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Transcript
Prokaryotic Cells Vs. Eukaryotic Cells Now that we have learned how living things are organized what’s next? We will learn more about the lowest level of organization: cells What is the first thing that we need to know about cells? All cells fall into one of the two major classifications of either prokaryotic or eukaryotic. What’s the difference between prokaryotes and eukaryotes? Prokaryotic cells were here first and for billions of years were the only form of life on Earth. All prokaryotic organisms are unicellular Eukaryotic cells appeared on earth long after prokaryotic cells but they are much more advanced. Eukaryotic organisms unlike prokaryotic can be unicellular or multicellular. Glow in the dark squid… how does it do that? Vibrio fischeri Glow in the dark bacteria Helps it survive in the ocean Lives in fish and other marine life Let’s Take a Look at the Characteristics of Prokaryotes Prokaryotes are the simplest type of cell. Oldest type of cell appeared about four billion years ago. Prokaryotes are the largest group of organisms Prokaryotes unicellular organisms that are found in all environments. Let’s Take a Look at the Characteristics of Prokaryotes Prokaryotes do not have a nuclear membrane . Their circular shaped genetic material dispersed throughout cytoplasm. Prokaryotes do not have membrane-bound organelles . Prokaryotes have a simple internal structure. Prokaryotes are smaller in size when compared to Eukaryotes. Shapes of Prokaryotes Cocci = spherical (round) Bacillus = (rod shaped) Spirilla = helical (spiral) What do prokaryotic cell look like? Now let’s take a look at the characteristics of eukaryotes Eukaryotic cells appeared approximately one billion years ago Eukaryotes are generally more advanced than prokaryotes Nuclear membrane surrounds linear genetic material (DNA) Is there more? Yes!!! Unlike prokaryotes, eukaryotes have several different parts. Eukaryote’s organelles have coverings known as membranes. Eukaryotes have a complex internal structure. Eukaryotes are larger than prokaryotes in size . What do eukaryotic cells look like? Mitochondria Nucleus Cytoplasm Golgi Complex Endoplasmic Reticulum Cell Membrane How do the differences line up? Prokaryotes Organelles lack a membrane Eukaryotes Organelles covered by a membrane Ribosomes are the only organelles Multiple organelles including ribosomes Genetic material floats in the cytoplasm (DNA and RNA) Membrane covered Genetic material How do the differences line up? Prokaryotes Circular DNA Eukaryotes Linear DNA Unicellular May be multicellular or unicellular Cells are smaller in size Cells are larger in size Has larger number of organisms Has smaller number of organisms How do the differences line up? Prokaryotes Appeared 4 billion years ago Eukaryotes Appeared 1 billion years ago How do the similarities line up? Lets See!!! Both types of cells have cell membranes (outer covering of the cell) Both types of cells have ribosomes Both types of cells have DNA Both types of cells have a liquid environment known as the cytoplasm Your turn: Make a Venn Diagram outlining the similarities and differences between prokaryotes and eukaryotes You may use your book and/or consult your teammate Robert Hooke Used a compound microscope and viewed a slice of cork. He saw little box structures and called them cells. He used this name because it reminded him of little rooms that monks lived in. Anton Van Leeuwenhoek Was the first to see living organisms and called them animalcules. Used the first simple light microscope. Matthias Schleiden First to see living plant cells and determined that plants are also made of these tiny structures called cells. Theodor Schwann Viewed animal tissue and concluded that animals are also made of these tiny structures called cells. Rudolf Virchow He was the scientist that said cells can only be produced by other living cells. The Cell Theory 1. 2. 3. All Organisms are composed of one or more cells. The cell is the basic unit of structure and organization of organisms. All cells come from other living cells. Cells Organelles are membrane-bound cell parts Mini “organs” that have unique structures and functions Located in cytoplasm Cell Structures Cell membrane delicate lipid and protein skin around cytoplasm found in all cells Nucleus a membrane-bound sac evolved to store the cell’s chromosomes(DNA) has pores: holes Nucleolus inside nucleus location of ribosome factory made or RNA mitochondrion makes the cell’s energy the more energy the cell needs, the more mitochondria it has Ribosomes build proteins from amino acids in cytoplasm may be free-floating, or may be attached to ER made of RNA Endoplasmic reticulum may be smooth: builds lipids and carbohydrates may be rough: stores proteins made by attached ribosomes Golgi Complex takes in sacs of raw material from ER sends out sacs containing finished cell products Lysosomes sacs filled with digestive enzymes digest worn out cell parts digest food absorbed by cell Centrioles pair of bundled tubes organize cell division Cytoskeleton made of microtubules found throughout cytoplasm gives shape to cell & moves organelles around inside. Structures found in plant cells Cell wall very strong made of cellulose protects cell from rupturing glued to other cells next door Vacuole huge water-filled sac keeps cell pressurized stores starch Chloroplasts filled with chlorophyll turn solar energy into food energy How are plant and animal cells different? Structure cell membrane nucleus nucleolus ribosomes ER Golgi centrioles cell wall mitochondria cholorplasts One big vacuole cytoskeleton Animal cells Yes Yes yes yes yes yes yes no yes no no yes Plant cells yes yes yes yes yes yes no yes yes yes yes Yes Eukaryote cells can be multicellular The whole cell can be specialized for one job cells can work together as tissues Tissues can work together as organs Advantages of each kind of cell architecture Prokaryotes Eukaryotes simple and easy to grow can specialize fast reproduction multicellularity all the same can build large bodies What do all these have in common? Specialized Cells Learning Objectives: Learning Activities: 1. All must be able to 1. What is the picture? describe with examples, 2. Discuss what is a how cells are specialised specialised cell to perform different 3. Powerpoint showing functions. different specialised cells 2. Most should be able to 4. Worksheet state how cells group 5. Quiz on plant and animal together to form tissues. cells 3. Some could state how specific cells are adapted to their function. WHAT IS A SPECIALIZED CELL? Plants and animals consist of many cells and so are known as multicellular They contain many different types of cells. Each type of cell is designed to carry out a particular job or function. This is known as cell specialism Not all cells look the same. Some cells have a special shape and features to help them do a certain job. SPERM CELL Head contains enzymes & nucleus Designed to Fertilise eggs. Found in the Testes Tail A sperm is small and has a long tail that provides movement so it can swim and find an egg cell. The head contains enzymes which allow it to digest into an egg cell and join with it. EGG (OVUM) CELL Cytoplasm containing yolk Designed Found to be Fertilised. in the Ovaries. An egg cell is large and bulky. Contains Layer of jelly Nucleus yolk which provides a large food store for the new cell being formed. PALISADE CELL Designed for Photosynthesis Found Nucleus in the top of a leaf Tall and has a large surface area to absorb water and minerals. Packed with chloroplasts to help make plant food. Chloroplasts CILIATED CELL Nucleus Designed to stop Lung Damage They line all the air passages (trachea, bronchi & bronchioles) in the lungs. They have tiny hairs called cilia. Hairs sweep mucus with trapped dust and bacteria back up the throat. cilia ROOT HAIR CELL Designed for absorbing. Vacuole •Thin cell wall makes it easy for minerals to pass through. thin cell wall •Has a large surface which helps it to absorb water and minerals. Cell membrane •Found in a plant root. NERVE CELL (NEURONE) Nucleus •They are long •They have connections at each end •Can carry electrical signals •Their job is to carry nerve impulses to different parts of the body. RED BLOOD CELL •Designed to carry oxygen •Found in blood. •Large surface area, for oxygen to pass through. •Contains haemoglobin, which joins with oxygen. •Has no nucleus How do animal cells move? Some can crawl with pseudopods Some can swim with a flagellum Some can swim very fast with cilia Pseudopods means “fake feet” extensions of cell membrane example: ameoba Flagellum/flagella large whiplike tail pushes or pulls cell through water can be single, or a pair Cilia fine, hairlike extensions attached to cell membrane beat in unison