unit 2 h=chap. 4
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Cell Structure and Function. Unit 2 H=Chap. 4. What is a cell? Give me 2 examples. Types of Cells. Animal. Bacterial. Plant. Discovery of the Cell (4-1). In 1665, the English scientist ROBERT HOOKE, used a microscope to examine a thin slice of cork. - PowerPoint PPT PresentationTRANSCRIPT
Unit 2
H=Chap. 4
In 1665, the English scientist ROBERT HOOKE, used a microscope to examine a thin slice of cork.
He described it as consisting of “great many little boxes”.
It reminded him of the small rooms in which monks
lived… CELLS!
All living things are composed of one or more cells
Cells are the basic units of structure and function in all living things.
ALL cells come from preexisting cells.
1. SHAPE - Diversity of form reflects a diversity
of function
2. SIZE – visible with
unaided eye, microscopic,
etc.
MOST CELLS ARE SMALL FOR 2 REASONS
1. A SMALL CELL HAS MORE SURFACE AREA THAN A LARGE CELL FOR A GIVEN VOLUME OF
CYTOPLASM
2. THE CELL'S NUCLEUS (THE BRAIN) CAN ONLY CONTROL A CERTAIN AMOUNT OF LIVING, ACTIVE
CYTOPLASM
3. INTERNAL ORGANIZATION:
Organelles, Eukaryotes and
prokaryotes
EQ= What are membranes and what purpose do they serve?
Give an example of one.
1. THE PLASMA MEMBRANE (Present in ALL
cell types)
Functions:Regulates what enters/leaves the
cellSeparates internal environment
from the external environmentComposed of a lipid bilayer (Fat)Selectively-permeable membrane
The Fluid Mosaic Model
2. THE CELL WALL
(Plant cells ONLY)
•Surrounds the cell membrane
•Helps to protect and support the
cell
The fluid-filled area BETWEEN the NUCLEUS & the CELL MEMBRANE…fluid & organelles
“cyto” = cell “plasm” = fluid
Cytosol = cell fluid only
3. THE CYTOPLASM
4. THE NUCLEUS(Eukaryotic cells)
Control center of the cell Contains DNA Double Layer Membrane called the
NUCLEAR ENVELOPE covered with many small pores The NUCLEOLUS synthesizes (makes)
ribosomes, which are important in making proteins for the cell
Chromatin: nuclear DNA (long fibers known as
chromosomes)
Nuclear Envelope:
Double membran
e
Nuclear Pore:
Regulate flow of
materials in and out of
cell
Nucleolus:
Ribosome synthesis
Nucleoplasm:
Fluid of the nucleus
Extension of the nuclear membrane regions with ribosomes = ROUGH ER
(transport ribosomes) regions w/o ribosomes = SMOOTH ER
(lipid synthesis)
Sites of protein synthesis
2 sub-unit
The function of the Golgi Apparatus is
to sort, chemically alter, and package
important molecules. (UPS guy!)
Powerhouse of the cell… (generates fuel for cell’s activities)
Sites of cellular respiration
CHLOROPLAST
Responsible for intracellular digestion.
Lysosomes are membranous sacs of acidic enzymes. (Rare in plant cells)
Detoxify harmful substances that enter the body.
Stores extra material for the cell.
Nutrients, water, etc.
The “garage”
All CELLS HAVE DIFFERENT SHAPES AND ARE CAPABLE OF SOME TYPE OF MOVEMENT.
• HELPS SUPPORT CELL STRUCTURE AND DRIVE CELL
MOVEMENT.
a. Cilia – short hair-like extensions on the cell that aid in cell movement
b. Flagella – long hair-like extension on a cell that helps the cell propel