the cell cell theory/history structures transport differentiation levels of organization
TRANSCRIPT
The CellThe CellCell Theory/HistoryCell Theory/HistoryStructuresStructuresTransport Transport Differentiation Differentiation Levels of Organization Levels of Organization
Robert Hooke
• English physicist• 1665• Saw a slice of
cork tree tissue– Tiny chambers– Termed them
“cells”(looked like monks’ cells in monastery)
Robert Hooke
• Published his book Micrographia– Contained
drawings of cork cells
– Used early microscope
Anton Van Leeuwenhoek
• Dutch businessman
• 1674• Perfected
microscope(about 300x)
• Saw living things in pond water– “Animalcules”– Observed
bacteria (on wood teeth) and protozoa
Matthias Schleiden
• German botanist
• 1838• Concludes that
all plants are made up of cells
Theodor Schwann
• German zoologist
• 1839• Concluded that
all animals are made up of cells
Rudolph Virchow
• German physician/pathologist
• 1855• Worked with eggs
from various organisms
• Proposes that all cells come from existing 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.
Janet Plowe
• 1931• Demonstrates that the cell
membrane is a physical structure, not an interface between two liquids.
Lynn Margulis
• 1970• Proposes a
theory that certain organelles were once free-living cells themselves
Singer - Nicholson
• 1972• Fluid Mosaic Model
– Membranes are phospholipid bilayers with globular proteins embedded in them
– Membrane is always moving– Made up of smaller pieces
(mosaic)
Barriers…
Cell WallPlants & prok. (not animals)Structural (plant support) & protective roleCelluloseFreely permeable
Barriers…
Cell Membrane (plasma membrane)In ALL cellsSupport/protection Regulates movement in/out of:
○ Water○ Nutrients○ Waste products
Barriers…
Nuclear Envelope (nuclear membrane)Surrounds nucleusThousands of pores
○ Material move in/out, incl. RNA
Fluids…
Cytoplasm (cytosol)Bet. cell mem. and nuclear env.,
site of most chemical activity
NucleoplasmSemi-fluid medium of nucleus
ProtoplasmTerm used for all substances inside cell
The Nucleus…
Controls most cell processes Contains Chromatin
DNA bound to proteinsDuring cell division, condenses to
Chromosomes…
Has a NucleolusSmall, dense regionAssembly of Ribosomes
Nuclear Envelope (or membrane)
Endoplasmic Reticulum… Called “ER” Two types:
Rough ER○ Ribosomes stud surface○ Aids in synthesis and modif. of proteins○ Found wrapped around nucleus
Smooth ER○ No ribosomes○ Special tasks with certain enzymes
(such as making lipids)
Mitochondrion…
Uses energy from food Makes high-energy compounds (ATP)
needed for Rx elsewhere. The POWERHOUSE of the cell
Golgi Apparatus…
Receives proteins from rough ER Enzymes attach carbs and lipids to the
proteins Can store proteins until needed Proteins then sent to final destination PACKAGING and SHIPPING
Vacuoles…
Saclike structure Stores water, salts, proteins, carbs Can be large in plant cells
Helps in plant support by keeping turgor pressure high
Vacuoles
Korotnovella, an amoeba. Inside this cell we can see a nucleus near the center with a rather angular dark nucleolus, various food vacuoles, and a clear round contractile vacuole at about 10 o'clock.
Lysosomes…
Filled with enzymes Breaks down
lipids, carbs, and proteins from foodold organellesdebris and harmful invaders
Plastid 1: Chloroplasts…
In plants, not animals or fungi Uses sunlight to make energy rich food
mol. thru photosynthesis
Centrioles
Cylindrical; group of microtubules In animal cells, used in cell division As “basal bodies,” form cilia and flagella
The Cell Membrane
Is composed of a phospholipid bilayer
A barrier; reg. what passes in/out Supports and protects Selectively permeable – only certain things pass through. About 5 nanometers thick (1 nm = 1 Billionth of a meter)
Cell membrane - Structure
A phospholipid contains-
one head; negatively charged phosphate group that is hydrophilic (water-loving)
two tails of fatty acid chains that are hydrophobic (water fearing)
Cell membrane features
The fluid mosaic modelit is fluid in nature allowing cell mobilityScattered in the membrane are various
proteins which perform various functions:
○ enzyme activity,○ cell attachment,○ communicating with other cells, ○ Trans. of substances in and out
Passive transportDiffusion: net movement of sub. (liquid or gas) from an area
of higher conc. to area of lower conc. Example: perfume
Passive transportOsmosis: diffusion of water across a
semi-permeable or selectively perm. membrane.○ Hypertonic: Solution having a high conc. of solute. ○ Hypotonic: Solution having a low conc. of solute. ○ Isotonic: Both solutions have equal solute conc.
○ This difference (Δ) of conc. of molecules across a space is called a Concentration Gradient
Passive transport
Facilitated diffusion = trans. of materials across membranes by transport proteins
Active transport
Active transport - Trans. of molecules against a concentration gradient (from regions of low conc. to regions of high conc.) with the aid of proteins in the cell mem. and energy from ATP
Other types of active transport Other types of active transport
Endocytosis – import of materials into cell by infoldings of the cell membrane. A. phagocytosis – “cell eating”; extensions of the cell membrane surround the food and make a vacuole. Lysosomes then secrete enzymes into vacuole to digest food.B. pinocytosis – “cell drinking”; smaller infoldings allowing droplets of liquid to enter cell.
Exocytosis – reverse of endocytosisDumping of excretions or wastes outside by
discharging them from waste vacuoles.Also can result in secretion of substances
(ex: gland cells secreting hormones into the bloodstream)
Cell differentiation
The process by which unspecialized cells develop into their mature forms and functions
Embryonic Stem CellsUndifferentiated (unspecialized)
○ Totipotent – can develop into ANY type tissue
Adult Stem Cells○ Pluripotent or multipotent – can develop into
certain types of tissues.
Levels of organization
Level one = cells -basic unit of life; examples are blood cells
○ Red (RBC, or erythrocytes)○ White (leukocytes)
nerve cells (neurons),bone cells (osteoblasts)
Levels of organization Level two -tissues= Made up of cells that are similar in
structure and function and which work together to perform a specific activity
-Humans have 4 basic tissues: connective, epithelial, muscle, and nerve. Connective tissue
○ include bones, ligaments, cartilage, blood, tendonsEpithelial tissue-
○ skin, the mucosa, and the serosa (lines body cavities and internal organs)
Muscle tissue-○ skeletal muscle, smooth muscle, and cardiac muscle
Nerve tissue- ○ brain, spinal cord, and nerves
Levels of organization
LEVEL 3 – Organs -Made up of tissues that work together to perform a specific activity heart, brain, skin, etc.
LEVEL4 - Organ Systems -Groups of two or more organs that work together to perform a specific function for the organism.The Human body has 11 organ systems - circulatory,
digestive, endocrine (hormonal), excretory (urinary), lymphatic (immune), integumentary (skin), muscular, nervous, reproductive, respiratory, and skeletal.
Levels of organization
LEVEL 5 - Organisms -Entire living things that can carry out all basic life processes.
Meaning they can take in materials, release energy from food, release wastes, grow, respond to the environment, and reproduce.
Usually made up of organ systems, but an organism may be made up of only one cell such as bacteria or protist.
Examples - bacteria, amoeba, mushroom, sunflower, human
Cell Regulation
What makes a cell divide?Internal signal: Enzymes produced by cellExt. signal: like growth factor produced
elsewhereWhen cells packed close, NO divisionNot packed, division starts
Checkpoints: where stop/go signals reg. division
Uncontrolled division
Too many cells form a tumorDisrupts normal
cell activityTakes nutrientsIf one area only:
benignIf spreading:
malignant
The staging of a carcinoma has to do with the size of the tumor, and the degree to which it has penetrated. When the tumor is small and has not penetrated the mucosal layer, it is said to be stage I cancer. Stage II tumors are into the muscle wall, and stage III involves nearby lymph nodes. The rare stage IV cancer has spread (metastasized) to remote organs.
http://www.nytimes.com/imagepages/2007/08/01/health/adam/19222Stagesofcancer.html