Cells - 2014Cells - 2014

Structure and Function

By the end of this chapter I must By the end of this chapter I must know>>>>know>>>>

What are the parts to the cell theory and 2 exceptions to the cell theory.

What are the organelles and functions of the organelles in a Animal cell? Plant Cell? A Basic Prokaryotic Cell?

What are the structural differences between a Eukaryotic and Prokaryotic cell?

What are the structural differences between a Plant and Animal cell?

What is the Secretory pathway?**** Can I draw/diagram a plant, animal, and bacterial cell with all

the proper organelles

VocabularyVocabulary

Prokaryote (ic) Eukaryote (ic) Cell Theory Organelle cytoplasm Nucleus Nucleolus Cell membrane Nuclear envelope Chromatin Ribosome Endoplasmic reticulum

– Smooth– Rough

Golgi Apparatus Mitochondria Chloroplast Cell wall Vacuole Lysosome peroxisome Centriole Cytoskelton Slime capsule Mesosome Plasmid Naked DNA

Section 1: Introduction to the CellSection 1: Introduction to the Cell

Figure 3A

Discovery of CellsDiscovery of Cells

The invention of the lens

Robert Hooke (1665): observed a thin slice of cork

(dead plant cells) with a microscope.

observed as “little boxes” (cells).

Discovery of CellsDiscovery of Cells Anton van Leeuwenhoek

(1675): was the first person to observe living cells.

The Cell TheoryThe Cell Theory

Who developed the cell theory?– Matthias Schleiden (1838):

concluded that all plants are composed of cells

– Theodor Schwann (1839): concluded that all animals are composed of cells

– Rudolph Virchow (1855): determined that cells come only from other cells

The Cell TheoryThe Cell Theory

1. All living things are composed of one or more cells.

2. Cells are organisms’ basic units of structure and function.

3. Cells come only from existing cells.

EXCEPTIONSEXCEPTIONS

Skeletal muscles are made of fibers with hundreds of nuclei. Much larger than regular cells.

Bone, blood and cartilage have extracellular material…proteins and fluids.

Mitochondria and chloroplast contain DNA Viruses – have DNA and RNA surrounded

by a protein coat!! NOT classified as a cell!

NeededNeeded Cytological Definitions: Cytological Definitions:

Cell – basic unit of structure and function in a living organism. Organelle – tiny structures in cells with specific functions. Tissue – collection of cells that develop in the same way Organs – groups of tissue that combine to form a single

structure. Organ System – groups of organs that together carry out a

process Autotroph – organism that can make its own food.

(photosynthetic) Heterotroph – organism that cannot make its own food. Differentiate – the ability of multicellular organisms to have

cells that specialize in a certain function.

Cell Diversity- Cell Diversity- SizeSize

Fig. 3.1

CELL SIZECELL SIZE

Remember: (n = nano, μ = micro)• 1μm =.001mm • 1nm = .001μm)

Molecules – 0.5 – 1nm Membranes - 10nm Viruses – 50 – 100 nm Bacteria – 1 – 5 μm Organelles – 5 – 10 μm Cells – 10 – 100 μm

Cell Diversity- SizeCell Diversity- Size

6 inches long, 5 inches wide, 3 pounds

Smallest Cells:

Longest Cells:

Ostrich Egg

Biggest Cells:

Cells and SizesCells and Sizes

Magnification = size of image divided by the size of the specimen

Cell Diversity- ShapeCell Diversity- Shape

Cells differ widely in shape.Most cells are roughly

cuboidal or spherical.

Cells Cells DifferentiateDifferentiate

Differentiation: C

ells within

a multi cellular organism

specialize their function.

Specialized cells have sw

itched on

particular genes (e

xpressed) th

at

correlate to these specialist

functions.

These specific gene expressio

ns

produce particular sh

apes, functions

and adaptations within a cell.

Prokaryotic CellsProkaryotic Cells

Cells Video – You’ll Love this one!!!!

Prokaryotes vs. EukaryotesProkaryotes vs. EukaryotesAN Overview !!AN Overview !!

PROKARYOTIC

LACK membrane bound organelles

Simpler Autotrophs Naked DNA 1-10 microns All bacteria All single-celled First cells to evolve

EUKARYOTIC

HAVE membrane bound organelles

Complex Heterotroph/Autotroph Chromosomes 10-100 microns All other organisms Single / multicellular Evolved from prokaryotes

Prokaryotic Cell

Fig. 3.3.a

Fig. 3.3

Prokaryotic Cell PartsProkaryotic Cell Parts

Cell wall – • Protection and support• Shape• NOT made of cellulose• Made of PEPTIDOGLYCAN

Slime Capsule (encapsulated)• Protection• Not easy to lyse or hydrolyze • Difficult to kill ….pathogenic

Prokaryotic Cell PartsProkaryotic Cell Parts

Plasma membrane• Controls passage of materials

• Selectively permeable (semi permeable)

Flagella– Movement in a liquid environment

Pilli (us)– Hair like projection– Help bacteria stick to its background– Allows 2 bacterial cells to stick together:

conjugation!!

Prokaryotic Cell PartsProkaryotic Cell Parts

Ribosome – protein synthesis

Plasmid – small circular DNA chain. Codes for synthesis of certain proteins. Used in genetic engineering.

Prokaryotic Cell PartsProkaryotic Cell Parts

Ribosome – protein synthesis

Plasmid – small circular DNA chain. Codes for synthesis of certain proteins. Used in genetic engineering.

Prokaryotic Cell PartsProkaryotic Cell Parts Naked DNA – Naked nucleic acid. DNA not

surrounded by a membrane. Carries genetic code. Located in the “nucleoid” region.

Mesosome• Helps in cell division• Increases surface area• In aerobic bacteria: holds respiratory chain• In photosynthetic bacteria: holds photosynthetic pigments.

Fig. 3.3.b

THE PROKARYOTIC CELL

Figure 7.4x2 Figure 7.4x2 E. coli From an Electron MicrographE. coli From an Electron Micrograph

Other Characteristics of ProkaryotesOther Characteristics of Prokaryotes

Form: Form: coccicocci, , bacilli, spirillabacilli, spirilla

Prokaryotic Cells divide by binary Prokaryotic Cells divide by binary fissionfission

Eukaryotic CellsEukaryotic Cells

Fig. 3.4

Fig. 3.4.a

Fig. 3.4.b

ANIMAL PLANT

KNOW HOW TO LOCATE AND BE ABLE TO DRAW AND LABEL…..

The Parts of the CellThe Parts of the Cell

Each living cell carries out the tasks of taking food, transforming food into energy, getting rid of wastes, and reproducing.

Most eukaryotic cells have three main components:– Cell Membrane– Cytoskeleton– Nucleus

Animal CellAnimal Cell

Now let Annotate this picture with all the functions of each structure named

Liver Liver CellCell

Structure and Function of OrganellesStructure and Function of Organelles

Cell MembraneCell Membrane

Structure: – phospholipid bilayer with

proteins that function as channels, markers, and receptors-also contains cholesterol which provides rigidity

Function: – selectively permeable

boundary between the cell and the external environment

Fig. 4.1

NucleusNucleus Structure:

– Similar to cell membrane– Contains nucleolus

Function: -– storage center of cell’s DNA– manages cell functions

Fig. 3.6.b

Inside the NucleusInside the Nucleus

Nuclear Envelope– A double membrane– Porous for movement of protein and ribosomes

Nucleolus– Formation of ribosomes

Chromatin (somes)– Contain DNA and protein– Genetic material

CytoplasmCytoplasm Structure: gelatin-like fluid that lies inside the cell membrane (Watery)

Function: -– Holds all organelle within cytoskeleton– Holds nutrients– Excellent conductor of electricity– Holds dissolved wastes

CytoskeletonCytoskeleton

– Structure: – a network of thin,

fibrous elements made up of microtubules (hollow tubes) AND

– microfilaments (threads made out of actin)

Function: -– acts as a support

system for organelles-maintains cell shape

Fig. 3.12

Fig. 3.12.a1

Fig. 3.12.a2

Fig. 3.12.a3

Fig. 3.12.b1

Fig. 3.12.b2

Fig. 3.12.c1

Fig. 3.12.c2

Fig. 3.13.a

CentriolesCentrioles

Structure: – composed of nine

sets of triplet microtubules arranged in a ring

• Exist in pairs

Function: – centrioles play a

major role in cell division (mitosis)

Area where the centrioles are located: CENTROSOME

Each centrosome: 2 centrioles

Not a part of plant cells.

Fig. 3.13

RibosomesRibosomes

Structure: consist of two subunits made of protein and RNA.

Found alone, in groups (poly) and on rER

Function: location of protein synthesis.

Fig. 3.7.a

The Secretory PathwayThe Secretory Pathway

Endoplasmic ReticulumGolgi Apparatus

LysosomePeroxisome

Endoplasmic ReticulumEndoplasmic Reticulum

Structure: a system of membranous tubes and sacs Function:

– intracellular “highway” (a path along which molecules move from one part of the cell to another)

– Forms transport vesicles

Two types:– Rough Endoplasmic Reticulum – always near

nucleus– Smooth Endoplasmic Reticulum – attached to rER

Fig. 3.7.b

Rough Endoplasmic ReticulumRough Endoplasmic Reticulum

Rough Endoplasmic Reticulum (rER): – prominent in cells that

make large amounts of proteins

– Covered with ribosomes

Smooth Endoplasmic ReticulumSmooth Endoplasmic Reticulum

Smooth Endoplasmic Reticulum (sER): – involved in the synthesis of

lipids and breakdown of toxic substances

– Not covered with ribosomes

Golgi ApparatusGolgi Apparatus Structure: stacked flat sacs Function: receives proteins

from the rER and distributes them to other organelles or out of the cell– collects– sorts– packages – Distributes

LysosomesLysosomes

Structure: spherical organelles that contain hydrolytic enzymes within single membranes

A type of vesicle Function: breaks down

food particles, invading objects, or worn out cell parts

PeroxisomesPeroxisomes

Structure: spherical organelles that contain enzymes within single membranes

A type of vesicle Function: Degrade

hydrogen peroxide, a toxic compound that can be produced during metabolism.

Fig. 3.8

Secretory PathwaySecretory Pathway

rER packages protein into vesicles that separate from ER

Vesicles travel and fuse with Golgi Apparatus

Golgi modifies & repackages protein into new secretory vesicles.

Secretory Vesicles released into cytoplasm

Vesicles fuse with Cell MembraneContents released – SECRETION!

Secretory PathwaySecretory Pathway

Fig. 3.8

MITOCHONDRIA

MitochondriaMitochondria

Structure: folded membrane within an outer membrane– The folds of the inner

membrane are called cristae

Function: -converts energy stored in food into usable energy for work– cellular respiration

Fig. 3.11.a

Fig. 3.9

Cilia and FlagellaCilia and Flagella

Structure: hair-like organelles that extend from the surface of cells– When they are present in large numbers on a

cell they are called cilia– When they are less numerous and longer they

are called flagella– Both organelles are composed of nine pairs of

microtubules arranged around a central pair. Function: cell motility

Cillia and FlagellaCillia and Flagella

PLANT CELLSPLANT CELLS

The other Eukaryotic Cell

Fig. 3.5.b

Fig. 3.5.a

Fig. 3.5.b

Cell WallCell Wall

Structure: rigid wall made up of cellulose, pectin, proteins, and carbohydrates

Function: boundary around the plant cell outside of the cell membrane that provides structure and support

VacuolesVacuoles

Structure: a sac of fluid surrounded by a membrane– Very large in plants

Function: used for temporary storage of wastes, nutrients, and water

ChloroplastsChloroplasts

Structure: stacked sacs (thylakoids) that contain chlorophyll surrounded by a double membrane

Function: photosynthesis (conversion of light energy to chemical energy stored in the bonds of glucose)

Fig. 3.10.a

Structural Organization of Eukaryotic Structural Organization of Eukaryotic and Prokaryotic Cellsand Prokaryotic Cells

Eukaryotes vs. ProkaryotesEukaryotes vs. Prokaryotes

Eukaryotes (animals, plants, fungi, protists) and prokaryotes (bacteria) differ greatly in structure.

Prokaryotes Eukaryotes

nucleus? NO (nucleoid) YES

membrane-bound organelles?

NO YES (Many)

size 1 - 10 m 10 - 50 m

when evolved? 3.5 billion years ago 1.5 billion years ago

cytoplasm? YES YES

cell membrane? YES YES

cell wall? Some Do Plants

ribosomes? YES YES

DNA? CircularFree Floating

Chromosomes in Nucleus

examples Bacteria Plants, Animals, Fungi, and Protists

Plant Cells vs. Animal CellsPlant Cells vs. Animal Cells

Animal cells are very similar to plant cells except for the following major differences:– Animal cells do not contain

chloroplasts– Animal cells are not

surrounded by cell walls– The vacuoles in plants are

much larger than those of animals

Microscope Pictures of aMicroscope Pictures of aPlant Cell and an Animal CellPlant Cell and an Animal Cell

ElodeaElodea Human Cheek CellsHuman Cheek Cells

Cellular Levels of OrganizationCellular Levels of Organization

Cell TissueOrganOrgan SystemOrganism

THE END!THE END!