Chapter 3 Cell Structure

Looking at Cells Scientist use microscopes to look at cells Light/electron scopes Micrograph- image as seen through scope Magnification 100X Resolution-clarity of microscopic image

Types of Microscopes Compound light microscope has 2 lenses (multiply #’s) –one = eye piece, –one = objective lense Electron Microscopes Uses an electron beam inside a vacuum chamber Stain specimen w/ metal ions Can magnify up to 200,000X

Cell Features Cell size (small cells have a greater surface area/volume ratio) Prokaryotes -lacks a nucleus and other internal compartments Eukaryotes- have nucleus Cell theory –All living things made of cells –Cells are basic units of structure and function –All cells arise from existing cells

Eukaryotic Cells Nucleus houses the cells’ DNA Organelle-structure that carries out a specfic cell activity Cytoskeleton- provides the interior framework of animal cell - anchors organelles to the cytoplasm

Cell Membrane Lipids form barrier b/w inside and outside of cell Cell membrane only allows certain substances to enter/exit (permeable) See diagrams on pages 60-61

Cell Organelles Nucleus- controls most cell functions Ribosomes- make proteins ER - extensive system of internal membranes that move proteins and other substances through cell Rough ER - ER that has ribosomes attached Smooth ER- makes lipids and break down toxic substances ER, Golgi apparatus, and lysosomes work together in the production, packaging and distribution of proteins (Figure 15 page 64)

Cell Organelles Continued Mitochondria- organelle that makes energy from organic compounds (makes ATP) Mitochondria also has DNA and ribosomes Plant cell organelles –Cell wall is composed of proteins and carbohydrates –Chloroplasts use light energy to make carbohydrates –Central vacuole stores water and helps to control cell pressure