BIO 101 001W CHAPTER 4 Study Guide Questions 1 The scanning electron microscope SEM uses an electron beam to scan the surface of a cell or other sample which is usually coated with a thin film of gold The beam excites electrons on the surface and these electrons are then detected by a device that translates their pattern into an image projected onto a video screen The transmission electron microscope TEM aims an electron beam through a very thin section of a specimen just as a light microscope aims a beam of light through a specimen Magnification is the increase in an objects image size compared with its actual size and Resolving power is a measure of clarity of a image The two parts of a cell theory are that all living matter compose of cells and all cells arise from other cells A Light microscope B Scanning electron microscope C Transmission electron microscope In a light microscope a visible light passes through a specimen then through glass lenses and finally is projected into the viewer s eye 2 Fimbriae attachment structures on the surface of some prokaryotes Capsule jellylike outer coating of many prokaryotes Nucleoid region where the cell s DNA is located not enclosed by a membrane Both types of cells have plasma membranes chromosomes containing DNA and ribosomes Prokaryotic cells are smaller do not have a nucleus that houses their DNA or other membrane enclosed organelles and have smaller somewhat different ribosomes 3 Plant cells have a rigid rather thick cell wall and chemically plants cell walls contain the polysaccharide cellulose unlike the animal cells Chloroplasts central vacuole cell wall and plasmodesmata are structures in plant cells not presented in animal cells Chloroplasts and Vacuoles are two organelles found only in animals Lysosomes and Centrosomes are organelles found in both animals and plants 4 The nucleus contains cell s genetic instructions encoded in DNA These master plans control the cell s activities by directing proteins synthesis The nucleolus a prominent structure in the nucleus is the site where a special type of RNA called ribosomal RNA is synthesized according to instructions in the DNA The nucleus envelope has pores that regulate the entry and exit of large molecules and with the cell s network of membranes called the endoplasmic reticulum 5 The Ribosomes are tiny structures that make proteins according to instructions from the genes Free ribosomes are suspended in the cytoplasm and typically involved in making proteins that function within cytoplasm Bound ribosomes are BIO 101 001W attached to the endoplasmic reticulum associated with the nuclear envelope and associated with proteins packed in certain organelles or exported from the cell 6 The endomembrane system includes the nuclear envelope endoplasmic reticulum Golgi apparatus lysosomes vacuoles and the plasma membrane The smooth ER produces enzymes important in the synthesis of lipids oils phospholipids and steroids Some smooth ER helps store calcium ions The number of Golgi stacks correlates with how active the cell is in secreting proteins a multistep process The Golgi apparatus serves as a molecular warehouse and processing station for products manufactured by the ER 7 Mitochondria mitochondrion are organelles that carry out cellular respiration in nearly all eukaryotic cells converting the chemical energy into foods such as sugars to the chemical energy of the molecular called ATP ATP is the main source for cellular work Chloroplasts are the photosynthesizing organelles of all photosynthesizing eukaryotes Inside the inner membrane is a thick fluid called stroma that contains the chloroplast DNA ribosomes and many enzymes and a network of interconnected sacs called thylakoids The sacs are often stacked like poker chips each stack is called a granum Transport vesicles move membrane and the substances they enclosed between components of the endomembrane system 8 a Intermediate filaments b microtubules c microfilaments 9 Tight junctions prevent leakage of fluid across a layer of epithelial cells Anchoring junctions fasten cells together into sheets Gap junctions are channels that allow molecules to flow through protein lined pores between cells 10 The first category is genetic control where the nucleus that houses a cell s genetic instructions and the ribosomes that produce that protein coded for in those instructions The secondary category includes organelles of endomembrane system that involves in the manufacture distribution and breakdown of material The third category includes the two energy processing organelles mitochondria and chloroplasts And the forth category includes structural support movement and intercellular communication includes the cytoskeleton extracellular structures and connections between cells 11 1 14 done in book and separate sheet of paper