Lesson 7 Cell Structures Use this presentation in conjunction with the Cell Organelle note-taking worksheet. Run through the entire presentation before using it in class so that you know what’s coming next! It helps to print the outline and notes to have with you while presenting so that there are no surprises. –JessB.org

Differences in Cells Usually the shape of a cell is related to its function (job) Plant cells have a boxlike shape and animal cells do not have a particular shape Plant cells have some structures that animal cells do not – cell wall and chloroplasts A plant cell usually has one large vacuole and an animal cell usually has several small ones You may or may not wish to distinguish between cytosol and cytoplasm. The correct use of each term is shown here. Most high school textbooks, however, use the word “cytoplasm” to mean “cytosol.”

Cell Organelles the parts inside a cell they carry out functions (jobs) inside the cell You may or may not wish to distinguish between cytosol and cytoplasm. The correct use of each term is shown here. Most high school textbooks, however, use the word “cytoplasm” to mean “cytosol.”

Cell Membrane A thin, flexible barrier that surrounds a cell Controls what goes into or out of the cell Protects and supports the cell Emphasize word parts here: phospho= phosphate head; lipid= fatty acid tail bi= 2

Nucleus “Control center of the cell” - Directs all cell activities Usually the easiest organelle to see under a microscope Cells with a nucleus (plant cells and animal cells) are called eukaryotes and those without a nucleus (bacteria) are called prokaryotes Cells with more than one nucleus include muscle cells and liver cells, largely because of the massive volume of cytoplasm and number of organelles that need controlling.

Nuclear Membrane Surrounds the nucleus Controls what goes into and out of the nucleus Cells with more than one nucleus include muscle cells and liver cells, largely because of the massive volume of cytoplasm and number of organelles that need controlling.

Inside the Nucleus Chromosomes – structures in the nucleus made of DNA DNA – long, threadlike, material that contains the instructions for everything the cell does Cells with more than one nucleus include muscle cells and liver cells, largely because of the massive volume of cytoplasm and number of organelles that need controlling.

Cytoplasm Gel-like substance inside the cell Fills the space between all the cell parts and gives the cell its shape Actin, also found in muscle cells, mainly help maintain cell shape in their cytoskeletal role. Microtubules mostly move organelles around the cell. Intermediate filaments also provide structural support.

Endoplasmic Reticulum A.k.a. “ER” Moves materials around the cell It’s not necessary that the students can read the labels here; just point out the black dots are ribosomes.

Ribosome Smallest and most abundant organelles Makes proteins Proteins are very important for many of the cell’s activities A polypeptide is a chain of amino acids. In this diagram, you can see the ribosome is making a polypeptide, also known as a protein.

Golgi Apparatus Sends proteins to where they are needed AKA Golgi Complex. It is not necessary that the students read the labels, this diagram gives them a general idea of the Golgi’s shape.

Lysosomes Break down food, cell wastes, and old, worn-out organelles These materials are recycled and used again Students should recognize the shapes of the Golgi and ER even if they cannot read the captions.

Mitochondria “Powerhouse of the cell” Cellular respiration occurs here to release energy for the cell to use to make materials and move them around Explain that this diagram shows the mitochondria cut open to reveal the internal membranes.

Vacuoles Storage container for water, food, and wastes Vacuoles are larger in plant cells than they are in animal cells The image is 2D, so it must have been a light microscope or TEM. If the cell is very tiny, then a TEM was used. Otherwise, a strong light microscope could have captured this image.

Cell Wall Found only in plant and bacterial cells Rigid, protective barrier that protects and supports the cell Found outside of the cell membrane of plant and bacterial cells This is an actual microscopic image. Explain that the colors are added digitally to enhance the different parts.

Chloroplast Found only in plant cells Contains the green pigment chlorophyll Where photosynthesis takes place Chloroplasts absorb light, which is the catalyst for photosynthesis.

Review Which organelle directs all cell activities? Nucleus Which organelle controls what goes into or out of the cell? Cell membrane Which organelle controls what goes into and out of the nucleus? Nuclear membrane What substance contains the instructions for everything the cell does? DNA You may choose to delete the answers from the PowerPoint or change the animation so that they come in after all 5 questions are asked in case you want to quiz students individually at the end.