Here’s what a “cell” is!Here’s what a “cell” is!

CellCell - the smallest unit of an - the smallest unit of an organism that carries on the organism that carries on the functionsfunctions of life of life

A cell can perform all the A cell can perform all the processesprocesses of of lifelife..

•Many Sizes:

•nerve cells - up to a meter long

•human egg cell - dot of an i

•bacteria - 80,000 could fit in the dot of an i

•Different shapes:

•Related to their function (job)

•Cell types:

•Prokaryotic cell –

very simple; no membrane-bound structures

(ex: bacteria)

•Eukaryotic cell –

more advanced; has membrane- bound structures

(ex: animal cells, plant cells)

Early Cell ScientistsEarly Cell ScientistsRobert HookeRobert Hooke (1665) (1665)

An English scientist who An English scientist who looked at slices of looked at slices of corkcork under a crude compound under a crude compound microscope and saw “a microscope and saw “a great many great many little boxeslittle boxes” ” that he called “cells.” that he called “cells.” First person to see cells. First person to see cells.

““Cell” comes from the Cell” comes from the Latin word for Latin word for ““little roomlittle room.”.”

Early Cell ScientistsEarly Cell Scientists

Anton van LeeuwenhoekAnton van Leeuwenhoek (1673)(1673)

A Dutch shopkeeper who A Dutch shopkeeper who looked at pond water using a looked at pond water using a simple microscopesimple microscope and saw and saw what he called “what he called “animalculesanimalcules.”.”

Today, we call them single-Today, we call them single-celled celled organismsorganisms..

An Early Simple Microscope

Early Cell ScientistsEarly Cell Scientists

Matthias SchleidenMatthias Schleiden (1838) (1838) A German botanist who discovered A German botanist who discovered

that all plants are made up of that all plants are made up of similar similar unitsunits, or cells., or cells.

Early Cell ScientistsEarly Cell Scientists

Theodor SchwannTheodor Schwann (around 1830)(around 1830)

A German scientist who stated that all A German scientist who stated that all plants plants andand animals are made up of animals are made up of building blocksbuilding blocks, or cells., or cells.

He also observed that there are He also observed that there are similaritiessimilarities and and differencesdifferences between between plant and animal cells.plant and animal cells.

Early Cell ScientistsEarly Cell Scientists

Rudolph VirchowRudolph Virchow (1858) (1858) This German physician also This German physician also

reported that every living thing is reported that every living thing is made of up vital units, known as made of up vital units, known as cellscells. He also predicted that . He also predicted that cellscells come from othercome from other cellscells..

Cell TheoryCell Theory

1. All living things are made up of 1. All living things are made up of one one or more cellsor more cells..

2. Cells are the 2. Cells are the basic unitbasic unit of of structurestructure and and functionfunction in living things. in living things.

3. All cells come only from 3. All cells come only from other livingother living cells.cells.

Cell StructureCell StructureAnimal Cell Plant Cell

Cell StructureCell Structure

A cell is like a A cell is like a small townsmall town::Different parts have different and Different parts have different and specialized specialized jobsjobs..

Plant cells and animal cells have Plant cells and animal cells have

many many similarsimilar structures, but have structures, but have

several important several important differencesdifferences..

Cell MembraneCell Membrane

Structure:

•Outer boundary of the cell

•Phospholipid bilayer membrane

•Selectively permeable

Cell MembraneCell MembraneFunction (job):

•Protects inside

•Supports/gives shape

•Controls what enters/leaves - “gatekeeper”

•Helps maintain homeostasis (ability to keep a stable environment)

Cell WallCell Wall

Structure:

•ONLY IN PLANTS

•Made of cellulose

•Strong & rigid

•Dead layer

Cell WallCell WallFunction (job):

•Protects/supports

•Gives shape

CytoplasmCytoplasm

Structure:

•Jelly-like substance

•80% water

CytoplasmCytoplasm

Function (job):

•Organelles float in cytoplasm

•Materials for growth are found in cytoplasm

•Expels waste through cell membrane

NucleusNucleus

Structure:

•Surrounded by nuclear membrane

•Usually round/oval

•Near center

NucleusNucleus

Function (job):

•Control center of cell

•Controls cell activities

•Contains chromosomes

MitochondriaMitochondria

Structure:

•Has an outer membrane and an inner folded membrane

•Rod shaped

MitochondriaMitochondria

Function (job):

•Cellular respiration

•Turns food into useable energy (ATP)

RibosomesRibosomes

Structure:

•Tiny, round, dark

•Can be free floating or attached to endoplasmic reticulum

RibosomesRibosomes

Function (job):

•Protein factories

•Assembles proteins used in growth, repair and control

Endoplasmic ReticulumEndoplasmic Reticulum

Structure:

•Network of tubes and canals

•Smooth ER - no ribosomes attached

•Rough ER - ribosomes are attached

Endoplasmic ReticulumEndoplasmic Reticulum

Function (job):

•Transports materials “intracellular highway”

Golgi BodiesGolgi Bodies

Structure:

•Series of flattened sacs

Golgi BodiesGolgi BodiesFunction (job):

•Processes, packages and secretes material

•Materials that are transported by the ER usually stop first at the Golgi bodies where they are stored or altered before moving to other parts of the cell

LysosomesLysosomes

Structure:

•ONLY IN ANIMAL CELLS

•Contains powerful digestive chemicals

LysosomesLysosomes

Function (job):

•Contains digestive enzymes (chemicals), breaks things down

•“suicide sac”

VacuolesVacuoles

Structure:

•Fluid-filled sacs that float in the cytoplasm

VacuolesVacuolesFunction (job):

•Stores water and food materials

•Stores waste and helps the cell get rid of waste

•Plant cells contain a large central vacuole - filled with water - helps give shape

ChloroplastChloroplast

Structure:

•ONLY IN PLANT CELLS

•Green, oval-shaped

•Contains green pigment chlorophyll

ChloroplastChloroplast

Function (job):

•Site of photosynthesis

•Traps the sun’s energy to make glucose

How are plant and animal How are plant and animal cells different?cells different?

PLANT CELLS:

Have cell walls,

chloroplasts,

large vacuoles

How are plant and animal How are plant and animal cells different?cells different?

ANIMAL CELLS:

Have lysosomes

How are different cells How are different cells adapted to their functions?adapted to their functions?

Muscle Cells: Have large

quantities of mitochondria for

energy.

Plant Cells: Rigid cell walls allow plants to grow upright.

How are different cells How are different cells adapted to their functions?adapted to their functions?

Red Blood Cells: Thin, flexible discs allow them to squeeze through tiny blood vessels.

Nerve Cells: Have long projections through which

messages are sent throughout the body.

VocabularyVocabulary

PermeablePermeable

DiffusionDiffusion

OsmosisOsmosis

MitosisMitosis

ChromosomeChromosome

CentrioleCentriole

CentromereCentromere

Organization of Living Organization of Living ThingsThings

Five main levels of organizationFive main levels of organization

1.1. CellCell

2.2. TissueTissue

3.3. OrganOrgan

4.4. Organ SystemOrgan System

5.5. OrganismOrganism

TissueTissue

Example: Example: MuscleMuscle Tissues are made of specialized Tissues are made of specialized

cells.cells.

OrganOrgan

Examples: Examples: Heart, Lung, BrainHeart, Lung, Brain Found in both plants and Found in both plants and

animals.animals. Composed of tissue that is Composed of tissue that is

organized into groups that work organized into groups that work together to perform special together to perform special functions.functions.

Organ SystemOrgan System

Example: Example: Circulatory SystemCirculatory System A group of organs that work A group of organs that work

together.together.

10 Organ Systems in complex 10 Organ Systems in complex organismsorganisms

(humans, dogs, birds, etc.)(humans, dogs, birds, etc.)

1.1.CirculatoryCirculatory

2.2.DigestiveDigestive

3.3.NervousNervous

4.4.RespiratoryRespiratory

5.5.SkinSkin

6.6.SkeletalSkeletal

7.7.MuscularMuscular

8.8.ReproductiveReproductive

9.9.ExcretoryExcretory

10.10.EndocrineEndocrine

ORGANISMSORGANISMS

Different Different organ systemsorgan systems work work together to keep the together to keep the organism alive.organism alive.

QUESTION:QUESTION:

Classify the following as a tissue, Classify the following as a tissue, organ, or organ system.organ, or organ system.a. Brain, spinal cord, and nerves a. Brain, spinal cord, and nerves b. Heartb. Heartc. Group of muscle cellsc. Group of muscle cells

QUESTION:QUESTION:

Can a single-celled organism Can a single-celled organism contain tissue? Explain.contain tissue? Explain.

QUESTION:QUESTION:

Give one example of each:Give one example of each:a. Cella. Cell c. Tissuec. Tissueb. Organb. Organ d. Organismd. Organism