G7 ch2.2 the cell
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Transcript of G7 ch2.2 the cell
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The CellCHAPTER 2 LESSON 2P.51-58
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Vocabulary
•Cell membrane•Cell wall•Cytoplasm•Cytoskeleton•Organelle•nucleus
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Outline
• Review Cells and cell Theory
• Cell Shape• Cell Types
– Pro/Eu– Types of Eu cells
• Cell Parts– Cell Membrane– Cell Wall– Cell Appendages– Cytoplasm and
Cytoskeleton
• Cell Organelles– Nucleus
• Chromosomes• Nuclear envelope
– Ribosomes– Rough ER– Smooth ER– Mitochondria
• ATP– Chloroplasts
• Glucose– Golgi Apparatus
• Vesicles– Vacuoles
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Cells
• Smallest living unit• Most are microscopic
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Cell Size
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Cell Diversity- ShapeCell Diversity- Shape
• Cells differ widely in shape.
• Size and shape relate to their function.
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Principles of Cell Theory
• All living things are made of cells
• Smallest living unit of structure and function of all organisms is the cell
• All cells arise from preexisting cells
(this principle discarded the idea of
spontaneous generation)
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Characteristics of All Cells
• A surrounding membrane
• cytoplasm – cell contents in thick fluid
• Organelles – structures for cell function
• Control center with DNA
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Cell Types
• Prokaryotic
• Eukaryotic
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Prokaryotic Cells
• First cell type on earth• Cell type of Bacteria and Archaea• Most are unicellular organisms
called prokaryotes
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Prokaryotic Cells
• No nucleus
• DNA floats freely in the cytoplasm
• No organelles, only free floating proteins
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Eukaryotic Cells• Nucleus – DNA surrounded by a nucleus• Include fungi, protists, plant, and animal cells• Possess many organelles• Much larger than prokaryotic cells
Protozoan
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Prokaryote vs. Eukaryote
• Pro = No nucleus
• Eu = Yes, there is a nucleus
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Representative Animal Cell
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Representative Plant Cell
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Organelles
• In eukaryotic cells
• Cellular machinery
• Different functions
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Cell Membrane
• All cells• Protects the inside of a cell from the outside• Made of proteins and lipids called
phospholids
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Phospholipids
Protein
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Movement Across the Plasma Membrane
• Some things move freely in and out of the cell• Some things are blocked and need proteins to
help them cross the membrane
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Cell Walls
• Found in plants, fungi, & many protists• Surrounds plasma membrane• Gives shape and support
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Cell Wall Differences• Stiff structure• Protects from viruses and other
harmful organisms• Has holes that connect cell
membranes between cells
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Cytoplasm
• Fluid inside the cell• Mostly water and salts• Cytoskeleton
– Proteins that are the framework of a cell– Like a skeleton or web of stick-like proteins– Gives shape– Helps the cell move
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Cell Appendages
• Help with movement– Flagella – tail-like and whips back and forth– Cilia – fine-hairs that move the cell or
molecules around it
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Nucleus
• Control center of cell• Usually largest
organelle• Double membrane• Contains
– Chromosomes
– Nucleolus
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Nuclear Envelope
• Separates nucleus from rest of cell
• Double membrane
• Has pores
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Nucleolus
• Dark Spot in nucleus
• Forms ribosomes, organelle that makes proteins
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DNA
• Hereditary material
• Chromosomes– tightly wound DNA
• Humans have 23 pairs
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Endoplasmic Reticulum
• Helps move substances within cells
• Network of interconnected membranes
• Two types– Rough endoplasmic reticulum– Smooth endoplasmic reticulum
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Rough Endoplasmic Reticulum
• Ribosome are attached
• Spreads throughout the cell
• The site of protein production
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Ribosome• Attached to the rough ER
– Make proteins– Attached to rough ER or free floating– Not surrounded my a membrane– There are many in a cell
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Smooth Endoplasmic Reticulum
• No attached ribosomes
• Makes lipids such as cholesterol– Carbohydrates– Lipids
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Golgi Apparatus
• Involved in synthesis of plant cell wall
• Packaging & shipping station of cell
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Golgi Apparatus Function
1. Prepares proteins for their jobs
2. Packages proteins into vesicles
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Vesicles
• Many inside the cell• After a protein is modified in the Golgi Apparatus
a vesicle pinches off containing the proteins• Transport substances• Tiny balls of membrane
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Lysosome
• Specialized Vesicle
• Full of enzymes, proteins that break down and recycle cell components like old proteins
• Tiny membrane ball
• Many
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Vacuoles
• Membrane bound storage sacs
• Plant cells have one large one
• Animal cells have many small ones
• Contents – Water– Food– wastes
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Energy Processing Organelles
• Release & store energy
• Types – Mitochondria
(release energy) – Chloroplasts
(store energy)
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Mitochondria
• Hundreds sometimes thousands
• Bound by double membrane
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Mitochondria
• Break down fuel molecules (cellular respiration)
– Glucose– Fatty acids
• Release energy– ATP
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ATP
• Adenosine triphosphate
• High-energy molecule
• Fuel for cellular processes
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Chloroplasts
• In plant cells
• Membrane bound
• Uses light to make glucose from CO2 and H2O
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Photosynthesis
• Takes place in the chloroplast
• Makes cellular food – glucose
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Review of Eukaryotic Cells
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Review of Eukaryotic Cells
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Cell Transport
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Cells Have Large Surface Area-to-Volume Ratio
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Molecule Movement & Cells
• Passive Transport
• Active Transport
• Endocytosis
(phagocytosis & pinocytosis)
• Exocytosis
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Passive Transport
• No energy required
• Move due to gradient– differences in concentration, pressure, charge
• Move to equalize gradient– High moves toward low
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Types of Passive Transport
1. Diffusion
2. Osmosis
3. Facilitated diffusion
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Diffusion
• Molecules move to equalize concentration
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Osmosis
• Special form of diffusion
• Fluid flows from lower solute concentration
• Often involves movement of water– Into cell– Out of cell
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Solution Differences & Cells• solvent + solute = solution
• Hypotonic– Solutes in cell more than outside– Outside solvent will flow into cell
• Isotonic– Solutes equal inside & out of cell
• Hypertonic– Solutes greater outside cell– Fluid will flow out of cell
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Facilitated Diffusion
• Differentially permeable membrane
• Channels (are specific) help molecule or ions enter or leave the cell
• Channels usually are transport proteins (aquaporins facilitate the movement of
water)• No energy is used
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Process of Facilitated Transport
• Protein binds with molecule
• Shape of protein changes
• Molecule moves across membrane
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Active Transport
• Molecular movement
• Requires energy (against gradient)
• Example is sodium-potassium pump
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Endocytosis
• Movement of large material– Particles– Organisms – Large molecules
• Movement is into cells
• Types of endocytosis– bulk-phase (nonspecific)– receptor-mediated (specific)
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Process of Endocytosis
• Plasma membrane surrounds material
• Edges of membrane meet
• Membranes fuse to form vesicle
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Forms of Endocytosis
• Phagocytosis – cell eating
• Pinocytosis – cell drinking
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Exocytosis
• Reverse of endocytosis
• Cell discharges material
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Exocytosis
• Vesicle moves to cell surface
• Membrane of vesicle fuses
• Materials expelled
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End Chapter 5