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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