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Presentation on theme: "Cells!."— Presentation transcript:

1 Cells!

2 The Cell Theory All Living Things are composed of cells
Cells are the basic units of structure and function in living things New cells are produced form existing cells

3 Basic Cell Structures All cells have: Some cells have: Cell membrane
Cytoplasm: within the cell membrane, but not in the nucleus Some cells have: Cell wall Nucleus

4 Biologists divide cells into two categories: Eukaryotes and Prokaryotes

5 Prokaryotes Generally smaller and simpler
Have cell membranes and cytoplasm DO NOT CONTAIN NUCLEI All bacteria are prokaryotes Escherichia coli: lives in your intestines Staphylococcus aureus: can cause skin infections




9 Eukaryotes “Eu” – true “karyon” – nucleus Also have A cell membrane
Cytoplasm Organelles

10 Cell Walls Provides support and protection for the cell
Lies outside of the cell membrane Found in Plants Algae Fungi Nearly all prokaryotes *ANIMALS CELL DO NOT HAVE CELL WALLS






16 Use this article to define
Use this article to define Nucleosome Histone Chromatin Chromosomes Chromatosomes


18 Chromatin Granular material visible within the nucleus
Consists of DNA bound to protein Spread throughout the nucleus

19 Chromosomes When a cell divides, chromatin condenses to form chromosomes Chromosomes: Distinct, threadlike structures containing the genetic information that is passed from one generation of cells to the next

20 Nucleolus Most nuclei contain a small, dense region known as the nucleolus Assembly of ribosomes begins here

21 Nuclear Envelope Double membrane layer
Contains nuclear pores – allow material to move into and out of the nucleus Nucleus sends a steady stream of RNA and other information-carrying molecules to the rest of the cell through the nuclear pores

22 Central Dogma of Molecular Biology


24 Cytoskeleton

25 Cytoskeleton The cytoskeleton is a network of protein filaments that helps the cell to maintain its shape The cytoskeleton is also involved in many forms of cell movement The cytoskeleton is made up of a number of important structures: Microtubules Microfilaments (p 176)

26 Microtubules Hollow tubes of protein about 25 nanometers in diameter
Maintain cell shape and can serve as “tracks” along which organelles are moved Important in cell division – help separate chromosomes Form a pair of centrioles (animal cells) Can sometimes form cilia and flagella

27 Network of Microtubules connecting cellular organelles

28 Important in cell division – help separate chromosomes
Form a pair of centrioles (animal cells)

29 Microtubules can sometimes form cilia and flagella to help the cell move through liquid

30 Microfilaments Long, thin fibers that function in the movement and support of the cell 7 nm in diameter Tough flexible framework - support


32 Organelles in the Cytoplasm
Ribosomes Endoplasmic Reticulum Golgi Apparatus Lysosomes Vacuoles Chloroplasts Mitochondria Organelles = “tiny organs”

33 Ribosomes Making proteins Proteins are assembled ON ribosomes
Where are ribosomes assembled? Ribosomes: small particles made of RNA and protein Produce proteins by following coded instructions that come from the nucleus This coded instruction is called mRNA


35 Endoplasmic Reticulum
An internal system of membranes Only in eukaryotes The endoplasmic reticulum is the organelle in which components of the cell membrane are assembled and some proteins are modified Rough ER Smooth ER

36 Rough Endoplasmic Reticulum
Involved in the synthesis of proteins “Rough” due to the ribosomes on the surface Newly made proteins move directly from these ribosomes into the rough er, where they are chemically modified


38 Smooth ER No ribosomes on surface It is an extension of the Rough ER
Contains many enzymes that performed specialized tasks Ex: Synthesis of lipids


40 Rough & Smooth ER

41 Golgi Apparatus Proteins produced by the rough endoplasmic reticulum move into a stack of membranes called the Golgi Apparatus Enzymes in the Golgi apparatus attach carbohydrates and lipids to proteins From the Golgi apparatus, proteins are sent to their final destination


43 Golgi Apparatus Cis face: receiving side Trans face: shipping side


45 Lysosomes Small organelles filled with enzymes
Breaks down lipids, carbohydrates, and proteins from food into particles that can be used by the rest of the cell Also break down “old” organelles Remove debris

46 Digestion Organelle degradation

47 Vacuoles Store water, salts, proteins, and carbohydrates
Saclike structures Found in single-celled organisms and animals Vesicles: smaller vacuoles involved in transporting substances Useful in plants Pressure in these central vacuoles makes it possible for plants to support heavy structures such as leaves and flowers


49 Chloroplasts Found in plants and some other organisms
Not found in animal and fungal cells Chloroplasts use the energy from sunlight to make energy-rich food molecules in a process known as photosynthesis Bound by two envelope membranes and contain large stacks of photosynthetic membranes Green pigment chlorophyll is located in the photosynthetic membranes - thylakoid


51 Mitochondria Mitochondria use energy from food to make high-energy compounds that the cell can use to power growth, development, and movement Found in almost all eukaryotic cells Including plant and algae cells Enclosed by an outer and an inner membrane Inner membrane is folded


53 Organelles that contain their own DNA
Chloroplasts Mitochondria This DNA contains information that is essential for the normal function of these specific organelles

54 Mitochondrial DNA All of a mitochondria come from the cytoplasm of the ovum, or egg cell So, genes in the mitochondria are specifically genes from your mother

55 Endosymbiotic Theory

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