Cell- smallest unit of matter that is capable of performing the characteristics and function defined as life
A. Cell Theory-
нн 1. All life is composed of cells
нн 2. All cells are the basic organizational unit of life
нн 3. Allн cells come from other cells
B. Early Scientistsнн
1. Robert Hooke (1665)- first to describe a "cell". Used cork to identify tiny individual boxes
нн 2. Antonie van Leeuwenhoek (1673)- identified microorganisms in pond water; basic cellular structure
нн 3. Matthias Schleiden ( 1838) - stated that plants are multicellular organisms
нн 4. Theodor Schwann (1839)- stated animals are multicellular organisms
нн 5. Rudolf Virchow (1855)- examined cell reproduction in lower organisms
C. Regions of the cell
нн 1. Cell membrane- the outer barrier of the cell
ннннннн * regulates the passage of molecules in and out of the cell
нн 2. Cytoplasm - semi fluid medium and components inside the cell
нннн a. organelles- small bodies within the cytoplasm which have individualized structures and functions
нннн b. cytosol- semi- fluid medium of dissolved organic matter which supports the organelles
нн 3. Nucleus - specialized organelle which contains the genetic matter
D.н Types of Cells
1. Prokaryotic - "pre-nucleus" cell; doesn't contain a distinct nucleus
нннн - nucleoid region - region in cytoplasm where genetic information is found
нннн * Found primarily in the Monera Kingdom- Bacteria
2. Eukaryotic- "true" nucleus' contains a distinct nucleus with nuclear membrane
нннн - most forms of life contain eukaryotic cells
** Reference to cells will pertain to eukaryotic cell unless mentioned
E. Parts of the Cell
1. Cell membrane (Plasma membrane)н - fluid medium with the consistency of oil
нннн a. Components:
1. Phospholipid bilayer: н Two layers oriented so non-polar tails point inward -- forming
hydrophobic bonds
ннннннннн * Glycolipids are occasionally found in the outer layer in the place of the phospholipids
нннннннннннн glycolipids- fat with two fatty acid chains and 1 sugar chain where the phosphate is usually found
ннннннн нннн purpose- cell to cell recognition; different cells have different glycolipidsннннн
2. Cholesterol: found in one layer which lends to stability of the lipid layer:н keeps the membrane
fluid at lower temperatures
ннннннн 3. Proteins: either span the bilayer or found embedded in one single layer
ннннннннн a. transport- transports most molecules in and out of the cell
нннннннннннн i.н channel - allows for straight passage of molecules or ions
нннннннннннн ii. carrierн -н bonds with molecules or ions to facilitate passage
нн b. cell recognition
нннннннннннн i.н glycoprotein- finger prints the cell because of the sugar chain attached
c. receptor protein- has specific shape to bond with certain molecules (hormones) which cause a
certain chemical reaction within the cell
d. cell adhesion - bonds particular cells together
e. attachment - bonds filaments of the cytoplasm to the cell membrane
нн f.н enzymatic- perform chemical reactions with membrane and cytoplasm
нн g. more of which have to be explored (?)
нннн
b. Fluid- Mosaic Model - term used to describe the appearance and function of the cell membrane
ннннннн 1. phospholipids, glycolipids and cholesterol all assist in producing a fluid characteristic
нннннннннннн - molecules can move...
ннннннн 2. proteins, glycolipids and cholesterol give the mosaic pattern
c.н Membrane characteristics
ннннннн 1. selectively permeable- characteristic where membrane regulates the passage of particles
ннннннннн a. diffusion- movement of particles from an area of higher concentration to an
ннннннн нннн area of lower concentration. net movement- movement which changes concentrations
нннн b. factors that affect diffusion
нннннннннннн i. particle size and shape
нннннннннннн ii. temperature
нннннннннннн iii. concentration gradient- difference in concentrations
нннннннннннн iv. cytoplasmic streaming- continuous movement of materials in cytoplasm
d. diffusion in membranes
ннннннн 1. facilitated diffusion- using a protein to move particles down the conc. gradient
ннннннн 2. active transport- using a protein to move particles up the conc. gradient
ннннннннн *requires energy -н ATP - adenosine triphosphate
pump- proteins that use active transport to move particles between interior and exterior of cell
3. osmosis - diffusion of water across a selectively permeable membrane
- water moves from an area of high water conc.(low solute) to an area of low water conc. (high solute)ннн
нн ннннннн -osmotic pressure - internal pressure due to net movement of water into
ннннннн 4. osmotic conditions: cell concentration vs. environmental solution conc.
ннннннннн a. isotonic- solute conc. inside is the same as outside-- no net movementн of water
нннннннннннн нн animal cell ё normal ннннннннннннн plant cell -н flaccid
ннннннннн b. hypotonic- solute conc. outside is less than cell conc.
нннннннннннннн animal cell- lysedннннннннннннн plant cellнн - turgid
ннннннннн c. hypertonic- solute conc. outside is greater than cell conc.
нннннннннннннн animal cell ё crenatedн ннннннн plant cell -нн plasmolyzed
нннн
e movement of particles larger than transport proteins
нн 1. endocytosis- cell membrane indents around molecules and forms a vesicle
нннн н нн нa. pinocytosis- uptaking fluid molecules
нннн н нн нb. phagocytosis- uptaking solid molecules
нн 2. exocytosis- vesicles fuse with cell membrane and release materials
2. Cytoplasm- the region of the cell inside the cell membrane
a. cytosol- solution
ннннннн - contains amino acids, monosaccharides, water and other essential molecules
ннннннн (All basic building blocks for the macromolecules)
нннн b. Organelles -
membraned bodies housed within the cell: Each has a specialized design and
function
нн 1. Ribsome- organelle having 2 subunits made from proteins which function to produce proteins
ннннннннн a. "free"- found suspended in cytosol
ннннннннн b.
"bound"- found attached to endoplasmic reticulum
нннн Membranous canals and vacuoles
ннннннн 2. Endoplasmic reticulum- membraned canals that connect the nucleus with the cell membraneн
ннннннннн a. "rough" - contains ribosomes on outer membrane surface
нннннннннннн - responsible for assistance in protein synthesis and transport to exterior of the cell
ннннннннн b. "smooth" - no ribosomes; but contains specialized enzymes
нннннннннннн -various functions depending upon location in the body
нннннннннннн -lipid synthesis, carbohydrate metabolism, detoxification of drugs
ннннннн 3. Golgi Apparatus- similar in appearance to smooth E.R.
ннннннннн - works in conjunction with the E.R. where it modifies, stores and routes products of the E.R. н н
нннннн нн - uses vesicles to transport molecules between E.R., Golgi and other parts
4. vesicle- membrane storage compartment used in endo & exocytosis mechanism
ннннннн 5. Vacuole- membraned organelle used primarily for storage
ннннннннн a. food vacuoles - store food for reserve usage's
ннннннннн b. contractile vacuole- stores water and pumps out excess when necessary
ннннннннн c. central vacuole- plant vacuole which has a variety of functions
нннннннннннн - stores molecules, deposit for metabolism by-products, contain pigments
ннннннн 6. Lysosomes- "suicide organelles"- membrane bound organelles that contain enzymes whose
responsibilities are macromolecule and organelle digestion
ннннннннн - formed from the Golgi apparatus
нн нн Energy-related organelles
ннннннн 7.н Mitochondria- double membraned organelle that is responsible for respiration
ннннннн 8. Plastid- organelle found in plants that are responsible for food production (carbohydrates)
- chloroplasts- plastids which contain chlorophyll
3.н Cytoskeleton- scaffolding structure of the cytoplasm (mesh netting)
ннннннн - maintains cell's shape, anchors organelles, allows cell and contents to move within cell
нннн a. consists of 3 different protein tubules
ннннннн 1. microtubules- largest- usually in the form ofн cilia and flagella & also moves organelles
ннннннн 2. intermediate filaments- assistance in cell division ( cleavage furrow)
ннннннн 3. microfilaments- smallest- assists in support of the cell
4. Nucleus
нннн - double membraned organelle which contains chromosomal material
a. Components
1. nuclear envelope ( membrane)- double membrane which surrounds the nucleus & is continuous
with the endoplasmic reticulum
-nuclear pores- holes in the envelope formed from embedded protein which allow certain molecules to pass from cytoplasm to nucleoplasm
ннннннн 2. nucleolus- dense area which function in the synthesis of ribosomesнннн
нннн нн 3. chromatin- regions where genetic material is found
нннннннннннн - long chains of DNA molecules -- Deoxyribonucleic acids
нннннннннннн -chromosome - condensed chromatin
F. Cell Division & Mitosis
нн 1. DNA replication- production of identical DNA double helices
a. Binary Fission- (Asexual reproduction)-н Prokaryotic organisms
b. Eukaryotic cell division (Asexual repro of single-celled Eukaryotes)
1. chromosome structure
a. chromatin- н histoneн
b. chromosome
-homologous chromosome- нн centromere
нннннннннннн -kinetochore
нннннннннннн -sister chromatids
-karyotype- 46 chromosomes- 23 pairs
c. Cell Cycle
1. parent cell
2. daughter cell
3. 5 phases:нннн G1§ S § G2 § M § C
Interphaseн (G1 § S §G2)
нннннннннннн a. G1 - (Primary Growth Phase) a.k.a. (G = gap)
нннннннннннн b. S - нн (Genome Synthesis, DNA replication)
нннннннннннн c. G2 - (Secondary Growth Phase)
нннннннннннн d.н M- (Mitosis) - 4 stages
i. prophase-н centrioles, poles, spindle fibers, asters
ii. metaphase-н equator (metaphase plate)
iii. anaphase
iv. telophase
v. Cytokinesis ( C)нннннннннннннннн
ннннннннннннннннннн -animal cells- cleavage furrow
ннннннннннннннннннн -plant cells - cell plate
**The 5 phases are sometimes condensed to IPMAT, where interphase is the time between daughter cell formations.