Transcript Cells, Tissues, & Organs

Cell Theory
1. All organisms are composed of cells
2. Cells are the smallest unit of life
capable of self maintenance, and self
replication
3. All living cells are produced by
preexisting cells
Types of cells
1. Prokaryotic cells:
• No nucleus or internal membranous
organelles
• Small cells
• In the domains Bacteria and Archaea
Types of cells
2. Eukaryotic cells
• Nucleus and complex membranous
organelles
• Includes all animal cells, plant cells,
fungi cells, Protozoa
•All eukaryotic cells have
generally similar organelles.
•There are a few important
differences that are described
below.
Figure 3.14 A typical animal cell.
Copyright © 2009 Pearson Education, Inc.
Figure 3.14 A typical animal cell.
Copyright © 2009 Pearson Education, Inc.
Figure 3.1a A eukaryotic animal cell.
Copyright © 2009 Pearson Education, Inc.
Plasma (Cell) Membrane
• A boundary between the cell and
the environment
• Two layers of phospholipids
• Selectively permeable
Cell Membrane
Nucleus
• Nucleus – control center of the cell
• DNA (genetic material) is located inside
of the nucleus
• Nucleoli (inside nucleus) produce
ribosomes
Cytoplasm
• Cytosol-gel like substance
• Organelles-carry out specific
functions
Organelles - 1
• Ribosomes – Make proteins. May be attached
to RER or floating free in the cytosol
• Rough Endoplasmic Reticulum (RER) An array of tubules in the cytoplasm. Modifies
and transport proteins
Ribosomes and
Rough Endoplasmic Reticulum (RER)
Organelles - 2
• Smooth Endoplasmic Reticulum - involved in
the synthesis of lipids. Lacks ribosomes
• The Golgi Complex - Array of flattened sacs.
Packages proteins in vesicles for transport
outside or inside the cell
• Vesicles - transport proteins between
compartments
The Golgi Complex
Organelles - 3
• Mitochondria • Powerhouse of the cell
• Site of aerobic cellular respiration, which
releases energy from sugar
Mitochondria
Organelles - 4
• Lysosomes - Vesicles that contain digestive
enzymes. Break down old cell parts
• Cytoskeleton - The “skeleton” of the cell.
Consists of microtubules and microfilaments
• Vacuoles - Large membranous bubbles which
store substances inside the cell
Only in animal cells
Centrioles
• Paired structures composed of microtubules
• They form the mitotic spindle during cell
division
Only in plant cells
• Cell wall – rigid structure outside the cell
membrane, provides support to the cell
• Central vacuole - fluid filled cavity
• Chloroplasts – Contains the green pigment
chlorophyll. Convert sunlight into
carbohydrates
Plant cell
Aggregations of cells
• Tissue - a group of similar cells working
together to perform a specific function
• Organ - two or more tissues cooperating to
perform a certain life support function
• Organ System-a group of organs working
together to perform a general life support
function
• Organism