The Living EnvironmentThe Living Environment

The study of organisms and The study of organisms and their interactions with the their interactions with the

environment.environment.

TopicsTopics

• Unit 1: EcologyUnit 1: Ecology

• Unit 2: The CellUnit 2: The Cell

• Unit 3: GeneticsUnit 3: Genetics

• Unit 4: History of Biological DiversityUnit 4: History of Biological Diversity

• Unit 5: The Human BodyUnit 5: The Human Body

Unit 2: The CellUnit 2: The Cell

Chemistry in BiologyChemistry in Biology Cellular Structure and FunctionCellular Structure and Function Cellular EnergyCellular Energy Cellular ReproductionCellular Reproduction

The Building Blocks of LifeThe Building Blocks of Life All organisms are made up of carbon-All organisms are made up of carbon-

based molecules. Specifically molecules based molecules. Specifically molecules called hydrocarbons. (...they contain C and called hydrocarbons. (...they contain C and H)H)

Macromolecules are large molecules that are Macromolecules are large molecules that are formed by joining smaller organic molecules formed by joining smaller organic molecules together. There are four major categories of together. There are four major categories of biological macromolecules:biological macromolecules:

CarbohydratesCarbohydrates: store energy and provide : store energy and provide structural support.structural support.

LipidsLipids: store energy and provide barriers: store energy and provide barriers ProteinsProteins: transport substances, speed reactions, : transport substances, speed reactions,

provide structural support, and make hormonesprovide structural support, and make hormones Nucleic AcidsNucleic Acids: store and communicate genetic : store and communicate genetic

informationinformation

CarbohydratesCarbohydrates

The diagram to the The diagram to the right is glucose right is glucose molecule.molecule.

Carbohydrates are Carbohydrates are compounds composed compounds composed of carbon, hydrogen, of carbon, hydrogen, and oxygen. CHand oxygen. CH22OO

Carbohydrates can be Carbohydrates can be simple sugars, simple sugars, monosaccharides, or monosaccharides, or complex sugars, complex sugars, polysaccharides.polysaccharides.

CarbohydratesCarbohydrates Glucose is a simple sugar or monosaccharide. Glucose is a simple sugar or monosaccharide.

Glucose plays a central role as an energy source for Glucose plays a central role as an energy source for organisms.organisms.

Sucrose, such as table sugar and lactose, is a Sucrose, such as table sugar and lactose, is a disaccharide. They also serve as an energy source disaccharide. They also serve as an energy source for organisms.for organisms.

Glycogen is a polysaccharide found as long chains of Glycogen is a polysaccharide found as long chains of glucose molecules in the liver and skeletal muscle to glucose molecules in the liver and skeletal muscle to be used as stored energy.be used as stored energy.

Cellulose is also a polysaccharide which is used to Cellulose is also a polysaccharide which is used to give structural support in the cell walls of plant cells.give structural support in the cell walls of plant cells.

Chitin is another polysaccharide and is the main Chitin is another polysaccharide and is the main component in the hard outer shell of shrimp, lobster, component in the hard outer shell of shrimp, lobster, and many insects.and many insects.

CarbohydratesCarbohydrates

LipidsLipids

The diagram to the The diagram to the right is a phospholipid.right is a phospholipid.

Lipids are composed of Lipids are composed of fatty acids, glycerol, fatty acids, glycerol, and other components.and other components.

Phospholipids act as Phospholipids act as barriers because of barriers because of their their hydrophilic,hydrophilic, “water-loving” heads “water-loving” heads and their and their hydrophobic,hydrophobic, “water-fearing” tails.“water-fearing” tails.

ProteinsProteins

Proteins are made of Proteins are made of small carbon compounds small carbon compounds called called amino acidsamino acids. There . There are 20 different amino are 20 different amino acids.acids.

There are four There are four conformations of conformations of proteins.proteins.

Cells contain about Cells contain about 10,000 different proteins 10,000 different proteins that transport substances that transport substances within the cell and within the cell and between cells, speed up between cells, speed up reactions, communicate reactions, communicate signals, and control cell signals, and control cell growth.growth.

Proteins as EnzymesProteins as Enzymes Catalysts are Catalysts are

substances which substances which increase the speed of increase the speed of a chemical reaction. a chemical reaction.

Enzymes are biological Enzymes are biological catalysts, composed of catalysts, composed of amino acids, that will amino acids, that will speed up the rate of speed up the rate of reactions such as reactions such as photosynthesis and photosynthesis and digestion.digestion.

Reactants of a Reactants of a chemical reaction are chemical reaction are called substrates.called substrates.

Proteins as EnzymesProteins as Enzymes When a substrate binds When a substrate binds

to the active site of an to the active site of an enzymatic protein a enzymatic protein a reaction occurs forming reaction occurs forming the products.the products.

Specific enzymes are Specific enzymes are designed to function designed to function only with specific only with specific substrates for specific substrates for specific reactions. The two fit reactions. The two fit like a lock and key.like a lock and key.

If a drug is introduced If a drug is introduced that chemically “fits” that chemically “fits” into the active site of into the active site of an enzyme, the an enzyme, the enzymatic reaction can enzymatic reaction can be blocked.be blocked.How Enzymes Work

Proteins as EnzymesProteins as Enzymes The effectiveness of The effectiveness of

an enzyme on the an enzyme on the rate of the reaction rate of the reaction can be affected by can be affected by factors such as pH factors such as pH and temperature.and temperature.

Enzymes are Enzymes are typically named typically named after the molecule after the molecule with which they will with which they will interact but end in –interact but end in –ase or –in. For ase or –in. For example, amylase, example, amylase, lipase, pepsin, and lipase, pepsin, and trypsin are all trypsin are all enzymes.enzymes.

Nucleic AcidsNucleic Acids

Nucleic acids are made Nucleic acids are made up of smaller repeating up of smaller repeating subunits called subunits called nucleotidesnucleotides..

There are six major There are six major nucleotides all of which nucleotides all of which contain a phosphate, contain a phosphate, nitrogenous base, and nitrogenous base, and a ribose sugar.a ribose sugar.

The main function of The main function of nucleic acids is to store nucleic acids is to store and transmit genetic and transmit genetic information such as information such as DNA and RNA.DNA and RNA.

Nucleic AcidsNucleic Acids

Adenosine Adenosine triphosphate triphosphate or ATP is a or ATP is a storehouse storehouse of chemical of chemical energy used energy used by cells.by cells.

Summary of MacromoleculesSummary of MacromoleculesCarbohydratCarbohydrateses

LipidsLipids ProteinsProteins Nucleic Nucleic AcidsAcids

Sugars/Sugars/starchesstarches

Fats/oils/ Fats/oils/ steroidssteroids

Amino acidsAmino acids NucleotidesNucleotides

Short termShort term

energy energy storagestorage

Provides Provides

structural structural

supportsupport

Long Long term term

energyenergy

storagestorage

Provides Provides aa

barrierbarrier

TransportsTransports

substancessubstancesEnzymesEnzymesStructuralStructural

supportsupportMake Make

hormoneshormonesCommunicatiCommunicationon

Store andStore and

communicatecommunicate

genetic infogenetic info

Storehouse Storehouse of of

chemical chemical

energyenergy

Describe what you see in the following Describe what you see in the following slide.slide.

Describe what you see in the following Describe what you see in the following slide.slide.

The CellThe Cell

First discovered in 1665 First discovered in 1665 by Robert Hooke who by Robert Hooke who built one of the first built one of the first light microscopes and light microscopes and viewed dead cork cells. viewed dead cork cells. He is credited for calling He is credited for calling them cellulae which them cellulae which eventually became the eventually became the word cell.word cell.

Not long after Hooke, Not long after Hooke, Anton van Anton van Leeuwenhoek designed Leeuwenhoek designed a microscope and a microscope and viewed living organisms viewed living organisms in pond water, milk, and in pond water, milk, and other substances.other substances.

The Cell TheoryThe Cell Theory

Developed in the mid 1800’s by German Developed in the mid 1800’s by German and Prussian scientists it states:and Prussian scientists it states:

1. All living organisms are composed of 1. All living organisms are composed of one or more cells.one or more cells.

2. Cells are the basic unit of structure and 2. Cells are the basic unit of structure and organization of all living things. “basic unit organization of all living things. “basic unit of life” – cells perform life functions.of life” – cells perform life functions.

3. Cells arise only from previously existing 3. Cells arise only from previously existing cells, with cells passing copies of their cells, with cells passing copies of their genetic material on to their daughter cells.genetic material on to their daughter cells.

The CellThe CellPlant cell using light microscopePlant cell using light microscope

The CellThe CellPlant cell using electron microscopePlant cell using electron microscope

Describe what you see in the following Describe what you see in the following slides.slides.

Types of CellsTypes of CellsProkaryote EukaryoteProkaryote Eukaryote

Visualizing Cells

The Plasma MembraneThe Plasma Membrane

The main function The main function of the plasma of the plasma membrane is to membrane is to maintain the cell’s maintain the cell’s homeostasis.homeostasis.

A cell’s homeostasis A cell’s homeostasis is controlled by the is controlled by the plasma membrane plasma membrane due to its due to its selective selective permeabilitypermeability..

The Plasma MembraneThe Plasma Membrane

The Fluid Mosaic Model

The Plasma MembraneThe Plasma Membrane Composed of a phospholipid bilayer, the Composed of a phospholipid bilayer, the

plasma membrane can maintain its structure plasma membrane can maintain its structure due to the polar heads and non-polar tails of due to the polar heads and non-polar tails of the lipids.the lipids.

Cholesterol molecules between the lipids Cholesterol molecules between the lipids keep them from sticking together and help keep them from sticking together and help the membrane maintain its fluidity.the membrane maintain its fluidity.

Carbohydrate chains identify the cell and help Carbohydrate chains identify the cell and help the cell identify incoming chemical signals.the cell identify incoming chemical signals.

The Phospholipid BilayerThe Phospholipid Bilayer

The Plasma MembraneThe Plasma Membrane

Transport ProteinsTransport Proteins: move needed substances or : move needed substances or waste materials through the plasma membrane.waste materials through the plasma membrane.

Receptor ProteinsReceptor Proteins: transmit signals to the inside : transmit signals to the inside of the cell.of the cell.

Support ProteinsSupport Proteins: anchor the plasma membrane : anchor the plasma membrane to the cytoskeleton and give the cell its shape.to the cytoskeleton and give the cell its shape.

The Plasma MembraneThe Plasma Membrane

The Fluid Mosaic ModelThe Fluid Mosaic Model The phospholipids can move sideways within the The phospholipids can move sideways within the

membrane as well as the proteins. This constant membrane as well as the proteins. This constant motion of molecules sliding past one another motion of molecules sliding past one another creates a fluidity of the membrane.creates a fluidity of the membrane.

Because there are different substances in the Because there are different substances in the membrane, a pattern, or mosaic, is created on its membrane, a pattern, or mosaic, is created on its surface.surface.

The CytoplasmThe Cytoplasm

Cytoplasm is the semi-Cytoplasm is the semi-fluid substance that fills fluid substance that fills the inside of all cells.the inside of all cells.

It is composed mostly It is composed mostly of water.of water.

In prokaryotes, In prokaryotes, chemical processes chemical processes occur directly in the occur directly in the cytoplasm. In cytoplasm. In eukaryotes these eukaryotes these processes occur in processes occur in organelles.organelles.

The CytoskeletonThe Cytoskeleton

The cytoskeleton is a The cytoskeleton is a supporting network of supporting network of long, thin protein long, thin protein fibers that form a fibers that form a framework for the cell.framework for the cell.

It is composed of It is composed of microtubules and microtubules and microfilaments that microfilaments that support the cell and support the cell and allow movement of allow movement of substances within the substances within the cell. cell.

Cell StructuresCell Structures

Cell StructuresCell Structures

The NucleusThe Nucleus

The nucleus is the cell’s The nucleus is the cell’s control center.control center.

It contains most of the It contains most of the cell’s DNA which is used to cell’s DNA which is used to make proteins for cell make proteins for cell growth, function, and growth, function, and reproduction.reproduction.

The nucleus is surrounded The nucleus is surrounded by a double membrane by a double membrane called the nuclear called the nuclear envelope. It has pores to envelope. It has pores to allow substances to move allow substances to move in and out of the nucleus.in and out of the nucleus.

The Nucleus continued…The Nucleus continued…

Within the nucleus is Within the nucleus is the site of ribosome the site of ribosome production called the production called the nucleolus.nucleolus.

As ribosomes are As ribosomes are produced they move produced they move out of the nucleus and out of the nucleus and either attach to either attach to endoplasmic reticulum endoplasmic reticulum or are free floating in or are free floating in the cytoplasm.the cytoplasm.

The RibosomeThe Ribosome

RibosomesRibosomes Ribosomes are composed of RNA and Ribosomes are composed of RNA and

protein, and are NOT membrane bound protein, and are NOT membrane bound organelles.organelles.

The function of ribosomes is to synthesize The function of ribosomes is to synthesize

PROTEINS!PROTEINS!

Endoplasmic ReticulumEndoplasmic Reticulum ER is composed of ER is composed of

folded membrane and folded membrane and sacs and is a site for sacs and is a site for protein and lipid protein and lipid synthesis.synthesis.

Rough ER is covered by Rough ER is covered by ribosomes that produce ribosomes that produce proteins.proteins.

Smooth ER lacks Smooth ER lacks ribosomes and is a site ribosomes and is a site for polysaccharide and for polysaccharide and phospholipid synthesis.phospholipid synthesis.

Golgi ApparatusGolgi Apparatus Golgi Apparatus, or Golgi Apparatus, or

Golgi Body, is a Golgi Body, is a flattened stack of flattened stack of folded membranes.folded membranes.

Its function is to Its function is to modify, sort, and modify, sort, and package proteins into package proteins into sacs called vesicles.sacs called vesicles.

These vesicles can These vesicles can then be shipped then be shipped outside of the cell.outside of the cell.

Sometimes referred to Sometimes referred to as the cell’s post office.as the cell’s post office.

VacuolesVacuoles

A membrane bound A membrane bound sac used to sac used to temporarily store temporarily store food, water, food, water, enzymes, and enzymes, and sometimes waste.sometimes waste.

Plant cells require Plant cells require very large central very large central vacuoles for storing vacuoles for storing water.water.

MitochondriaMitochondria

Mitochondria have an Mitochondria have an outer membrane and a outer membrane and a folded inner membrane folded inner membrane that forms many that forms many cristae.cristae.

Cristae provide a large Cristae provide a large surface area for surface area for breaking down sugar breaking down sugar molecules.molecules.

Mitochondria are known Mitochondria are known as the “powerhouse” of as the “powerhouse” of the cell.the cell.

MitochondriaMitochondria Mitochondria are found in Mitochondria are found in

all eukaryotes and are all eukaryotes and are responsible for responsible for cellular cellular respirationrespiration..

Mitochondria release the Mitochondria release the energy from nutrients energy from nutrients obtained by the cell.obtained by the cell.

They have their own DNA They have their own DNA called mDNA. Because of called mDNA. Because of this fact, they are believed this fact, they are believed to have once been single to have once been single celled organisms celled organisms themselves.themselves.

ChloroplastsChloroplasts

Chloroplasts are found Chloroplasts are found only in photosynthetic only in photosynthetic cells such as plant cells.cells such as plant cells.

They have an outer and They have an outer and inner lipid membrane inner lipid membrane and contain stacks of and contain stacks of thylakoids.thylakoids.

In many ways they are In many ways they are similar to mitochondria similar to mitochondria but DO NOT perform but DO NOT perform the same function.the same function.

ChloroplastsChloroplasts Chloroplasts are Chloroplasts are

responsible for using responsible for using sunlight to produce sunlight to produce chemical energy through chemical energy through a process called a process called photosynthesisphotosynthesis..

Chloroplasts contain a Chloroplasts contain a green pigment that traps green pigment that traps sunlight called chlorophyll.sunlight called chlorophyll.

They also have their own They also have their own DNA and are believed to DNA and are believed to have once been a single have once been a single celled organism known as celled organism known as cyanobacteria, possibly cyanobacteria, possibly the first life forms on the first life forms on Earth.Earth.

LysosomesLysosomes

Lysosomes are Lysosomes are membrane bound membrane bound vesicles that digest vesicles that digest excess or worn out excess or worn out organelles and food organelles and food particles.particles.

They will also digest They will also digest bacteria and viruses bacteria and viruses that have entered the that have entered the cell.cell.

Lysosomes function to Lysosomes function to keep the inside of the keep the inside of the cell clean.cell clean.

CentriolesCentrioles

Centrioles are groups Centrioles are groups of microtubules that of microtubules that function during cell function during cell division.division.

They produce the They produce the spindle fibers that spindle fibers that separate separate chromosomes during chromosomes during mitosis and meiosis.mitosis and meiosis.

Usually found in pairs Usually found in pairs called centrosome.called centrosome.

Cell WallCell Wall

The cell wall is a thick, The cell wall is a thick, rigid, mesh composed rigid, mesh composed of cellulose and of cellulose and structural proteins.structural proteins.

It surrounds the cell It surrounds the cell membrane of plant membrane of plant cells and provides cells and provides protection and protection and structural support for structural support for the cell.the cell.

Cilia and FlagellaCilia and Flagella

Cilia and flagella are Cilia and flagella are both composed of both composed of microtubules.microtubules.

They are used for They are used for locomotion and/or locomotion and/or feeding in different feeding in different types of cells.types of cells.

Cilia are usually very Cilia are usually very numerous although numerous although there are typically there are typically only one or two only one or two flagella if they are flagella if they are present.present.

Not all cells have cilia Not all cells have cilia or flagella. or flagella.

Cellular TransportCellular Transport

Cellular Transport moves substances Cellular Transport moves substances within the cell and moves substances within the cell and moves substances into and out of the cell.into and out of the cell.

Cellular Transport is primarily carried Cellular Transport is primarily carried out by the plasma membrane and out by the plasma membrane and the cytoskeleton, specifically the the cytoskeleton, specifically the cell’s microtubules.cell’s microtubules.

Passive Transport:Passive Transport: Diffusion Diffusion Diffusion is the Diffusion is the

net movement net movement of particles of particles down the down the concentration concentration gradient.gradient.

Particles Particles always move always move from an area from an area of high of high concentration concentration to an area of to an area of low low concentration concentration until an until an equilibrium equilibrium has been has been reached.reached.

Diffusion...continued

• Once the concentrations are equal, particles will continue to move randomly but will maintain a dynamic equilibrium.

• Factors affecting the rate of diffusion are concentration, temperature, and pressure.

Diffusion across the plasma Diffusion across the plasma membranemembrane

Facilitated diffusion uses transport proteins Facilitated diffusion uses transport proteins to move ions and small molecules across to move ions and small molecules across the plasma membrane. the plasma membrane.

Figure (a) is a channel protein and figure Figure (a) is a channel protein and figure (b) is a carrier protein.(b) is a carrier protein.

Osmosis...Osmosis... ...the diffusion of water across a selectively ...the diffusion of water across a selectively

permeable membrane.permeable membrane. Regulating the movement of water across Regulating the movement of water across

the plasma membrane is an important factor the plasma membrane is an important factor in maintaining in maintaining homeostasishomeostasis within the cell. within the cell.

Cells in solution...Cells in solution... When a cell is in an When a cell is in an isotonicisotonic solution, the solution, the

concentration of water and solutes outside concentration of water and solutes outside the cell is equal to the concentration inside the cell is equal to the concentration inside the cell...effectively creating a dynamic the cell...effectively creating a dynamic equilibrium.equilibrium.

When a cell is in a When a cell is in a hypotonichypotonic solution, the solution, the concentration of water is greater outside the concentration of water is greater outside the cell than inside...causing water to rush into cell than inside...causing water to rush into the cell and causing it to swell and possibly the cell and causing it to swell and possibly burst. (cellular lysing)burst. (cellular lysing)

When a cell is in a When a cell is in a hypertonichypertonic solution, the solution, the concentration of water is greater inside the concentration of water is greater inside the cell than outside...causing water to rush out cell than outside...causing water to rush out of the cell, resulting in the cell shriveling.of the cell, resulting in the cell shriveling.

Cells in solution...Cells in solution...

Osmosis in Various Solutions

Passive Transport vs. Active Passive Transport vs. Active TransportTransport

Passive transportPassive transport, such as diffusion , such as diffusion and osmosis, does not require the use and osmosis, does not require the use of any energy to move the substance of any energy to move the substance because substances naturally flow because substances naturally flow withwith the concentration gradient. the concentration gradient.

Active transportActive transport is necessary when is necessary when substances must move substances must move againstagainst the the concentration gradient, that is, from concentration gradient, that is, from areas of low concentration to areas of areas of low concentration to areas of higher concentration.higher concentration. Therefore, active transport typically Therefore, active transport typically

requires the use of an energy source, requires the use of an energy source, usually ATP.usually ATP.

Passive Transport vs. Active Passive Transport vs. Active TransportTransport

Figure (a) is a channel protein used for Figure (a) is a channel protein used for passive transport because it does not require passive transport because it does not require the use of energy to change its conformation.the use of energy to change its conformation.

Figure (b) is a carrier protein used for active Figure (b) is a carrier protein used for active transport which does require the use of transport which does require the use of energy because the protein must change its energy because the protein must change its conformation.conformation.

Passive TransportPassive Transport

Active TransportActive Transport In order to maintain homeostasis, cells often In order to maintain homeostasis, cells often

need to remove substances or absorb need to remove substances or absorb substances against their concentration substances against their concentration gradients.gradients.

Moving substances from lower Moving substances from lower concentrations to higher concentrations concentrations to higher concentrations across the plasma membrane requires across the plasma membrane requires energy.energy.

Active transport occurs with the aid of Active transport occurs with the aid of carrier proteins, sometimes called pumps.carrier proteins, sometimes called pumps.

Active TransportActive Transport

Sodium/Potassium ATPase PumpSodium/Potassium ATPase Pump

The pump uses energy The pump uses energy in the form of ATP to in the form of ATP to transport sodium out transport sodium out of the cell, while of the cell, while moving potassium into moving potassium into the cell.the cell.

This pump moves ions This pump moves ions against their against their concentration gradient concentration gradient and is therefore an and is therefore an example of active example of active transport.transport.

Sodium Potassium Sodium Potassium Pump Pump

Transport of Large ParticlesTransport of Large Particles

EndocytosisEndocytosis is the is the process by which a cell process by which a cell surrounds a substance surrounds a substance in the outside in the outside environment, enclosing environment, enclosing the substance in a the substance in a portion of the plasma portion of the plasma membrane. membrane.

The membrane then The membrane then pinches off, creating a pinches off, creating a vacuole containing the vacuole containing the substance within the substance within the cell.cell.

ExocytosisExocytosis is the is the secretion of materials secretion of materials at the plasma at the plasma membrane. membrane.

Cells use exocytosis to Cells use exocytosis to expel waste and expel waste and secrete substances secrete substances with the use of with the use of vesicles produced by vesicles produced by the Golgi apparatus.the Golgi apparatus.

Endocytosis and Endocytosis and ExocytosisExocytosis

Cellular EnergyCellular Energy

All of the chemical reactions that take All of the chemical reactions that take place within a cell are referred to as the place within a cell are referred to as the cell’s cell’s metabolismmetabolism..

A common A common exampleexample of metabolism that of metabolism that takes place within your body is the takes place within your body is the body’s ability to breakdown food into body’s ability to breakdown food into nutrients and utilize the carbohydrates nutrients and utilize the carbohydrates and fats as a source of energy.and fats as a source of energy.

Cellular EnergyCellular Energy PhotosynthesisPhotosynthesis and and Cellular Cellular

RespirationRespiration are examples of are examples of metabolic pathways, whereby metabolic pathways, whereby chemical reactions take place that chemical reactions take place that result in energy transfer.result in energy transfer.

Photosynthesis occurring in Photosynthesis occurring in autotrophs and Cellular Respiration autotrophs and Cellular Respiration occurring in heterotrophs, results in a occurring in heterotrophs, results in a natural cycle known as the Carbon-natural cycle known as the Carbon-dioxide/Oxygen cycle.dioxide/Oxygen cycle.

ATP: The Unit of Cellular ATP: The Unit of Cellular EnergyEnergy

Adenosine Tri-Adenosine Tri-Phosphate is a Phosphate is a biological molecule that biological molecule that provides chemical provides chemical energy.energy.

ATP is composed of an ATP is composed of an adenine base, ribose adenine base, ribose sugar, and three sugar, and three phosphate groups.phosphate groups.

ATP releases energy ATP releases energy when the bond between when the bond between the second and third the second and third phosphate groups is phosphate groups is broken; producing ADP broken; producing ADP + Energy+ Energy

PHOTOSYNTHESISPHOTOSYNTHESIS

Photosynthesis Photosynthesis occurs in all occurs in all autotrophic autotrophic organisms including organisms including plants, algae, and plants, algae, and some bacteria.some bacteria.

Photosynthesis is the Photosynthesis is the chemical process of chemical process of using carbon-dioxide using carbon-dioxide and water, in the and water, in the presence of sunlight, presence of sunlight, to produce glucose to produce glucose and oxygen.and oxygen.

PHOTOSYNTHESISPHOTOSYNTHESIS Photosynthesis Photosynthesis

occurs inside occurs inside organelles called organelles called chloroplasts, which chloroplasts, which contain a green contain a green pigment called pigment called chlorophyll.chlorophyll.

Other photosynthetic Other photosynthetic pigments, such as pigments, such as ß-ß-carotene, result in carotene, result in other colors such as other colors such as the orange-yellow the orange-yellow color of carrots and color of carrots and sweet potatoes.sweet potatoes.

PHOTOSYNTHESISPHOTOSYNTHESIS Photosynthesis typically occurs in two Photosynthesis typically occurs in two

phases:phases:

Phase I: Phase I: Light ReactionsLight Reactions – light is – light is captured and the energy is temporarily captured and the energy is temporarily stored as NADPH and ATP.stored as NADPH and ATP.

Phase II: Phase II: The Calvin CycleThe Calvin Cycle – NADPH and – NADPH and ATP produced from the light reactions ATP produced from the light reactions are converted to and stored as glucose.are converted to and stored as glucose.

PHOTOSYNTHESIS ReactionPHOTOSYNTHESIS Reaction

6CO6CO22 + + 6H6H22O O sunlightsunlight CC66HH1212OO66 + + 6O6O22

Carbon-dioxide + Water Carbon-dioxide + Water sunlightsunlight Glucose + Glucose + OxygenOxygen

PhotosynthesisPhotosynthesis

Cellular RespirationCellular Respiration Cellular respiration Cellular respiration

occurs in both occurs in both autotrophs and autotrophs and heterotrophs.heterotrophs.

Cellular respiration Cellular respiration is the chemical is the chemical process of process of releasing energy releasing energy from glucose and from glucose and using that energy using that energy to make ATP.to make ATP.

Cellular RespirationCellular Respiration

Cellular respiration Cellular respiration occurs within occurs within organelles called organelles called mitochondria, found mitochondria, found in all Eukaryotes.in all Eukaryotes.

Similar to Similar to photosynthesis, photosynthesis, cellular respiration cellular respiration occurs in two occurs in two stages.stages.

Cellular RespirationCellular Respiration

The first stage of cellular respiration The first stage of cellular respiration is called glycolysis which is an is called glycolysis which is an anaerobic process, and therefore anaerobic process, and therefore does not require oxygen.does not require oxygen.

The second stage of cellular The second stage of cellular respiration is an aerobic process and respiration is an aerobic process and includes the Krebs cycle. This stage includes the Krebs cycle. This stage does require the use of oxygen.does require the use of oxygen.

Cellular Respiration Cellular Respiration ReactionReaction

CC66HH1212OO66 + + 6O6O22 6CO 6CO22 + + 6H6H22O O + +

ATPATP

Glucose + Oxygen Carbon-dioxide + Water + Glucose + Oxygen Carbon-dioxide + Water + ENERGYENERGY

Photosynthesis Photosynthesis & & Cellular Cellular RespirationRespiration

Reactions ComparedReactions Compared Photosynthesis ReactionPhotosynthesis Reaction

6CO6CO22 + + 6H6H22O O sunlightsunlight CC66HH1212OO66 + + 6O6O22

Cellular Respiration Cellular Respiration ReactionReaction

CC66HH1212OO66 + + 6O6O22 6CO 6CO22 + + 6H6H22O O + +

ATPATP

The Cell Cycle / Cellular The Cell Cycle / Cellular ReproductionReproduction

The Cell Cycle is The Cell Cycle is essentially the life essentially the life cycle of a cell.cycle of a cell.

The Cell Cycle The Cell Cycle includes three phases: includes three phases: Interphase, Mitosis, Interphase, Mitosis, and Cytokinesis.and Cytokinesis.

Interphase is divided Interphase is divided into 3 subphases: G1, into 3 subphases: G1, S, and G2.S, and G2.

The Cell CycleThe Cell Cycle

The Cell CycleThe Cell Cycle

Interphase is the first Interphase is the first and longest phase of the and longest phase of the cell cycle.cell cycle.

During G1 (Gap1), the During G1 (Gap1), the cell grows and performs cell grows and performs normal functions.normal functions.

During S (synthesis), During S (synthesis), DNA in the nucleus is DNA in the nucleus is replicated.replicated.

During G2 (Gap2), the During G2 (Gap2), the cell prepares for Mitosis.cell prepares for Mitosis.

During Interphase S...During Interphase S... DNA in the nucleus DNA in the nucleus

replicates itself forming replicates itself forming sister chromatids.sister chromatids.

Pairs of identical sister Pairs of identical sister chromatids are chromatids are connected at the center connected at the center with a centromere with a centromere forming an X shaped forming an X shaped chromosome during chromosome during prophase of mitosis.prophase of mitosis.

MitosisMitosis

Mitosis is the stage of Mitosis is the stage of the cell cycle during the cell cycle during which the cell’s which the cell’s nucleus and nuclear nucleus and nuclear material divide.material divide.

Mitosis occurs in four Mitosis occurs in four substages: Prophase, substages: Prophase, Metaphase, Metaphase, Anaphase, and Anaphase, and Telophase.Telophase.

ProphaseProphase

During Prophase...During Prophase...

Nuclear envelope disintegrates.Nuclear envelope disintegrates. Nucleolus disappears.Nucleolus disappears. Chromatin (DNA strand) condenses Chromatin (DNA strand) condenses

forming X-shaped chromosomes of forming X-shaped chromosomes of identical pairs of sister chromatids.identical pairs of sister chromatids.

Centrioles move toward opposite Centrioles move toward opposite sides of the cell and produce the sides of the cell and produce the mitotic spindle fibers.mitotic spindle fibers.

MetaphaseMetaphase

During Metaphase...During Metaphase...

Chromosomes align along the cell’s Chromosomes align along the cell’s equator forming the metaphase equator forming the metaphase plate.plate.

Spindle fibers attach to each Spindle fibers attach to each chromosome at the centromere.chromosome at the centromere.

AnaphaseAnaphase

During Anaphase...During Anaphase...

Sister chromatids are pulled apart at Sister chromatids are pulled apart at the centromeres as the spindle fibers the centromeres as the spindle fibers contract.contract.

Chromosomes move toward opposite Chromosomes move toward opposite poles of the cell.poles of the cell.

TelophaseTelophase

During Telophase...During Telophase...

Chromosomes reach opposite poles Chromosomes reach opposite poles of the cell.of the cell.

Mitotic spindle fibers disappear.Mitotic spindle fibers disappear. Nuclear envelope reforms.Nuclear envelope reforms. Nucleolus reappears.Nucleolus reappears. Chromosomes decondense back into Chromosomes decondense back into

Chromatin (DNA strand).Chromatin (DNA strand).

CytokinesisCytokinesis In animal cells: microfilaments pinch inward at the In animal cells: microfilaments pinch inward at the

cell’s equator until the cell divides in two.cell’s equator until the cell divides in two. In plant cells: a cell plate forms where the metaphase In plant cells: a cell plate forms where the metaphase

plate had formed earlier and then a new cell wall plate had formed earlier and then a new cell wall forms on either side, dividing the cell in two.forms on either side, dividing the cell in two.

MitosisMitosis

Mitosis continued...Mitosis continued...

Various Stages of Mitosis Various Stages of Mitosis Occurring in an Onion Root TipOccurring in an Onion Root Tip

Results of MitosisResults of Mitosis Essentially, Mitosis is a Essentially, Mitosis is a

form of asexual cell form of asexual cell reproduction.reproduction.

A single parent cell A single parent cell makes a copy of its makes a copy of its genetic information, genetic information, then splits into two new then splits into two new cells called daughter cells called daughter cells.cells.

Daughter cells formed Daughter cells formed as a result of mitosis are as a result of mitosis are identicalidentical to each other to each other and to the parent cell.and to the parent cell.The Cell Cycle & MitosisThe Cell Cycle & Mitosis

What are the roles of What are the roles of Mitosis?Mitosis?

Growth and DevelopmentGrowth and Development

Replacement of damaged/dead cellsReplacement of damaged/dead cells

Abnormal Cell Cycle: Abnormal Cell Cycle: CancerCancer

Cancer is the Cancer is the uncontrolled growth uncontrolled growth and division of cells.and division of cells.

Cancer is typically Cancer is typically the result of a change the result of a change in the DNA that in the DNA that controls the controls the production of production of proteins that regulate proteins that regulate the cell cycle.the cell cycle.

Substances known to Substances known to cause cancer are cause cancer are called carcinogens.called carcinogens.

Apoptosis: Programmed Cell Apoptosis: Programmed Cell DeathDeath

Apoptosis occurs to Apoptosis occurs to normal cells when they normal cells when they receive the signal, receive the signal, usually in the form of usually in the form of genetic code, to commit genetic code, to commit suicide.suicide.

The cell will shrink, the The cell will shrink, the nucleus will collapse, nucleus will collapse, and the cell and all and the cell and all organelles will lyse.organelles will lyse.

Apoptosis typically Apoptosis typically occurs in developing occurs in developing fetuses as well as in fetuses as well as in cells with damaged DNA.cells with damaged DNA.

Stem cellsStem cells Stem cells are unspecialized cells that can Stem cells are unspecialized cells that can

develop into specialized cells under the right develop into specialized cells under the right conditions.conditions.

Stem cells have the potential to replace any Stem cells have the potential to replace any damaged cell(s) anywhere in the body.damaged cell(s) anywhere in the body.

MeiosisMeiosis Meiosis is a specialized Meiosis is a specialized

type of cell division that type of cell division that results in the production of results in the production of gametes, or sex cells.gametes, or sex cells.

Meiosis only occurs within Meiosis only occurs within the reproductive organs of the reproductive organs of organisms that reproduce organisms that reproduce sexually.sexually.

Because the cells Because the cells produced by meiosis are produced by meiosis are only used for only used for reproduction, they contain reproduction, they contain ½ the number of ½ the number of chromosomes as the chromosomes as the original cell.original cell.

MeiosisMeiosis

In order to maintain the In order to maintain the same number of same number of chromosomes from parent chromosomes from parent to offspring, sex cells can to offspring, sex cells can only have ½ the number only have ½ the number of chromosomes as typical of chromosomes as typical body cells.body cells.

For example: Human body For example: Human body cells (somatic cells) each cells (somatic cells) each contain 46 chromosomes, contain 46 chromosomes, but human gametes (sex but human gametes (sex cells) only contain 23 cells) only contain 23 chromosomes in each cell.chromosomes in each cell.

How Meiosis WorksHow Meiosis Works

MeiosisMeiosis Meiosis involves two Meiosis involves two

consecutive cell consecutive cell divisions called meiosis I divisions called meiosis I and meiosis II.and meiosis II.

By the end of meiosis I, By the end of meiosis I, two new cells are two new cells are produced each produced each containing the same containing the same number of chromosomes number of chromosomes as the parent cell, but as the parent cell, but with genetic variation.with genetic variation.

By the end of meiosis II, By the end of meiosis II, four cells have been four cells have been produced, each produced, each containing ½ the containing ½ the number of chromosomes number of chromosomes as the original cell, each as the original cell, each with genetic variation.with genetic variation.Stages of MeiosisStages of Meiosis

MeiosisMeiosis During prophase of During prophase of

meiosis I, homologous meiosis I, homologous chromosomes pair chromosomes pair together forming a together forming a tetrad.tetrad.

Once paired, crossing Once paired, crossing over occurs, resulting in over occurs, resulting in recombinant recombinant chromosomes that chromosomes that allows genetic variation allows genetic variation among offspring of the among offspring of the same parents.same parents.

In males, each of the In males, each of the four daughter cells will four daughter cells will become a sperm cell. become a sperm cell. In females, only one In females, only one daughter cell will daughter cell will survive to become an survive to become an egg cell.egg cell. Unique Features of Unique Features of

MeiosisMeiosis

Comparison of Meiosis and Comparison of Meiosis and MitosisMitosis