CELLS & the CELLS & the ORGANELLESORGANELLES

Prokaryote vs. EukaryoteProkaryote vs. Eukaryote

Animal vs. PlantAnimal vs. Plant

Cells

“Life is Organized”

Atoms

C,H,N,O,P,S

Molecules

Organelles

Cells

Tissues

Organs

Organ Systems

Organism

Species

Population

Community

Ecosystem

Biome

Ex: Tundra, desert, temperate forest

Biosphere

Smallest / most simple

Largest / most complex

Early MicroscopesEarly Microscopes

• Robert Hooke (1665)

Coined the term “cell” (Why?)

looking at cork, he saw little boxes

Is cork alive?

• Anton von Leeuwenhoek (1674)

saw living cells in pond water

Cells

Cell DiscoveriesCell Discoveries

• Matthias Schleiden (1838) Plants are made of cells

• Theodor Schwann (1839)Animals are made of cells

• Rudolf Virchow (1855) Saw dividing cells new living cells come from

pre-existing cellsCells

The Cell Theory

1. All living things made of cells.

2. Cell are the basic unit of structure & function for life.

3. Cells can only arise from pre-existing living cells

Cells

Types of Organisms

• Unicellular organisms living organisms that are composed of only ONE cell– Examples: bacteria, algae, protists, yeast

• Multicellular organisms any organism that is made of MORE THAN ONE cell– Evolved later

Cells

Prokaryote vs. EukaryoteProkaryote vs. Eukaryote

• Prokaryotic Cells– DNA not bound by a

membrane… no “true nucleus”

– Usually smaller, simple• Nearly all unicellular

– No membrane bound parts (organelles)

• Ex: bacteria– Read Section 6.3

• Eukaryotic Cells– DNA is bound by a

membrane bound nucleus

– Larger, complex, has internal organization

– Have internal membrane bound structures = organelles

• Ex: you, plants, algae

https://www.youtube.com/watch?v=WRO-DPyB9Bk

Cells

Basic Structures For ALL Cells

• Cell membrane– Surround the cell – barrier

between inside and environment

• Cytoplasm– Contains water and

organelles

• DNA– Instructions for the cell to

carry out

• Ribosomes– Makes proteins

Cells

OrganellesOrganelles• Very small size

• Have specific functions

– Create specificity of cells

• EX: muscle cells have more mitochondria than skin cells

• Found throughout cytoplasm

• Examples:

– Nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria, chloroplasts (plants only), vacuoles, cytoskeleton, centrioles (Animal only)

Cells

Cells

Cells

The Nucleus:Control center of the cell, houses genetic material

Cells

Nucleolus• Is a small Is a small

dense region dense region in the nucleusin the nucleus

• Makes Makes ribosomesribosomes, , which make which make proteinsproteins

Cells

RIBOSOMES

• Free floating in cytoplasm

or• Attached to ER

• “reads” RNA code from DNA to assemble proteins

• “protein factory”

Cells

ENDOPLASMIC RETICULUM

• Internal passageway within the cell

• Can be “Rough” or Smooth – Rough has ribosomes

attached protein synthesis

– Smooth has no ribosomes membrane lipid synthesis, detoxification, cholesterol metabolism

Cells

GOLGI APPARATUS• Modifies, sorts,

packages proteins coming from ER

• Destination of products– storage in cell– export out of cell

• Customizes– Adds lipids, carbs to

proteins

Cells

LYSOSOMES• Small, enzyme-filled organelles• Digests material for use or disposal

– Only common in animals but recent evidence suggest they are in plants as well

Cells

MITOCHONDRIA

• Convert food into usable energy

• Have an outer & inner membrane

• Has its own DNA!– Inherited from your

mom

Cells

CHLOROPLASTS• Capture sunlight & convert

it to energy– Photosynthesis – make their

own food– Green plants and some algae

• Have 2 membranes

• Contain the green pigment chlorophyll

• Has its own DNA!

Cells

VACUOLES

• Stores materials

• Water, salts, protein, carbs

• Largest in plants– Gives turgor pressure

• Larger in plants

Cells

CYTOSKELETON• Structural support

& transport

MICROFILAMENTS

Actin – threadlike protein

MICROTUBULES

Tubulins – protein

basis of cilia & flagellaCells

CENTRIOLES

• Help in the process of cell division

• Only in Animals

Cells

PLANTS V. ANIMALS

• CELL WALLS made of cellulose

• LARGER VACUOLE• CHLOROPLASTS

• CENTRIOLES• Smaller or No vacuoles

Cells

Colonies

Cells

ChlamydomonasChlamydomonasVolvoxVolvox

• Volvox is a colony of individual cells.• Each cell of a Volvox resembles a Chlamydomonas (a one-celled organism). •Volvox cells coordinate the beating of their flagella so that the movement is not random through water. - shows cooperation among cells

Colonies – a group of unicellular microorganisms living togetherIf colony attaches to a solid surface = biofilm

VSVS

Colonies of Bacteria

Cells

Cell to Cell Connections• Cells in same tissue communicate with each

other through junctions– Tight junction : membranes are fused, stitched

together; no passage

– Desmosomes: protein fibers that anchor in cytoplasm of neighboring cells

• – allow passage of materials

– Gap junction : Channels formed by donut-shaped proteins btwn cells ; yes passage

– Pits & Plasmodesmata : (plants) cell walls perforated with pits, strands of cytoplasm (plasmodesmata) run through pits connecting cells

Cells

Cells

Cell to Cell Connections

Cells

Extracellular Matrix• Solution of macromolecules

(proteins & carbs) that surround cells in a tissue– Secreted by the cell itself

to the space outside• Holds cells together• Allows them to migrate &

interact• May regulate behavior in

cells– Ex: collagen

Cells

Cells

Division of Labor Division of Labor In In Multicellular Multicellular OrganismsOrganisms

Cells

Tissues – a group of cells working together

Organs – a group of tissues working together

Organ System – a group of organs working together

Organism – a group of organ systems working together

Differentiation – when cells take on a specific role