THE CELL

THE CELL

ATOMS MOLECULES COMPOUNDS

ORGANELLESCELLS

THE CELL

• WHAT IS A CELL?– ROBERT HOOKE IN MID-

1960’S OBSERVED CORK WITH A COMPOUND MICROSCOPE

– COINED THE TERM “CELL” TO DESCRIBE WHAT HE OBSERVED

THE CELL

• WHAT IS A CELL?– ANTON VAN

LEEUWENHOEK DEVELOPED NEW MICROSCOPES AND OBSERVED POND WATER

– OBSERVED THINGS NEVER SEEN BEFORE!!

– DIDN’T DRAW ANY CONCLUSIONS, THOUGH…JUST SHARED OBSERVATIONS

THE CELL• WASN’T UNTIL 1800’S THAT SCIENTISTS

STARTED DRAWING CONLCUSIONS/DEVEOPING THEORIES

THE CELL

• SCWANN AND SCHLEIDEN FIRST TO PROPOSE THE BEGINNINGSOF THE:

•CELLTHEORY

THE CELL

THE CELL

• THE CELL THEORY STATES THAT– ALL LIVING THINGS ARE MADE UP OF CELLS– CELLS ARE THE BASIC UNIT OF STRUCTURE AND

FUNCTION IN LIVING THINGS– ALL CELLS ARISE FROM PRE-EXISTING CELLS

THE CELL

• TWO BASIC TYPES OF CELLS– PROKARYOTES VS EUKARYOTES• WHAT IS THE DIFFERENCE??

THE CELL

• PROKARYOTE VS EUKARYOTE

THE CELL

• CELL SIZE– NEED TO COME UP WITH UNITS…(μm)

THE CELL

• μm = MICROMETER• WHAT DOES A

MICROMETER EQUAL??• 1,000 μm = 1 mm

THE CELL

• HOW COME WE NEED MICROMETERS?– CELLS CAN’T BE VERY LARGE…

WHY NOT??– IT IS DUE TO

THE SURFACE AREA TO VOLUMERATIO

THE CELL

THE CELL

• CELLS MUST BE ABLE TO OBTAIN NECESSARY NUTRIENTS AND REMOVE WASTES ACROSS THEIR CELL MEMBRANE AT A RATE THAT SUSTAINS THEIR NEEDS

THE CELL

• NOW THAT WE HAVE ESTABLISHED CELL SIZE, WHAT MAKES UP THE CELL??

THE CELL

• STRUCTURES THAT MAKE UP THE CELL ARE CALLED??– ORGANELLES

• ORGANELLES– CELL WALL– CELL MEMBRANE– NUCLEUS– ENDOPLASMIC

RETICULUM– RIBOSOMES– LYSOSOMES– MITOCHONDRIA– CHLOROPLASTS– ETC…

THE CELL

• CELL WALL– MOST BACTERIA,

VARIOUS OTHER MICROORGANISMS, AND ALL PLANT CELLS

– PROVIDES STRUCTURE AND PROTECTION

– WHAT IS IT MADE OF?• CELLULOSE

THE CELL

• CELL MEMBRANE (A.K.A. PLASMA MEMBRANE)

THE CELL

• CELL MEMBRANE (A.K.A. PLASMA MEMBRANE)– COMPOSED OF CARBS, PROTEINS, AND LIPIDS– PHOSPHOLIPID BILAYER– FUNCTION?• BARRIER BETWEEN

INTERNAL AND EXTERNALENVIRONMENTS

THE CELL

• CELL MEMBRANE (A.K.A. PLASMA MEMBRANE)– SELECTIVELY

PERMEABLE• SOME SUBSTANCES

CAN PASSTHROUGH, WHILE OTHERSUBSTANCESCAN NOT

THE CELL

• NUCLEUS– MEMBRANE-BOUND

STRUCTURE THAT SERVESAS CONTROLCENTER FORMETABOLISM AND CELLULAR REPRODUCTION

– *LARGEST ORGANELLE*– CONTAINS DNA (BLUEPRINTS)

THE CELL

• NUCLEUS– NUCLEAR ENVELOPE• MEMBRANE THAT

SURROUNDS NUCLEUS

– NUCLEOLUS• PLURAL = NUCLEOLI• COMPOSED OF DNA/RNA/PROTEIN• SITE OF RIBOSOMAL PRODUCTION

THE CELL

• CYTOPLASM– WATERY MATERIAL IN THE

CELL BETWEEN THE CELL MEMBRANE ANDNUCLEUS

– CONTAINS DISSOLVED SUBSTANCES THAT ARE A PART OF METABOLIC REACTIONS

– LOCATION OF A VARIETY OF CELLULAR ORGANELLES

THE CELL

• ENDOPLASMIC RETICULUM (E.R.)– ROUGH E.R. VS SMOOTH

E.R.– SYSTEM OF FLUID-FILLED

CANALS– INVOLVED IN INTRA-

CELLULAR TRANSPORT, AND SURFACE AREA FOR METABOLIC REACTIONS WITHIN THE CELL

THE CELL

• RIBOSOMES– COMPOSED OF

RNA AND PROTEIN

– SOLE FUNCTIONIS PROTEIN SYNTHESIS

THE CELL

THE CELL

• GOLGI BODY (A.K.A. GOLGI APPARATUS)– MODIFY,

PACKAGE, AND TRANSPORTPROTEINS MADEBY THE CELLTO THEIR FINAL DESTINATION

THE CELL

THE CELL

• LYSOSOMES– BREAKDOWN BODY– CONTAIN HYDROLYTIC

ENZYMES• ENZYMES THAT

CATALYZE HYDROLYSIS

– LYSOSOMES CAN DIGEST THE ORGANISMIF NOT CONTAINED!! (EX. TAY-SACHS)

– LYSOSOMAL DISEASE

THE CELL• MITOCHONDRIA

– INVOLVED IN CELLULAR RESPIRATION• ATP PRODUCTION (ATP

IS A HIGH ENERGY MOLECULE)

– EVERY EUKARYOTIC CELL HAS THIS ORGANELLE!!

– WE WILL SPEND A WHOLE CHAPTER ON CELLULAR RESPIRATION

THE CELL

• CYTOSKELETON– SUPPORTS CELL,

PROVIDES MOVEMENT

– COMPOSED OFMICROTUBULES ANDMICROFILAMENTS

THE CELL

• VACUOLES– STORAGE SACKS– DIFFERENT TYPES• FOOD VACUOLE• CENTRAL VACUOLE• CONTRACTILE

VACUOLE

THE CELL

• CENTRIOLES– INVOLVED IN CELL DIVISION– NOT FULLY UNDERSTOOD

THE CELL

• CILIA AND FLAGELLA– HAIRLIKE ORGANELLES INVOLVED IN CELLULAR

MOVEMENT

THE CELL

• CHLOROPLASTS

THE CELL• CHLOROPLASTS

– INVOLVED IN PHOTOSYNTHESIS– CONTAIN CHLOROPHYLL (SUBSTANCE THAT MAKES THEM GREEN)– ONE OF THE

GROUP OF ORGANELLES CALLEDPLASTIDS• LEUCOPLASTS• CHROMOPLASTS• CHLOROPLASTS

– PLASTIDS• GROUP OF ORGANELLES

ONLY FOUND INPHOTOSYNTHETIC EUKARYOTES

THE CELL

• REMEMBER, WHAT IS THE DIFFERENCE BETWEEN PROKARYOTIC AND EUKARYOTIC CELLS?

• WHAT ORGANELLES AREN’T IN PROKARYOTES THAT ARE IN EUKARYOTES?

• HOW DID THOSE ORGANELLES GET THERE?

THE CELL

• ENDOSYMBIOTIC THEORY– IT IS BELIEVED

THAT PROKARYOTESFUSED TOGETHERAND FORMEDTHE FIRSTEUKARYOTICCELLS

THE CELL

• MAINTAINING A CONSTANT CELL ENVIRONMENT– THE INTERNAL ENVIRONMENT OF THE CELL MUST

BE KEPT CONSTANT AT ALL TIMES– HOMEOSTASIS• WHAT HAPPENS IF HOMEOSTASIS IS INTERUPTED?

– THE INTERNAL ENVIRONMENT IS CONTROLLED BY HOMEOSTASIS, BUT WHAT ABOUT THE EXTERNAL ENVIRONMENT?• IT IS CONSTANTLY CHANGING!!!

THE CELL

• THE SELECTIVELY PERMEABLE CELL MEMBRANE PROTECTS THE INTERNAL ENVIRONMENT FROM THE CRAZY CHANGES OF THE EXTERNAL ENVIRONMENT

THE CELL

• HOW DO SUBSTANCES THAT CAN GET THROUGH THE MEMBRANE DO IT?

• DIFFUSION– THE

MOVEMENT OF PARTICLESFROM HIGH CONCENTRATIONTO LOWCONCENTRATION

THE CELL

• KEY CONCEPTS WITH DIFFUSION:– EQUILIBRIUM– CONCENTRATION GRADIENT

• DIFFUSION IS VITAL TOWARDS THE MOVEMENT OF PARTICLES/MOLECULES IN AND OUT OF CELLS

THE CELL

• THE CELL MEMBRANE CREATES A BARRIER BETWEEN THE INTERNAL AND EXTERNAL ENVIRONMENT, LEADING TO THE FORMATION OF A CONCETRATION GRADIENT WHICH ALLOWS DIFFUSION TO OCCUR

THE CELL

• WHAT IS THE CELL MEMBRANE MADE UP OF?

THE CELL• SPECIALIZED

PROTEINS IN THE CELL MEMBRANE MAKE DIFFUSION HAPPEN FASTER THAN IT WOULD NATURALLY– FACILITATED

DIFFUSION• DIFFUSION THAT

OCCURS WITH ASSISTANCE (IN THIS CASE, PROTEINS IN THE MEMBRANE)

THE CELL

• WHO REMEMBERS WHAT THE MOST AWESOME, COOL, RADICAL, GNARLIEST INORGANIC COMPOUND IS??

–H2O• BECAUSE WATER IS SO SUPER COOL, IT

HAS ITS OWN TYPE OF DIFFUSION

THE CELL

• OSMOSIS– THE DIFFUSION OF WATER ACROSS A SELECTIVELY

PERMEABLE MEMBRANE– WHAT CAN YOU FILL IN FOR THE WORD

DIFFUSION??– WHY IS WATER

SO DIFFERENT?• BECAUSE STUFF

CAN BE DISSOLVED IN THEWATER

THE CELL

• THE ORIGINAL “U-TUBE”

THE CELL

• OSMOSIS IS SO POWERFUL, IT’S “DEFYING GRAVITY!!”– THIS IS KNOWN

AS OSMOTIC PRESSURE

THE CELL

• EFFECTS OF OSMOSIS ON CELLS– ISOTONIC• NO EFFECT

– HYPOTONIC• SWELLING /

TURGID

– HYPERTONIC• SHRIVELED /

PLASMOLYSIS

THE CELL

• DIFFUSION, FACILITATED DIFFUSION, AND OSMOSIS ALL HAVE SOMETHING IN COMMON– HIGH TO LOW MOVEMENT…

REQUIRING NO INPUT OF ENERGY– MOVEMENT ACROSS A MEMBRANE WITHOUT

ENERGY INPUT IS CALLED

–PASSIVE TRANSPORT

THE CELL

• PASSIVE TRANSPORT VS ACTIVE TRANSPORT– IF PASSIVE TRANSPORT DOESN’T REQUIRE

ENERGY…WHAT DO YOU THINK IS TRUE ABOUT ACTIVE TRANSPORT?

– WHY DOES ACTIVE TRANSPORT REQUIRE ENERGY?

THE CELL

• ACTIVE TRANSPORT– THE MOVEMENT OF MATERIALS FROM LOW

CONCENTRATION TO HIGH CONCENTRATION THROUGH THE EXPENDITURE OF CELLULAR ENERGY (ATP)

– TWO PROCESSES• MOLECULE BY MOLECULE• FORMATION OF VESICLES (VACUOLES)

– ENDOCYTOSIS & EXOCYTOSIS

THE CELL

• EXOCYTOSISVS.ENDOCYTOSIS– PINOCYTOSIS

&PHAGOCYTOSIS

THE CELL

• WHERE DOES THE ENERGY FOR ACTIVE TRANSPORT COME FROM??

• THAT’S WHAT CHAPTER 6 IS ALL ABOUT!!!