LSU Biol 1201 LiCata Exam 2 Questions and Answers with complete solution

Cell theory - -All organisms are made of cells -The cell is the simplest collection of matter that can be alive -Cells are near the middle of the biological size range scanning electron microscope - Focus electrons onto the surface of a specimen, providing images that look 3-D Transmission Electron Microscopes - focus a beam of electrons through a specimen cell fractionation - Takes cells apart and separates the major organelles from one another centrifuges fractionate cells into their component parts Basic Features of all prokaryotes and Eukaryotes - -Plasma Membrane -Semifluid substance called cytosol -Chromosomes (carry genes) -Ribosomes (make proteins) Prokaryotic cells - -No nucleus -DNA in an unbound region called the nucleoid -No membrane bound organelles Eukaryotic cells - -DNA in nucleus with a membrane -Membrane-bound organelles -Internal Membranes = the endomembrane system -Generally much larger than prokaryotic cells -Plant and Animal cells have most of the same organellesNucleus - -Contains most of the cell's genes -nuclear envelope encloses the nucleus -Nuclear membrane is a lipid bilayer -Nuclear pores regulate the entry and exit of molecules -the shape of the nucleus is maintained by the nuclear lamina, which is composed of protein Chromatin - -DNA associated with proteins in the nucleus -It condenses to chromosomes as a cell prepares to divide -Each chromosome is a single DNA molecule associated with proteins