ASS 1: The structure of cells/tissues and their properties
By Benjamin Bowles
Page 1 Contents Page
Page 2 Introduction
Page 3 Introduction (cont.)
Page 4 Diagrams of animal cell, plant cell and bacteria cell Page 5 Table of Organelles
Page 6 Table of differences between Prokaryotic and Eukaryotic cells Page 7 (a,b,c,d) Cell drawings of onion cells and cheeks cells Page 8 Electron micrograph of an animal cell
Page 9 List of four tissue types with diagrams
Page 10 List of four tissue types with diagrams (cont.)
Page 11 Cell differentiation plus two examples.
Page 12 Gastrulation – Endoderm, Ectoderm, Mesoderm with diagrams Page 13 Gastrulation (cont.)
Page 14 Stem Cells – Embryonic, Adult
Page 15 Stem Cells (cont.)
Page 16 Muscle Tissue
Page 17 Muscle Tissue (cont.)
Page 18 Muscle Tissue (cont.)
Page 19 Epithelium Tissue
Page 20 Epithelium Tissue (cont.)
Page 21 Epithelium Tissue (cont.)
Cells (Prokaryotic and Eukaryotic), Tissues, Cell Theory and the Cell Hierarchy
The cell is the structural and functional unit of all known living organisms. It is the simplest unit of an organism that is classified as living, and is sometimes called the building block of life. Some organisms, such as bacteria are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion cells; a typical cell size is 10 micrometers, a typical cell mass is 1 nanogram.) The largest known cell is an ostrich egg.
The word cell comes from the Latin cellula, meaning a small room. The descriptive name for the smallest living biological structure was chosen by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.
Each cell is at least somewhat self-contained and self-maintaining: it can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce as necessary. Each cell stores its own set of instructions for carrying out each of these activities.
There are two types of cells: eukaryotic and prokaryotic. Prokaryotic cells are usually single cells, while eukaryotic cells are usually found in multicellular organisms.
Prokaryotes are distinguished from eukaryotes on the basis of nuclear organization, specifically their lack of a nuclear membrane. Prokaryotes also lack most of the intracellular organelles and structures that are characteristic of eukaryotic cells (with the exception of ribosomes which are found in both types of cells). Most of the functions carried out by these organelles are taken over by the prokaryotic plasma membrane.
Eukaryotic cells are about 10 times the size of a typical prokaryote and can be as much as 1000 times greater in volume. The major difference between prokaryotes and eukaryotes is that eukaryotic cells contain membrane-bound compartments. Most important among these is the presence of a cell nucleus, which houses the eukaryotic cell’s DNA. It is this nucleus that gives the eukaryote its name, which means “true nucleus”.
Tissue is a cellular organizational level intermediate between cells and a complete organism. Hence, a tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues.
Biological tissue is a collection of interconnected cells that perform a similar function within an organism. The study of tissue is known as histology, or in connection with disease, histopathology. The classical tools for studying the tissues are the wax block, the tissue strain, and the optical microscope, though developments in electron microscopy, immunofluresence, and frozen sections have all added...