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Transcript
Biology Journal 11/10/2014 How is this picture like the endosymbiotic theory? Describe 4 pieces of evidence that support the endosymbiotic theory. Endosymbiosis Like all evolution, eukaryotes evolved through a series of small steps. This is a sweat gland attached to a hair follicle! 1. Which cell parts can we identify? 2. Which cells do you think… • Excrete water and lipids? • Make up the upper level of skin (epidermis)? • Make up the fatty, squishy layer of tissue under the skin? This is a cross-section of a leaf! How do some of the cells appear specialized for their job? 1. Which cell parts can we identify? 2. Which cells do you think… • Do photosynthesis? • Form a water-tight barrier? • Transport sugars and carbohydrates? Today! Get ready for your lab on osmosis. This lab will be counted as evidence. It will eventually all be put in your composition notebook. • Read the entire lab • Decide where you want to put it, and write your pre-lab questions, procedure, and materials. Do the homework questions for section 1.3 Is there any other practice you’ve skipped? You can do the Endosymbiotic Theory worksheet, the Cells, Cells, They’re made of Organelles worksheet, the Measuring Magnification worksheet… Today! Do your journal. Compare your answers with another classmate, and add to your journal anything they have that you didn’t think of. Get ready for your lab on osmosis. This lab will be counted as evidence. It will eventually all be put in your composition notebook. • Read the entire lab • Decide where you want to put it, and write your pre-lab questions, procedure, and materials. Do the homework questions for section 1.3 Is there any other practice you’ve skipped? You can do the Endosymbiotic Theory worksheet, the Cells, Cells, They’re made of Organelles worksheet, the Measuring Magnification Biology Journal 9/14/12 What molecule is the macromolecule DNA made out of? How did that molecule get its name? Biology Journal 9/20/10 What do ribosomes do? What other organelle are ribosomes often attached to? What does that organelle do? Biology Journal 11/21/13 How many cells do you think are in the average human’s body? Biology Journal 11/22/13 What are histones? What are chromosomes? What’s the difference between the DNA of a eukaryote and the DNA of a prokaryote? Biology Journal 11/27/13 The DNA of a prokaryote is called “naked.” Why is that? What’s different about the DNA of a eukaryote and a prokaryote? Topic 1: Cell Biology (15 hours) 1.2 Ultrastructure of cells: Eukaryotes have a much more complex cell structure than prokaryotes. Nature of science: Developments in scientific research follow improvements in apparatus—the invention of electron microscopes led to greater understanding of cell structure. Understandings: • Prokaryotes have a simple cell structure without compartmentalization. • Prokaryotes divide by binary fission. • Electron microscopes have a much higher resolution than light microscopes. • Developments in science, such as electron microscopy, can have economic benefits as they give commercial companies opportunities to make profits, but this can affect cooperation between scientists. Applications and skills: • Structure and function of organelles within exocrine gland cells of the pancreas and within palisade mesophyll cells of the leaf. • Drawing of the ultrastructure of prokaryotic cells based on electron micrographs: cell wall, pili and flagella, and plasma membrane enclosing cytoplasm that contains 70S ribosomes and a nucleoid with naked DNA. • Drawing of the ultrastructure of eukaryotic cells based on electron micrographs: plasma membrane enclosing cytoplasm that contains 80S ribosomes and a nucleus, mitochondria and other membranebound organelles are present in the cytoplasm. Some eukaryotic cells have a cell wall. • Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells. International-mindedness: Microscopes were invented simultaneously in different parts of the world at a time when information travelled slowly. Modern-day communications have allowed for improvements in the ability to collaborate, enriching scientific endeavour. Theory of knowledge: The world that we inhabit is limited by the world that we see. Is there any distinction to be drawn between knowledge claims dependent upon observations made by sense perception and knowledge claims dependent upon observations assisted by technology? Biology Journal 11/7/2014 A cell is 32 µm across. A student draws it as 250mm wide. What is the magnification? Show your work. A cell is 32 µm across. A student draws it as 250mm wide. What is the magnification? You don’t have to draw it, but you can if that helps! Measured length Actual size = Magnification 250 mm 32 µm = 32 µm = x 250000 µm Solve for x x 7800 times X= 7800 magnified Convert to the same 1000 µm units before you divide! 250 mm x 1 mm = 250000 µm Biology Journal 11/6/2014 What do you think could be the smallest things we can see with a light microscope? What do you think could be the smallest things we can see with an electron microscope? The kind of microscopes we have used are called light microscopes. A more powerful microscope is an electron microscope. What do you think these could be? 1.2 The Ultrastructure of Cells The invention of electron microscopes led to greater understanding of cell structure All organisms can be divided into two groups according to their cell structure. Organisms Prokaryotes Eukaryotes Germs! Smaller, simpler Cells like yours. Bigger, more complex Cell wall with peptidoglycan Cell wall with cellulose (plants), chitin (fungi), or no cell wall (animals) 70s ribosomes 80s ribosomes Cell membrane on inside of cell wall; no organelles Cell membrane on inside of cell wall and all throughout cell surrounding organelles Prokaryotes have a simple cell structure without compartmentalization and divide by binary fission. Nucleoid Region where naked DNA can be found; may have plasmids (loops of “extra” DNA, which can introduce new genes) Cytoplasm Jelly-like substance where many molecules are stored and reactions take place Pili Allows cells to connect to each other and exchange DNA (sexual reproduction) Flagella Whip like structure that allows the cell to move Cell Membrane Made out of phospholipids; controls what enters and leaves cell Cell Wall Made out of peptidoglycan (mesh of amino acids and sugars) Ribosomes They make protein; prokaryotes have 70S ribosomes Drawing of the ultrastructure of prokaryotic cells based on electron micrographs: cell wall, pili and flagella, and plasma membrane enclosing cytoplasm that contains 70S ribosomes and a nucleoid with naked DNA. Drawing of the ultrastructure of prokaryotic cells based on electron micrographs: cell wall, pili and flagella, and plasma membrane enclosing cytoplasm that contains 70S ribosomes and a nucleoid with naked DNA. A Terrible Drawing… Too light Unlabeled Messy Parts are indistinguishable Tiny A Good Drawing… • • • • • Good use of space Clear strong lines Label lines are straight Labels clearly written Scale bar if appropriate • • Lines touch the labeled structure No unnecessary shading or coloring Nucleus DNA contained in a membrane Mitochondria Makes energy for the cell by doing cellular respiration Vacuole Large compartment for storage of water or other molecules Ribosomes They make protein; eukaryotes have 80S ribosomes; sometimes they are found on ER Endoplasmic Reticulum Transports molecules; can have ribosomes attached to it (rough) or none (smooth) Golgi Complex Makes vesicles for molecules to enter or leave the cell in large groups Cytoplasm Jelly-like substance where many molecules are stored and reactions take place Chloroplast Makes glucose through photosynthesis Cell Wall In plant cells, it is made out of cellulose (a carbohydrate); In fungi, it is made out of chitin (a carbohydrate); Animal cells don’t have one Drawing of the ultrastructure of eukaryotic cells based on electron micrographs: plasma membrane enclosing cytoplasm that contains 80S ribosomes and a nucleus, mitochondria and other membrane-bound organelles are present in the cytoplasm. Some eukaryotic cells have a cell wall. 10µm Plasma membrane Mitochondria Free 80S ribosomes Lysosomes Cytoplasm Nucleus Golgi apparatus Rough Endoplasmic Reticulum 10µm Identify the structures in these false-colored microscopic images Cell membrane Cell wall Cytoplasm (the darker spheres are ribosomes) Pili Flagella Nucleoid region (where DNA is located) Identify the structures in this false-colored microscopic image of a human liver cell Cytoplasm Mitochondria Ribosomes (free) Plasma membrane Nucleus Endoplasmic Reticulum (rough) Lysosome Identify the structures in this microscopic image of a plant cell (not false colored) Chloroplast Vacuole Cytoplasm (little dots are ribosomes) Cell Wall Mitochondrion Nucleus Plasma membrane This is a sweat gland attached to a hair follicle! 1. Which cell parts can we identify? 2. Which cells do you think… • Excrete water and lipids? • Make up the upper level of skin (epidermis)? • Make up the fatty, squishy layer of tissue under the skin? This is a cross-section of a leaf! How do some of the cells appear specialized for their job? 1. Which cell parts can we identify? 2. Which cells do you think… • Do photosynthesis? • Form a water-tight barrier? • Transport sugars and carbohydrates? Structure and function of organelles within exocrine gland cells of the pancreas and within palisade mesophyll cells of the leaf. Structure and function of organelles within exocrine gland cells of the pancreas and within palisade mesophyll cells of the leaf. What is its function? Structure and function of organelles within exocrine gland cells of the pancreas and within palisade mesophyll cells of the leaf. Structure and function of organelles within exocrine gland cells of the pancreas and within palisade mesophyll cells of the leaf. Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells. Nucleus • Contains the DNA • Has a nuclear membrane In most cells the nucleus is the easiest organelle to see White blood cells Muscle Cells Red blood cells, these don’t have a nucleus Nucleus means “middle” it’s used in many ways in science Mitochondria • Makes energy for the cell through a reaction called cellular respiration • uses up oxygen and sugar for fuel What kinds of cells might need a lot of energy? Muscle cells have lots of mitochondria What other kinds of cells might need a lot of energy? Neurons (brain and nerve cells) use energy to send electrical signals What other kinds of cells might need a lot of energy? What kinds of cells don’t need a lot of energy? Bone cells Fat cells (adipose tissue) Ribosomes • Make protein through translation • Made out of rRNA Endoplasmic Reticulum • Membranes that send proteins to where they need to go using chemical signals – Rough E. R. has ribosomes on it – Smooth E. R. does not have ribosomes on it. E. R. is like a postal carrier, sending proteins to where they are supposed to go. Endoplasmic Reticulum • Rough and smooth are connected. • The Rough has ribosomes on it like rhinestones on a shirt. Golgi Complex / Apparatus • Packages up molecules in a sac called a vesicle and sends them to where they need to go using chemical signals Camillo Golgi, winner of Nobel prize in medicine in 1906; winner of world’s sexiest moustache competition in 1907. Vacuole • A sack for storing water and nutrients. Like a storage tank. Most plant cells have 1 large vacuole Why might plant cells store lots of water in vacuoles, but animal cells don’t? Chloroplast • Uses sunlight to make sugar molecules (photosynthesis) • Contains green pigments (chlorophyll) • Plants only Lysosome • Breaks down and digests large pieces of food, or unneeded organelles, using acids and enzymes • Animal cells tend to have many. Plant cells rarely do. In what tissues might we find a lot of lysosomes? Digestive Cells What other cells might we find a lot of lysosomes? Bacteria trying to out-run a white blood cell. If the white blood cell gobbles up a bacteria, it sends the bacteria to a lysosome to be digested. Cytoplasm • The jelly-like substance that takes up the space inside a cell. Cytoplasm is chalked full of molecules that the cell uses. Cell Membrane ( aka Plasma membrane) • The “skin” of a cell. Controls what enters and leaves through transport proteins. Cell Membrane ( aka Plasma membrane) • It’s made out of two layers of lipids called phospholipids. Plant Cell Wall • Hard structure made out of carbohydrates. • Makes plant cells strong and sturdy, but prevents them from moving • Plants only! Bacterial Cell Wall • A tough structure made out of peptidoglycan (a protein-carbohydrate substance) • In some bacteria, this cell wall can be stained and identified (called gram-positive bacteria), and in some bacteria the cell wall can’t (called gram-negative bacteria) Flagella • A whip-like tail for swimming through liquid. There are 2 basic kinds of cells 1. Prokaryotes • Bacteria • Have 1 circular piece of DNA • No organelles! • Small and simple, so they can multiply fast! There are 2 basic kinds of cells 2. Eukaryotes • Have many pieces of linear DNA (in lines) • Have organelles! • Bigger and more complex • Anything multicelluar is a eukaryote (including you) Eukaryotes are about 100 times bigger than prokaryotes Biology Journal 11/25/2013 Compare and contrast eukaryotes and prokaryotes in a Venn diagram. Eukaryotes Both Prokaryotes Biology Journal 11/25/2013 Compare and contrast eukaryotes and prokaryotes in a Venn diagram. Eukaryotes Both Prokaryotes •Large and more complex •Have a cell membrane and cytoplasm •Small and simple •Has a nucleus and organelles •Reproduce through asexual cell division •Lacks a nucleus and lacks organelles •DNA is linear and in many pieces (chromosomes) Have ribosomes (but they •DNA is circular and in are different) one piece (usually) •Cells divide through mitosis •Cells divide through binary fission •Have 80s ribosomes •Have 70s ribosomes •Attaches and transfers DNA through pili Biology Journal 11/26/2013 Compare and contrast plant and animal cells in a Venn diagram. Plant Both Animal Biology Journal 11/26/2013 Compare and contrast plant and animal cells in a Venn diagram. Plant Both Animal •Often are high in lysosomes •Have chloroplasts •Are eukaryotes •Has a plant cell wall •Have other organelles in •Can have great common (mitochondria, ability to move ER, golgi bodies…) •Has a large vacuole •Are similar in size •No / very limited ability to move •Cells asexually reproduce through mitosis Extracellular Components – parts outside of the cell The cell wall of plants •Gives the cell shape •Holds the cell up against gravity •Prevents it from exploding from too much water Glycoproteins of animals •Made out of carbohydrates attached to proteins •Gives the cells adhesion •Anchors the cell to surrounding cells •Allow for movement On your notecard, write… 1. 2. 3. 4. 5. Your name on the card One question that’s a definition One question that’s a drawing One question that’s an explanation Write the answers to these on the backside Sarah Smith hr.1 What does flagella do? What’s this thing? Why do eukaryotes have to do mitosis, but prokaryotes don’t?