cells(introduction&discovery)

“CELLS” ~INTRODUCTION & DISCOVERY~: 

“CELLS” ~INTRODUCTION & DISCOVERY~

CONTENTS: 

CONTENTS I. Discovering Cells i. Cell Theory ii. Types of Cells iii. Sizes of the Cells II. Cell & it’s Environment i. Structure of Cell Membrane III. Modern Cell Biology i. Cytology ii. Biochemistry iii. Genetics

Key Words: 

Key Words CYTOLOGY: branch of biology concerned with the structures and functions of cells. Or simply study of cells. BIOCHEMISTRY: study of chemical and physicochemical processes that occur within the living organisms. GENETICS: study of heredity and the variation of inherited characteristics. PROKARYOTES: a group of organisms that lack a cell nucleus. Without true nucleus. EUKARYOTES: organisms with true nucleus.

KEY PERSONS: 

KEY PERSONS - ROBERT HOOKE - ROBERT BROWN - THEODORE SCHAWNN - MATTHIAS SCHLEIDEN - RUDOLF VIRCHOW - FRIEDRICH WOHLER - LOUIS PASTEUR

Slide 5: 

I. DISCOVERING CELLS

i. Cell Theory : 

i. Cell Theory refers to the idea that cells are the basic unit of structure in every living thing. Development of this theory during the mid 17th century was made possible by advances in microscope. This theory is one of the foundations of biology. The theory says that new cells are formed from other existing cells, and that the cell is a fundamental unit of structure, function and organization in all living organisms.

History of CELLS: 

History of CELLS The cell was discovered by ROBERT HOOKE in 1665. He examined (under a coarse, compound microscope) very thin slices of cork and saw a multitude of tiny pores that he remarked looked like the walled compartments a monk would live in. Because of this association, Hooke called them cells, the name they still bear. However, Hooke did not know their real structure or function. Hooke's description of these cells (which were actually non-living cell walls) was published in Micrographic .His cell observations gave no indication of the nucleus and other organelles found in most living cells. The observations of Hooke, Leeuwenhoek, Schleiden , Schwann, Virchow, and others led to the development of the cell theory. The cell theory is a widely accepted explanation of the relationship between cells and living things. The cell theory states: -All living things or organisms are made of cells and their products. -New cells are created by old cells dividing into two. -Cells are the basic building units of life.

ii. Types of Cells: 

ii. Types of Cells Prokaryote: Prokaryotes do not have a nucleus, mitochondria, or any other membrane-bound organelles. In other words, neither their DNA nor any of their other sites of metabolic activity are collected together in a discrete membrane-enclosed area. Instead, everything is openly accessible within the cell, some of which is free-floating. Prokaryotes belong to two taxonomic domains: the bacteria and the archaea .

Eukaryote:: 

Eukaryote: Eukaryote cells include a variety of membrane-bound structures, collectively referred to as the endomembrane system . Simple compartments, called vesicles or vacuoles , can form by budding off other membranes . The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus , or nuclear envelope , within which the genetic material is carried. [

iii. Sizes of the Cells: 

iii. Sizes of the Cells Although it is generally the case that biological cells are too small to be seen at all without a microscope, there are exceptions as well as considerable range in the sizes of various cell types. Eukaryotic cells are typically 10 times the size of prokaryotic cells (these cell types are discussed in the next Chapter). Plant cells are on average some of the largest cells, probably because in many plant cells the inside is mostly a water filled vacuole.

II. Cell & it’s Environment: 

II. Cell & it’s Environment

i. Structure of Cell Membrane: 

i. Structure of Cell Membrane A membrane separates a cell from its environment or subdivides a cell into specialized regions or compartments. The structure of a membrane is best understood in light of its component parts and in the context of the specialized functions performed by the cell or by its various, membrane-bound compartments. Cellular membranes consist mainly of phospholipid assembled into a stable, sheet like structure called a bilayer . The process of assembly occurs spontaneously under normal cellular conditions once phospholipid has been synthesized. To understand this process and the important properties of all membranes, it is necessary to appreciate the amphipathic nature of phospholipid structure. An amphipathic lipid is structurally polarized into a molecular region that is hydrophilic and one that is hydrophobic . When the phospholipids in an aqueous environment like cytoplasm reach a critical concentration, they associate into aggregates that are more stable in an aqueous environment than are the individual lipids. These aggregates, or micelles, can assume several forms, but they all have two features in common: The polar "heads" of the phospholipids project into the aqueous environment, and the hydrophobic regions or "tails" are oriented away from water. At low lipid concentrations the micelles are spherical; at higher concentrations, the micelles aggregate to form an extended, two-dimensional sheet called a bilayer.

III. Modern Cell Biology: 

III. Modern Cell Biology

i. Cytology: 

i. Cytology Cytology means "the study of cells". Cytology is that branch of life science, which deals with the study of cells in terms of structure, function and chemistry. Based on usage it can refer to: Cytophatology : the study of cellular disease and the use of cellular changes for the diagnosis of disease. Cell Biology : the study of (normal) cellular anatomy, function and chemistry.

ii. Biochemistry: 

ii. Biochemistry Biochemistry , sometimes called biological chemistry , is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes. By controlling information flow through biochemical signaling and the flow of chemical energy through metabolism, biochemical processes give rise to the incredible complexity of life. Much of biochemistry deals with the structures and functions of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other bimolecular although increasingly processes rather than individual molecules are the main focus.

iii. Genetics: 

iii. Genetics Genetics deals with the molecular structure and function of genes, with gene behavior in the context of a cell or organism, with patterns of inheritance from parent to offspring, and with gene distribution, variation and change in populations. Given that genes are universal to living organisms, genetics can be applied to the study of all living systems, from viruses and bacteria, through plants and domestic animals, to humans. Father of genetics: GREGOR MENDEL

hope you enjoy about it… thank you for watching… hope you learn…: 

hope you enjoy about it… thank you for watching… hope you learn…

Prepared by: ALLEN JOHN DOMOGMA CAMILLE AJES BSEd 1-S Mr. Dellosa: 

Prepared by: ALLEN JOHN DOMOGMA CAMILLE AJES BSEd 1-S Mr. Dellosa