Presentation on theme: "Cells Basic units of Life.. Cells—Structure and Function B2.4 g -- Explain that some structures in the modern eukaryotic cell developed from early prokaryotes,"— Presentation transcript:
Cells Basic units of Life.
Cells—Structure and Function B2.4 g -- Explain that some structures in the modern eukaryotic cell developed from early prokaryotes, such as mitochondria, and in plants, chloroplasts. Prokaryotic – cells lacking a membrane bound nucleus—ex. Bacteria Eukaryotic – cells having a membrane bound nucleus among other organelles:
Cells –Structure and Function 1. A. endosymbiotic theory—proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms. 1. B. organelles – specialized structures inside eukaryotic cells
Cells --Structure and Function Relate cell parts/organelles to their function. ( B2.5i) 2. A. organelles – specialized structures inside eukaryotic cells
Cells – Structure and Function 2.A.1. nucleus – contains cell’s DNA, control center of cell, all cells of an organism have the same DNA --advantage of having DNA within a membrane= cell can do more than one task at a time --prokaryotes can only perform one task at a time, i.e. make proteins, digest, or move.
Cells – Structure and Function 2.A.1. a. structures of the nucleus: nucleolus – dense region within nucleus, site of ribosome synthesis chromatin – granular material inside nucleus, DNA bound to protein, during cell division will form into chromosomes chromosomes—distinct, threadlike structures that contain genetic material passed from one generation to the next. nuclear envelope—separates the nucleus from the rest of the cell. nuclear pore – small openings in the nuclear envelope that allow materials to enter and leave the nucleus.
Cells – Structure and Function 2.A.2. Ribosome – site of protein synthesis, found in both prokaryotes and eukaryotes 2.A.3. Endoplasmic reticulum – system of channels in which proteins (rough E.R) and lipids (smooth E.R.) are made 2.A.4. Golgi apparatus (complex)—rearranges, packages, and ships proteins in vesicles from the ER for specific uses inside and outside (secretion/exocytosis) of cell
Fig. 5.47 Electron micrograph showing Smooth and Rough Endoplasmic Reticulum, Peroxisomes (P) and Mitochondria (M).
Cells – Structure and Function 2.A.5. Lysosomes – low pH and have powerful enzymes that digest molecules INTERESTING FACT: lysosomes are used in tadpole development to dissolve the tissues that make up the tadpole tail so that the legs of the adult frog can form 2.A.6. peroxisomes – contain enzymes that result in the production of hydrogen peroxide, which will be turned into water and oxygen, used to break down lipids
Cells – Structure and Function 2.A.7. vacuoles – more common in plants than animals used for water, sugar, and salt storage
Cells – Structure and Function 2.A.8. chloroplasts – thought to have come from endosymbiosis of photosynthetic bacteria within another bacterial cell -- site of photosynthesis in plants and some algae -- capture energy from the sun and convert water and carbon dioxide into high energy sugars and oxygen
Cells – Structure and Function 2.A. 9. mitochondria – thought to have come from endosymbiosis of energy producing bacteria within another bacterial cell -- site of cellular respiration in all eukaryotic organisms --powerhouse of cell – convert glucose and oxygen into ATP, water, and carbon dioxide
2.B. other cell structures that are not organelles: 2.B.1. cytoskeleton – network of tubules and filaments that give cell its structure and assist in movement 2.B.2. centrioles – tubules that assist chromosome movement during cell division 2.B.3. cilia and flagella – structures that aid in the movement of the cell. 2.B.4. cytoplasm – gel that fills the cell, allows for materials to diffuse from one side of cell to other 2.B.5. plasma membrane – separates the cell from the environment
Plant Vs. Animal Cells 3. Compare and contrast plant and animal cells. ( B2.5g) **Compare and contrast the organelles found in plant and animal cells. **Make a three dimensional model of a typical plant or animal cell. Include all of the structures listed above. **Write an analogy that describes each organelle or cell structure as a part of a factory.
StructureAnimal CellPlant Cell NucleusXX RibosomesXX Endoplasmic reticulum (rough and smooth)XX CytoplasmXX MicrotubuleXX Central vacuole X PeroxisomeXX MitochondrionXX Chloroplast X Plasma membrane (cell membrane)XX Cell wall X Golgi ApparatusXX CentrioleX Cilia and FlagellaXX
Endosymbiotic Theory 4. Explain that some structures in the modern eukaryotic cell developed from early prokaryotes, such as mitochondria, and in plants, chloroplasts (B2.4 g ). Prokaryotic – cells lacking a membrane bound nucleus—ex. Bacteria Eukaryotic – cells having a membrane bound nucleus among other organelles:
Endosymbiotic Theory 4. A. endosymbiotic theory—proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms. 4.B. organelles – specialized structures inside eukaryotic cells B2.4 g
Cell Membrane 5. Explain the role of cell membranes as a highly selective barrier (diffusion, osmosis, and active transport). ( B2.5h) 5.A. cell membrane – flexible barrier that surrounds cell Controls what enters and leaves the cell
Cell Membrane 5.B. Bilipid layer – two layered sheet 5.B.1. Flexible yet strong 5.B.2. Mosaic – different pieces sitting side by side to form a larger structure Phospholipid – hydrophobic tails and hydrophilic heads (main component) Proteins – often act as channels for substances to enter and leave cell – Cell recognition – Enzyme excretion Carbohydrate chain – identification marker for the cell Cholesterol – helps strengthen membrane
Cell Membrane **Make a model of a typical animal cell that demonstrates cell membrane structures. --include a description of each structure and a key on a separate sheet of paper
Cell Membrane 5.B.3. Selectively permeable – some substances can move across the membrane others cannot 5.B.4. Transport – moving material across the cell membrane 5.B.4.a. Passive – no energy required http://www.northland.cc.mn.us/biology/biolo gy1111/animations/passive1.swf
Cell Membrane Diffusion – random movement of particles from high concentration to low concentration – Solution: a mixture of solvent and solute » Solute – dissolved material » Solvent – material that does the dissolving (usually water for living things) – Concentration gradient – molecules move from high to low concentration » Oxygen – into cell » Carbon dioxide – out of cell
Cell Membrane Osmosis: diffusion of water across a selectively permeable membrane—high concentration to low concentration – Isotonic solution – solute concentration equal on both inside and outside of cell when cell is placed in solution » No net movement of water in or out of cell » Cells have a.9% NaCl solution so IV bags have a.9% NaCl solution – Hypertonic solution – solution outside the cell has a higher concentration of solutes than the cell » Water moves out of the cell » Fresh water fish in salt water » Cell shrinks – crenates – Hypotonic solution – solution outside the cell has a lower concentration of solutes than the cell » Water enters the cell » Salt water fish in fresh water » Cell swells – causes turgor pressure (keeps plant cells rigid)
Cell Membrane 5.B.4.b. Facilitated diffusion – movement of particles from high concentration from high concentration to low concentration through a channel – Large and charged molecules: polar molecules (glucose) and ions (amino acids)
Cell Membrane 5.B.4.c.Active – requires energy – low concentration to high concentration Against the concentration gradient Requires a channel and energy (ATP) » Types: Exocytosis – carry macromolecules out of cell Endocytosis – bring macromolecules into cell Phagocytosis – taking large substances into cell Pinocytosis – liquids and small particles into cell http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapt er2/animation__how_the_sodium_potassium_pu mp_works.html http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapt er2/animation__how_the_sodium_potassium_pu mp_works.html
Cell Membrane – Sodium potassium pump: » The same carrier protein moves sodium ions (Na+) to the outside of cell and potassium ions (K+) to the inside of cell » Uses ATP to change shape of channel » Three sodium ions are carried outward for every two potassium ions carried inward causing the inside of the cell to be negatively charged compared to the outside.
Cell Membrane **Contrast movement by facilitated diffusion with movement by active transport