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1 st Quarter Biology STAR Review
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Scientific Method 1.Observation is made using one of your 5 senses. 2.A hypothesis is a proposed explanation for the way something functions. 3.A prediction forecasts the outcome of an experiment if the hypothesis is true. -
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Scientific Method cont. 4. An experiment tests the hypothesis and the predictions. 5. Data are analyzed and conclusions made. 6. Communication to peers and public.
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Enzymes Speed up reactions without altering the reaction Must have substrate match perfectly in order to become active Very sensitive to temperature, pH, and salinity
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Cell Theory 1. all living things are composed of 1 or more cells 2. cells are the basic units of structure and function in an organism 3. cells come only from the reproduction of existing cells
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Prokaryotic cells cells without a nucleus (bacterial cells)
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Eukaryotic cells cells with a nucleus (animal cells, plant cells)
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Organelles Internal organization – cells have internal structures that carry out their life processes Organelles – a cell component that performs specific functions for a cell
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Organelles In animal cells…
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Cell Membrane Composed of a lipid bilayer –contains several kinds of proteins that “float” along the bilayer Selectively permeable –some things can easily cross the membrane and others cannot cross at all
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Cytoplasm the jello between the cell membrane and organelles
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mitochondria transfers energy from organic compounds to ATP (stored energy) Has two membranes more mitochondria in cells that use the most energy –Ex. Muscle and heart cells
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Ribosome makes proteins Found in the cell: Attached to the Endoplasmic Reticulum Free floating in cytoplasm
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Endoplasmic Reticulum – Transport system that moves materials which have been made throughout the cells Like an assembly line
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Golgi Apparatus looks a lot like ER, except has vesicles modifies proteins for export by the cell packages substances produced by the cell
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Protein Transport
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Lysosome digests molecules, old organelles, and foreign substances (“clean up crew”)
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Cilia and Flagella hair like organelles that extend from the surface of the cell assist in movement
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Nucleus Control center of cell, contains DNA, creates ribosomes
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More Organelles… In plants…
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Plant Cells plants contain most of the same organelles as other eukaryotic cells plus 3 additional ones –Cell Walls –Vacuoles –Chloroplasts
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Cell Wall a rigid layer on the outside of the cell membrane supports and protects the plant composed of long chains of cellulose
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Vacuoles filled with water and stores enzymes and metabolic wastes Much larger than animal vacuoles
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Chloroplast convert sunlight to energy like mitochondria, they have two membranes chloroplast – contain sacs called thylakoids –contain pigments that give the flower/plant their color
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Multicellular Organization
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Levels of organization Tissues – groups of cells that carry out a specific function Organs –several types of tissues that interact to perform a specific function Organ system – a group of organs that work together to perform a set of related tasks
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Transport Moving materials into or out of the cell through the cell membrane
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Passive Transport Does NOT require any energy Moves from an area of high to low concentration 3 kinds –Diffusion –Osmosis –Facilitated Diffusion
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Diffusion Movement of molecules from an area of high concentration to an area of low concentration
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Osmosis Water moves across a membrane from an area of high concentration to an area of low concentration
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Facilitated Diffusion Materials move through channels in the membrane
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Active Transport DOES require energy (ATP) Moves from an area of low to high concentration
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Photosynthesis Plants use sunlight to make energy (glucose)… 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 12 H 2 O in 6 CO 2 in C 6 H 12 O 6 out 6 H 2 O out Chlorophyll Enzymes Radiant Energy In 6 O 2 out
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Cellular Respiration C 6 H 12 O 6 + 6 O 2 6CO 2 + H 2 O +{energy ATP} Glucose + Oxygen Carbon Dioxide +Water + ATP
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Reproduction
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Why do cells divide? In eukaryotic cells –Repair Replace lost or damaged tissue –Growth Babies grow into adults –Sexual reproduction –Asexual reproduction Earthworms don’t have a sexual partner –Development Growing a fetus
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Bacteria Reproduction Binary Fission –They copy DNA and split in half –Asexual reproduction
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Eukaryote Reproduction
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Chromosome DNA coiled up so that it can move easily during reproduction
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Two Kinds of Eukaryotic Cells –Diploid Body cells Contain 46 chromosomes Reproduce by mitosis –Haploid Sex cells Contain 23 chromosomes Reproduce by meiosis
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Two Kinds of Chromosomes –Autosomes Chromosome that do not determine gender Chromosomes 1- 22 on karyotype –Sex Chromosomes X and Y Female XX Male XY
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The Cell Cycle Interphase: Cell grows, DNA copied Prophase: Nucleus disappears, DNA condenses, prepare to divide Metaphase: Chromosomes line up in middle Anaphase: Chromosomes separate Telophase: Nucleus reappears, chromosomes unravel Cytokinesis: Two daughter cells separate
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Mitosis
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Mitosis Swimming Pool
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