Life Structure and Life Structure and ClassificationClassification

What are living things like?• Any living thing is an organism• Organisms • : are organized• : grow and develop• : respond• : maintain homeostasis• :use energy• : reproduce

OrganizedOrganizedAll living organisms are

composed of cellsCells are smallest unit of life that

carries on the function of lifeCells take in materials and use

them in complex waysHave orderly structure and

instruction for transfer of heriditary material

Living Things grow and Living Things grow and DevelopeDevelope

Single cell organisms increase cell size

Multi-celled organisms grow by increasing number of cells

Changes that take place during lifetime is known as development

Figure 2 shows examples of development

Life span is the length of time an organism is expected to live

Living things RespondLiving things RespondLiving things interact with their

surroundingsAnything that causes change in

an organism is a stimulus and the reaction to that is a response

Organisms must respond to stimuli to carry on daily activity and to survive

Maintain HomeostasisMaintain HomeostasisInside cells they must respond to

stimuli within (water or food levels within)

Cells internally make adjustmentsThis regulation of an organism’s

internal life maintaining conditions that is in response to it’s environment is called homeostasis

Living things use Living things use energyenergyAll energy for cells originates from

the sunPlants use sun directly to produce

energy (photosynthesis) where H2O + CO2 produces C6H12O6 (carbohydrates) and O2

Animals and some other organisms take in carbohydrates and oxygen to produce its energy

Some bacteria deep in dark ocean floors use stored energy in chemical compounds to make food

Living things must Living things must reproducereproduce

In order for an organism to continue to its own kind it must be able to reproduce itself

What do living things What do living things need to surviveneed to survive

Place to liveNeeds water

◦Water transport minerals within and between cells

◦Water is released by organisms and homeostasis is maintained

Needs food source◦Animals need to take in food, where

plants produce their own food◦Organisms die and are decomposed

by other organisms that are reused again

How are living things How are living things classifiedclassified

section 2section 2

Carolus Linnaeus◦Developed a system of organizing

organisms by similar structure in system called Binomial Nomenclature.

◦Used Scientific Names rather than common names

◦Modern classification use structure, hereditary information and early stages of development

Binomial NomenclatureBinomial NomenclatureTwo word naming system (latin

names)First word is the genus name

(contain similar species)Second word is the species

name◦Can describe a feature, place or

honor an individual◦Ambystoma tigrinum (salamander

named because of tiger stripes)Organisms of same species can

reproduce amongst themselves

Scientific NamesScientific NamesWhy they are importantWhy they are important

Help avoid confusion with common names

Organisms with similar evolutionary histories are group together

Gives descriptive information about species (tiger salamander)

It is organized efficiently

Classification OrderClassification Order

Organisms are classified in following order:◦Kingdom◦Phylum (Division in plants)◦Class◦Order◦Family◦Genus◦species

Modern ClassificationModern ClassificationToday scientist use phylogeny

to classify organisms◦Uses fossils, evolutionary history

and changes over time to classifySmallest group is a speciesBroadest group is KingdomFigure 6 in book classifies a

brottle nosed dolphin

Tools for Identifying Tools for Identifying OrganismsOrganisms

Field guides and dichotomous keys aide to identify organisms

Dichotomous key (use 2 characteristics that you choose between that leads to identification of organisms)◦The key will lead to genus-species

final name of organism

Cell StructureCell Structuresection 3section 3

Viewing cell structure◦First developed by using two

magnifying glasses together to see larger view of cells

◦Leeuwenhoek (Dutch) saw inside cells (1600’s) called them beasties

Development of Cell Development of Cell TheoryTheory

Hooke in 1665 sliced a piece of cork and saw empty space he called cells

1830 Scheiden used a microscope to study plant parts and called them cells

Schwann observed animal cellsBoth men combined their ideas and

were convinced all living things are made of cells

Mid 1800’s Virchow proposed that cells divide and every cell comes from a cell that already existed

Cell TheoryCell Theorytable 2 (page 221)table 2 (page 221)

All Cells are made up of one or more cells

Cells are the basic unit of organization in organism

All Cells come from pre-existing cells

Cell organizationCell organizationScientists divide cells that have a

membrane bound structure and those that don’t

Cells without a membrane are called prokaryote cells

Cells with a membrane around the cell are called eukaryote cells

Each cell performs specific functions but all cells must take in nutrients, store, produce and breakdown substances, take in and use energy

Structure of cells perform certain functions

Cell WallCell WallTough rigid outer coverings that

protect cells and give them shapeFound in all plants, algae, fungi

and most bacteriaPlants cell wall contain mostly

cellulose (carbohydrate) and allows water and nutrients in and out◦Pectin (found in plant cell walls) is

glue-like structure that has thick structure (jams and jellies)

◦Lignin (makes cell walls rigid) found mostly in plant cells that aide in supporting plants

Cell MembraneCell MembraneAll cells contain a cell membrane

It is the outermost covering of cells unless they have a cell wall

Regulates interactions between cells and environment

Allows nutrients to move in and wastes to leave cell

CytoplasmCytoplasmGell-like substance inside cell

membrane is called cytoplasmLife processes take place hereProkaryote cells cytoplasm contains

the hereditary materialAll organelles are located hereCytoskeleton found in cytoplasm is

made of proteins that help cell change shape, enable some cells to move

Manufacture of Proteins in Manufacture of Proteins in CellsCellsEvery cell activity involves proteinsProteins are part of cell membrane

and are part of all chemical reactions in cell

Ribosomes produce protein in cells◦Found in cytoplasm◦Get their instruction from hereditary

material that tells them how, when and in what order to make specific proteins

Membrane-bound Membrane-bound OrganellesOrganelles

Organelles are structure in cytoplasm that carry out life functions in cells

Found in cytoplasm of eukaryotic cellsNucleus is largest organelle

Ribosomes are not membrane bound but are considered an organelle

Organelles that produce Organelles that produce EnergyEnergy

Chloroplasts: (organelle found in plants)◦Contain chylorophyll (green pigments)

that captures sunlight to make sugars called glucose

◦Captured light energy is stored in glucose as chemical energy where plants utilizes glucose to carry out life functions in cells

Organelles that produce Organelles that produce EnergyEnergy

Organelle that releases energy is Mitochondria

Food (glucose and carbohydrates) is broken down into CO2 and H2O and releases energy

Sometimes called the powerhouse organelle because it provides the energy for cells

All plants and animal cells have these

Organelles that process, Organelles that process, transport and store transport and store

materialsmaterials Endoplasmic reticulum (ER) takes up considerable amount of space that process and move materials around cell like a conveyor belt

Rough ER contains ribosomes where protein is made and moved in cell

Smooth ER process lipids and oils that store energy

Organelles that process, Organelles that process, transport and store transport and store materialsmaterialsAfter proteins is made they are

transferred to Golgi bodies where they are packaged and moved to areas of cells in vesicles

Materials are also moved to outer membrane for release outside of cell

Vacuoles also are organelles that store water, waste products, food and other cell materials

Organelles that Organelles that RecycleRecycle

Lysosomes are structures that break down food molecules, cell waste, worn-out cell parts and viruses

Chemicals released from lysosomes break down food and dead cells

These chemicals are contained in lysosomes and when a cell dies, the chemicals are released and break down the dead cell

Many Celled OrganismsMany Celled OrganismsMany celled organisms rely of other cells to

perform all life functionsTissue is a group of similar cells that work

together to do one jobTissues are organized into organs.Organs are a group of tissues that work

together to perform a function (heart..nerve, blood and cardic muscle tissue)

Group of organs working together perform a certain function is an organ system

Organ systems work together to make up many celled organisms (heart, arteries, veins, and capillaries)

VirusesVirusessection 4section 4

Viruses causes many diseasesViruses are non-living strands of

hereditary material surrounded by a protein coat◦Do not have nucleus, other

organelles or a cell membraneViruses rely on host cells to live

inside (living cells)Have two kinds of viruses: Active and Latent

Active VirusesActive VirusesOccurs when virus enters host

cell and immediately begins to make new viruses

Destroys the host cells when it makes new viruses

Virus uses host cell to duplicate its hereditary material and later releases duplicated virus and kills host cell when they are released

Figure 17 page 232

Latent VirusesLatent VirusesSome viruses enter host cell and

remain inactive for a period of time

Does not immediately cause the host cell to duplicate new virus

At a later time it may begin to duplicate and release new viruses that kill the host cell

AIDS, cold sores are examples

How do viruses affect How do viruses affect organismsorganisms

Viruses attach specific cells that match host cells

Many times viruses only attach to certain host cells (potato leafroll)

Some viruses can affect numerous organisms (rabies)

Viruses are moved by wind and inhaled where they attach

Figure 18 page 233

Treating/Preventing Viral Treating/Preventing Viral DiseasesDiseases

Treatment difficult because antibiotics do not kill viruses

Prevention is best method of avoiding viral infections (eliminate mosquito to fight yellow fever)

Natural ImmunityNatural ImmunityHuman bodies fight viral

infections by making interferonsInterferons are proteins that

make a protective covering for cells that are infected (produced by healthy cells to protect affected cells)

VaccinesVaccinesVaccines are weakened viruses

that can’t enter host cells and duplicate, but cells begin to make interferons that protect all cells from infection

Measles, mumps, small pox, chicken pox, polio, and rabies

Found vaccine by taking weakened cow pox cells and entering them into healthy people to prevent small pox (1786) Jenner

Virus ResearchVirus ResearchAIDS is a disease that is caused by

human immuno-deficiency virus (HIV)

AIDS (acquired immune deficiency syndrome)

The HIV virus weakens the immune system and body can’t fight infections like pneumonia, TB

People usually die from weakened system rather than disease