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Chapter 7 Notes Cells
CELL FUNCTIONS:
1. Digestion
2. Absorption (ingestion)
3. Biosynthesis- to make
4. Respiration- using oxygen to change food into a usable form of energy
5. Reproduction- cell division (fission)
6. Excretion- getting rid of waste
7. Secretion- passing out of materials produced by cells that are needed by other
cells
8. Response
9. Transportation- movement of materials (ex. Food) inside a cell
10. Growth
TWO TYPES OF CELLS:
1. Prokaryotes- “Pro” means before
“Karyote” means nucleus
1. has nuclear material
2. no nuclear membrane to separate nuclear material from the rest of the cell
3. few organelles, do not have ribosome’s
4. bacteria and blue-green algae
2. Eukaryotes- “Eu” means true
1. nuclear material enclosed in a nuclear membrane
2. many organelles
3. animal and plant cells (except blue-green algae)
Producer- organism that can make its own food (ex. Green plants)
Consumer- organism that cannot make its own food (ex. Animals)
HISTORY AND DEVELOPMENT OF THE CELL THEORY
1665- Robert Hooke (English) named cells he found in cork (dead cells)
1676- Anton van Leeuwenhoek (Dutch) observed and made drawings of small
organisms found in tooth scrapings (called them animalcules) (living cells)
1824- R.J.H. Dutrochet (French) stated that all plant and animal tissues were made up
of groups of cells. Explained that tissue growth was due to growth of individual cells.
1835- Felix Dujardin (French)- stated that single celled organisms were complete self
sufficient living things.
1838- Mathias Schleiden (German)- all plants were made of cells
1839- Theodor Schwann (German)- all animals were made of cells
Schleiden and Shwann- proposed that cells were the basic units of structure and
function in all living things.
1855- Rudolf Virchow (German)- all living cells come only from other living cells
1970- Lynn Margulis- proposed the idea that certain organelles, were once free-living
cells themselves
CELL THEORY- 1) cells are the basic unit of structure and function of living things, 2)
living cells are produced from other living cells 3) all living things are made up of cells
LEVELS OF ORGANIZATION
Cells are often organized to better serve the needs of the organism. The levels of
organization in living things often begin at the microscopic level with organelles.
Organelles working together form cells. Cells rarely work alone. Similar cells working
together for a specific function are called tissues. Organs are groups of different tissues
that work together. Organs work together and form specific systems. An organism is an
entire living thing that carries out all of the basic life functions and is made of organ
systems. The levels of organization from smallest to largest are:
Organelles----> Cells------> Tissues-----> Organs-----> Systems-----> Organisms
CELL ORGANELLES
1.Cell Wall
A. Found in plants cell (fungi, bacteria and some protest_ not in animal cells.
A. Nonliving outermost structure.
B. Provides protection and support for plants cells.
C. Made of cellulose (carbohydrate)
D. Hard, but allows H2O, O2, and CO2 and other dissolved materials to pass
through.
2. Cell Membrane. (Plasma membrane)
A. Outermost structure in animal cells
B. Plant cells also have – located just inside the cell wall.
C. Living material.
D. Function – regulates movement of materials into and out of cell.
1) Permeable – allows substances to pass through.
2) Impermeable – prevents substances from passing through.
3) Selectively permeable – (Semi-permeable) allows some substances
through while stopping other substances from passing through the cell
membrane
E. The cell membrane allows a cell to maintain a stable internal environment as
change occur in environment outside the cell (Homeostasis)
3. Nucleus
A. Large oval or spherical structure.
B. Made of proteins, enzymes, contain hereditary material.
C. Function – control center of cell/direct all activities of cell.
D. Parts of nucleus
1) Nuclear membrane – regulates what enters and leaves membrane
2) Nucleoplasm – everything inside the nuclear membrane.
3) Nucleolus – ribosorne RNA is made and stored here
4. Cytoplasm
A. Clear thick protoplasm that fills the space between cell membrane and nucleus
B. Always moving
C. Organelles suspended in
5. Ribosomes
A. Site where proteins are made
B. Some float freely in cytoplasm and some are attached to E.R.
6. Endoplasmic Reticulum- E.R.
A. Canal-like membrane system in cytoplasm
B. Function- 1) Rough E.R. (contains ribosomes) – protein synthesis and
transportation of proteins 2) Smooth E.R. (no ribosomes)
7. Mitochondria
A. Oval, rod-shaped
B. Function- “Powerhouse of cell” respiration
C. Supply energy for cell- break down food substances to release energy
8. Vacuoles
A. Found in plant and animal cells
B. Plant cells- larger and more numerous
C. Function- stores food, enzymes, water, other materials needed by cell
9. Lysosome
A. Small, round
B. Contain enzymes
C. Rare in plants- usually in cytoplasm of animal cells
D. Function- 1) Digestion 2) Destroy bacteria 3) Get rid of dead cells
10. Golgi Apparatus
A. Closely stacked flattened sacs
B. package substances that cells make
11. Plastids
A. Found in plant cells and some unicellular organisms
B. Function- 1) Make food 2) Store food 3) Give color
C. Leucoplast- Stores oils, starches, and protein
D. Chromoplast- different pigment give color
Chloroplast- a type of Chromoplast (makes plants green, traps sunlight for
photosynthesis)
12. Microtubules- (part of the cytoskeleton) thin hollow cylinders made of protein; help
animal cells to maintain shape- spindle fibers move chromosomes
13. Microfilaments- (part of the cytoskeleton) involved in changes in shape of cells
14. Centrioles- Found in animal cells; necessary for reproduction of cells- necessary for
spindle fiber formation