1. The fundamental life processes of plants and animals depend on a variety of chemical reactions that
occur in specialized areas of the organism’s cells. As a basis for understanding this concept:
1. c. Students know how prokaryotic cells, eukaryotic cells (including those from plants and animals), and
viruses differ in complexity and general structure.
All living cells are divided into one of two groups according to their cellular structure. Prokaryotes have no
membrane-bound organelles and are represented by the Kingdom Monera, which in modern nomenclature is
subdivided into the Eubacteria and Archaea. Eukaryotes have a complex internal structure that allows thousands
of chemical reactions to proceed simultaneously in various organelles. Viruses are not cells; they consist of only
a protein coat surrounding a strand of genetic material, either RNA or DNA.
1. e. Students know the role of the endoplasmic reticulum and Golgi apparatus in the secretion of proteins.
There are two types, rough and smooth, of endoplasmic reticulum (ER), both of which are systems of folded
sacs and interconnected channels. Rough ER synthesizes proteins, and smooth ER modifies or detoxifies lipids.
Rough ER produces new proteins, including membrane proteins. The proteins to be exported from the cell are
moved to the Golgi apparatus for modification, packaged in vesicles, and transported to the plasma membrane
for secretion.
1. j.* Students know how eukaryotic cells are given shape and internal organization by a cytoskeleton or cell
wall or both.
The cytoskeleton, which gives shape to and organizes eukaryotic cells, is composed of fine protein threads
called microfilaments and thin protein tubes called microtubules. Cilia and flagella are composed of
microtubules arranged in the 9 + 2 arrangement, in which nine pairs of microtubules surround two single
microtubules. The rapid assembly and disassembly of microtubules and microfilaments and their capacity to
slide past one another enable cells to move, as observed in white blood cells and amoebae, and also account for
movement of organelles within the cell.
Notes:
The cell is the basic structural unit of life, and the smallest unit of living things that are considered “alive”. Each
cell performs necessary functions such as respiration, consumption of nutrients, and removal of waste in order
to stay alive. Cells have developed specialized structures called organelles to aid them in these functions. Cells
are divided into two types: prokaryotes, representative of bacteria and other organisms which lack specialized
organelles, and eukaryotes – plants, animals and fungi which contain organelles.
Viruses are, by far, the smallest organisms in the world. Viruses are stripped down to an absolutely minimal
design: a protein capsule containing genetic information in the form of DNA or RNA. Viruses survive and
reproduce by infecting a cell and commandeering the cellular synthetic machinery to make more viruses. Then
the viruses break the cell open and start the cycle over again.
AIDS Virus
Bacterial Virus (phage)
Eukaryotic Plant and Animal Cell Diagrams
Organelles found in both plant and animal cells
Nucleus—a spherical membrane bound structure that is the control center for cell metabolism and reproduction. Holds the chromosomes
(DNA) of the cell.
The membrane that surrounds the nucleus is called the nuclear membrane it is a double membrane with many pores in it. Within the
nucleus are several nucleoli- or dark spots that are the sites for the production of ribosomes (another organelle).
Ribosomes—are small round bodies that are the site of protein synthesis. They are attached to another organelle called the endoplasmic
reticulum, or are freely floating in the cytoplasm.
Endoplasmic reticulum—a series of interconnecting membranes. Serve to transport cellular materials around the cell. They also store,
and synthesize substances. There are two types of endoplasmic reticulum: smooth and rough.
Cytoplasm—a watery material that aids in the cell's metabolism.
Golgi bodies—stacks of flattened sacks that serve a processing, packaging, and storage centers for products released form the cell.
Secretion.
Lysosome—a saclike structure that contain the digestive enzymes to help digest the cell's nutrients.
Vacuoles—membrane enclosed sacks used to store materials like water and or digested food.
Mitochondria—site of cellular respiration. Called the powerhouse of the cell. Contain their own DNA and are able to reproduce on their
own. A possible exception to the cell theory: endosymbiosis.
Microtubules—long hollow cylinders made of a protein called tubulin. Act as the cell's cytoskeleton (cell skeleton).
Microfilaments—long, thin solid filaments made of a protein called actin. Associated with the cell's ability to move and change shape.
Cilia and Flagella—are hair-like organelles that allow cells to move. Cilia are like eyelashes, flagella are like fish tails.
Cell membrane— Separates the cell from its environment. Regulates the transport of certain materials into and out of the cell (it is
Selectively Permeable). Made of fat (lipid), phosphorus and protein molecules.
Cell organelles found only in plant cells
Chloroplasts—Structures found only in green plant cells and some algae. Contain chlorophyll so that a plant may acquire nutrition by
photosynthesis.
Cell wall—Another organelle found only in plant cells. A non-living structure made mostly of cellulose, which surround the plant cell and
provides support. Its like the crunchy stuff in lettuce, celery, and carrots.
Organelle found only in animal cells
Centrioles—a pair of cylindrical organelles involved when the cell undergoes reproduction.