Bellwork Do you agree or disagree with this
Bellwork Do you agree or disagree with this statement? All plant cells are square and all animal cells are round WHY?
Biology CELLS CELL THEORY
Cell Discovery Robert Hook (1665) Created a crude microscope Observed Tiny He the first cells (cork) hollow compartments named them cells
Hooke’s equipment
Better Microscope Anton Von Leeuwenhoek (1674) Created See better lenses greater detail Named them “animalcules”
Leeuwenhoek’s equipment
Plant Cells Matthias Schleiden (1838) Discovered that plants are made of cells
All Living Things Theodor Schwann (1839) Proposed BUT that all living things are made of cells he believed in spontaneous generation
Preexisting Cells Rudolf Virchow (1855) Proposed that all living cells come from other cells This means all living things come from other living things
Modern Cell Theory 1. All organisms are made up of cells 2. All existing cells are produced by other living cells 3. The cell is the most basic unit of life
Think – Pair - Share Virus - an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host. Answer the following question based on the above description and your knowledge of Biology. Are Viruses living? Why/Why not?
Understanding Check “ 3 -3 -3” Name the 3 parts of the cell theory Name 3 structures that all living cells have Give 3 examples of different types of cells
Bellwork Do you agree or disagree with the following statement? Why/Why Not? All cells have the same organelles in the same amounts Ex. Muscle cells have the same number of mitochondria as skin cells
ALL Cells have… Plasma membrane (“cell” membrane) Cytoplasm Ribosomes Genetic Material (DNA)
Prokaryotic vs Eukaryotic cells
Prokaryotic Cells Small Simple NO NUCLEUS NO complex organelles Ex. All bacteria (streptococcus, staphylococcus, E. coli, Salmonella)
Prokaryotic Cell Structures: Cell wall Cell membrane Cytoplasm Ribosomes DNA Plasmid Flagella
Eukaryotic Cells Larger More complex HAVE A NUCLEUS HAVE COMPLEX ORGANELLES Ex- all complex multicellular organisms like plants and animals
Eukaryotic Cell Structures Cell wall Rough Endoplasmic Reticulum Vacuoles Cell membrane Smooth Endoplasmic Reticulum Chloroplasts Cytoplasm Nucleolus Nucleus Chromatin Cilia Nuclear envelope Microtubules Flagella Ribosomes Microfilaments Golgi Apparatus Mitochondria Lysosome
Under the microscope
Understanding Check 3 – 2 - 1 Name 3 structures found in ALL CELLS Name 2 structures found only in Eukaryotic cells Name 1 structure found only in Prokaryotic cells
BELLWORK Determine if each structure is found in Prokaryotic cells, Eukaryotic cells or Both. Place a P, E or B next to each structure: Cell wall Cell membrane Ribosomes Cytoplasm DNA Golgi. Apparatus Mitochondria Chloroplasts Nucleus Centrioles
Eukaryotic Organelles Ø Cell Membrane – aka plasma membrane, boundary between a cell and the outside environment; controls what passes in and out of a cell
Ribosomes proteins – tiny organelles that make
Cytoplasm – jellylike substance that contains dissolved materials and organelles
Nucleus – where DNA is stored in eukaryotic cells. Control center! Nuclear Envelope – double membrane surrounding the nucleus Nucleolus – dense region within the nucleus where ribosomes are made Chromatin – DNA strands and protein loosely packed in the nucleus when a cell is not dividing (interphase)
Smooth Endoplasmic reticulum (ER) – network of thin, folded membranes that produce, process, and distribute proteins Rough Endoplasmic reticulum (ER) – same as smooth ER but with ribosomes attached to the membrane
Golgi apparatus – stacks of layered membranes that process, sort and deliver proteins to their destination
Bellwork Compare and contrast the cell membrane and nuclear envelope
Mitochondria – supply energy to the cell in a usable form by producing ATP chemical energy
Centrioles – cylinder shaped organelles made of short microtubules. Produce the spindle for cell division
Vacuoles – fluid-filled sacs used for storing materials needed by the cell (ex water, ions, enzymes)
Lysosomes – membrane bound organelles that contain enzymes. Break down damaged cell parts and defend the cell from invading microbes
Cytoskeleton – network of protein fibers that crisscross a cell to provide structure and support where needed. Constantly change shape based on the cell’s needs 3 types of cytoskeletal elements
3 types: a. Microtubules – long hollow tubes, give cell its shape, tracks for movement b. Intermediate filaments - give a cell strength c. Microfilaments – smallest, tiny threads that help cells move
Plant cell structures…. Cell wall – strong cell wall found in plant, algae, fungi and bacteria Rigid layer that gives support, protection and shape to the cell
Chloroplasts – organelles that carry out photosynthesis Convert solar energy into food energy
Bellwork Explain how mitochondria and chloroplasts work together to provide a cell with a usable source of energy. Be as specific as you can
Membrane Movement Cell membrane (plasma membrane): Boundary between cell and outside environment Controls what enters and leaves a cell
Fluid Mosaic model Cell Membrane - Composed of phospholipids and proteins Double phospholipid layer with proteins embedded CM is flexible (NOT RIGID) The molecules slide past one another like a liquid
Selective Permeability CM is selectively permeable It allows some, not all materials to cross This allows a cell to maintain homeostasis There are many different ways for molecules to cross the membrane
Passive Transport Passive transport – movement of molecules across a cell membrane WITHOUT ENERGY input from the cell Diffusion – movement of molecules from a region of higher concentration to lower concentration
Concentration gradient – difference in concentration of a substance from one location to another Molecules diffuse DOWN their concentration gradient Molecules diffuse until they reach dynamic equilibrium (same amount of molecules moving both ways across the membrane)
Passive Transport Osmosis – diffusion of water molecules across a membrane from higher concentration of water to lower concentration of water The more dissolved particles in a solution the less water there is
Tonicity - The ability of a solution to make water move into or out of a cell by osmosis
Tonicity Isotonic – when the solution that a cell is placed in has the same concentration of dissolved particles as the cell. No net movement of water but molecules still move in and out
Tonicity Hypertonic – when a solution has a higher concentration of dissolved particles than a cell (and less water than the cell). Water flows OUT of the cell. Cell shrinks!
Tonicity Hypotonic – when a solution has a lower concentration of dissolved particles than a cell (and more water than the cell). Water flows INTO the cell. Cell bursts!
Facilitated Diffusion Facilitated diffusion – diffusion of molecules across the cell membrane through transport proteins Passive transport because no energy used Molecules still move DOWN their concentration gradient
Facilitated diffusion
Active Transport Active transport – drives molecules across a membrane from lower concentration to higher concentration This USES ENERGY in the form of ATP! Uses special transport proteins called pumps Ex: sodium-potassium pump
Active Transport
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