Cells: The Building Blocks of Life

Cells Cell Theory Protocell Prokaryotes Eukaryotes Plant cell Animal cell Organells Cell membrane Osmosis Cytoplasm Nucleus Cell wall Ribosome Endoplasmic reticulum Golgi Apparatus Mitochondria Lysosome Vacuole Plastid Significant digits Cell cycle Synthesis Replication Mitosis Interphase Prophase Metaphase Anaphase Telophase Cytokinesis Meiosis Respiration Glucoes ATP Glycolysis Fermentation Aerobic Anaerobic Krebs Cycle Lactic acid

(24 min)         (22 min)

The Cell Theory: All living things are made of cells. Cells are the basic units of life. Cells come only from other cells.

Protocells:

One theory of the origins of cells states that the first life on earth consisted of several types of tiny protocells, cell-like organisms. These organisms were able to survive and reproduce in a very limited environment because of their simplicity. Over time, some of these protocells came together and shared their specialization in a symbiotic relationship. These colonies of protocells eventually became the cells we know today.

Types of cells:

Prokaryotes - cells with no nucleus or organells with membranes. Bacteria and blue-green bacteria are prokaryotic cells. Eukaryotes - cells that contain a nucleus and organelles surrounded by a membrane. The cells of protozoa, algae, fungi, plants, and animals are eukaryotic cells.

Pharmacy Technician

Except for bacteria, all organisms we will study this year will be eukaryotes. Plant cells and animal cells are similar, but do not have exactly the same cell parts and shape.

Lab #2
Cell organells: components of cells with specific functions.

(22 min)

Cell membrane   (bio lab 054)
• A complex barrier of lipid molecules separating the cell from its external environment.
• A group of molecules that can move apart to allow larger particles to move in or out of the cell.
   
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• The "selectively permeable" cell membrane regulates what passes into and out of the cell. Selectively permeable means some things get through but, others can't. This allows the cell to maintain a "balance" between what is inside the cell and outside.
• Some substances, like water, move freely through the cell membrane by a process known as osmosis.

  In osmosis, particles move easily from an area of high concentration to an area of low concentration by molecular motion only. Cells can push particles in the opposite direction, from low concentration to high, but it will take energy from the cell to do this.

Cytoplasm

• The cytoplasm is the liquid part of the cell. If you squeeze a blade of grass you will get a little of the plants cytoplasm on you.
• A thick, aqueous solution of salts surrounding the organelles inside the cell membrane.
• Nutrients and minerals spread through the cytoplasm to all parts of the cell.
• The constant motion of this gel-like substance is called cytoplasmic streaming.

Nucleus

• The structure inside the cell that directs cell activities.
• Contains the DNA of a cell.

During most of a cell's life cycle, the DNA is spread through the cytoplasm. The nuclear membrane forms, making the nucleus visible, only in preparation for cell division.

Cell wall

• On the outside of some cells, bacteria and plants, this structure functions for support and protection.
• There are pores in the cell wall allowing substances to come in contact with the cell membrane.
• Types of cell walls:
  • Primary cell wall - formed during cell growth, it is composed of parallel layers of celluloseand pectin. This structure allows the cell to expand as it grows. While it does provide support, it is not nearly as strong as the secondary cell wall.
  • Secondary cell wall - formed after cell growth stops, it is composed of interwoven cellulose and lignin fibers. This structure is very strong, but does not give. It gives plants their "woody" characteristic.
  • Cellulose from plants is the major substance composing paper.

Ribosome

• The sites of protein synthesis in a cell.
• These small, spherical structures are the most numerous organells in almost all cells.
• Some ribosomes produce protein to be used within the cell and some produce protein that is "exported" to other parts of an organism.

Endoplasmic reticulum

• A membrane system of folded sacs and tunnels in the cytoplasm.
• Rough "ER" is covered with ribosomes. It is common in cells that export proteins and directs the proteins flow.
• Smooth "ER" as few or no ribosomes. It functions as a pathway for molecules to follow.

Golgi Apparatus

• A stack of membranes or sacs that acts to prepare substances for export from the cell.
• Once the Golgi apparatus has enclosed the final product in a vesicle, or pouch, the product is sent through the cell membrane.

Mitochondria

• this is the energy producer in the cell.
• It's the respiration center of the cell.
• Large organells scattered through most cells, they are most numerous in cells that use a lot of energy like liver and muscle cells.

Lysosome

• Digestive centers of a cell.
• They produce many different types of enzymes and digest things from food particles to a cell's own worn out parts.

Vacuole Most common in plant cells, they are storage sites within a cell.

Test your knowledgeof the functions of cell organelles.

End Of Instruction practice test question #21

Homework Lab 032:
This assignment must be turned in by the end of the week to receive credit.
Model Self-evaluation Rubric

• Study this lab report guide.
• Use the model self-evaluation rubric to plan your model.

Computer Activity: Pick one of the cell drawings below. Plant Cell Animal Cell Center this picture at the top of a Word page. Center this picture below the first. From the "drawing" toolbar, use the "freeform" and "fill" tools to do the following: Color the square beside each cell part with the color used for that part in the drawing. Color each part in the cell drawing. Center this picture at the top of a Word page. Center this picture below the first. From the "drawing" toolbar, use the "freeform" and "fill" tools to do the following: Color the square beside each cell part with the color used for that part in the drawing. Color each part in the cell drawing.

Day 3

What group of cells in the human body does not have a nucleus?

Size of living things:

The smallest known living thing on Earth is a bacteria in the genus Coxiella. These bacteria are about 8 millionths of an inch (0.2 micrometers) in diameter. Their small size means these bacteria contain only 100 million to 120 million atoms. It is believed that fewer atoms would be unable to build the structures needed to store information and carry out the metabolic processes needed for life. While this may seem like a large number, keep in mind that the human body has over 5 Billion cells.

The largest known animal is the blue whale, Balaenoptera musculus. It is known to reach lengths over 100 feet (30+ meters) and weigh 120 tons.

The chart below indicates that all animal cells are about 10 micrometers in diameter. This means that the cells of a blue whale and a human are essentially the same size. The whale just has many more.

Galileo used scaling to prove that giants could not exist.

Measure and record the diameter of a large marble, a ping-pong ball, and a baseball, in centimeters, to 2 significant digits. Calculate the surface area and volume of each to 2 significant digits. Show how you set up the following calculations on your paper. Use 3.1 for in these calculations. The formula for calculating the surface area of a sphere issurface area = 4 r 2 The formula for calculating the volume of a sphere isV = 4/3 r 3

Draw a table like this on your paper and use your data and calculations to complete it. diameter of marble cm     surface area of marble cm2     volume of marble cm3         Surface Area / Volume =     diameter of ping-pong ball cm     surface area of ping-pong ball cm2     volume of ping-pong ball cm3         Surface Area / Volume =     diameter of baseball cm     surface area of baseball cm2     volume of baseball cm3         Surface Area / Volume =     How do surface area and volume compare as objects get larger?

Research Links:

• Cellular Biology - Altruis Biomedical Network
• Biology 100 - Wayne's World
• The Cell - Thinkquest
• Cell Structure - Carroll College
• Cell Biochemistry - Carroll College
• Virtual Cell - University of Illinois
• The Cell Nucleus - University of Texas Medical Branch at Galveston
• Cell Membranes - Texas A&M University
• Cells Alive - By James A. Sullivan
• Cell & Molecular Biology Online - Links by Pamela Gannon
• Cell Biology Hypertextbook - Massachusetts Institute of Technology
• Digital Learning Center for Microbial Ecology - Michigan State University

Animal cells never have a cell wall.

Red blood cells do not have a nucleus.
They are produced in the "flat" bones of the body, live for about 120 days, and die without reproducing. Their sole purpose is to carry oxygen and carbon dioxide in the blood.