoxifies drugs and poisons (usually in liver)
Rough ER attached ribosomes ; lines outer surface of membranes
synthesizes proteins (into gylcoprotein, usually) ships off to golgi in transportvesicle
Golgi Apparatus finishes, sorts, and ships
the receiving side of the golgi takes in products they are then modified as they move from one side of the golgi to
the other ships off packaged products in vesicles to other sites
Breakdown
Lysosomes digestive compartments within a cell (membranous sac containing
digestive enzymes) lack of specific lysosomes can lead to disease
remove or recycle damaged cell parts damaged part is inclosed in membrane vesicle lysosome fuses with vesicle (dismantles contests... breaks down
damaged organelle) cell destruction
"suicide sac" ; can destroy a cell if necessary Vacuoles
membraneenclosed sac that is larger than a vesicle Food Vacuole: formed by phagocytosis Contractile: pumps excess water from the cell Central Vacuole: large vacuole found in most plant cells
hydrolytic functions Summary of Endomembrane System
Rough ER > Vesicles > Golgi > Vesicles > Lysosomes/Vacuoles/Plasma Membrane
diagrams from power point may help understanding Energy Processing
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Energy Converting Organelles Mitochondria and Chloroplasts are the main energy transformers of cells
Mitochondria organelles which are the sites of cell respiration (found in nearly all
eukaryotic cells) Intermembrane Space:
narrow region between inner and outer membranes Mitochondrial Matrix:
enclosed by inner membrane contains enzymes used for cell respiration
Cristae: folds inside the mitochondria
Chloroplast convert solary energy to chemical energy (photosynthesis) Intermembrane Space:
seperates the double membrane Thylakoid Space:
space inside the thylakoids thylakoids: membranous sacs inside chloroplast grana: stack of thylakoids
Stroma: viscous fluid outside thylakoids
do not confuse with stomata Evolution Connection
Mitochondria and Chloroplasts evolved by endosymbiosis they both have 1) DNA and 2) ribosomes derived from prokaryotes
endosymbiosis mitochondria and chloroplasts were formerly small
prokaryotes that began living within larger cells Support, Movement, and Communication Between Cells
The Cytoskeleton provides structural suport to cells for motility and regulation
Cytoskeleton network of fibers thrughout cytoplasm that forms a dynamic framework for
support, movement, and regulation maintains cell shape (or changes it) motor proteins: organelle movement, muscle contraction
microtubules found inside cytoplasm of eukaryotic cells made of tubulin ; are hollow fibers shape the cell and act as motor protein tracks
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Centrosomes and Centrioles centirole: pair of cylindrical structures located in the centrosome of
an animal cell (nine sets of triplet microtubules arranged in ring) Cilia and Flagella
locomotor organelles found in eukaryotes that are formed from specialized arranged of microtubules
move by bending motor proteins called dynein arms Cilia: lots of tiny hairs working like the oars of a crew boat Flagella: undulates in a whiplike motion (sperm) basal body: cellular structure that anchors the microtubular
assembly of cilia and flagella microfilaments
support the cell's shape and are involved in motility provide cellular support participate in muscle contraction
Intermediate filaments reinforce cell shape and anchor organelles
Cell Surfaces and Junctions Extracellular Matrix of Animal Cells
functions in support, adhesion, movement, and development composed of strong fibers of collagen, which holds cells together and
protects the plasma membrane attaches through integrins
proteins that bind to membrane Tight Junctions
hold cells together tightly enough to block transport of substances thru intercellular space
prevent leakage of extracellular fluid Gap Junctions
specialized for transport between cytoplasm of adjacent cells channels allowing molecules to flow between cells
Anchoring Junctions fasten cells together into strong sheets, but permit substances to pass
freely Cell Walls
rigid cell walls are found in plant, buut not animal cells composed primarily of cellulose protects and provides skeletal support that keeps the plant upright against
gravity also prevents excess water uptake
plasmodesmata (plant cells have these instead of junctions) channels that perforate plant cell walls
small passage in cell wall
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connect cytoplasm of neighboring cells Topic 5: The Working Cell
Membrane Structure and Function Membranes are a fluid mosaic
composed of phospholipids and proteins surface looks mosaic because the proteins embedded in the
phospholipids appears fluid because the proteins can drift about in the
phospholipids many are made from unsaturated fatty acids (kinks in tails)
this prevents tight packing this keeps them liquid
aided by cholesterol wedged into the bilayer membranes contain integrins
integrins give the membrane stronger framework they attach to the extracellular matrix on the outside of the
cell, as well as span the membrane to attach to the cytoskeleton
glycoproteins identification tags
recognized by membrane proteins of other cells recognition
enables cells of the immune system to reject foreign cells, like infectious bacteria
membrane proteins function as enzymes signal transduction
messenger molecule > enzyme > activated molecule transport
passive: no energy required ; moves down concentration gradient
active: requires energy ; moves against concetration gradient
selective permeability some substances can cross or be transported easier than others
nonpolar molecules (CO2 and Oxygen) cross easily polar molecules (glucose, sugars) do not cross easily
Passive Transport diffusion
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process in whichparticles spread out evenly in an available space move from an area of more concentrated particles to a less
concentrated area diffuse down the concentration gradient
particles are eventually evenly spaced out requires no energy osmosis
diffusion of water across a membrane moves down concentration gradient until concentration on each
side is equal facilitated diffusion
diffusion of solutes across a membrane with the help of transport proteins Tonicity
ability of a solution to cause a cell to gain or lose water Isotonic Solution
concentration of a solute is the same on both sides Hypertonic Solution
concentration of a solute is higher outside the cell Hypotonic Solution
higher concentration of solute inside the cell osmoregulation
process that maintains water balance in cells prevents excessive uptake or loss of water plants have difficulties with osmoregulation due to cell walls
aquaporins hourglassshaped proteins that are responsible for entry and exit of water
through the membrane Active Transport
requires the use of energy / ATP moves a solute against its concentration gradient changes the shape of the protein thru phosphorylation
phosphate from ATP attaches and detaches Transport of Large Molecules
material that is transported is packaged within a vesicle this vesicle then fuses with the membrane
exocytosis export bulky molecules
such as proteins or polysaccharides endocytosis
import substances useful to livelihood of the cell phagocytosis
engulfment of a particle by wrapping cell membrane around it, forming a vacuole
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cell eating pinocytosis
engulfment of a fluid by wrapping cell membrane around it, forming small vesicles
cell drinking receptormediated endocytosis
receptors in a receptorcoated pit interact with a specific protein, initiating formation of a vesicle
Energy and the Cell energy: the capacity to do work and cause change
work is accomplished when an object is moved against an opposing force
kinetic energy: energy of motion performs work by transferring motion to other matter
ex) heat or thermal energy potential energy: energy an object possesses as a result of its location
chemical energy (energy available for release in a reaction) ex) water behind a dam
Laws of Thermodynamics thermodynamics: study of energy transformations
First Law: energy in the universe is constant
Second Law: energy conversions increase the disorder of the universe
entropy: the measure of disorder, or randomness Reaction Classification
exergonic reaction chemical reaction that releases energy
have less free energy energy is released in covalent bonds of reactants
ex) burning wood releases energy in glucose, producing heat, light, carbon dioxide, and water
ex) cellular respiration endergonic reaction
requires an input of energy yields products rich in potential energy
ex) photosynthesis metabolism
the combined makeup of thousands of endergonic and exergonic chemical reactions
metabolic pathway series of chemical reactions that either break down a complex molecule
or build up a complex molecule
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a cell's three main types of cellular work chemical work
driving endergonic reactions transport work
pumping substances across membranes mechanical work
beating of cilia energy coupling
use of exergonic processes to drive an endergonic one cells can manage energy resources this way
ATP adenosine triphosphate: energy currency of cells
immediate source of energy that powers most forms of cellular work composed of:
adenine (nitrogenous base) ribose (5carbon sugar) three phosphate grops
hydrolysis of ATP releases energy by transferring its third phosphate from ATP to another
molecule transfer is called phosphorylation ATP energizes molecules
ATP is a renewable source of energy for the cell How Enzymes Function
energy of activation (Ea) energy available to break bonds and form new ones
enzymes catalysis (speeds us) biological reactions
speed up rate by lowering the Energy of Activation active site
where the enzyme interacts with the enzyme's substrate substrate
particular target molecule of an enzyme nonprotein enzyme helpers
cofactors inorganic such as zinc, iron, or copper
coenzymes organic molecules often vitamins
enzyme inhibitors competitive inhibitors
inhibit because of competition for the active sit block substrates from enetering the active site
noncompetitive inhibitors
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bind somewhere else, changing the shape of the enzyme substrate no longer fits in active site
feedback inhibition regulation of a metabolic pathway by its end product, which inhibits an
enzyme within the pathway Topic 6: Cellular Respiration Harvesting Chemical Energy
Muscle Fibers slow twitch muscle fibers
more myoglobin make ATP aerobically (oxygen) longdistance runners
fast twitch muscle fibers less myoglobin
make ATP anaerobically (without oxygen) sprinters
Metabolic Pathway of Cellular Respiration energy is necessary for life processes
growth, transport, manufacture, movement, reproduction, etc.. photosynthesis and cellular respiration provide energy for life
breathing supplies oxygen to our cells for use in cell respiration it also removes carbon dioxide
cell respiration banks energy in ATP molecules cell respiration produces 38 ATP molecules from each glucose molecule
foods (organic molecules) can be used as a source of energy as well
C6H12O6 + 6O2 > 6CO2 + 6H2O + 38 ATP
Use of energy from ATP
kilocalorie (kcal) quantity of heat required to raise the temperature of 1 kg of water by 1
degree Celsius this energy is used for body maintenance and for voluntary
activities the average adult human needs about 2,200 kcal of energy per day
different activities use different amounts of kcals ex) swimming @ 2mph uses about 408 kcals for a 150lb person
Source of Energy cells tap energy from electrons "falling" from organic fuels to oxygen
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whenthe carbonhydrogen bonds of glucose break, electrons and transferred to oxygen
oxygen attracts electrons energy can be released from glucose by burning it
energy is released as heat and light this energy is not available to living organisms
oxidation loss of electrons
reducation gain of electrons
cell respirations is the controlled breakdown of organic molecules energy is released in small amounts that can be stored in ATP
dehydrogenase enzyme that removes hydrogen from an organic molecule
requires a coenzyme called NAD+ to shuttle electrons NAD+ can be reduced when it accepts e's and oxidized
when it gives them up NAD+ reduced becomes NADH
NAD+ is the electron acceptor it eventually becomes oxidized and is then a donor
electron "carrier" molecules form a staircase where the electrons pass from one to the next down the
staircase these electron carriers are called the electron transport chain
ATP is generated as the electrons are transported down the chain
Stages of Cellular Respiration and Fermentation Glycolysis
begins respiration by breaking glucose into two molecules of a 3carbon compound called pyruvate.
occurs in the cytoplasm Citric Acid Cycle
breaks down pyruvate into carbon dioxide and supplies the third stage with electrons
occurs in the mitochondria Oxidative Phosphorylation
electrons are shuttled through the ETC ; ATP is generated through chemiosmosis
occurs in the inner mitochondrion membrane a concentration gradient of H+ is made during transport
the energy of this gradient is called chemiosmosis it is used to make ATP
the concentration drives H+ through ATP Synthase
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energy/ATP is produce Glycolysis
a single molecule of glucose is cut in half through a series of steps this is done to create two molecules of pyruvate
2 NAD+ molecules are reduced to 2 NADH molecules 2 ATP molecules are produce by substratelevel phosphorylation
substratelevel phosphorylation enzyme transfer a phosphate group from a substrate molecule to ADP
this forms ATP which can be used immediatley NADH must be transported thru the ETC to make more
ATP recycling the ATP
this stage makes 4 ATP, but uses 2 of the ATP's in the cycle they recycle the ATP they use for work
Products 2 Pyruvate 2 ATP (netgain) 2 NADH
Transitional Phase counted into Krebb's Cycle
pyruvate is transported to the mitochondria in preparation for the citric acid cycle...
removal of the carboxyl group that forms CO2 oxidization of the 2carbon compound that remains coenzyme A binds to the 2carbon fragment
this makes acetyl coenzyme A with the help of CoA, the acetyl (2carbon compound) enters the
the citric acid cycle Citric Acid Cycle/Krebb's Cycle
Products: 2 ATP 6 CO2 8 NADH 2 FADH2
Oxidative Phosphorylation involves electron transport and chemiosmosis and requires an adequate supply
of oxygen NADH and FADH2 and the inner membrane of the mitochondria are
involved H+ ion gradient formed from all of the redox reactions provides energy for
synthesis of ATP NADH > 3 ATP
Tommy Wiaduck 2014
10 NADH in stage > 30 ATP FADH> 2 ATP
2 NADH in stage > 4 ATP totals to 34 ATP
hydrogens are pumped outside this is active transport
ATP Synthase "pump"
hydrogen ions enter from top spun around into ATP (adds phosphate) (chemiosmosis)
Products: 34 ATP
Toxins DNP: diet pill (dinitrophenol)
makes you lose weight... but then die of heart attacks makes membrane permeable/leaky hydrogens cannot go thru ATP synthase
cells work harder to get them thru... raises heart rate... DEAD
oligomycin for athlete's foot
blocks/inhibits ATP synthase no ATP is made
fungus dies rotenone
kills plants and fish blocks ETC stops process
cyanide/carbon monoxide works very quickly (cyanide) ; makes you sleepy (carbon
monoxide) stop electron transport chain (ETC) no energy
DEAD Fermentation (Anaerobic)
if no oxygen is present after glycolysis, fermentation undergoes Lactic Acid Fermentation
NADH is oxidized to NAD+ when pyruvate is reduced to lactate produces 2 ATP and 2 Lactate
Alcoholic Fermentation convert pyruvate to CO2 and ethanol while oxidizing NADH to
NAD+ produces 2 Ethanol and 2 ATP (releases 2CO2)
Tommy Wiaduck 2014
Evolution Connection Glycolysis evolved early in the history of life on Earth
it is the universal energyharvesting process of living organisms Interconnections Between Molecular Breakdown and Synthesis
Cells use many kinds of organic molecules as fuel for cellular respiration Three Sources of Molecules for generation of ATP:
Carbohydrates (disaccharides) Proteins (after conversion to amino acids) Fats (glycerol and fatty acids)
Topic 7: Photosynthesis Using Light
Plant Power plants use water and carbon dioxide to produce a simple sugar and liberate
oxygen this is photosynthesis, a process that converts solar energy to chemical
energy plants produce 160 billion metric tons of sugar each year sugar is food for humans and for animals that we consume
biofuels plants can be used in "energy plantations" to create a fuel source to
replace fossil fuels air pollution, acid precipitation, and greenhouse gases would be
reduced 6CO2 + 6H2O light energy> C6H12O6 + 6O2
Producers and Consumers of the Biosphere autotrophs
living things that are able to make their own food without using organic molecules derived from any other living thing
photoautotrophs autotrophs that use the energy of light to produce organic molecules
most plants, algae, and other protists heterotrophs
cannot synthesize their own organic molecules from inorganic raw materials
eat plants or other animals also known as consumers or decompers
Chloroplasts are the sites of Photosynthesis in Plants chlorophyll
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important light absorbing pigment in chloroplasts reflects green light ; thus making plants green
mesophyll green tissue in the interior of the leaf
this is where the chloroplasts are concentrated stomata
tiny pores in the leaf that allow carbon dioxide to enter and oxygen to exit the plant
stroma viscous/dense fluid outside the thylakoids within the chloroplast
enclosed by an envelope of two membranes thylakoids
system of interconnected membranous sacs stacks of thylakoids: grana
Redox Process a redox process involves oxidation and reduction
Photosynthesis is a redox process water molecules are split by oxidation (they lose electrons and
hydrogen ions) CO2 is reduces to sugar as electrons and hydrogens are added to
it Cellular Respiration is also a redox process
see topic 6 for details Overview: The 2 Stages of Photosynthesis are linked by ATP and NADPH
light reactions light energy is converted in the thylakoid membranes to chemical energy
and O2 water is split to provide the O2 as well as electrons NADP+ is reduced by H+ ions to NADPH
electron carrier similar to NADH shuttled into Calvin cycle to make sugar generate ATP
calvin cycle occurs in stroma of the chloroplast
builds sugar molecules from CO2 and the products of light reactions
carbon fixation CO2 is incorporated into organic compounds
also knows as the dark or lightindependent reactions CalvinBenson cycle is also used
The Light Reactions: Converting Solar Energy to Chemical Energy sunlight contains electromagnetic energy or radiation
visible light is only a small section of the electromagnetic spectrum
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the electromagnetic spectrum is the full range of electromagnetic wavelength
wavelength distance between the crests of two adjacent waves
photon packet of light energy
shorter the wavelength, greater the energy pigments
molecules that absorb light pigments are built into the thylakoid membrane they transmit light and absorb others
ex) chlorophyll transmits green this is reflected light, making plants green
responsible for absorbing photons (capturing solar power) electrons jump to an excited state (unstable) drop back down to "ground state"
release excess energy chlorophyll a
absorbs blue violet and red light reflect green
chlorophyll b absorbs blue and orange reflects yellowgreen
carotenoids absorb bluegreen light reflect yellow and orange
Photosystems photosystems are lightharvesting complexes surrounding a reaction center
complex energy is passed from molecule to molecule within the photosystem
it eventually reaches a reaction center where a primary electron acceptor accepts these electrons and becomes reduced
Photosystem II functions first P680
pigment absorbs light with a wavelength of 680 nm Photosystem I
functions second P700
pigment absorbs light with a wavelength of 700 nm Photosystems are connected by the ETC
Chemiosmosis power ATP synthesis in the light reactions it is involved in oxidative phosphorylation and ATP generation in chloroplasts
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photophosphorylation chemiosmotic production of ATP in photosynthesis
Calvin Cycle: Converting CO2 to Sugars The calvin cycle makes sugar within a chloroplast
Ingredients: CO2, ATP, NADPH from light reactions
G3P (glyceraldehyde3phosphate) uses this to make glucose and other organic molecules
RuBP (ribulose biphosphate) fivecarbon sugar that starts the calvin cycle
Carbon Fixation aided by an enzyme called rubisco
this is repeated over and over, one carbon at a time Evolution Connection
C4 and CAM plants hot climates prevent plants from opening stomata during the day
if they did, they would lose water CAM plants open their stomatas in the night when it is cooler
they store CO2 until the day, when they undergo the calvin cycle C4 Plants shut stomata when the weather is hot and dry to conserve
water but is able to make sugar by photosynthesis they first fix carbon dioxide into a 4carbon compound
Photosynthesis, Solar Radiation, and Earth's Atmosphere greenhouse effect
gases in the atmosphere reflect heat back to Earth keeps the planet warm, supporting life
too much heat being retained will result in abnormal temperatures, bringing about problems
global warming slow and steady rise in Earth's surface temperature
melting polar ice, changing weather patterns, spread of tropical disease
photosynthesis moderates global warming it could mitigate the increase in atmospheric CO2
unfortunately, due to deforestation, it will not help
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