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Chapter 3 From a Cell to an Organism. The Cell Cycle and Cell Division. The Cell Cycle. Cell Cycle – a cycle of growth, development, and division. - replace old, damaged cells with new Two Phases Interphase – growth and development (most of life)
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The Cell Cycle • Cell Cycle – a cycle of growth, development, and division. - replace old, damaged cells with new • Two Phases • Interphase – growth and development (most of life) - rapid growth and replication (organelles) - copy DNA - prepare for cell division • Mitotic Phase – reproduction (short period of life) - two new cells are created - 2 stages - mitosis – nucleus divides - cytokinesis – cytoplasm divides • Length of cell cycle - depends on type of cell • 8 min, one year, or 24 hours
Interphase • Makes up most of cell cycle • Rapid growth • Cell increases in size • Cellular activities (making proteins) • Copy DNA (chromatin-long thin strands) • Prepare for cell division • Phases • G1 = Growth and Cellular Functions; Organelle replication • Longest Stage • Some cells stay in this stage (nerve cells) • S = Growth and Chromosome Replication; Organelle replication • DNA copied – 2 strands of DNA ensures each new cell will get same info. • Chromosomes form from sister chromatids held together by a centromere • G2 = Growth and Cellular Functions; Organelle replication • Stores Energy for Mitosis
The Mitotic Phase • Two Stages • Mitosis – nucleus and contents divide • Sister chromatids separate(20 chromatids – 10 different chromosomes) • Each new cell has exactly the same information • Phases of Mitosis • Prophase – copied DNA condenses into chromosomes - nucleolus disappears; nuclear membrane breaks down - spindle fibers form • Metaphase – spindle fibers pull/push chromosomes to middle of cell • Anaphase – sister chromatids separate - spindle fibers shorten pulling chromatids to opposite sides of the cell - cell begins to lengthen • Telophase – nuclear membrane forms around the chromatin - chromosomes unwind - spindle fibers break down - two identical nuclei form • Cytokinesis – cytoplasm divides (animal = furrow / plant = cell plate) • Daughter Cells – the 2 new cells that result from mitosis and cytokinesis
Cell Division Animation http://cellsalive.com/mitosis.htm
Results of Cell Division • 2 New Cells with identical information in each other and from the original cell. • Reproduction – unicellular organisms reproduce using cell division (paramecium) • Growth – multicellular organisms use cell division for growth and development • Replacement – replaces cells that wear out or are damaged (skin cells) • Repair – repair damage (broken bones) - nerve cells DO NOT repair or reproduce
Lesson 1 Review pg. 94 #’s 1 - 10
Unicellular Organisms • Unicellular Organisms – one celled living organisms • Prokaryotes – cell w/out membrane bound nucleus - smaller than eukaryotic cells - fewer cell structures - bacteria • Eukaryotes – cell with nuclear membrane & organelles - amoeba, algae, & fungus
Multicellular Organisms • Multicellular Organisms – made of many eukaryotic cells working together. • Cell Differentiation – the process where cells become different types of cells. • Fig. 11 pg. 99 • Stem Cells- unspecialized cells that are able to develop into many different cell types. • Animals • Many found in embryos • Few in adults • Bone marrow – more than a dozen different blood cells • Plants • Meristems – tips of roots and stems • Different plant cells (transport, food, protection)
Tissues • Tissues – groups of similar types of cells that work together to carry out specific tasks. • Animals • Four Main Types • Muscle - movement • Connective – structure, support, connection • Nervous – carries messages to and from the brain • Epithelial - lines the skin, organs, and internal cavities • Plants • Three Main Types • Dermal – protection and prevents water loss • Vascular – transports water and nutrients • Ground - storage, support, photosynthesis
Organs • Organs – groups of different tissues working together to perform a particular job. • Animals • Stomach – muscle – contract to break up food - epithelial – lines the stomach - nervous – signals a full stomach - connective – support • Plants • Leaves – dermal – covers surface - ground – produces food - vascular – moves food and water
Organ Systems • Organ Systems – groups of different organs that work together to complete a series of tasks. • Animals • Digestive System – stomach - small intestine - liver - large intestine • Plants • Two Major Organ Systems • Shoot System – transports food and water • Root System – anchors, takes in water and nutrients
Organisms • Organisms • Multicellular – contain many organ systems, organs, tissues, and cells that all function together and enable the organism’s survival.
Lesson 2 Review pg. 104 #’s 1 - 8