ZOO505 Merged PPT Handouts Topics 1-144

Topic no 1 to 74 mid term and 75 to 144 final term syllabus

1.Introduction to the Study of Cell Biology

Because of their small size, cells can only be observed with the aid of a microscope. Spectacles were first made in Europe in the thirteenth century. The first compound (double-lens) light microscopes were constructed by the end of the sixteenth century.

By the mid-1600s, a handful of pioneering scientists had used their handmade microscopes to uncover a world that would never have been revealed to the naked eye Robert Hooke, an English microscopist discovered the cell at age 27, and he was awarded the position of curator of the Royal Society of London. He took a dead piece of cork and observed empty compartments in it under the microscope, and named them cell. Anton van Leeuwenhoek examined a drop of pond water under the microscope and he observed the crawling microscopic entities which he named as “animalcules”. He was also the first to describe various forms of bacteria, which he obtained from water in which pepper had been soaked and from scrapings of his teeth. In 1838, Matthias Schleiden, a German botanist, concluded that, plants were made of cells and that the plant embryo arose from a single cell. In 1839, Theodor Schwann, a German zoologist and colleague of Schleiden’s, published a comprehensive report on the cellular basis of animal life. Schwann concluded that the cells of plants and animals are similar structures and proposed these two views of the cell theory: All organisms are composed of one or more cells. The cell is the structural unit of life. One of Robert Hooke’s more ornate compound (double-lens) microscopes. (Inset) o Hooke’s drawing of a thin slice of cork, showing the honeycomb-like network of “cells.” Single-lens microscope used by Anton van Leeuwenhoek to observe bacteria and other microorganisms. The biconvex lens, which was capable of magnifying an object approximately 270 times and providing a resolution of approximately 1.35 m, was held between two metal plates .

Basic properties of cells

1. Cells Are Highly Complex and Organized
2. Cells Possess a Genetic Program and the Means to Use It
3. Cells Are Capable of Producing More of Themselves
4. Cells Acquire and Utilize Energy
5. Cells Carry Out a Variety of Chemical Reactions
6. Cells Engage in Mechanical Activities
7. Cells Are Able to Respond to Stimuli
8. Cells Are Capable of Self-Regulation

2.Introduction to Molecular Biology

In the broader terms, definition of molecular biology includes all aspects of the study of life from a molecular perspective. More precisely, the term “Molecular Biology” refers to the biology of the molecules related to genes, gene products and heredity. In other words, the term molecular biology is often substituted for a more appropriate term, Molecular Genetics. So molecular biology grew out of the disciplines of genetics and biochemistry. In the present age, world is in the midst of two scientific revolutions. One is information technology and the other is Molecular Biology. Both deal with the handling of large amounts of information. Molecular Biology has revolutionized the biological sciences as well especially in the fields of Health Sciences and Agricultural Sciences.

3.Introduction to Prokaryotic and Eukaryotic Cells

Two fundamentally different classes of cells

On the base of their size and the types of internal structures, or organelles, cells are divided into two classes.

1. The structurally simpler, prokaryotic cells include bacteria
2. The structurally more complex eukaryotic cells include protists, fungi, plants, and animals.

A Comparison of Prokaryotic and Eukaryotic Cells

Features held in common by the two types of cells:

1. Plasma membrane of similar construction
2. Genetic information encoded in DNA using identical genetic code
3. Similar mechanisms for transcription and translation of genetic information, including similar ribosomes
4. Shared metabolic pathways (e.g., glycolysis and TCA cycle)
5. Similar apparatus for conservation of chemical energy as ATP (located in the plasma membrane of prokaryotes and the mitochondrial membrane of eukaryotes)
6. Similar mechanism of photosynthesis (between cyanobacteria and green plants)
7. Similar mechanism for synthesizing and inserting membrane Proteins
8. Proteasomes (protein digesting structures) of similar construction (between archaebacteria and eukaryotes)

A Comparison of Prokaryotic and Eukaryotic Cells · Features of eukaryotic cells not found in · prokaryotes:

1. Division of cells into nucleus and cytoplasm, separated by a nuclear envelope containing complex pore structures
2. Complex chromosomes composed of DNA and associated proteins that are capable of compacting into mitotic structures
3. Complex membranous cytoplasmic organelles (includes endoplasmic reticulum, Golgi complex, lysosomes, endosomes, peroxisomes, and glyoxisomes)
4. Specialized cytoplasmic organelles for aerobic respiration (mitochondria) and photosynthesis (chloroplasts)
5. Complex cytoskeletal system (including microfilaments, intermediate filaments, and microtubules) and associated motor proteins
6. Complex flagella and cilia
7. Ability to ingest fluid and particulate material by enclosure within plasma membrane vesicles (endocytosis and phagocytosis)
8. Cellulose-containing cell walls (in plants)
9. Cell division using a microtubule-containing mitotic spindle that separates chromosomes
10. Presence of two copies of genes per cell (diploidy), one from each parent
11. Presence of three different RNA synthesizing enzymes (RNA polymerases)
12. Sexual reproduction requiring meiosis and fertilization

Topic 4 Composition of Matter

Topic 5 Molecules of Life

Polymers & Monomers Macromolecules are polymers of smaller monomers molecules Condensation reactions: Monomers join H2O Removal Hydrolysis reactions: Use water to break polymers into monomers.

Topic-06 Unit of Life

Cell Structure Cellular compartments Organelles Structure & Function Life Collection of macromolecules that can perform unique functions because the are enclosed in structural compartment that provides consistency (homeostasis)

Topic-08 Size Matters

Cell Structure Cells are small to maintain large surface area to volume ratio No membrane enclosed internal compartments. Plasma membrane regulates traffic (barrier). Nucleoid region contains DNA. Most have cell wall. Special Features Cyanobacteria Chlorophyll containing have folds of plasma membrane, other have mesosomes (energy). Some have actin like filaments and other have Flagella made-up of Flagellin.

9.Plasma Membrane

Introduction

• The cells are separated from the external world by a thin, fragile structure called the plasma membrane.
• It consists of a lipid bilayer with embedded proteins.
• It is only 5 to 10 nm wide.
• The basic function of the cell membrane is to protect the cell from its surroundings.