Chapter 2

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C

HAPTER

2:

C

HEMISTRY OF

L

IFE

-- Artificial FatsArtificial Fats – – “Olestra”“Olestra”carbohydrate + particular kind of fatcarbohydrate + particular kind of fat is not digested/absorbedis not digested/absorbed

-- Artificial SugarsArtificial Sugars – –19371937‘cyclamate’‘cyclamate’30x sweeter (sucrose)30x sweeter (sucrose) chemical compoundschemical compoundssulfamatessulfamates -- --‘Nutrasweet’‘Nutrasweet’aspartameaspartame200x sweeter200x sweeter

2.1: Nutrients

-- MacromoleculesMacromolecules – –(macro = large) large organic(macro = large) large organic polymerspolymers (poly = many, mer = part)(poly = many, mer = part) large moleculeslarge molecules consisting of many identical or similar

consisting of many identical or similar subunitssubunits ((monomersmonomers connected together).connected together). -- UnityUnity – –only about 40-50 only about 40-50 common monomers are used to construct macromoleculescommon monomers are used to construct macromolecules

-- DiversityDiversity – –new properties emerge when these universal monomers arrange in different ways.new properties emerge when these universal monomers arrange in different ways. -- all permanently made up of elementsall permanently made up of elements C, H, O, NC, H, O, N

-- NutrientsNutrients – –carbohydrates, proteins, and fats (lipids).carbohydrates, proteins, and fats (lipids).

Polymerization Reactions Polymerization Reactions 2+ small monomer molecules

2+ small monomer molecules larger molecules with repeating structural unitslarger molecules with repeating structural units or making 3 dimensionalor making 3 dimensional networks/ polymer chains

networks/ polymer chains Condensation Synthesis/Dehydration Synthesis

Condensation Synthesis/Dehydration Synthesis

Making

Making – – 2+ monomers2+ monomers  covalently linked together;covalently linked together; water molecule removal for each linkage (one loses OH, water molecule removal for each linkage (one loses OH, other loses H)

other loses H)  enables macromolecules. Processenables macromolecules. Process requires energy, catalyst, or enzymes.

requires energy, catalyst, or enzymes.

Hydrolysis Hydrolysis

(hydro = water, lysis = loosening)

(hydro = water, lysis = loosening) – – reaction breaksreaction breaks covalent bonds between monomers and the hydroxyl covalent bonds between monomers and the hydroxyl (neutral OH) bonds to the adjacent monomer.

(neutral OH) bonds to the adjacent monomer.

2.2: Carbohydrates

-- Body’s most important source of energyBody’s most important source of energyorganic molecule made of sugars and organic molecule made of sugars and their polymers (formedtheir polymers (formed by condensation reactants. The classification is based on

by condensation reactants. The classification is based on # of sugars). # of sugars). Structural material-plant cell wallsStructural material-plant cell walls Simple Sugars: Monosaccharides

Simple Sugars: Monosaccharides -- (mono = single, saccar = sugar)(mono = single, saccar = sugar) __contains C, H, O in the ratiocontains C, H, O in the ratio of 1:2:1. Formula = n(CH2O).

of 1:2:1. Formula = n(CH2O).

-- Major nutrients for cellsMajor nutrients for cells glucoseglucosemost common singlemost common single sugar (C6H1206). Can be produced from CO2, H2O + sunlight, sugar (C6H1206). Can be produced from CO2, H2O + sunlight, and can exist in chain form as well as ring form (in nature). Six and can exist in chain form as well as ring form (in nature). Six carbon chain with an aldehyde

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-- FructoseFructoseappears in fruits. Six carbon chain with a ketone.appears in fruits. Six carbon chain with a ketone. -- GalactoseGalactosefound in milk. Six carbon chain with an aldehydefound in milk. Six carbon chain with an aldehyde

(different hydrogen arrangement) (different hydrogen arrangement)

-- DeoxyriboseDeoxyribosesingle sugar component of DNA molecule. Fivesingle sugar component of DNA molecule. Five carbon chain with an a

carbon chain with an a ldehyde.ldehyde.

-- Their carbon skeletons are raw materials for other organicTheir carbon skeletons are raw materials for other organic materials

materials Combining Single Sugars: Disaccharides

Combining Single Sugars: Disaccharides -- MaltoseMaltose2 glucose (malt sugar used in making beer) (starch)2 glucose (malt sugar used in making beer) (starch) -- SucroseSucroseglucose + fructose (table sugarglucose + fructose (table sugar sugar cane)sugar cane) -- LactoseLactoseglucose + galactose (found in milk)glucose + galactose (found in milk)

Complex Carbohydrates: Complex Carbohydrates: Polysaccharides

Polysaccharides

-- StarchStarchmost plantsmost plants2 polysaccharides, amylase,2 polysaccharides, amylase, amylopectin

amylopectinfound in plants, stores energyfound in plants, stores energy

-- CelluloseCellulosemany glucose unitsmany glucose units – –cell walls in plantscell walls in plants -- GlycogenGlycogenresembles starch moleculeresembles starch molecule animals, carbsanimals, carbs

storage (found in liver and in

storage (found in liver and in muscles)muscles) -- Size of carbon skeleton varies 3-7 carbonsSize of carbon skeleton varies 3-7 carbons

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2.3 Lipid

-- 1) fats, oils, waxes, 2) phospholipids, 3) steroids1) fats, oils, waxes, 2) phospholipids, 3) steroids

-- Insoluble in water, only in acetone (nail Insoluble in water, only in acetone (nail polish remover), alcohol, ether, chloroformpolish remover), alcohol, ether, chloroform -- Also has C, H, OAlso hasC, H, Oin different proportions from carbohydratesin different proportions from carbohydrates

-- Glycogen supplies are limitedGlycogen supplies are limited if full, excess carbsif full, excess carbsfatfat Functions

Functions -- Supply EnergySupply Energy difficult for body to break downdifficult for body to break down longer satisfactionlonger satisfaction

-- 1 g of lipid = 2 g carbohydrates or proteins1 g of lipid = 2 g carbohydrates or proteins

-- More compact fuel reservoir than carbsMore compact fuel reservoir than carbs

-- Aids in absorption of vitaminsAids in absorption of vitamins

-- Serves as insulation against heat loss for bodyServes as insulation against heat loss for body

-- Are key components in cell membranesAre key components in cell membranes

-- Cushions organsCushions organs

-- Act as raw materials for synthesis of hormones, other chemicalsAct as raw materials for synthesis of hormones, other chemicals

-- Most common type of lipidMost common type of lipid – – triglyceride = one glycerol molecule + three fatty acids (formed bytriglyceride = one glycerol molecule + three fatty acids (formed by dehydration synthesis reaction)

dehydration synthesis reaction)

-- FATSFATS Saturated

Saturated Fats Fats Unsaturated Unsaturated FatsFats

-- Fatty acidFatty acid  only single bonds betweenonly single bonds between carbon atoms

carbon atoms  maximum number of maximum number of Hydrogen atoms possible on carbon skeleton Hydrogen atoms possible on carbon skeleton

-- Usually solid at room temperatureUsually solid at room temperature

-- Firmer fat (e.g. lard, butter)Firmer fat (e.g. lard, butter)

-- Strong chemical bondsStrong chemical bonds  permit cooking atpermit cooking at higher temperatures

higher temperatures

-- Most animal fatsMost animal fats

-- One or more double bonds between carbons One or more double bonds between carbons inin fatty acid tail, a result of missing Hydrogen fatty acid tail, a result of missing Hydrogen atoms

atoms

-- Tail curves at each C=CTail curves at each C=C  molecules are notmolecules are not packed closely enough to solidify at room packed closely enough to solidify at room temperature, is usually viscous

temperature, is usually viscous

-- Most plant fats (described as polyunsaturated)Most plant fats (described as polyunsaturated)



 corn, peanut, olive oil.corn, peanut, olive oil.

-- React more easilyReact more easilybroken down fasterbroken down faster

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---- HydrogenationHydrogenation – –H atoms added to unsaturated plant fats H atoms added to unsaturated plant fats to make them firmerto make them firmer -- PHOSPHOLIPIDSPHOSPHOLIPIDS – –1 phosphate group + 2 fatty acids + (attached to) glycerol backbone1 phosphate group + 2 fatty acids + (attached to) glycerol backbone

-- Main component - well suited to cell membranes. Polar endMain component - well suited to cell membranes. Polar end soluble in water, 2 fatty acidssoluble in water, 2 fatty acids nonpolarnonpolar



soluble in water. soluble in water. (hydrophilic head, hydrophobic (hydrophilic head, hydrophobic tail)tail)

-- Soap (made from fats treated with lye (NaOH)Soap (made from fats treated with lye (NaOH) dissolves oil and grease in water.dissolves oil and grease in water.

-- STEROIDSSTEROIDS – –C,H,OC,H,Oinsoluble, carbon based, multiple ring structure. Lipids which have four insoluble, carbon based, multiple ring structure. Lipids which have four fused carbonfused carbon rings with various functional groups attached.

rings with various functional groups attached.

-- CholesterolCholesterol – – functionfunction  makes certain hormones (male + female), important part of cell membrane.makes certain hormones (male + female), important part of cell membrane. When combined with other fats, it forms a plaque that blocks blood vessels

When combined with other fats, it forms a plaque that blocks blood vessels  reduced blood flow toreduced blood flow to tissue causes lack of oxygen,

tissue causes lack of oxygen, nutrients = heart disease + circulatory problemsnutrients = heart disease + circulatory problems 2.4

2.4PPROTEINSROTEINS

-- C, H, O, N, sometimesC, H, O, N, sometimes SS atomsatoms

-- Macromolecules made up of amino acidsMacromolecules made up of amino acids Functions

Functions Building Cell StructuresBuilding Cell Structures -- Proteins manufactured (when cells are damaged) or (buildingProteins manufactured (when cells are damaged) or (building

structures for new cells) : proteins created to build red blood

cells = rate at which they die (1 mill/sec). Important in

controlling cellular functions + genetic

controlling cellular functions + genetic operations.operations.

Enzymes

Enzymes -- Proteins: controls rate of many reactionsProteins: controls rate of many reactions digestion, cellulardigestion, cellular

respiration.

Storage of Foods

Storage of Foods -- Emergency situation: can be used as energy sourceEmergency situation: can be used as energy source

-- Composed of 20 amino different amino acids (composed of Composed of 20 amino different amino acids (composed of N, C, H ON, C, H O)(the order and # determine the)(the order and # determine the type)

type)sequencing is regulated by genes located on chromosomes.sequencing is regulated by genes located on chromosomes.

-- GeneGene  patterns of nucleotides (basic structural units of nucleic acid). Each unitpatterns of nucleotides (basic structural units of nucleic acid). Each unit  5 carbon sugar, 15 carbon sugar, 1 phosphate, nitrogenous base.

phosphate, nitrogenous base.

-- Proteins can contain 8-4000 amino acids. There are over a thousand different variations of sequences. AProteins can contain 8-4000 amino acids. There are over a thousand different variations of sequences. A chain of several amino acids

chain of several amino acids polypeptidepolypeptide -- Necessary Amino Acids: 12 : HNecessary Amino Acids: 12 : H uman-madeuman-made

-- Essential Amino Acids: 8: methianine, valine, lysine, tryptophan, threonine, phenylalanine, leucine,Essential Amino Acids: 8: methianine, valine, lysine, tryptophan, threonine, phenylalanine, leucine, isoleucine: must be obtained from food.

isoleucine: must be obtained from food.

---- Denaturation: physical, chemical factors (heat, radiation, change in pH) disrupt bonds between aminoDenaturation: physical, chemical factors (heat, radiation, change in pH) disrupt bonds between amino acids, changing configuration. It may uncoil, assume new shape

acids, changing configuration. It may uncoil, assume new shape  change in physical properties,change in physical properties, biological activities

biological activities Coagulation: permanent. Coagulation: permanent.

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Research in Canada: Proteins Research in Canada: Proteins

-- Membranes of cellsMembranes of cells  linkslinks  receive + transport info, nutrition, medication. The key arereceive + transport info, nutrition, medication. The key are transmembrane proteins (modified proteins, acting as channels for certain ions going in and out of cells transmembrane proteins (modified proteins, acting as channels for certain ions going in and out of cells



shortage or mutation causes diabetes, multiple sclerosis, cystic firbosis, muscular shortage or mutation causes diabetes, multiple sclerosis, cystic firbosis, muscular dystrophy, cancers)dystrophy, cancers) -- Specific molecular structureSpecific molecular structure helps scientists deduce molecular mechanism helps scientists deduce molecular mechanism behind diseases.behind diseases.

-- Dr. DeberDr. Deberisolated + cloned key segments of defective membrane proteinisolated + cloned key segments of defective membrane protein cystic fibrosiscystic fibrosishopes tohopes to gain insight into molecular defects which lead to this disease.

gain insight into molecular defects which lead to this disease. Translation (protein synthesis)

Translation (protein synthesis)

-- The patterns of nucleotides are used as templatesThe patterns of nucleotides are used as templates to build messenger RNA (mRNA) during a process to build messenger RNA (mRNA) during a process called: Transcription. (instructions from DNA called: Transcription. (instructions from DNA copied onto mRNA)

copied onto mRNA)

-- mRNA leaves the nucleus and attaches tomRNA leaves the nucleus and attaches to ribosomes in the cytoplasm (where instructions ribosomes in the cytoplasm (where instructions are read)

are read)

-- the other type of RNA in cytoplasm (transfer RNAthe other type of RNA in cytoplasm (transfer RNA tRNA) is attached to a specific amino acid

tRNA) is attached to a specific amino acid

-- tRNA is brought into positiontRNA is brought into position joins w/ mRNAjoins w/ mRNA

ribosome. Each amino acid is brought into correct ribosome. Each amino acid is brought into correct position to build the protein.

position to build the protein.

-- Amino acid chain growing from ribosomes isAmino acid chain growing from ribosomes is dropped inside endoplasmic reticulum membrane. dropped inside endoplasmic reticulum membrane. Chain folds into protein

Chain folds into protein

-- Protein moves to Golgi Complex for additionalProtein moves to Golgi Complex for additional processing and for sorting

processing and for sorting

-- Protein moves to plasma membrane for exportProtein moves to plasma membrane for export

2.5

2.5NNUCLEICUCLEICAACIDSCIDS

-- DNA and RNADNA and RNAnot nutrientsnot nutrientsessential for lifeessential for life Structure

Structure

DNA RNA

-- Sugars, phosphate groups, 4Sugars, phosphate groups, 4 nitrogenous bases (A adenine, nitrogenous bases (A adenine, G guanine, C cytosine, T G guanine, C cytosine, T thymine). These are bonded thymine). These are bonded together in a subunit together in a subunit 

nucleotide nucleotide

-- Nitrogenous Nitrogenous bases bases of of adjacent DNA nucleotides adjacent DNA nucleotides 

always pair A-T, G-C always pair A-T, G-C

-- Double helix shapeDouble helix shape – – twotwo strands of DNA coiled + strands of DNA coiled + attached with bonds between attached with bonds between nitrogenous bases.

nitrogenous bases.

-- Structure Structure determined determined byby Watson and Crick.

Watson and Crick.

-- Sugars (different one), phosphate groups, 4 nitrogenous basesSugars (different one), phosphate groups, 4 nitrogenous bases (A adenine, G guanine, C cytosine, U uracil)

(A adenine, G guanine, C cytosine, U uracil) -- Single strandSingle strand

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-- Proteins (long chains of amino acids)Proteins (long chains of amino acids) responsible for structural + functional characteristics. Organismsresponsible for structural + functional characteristics. Organisms must contain different proteins. Number an

must contain different proteins. Number an d sequenced sequence unique characteristics.unique characteristics.

-- Sequence of proteinsSequence of proteins determined by sequence of nucleotide bases in segment of DNAdetermined by sequence of nucleotide bases in segment of DNA gene.gene.

-- Each of the genesEach of the genes  codes for production of 1 protein (corresponding sequence of amino acids). Onecodes for production of 1 protein (corresponding sequence of amino acids). One gene, one protein hypothesis.

gene, one protein hypothesis.

-- Each of the amino acidsEach of the amino acids coded by triplet of bases (4cubed = 64 different base triplets possible for thecoded by triplet of bases (4cubed = 64 different base triplets possible for the 20.)

20.) all have more than 1 DNA base triplet codeall have more than 1 DNA base triplet code  a gene on DNAa gene on DNA  has at least 3 times as manyhas at least 3 times as many bases as there are amino acids

bases as there are amino acids in the protein it codes for.in the protein it codes for.

-- Base-pair sequences, number of base pairs in sequence of DNA molecule (thousands of base pairs) areBase-pair sequences, number of base pairs in sequence of DNA molecule (thousands of base pairs) are almost endless

almost endless great diversity in genetic code.great diversity in genetic code. 2.6

2.6TTHEHELLIVINGIVINGCCELLELLMMEMBRANEEMBRANE

-- The cell membrane separates the cell’s protoplasm from The cell membrane separates the cell’s protoplasm from external environmentexternal environmentwhat enters, leaveswhat enters, leaves -- Nutrients from environment, waste builds upNutrients from environment, waste builds up disposeddisposed

-- Structure: bilayer of phospholipids, variety of protein moleculesStructure: bilayer of phospholipids, variety of protein molecules embedded within phospholipid layersembedded within phospholipid layers



 many carry special sugar moleculesmany carry special sugar molecules __ glycoproteinsglycoproteins __ provide cell with unique identityprovide cell with unique identity __ varyvary between organisms

between organisms distinguish type A red blood cell from type distinguish type A red blood cell from type B.B.

-- Immune system recognizes foreign invadersImmune system recognizes foreign invaders unique glycoprotein structureunique glycoprotein structure cell membranecell membrane

-- Protein moleculesProtein molecules  act as gatekeepers (opening and closing pathways), receptor sites for hormonesact as gatekeepers (opening and closing pathways), receptor sites for hormones (chemical messengers

(chemical messengers allow cells to communicate with one another), or transport (using cell energy toallow cells to communicate with one another), or transport (using cell energy to pick up needed materials and move them in

pick up needed materials and move them in and out of cell)and out of cell) Liposomes and Aquaculture

Liposomes and Aquaculture

-- 19651965 – – Alec BanghamAlec Bangham lipids can initiate their own assembly into double-layered spheres the size of alipids can initiate their own assembly into double-layered spheres the size of a cell (liposomes)

cell (liposomes) function like cell membranesfunction like cell membranes can fuse with cell membrane + can fuse with cell membrane + deliver contents.deliver contents. -- Used today to help drugs target tumoursUsed today to help drugs target tumours reduces side effects of drug interactions on reduces side effects of drug interactions on healthy tissues.healthy tissues. -- Enables patientsEnables patientsto accept higher doses of antito accept higher doses of anti -cancer drugs-cancer drugs

-- Liposomes as deliveryLiposomes as delivery efficiency of gene therapyefficiency of gene therapy introducing new genes into DNA to introducing new genes into DNA to correct geneticcorrect genetic flaws/disease

flaws/disease 2.7

2.7PPASSIVEASSIVETTRANSPORTRANSPORT

Passive Transport

-- Movement of materials across cell membrane without the use of energy from the cellMovement of materials across cell membrane without the use of energy from the cell

Diffusion: net Diffusion: net movement of movement of

-- Molecules moving from area of high concentrationMolecules moving from area of high concentration lowlowresult of Brownian motion:result of Brownian motion: random movement of molecules in gas or solution.

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particles particles down an down an electrochemi electrochemi cal gradient cal gradient (give up (give up potential potential energy) energy)

-- Diffusion rates increaseDiffusion rates increase  hotter temperature (liquid)hotter temperature (liquid)  pressure increases (gas)pressure increases (gas) 

molecules are bunched close together, collide more frequently. Therefore, gas

molecules are bunched close together, collide more frequently. Therefore, gas  highhigh pressure

pressurelow pressure.low pressure.

-- Diffusion affected byDiffusion affected by  concentration, temperature, pressure (continues until equalconcentration, temperature, pressure (continues until equal distribution)

distribution)

-- Oxygen + CO2 move across cell membranesOxygen + CO2 move across cell membranes diffusion.diffusion. OO diffuses from blooddiffuses from blood areasareas of high

of high low concentration in the cell.low concentration in the cell. CO2CO2accumulates inside cellaccumulates inside cell diffuses fromdiffuses from cell

cellblood.blood. Osmosis: Osmosis: diffusion of diffusion of water across water across a selectively a selectively permeable permeable membrane membrane

-- WaterWater  follows concentration gradientfollows concentration gradient – – difference in # of molecules or ions of adifference in # of molecules or ions of a substance between adjoining regions. Molecules tend to diffuse

substance between adjoining regions. Molecules tend to diffuse – –high concentrationhigh concentration 

low. low.

-- WaterWater  side B to side Aside B to side A  concentration of water molecules + protein molecules =concentration of water molecules + protein molecules = equal

equalequilibrium. (all acting influences are balancedequilibrium. (all acting influences are balanced stable environment).stable environment).

-- Ideally, cells are bathed in isotonic solutions (solute concentration outside cell = thatIdeally, cells are bathed in isotonic solutions (solute concentration outside cell = that inside of cell).

inside of cell).

-- Blood keeps internal environment in homeostatis (keeping isotonic balanceBlood keeps internal environment in homeostatis (keeping isotonic balance constantconstant internal environment).

internal environment).

-- Hypotonic solutionHypotonic solution  lower concentration of solutelower concentration of solute  higher concentration of waterhigher concentration of water than inside cell. Water moves inside cell. In freshwater, organisms have developed ways than inside cell. Water moves inside cell. In freshwater, organisms have developed ways of expelling water

of expelling water contractile vacuole.contractile vacuole.

-- Hypertonic solution (greater)Hypertonic solution (greater)  concentration of solutesconcentration of solutes  higher than in cell +higher than in cell + concentration of water

concentration of water – –lower. Water moves out by osmosis. * Turgor pressurelower. Water moves out by osmosis. * Turgor pressure waterwater pressure.

pressure.

-- Seen from the extracellular fluid point of Seen from the extracellular fluid point of view (ECF)view (ECF) Facilitated

Facilitated Diffusion Diffusion

-- Protein carrier molecules in cell membraneProtein carrier molecules in cell membrane aid in passive transport. They speed up aid in passive transport. They speed up thethe movement of molecules already moving across c

movement of molecules already moving across c ell membrane. (e.g. glucose diffuses intoell membrane. (e.g. glucose diffuses into red blood cells 100x faster than other sugar molecules

red blood cells 100x faster than other sugar molecules  carrier proteins must becarrier proteins must be specialized to aid diffusion).

specialized to aid diffusion).

-- 3 ways to enter cell: through phospholipid bilayer, protein channels, facilitated 3 ways to enter cell: through phospholipid bilayer, protein channels, facilitated diffusion.diffusion.

--2.8

2.8AACTIVECTIVETTRANSPORTRANSPORT

Molecular Active Transport

-- Cell uses energy to move from lowCell uses energy to move from low high concentration (against concentration high concentration (against concentration gradient). Happensgradient). Happens

while you sleep, (30% -

while you sleep, (30% - 40% of total energy budget) (uses ATP energy)40% of total energy budget) (uses ATP energy)

-- Exocytosis ProcessExocytosis Process  cells ingest materials too large forcells ingest materials too large for transport carrier molecules. Membrane folds around material, transport carrier molecules. Membrane folds around material, trapping ingested particle in pouch/vacuole inside cytoplasm. trapping ingested particle in pouch/vacuole inside cytoplasm. Enzymes from lysosomes

Enzymes from lysosomesused to digest molecules. 2 types:used to digest molecules. 2 types: -- PinocytosisPinocytosis – – cells take up dissolved molecules by engulfingcells take up dissolved molecules by engulfing

small volumes of external solution (liquid droplets). (e.g. cells small volumes of external solution (liquid droplets). (e.g. cells in small intestine

in small intestine fat droplets)fat droplets)

-- PhagocytosisPhagocytosis  engulf solid particles. White blood cellsengulf solid particles. White blood cells 

phagocytes (eater cells)

phagocytes (eater cells) consume invading microbes. Theseconsume invading microbes. These are trapped in vacuole

are trapped in vacuole  digested when vacuole fuses withdigested when vacuole fuses with lysosomes.

lysosomes.

-- Some membrane proteinsSome membrane proteins  unique shape to match specificunique shape to match specific molecules in endocytosis

molecules in endocytosis

-- Exocytosis: Exocytosis: large large moleculesmolecules within the cell

within the cell  transportedtransported out (waste, transmitter out (waste, transmitter chemicals from nerve cells) chemicals from nerve cells) -- Golgi apparatusGolgi apparatus  fuse withfuse with

cell membrane + material cell membrane + material 

released released

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