What is common with every living thing on earth?
I. Development of the Cell Theory
A. Robert Hooke (1600's)- observed cork (dead box-like structures) called cells B. Other Scientists (1800's)- proposed conclusion of the cell which lead to the Cell Theory
A. Robert Hooke (1600's)- observed cork (dead box-like structures) called cells
B. Other Scientists (1800's)- proposed conclusion of the cell which lead to the Cell Theory
CELL THEORY states:
1. All organisms are made of one or more cells. 2. All cells carry on life activities. 3. New cells arise only from other living cells by the process of cell division.
TWO BASIC CELL TYPES
1. Prokaryotic Cells-(means without a nucleus) are single celled organisms that lack internal membrane-bound structures example: bacteria 2. Eukaryotic Cells-(means with a nucleus) are all living things except bacteria; these cells have many internal membrane-bound structures example: nucleus Both use the same life functions, using the same kind of organic compounds.
1. Prokaryotic Cells-(means without a nucleus) are single celled organisms that lack internal membrane-bound structures
example: bacteria
2. Eukaryotic Cells-(means with a nucleus) are all living things except bacteria; these cells have many internal membrane-bound structures
example: nucleus
Both use the same life functions, using the same kind of organic compounds.
CELL SIZE
1. Nutrients must get into the cell and wastes must be removed; what limits this exchange is the cell's surface area-to-volume ratio. 2. Therefore, the smaller the cell the larger the surface area this means more materials can be exchanged with the environment.
Cell Structure
ORGANELLES- (small organs of the cell) specialized internal structures of the cell, examples:
1. Cell Wall- rigid, lies outside cell membrane -contains cellulose -function is to shape, protect & support cell -not found in animals, VIRTUAL CELL 2. Cell Membrane- (plasma membrane) -composed of lipids, proteins & carbohydrates -selective permeability which allows only certain substances to pass through -help maintain homeostasis -Fluid Mosaic Model currently accepted model of the structure of the cell membrane (although research is ongoing in this area)
1. Cell Wall- rigid, lies outside cell membrane
-contains cellulose -function is to shape, protect & support cell -not found in animals, VIRTUAL CELL
2. Cell Membrane- (plasma membrane)
-composed of lipids, proteins & carbohydrates -selective permeability which allows only certain substances to pass through -help maintain homeostasis -Fluid Mosaic Model currently accepted model of the structure of the cell membrane (although research is ongoing in this area)
3. Nucleus- control center (brain of cell) -has nuclear membrane that surrounds nucleus -has nucleolus which are dense granular bodies that are responsible for making ribosomes & RNA -chromatin (DNA) in nucleus which become chromosomes during cell division 4. Cytoplasm- consists mainly of water which allows life processes of cell to occur 5. Endoplasmic Reticulum (ER)- system of fluid filled canals -transport materials within the cell -rough ER has ribosomes on surface -smooth ER does not have ribosomes 6. Golgi Bodies- stacks of flattened membrane sacs -process, package & store products released by cells -aids the ER in making the the cell membrane 7. Lysosomes- small sac-like structures surrounded by single membrane -suicide sacs -contain digestive enzymes -produced by golgi bodies 8. Mitochondria- "power house of cell" MIGHTY MITOCHONDRIA -double layer membrane; inner layer is highly folded for increase surface area -site of cellular respiration (energy released from food) -contain its own DNA 9. Microtubules- long hollow cylindrical structures in cytoplasm -support structure "skeleton of cell" -found in centrioles, cilia, flagella 10. Microfilaments- "muscles of cell" -involved in movement of cytoplasm = CYCLOSIS 11. Centrioles- play role in cell division (mitosis) -in animal cells only lie at right angles 12. Cilia & Flagella- organelles responsible for cell movement 13. Vacuoles- fluid filled sacs (food or contractile) -in animals usually small -in plants usually large 14. Ribosomes- make or synthesize proteins In 1950's, George Palade discovered ribosomes & the function of the endoplasmic reticulum. 15. Plastids- these organelles are found only in plant cells 2 types of plastids -leukoplasts = store starch -chloroplasts = sites for photosynthesis & has green chlorophyll pigment, also has its own DNA in chloroplasts: 1. Grana- membrane stacks of thylakoids for photosynthesis 2. Stroma- material that fills rest of chloroplasts
3. Nucleus- control center (brain of cell)
-has nuclear membrane that surrounds nucleus -has nucleolus which are dense granular bodies that are responsible for making ribosomes & RNA -chromatin (DNA) in nucleus which become chromosomes during cell division
4. Cytoplasm- consists mainly of water which allows life processes of cell to occur
5. Endoplasmic Reticulum (ER)- system of fluid filled canals
-transport materials within the cell -rough ER has ribosomes on surface -smooth ER does not have ribosomes
6. Golgi Bodies- stacks of flattened membrane sacs
-process, package & store products released by cells -aids the ER in making the the cell membrane
7. Lysosomes- small sac-like structures surrounded by single membrane
-suicide sacs -contain digestive enzymes -produced by golgi bodies
8. Mitochondria- "power house of cell" MIGHTY MITOCHONDRIA
-double layer membrane; inner layer is highly folded for increase surface area -site of cellular respiration (energy released from food) -contain its own DNA
9. Microtubules- long hollow cylindrical structures in cytoplasm
-support structure "skeleton of cell" -found in centrioles, cilia, flagella
10. Microfilaments- "muscles of cell"
-involved in movement of cytoplasm = CYCLOSIS
11. Centrioles- play role in cell division (mitosis)
-in animal cells only lie at right angles
12. Cilia & Flagella- organelles responsible for cell movement
13. Vacuoles- fluid filled sacs (food or contractile)
-in animals usually small -in plants usually large
14. Ribosomes- make or synthesize proteins
In 1950's, George Palade discovered ribosomes & the function of the endoplasmic reticulum.
15. Plastids- these organelles are found only in plant cells
2 types of plastids -leukoplasts = store starch -chloroplasts = sites for photosynthesis & has green chlorophyll pigment, also has its own DNA in chloroplasts: 1. Grana- membrane stacks of thylakoids for photosynthesis 2. Stroma- material that fills rest of chloroplasts
2 types of plastids
-leukoplasts = store starch -chloroplasts = sites for photosynthesis & has green chlorophyll pigment, also has its own DNA in chloroplasts: 1. Grana- membrane stacks of thylakoids for photosynthesis 2. Stroma- material that fills rest of chloroplasts
-leukoplasts = store starch
-chloroplasts = sites for photosynthesis & has green chlorophyll pigment, also has its own DNA
in chloroplasts: 1. Grana- membrane stacks of thylakoids for photosynthesis 2. Stroma- material that fills rest of chloroplasts
MAINTAING CELLULAR HOMEOSTASIS
1. Passive Transport- NO cell energy is used a. Diffusion- movement of molecules from area of high concentration to an area of low concentration Concentration Gradient- difference between areas of high + low concentrations [*diffusion only occurs if there is a gradient*] Equilibrium- molecules are evenly distributed b. Facilitated Diffusion- specialized transport proteins speed up diffusion -unlike enzyme does not cause chemical reaction ex) glucose from blood transported into cell c. Osmosis- diffusion of "water" through a selectively permeable membrane -Osmotic Pressure: increased pressure on cell membrane due to osmosis
1. Passive Transport- NO cell energy is used
a. Diffusion- movement of molecules from area of high concentration to an area of low concentration Concentration Gradient- difference between areas of high + low concentrations [*diffusion only occurs if there is a gradient*] Equilibrium- molecules are evenly distributed b. Facilitated Diffusion- specialized transport proteins speed up diffusion -unlike enzyme does not cause chemical reaction ex) glucose from blood transported into cell c. Osmosis- diffusion of "water" through a selectively permeable membrane -Osmotic Pressure: increased pressure on cell membrane due to osmosis
a. Diffusion- movement of molecules from area of high concentration to an area of low concentration
Concentration Gradient- difference between areas of high + low concentrations [*diffusion only occurs if there is a gradient*] Equilibrium- molecules are evenly distributed
Concentration Gradient- difference between areas of high + low concentrations [*diffusion only occurs if there is a gradient*]
Equilibrium- molecules are evenly distributed
b. Facilitated Diffusion- specialized transport proteins speed up diffusion
-unlike enzyme does not cause chemical reaction ex) glucose from blood transported into cell
c. Osmosis- diffusion of "water" through a selectively permeable membrane
-Osmotic Pressure: increased pressure on cell membrane due to osmosis
ISOTONIC SOLUTION: a solution that contains the same concentration of dissolved substances as does a living cell place in it
HYPOTONIC SOLUTION: a solution that contains a lower concentration of dissolved substances than inside the cell ex) cells gain water and swell; animal cells burst (place a salt water fish in freshwater), plant cells gain tugor
HYPERTONIC SOLUTION: greater concentration of dissolved substances than inside the cell ex) cells lose water and shrink
2. Active Transport- require cell energy (ATP) -materials move against the concentrated gradient a. Endocytosis- process of moving materials into a cell by means of a vesicle (1) Pinocytosis- liquids are taken into the cell (2) Phagocytosis- the process in which (solid) particles or small organisms are ingested into a cell b. Exocytosis- reverse of endocytosis; movement of materials out of the cell
2. Active Transport- require cell energy (ATP) -materials move against the concentrated gradient a. Endocytosis- process of moving materials into a cell by means of a vesicle (1) Pinocytosis- liquids are taken into the cell (2) Phagocytosis- the process in which (solid) particles or small organisms are ingested into a cell
b. Exocytosis- reverse of endocytosis; movement of materials out of the cell
LEVELS of ORGANIZATION
Organelle Interactive Quizzes
Cells Interactive Quizzes
Biology Trivia
1. The cellular function of the endoplasmic reticulum is to...
provide channels for the transport of materials convert urea into a form usable by the cell regulate all cell activities change light energy into chemical bond energy
2. In which organelles are polypeptide chains synthesized?
nuclei vacuoles ribosomes cilia
3. Which organelle contains hereditary factors & controls most cell activities?
nucleus cell membrane vacuole endoplasmic reticulum
4. Centrioles are cell structures involved primarily in...
cellular respiration cell division storage of fats enzyme production
5. In which organelle of a spinach cell, would most of the pigments be found?
centrioles nucleus chloroplast mitochondria
6. Which organisms normally use contractile vacuoles to help maintain water balance?
freshwater protozoans saltwater bacteria terrestrial mammals desert plants
7. The presence of hydrolytic enzymes is most closely associated with the cell organelles known as...
contractile vacuoles plastids lysosomes Golgi bodies
8. Which statement is not part of the cell theory?
Cells are the structural units in living things. Cells are the functional units in living things. New cells areis from preexisting cells. New cells have nuclei idetical to those of preexisting cells.
9. What is the largest cell in the world?
an ameba an ostrich egg a human fetus a whale's egg
10. What two organelles are considered to be exceptions to the cell theory because they contain their own DNA?
microfilaments & microtubules mitochondria & chloroplasts Golgi bodies & ribosomes lysosomes & centrioles return to Mr. Buono's syllabus
microfilaments & microtubules mitochondria & chloroplasts Golgi bodies & ribosomes lysosomes & centrioles
return to Mr. Buono's syllabus