Levels of Organization

Division of Labor & The First Level Within multi-cellular organisms there is division of labor. Division of labor means that the work (labor) of keeping the organism alive is divided (division) among the different parts of the body. Each part has a job to do and as each part does its special job, it works in harmony with all the other parts. The arrangement of specialized parts within a living thing is sometimes referred to as levels of organization. Cells of course, are the first level of organization.

Cells: LOTS of Different Kinds. Here are two examples Cells: LOTS of Different Kinds! Here are two examples. Can you guess what kind? Nerve Cells Skin Cells

Second Level: Tissues In any multi-cellular organism, cells rarely work alone. Cells that are similar in structure and function are usually joined together to form tissues. Tissues are the second level of organization. There are four basic/major types of tissues in the human body: Muscle tissue, nerve tissue, connective tissue, and epithelial tissue.

Let’s Look Again… Here are the cells we saw before, but if you look closely, you can see that they all look similar. Nerve cells working together make nerve tissue, and skin cells make up a special type of epithelial tissue.

Taken One At A Time…. Nerve tissue carries messages back and forth between the brain and every other part of the body. The brain, spinal cord, and nerves are made up of nerve tissue. Connective tissue connects and supports parts of the body. Blood, fat, ligaments, cartilage, bones, and tendons are all connective tissues. Muscle tissue can contract, or shorten. Because of this, muscle tissue makes parts of your body move. Epithelial tissue covers and lines the surfaces of your body and organs, inside and out. They primarily serve as protective barriers. Skin is one example.

Level Three: Organs When a bunch of different types of tissues work together, they form an organ. There are many organs in the body. GET IT????

Level Four: Organ Systems Each organ in your body is part of an organ system, a group of organs that work together to perform a major function. For example, your heart is part of your circulatory system, which carries oxygen and other materials throughout your body. Besides the heart, blood vessels are organs that work in your circulatory system.

The excretory system removes wastes. The nervous system detects and interprets information from the environment outside the body and from within the body; controls most body functions. The immune system fights disease. The excretory system removes wastes. The endocrine system controls many body processes by means of chemicals, like hormones.

The muscular system enables the body to move; moves food through the digestive system, and keeps the heart beating. The skeletal system supports and protects the body, and works with the muscular system to allow movement; makes and stores blood cells and stores some other materials.

The digestive system takes food into the body, breaks the food down into smaller particles, and absorbs the digested materials. The respiratory system takes oxygen into the body and eliminates carbon dioxide. The reproductive system produces sex cells that can unite with other sex cells to create offspring; controls male and female characteristics.

Let’s Review…. 1st Level: Cells working together form 2nd Level: Tissues, which can form 3rd Level: Organs, which work together to form 4th Level: Organ Systems, which work together to form 5th Level: Organisms!

Cell Structures, Functions and Transport

Discovery of Cells It wasn’t until the 1600s that scientists were able to use microscopes to observe living things.

Cells In 1665, Robert Hooke observed cork cells under the microscope. He called them cells. This is a drawing he made of the cork cells.

More Cork Cells Here is what cork cells look like in a modern microscope with special lighting.

diameter of DNA double helix tallest trees adult human chicken egg frog embryo most eukaryotic cells mitochondrion Figure: 04-01 Title: Relative sizes. Caption: Dimensions commonly encountered in biology range from about 100 meters (the height of the tallest redwoods) through a few micrometers (the diameter of most cells) to a few nanometers (the diameter of many large molecules). most bacteria virus proteins diameter of DNA double helix atoms

Cell Theory The Cell Theory States It wasn’t long before scientists realized that all living things were made up of cells. This discovery brought about the formulation of the cell theory. The Cell Theory States All living things are made of cells. Cells are the basic units of structure and function in living things. New cells are produced from existing cells.

Types of Cells Cells are classified as prokaryotic or eukaryotic. Prokaryotic cells have genetic material that is not inside a nucleus (no nucleus). Eukaryotic cells have genetic materials in a nucleus. (“true” nucleus)

Prokaryotes The prokaryotes are bacteria. They have cell walls, a plasma membrane, and a single chromosome in the nucleoid or nuclear region. Some may have flagella for movement.

Eukaryotes Eukaryotes are more complex organisms and have many specialized organelles. Eukaryotes include organisms from Protista, Fungi, Plantae, and Animalia.

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Nucleus Cell Membrane Go to Section:

Eukaryotic Cell Organelles and Function Nucleus Nickname: “The Control Center” Function: holds the DNA Parts: Nucleolus: dark spot in the middle of the nucleus that helps make ribosomes

The Nucleus Nucleus- The nucleus is the control center of the cell. It is the largest organelle in the cell and it contains the DNA of the cell. The DNA of all cells is made up of chromosomes.   DNA (Deoxyribonucleic Acid) contains all the information for cells to live, perform their functions and reproduce.  Inside the nucleus is another organelle called the nucleolus. The nucleolus is responsible for making ribosomes. The circles on the surface of the nucleus are the nuclear pores. These are where ribosomes, and other materials move in and out of the cell.

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Go to Section:

Eukaryotic Cell Organelles and Function Ribosomes Function: makes proteins Found in all cells, prokaryotic and eukaryotic

Ribosomes Ribosomes are protein assembly organelles. The ribosome connects the amino acids. Ribosomes can be “free” in the cytoplasm or on the endoplasmic reticulum. Ribosome can be found in both the Prokaryotes and Eukaryotes

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Go to Section:

Eukaryotic Cell Organelles and Function Endoplasmic Reticulum (ER) Nickname: “Roads” Function: The internal delivery system of the cell

Endoplasmic Reticulum 2 Types: Rough ER: Rough appearance because it has ribosomes Function: helps make proteins, that’s why it has ribosomes Smooth ER: NO ribosomes Function: makes fats or lipids

Endoplasmic Reticulum (ER) ER is a series of folded membranes within a cell smooth ER is site of most membrane synthesis rough ER looks spotted due to ribosomes bound on the surface rough ER is location of membrane, secreted or otherwise targeted protein synthesis eukaryotes only

Endoplasmic Reticulum (ER) ER is continuous with the nuclear membrane amount of ER varies by cellular function liver cells have lots of ER- used to detoxify (clean) chemicals cells optimized for protein secretion have lots of rough ER

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Ribosomes Section 7-2 Cytoplasm Ribosomes Nucleolus Nucleus Cell Membrane Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Golgi Complex Go to Section:

Eukaryotic Cell Organelles and Function Golgi Complex Nickname: The shippers Function: packages, modifies, and transports materials to different location inside/outside of the cell Appearance: stack of pancakes

Golgi complex- It is organelle in the cell that is responsible for sorting and correctly shipping the proteins produced in the ER.  Just like our postal packages which should have a correct shipping address, the proteins produced in the ER, should be correctly sent to their respective address.  In the cell, shipping and sorting done by the Golgi complex. It is a very important step in protein synthesis. If the Golgi complex makes a mistake in shipping the proteins to the right address, certain functions in the cell may stop.                                                                                              

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Golgi Bodies Go to Section:

Eukaryotic Cell Organelles and Function Lysosomes: circular, but bigger than ribosomes) Nickname: “Clean-up Crews” Function: to break down food into particles the rest of the cell can use and to destroy old cells

Lysosome Digestive 'plant' for proteins, fats, and carbohydrates Transports undigested material to cell membrane for removal Cell breaks down if lysosome explodes

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Mitochondria Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Golgi Bodies

Eukaryotic Cell Organelles and Function Mitochondria Nickname: “The Powerhouse” Function: Energy formation Breaks down food to make ATP ATP: is the major fuel for all cell activities that require energy

Mitochondria Produces energy through chemical reactions – breaking down fats & carbohydrates Controls level of water and other materials in cell Recycles and decomposes proteins, fats, and carbohydrates

Mitochondria Mitochondria are membrane-enclosed organelles distributed through the cytosol of most eukaryotic cells. Their main function is the conversion of the potential energy of food molecules into ATP Every type of cell has a different amount of mitochondria.. There are more mitochondria in cells that have to perform lots of work, for example- your leg muscle cells, heart muscle cells etc. Other cells need less energy to do their work and have less mitochondria.

Animal Cell Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Mitochondria Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Golgi Bodies

Now let’s talk about structures only found in PLANT Cells!!

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Cell Membrane Section 7-2 Vacuole Cell Membrane Go to Section:

Eukaryotic Cell Organelles and Function Vacuoles Function: stores water This is what makes lettuce crisp When there is no water, the plant wilts

Vacuoles Vacuoles are storage organelles. They store water, salts, proteins, etc. Plants have a large Central Vacuole that helps plants support leaves and stems.

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Chloroplasts Section 7-2 Vacuole Chloroplasts Cell Membrane Go to Section:

Eukaryotic Cell Organelles and Function Chloroplasts Function: traps energy from the sun to produce food for the plant cell Green in color because of chlorophyll, which is a green pigment

Chloroplasts Chloroplasts are organelles that capture sunlight energy and convert it into chemical energy in a process known as photosynthesis.

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Chloroplasts Section 7-2 Vacuole Chloroplasts Cell Membrane Cell Wall Go to Section:

Eukaryotic Cell Organelles and Function Cell Wall Function: provides support and protection to the cell membrane Found outside the cell membrane in plant cells

Plant Cell Cytoplasm Vacuole Smooth ER Ribosomes Chloroplasts Cell Membrane Cell Wall Nucleolus Golgi Bodies Nucleus Mitochondria Rough ER

Plant & Animal Cells Similarities Both constructed from eukaryotic cells Both contain similar organelles Both surrounded by cell membrane

Plant & Animal Cells Differences Animals have Plants have Cell wall – provides strength & rigidity Have chloroplasts, photosynthetic Animals have Other organelle not found in plants (lysosomes formed from Golgi) Centrioles, important in cell division

Comparing Plant and Animal Cells