Post on 24-Feb-2016
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Cell Structure
Chapter 5
Typical Animal Cell
Cell Membrane
• What separates the cell from the outside environment
• “Fluid Mosaic” model • Functions – Transportation of materials in and out of cell– Cell recognition – Cell communication – Homeostasis
Please Label this Diagram
Fluid Mosaic Model • Cell membrane has both solid and liquid properties • Membrane made of lipid and protein • Phospholipid bilayer – fluid part
– Hydrophobic tail – Hydrophilic head
• Proteins, carbohydrates, cholesterol, etc embedded in bilayer – mosaic part
• Membrane is selectively permeable
Please Label this Diagram
Cell Wall
• Surrounds cell membrane in plant, algae, and some bacterial cells
• More protection and support • Is very porous – Allows water, oxygen, carbon dioxide, and other
substances to pass through • Made of cellulose
Nucleus • Information center of the cell– Controls metabolism, growth, differentiation,
structure and reproduction of the cell • Contains DNA (in chromosomes)• Controls actions of the
cell including cell reproduction
Parts of The Nucleus • Nuclear Envelope – 2 membranes that surround the nucleus
• Nuclear Pores – Openings in the nuclear envelope that allow molecules to move
in and out of the nucleus • Nucleolus – Small region made up of RNA and proteins – Where ribosomes are made
• Chromosomes – DNA in the nucleus – Contains genetic information
Organelles
• Small bodies with specific structures and functions within the cell
Cytoplasm
• Liquid substance between the nucleus and the cell membrane
• Contains organelles of the cell
“Mighty” Mitochondria – energy makers • Largest organelle (after nucleus) • Double membrane • Change energy stored in food into compounds that can be used by
the cell • Cristae – folds of inner membrane to increase SA for cellular
respiration • Matrix - inner part, similar to cytoplasm of cell • Contain some of their own DNA and ribosomes • Can self replicate • Other functions
– Control water/ion concentration • Cellular Respiration
– C6H1206 + 6 O2 ATP + 6 C02 + 6 H20
Chloroplasts – food makers for the world
• In plant cells only • Trap energy from sunlight and convert it into
energy that can be used by the cell• Photosynthesis (reverse cell respiration)– 6 C02 + 6 H20 + ATP C6H1206 + 6 O2
Ribosomes
• Structures where proteins are made• Made of rRNA and protein• One of the smallest organelles
• Polysomes: free floating groups of ribosomes
Endoplasmic Reticulum (ER)
• Complex network of sacs• Begins just outside the nucleus • Function: transports materials through the inside of
the cell • 2 types – Smooth ER: no ribosomes on the walls
• Lipid (hormone and steroid) synthesis• Detoxifies drugs and chemicals in the cell
– Rough ER: ribosomes on walls• Protein synthesis
Golgi Body (Apparatus)
• Proteins are sent to Golgi (from RER) for more modifications
• Proteins then used in other parts of cell or transported out of cell
• Golgi functions – Modifier – Collector – Packager – Distributer
Lysosomes – “clean up crew” • Contain chemicals and enzymes • Formed by Golgi • Not found in plants • Functions
– Cellular digestion – Auto-digestion/disposal of cell components– Breakdown of whole cells – Destroy bacteria
• Endocyctosis – cells that “engulf” other material – Process that allows larger items
to enter the cell
Vacuoles – “storage tanks”
• Saclike structures formed from other membranes within the cell
• Store/transport water, salts, proteins, carbs • Plants usually have a single large vacuole • Vesicles are small vacuoles
Cytoskeleton
• Made of filaments and fibers – Microtubules – support for
cell shape, form centrioles (used in cell division)
– Cilia/flagella – made of multiple microtubules • Used for cell movement
– Microfilaments – long fibers for movement and support
Centrioles
• Near the nucleus • 2 cylinder shapes • Are part of cell division
Prokaryotic vs Eukaryotic
Prokaryotes• Single celled organisms • Lack nucleus• Lack membrane bound
organelles
Eukaryotes • Multi- celled organisms • Have a nucleus • Have membrane bound
organelles