UNIT 2: CELL STRUCTURE & FUNCTION

GOALS

• CONSTRUCT A HIERARCHY OF LIFE FROM CELLS TO ECOSYSTEMS

• RELATE THE DEVELOPMENT OF THE CELL THEORY TO CURRENT TRENDS IN CELLULAR BIOLOGY

• COMPARE AND CONTRACT EUKARYOTES AND PROKARYOTES

CELL HIERARCHY

CELL TISSUE ORGAN ORGAN SYSTEM

ORGANISM

 Smallest unit of life 

 

 

 Groups of cells with similar function

 Two or more types of tissues that work together

 Group of organs that carry out a set of functions

 Has several organ systems that function together

Ex: Skin cell Ex: Muscle Ex: Heart Ex: Respiratory system

Ex: Human

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ANTON VAN LEEUWENHOEK

• USED SINGLE-LENS MICROSCOPE TO OBSERVE POND WATER• FOUND TINY LIVING ORGANISMS

THEODOR SCHWANN*

• GERMAN BIOLOGIST WHO STATED THAT ALL ANIMALS WERE MADE OF CELLS

MATTHIAS SCHLEIDAN*

• GERMAN BOTANIST THAT STATED ALL PLANTS WERE MADE OF CELLS

RUDOLPH VIRCHOW*

• GERMAN DOCTOR CONCLUDED THAT NEW CELLS WOULD BE PRODUCED ONLY FROM THE DIVISION OF NEW CELLS

CELL THEORY

• ALL LIVING THINGS ARE COMPOSED OF CELLS

• CELLS ARE THE BASIC UNITS OF STRUCTURE AND FUNCTION IN LIVING THINGS

• NEW CELLS ARE PRODUCED FROM EXISTING CELLS

• CENTRAL PIECE OF EQUIPMENT: MICROSCOPE

NUCLEUS

• LARGE MEMBRANE-ENCLOSED STRUCTURE THAT CONTAINS DNA

PROKARYOTES

• CELLS THAT DO NOT HAVE A NUCLEUS

• SMALLER

• SIMPLER

• BACTERIA

EUKARYOTES

• CELLS THAT DO CONTAIN A NUCLEUS

• LARGER

• MORE COMPLEX

• DNA IN NUCLEUS, MANY INTERNAL STRUCTURES

GOALS

• DESCRIBE THE ROLE OF ORGANELLES, RIBOSOMES & CYTOSKELETON

• COMPARE AND CONTRAST THE STRUCTURES OF AN ANIMAL CELL TO A PLANT CELL

WHAT’S AN ORGANELLE?

• THINK OF IT AS A “CELL ORGAN”

• ONLY FOUND IN EUKARYOTIC CELLS

NUCLEUS

• CONTAINS THE CELL’S DNA

• SURROUNDED BY NUCLEAR ENVELOPE

RIBOSOMES

• ASSEMBLE (PUT TOGETHER) PROTEINS BY FOLLOWING INSTRUCTIONS FROM THE NUCLEUS

• SMALL PARTICLES OF RNA & PROTEIN

• FOUND IN THE CYTOPLASM OR ON THE ROUGH ER

• SMALL MACHINE IN A FACTORY

ROUGH ENDOPLASMIC RETICULUM

• PROTEIN SYNTHESIS (MAKING PROTEINS)

• RIBOSOMES ARE ON THE SURFACE…THAT’S WHAT MAKES IT ROUGH!

• PROTEINS LEAVE THE RIBOSOMES, GO INTO THE ROUGH ER

SMOOTH ENDOPLASMIC RETICULUM

• NO RIBOSOMES ON SURFACE

• CONTAINS ENZYMES

• SYNTHESIZE (MAKE) MEMBRANE LIPIDS

• DETOXIFY DRUGS

GOLGI BODIES

• PROTEINS GO FROM ROUGH ER TO GOLGI APPARATUS

• MODIFIES, SORTS AND PACKAGES PROTEINS

• THEN SHIPS PROTEINS TO THEIR FINAL DESTINATION

LYSOSOMES

• FILLED WITH ENZYMES

• BREAKDOWN LIPIDS, CARBS AND PROTEINS

• BREAKDOWN OLD ORGANELLES

• THINK OF THEM AS THE “CLEAN UP CREW”

VACUOLES

• STORE MATERIALS LIKE WATER, SALTS, PROTEINS AND CARBS

• SACLIKE STRUCTURE

• CAN BE FOUND IN SOME SINGLE CELLED ORGANISMS FOR MOVEMENT

CENTRAL (LARGE) VACUOLE

• PLANT CELLS HAVE SINGLE LARGE VACUOLE FILLED WITH LIQUID• GIVES STRENGTH TO PLANTS TO HOLD UP LEAVES AND FLOWERS

MITOCHONDRIA

• CELL “POWER HOUSE”

• TWO MEMBRANES

• CONVERT CHEMICAL ENERGY FROM FOOD INTO COMPOUNDS THE CELL CAN USE

• ONLY INHERITED FROM MOM

CHLOROPLAST

• FOUND IN PLANTS

• CAPTURE ENERGY FROM SUNLIGHT AND CONVERT IT TO CHEMICAL ENERGY• PHOTOSYNTHESIS

• THINK OF “SOLAR POWER PLANTS”

• TWO MEMBRANES

• CONTAIN PIGMENT (COLOR)-CHLOROPHYLL

MOVING ON TO STRUCTURE…

• MICROTUBULE-HOLLOW STRUCTURES MADE OF PROTEINS, HELP WITH CELL SHAPE

• MICROFILAMENT-THREADLIKE STRUCTURES MADE OF PROTEIN

CENTRIOLES

• LOCATED NEAR THE NUCLEUS

• FOUND IN PAIRS

• ORGANIZE CELL DIVISION (MITOSIS/MEIOSIS)

• MADE OF MICROTUBULES

• NOT FOUND IN PLANT CELLS

CELL WALL

• FOUND IN PLANTS

• PROVIDES SUPPORT AND PROTECTION FOR THE CELL

• MADE OF CELLULOSE (WHICH IS A CARB!)• WOOD AND PAPER

CELL (PLASMA) MEMBRANE

• DETERMINES WHAT ENTERS AND EXITS THE CELL

• PROVIDES PROTECTION AND SUPPORT

• COMPOSED OF LIPID BILAYER (DOUBLE-LAYERED SHEETS)

CYTOPLASM

• THICK SOLUTION-THINK OF “GOO”• MADE OF WATER, SALTS AND PROTEINS

• PORTION OF THE CELL OUTSIDE OF THE NUCLEUS

CYTOSKELETON

• IN EUKARYOTES

• HELPS SUPPORT THE CELL (SHAPE)

• HELPS WITH MOVEMENT-CILIA AND FLAGELLA• THINK OF HAIR AND TAILS

• MADE UP OF MICROFILAMENTS & MICROTUBULES

PLANT VS. ANIMAL CELL

GOALS

• RELATE THE FUNCTION OF THE PLASMA MEMBRANE TO ITS STRUCTURE

• COMPARE AND CONTRAST ACTIVE TRANSPORT AND PASSIVE TRANSPORT MECHANISMS:

• DIFFUSION

• OSMOSIS

• ENDOCYTOSIS

• EXOCYTOSIS

• PHAGOCYTOSIS

• PINOCYTOSIS

PHOSPHOLIPID BILAYER

• BASIC LIPID:

• HYDROPHILIC-WATER LOVING (POLAR)

• HYDROPHOBIC-WATER FEARING (NONPOLAR)

PHOSPHOLIPID BILAYER

• TWO LAYERS OF LIPID MOLECULES

• FOUND IN ALL CELL MEMBRANES

• BARRIER FOR THE CELL (ALLOWS THINGS IN AND OUT)

• ONLY ALLOWS WATER AND GAS TO PASS THROUGH FREELY

• LARGE AND SMALL POLAR MOLECULES CANNOT CROSS

WITHOUT HELP

PHOSPHOLIPID BILAYER

PROTEINS

• ALLOW FOR INTERACTIONS BETWEEN CELLS

• TWO TYPES IN MEMBRANE:• INTEGRAL-EMBEDDED, SPAN THE ENTIRE MEMBRANE

• PERIPHERAL-ON EDGE OF MEMBRANE, MOVE MORE FREELY

• TRAVEL!

• ALSO CAN TRANSMIT SIGNALS

CARBOHYDRATES

• ATTACHED TO PROTEISN OR LIPIDS OUTSIDE CELL MEMBRANE

• PROVIDES CUSHIONING AND PROTECTION FOR THE MEMBRANE

• HELPS WITH CELL RECOGNITION

CHOLESTEROL

• HELPS TO KEEP FLUIDITY

• POSITIONED BETWEEN PHOSPHOLIPIDS

• PREVENTS POSSIBLE CRYSTALLIZATION

• MADE UP OF 4 RINGS (STRUCTURE)

TRANSPORTHTTPS://YOUTU.BE/5GSGEHT7_ME

GOALS

• COMPARE AND CONTRAST ACTIVE TRANSPORT AND PASSIVE TRANSPORT

• DIFFUSION

• OSMOSIS

• ENDOCYTOSIS

• EXOCYTOSIS

• PHAGOCYTOSIS

• PINOCYTOSIS

PASSIVE TRANSPORT

• NO ENERGY REQUIRED

• MOVE FROM AN AREA THAT IS MORE CONCENTRATED TO LESS CONCENTRATED

• WITH THE CONCENTRATION GRADIENT

• EX: DIFFUSION & OSMOSIS

DIFFUSION

• PARTICLES MOVE FROM MORE CONCENTRATED TO LESS

EQUILIBRIUM

• CONCENTRATION OF THE SOLUTE IS THE SAME THROUGHOUT THE SYSTEM

Equilibrium

OSMOSIS

• DIFFUSION OF WATER THROUGH A SELECTIVELY PERMEABLE MEMBRANE

OSMOSIS

ACTIVE TRANSPORT• ENERGY IS REQUIRED

• MOVE FROM AN AREA THAT IS LESS CONCENTRATED TO MORE CONCENTRATED

• AGAINST THE CONCENTRATION GRADIENT

• EXAMPLES: ENDOCYTOSIS & EXOCYTOSIS

ENDOCYTOSIS• TAKING THINGS INTO THE CELL BY FOLDING THE CELL MEMBRANE

• PHAGOCYTOSIS: EXTENSIONS FROM CYTOPLASM SURROUND A PARTICLE AND PACKAGE IT IN A FOOD VACUOLE. THE CELL THEN ENGULFS IT (THINK OF THE CELL AS EATING IT )

• PINOCYTOSIS: CELLS TAKE IN WATER AND POCKETS FORM IN THE MEMBRANE. THEY PINCH OFF TO FORM VACUOLES IN THE CELL.

EXOCYTOSIS

• MEMBRANE OF A VACUOLE STICKS TO CELL MEMBRANE AND FORCES THE CONTENTS OUT OF THE CELL

ENDOCYTOSIS VS. EXOCYTOSIS