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Ch 4 – A Tour of the Cell  The cell is the basic unit of structure and function in the body.  Prokaryote v. Eukaryote Are smaller than eukaryotic cells.

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Presentation on theme: "Ch 4 – A Tour of the Cell  The cell is the basic unit of structure and function in the body.  Prokaryote v. Eukaryote Are smaller than eukaryotic cells."— Presentation transcript:

1 Ch 4 – A Tour of the Cell  The cell is the basic unit of structure and function in the body.  Prokaryote v. Eukaryote Are smaller than eukaryotic cells Lack internal structures surrounded by membranes Lack a nucleus  There are three principal parts: –plasma membrane (plasmalemma) –cytoplasm and organelles –nucleus..

2 Prokaryotic flagella Nucleoid region (DNA) Ribosomes Plasma membrane Cell wall Capsule Pili

3 Cytoskeleton Ribosomes Centriole Lysosome Flagellum Not in most plant cells Nucleus Smooth endoplasmic reticulum (ER) Golgi apparatus Rough endoplasmic reticulum (ER) Mitochondrion Plasma membrane

4 Cytoskeleton Mitochondrion Nucleus Rough endoplamsic reticulum (ER) Ribosomes Smooth endoplasmic reticulum (ER) Golgi apparatus Plasmodesmata Plasma membrane Chloroplast Cell wall Central vacuole Not in animal cells

5 The plasma membrane is composed of a phospholipid bilayer with embedded proteins. Hydrophilic region of protein Phospholipid bilayer Hydrophobic region of protein (b) Fluid mosaic model of membrane

6 The functions of plasma membrane include: –selectively permeable and surrounds the cellular contents. –regulates the passage of materials into and out of the cell. –participates in intercellular communications..

7 Transport of materials across the plasma membrane In general: –large macromolecules cannot cross the membrane –charged molecules cannot cross the membrane –small, non-charged molecules can cross –water can cross..

8 The cytoplasm (cytosol) is the gelatinous material inside the cell membrane but outside the nucleus. The cytoplasm contains organelles which are sub-cellular structures that perform discrete functions. True organelles are bounded by a phospholipid membrane..

9 The nucleus is a double-membrane organelle containing the nucleic acids (DNA) and at least one nucleolus (contains ribosomal RNA). This organelle stores the genetic infor- mation and contains the blueprints for almost all protein syntheses. –DNA RNA protein..

10 RibosomesChromatic Nuclear envelope NucleolusPore

11 Organelles of a Typical Cell Storage..Vacuole & vesicle Packages material for export & processes macromolecules Golgi Apparatus Passageway for materials Produces proteins & processes molecules for secretion Produces lipids & detoxifies drugs & stores Ca ++ Endoplasmic Reticulum (ER) *Rough *Smooth Production of proteins – located attached to ER or free-floating Ribosome

12 Aerobic cellular respiration: C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O +ATP Mitochondria Carries out photosynthesis: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Chloroplasts Contains digestive enzymes. Each contains one specific enzyme. Lysosome Surface projections – increase surface area & produce movement.. Cilia, flagella, microvilli

13 Plant cells are encased by cell walls –These provide support for the plant cells Walls of two adjacent plant cells Vacuole Plasmodesmata (channels between cells) CELL-CELL INTERACTIONS

14 Animal cells lack cell walls –They secrete a sticky covering called the extracellular matrix –This layer helps hold cells together Animal cells connect by various types of junctions –Tight junctions –Adhering junctions –Communicating junctions

15 Extracellular matrix (a) Tight junctions (b) Anchoring junctions (c) Communicating junctions Plasma membranes of adjacent cells Extracellular matrix


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