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Bio 3: ch
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 A major hydrocarbon component called a fatty acid
 A hydrocarbon chain bonded to a carboxyl functional group
 Isoprene: large fatty acid hydrocarbon chain
 Cis- double bonds that cause kinks in hydrocarbon chains
 Causes trans fats
 Saturated and Unsaturated Fart Acids:
o Saturated lipids-stays solid in room temperature (butter)
o Saturated lipids with hydrocarbon tails- a lipid that is very long hydrophobic saturated
hydrocarbon tails wax (bees wax)
o Unsaturated fats- stays liquid at room temperature due to the kinks in the chain (cis
unsaturated fats) (oils)
 3 types of lipids found in cells
o Lipid structure is characterized by physical properties
 Their insolubility in water
 instead of a shared chemical structure
o Insolubility is based on:
 The high proportion of nonpolar C-C and C-H bonds
 Relative to polar functional groups
o 3 most important types of lipids:
 Fats (triacylglycerols, triglycerides)
 Steroids
 Phospholipids
 Structure of fats:
o Composed of three fatty acids linked to glycerol
 Also called triaclyglycerols and triglycerides
o When fatty acids are polyunsaturated
 Form liquid triacylglycerols called oils
 The primary role of fats is energy storage
o Fats form when:

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A dehydration reaction occurs between a hydroxyl group of glycerol & the carboxyl
group of a fatty acid
 The glycerol and fatty acid molecules become joined by an ester linkage
Structure of Steroids:
o A family of lipids
o Distinguished by a bulky, four ring structure
o Differ from one another by The functional groups or side groups attached to different carbons in those
hydrophobic rings
o Cholesterol- a hydrophilic hydroxyl group attached to the top ring and an isoprenoid "tail"
attached at the bottom
 It is an important component of plasma membranes in many organisms
Structure of Membrane Lipids:
o Membrane forming lipids contain A polar hydrophilic region
 And a nonpolar hydrophobic region
o Phospholipids are amphipathic
 The head region contains highly polar covalent bonds
 Has a glycerol, a phosphate, and a charged group
 The tail region is comprised of two nonpolar fatty acid or isoprene chains
o When placed in a solution these lipids form membranes
 The phospholipid heads interact with th water
 The tails do not
Phospholipids in Water:
o Do not dissolve in water
 Water cannot form the hydrogen bonds it needs
o Water molecules interact
 With the hydrophilic heads
 Not the hydrophobic tails
 This drives the hydrophobic tails together
o Upon contact with water phospholipids form either:
 Micelles- heads face water and tails face each other
 Phospholipid bilayers
 Form when:
 Two sheets of phospholipid molecules align
 Hydrophilic heads align
 The hydrophobic tails face each other
 Forms spontaneously
 No input of energy is needed
Artificial Membranes as an Experimental System:
o Hydrophilic heads on both sides of bilayers
 Remain in contact with aqueous solution
 Water is present both inside and outside
o Artificial Membrane bound vesicles like these are called liposomes
o Planer bilayers Lipid bilayers constructed along holes to see what will be allowed through them
Selective Permeability of Lipid Bilayers:
o Permeability of a structure is its tendency to allow a given substance inside

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Highly selective
Phospholipid bilayers have selective permeability
 Small or nonpolar molecules move across quickly
 Charged or large polar substances cross slowly if at all
 Many factors affect Membrane permeability
o The number of double bonds between carbons in the hydrophilic tail
o Length of the tail
o Number of cholesterol molecules in membrane
o temperature
 Bond Saturation and Permeability
o Double bonds in chain cause a kink
 Prevents the close packing of hydrocarbon tails
 Reduces hydrophobic interactions
o Unsaturated hydrocarbon chains
 Have at least one double bond
 Membranes are much more permeable
 Other factors affecting permeability
o Hydrophobic interactions become stronger
 Tails increase in length
 Longer tails reduce permeability
o Decreasing temp
 Molecules move more slowly
 Decreases fluidity equals decreased permeability
Chapter 7 Cell Structure
 All cells have:
o Nucleic acids- store and transmit info
o Proteins- perform cells functions
o Carbohydrates- chemical energy, carbon, support, identity
o Plasma membrane- selectively permeable membrane
 According to morphology: two broad groups
o Prokaryotes- lack membrane bound organelles
o Eukaryotes- have a nucleus
 3 Domains according to phylogeny
o Bacteria- pro
o Archaea- pro
o Eukarya
 Prokaryotes:
o Lack nucleus
o Recently revealed more complex than originally thought
o Archaea structure is still poorly understood
o Bacteria cells greatly vary in size
o Most bacteria contain several structural similarities
 Plasma membrane
 Single chromosome
 Ribosomes that synthesize proteins
 Stiff cell wall
 Cytoplasm
o Most have one supercoiled chromosome

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In the nucleoid region
Contains long strand of DNA
Supportive proteins
Coils very titely on itself
o Many also contain plasmids
 Small supercoiled DNA
 Help the cell to adapt
 Physically independent from the chromosome
o Other structures are contained within cytoplasm:
 Ribosomes- consist of RNA molecules and protein
 Used for protein synthesis
o Internal photosynthetic membranes
o Cytoskeleton
 Support the cell inside by a network of long, thing protein filaments
o All energetic reactions happen along a membrane in all cells
o Recently discovered that there are internal compartments within Bacteria
 Qualify as organelles " little organelles"
o Bacterial organelles perform an array of tasks
 Store calcium or key ions
 Holding crystals that act as compass
 Organized enzymes
 Sequestering enzymes
o Plasma Membrane:
 Phospholipid bilayer
o Inside membrane is all cell contents
 Collectively called cytoplasm
o Cell wall forms protective exoskeleton
 Most pro's have a cell wall
 Composed of tough fibrous layer
 Surround the plasma membrane
o Many also have another layer
 Outside cell wall called glycolipids
o Some have tail like flagella
 On cell surface
 Spin around to move the cell
o Base of this structure
 Embedded in plasma membrane
 Rotation spins along a helical filament
 Propels through water
o Fimbriae (fimbria singular) - think Velcro
 Needlelike projections
 Extend from plasma membrane
 Promote attachment to other cells
Eukaryotes: range in size from very small to very large
o Many are multicellular with a few unicellular
o Larger than prokaryotes
o Size makes it hard for molecules to diffuse across entire thing
o Solved by breaking volume into several membrane bound organelles

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This offers two advantages
 Separation of incompatible chemical reactions
 Increases chemical reaction efficiency
Four key differences:
 Eukaryotic chromosomes found in nucleus
 Much larger
 Contain extensive amounts of membrane
 Diverse dynamic cytoskeleton
 Pg
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 Pinocytosis brings fluid into the cell
 Vacuoles:

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Structure- large, membrane bound structures found in plant and fungi cells
Function Some are for digestion
 Most are for storage of water and/or ions
 To help maintain its normal volume
 Inside seeds they are filled with proteins
 In flower petals or fruits they kicontain pigments
 May contain toxic compounds to keep predators away
Peroxisomes:
 Structure- globular organelles bounds by single membrane
 Originate as buds in the ER
 Function- center for oxidation reactions
 Liver cell peroxisomes contain enzymes that remove electrons from or oxidize
the ethanol in alcohol
 Specialized ones in plants called glyoxysomes
Mitochondria:
 Structure- have two membranes
 Inner one is folded sack of cristae
 Is called the mitochondrial matrix
 Have their own DNA
 Manufacture own ribosomes
 Function- ATP production is core function

Over view of cellular respiration
 All organisms use glucose to build fats, carbs, and other compounds
 Cells recover glucose by breaking down these molecules
o Glucose is used to make ATP through CR or fermentation
 CR produces ATP from a molecule with high PE-usually glucose
 4 Steps
o Chemical reactions
o Distinctive starting molecule
o Characteristics set of products
 When Glucose is Oxidized
o Carbon atoms of glucose are oxidized to form CO2
o Oxygen atoms on O2 are reduced to form water
o Glucose is oxidized through aa long series of carefully controlled redox reactions
o Result change is free energy is used to synthesize ATP, ADP, etc
 Steps of CR
o CR is any set of reactions that produces ATP in an electron transport chain
o 4 steps:
 Gylcolysis - broken down to form pyruvate
 Pyruvate processing
 Citric Acid Cycle (crebs cycle)- Acetly CoA is oxidized to CO2
 Electron tranposrt and chemiosmosis
 CR Interacts with metabolic pathways
o Energy and carbon

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Two fundamental requirements
Need high energy electrons for generating chemical energy (ATP)
o Catabolic pathways- break molceules down and make ATP
o Anabolic pathways- results in synthesis of larger molecules from smaller components
For ATP productions cells
o First use carbs
o Then fats
o And finally proteins
Proteins, carbs, and fats can all furnish aubstrates for cellular respiration
Processing proteins and fats as fuel
o Enzymes remove the amino groups from proteins
 Remaining carbs are intermeidiates
 Used in glycolysis
o Enzymes break down fats
 Form glycerol
 Enters glycolytic pathways
 To form acetly CoA
 Enters citric acid cycle
Methods of producing ATP
o Subatrate level phosphoaralation
Feedback inhibition
o Occurs when an enzyme in a pathway is inhibited by an abundance of products
Pyruvate Processing
o Produced during glycolysis
o Transported from cytosol into mitochondria
o Mitochondria have both inner and outer membrane
 Criatae and matrix



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