Basic Structure of a Cell

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Review Facts Review Facts About Living About Living

ThingsThings

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What Are the Main What Are the Main Characteristics of Characteristics of

organisms?organisms?1. Made of CELLS2. Require ENERGY (food)3. REPRODUCE (species)4. Maintain HOMEOSTASIS5. ORGANIZED6. RESPOND to environment7. GROW and DEVELOP8. EXCHANGE materials with

surroundings (water, wastes, gases)

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LEVELS OF ORGANIZATIONLEVELS OF ORGANIZATION

Nonliving Levels:

1.ATOM (element)

2.MOLECULE (compounds like carbohydrates & proteins)

3.ORGANELLES (nucleus, ER, Golgi …)

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LEVELS OF ORGANIZATIONLEVELS OF ORGANIZATIONLiving Levels:

1.CELL (makes up ALL organisms)

2.TISSUE (cells working together

3.ORGAN (heart, brain, stomach …)

4.ORGAN SYSTEMS (respiratory, circulatory …)

5.ORGANISM

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LEVELS OF ORGANIZATIONLEVELS OF ORGANIZATIONLiving Levels continued:1.POPULATION (one species in an area)2.COMMUNITY (several populations in

an area3.ECOSYSTEM (forest, prairie …)4.BIOME (Tundra, Tropical Rain forest…)5.BIOSPHERE (all living and nonliving

things on Earth)

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History of Cells & the History of Cells & the Cell TheoryCell Theory

Cell Specialization 7

CELL THEORY•All living things are

made of cells•Cells are the basic unit

of structure and function in an organism (basic unit of life)

•Cells come from the reproduction of existing cells (cell division)

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Exceptions to the Exceptions to the cell theory-

1.1. VirusesViruses: they are able : they are able to to reproducereproduce only only within a within a livingliving cell. cell.

2. Slime mold.2. Slime mold.

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3.3. MitochondriaMitochondria and and ChloroplastsChloroplasts•A) each contain their own A) each contain their own genetic information genetic information different than that in the different than that in the nucleus. nucleus.

– Mitochondrial DNA is called Mitochondrial DNA is called mDNAmDNA..•B) are able to reproduce B) are able to reproduce by themselvesby themselves

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Cell TypesCell Types• Cells, the basic units of organisms, can

only be observed under microscope• Three Basic types of cells include:

Animal Cell Plant CellBacterial

Cell11

Multicellular OrganismsMulticellular Organisms• Cells in multicellular organisms

often specialize (take on different shapes & functions)

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Cell SpecializationCell Specialization•Cells in a multi-

cellular organism become specialized by turning different genes on and off

•This is known as DIFFERENTIATION

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Specialized CellsRed blood cells

Cheek cells

Xylem cells

Pollen

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ATOMS MOLECULES ORGANELLES

Nonliving LevelsNonliving Levels

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CELLS – life starts here

TISSUES – Similar cells working together

Living LevelsLiving Levels

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ORGANS ORGAN SYSTEMS ORGANISM

Different tissuesworking together

Different organsworking together

More Living LevelsMore Living Levels

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Living vs. Non-living

• Biotic Factor- Biological influence on organisms within an ecosystem… Living

• Abiotic Factor- Physical, or non-living, factor that shapes an ecosystem. Example: Water

Prokaryotes – The first Prokaryotes – The first CellsCells

• Cells that lack a nucleus or membrane-bound organelles

• Includes bacteria• Simplest type of cell• Single, circular chromosome

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video

ProkaryotesProkaryotes• Nucleoid region

(center) contains the DNA

• Surrounded by cell membrane & cell wall

• Contain ribosomes in their cytoplasm to make proteins

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Eukaryotes• Cells that HAVE a

nucleus and membrane-bound organelles

• Includes protists, fungi, plants, and animals

• More complex type of cells

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Eukaryotic CellContain 3 basic

cell structures:•Nucleus•Cell Membrane•Cytoplasm with

organellesVideo

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Two Main Types of Eukaryotic Cells

Plant CellAnimal

Cell23

OrganellesOrganelles•Very small (Microscopic)•Perform various functions for

a cell•Found in the cytoplasm•May or may not be

membrane-bound

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http://videos.howstuffworks.com/science/cells-videos-playlist.htm#video-28732

Animal Cell OrganellesAnimal Cell Organelles

NucleolusNucleus

Nuclear envelope

Ribosome (attached)Ribosome (free)

Cell Membrane

Rough endoplasmic reticulum

Golgi apparatus

MitochondrionSmooth endoplasmicreticulum

Centrioles

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Plant Cell OrganellesPlant Cell Organelles

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Cell or Plasma MembraneCell or Plasma Membrane

Outsideof cell

Insideof cell(cytoplasm)

Cellmembrane

Proteins

Proteinchannel Lipid bilayer

Carbohydratechains

• Composed of double layer of phospholipids and proteins

• Surrounds outside of ALL cells• Controls what enters or leaves the cell• Living layer

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The Cell Membrane is The Cell Membrane is FluidFluid

Molecules in cell membranes are constantly moving and changing

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•Lies immediately against the cell wall in plant cells

•Pushes out against the cell wall to maintain cell shape

Cell Membrane in PlantsCell Membrane in PlantsCell membrane

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•Nonliving layer•Found in plants, fungi, & bacteria

•Made of cellulose in plants

•Supports and protects cell

•Found outside of the cell membrane

Cell wallCell WallCell Wall

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•Jelly-like membrane

•Provides a medium for chemical reactions to take place

•Contains organelles to carry out specific jobs

•Found in ALL cells

Cytoplasm of a Cytoplasm of a Cell Cell cytoplas

m

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•Controls the normal activities of the cell

•Contains the DNA in chromosomes

•Bounded by a nuclear envelope (membrane) with pores

•Usually the largest organelle

The Control Organelle - The Control Organelle - NucleusNucleus

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•Each cell has fixed number of chromosomes that carry genes

•Genes control cell characteristics

Nucleus

More on the More on the NucleusNucleus

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Inside the Nucleus -The genetic material (DNA) is

found

DNA is spread out And appears as

CHROMATINin non-dividing cells

DNA is condensed & wrapped around proteins forming

as CHROMOSOMES in dividing cells

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What Does DNA do?What Does DNA do?DNA is the hereditary

material of the cell

Genes that make up the DNA molecule code for different proteins

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CytoskeletonCytoskeleton• Helps cell maintain

cell shape• Also help move

organelles around• Made of proteins• Microfilaments are

threadlike & made of ACTIN

• Microtubules are tube-like & made of TUBULIN

MICROTUBULES

MICROFILAMENTS

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CentriolesCentrioles• Found only in animal cells• Paired structures near nucleus• Made of bundle of

microtubules• Appear during cell division

forming mitotic spindle• Help to pull chromosome pairs

apart to opposite ends of the cell

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MitochondrionMitochondrion(plural = mitochondria)(plural = mitochondria)

• “Powerhouse” of the cell

• Generate cellular energy (ATP)

• More active cells like muscle cells have MORE mitochondria

• Both plants & animal cells have mitochondria

• Site of CELLULAR RESPIRATION (burning glucose) 38

MITOCHONDRIASurrounded by a

DOUBLE membrane

Folded inner membrane called CRISTAE (increases surface areafor more chemical Reactions)

Has its own DNA

Interior called MATRIX39

Interesting Fact ---Interesting Fact ---• Mitochondria

Come from cytoplasm in the EGG cell during fertilization

Therefore …• You inherit your

mitochondria from your mother!

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Rod shape

Cell PowerhouseCell Powerhouse

Mitochondrion( mitochondria )

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What do mitochondria What do mitochondria do?do?

Burns glucose to release energy (ATP)

Stores energy as ATP

“Power plant” of the cell

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Endoplasmic Reticulum - EREndoplasmic Reticulum - ER

Two kinds of ER ---ROUGH & SMOOTH

• Functions in Synthesis of cell products & Transport

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Rough Endoplasmic Reticulum Rough Endoplasmic Reticulum (Rough ER)(Rough ER)

• Has ribosomes on its surface

• Makes membrane proteins and proteins for EXPORT out of cell

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Rough Endoplasmic Rough Endoplasmic Reticulum (Rough ER)Reticulum (Rough ER)

• Proteins are made by ribosomes on ER surface

• They are then threaded into the interior of the Rough ER to be modified and transported

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Smooth Endoplasmic Smooth Endoplasmic ReticulumReticulum

• Smooth ER lacks ribosomes on its surface

• Is attached to the ends of rough ER

• Makes cell products that are USED INSIDE the cell

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Functions of the Smooth Functions of the Smooth ERER•Makes membrane

lipids (steroids)•Regulates calcium

(muscle cells)•Destroys toxic

substances (Liver)

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RibosomesRibosomes• Made of PROTEINS and rRNA• “Protein factories” for cell• Join amino acids to make proteins• Process called protein synthesis

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RibosomesRibosomesCan be attached to

Rough ER

OR

Be free (unattached

) in the cytoplasm

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Golgi BodiesGolgi BodiesLook like a stack of pancakes

Modify, sort, & packagemolecules from ERfor storage OR transport out of cell

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LysosomesLysosomes• Contain Contain digestive digestive

enzymesenzymes• Break down Break down food, food,

bacteria,bacteria, and worn out and worn out cell parts for cells cell parts for cells

• Programmed forProgrammed for cell cell death (AUTOLYSIS)death (AUTOLYSIS)

• Lyse (break open) & Lyse (break open) & release release enzymes to break enzymes to break down & recycle cell parts)down & recycle cell parts)

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Lysosome DigestionLysosome Digestion

• Cells take in food by phagocytosis• Lysosomes digest the food & get rid of wastes

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Cilia & FlagellaCilia & Flagella• Cilia are

shorter and more numerous on cells

• Flagella are longer and fewer (usually 1-3) on cells

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VacuolesVacuoles• Fluid filled sacks for storage• Small or absent in animal cells• Plant cells have a large Central Vacuole• No vacuoles in bacterial cells

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VacuolesVacuoles• In plants, they

store Cell Sap• Includes storage of

sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes

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Contractile Contractile VacuoleVacuole

• Found in unicellular protists like paramecia

• Regulate water intake by pumping out excess (homeostasis)

• Keeps the cell from lysing (bursting)

Contractile vacuole animation

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ChloroplastsChloroplasts• Found only in producers (organisms

containing chlorophyll)• Use energy from sunlight to make

own food (glucose)• Energy from sun stored in the

Chemical Bonds of Sugars

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ChloroplastsChloroplasts• Surrounded by DOUBLE

membrane• Contains its own DNA• Contains enzymes &

pigments for Photosynthesis

• Never in animal or bacterial cells

• Photosynthesis – food making process

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