Chemistry of Chemistry of Life: Part 1Life: Part 1

AHSGE Science Standards (See AHSGE Science Standards (See Handout)Handout)

2a Identify functions of 2a Identify functions of carbohydrates, lipids, proteins and carbohydrates, lipids, proteins and nucleic acids in cellular activities.nucleic acids in cellular activities.

3 Identify reactants and products 3 Identify reactants and products associated with photosynthesis and associated with photosynthesis and cellular respiration and the cellular respiration and the purposes of these two processes.purposes of these two processes.

I. Chemistry of the Cell : Key ElementsI. Chemistry of the Cell : Key Elements

A. An A. An elementelement is a type is a type of matter composed of of matter composed of only one kind of atom only one kind of atom which cannot be broken which cannot be broken down to a simpler down to a simpler structure.structure.

I. Chemistry of the Cell : Key ElementsI. Chemistry of the Cell : Key ElementsB. The following six B. The following six elements are commonly elements are commonly found in living cells: found in living cells: sulfur, sulfur, phosphorous, oxygen, phosphorous, oxygen, nitrogen, carbon, & nitrogen, carbon, & hydrogenhydrogen ( (SPONCHSPONCH). ). See See Figure 3.1 Key Elements of Figure 3.1 Key Elements of Living CellsLiving Cells

I. Chemistry of the Cell : Key ElementsI. Chemistry of the Cell : Key Elements

C. These elements C. These elements make up 99% of all make up 99% of all living tissue & combine living tissue & combine to form the molecules to form the molecules that are the basis of that are the basis of cellular function.cellular function.

I. Chemistry of the Cell : Key ElementsI. Chemistry of the Cell : Key ElementsD. CarbonD. Carbon

–1. Carbon is especially important 1. Carbon is especially important because 1 carbon atom can because 1 carbon atom can make covalent bonds with 4 make covalent bonds with 4 other atoms, resulting in the other atoms, resulting in the formation of very stable & formation of very stable & complex structures.complex structures.

–2. Carbon is in all living things as 2. Carbon is in all living things as well as in the remains of living well as in the remains of living things.things.

I. Chemistry of the Cell : Key ElementsI. Chemistry of the Cell : Key ElementsE. Molecules containing E. Molecules containing

carbon are called carbon are called organic organic moleculesmolecules, while those without , while those without carbon are called carbon are called inorganic inorganic moleculesmolecules..

F. Cellular reactions occur in F. Cellular reactions occur in great part between biological great part between biological molecules called molecules called biomoleculesbiomolecules..

I. Chemistry of the Cell : Key ElementsI. Chemistry of the Cell : Key Elements

G. The 4 primary classes of G. The 4 primary classes of cellular biomolecules are cellular biomolecules are carbohydrates, lipids, proteinscarbohydrates, lipids, proteins and and nucleic acidsnucleic acids..

H. Each of these is a H. Each of these is a polymerpolymer, , a long chain of small repeating a long chain of small repeating units called units called monomersmonomers. .

II. CarbohydratesII. Carbohydrates

II. CarbohydratesII. CarbohydratesA. Carbohydrates are often A. Carbohydrates are often

called sugars and are an energy called sugars and are an energy source.source.

B. Structurally, they are chains B. Structurally, they are chains of carbon units with hydroxyl of carbon units with hydroxyl groups (-OH) attached.groups (-OH) attached.

C. The simplest carbohydrates C. The simplest carbohydrates are monosaccharides.are monosaccharides.

II. CarbohydratesII. CarbohydratesD. The ends of these D. The ends of these sugars bond & unbond sugars bond & unbond continuously, so that the continuously, so that the straight chain & cyclic (ring-straight chain & cyclic (ring-like) forms are in like) forms are in equilibrium. equilibrium. See Figure 3.2 See Figure 3.2 Fischer diagram of glucose Fischer diagram of glucose & Figure 3.3 Ribose& Figure 3.3 Ribose

II. CarbohydratesII. CarbohydratesE. These monosaccharides E. These monosaccharides

may join together to form may join together to form disaccharides (2), disaccharides (2), oligosaccharides (3-10) or oligosaccharides (3-10) or polysaccharides (10+), polysaccharides (10+), depending on how many depending on how many monosaccharides make up monosaccharides make up the polymeric carbohydrate.the polymeric carbohydrate.

II. CarbohydratesII. CarbohydratesF. ExamplesF. Examples

– 1. 1. MonosaccharidesMonosaccharides – fructose & – fructose & glucoseglucose

– 2. 2. DisaccharidesDisaccharides – sucrose (table – sucrose (table sugar)sugar)

– 3. 3. OligosaccaridesOligosaccarides – no common – no common namesnames

– 4. 4. PolysaccaridesPolysaccarides – starch & – starch & cellulose (complex carbs)cellulose (complex carbs)

III. LipidsIII. Lipids

III. LipidsIII. LipidsA. A. Lipids Lipids are fats, made up of are fats, made up of

chains of methylene (-CHchains of methylene (-CH22) ) units.units.

B. The chains may be long or B. The chains may be long or short, & they may be straight short, & they may be straight or fused into rings (cyclic).or fused into rings (cyclic).

C. They function as fat C. They function as fat molecules that store energy.molecules that store energy.

III. LipidsIII. LipidsD. They are structural D. They are structural

components of the cell components of the cell membrane.membrane.

E. Important lipids include: E. Important lipids include: waxes, steroids, fatty acids & waxes, steroids, fatty acids & triglicerides. triglicerides. See Figure 3.4 See Figure 3.4 LipidsLipids

F. Example – butterF. Example – butter

IV. ProteinsIV. ProteinsA. Proteins consist of long, linear A. Proteins consist of long, linear

chains of chains of polypeptidespolypeptides..–1. The polypeptide is a chain of 1. The polypeptide is a chain of amino acidsamino acids monomers. monomers.

B. There are 20 standard amino B. There are 20 standard amino acids which combine to form acids which combine to form every single protein needed by every single protein needed by the human body. the human body. See Figure 3.5 See Figure 3.5 Polypeptide & Figure 3.6 ProteinPolypeptide & Figure 3.6 Protein

IV. ProteinsIV. ProteinsC. Since mammals cannot C. Since mammals cannot

make all 20 amino acids make all 20 amino acids themselves, they must eat themselves, they must eat protein in order to maintain a protein in order to maintain a healthy diet.healthy diet.

D. Examples – animals D. Examples – animals (meat) & vegetables (beans)(meat) & vegetables (beans)

V. Nucleic AcidsV. Nucleic Acids

V. Nucleic AcidsV. Nucleic AcidsA. Nucleic acids are found in the A. Nucleic acids are found in the

nucleus of a cell.nucleus of a cell.B. The nucleic acid polymer is B. The nucleic acid polymer is

made up of made up of nucleotidenucleotide monomers.monomers.–1. The nucleotide monomer 1. The nucleotide monomer

consists of a sugar, a phosphate consists of a sugar, a phosphate group & a nitrogenous base. group & a nitrogenous base. See Figure 3.7 A NucleotideSee Figure 3.7 A Nucleotide

V. Nucleic AcidsV. Nucleic AcidsC. Nucleic acids are the backbone C. Nucleic acids are the backbone

of the following genetic material:of the following genetic material:–1. 1. DNA (deoxyribonucleic acid)DNA (deoxyribonucleic acid)

directs the activities of the cell directs the activities of the cell & contains the sugar & contains the sugar deoxyribose. deoxyribose.

–2. 2. RNA (ribonucleic acid)RNA (ribonucleic acid) is is involved in protein synthesis & involved in protein synthesis & contains the sugar ribose.contains the sugar ribose.

V. Nucleic AcidsV. Nucleic Acids

D. The bulk of the D. The bulk of the cell is made up of cell is made up of water. water. See Figure See Figure 3.8 Composition of 3.8 Composition of the Cellthe Cell

Complete the Section Complete the Section Review 1: The Review 1: The

Chemistry of the CellChemistry of the Cell

Cells & Cellular Cells & Cellular Transport: Transport:

Part 2Part 2

VI. SolutionsVI. SolutionsA. A A. A solutionsolution is a liquid is a liquid

mixture of mixture of solutesolute dissolved in dissolved in solventsolvent..–Example – Think of salt Example – Think of salt water, a solution in which water, a solution in which salt (solute) is dissolved in salt (solute) is dissolved in water (solvent).water (solvent).

VI. SolutionsVI. SolutionsB. The interior of a cell is B. The interior of a cell is also a solution.also a solution.

C. The cytoplasm is a C. The cytoplasm is a watery jelly-like substance watery jelly-like substance (solvent) that contains a (solvent) that contains a variety of substances variety of substances (solutes).(solutes).

VI. SolutionsVI. SolutionsD. Maintaining the concentration D. Maintaining the concentration

of solutes in the cytoplasm is of solutes in the cytoplasm is critical to cell function.critical to cell function.

E. This ideal balance of solutes E. This ideal balance of solutes within the cell is a state the cell within the cell is a state the cell strives to maintain through a strives to maintain through a variety of mechanisms.variety of mechanisms.–1. This process is called 1. This process is called

homeostasishomeostasis..

VII. Cell MembraneVII. Cell Membrane

VII. Cell MembraneVII. Cell MembraneA. The main purpose of the cell A. The main purpose of the cell

membrane is to regulate the membrane is to regulate the movement of materials into & movement of materials into & out of the cell.out of the cell.

B. The membrane is B. The membrane is semi-semi-permeable,permeable, or or selectively selectively permeablepermeable, meaning that only , meaning that only certain substances can go certain substances can go through.through.

VII. Cell MembraneVII. Cell Membrane C. The cell C. The cell

membrane is membrane is composed of a composed of a phospholipid bilayer. phospholipid bilayer. See Figure 2.9 See Figure 2.9 Phospholipid BilayerPhospholipid Bilayer– 1. Each 1. Each

phospholipid layer phospholipid layer consists of consists of phosphate groupsphosphate groups attached to 2 fatty attached to 2 fatty acid tails. acid tails.

VII. Cell MembraneVII. Cell Membrane–2. The layers arrange 2. The layers arrange themselves so that the themselves so that the phosphate heads are on the phosphate heads are on the outer edges of the outer edges of the membrane, & the fatty acid membrane, & the fatty acid tails compose the interior of tails compose the interior of the membrane.the membrane.

VII. Cell MembraneVII. Cell Membrane–3. Globular proteins used for 3. Globular proteins used for various functions are various functions are embedded in the cell embedded in the cell membrane.membrane.

–4. The phospholipids are free 4. The phospholipids are free to move around allowing the to move around allowing the membrane to stretch & change membrane to stretch & change shape.shape.

VIII. Cellular TransportVIII. Cellular TransportA. A. Passive TransportPassive Transport

–1. Passive transport is 1. Passive transport is spontaneous & does not require spontaneous & does not require energy.energy.

–2. Molecules move 2. Molecules move spontaneously through the cell spontaneously through the cell membrane from areas of higher membrane from areas of higher concentration to areas of lower concentration to areas of lower concentration.concentration.

VIII. Cellular TransportVIII. Cellular Transport

–3. They move with the 3. They move with the concentration gradient. concentration gradient.

–4. The 3 types of passive 4. The 3 types of passive transport are transport are diffusiondiffusion, , facilitated diffusionfacilitated diffusion, & , & osmosisosmosis..

VIII. Cellular TransportVIII. Cellular TransportB. Diffusion is the process by B. Diffusion is the process by

which substances move directly which substances move directly through the cell membrane. through the cell membrane. See See Figure 2.10 DiffusionFigure 2.10 Diffusion

C. Facilitated diffusion involves C. Facilitated diffusion involves the help of a carrier protein to the help of a carrier protein to move a substance from 1 side of move a substance from 1 side of the cell wall to the other.the cell wall to the other.

VIII. Cellular TransportVIII. Cellular TransportE. Osmosis is the movement E. Osmosis is the movement

of water from an area of high of water from an area of high water concentration to an water concentration to an area of low water area of low water concentration through a semi-concentration through a semi-permeable membrane. permeable membrane. See See Figure 2.11 OsmosisFigure 2.11 Osmosis

VIII. Cellular TransportVIII. Cellular Transport–1. Osmosis is the 1. Osmosis is the diffusion of water.diffusion of water.

–2. Osmosis can occur in 2. Osmosis can occur in either direction depending either direction depending on the concentration of on the concentration of dissolved material inside dissolved material inside & outside the cell.& outside the cell.

VIII. Cellular TransportVIII. Cellular Transport–3. Defining the solution 3. Defining the solution concentrations relative to 1 concentrations relative to 1 another will predict the another will predict the direction in which osmosis will direction in which osmosis will occur.occur.

–4. Diffusion of water (osmosis) 4. Diffusion of water (osmosis) across a cell membrane always across a cell membrane always occurs from hypotonic to occurs from hypotonic to hypertonic.hypertonic.

VIII. Cellular TransportVIII. Cellular Transport–5. 3 situations are 5. 3 situations are possible:possible:a. a. Hypotonic SolutionHypotonic Solutionb. b. Hypertonic SolutionHypertonic Solutionc. c. Isotonic SolutionIsotonic Solution

a. Hypotonic Solutiona. Hypotonic Solution– 1) The solution surrounding the cell 1) The solution surrounding the cell

membrane has a lower concentration membrane has a lower concentration of dissolved substances than the of dissolved substances than the solution inside the cell membrane.solution inside the cell membrane.

– 2) The solution outside the 2) The solution outside the membrane is hypotonic with respect membrane is hypotonic with respect to the solution inside the cell to the solution inside the cell membrane.membrane.

– 3) The cell will experience a net gain 3) The cell will experience a net gain of water & swell. of water & swell. See Figure 2.12 See Figure 2.12 Possible Results of OsmosisPossible Results of Osmosis

b. Hypertonic Solutionb. Hypertonic Solution– 1) The solution surrounding the cell 1) The solution surrounding the cell

membrane has a higher concentration membrane has a higher concentration of dissolved solute than the solution of dissolved solute than the solution inside the cell membrane.inside the cell membrane.

– 2) The solution outside the membrane 2) The solution outside the membrane is hypertonic with respect to the is hypertonic with respect to the solution inside the cell membrane.solution inside the cell membrane.

– 3) The cell will lose water to its 3) The cell will lose water to its surroundings causing it to shrink. surroundings causing it to shrink. See See Figure 2.12Figure 2.12

c. Isotonic Solutionc. Isotonic Solution–1) The concentration of dissolved 1) The concentration of dissolved

solutes is the same inside the cell solutes is the same inside the cell as it is outside the cell.as it is outside the cell.

–2) These solutions are said to be 2) These solutions are said to be isotonic with respect to each isotonic with respect to each other.other.

–3) There will be no net movement 3) There will be no net movement of water across the cell of water across the cell membrane. membrane. See Figure 2.12See Figure 2.12

VIII. Cellular TransportVIII. Cellular TransportF. Placing plant cells in a F. Placing plant cells in a

hypotonic solution causes the hypotonic solution causes the plant cell membranes to plant cell membranes to shrink away from the cell shrink away from the cell wall.wall.–1. This process is called 1. This process is called plasmolysisplasmolysis..

VIII. Cellular TransportVIII. Cellular Transport

–2. Plasmolysis can result 2. Plasmolysis can result in plant cell death due to in plant cell death due to water loss.water loss.

–3. A wilted plant is 3. A wilted plant is showing signs of showing signs of plasmolysis.plasmolysis.

VIII. Cellular TransportVIII. Cellular TransportG. Placing a plant in a G. Placing a plant in a

hypertonic solution has an hypertonic solution has an opposite effect:opposite effect:–1. The cell will swell until the 1. The cell will swell until the cell wall allows no more cell wall allows no more expansion.expansion.

–2. The plant now becomes 2. The plant now becomes very stiff & turgid.very stiff & turgid.

Turgid & Plasmolysed

VIII. Cellular TransportVIII. Cellular TransportH. H. Active TransportActive Transport

–1. The cell may need to move 1. The cell may need to move material across the cell membrane material across the cell membrane against the concentration against the concentration gradient.gradient.

–2. The cell must expend energy.2. The cell must expend energy.–3. The movement of substances 3. The movement of substances

from an area of low concentration from an area of low concentration to an area of high concentration is to an area of high concentration is called active transport.called active transport.

VIII. Cellular TransportVIII. Cellular Transport

–4. The movement is 4. The movement is characterized by its characterized by its directionality.directionality.a. a. ExocytosisExocytosisb. b. EndocytosisEndocytosis

VIII. Cellular TransportVIII. Cellular Transporta. Exocytosisa. Exocytosis

–1) Exocytosis is a form of 1) Exocytosis is a form of active transport that removes active transport that removes materials from the cell.materials from the cell.

–2) A sac stores the material 2) A sac stores the material to be removed from the cell, & to be removed from the cell, & then moves near the cell then moves near the cell membrane.membrane.

VIII. Cellular TransportVIII. Cellular Transport–3) The cell membrane opens, & 3) The cell membrane opens, &

the substance is expelled from the substance is expelled from the cell. the cell.

–4) Waste materials, proteins, & 4) Waste materials, proteins, & fats are examples of materials fats are examples of materials removed from the cell this way. removed from the cell this way. See Figure 2.13 Schematic of See Figure 2.13 Schematic of Exocytosis & EndocytosisExocytosis & Endocytosis

VIII. Cellular TransportVIII. Cellular Transportb. Endocytosisb. Endocytosis

– 1) Endocytosis, another form of 1) Endocytosis, another form of active transport, brings materials active transport, brings materials into the cell without passing into the cell without passing through the cell membrane.through the cell membrane.

– 2) The membrane folds itself 2) The membrane folds itself around the substance, creates a around the substance, creates a vesicle & brings the substance into vesicle & brings the substance into the cell.the cell.

VIII. Cellular TransportVIII. Cellular Transport–3) Some unicellular 3) Some unicellular organisms, such as an organisms, such as an amoeba, obtain food this amoeba, obtain food this way. way. See Figure 2.13 See Figure 2.13 Schematic of Exocytosis Schematic of Exocytosis & Endocytosis& Endocytosis

Exocytosis & EndocytosisExocytosis & Endocytosis

IV. Factors Affecting Cellular ActivityIV. Factors Affecting Cellular ActivityA. Cellular activity (metabolism, A. Cellular activity (metabolism,

reproduction, & movement) is reproduction, & movement) is affected by several factors: affected by several factors: – 1. Cells cannot grow to extremely 1. Cells cannot grow to extremely

large sizes due to the ratio large sizes due to the ratio between cellular surface area & between cellular surface area & internal cell volume.internal cell volume.

– 2. Environmental factors 2. Environmental factors (temperature, light, & pH) affect (temperature, light, & pH) affect cellular activity.cellular activity.

V. Fluid PressureV. Fluid PressureA. A. Fluids Fluids

–1. Fluids are liquids & gases.1. Fluids are liquids & gases.–2. The collisions of the particles 2. The collisions of the particles against the surface of the against the surface of the container cause the gas or container cause the gas or liquid to exert pressure upon liquid to exert pressure upon the container. the container. See Figure 2.14 See Figure 2.14 Particle Motion in GasesParticle Motion in Gases

V. Fluid PressureV. Fluid PressureB. B. PressurePressure

–1. Pressure is a force (push or 1. Pressure is a force (push or pull) applied uniformly over an pull) applied uniformly over an area.area.

–2. Examples of how pressure 2. Examples of how pressure affects humans & plants:affects humans & plants:a. a. Blood pressureBlood pressure in humans in humansb. b. Turgor pressureTurgor pressure in plants in plants

V. Fluid PressureV. Fluid Pressurea. Blood pressurea. Blood pressure

–1) Blood is moved throughout 1) Blood is moved throughout the human body through the the human body through the use of pressure.use of pressure.

–2) Blood pressure is the 2) Blood pressure is the pressure exerted by the blood pressure exerted by the blood on the walls of the blood on the walls of the blood vessels.vessels.

V. Fluid PressureV. Fluid Pressure– 3) The 3) The

continuous cycle continuous cycle of the heart of the heart contracting & contracting & relaxing creates relaxing creates the blood the blood pressure pressure measured in measured in millimeters of millimeters of mercury (mm mercury (mm Hg).Hg).

V. Fluid PressureV. Fluid Pressureb. Turgor pressureb. Turgor pressure

–1) Plants must take up water 1) Plants must take up water from the surrounding from the surrounding environment through the use of environment through the use of osmosis.osmosis.

–2) Once a plant cell is filled with 2) Once a plant cell is filled with water, its vacuoles become water, its vacuoles become swollen & large. The cell has a swollen & large. The cell has a large amount of fluid inside large amount of fluid inside causing a higher pressure.causing a higher pressure.

V. Fluid PressureV. Fluid Pressure– 3) The cell wall begins to exert 3) The cell wall begins to exert

pressure on the neighboring cell. pressure on the neighboring cell. The internal pressure inside the cell The internal pressure inside the cell is called turgor pressure. is called turgor pressure. See Figure See Figure 2.15 Turgor pressure from within the 2.15 Turgor pressure from within the cellcell

Complete Section Complete Section Review 2: The Cell Review 2: The Cell

Membrane & Cellular Membrane & Cellular TransportTransport

Complete ReviewComplete Review