Download Cell structure teacher notes PreAP 14-15

Characteristics of Life and Levels of Organization Notes
8 Characteristics of Life: Organism must have all 8 to be considered living.
Read Chapter 1 p. 16-19 and determine the 8 characteristics of life. List the characteristics below
highlighting the key words in each definition.
1. Made of cells
2. Adapt and respond to environment
3. Homeostasis or internal balance
4. Has genetic code—DNA and/or RNA
5. Evolve over time
Add questions or TAKE
5’s to ppt:
Could there be
multicellular prokaryotes?
Order of protein
processing and production.
6. Consume energy
7.
Reproduce
8. Grow and develop
Levels of Organization:
Place the following levels in order from largest to smallest: Cells, Tissue, Organ, Organ System, Organism
Give an example for each using yourself as the organism and working your way down to cells
Ex: Organism – Jeremy Lin down to Cell—stomach muscle cell
1. Cell—stomach muscle cell
2. Tissue—stomach muscle
3. Organ—stomach
4. Organ system—digestive system
5. Organism—Jeremy Lin
Cell Structure and Function Notes
Discovery of the Cell:
 Mid 1600’s scientists began using microscopes to observe living things

Robert Hooke used microscope to observe thin slice of cork—dead plant material
Cork seemed to be made of box-like chambers—Hooke called cells

Anton van Leeuwenhoek discovered living cells in pond water
Cell Theory:
 All living things composed of cells

Cells are the basic unit of structure and function in living things

New cells are produced from existing cells
Cell and its Environment:
 Organisms made of one cell—unicellular organisms
Ex: bacteria

Organisms made of many cells—multicellular organisms
Ex: plants, animals

Each cell must be in “balance” with its environment, exchange food, waste, H2O, CO2, O2 etc.

Process by which organisms maintain a relatively stable internal environment—homeostasis
Cell:


Organisms that do not have a distinct nucleus—prokaryotic (PRO = BEFORE)
Ex: bacteria
Organisms with cells that have true nucleus and organelles—eukaryotic (EU = TRUE)
Ex: plants, animals, fungi
Cell Parts and Their Functions:
Specialized cell parts called organelles—“little organs”
1. Cell membrane—determines what goes in and out of the cell
2. Cytoplasm—gel-like medium that holds the organelles in position
3. Nucleus—control center of the cell

Double membrane that surrounds the nucleus—nuclear envelope

Hereditary information inside the nucleus—chromatin (DNA)

Site where ribosomes are made--nucleolus
4. Ribosomes—makes proteins
5. Rough Endoplasmic Reticulum (rough ER)—makes and transports proteins within the cell

Called rough ER because of the ribosomes found on its surface
6. Smooth Endoplasmic Reticulum (smooth ER)—makes and transport lipids and other materials
within the cell

Called smooth ER because no ribosomes found on its surface
7. Cytoskeleton—network of protein filaments that helps cell maintain its shape
8. Golgi apparatus—processes and packages proteins and other substances produced in the ER

Golgi apparatus prepares these substances either to be stored in the cell or secreted
outside the cell in membrane bound vesicles
9. Mitochondria—supplies energy to the cell (powerhouse)
10. Vacuoles—sac-like structures for storage of materials such as water, salts, proteins and carbs

Plant cells usually contain a large vacuole that fills most of the cell—pressure from this
large vacuole helps plants support themselves
Found in animal cells only:
11. Lysosomes—cleans up the cell and digests unwanted materials, contains digestive enzymes
Found in plant cells only:
12. Cell wall—provides support and protection for cell

Composed mainly of cellulose (plant starch)—fiber for our diet
13. Chloroplast—makes glucose using the energy from the sun (photosynthesis)
Specialized Parts for movement:
1. Cilia (like little hairs)
2. Flagella (like a tail)
Specialized Cells:
Different cells in your body do different jobs. The structure (how it’s built) of cells matches the
function (what it does).

Plant Examples:
1. Leaf cell—contains many chloroplasts to maximize photosynthesis
2. Root cell (potato)—contains many vacuoles to maximize water and starch storage

Animal Examples:
1. Epithelial cells—have villi to increase nutrient absorption; found in the intestines
2. Muscle cells—contain many mitochondria to produce more energy for movement
3. Nerve cells—have fibers called dendrites that allow nerve cells to communicate with each other
Cell Membrane: (text p. 182)
1. ALL cells have a cell membrane
2. Cell membranes are selectively permeable


control what enters and leaves the cell
not solid, but fluid—always in motion (soap bubbles)
3. Composition – lipids and proteins

Phospholipid bilayer—small molecules can pass through
ex: O2, CO2, H20, alcohol

Proteins—embedded in lipids, allows for passage of large molecules through lipid bilayer
a. marker protein – has a unique carbohydrate chain to identify the cell – how organ
donors and recipients are matched
b. protein channel – allows larger molecules needed by the cell to pass through the cell
membrane
c. receptor protein – allows cell to communicate with outside environment
d. LDL cholesterol – helps keep membrane fluid and stable
VIRUSES (Latin for poison) text p.478
A. General Characteristics
1. A virus is an infectious agent made up of – nucleic acid (DNA or RNA), wrapped in protein coat
a. they have no nucleus, no organelles, no cytoplasm or cell membrane – non-cellular particle
b. viruses have either – DNA or RNA, but not both
2. Viruses are – parasitic - organism that depends entirely upon another living organism
(host) for its existence in such way that it harms that organism.
B. Examples:
1. Bacteriophage – viruses that infect a bacteria
3. Ebola
4. Common Cold
5. HIV
RNA
6. Herpes
7. H1N1
8. Avian Flu
2. Flu (influenza)
envelope –
(has marker proteins
+ carbs derived from
host cell)
capsid
Viruses: Based on the characteristics of life and the general characteristics of a virus, are viruses considered
dead or alive? Explain in the space below.
Dead:
 Structure – non cellular particles
 Reproduction – can only copy itself by using host cell
 Genetic Material – DNA OR RNA
 No growth or development
 Doesn’t obtain or use energy
 Doesn’t respond to its environment