chapter 1 lecture notes

chapter 1 lecture notes - Cell and Molecular Biology...

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Cell and Molecular Biology Introduction to Cells This course will cover the basics of Cell and Molecular Biology. This means we will focus on cells as the basic unit of life and the components of cells. All living things are composed of cells . Cells are the minimal subunits of life. Cells are membrane-bounded units that contain a large number of different chemicals and molecules. Cells are defined as having the ability to reproduce themselves- they create copies of themselves and divide in two. Nothing less than a cell can be thought of as living. Viruses, for example, are cell-like in some ways, but they are unable to reproduce themselves and so are not considered to be living (viruses must infect another organism in order to copy themselves). Definition of a cell : The basic unit from which living organisms are made, consisting of an aqueous solution of organic molecules enclosed by a membrane. All cells arise from existing cells, usually by a process of division into two. Simple single cells- the simplest form of life- a single cell is the entire organism - prokaryotes (also spelled procaryote); bacteria; large number of species, evolutionarily ancient; type of cell that lacks a distinct nucleus; also lacks organelles (some procaryotes form chains or clusters- but usually, prokaryotes are single celled) - protista (eukaryotic) - some fungi (single celled yeast – ex. Saccharomyces cerevisiae ) Complex organisms- communities of cells- organized into different groups with different functions - eukaryotes (also spelled eucaryotes) these cells contain a nucleus - fungi, plantae, animalia This course will focus on eukaryotic cells (those with a nucleus) although occasionally we will mention prokaryotes for comparison. Microscopy The field of cell biology would not be possible were it not for the invention of the microscope. - Robert Hooke (1665) used a primitive microscope to examine cork- and he found it to be composed of discrete units (he called these “cells”) - Antonie van Leeuwenhoek (1674) used a simple magnifying lens to look at pond water and saw the first microorganisms (protozoa)
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Thus, we had the discovery of cells and cell theory- that all living cells are formed by the division of existing cells. This was quite controversial- because it had been thought that organisms could arise spontaneously (spontaneous generation). The cell theory was finally proven by Louis Pateur in the 1860s. A key feature of the cell theory that you should remember is that since cells are derived from preexisting cells, all cells resemble the cells that they were derived from. The
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chapter 1 lecture notes - Cell and Molecular Biology...

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