Living SystemsLiving Systems

OrganismsOrganisms

7th GradeGrade Science

A- A- OrganismsOrganisms,, (any living thing) share certain characteristics that set them apart from nonliving things.

I- Living Things Carry Out Life I- Living Things Carry Out Life ProcessesProcesses

B- B- LifeLife ProcessesProcesses::

1-Getting and using energy1-Getting and using energy

a-Nutrition: Taking in food (ingestioningestion) & breaking it down into a usable molecule

(digestiondigestion).

b-Transport: Move materials throughout organism.

c-Respiration: Releasing energy stored in food.

2- 2- GettingGetting ridrid ofof wasteswastes:: Excretion

3- 3- RespondRespond toto changeschanges inin thethe EnvironmentEnvironment:: Regulation (Stimulus Stimulus causes a Response)causes a Response)

4- Growth & Development: Changing food into more of themselves.

5- Reproduction: Making of more organisms of same kind to ensure the survival of the species.

TheThe CellCell BasicBasic UnitUnit ofof LifeLife::

1- 1- CellCell TheoryTheory:: States that all States that all organisms are made organisms are made

of cells or of cells or of a cell, all cells of a cell, all cells come from other come from other cells. cells.

2- 2- CellsCells VaryVary::

a- size, shape, and a- size, shape, and arrangement.arrangement.

b- b- UnicellularUnicellular: one cell: one cell

c- c- MulticellularMulticellular: many : many cells.cells.

3- 3- PartsParts andand FunctionFunction ofof AnimalAnimal CellsCells

a- a- CellCell MembraneMembrane: thin : thin structure covering the structure covering the surface of the cell.surface of the cell.

•Allows materials needed by cell Allows materials needed by cell to enter and wastes to leaveto enter and wastes to leave..

b- b- CytoplasmCytoplasm: jellylike substance : jellylike substance that fills cell. Contains that fills cell. Contains

proteins proteins for growth and for growth and repair. repair.

Mitochondria

Vacuoles

Nucleus Cell membrane

Chromosomes

Rough endoplasmic reticulum

Cytoplasm

Nuclear membrane

Ribosome

Smooth endoplasmic reticulum

c- c- OrganellesOrganelles: tiny structures in : tiny structures in cytoplasm cytoplasm that perform special that perform special

jobs.jobs.

NucleusNucleus: : “Control Center”“Control Center” Controls cell activities. These are Controls cell activities. These are stored in the stored in the chromosomeschromosomes found in nucleus on found in nucleus on genesgenes. .

NuclearNuclear membranemembrane: allows : allows information to enter and leave information to enter and leave nucleus.nucleus.

MitochondriaMitochondria: : “Powerhouse”“Powerhouse” cell cell respiration respiration food is burned by food is burned by combining it with oxygen to combining it with oxygen to release energy.release energy.EndoplasmicEndoplasmic reticulumreticulum:: channels that run throughout the channels that run throughout the cell store and transport cell store and transport materials. materials. RibosomeRibosome proteins proteins used for growth and repair.used for growth and repair.VacuolesVacuoles: stores materials.: stores materials.

4-4-PlantPlant CellsCells differdiffer fromfrom AnimalAnimal CellsCells

a- a- CellCell WallWall:: gives support and gives support and shapeshape

b- b- ChlorophyllChlorophyll:: contains contains chloroplast chloroplast for carrying out for carrying out photosynthesis.photosynthesis.

c- c- LargeLarge VacuolesVacuoles:: stores stores mostly mostly water. water.

ribosomenucleus

nuclear membranechromosomes

Smooth Endoplasmic reticulum

Cell membrane

cytoplasm

mitochondria

Cell Wall

VacuoleChlorophyll

Rough Endoplasmic reticulum

5-5- BacteriaBacteria cellscells have no nucleus, mitochondria, or endoplasmic reticulum. They still carry out all five life processes.Cell Wall

Cell membrane

Cytoplasm Ribosomes

Chromosome

MicroorganismsMicroorganisms: Are unicellular organisms1-1-HarmfulHarmful MicroorganismsMicroorganisms: Cause

infectious diseases that can be passed on from one organism to the next.

a.a. NoninfectiousNoninfectious diseasesdiseases: : Diseases that are not caused by microorganisms.

~~High blood pressure, asthma, cancer etc.. ~~Causes = poor diet, allergies, chemicals,

heredity etc…

2-Helpful Microorganisms: about 5%a. Examples:

~~ DecomposersDecomposers: Break down dead materials and return nutrients back into soil.~~ YeastYeast:: bread, wine, and beer. ~ ~ MoldMold:: Cheese, and medicine

A- The Life ProcessesA- The Life Processes

Getting and Using EnergyGetting and Using Energy

•Getting ride of wastesGetting ride of wastes

•Growth and DevelopmentGrowth and Development

•Responding to Changes in Responding to Changes in EnvironmentEnvironment

•ReproductionReproduction

1-Transport: is the movement of materials through organism. Water is a key nutrient for this to occur.

*Two types:

DiffusionDiffusion molecules move from a high concentration to a low concentration with out the use of energy. OsmosisOsmosis: diffusion of water.

ActiveActive TransportTransport used by cells need to move molecules from low concentration to a high

concentration. Cells require the use of energy.

A Closer look at Life Processes:

2- 2- GettingGetting andand usingusing energyenergy: :

a- Nutrition plants: GreenGreen plants make own food. Through the processes of photosynthesisphotosynthesis

* PhotosynthesisPhotosynthesis: plants use energy from the sun and change carbon dioxide COCO22 and water HH22OO into sugar CC66HH1212OO66. Energy from the sun is therefore stored in sugar.

*PhotosynthesisPhotosynthesis produces oxygen O2.

*Chlorophyll greengreen pigment in leaves contains chloroplast needed for photosynthesis.

b-b-NutritionNutrition AnimalsAnimals:: get energy “nutritionnutrition” by eating other plants or animals. The original source of energy is the sun. “WaterWater” is also an important part of nutrition in plants and animals.c- c- RespirationRespiration:: is the processes that organisms use to release “burnburn” energy stored in food. Respiration is the opposite of Photosynthesis.

PhotosynthesisPhotosynthesis: energy + carbon dioxide + water = sugar + oxygen

RespirationRespiration: sugar + oxygen = energy + carbon dioxide + water

All organisms get energy All organisms get energy directly or indirectly from the directly or indirectly from the

SUNSUN

3- 3- GettingGetting rideride ofof wasteswastes : : “ExcretionExcretion” process of removing waste from the body. Filtered out of blood.

a-Wastes = Carbon dioxide, urea, salt & excess water.

b-Wastes are removed by exhaling, perspiring, and urinating in

animals, and by transpiration in plants.

4-4-RespondingResponding toto changeschanges inin thethe

environment:environment: regulationregulation Organisms respond to internal and external changes in their environment known as StimuliStimuli.

a- Examples = migration, drinking, perspiring, hibernation,

growing of fur etc..

b- Regulation helps organisms maintain ““homeostasishomeostasis”” the maintenance of a constant internal environment.

5-5-ReproductionReproduction:: Organisms reproduce to ensure the survival of species.

a-a- Two Types of reproduction:

1)1) AsexualAsexual ReproductionReproduction: process of producing a new organism with only one parent. The new organism has the exact same DNA as the parent.

b-b- Types of Asexual Reproduction:Fission or Binary Fission:Fission or Binary Fission: one cell

splits to form two cells with the same DNA

BuddingBudding:: a new organism grow from the body of the parent. The bud can stay on to form a colony, or break apart

Regeneration: A new organism forms from a piece of the parent or the parent re-grows the missing piece

SporulationSporulation: Some organisms produce reproductive cells in

a protective covering called a Spore.

2)2) Sexual Reproduction Sexual Reproduction involves the combination of DNA from two parents. Fertilization is the joining of DNA from The male (SPERM, POLLEN)(SPERM, POLLEN) and DNA of the female (EGG).(EGG). The new organisms is a combination of both parents.