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Cell Organelles and Features

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Presentation on theme: "Cell Organelles and Features"— Presentation transcript:

1 Cell Organelles and Features

2 The Plasma membrane Also called the cell membrane
Selectively permeable The cell structure that encloses the cell and regulates the passage of materials between the cell and its environment Allows nutrients into the cell Allows waste to leave the cell Also aids in protection and support of the cell.

3 STRUCTURE OF CELL MEMBRANE
Made primarily of phospholipids Have polar, hydrophilic “water-loving” head Have a nonpolar, hydrophobic “water-fearing” tail Water molecule surround the cell membrane The phospholipids form into a phospholipid bilayer Cholesterol is found in the membrane to make it more rigid and prevent it from freezing at low temperatures

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5 Membrane proteins Cell membranes contain specific proteins
Integral proteins are embedded within the bilayer Peripheral proteins are on the only one side of the bilayer and are not embedded into it

6 Fluid Mosaic Model The phospholipid bilayer behaves like a fluid, more than a solid. The phospholipid bilayer allows other molecules to “float” in the membrane.

7 Cytoplasm Gel-like material that fills the cell.
In prokaryotic cells all the processes that keep the cell alive happen right in the cytoplasm. Eukaryotic cells have organelles in which those processes happen. Cytoplasm video clip.

8 Cytoskeleton It is a supporting network of long, thin protein fibers that also provide an anchor for organelles. Microtubules - long hollow protein cylinders Microfilaments – thin protein threads Still images

9 The Nucleus Most of the functions of a eukaryotic cell are controlled by the nucleus Contains the chromosomes which are composed of DNA (deoxyribonucleic acid) Surrounded by a double membrane called the nuclear envelope Nuclear envelop contains proteins lined nuclear pores that are passage ways for RNA and other materials to enter/exit the cell

10 Nucleolus A denser area of the nucleus Site where DNA is concentrated

11 Mitochondria The “power house” of the cell Has its own DNA
Sites of cellular respiration, a process which supplies the cell with ATP (Adenosine triphosphate) Bound by a double membrane The inner membrane had many folds called cristae that carry out cellular respiration

12 Ribosomes Small, roughly spherical organelles that are responsible for making proteins. Ribosomes do not have a membrane Some are found freely floating in the cytosol Others are attached to the rough endoplasmic reticulum

13 Endoplasmic Reticulum (ER)
A complex, extensive network that transports materials throughout the inside of a cell. Two Types: Rough ER has ribosomes attached to the surface is ribosome-studded. Produces proteins and phospholipids Smooth ER has no attached ribosomes. Builds lipids like cholesterol

14 Golgi apparatus Contains sacs that receive materials from the ER.
Modifies, collects, packages, and distributes molecules within the cell or outside the cell.

15 VESICLES Small, round sacs that are surrounded by a single membrane

16 Lysosomes Contain chemicals called enzymes necessary for digesting certain materials in the cell Break down old worn out cell parts Can break down macromolecules Responsible for breaking down cells when it is time for the cell to die Play an important role in maintaining the overall health of an organisms by destroying cells that are no longer functioning correctly

17 Centrioles A small group of microtubules that help in cell division occurs. Video clip

18 Vacuole “Storage” spaces A sac to store food, water ,carbohydrates, enzymes, salts and other materials needed by the cell. Vacuoles in animal cells (if they are present) are much smaller than those in plant cells. Video clip

19 Organelles found in plant cells

20 Cell Wall Found in plants, fungi and some bacteria
Cell structure that surrounds the cell membrane for protection and support Allows for specific substances to pass in and out of the cell. Made of cellulose Video clip

21 Why do plants need cell walls?
Cell walls provide structural support for plants like a Skelton provides structural support for your. Without cell walls, plants would not be able to stand up What is important about cellulose? It is a macromolecule that humans cannot digest because they do not have the necessary enzymes; therefore, it passes through your digestive system as “fiber,” cleaning out the intestines.

22 Chloroplast Contain the green pigment, chlorophyll, which absorbs energy from the Sun to convert carbon dioxide and water into sugar through the process of photosynthesis. Video clip

23 movement structures Cilia
Short, numerous projections that look like hairs Flagella Longer and less numerous than cilia 400x Create movement with a whiplike motion 26,367x

24 The Characteristics of Fungi
Fungi are NOT plants Nonphotosynthetic Eukaryotes Nonmotile Most are saprobes (live on dead organisms)

25 The Characteristics of Fungi
Absorptive heterotrophs (digest food first & then absorb it into their bodies) Release digestive enzymes to break down organic material or their host Store food energy as glycogen BREAD MOLD

26 The Characteristics of Fungi
Important decomposers & recyclers of nutrients in the environment Most are multicellular, except unicellular yeast Lack true roots, stems or leaves MULTICELLULAR MUSHROOM UNICELLULAR YEAST

27 The Characteristics of Fungi
Cell walls are made of chitin (complex polysaccharide) Body is called the Thallus They may have several nuclei within a single cell. Grow as microscopic tubes or filaments called hyphae

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29 The Characteristics of Fungi
Some are edible, while others are poisonous EDIBLE POISONOUS

30 The Characteristics of Fungi
Produce both sexual and asexual spores Classified by their sexual reproductive structures Spores come in various shapes

31 The Characteristics of Fungi
Grow best in warm, moist environments Mycology is the study of fungi Mycologists study fungi A fungicide is a chemical used to kill fungi Fungicide kills leaf fungus

32 The Characteristics of Fungi
Fungi include puffballs, yeasts, mushrooms, toadstools, rusts, smuts, ringworm, and molds The antibiotic penicillin is made by the Penicillium mold Penicillium mold Puffball

33 Differences between Plant Cells and Animal Cells
Vacuole small or absent Large central vacuole Glycogen as food storage Starch as food storage Nucleus at the center Nucleus near cell wall

34 Similarities between plant cells and animal cells
Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

35 Differences between plant cells and animal cells
Relatively smaller in size Relatively larger in size Irregular shape Regular shape No cell wall Cell wall present


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