Life ScienceLife Science

Cells: Cells: The Building Blocks of The Building Blocks of

LifeLife

Section 1 – What is Life?Section 1 – What is Life?Six Characteristics of Living Six Characteristics of Living

OrganismsOrganisms 1. 1. CellularCellular OrganizationOrganization 2. 2. ChemicalsChemicals of Life ( of Life (OrganizationOrganization)) 3. 3. Energy UsedEnergy Used 4. 4. GrowthGrowth and and DevelopmentDevelopment 5. 5. ResponseResponse to Stimuli to Stimuli 6. 6. ReproductionReproduction

1. Cellular Organization 1. Cellular Organization

a. a. CellCell – basic unit of structure – basic unit of structure b. b. UnicellularUnicellular – one celled organism – one celled organism c. c. MulticellularMulticellular – many celled – many celled

organismorganism

2. Chemicals of Life 2. Chemicals of Life ((OrganizationOrganization))

a. a. WaterWater most abundant in cells most abundant in cells b. b. CarbohydratesCarbohydrates (energy) (energy) c. c. ProteinsProteins and and lipidslipids (building (building

materials)materials) d. d. NucleicNucleic acidsacids (genetic material – (genetic material –

information)information) DNA and RNADNA and RNA The computer coding (programs) for the The computer coding (programs) for the

forming and function of living things.forming and function of living things.

3. Energy Used3. Energy Used – to function (to move, to grow, – to function (to move, to grow, etc.)etc.)

4. Growth and Development4. Growth and Development GrowthGrowth = getting bigger = getting bigger DevelopmentDevelopment = becoming more mature or = becoming more mature or

complexcomplex

5. Response5. Response to Stimuli in the Surroundings to Stimuli in the Surroundings ((HomeostasisHomeostasis)) SStimulustimulus = what causes the organism to = what causes the organism to

respond.respond.

6. Reproduction6. Reproduction = produce offspring = produce offspring

Errors in logicErrors in logic

Misleading

Misleading information

information

False informationFalse information

Pure BaloneyPure Baloney

Selective use of evidenceSelective use of evidence

Tuning Up Our Phony Tuning Up Our Phony Baloney DetectorBaloney DetectorLet’s go baloney huntingLet’s go baloney hunting

A False Idea: A False Idea: Spontaneous GenerationSpontaneous Generation

Scientists once believed that rotten Scientists once believed that rotten meat turned into fly larvae and old meat turned into fly larvae and old rags turned into mice.rags turned into mice.

They believed living things They believed living things spontaneously generated from these spontaneously generated from these non-living things.non-living things.

But, controlled experiments showed But, controlled experiments showed that this “scientific” belief that this “scientific” belief (hypothesis) was wrong.(hypothesis) was wrong.

Life Comes From Life, NEVER from spontaneous generation._______________A man named Redi experimented with meat, to show that fly larvae only come from fly eggs, not meat.

Life Comes From Life, NEVER from non-living matter._______________A man named Pasteur did an experiment with flasks to show that bacteria do not come from liquid broth.

The Four Needs of Living The Four Needs of Living Things: Things: (Energy, Water, Space, (Energy, Water, Space,

Homeostasis)Homeostasis) 1. 1. EnergyEnergy (need food to function) Two kinds of (need food to function) Two kinds of

feeders –feeders – a. a. AutotrophsAutotrophs = make their own food = make their own food (plants are (plants are

autotrophs)autotrophs) b. b. HeterotrophsHeterotrophs = cannot make their own food = cannot make their own food

(animals)(animals) (People, dogs, lizards, are heterotrophs).(People, dogs, lizards, are heterotrophs). 2. 2. WaterWater – all living things need water to survive. – all living things need water to survive. 3. 3. LivingLiving SpaceSpace – need a place to get food, water, and – need a place to get food, water, and

shelter.shelter. 4. 4. HomeostasisHomeostasis = = StableStable Internal Conditions – so Internal Conditions – so

when the temperature gets too cold or hot, or too wet when the temperature gets too cold or hot, or too wet or dry where they live, their body still stays the same or dry where they live, their body still stays the same inside. inside.

Section 2: Discovering CellsSection 2: Discovering Cells MicroscopeMicroscope = makes small objects appear = makes small objects appear

larger.larger. The first cell sightings were possible because The first cell sightings were possible because

of the invention of the microscope.of the invention of the microscope. * An * An ElectronElectron Microscope = Microscope = does not use does not use

light, but uses a beam of electrons instead.light, but uses a beam of electrons instead. LightLight Microscope: Microscope:

- - ConvexConvex lens = a lens with a curved shape lens = a lens with a curved shape - - MagnificationMagnification = how large image appears = how large image appears

under the scope.under the scope. - - ResolutionResolution = is how clear or sharp the = is how clear or sharp the

image is.image is. CompoundCompound LightLight MicroscopeMicroscope = a light = a light

microscope with more than one lens.microscope with more than one lens.

Men Behind the Men Behind the MicroscopeMicroscope

HookeHooke = first person to observe cells = first person to observe cells (cork cells from cork wood).(cork cells from cork wood).

LeeuwenhoekLeeuwenhoek = first to see tiny one- = first to see tiny one-celled organisms in water drops.celled organisms in water drops.

SchleidenSchleiden = the first scientist to = the first scientist to conclude that all plants are composed of conclude that all plants are composed of cells.cells.

SchwannSchwann = the first scientist to conclude = the first scientist to conclude that all animals are composed of cells.that all animals are composed of cells.

Hooke’s Hooke’s MicroscopeMicroscope

Cell TheoryCell Theory CellCell TheoryTheory = based on the = based on the

discoveries of these men, and it discoveries of these men, and it states that:states that:1. All living things are 1. All living things are composedcomposed of of

cells.cells.2. Cells are the 2. Cells are the basic unitbasic unit of structure of structure

and function in living things.and function in living things.3. All cells are 3. All cells are producedproduced by other cells. by other cells.

Section 3: Looking Inside Section 3: Looking Inside CellsCells

Cell WallCell Wall = a tough, rigid layer = a tough, rigid layer surrounding the outside of surrounding the outside of plantplant cells, cells, NOT animal cells.NOT animal cells.

Cell MembraneCell Membrane = The next layer, just = The next layer, just inside the cell wall.inside the cell wall. * * AnimalAnimal cells ONLY have a membrane cells ONLY have a membrane

layer, and do not have a cell wall.layer, and do not have a cell wall.The cell membrane controls what The cell membrane controls what substances come into and go out of a cell.substances come into and go out of a cell.

It is the It is the gatekeepergatekeeper of the cell. of the cell.

The Center of the CellThe Center of the Cell

NucleusNucleus = the “brain” or code computer = the “brain” or code computer control center of the cell. control center of the cell. - It is a large oval structure inside the cell.- It is a large oval structure inside the cell.

NuclearNuclear MembraneMembrane = surrounds the oval = surrounds the oval nucleus.nucleus.

ChromatinChromatin = strands of genetic material = strands of genetic material (genes) floating inside the nucleus. They contain (genes) floating inside the nucleus. They contain the coded information which tells the cell how to the coded information which tells the cell how to function.function.

NucleolusNucleolus = a small object where ribosomes = a small object where ribosomes are made.are made.

CytoplasmCytoplasm

CytoplasmCytoplasm = the region inside the cell = the region inside the cell between the cell membrane and the between the cell membrane and the nucleus.nucleus. - It contains a jelly like fluid, with many - It contains a jelly like fluid, with many

organelles floating in it.organelles floating in it. OrganellesOrganelles in the Cytoplasm in the Cytoplasm = tiny cell = tiny cell

structures that carry out functions in the structures that carry out functions in the cell.cell. They function to produce energy, build and They function to produce energy, build and

transport materials, and store or recycle transport materials, and store or recycle wastes.wastes.

MitochondriaMitochondria = rod shaped = rod shaped “powerhouse” organelles in the “powerhouse” organelles in the cytoplasm.cytoplasm. These produce most of the energy the These produce most of the energy the

cells needs.cells needs.

EndoplasmicEndoplasmic ReticulumReticulum = (ER) a = (ER) a twisted maze of passageways that twisted maze of passageways that carry proteins and other materials carry proteins and other materials from one area of the cell to another.from one area of the cell to another.

RibosomesRibosomes = tiny grain-like bodies. = tiny grain-like bodies. Some are attached to the surface of the Some are attached to the surface of the

endoplasmic reticulum.endoplasmic reticulum. Others float in the cytoplasm.Others float in the cytoplasm. Ribosomes are factories that make proteins.Ribosomes are factories that make proteins. The proteins are then transported to the The proteins are then transported to the

Golgi Bodies.Golgi Bodies.

Golgi BodiesGolgi Bodies = look like flat collections = look like flat collections of sacs, that function as the mail room.of sacs, that function as the mail room. They receive the proteins and other newly They receive the proteins and other newly

formed materials from the, ER, package formed materials from the, ER, package them, and distribute them around the cell, them, and distribute them around the cell, and release them outside the cell.and release them outside the cell.

ChloroplastsChloroplasts = large green structures in = large green structures in plant cells, but NOT animal cells.plant cells, but NOT animal cells. They capture energy from sunlight and use it They capture energy from sunlight and use it

to produce food for a cell.to produce food for a cell. They contain a green coloring (a pigment) They contain a green coloring (a pigment)

called chlorophyll.called chlorophyll. VacuolesVacuoles = storage areas in cells, for = storage areas in cells, for

water, food, and waste.water, food, and waste. Plants cells usually have one large vacuole.Plants cells usually have one large vacuole. Animals cells have many smaller ones.Animals cells have many smaller ones.

LysosomesLysosomes = round structures containing = round structures containing chemicals to break down food for use.chemicals to break down food for use. They also break down old cell parts, for reuse They also break down old cell parts, for reuse

again.again. They are the cleanup crew of the cell.They are the cleanup crew of the cell.

Bacterial CellsBacterial Cells = very different from = very different from plant and animal cells.plant and animal cells. Usually smaller than plant and animal cells.Usually smaller than plant and animal cells. 10 times smaller than a human skin cell 10 times smaller than a human skin cell Have no nucleus, so they are called Have no nucleus, so they are called

prokaryotes. prokaryotes. ProkaryotesProkaryotes have genetic material like have genetic material like

a tangled string in the cytoplasm.a tangled string in the cytoplasm. Prokaryotes have a cell wall and cell Prokaryotes have a cell wall and cell

membrane.membrane. EukaryotesEukaryotes (plants and animals) have (plants and animals) have

a nucleus, and many organelles.a nucleus, and many organelles.

Specialized cellsSpecialized cells = = In multicellular organisms like In multicellular organisms like

humans and dogs, there are humans and dogs, there are many different kinds of cells, many different kinds of cells, with different sizes, shapes, and with different sizes, shapes, and functions.functions.

Skin cells, muscle cells, nerve Skin cells, muscle cells, nerve cells, bone cells, blood cells, cells, bone cells, blood cells, etc.etc.

Section 4: Origin of Life: Section 4: Origin of Life: 1. 1. EvolutionEvolution – The text book tries to – The text book tries to

present this view. present this view. It says that life arose from non-life. That It says that life arose from non-life. That

would require spontaneous generation, would require spontaneous generation, which has been shown by Redi, Pasteur, which has been shown by Redi, Pasteur, and others to be a false belief.and others to be a false belief.

It mentions the experiments by Miller and It mentions the experiments by Miller and Urey, but this experiment did not prove Urey, but this experiment did not prove that life arose from non-life. It actually that life arose from non-life. It actually proved that it takes intelligent design by a proved that it takes intelligent design by a personperson to create the chemicals of life. to create the chemicals of life.