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CELL STRUCTURE AND FUNCTION

CELL STRUCTURE AND FUNCTION. CHAPTER 4. CELL DIVERSITY. The diversity of cell shapes reflects the different functions of cells. Examples: -nerve cells -skin cells . CELL SIZE.

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CELL STRUCTURE AND FUNCTION

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  1. CELL STRUCTURE AND FUNCTION CHAPTER 4

  2. CELL DIVERSITY The diversity of cell shapes reflects the different functions of cells. Examples: -nerve cells -skin cells

  3. CELL SIZE The size of a cell is limited by the relationship of the cell’s outer surface area to its volume or surface area-to- volume ratio.

  4. 4. As a cell grows, it volume increase much faster than its surface area does. 5. Why must cells be so small? -If the cell’s surface area were too big, materials could not pass into or out of cell quickly enough to meet the cell’s needs.

  5. BASIC PARTS OF ALL CELLS All cells have: -an outer boundary (plasma membrane) -

  6. an interior substance (cytoplasm/cytosol)

  7. -a control region (nucleus for eukaryotes, nucleoid for prokaryotes)

  8. TWO TYPES OF CELLS Prokaryotic cells -lack a membrane-bound nucleus -lack membrane-bound organelles -divided into two domains: Bacteria and Archaea

  9. Eukaryotic cells -membrane-bound nucleus -membrane-bound organelles -generally larger than prokaryotic cells

  10. CELLULAR ORGANIZATION A collection of genetically identical cells that live together in a connected group = colonial organism

  11. 10. An example of true multicellularity = cells  tissue  organs  organ system

  12. CELL ORGANELLES Nucleus -controls most functions of the cell -houses and protects cell’s genetic information (DNA in the form of chromatin)

  13. -surrounded by nuclear membrane (nuclear pores and double layer) -nucleolus (dense area that produces ribosomes)

  14. Mitochondria -transfers energy from organic molecules to ATP -more active cells have more mitochondria -double membrane -inner membrane is folded into cristae (provides surface area for reactions)

  15. Mitochondria have their own DNA and can reproduce only by the division of preexisting mitochondria. Ribosomes -made of proteins and RNA (two subunits) -build proteins -free in cytosol or attached to ER

  16. Endoplasmic reticulum (ER) -system of membranes, tubes, and sacks = cisternae -intracellular highway Rough ER -covered with ribosomes -produces phospholipids and proteins that will be exported from cell -attached to nuclear membrane

  17. Smooth ER -builds lipids (cholesterol) -produces steroid hormones (estrogen and testosterone) -releases calcium (muscle contractions) -detoxifies drugs and poisons in kidney and liver cells

  18. Golgi apparatus -system of flatten membranous sacs -receives vesicles from ER containing newly made proteins or lipids -modifies vesicle contents

  19. Lysosomes -vesicles that bud from the Golgi apparatus and that contain digestive enzymes -digest large molecules and worn out cell organelles (autophagy) -plays roll in apoptosis (programmed cell death)

  20. Peroxisomes -not produced by Golgi apparatus -abundant in liver and kidney cells -neutralize free radicals (oxygen ions that can damage cells) -detoxify alcohol and other drugs -break down fatty acids (for energy)

  21. Cytoskeleton -network of thin tubes and filaments that crisscross the cytosol -give shape to the cell -acts as a system of internal tracks

  22. Cilia and flagella -hair like structures that extend from the surface of the cell and assist in movement -cilia are short and numerous around the cell -flagella are longer and less numerous

  23. Cell wall- rigid layer that lies outside of the cell membrane -plant cells: cellulose -fungi: chitin

  24. Central vacuole- large fluid-filled organelle that stores water, enzymes, metabolic wastes and other materials -may also contain toxins or pigments

  25. chloroplast- site of photosynthesis -contains DNA

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