KINGDOM PROTISTA

Introduction

The word protista came from Greek meaning the very first; they are eukaryotic in nature. Eukaryotes are a group of organisms with nucleus under the domain: eukarya while the kingdom consists of both multicellular and unicellular organisms, these organisms were not plants, animals or fungi and as a result do not fit into any other kingdom. Therefore, the term protista has been adopted to refer to organisms that appear similar but are not from the same group (taxon). The word Protista has now been abandoned and focus has been shifted to the various lineage that exists within it.

General Characteristics of Kingdom Protista 

1. Many are unicellular while some are multicellular.

2. They are eukaryotes.

3. Some are motile while some are non-motile.

4. They move either by flagella, cilia or may be ameboid in nature.

5. Some are heterotrophic in nature (including the parasitic forms); while some are photosynthetic, others may be both photosynthetic and heterotrophic (mixotrophic).

6. They are mostly aquatic, some are found in moist soil while others live in the body of plant and animals.

7. Their mode of reproduction can be either by asexual or sexual means: binary fission and conjugation.

Phyla

There are controversies among scientists concerning some classification of certain organisms into phylum as the name protista is not monophyletic i.e organisms having the same ancestral origin. For instance, the older phylum protozoa consists of animal-like organisms that may not be from the same ancestral origin (clade); also classification of some algae into kingdom plantae or protista is also controversial. However, there are about 16 phyla in the kingdom protista grouped into five informal groups based on mobility and nutrition namely;

1. Heterotrophs (no locomotor apparatus): This group include Rhizopoda, Actinopoda and Foraminifera.

2. Photosynthetic (protists): This include pyrrophyta, euglenophyta, chrysophyta, Xanthophyta, Bacillariophyta, Rhodophyta, Phaecophyta and chlorophyta.

3. Heterotrophs (with flagella): Sarcomastigophora, Ciliophora.

4. Non-Motile (spore formers): Apicomplexa

5. Heterotrophs (with restricted mobility): Oomycota, Acrasiomycota and Myxomycota.

Rhizopoda e.g Amoebas (move by pseudopodia). They were formerly classified as protozoa.

Actinopoda e.g Radiolarians having glassy-like skeletons with needle-like pseudopodia.

Foraminifera e.g Forams having shells and moving by protoplasmic streaming.

Pyrrophyta e.g Dinoflagellates which are regarded as Red tides are photosynthetic (having chlorophyll a and b), and possessing two unequal flagella.

Euglenophyta e.g Euglena which possess flagella, possess chloroplast containing chlorophyll a and b; they are photosynthetic.

Chrysophyta Include e.g Golden Algae (chrysophyceae); also include diatoms (bacillariophyceae) and yellow-green algae (Xanthophyceae)

Rhodophyta e.g Red Algae which are mostly multicellular, containing red pigment and chlorophyll a.

Phaecophyta e.g Brown Algae such as Kelps are multicellular, contain chlorophyll a and c.

Chlorophyta include Green Algae such as Chlamydomonas are also multicellular; contain chlorophyll a and b.

Sarcomastigophora e.g Trypanosome (Zoomastigotes) are multicellular animal-like organisms containing flagellum and are parasitic; transmitted by vectors Tsetsefly (Glossina palpalis and Glossina moritans). They were formerly classified as phylum protozoa.

Ciliophora e.g Paramecium are multicellular animal-like organisms having cilia and are free living. They were formerly classified as protozoa.

Apicomplexa e.g Plasmodium (formerly classified as protozoa) are multicellular animali-like organisms that are non motile, spore formers (sporozoans) and parasitic.

Oomycota e.g Water molds, rusts and mildews which are both terestial and freshwater organisms.

Acrasiomycota e.g cellular slime molds such as Dictyostelium which are in colony of cells and are similar to amoebas.

Myxomycota e.g plasmodial slime molds such as Fuligo which stream along with multinucleated mass of cytoplasm.

It is important to note that the Kingdom Protista and some phyla such as Protozoa have been abandoned. Scientists have come up with the new classification system that do not include kingdoms rather, consist of supergroups.

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Nanotechnology: Introduction

Introduction

Nanotechnology can be described as a science, engineering and technology that is conducted at a nano scale. It involves manipulation of individual matter at the level of atoms (atomic level), molecular and or supramolecular level. It deals with materials having at least one spatial dimension in the size range of 1 to 100 nm.  What comes to your mind whenever you hear the word nano is 10-9 and one nanometer is one billionth of a meter. In order to work at the atomic level one needs a suitable microscope such a scanning tunneling microscope (STM) and atomic force microscope (AFM). Nanotechnology is an interdisciplinary and also referred to as general purpose technology.

History

The term nano came from the Greek word nanos meaning 'dwarf’; consequently, very small objects come to the mind when we hear the word nanotechnology. Although human exposure to nanoparticles has occurred throughout human history which dramatically increased during the industrial revolution. The study of nanoparticles is not new as the concept of ‘‘nanometer’’ was first proposed by Richard Zsigmondy in 1925; a Nobel Prize Laureate in chemistry who coined the term expressly for characterizing particle size and he was the first to measure the size of particles such as gold colloids using a nanometer.  However, Richard Feynman, the 1965 Nobel Prize Laureate in physics is often credited for introducing the concept of nanotechnology and therefore called the father of nanotechnology. He presented a lecture titled "There's Plenty of Room at the Bottom" where he introduced the concept of manipulation at the atomic level. The new idea he presented demonstrated new ways of thinking and his hypotheses were proven correct.

Fifteen years later, a Japanese scientist named Norio Taniguchi was the first to use the word nanotechnology to describe semiconductor processes that occurred on the order of nanometer and advocated that nanotechnology consisted of the processing, separation, consolidation, and deformation of materials by one atom or one molecule. Thereafter, the golden era of nanotechnology began in the 1980s when Eric Drexler of Massachusetts Institute of Technology (MIT) used ideas from Feynman’s book and Taniguchi’s term nanotechnology in his book titled, ‘‘Engines of Creation: The Coming Era of Nanotechnology’’ in 1986; he proposed the idea of a nanoscale ‘‘assembler’’ which would be able to build a copy of itself and of other items of arbitrary complexity. His vision of nanotechnology is often called ‘‘molecular nanotechnology.’’

Nanotechnology's advancement became popular when Iijima and another Japanese scientist, developed carbon nanotubes; the beginning of the 21st century saw an increased interest in the emerging fields of nanoscience and nanotechnology. In the United States, Feynman’s stature and his concept of manipulation of matter at the atomic level played an important role in shaping national science priorities. President Bill Clinton advocated for funding of research in this emerging technology during a speech at Caltech on January 21, 2000. Three years later, President George W. Bush signed into law the 21st Century Nanotechnology Research and Development Act. The legislation made nanotechnology research a national priority and created the National Technology Initiative (NNI). Today, the NNI is managed within a framework at the top of which is the President’s Cabinet-level National Science and Technology Council (NSTC) and its Committee on Technology. The Committee’s Subcommittee on Nanoscale Science, Engineering, and Technology (NSET) is responsible for planning, budgeting, implementation, and review of the NNI and is comprised of representatives from 20 US departments and independent agencies and commissions.

Approaches in Nanotechnology: Synthesis of Nanomaterials

There are two approaches to the synthesis of nanomaterials: bottom-up and top-down. The bottom-up approach involves molecular components arranging themselves into more complex assemblies atom-by-atom, molecule-by-molecule, cluster-by-cluster from the bottom as in the growth of a crystal. These approaches, arrange molecular components themselves into some useful conformation using the concept of molecular self-assembly; synthesis of nanoparticles by colloid dispersions is an example of the bottom-up approach. 

In the top-down approach,  it has to do with creating nanoscale devices by using larger, externally-controlled devices to direct their assembly; this approach often uses the traditional workshop or microfabrication methods in which externally-controlled tools are used to cut, mill and shape materials into the desired shape and order. Attrition and milling for making nanoparticles are typical top-down processes. 

Structure of nanomaterials 

The structure of the nanomaterials can be classified by their dimensions. The zero-dimensional nanostructures are nanoparticles. The one-dimensional nanostructures are whiskers, fibers (or fibrils), nanowires and nanorods. In many cases, nanocables and nanotubes are also considered one-dimensional structures. Thin films are considered as two-dimensional nanostructures. Colloids bearing complex shapes have three-dimensional nanostructures. 

Applications of Nanotechnology

Nanotechnology has been applied in many sectors around the world; current applications of nanoscale products in consumer products around the world include:

1. Automotive: production of air and oil filters, waxes, engine oil, anti-scratch finishes, car wax, air purifiers, catalysts to improve fuel consumption, tires.

2. Clothing and Textiles: wrinkle and stain resistant apparel, antibacterial and anti-odour clothing, antibacterial fabrics, UV resistant and protective clothing, flame retardant fabrics.

3. Cosmetics: skin cream and moisturizers, skin cleansers, sunscreen, make up removal.

4. Electronics: batteries, electronic displays; organic light emitting diodes (OLED and LEDs), data memory, antibacterial and anti-static coatings on keyboards, mouse, cell phones, DVD coatings, mp3 players, computer processors and chips.

5. Food, Food Additives and Food Packaging: energy drinks, nutritional supplements, food storage containers, antibacterial utensils, cutting board, plastic wrap, food packaging, nano tea, chocolate shakes, canola active oils.

6. Household: antibacterial furniture and mattresses, antibacterial coatings in appliances, filters, air purifiers, self-cleaning glass, antibacterial, UV resistant paints, vacuums, solar cells, cleaning products, disinfectant sprays, fabric softeners.

7. Health/Personal Care: hearing aids, body wash, contact lenses, cellulite treatment, tooth powder, shampoos, hair gel, deodorants, insect repellents, antibacterial creams, bandages, home pregnancy tests, drug delivery patches, man made skin.

8. Sport Equipment: gulf balls and club, tennis racket and balls, base ball bats, hockey sticks, skis and snowboards, ski wax, bicycle parts, wet suits, shoe insoles, anti-fogging coats.

9. Toys and Children's Goods: stain resistant plush toys, antibacterial baby pacifiers, mugs and bottles, X-boxes and PlayStation, antibacterial stuffed toys.

10. Medical Application: drugs, medical devices

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KINGDOM MONERA AND THEIR CHARACTERISTICS

Kingdom Monera 

The work of Carolus Linnaeus and Woese in 1758-1759 and 1990 respectively has been the foundation and influenced the classification system of living things up to the present times. Before you continue with this topic, you should have watched our video lesson on Classification of Living Things.

Objectives of today's topic are:

1. Identify the two domains involved in this kingdom.

2. List ten characteristics of this kingdom.

3. List two major phyla under Eubacteria (Bacteria domain).

4. State eight characteristics of phylum schizophyta.

5. List three common examples of harmful organisms in this kingdom.

6. List three common examples of beneficial organisms in this kingdom.

7. Enumerate ten characteristics of phylum cyanophyta.

8. List three harmful effect of cyanobacteria bloom in aquatic environment.

9. List three common examples of organisms in cyanophyta.

10. What characteristic features differentiate archaebacteria from eubacteria?

Introduction

This kingdom consists of organisms that are classified under two domains: bacteria and archea. They are referred to as eubacteria and archeabacteria respectively.

Characteristics of Kingdom Monera

1. They are unicellular or single cell organisms.

2. They are prokaryotes, they do not have membrane bound organelles.

3. Their cells do not possess endoplasmic reticulum or mitochondria.

4. They reproduce by asexual means mostly by binary fission. Other modes include spore formation and horizontal gene transfer.

5. Archaebacteria may have both sexual and asexual mode of reproduction ranging binary fission, conjugation etc. 

6. Some possess chlorophyll and are photosynthetic in their mode of nutrition.

7. Some do not possess chlorophyll and so they are heterotrophic in their mode of nutrition.

8. Some may be motile while most are non-motile (ability to move).

9. Those that are motile have motility organelles such as flagella and cillia.

10. Some may possess cell wall (most bacteria species) and some do not have cell wall.  

Note: Eubacteria have two major phyla which are schizophyta and cyanophyta.

           Archaebacteria have their separate division.

Phylum Schizophyta: Characteristics

The name of this phylum is obsolete since the creation of domains but this phylum consists majorly the bacteria (eubacteria). Their specific characteristics are:

1. They are prokaryotes, unicellular organisms.

2. They reproduce by binary fission (an asexual mode of reproduction).

3. They possess cell wall containing polysaccharides and amino acids  called PEPTIDOGLYCAN.

4. They do not contain chlorophyll and are not photosynthetic.

5. They are mostly motile and possess motility organelles like flagella.

6. Some can cause plant and animal diseases. They are pathogenic e.g Vibrio cholerae (cholera), Clostridium dificile (dysentery), Treponema palidum (syphilis), Neiserria gonorrhoeae (gonorrhea) etc.

7. Some are beneficial or economical e.g Lactobacillus acidophilus (yoghurt, lactic acid production), Streptomyces griseus (antibiotics), Bacillus thuringiensis (biological control of pests). 

8. They have different appearances and shapes e.g cocci-round (Streptococcus), bacilli- rod (Bacillus cereus, Escherichia coli), vibrio- curved (Vibrio cholerae), spirochete- spiral (Treponema pallidum).  

Phylum Cyanobacteria: Characteristics

This phylum consists of chlorophyll containing bacteria and this include blue-green bacteria and prochlorophyta group. Their specific characteristics are:

1. They can occur in form of filaments or colonies.

2. They possess chlorophyll and are photosynthetic.

3. Other pigments include carotenes, xanthophylls, c-phycoerythrins and c-phycocyanins.

4. Their cells have cell wall.

5. They do not have flagella or cilia.

6. They are motile by means of gliding.

7. They reproduce by binary fission.

8. Some filamentous cyanobacteria have special structures heterocysts which help them fix nitrogen (converting atmospheric nitrogen into chemical form which is utilized by the organisms).

9. They are found in freshwater, marine and terrestrial environment.

10. They are the major oxygen producing bacteria.

Some produce toxic substance which makes them inedible for most herbivores.

11. They cause bad odour, water contamination, creates anoxic environmental for aquatic animals when they grow on water surfaces (bloom).

12. Examples include Nostoc, Anabena, Oscillatoria etc. 

ARCHAEBACTERIA

The word "achae" is from the Greek word meaning "ancient". Therefore, they are the oldest living organisms on the planet earth. Their major characteristics are: 

characteristics

1. They are unicellular organisms.

2. They are prokaryotes but the genetic examinations (16 sRNA) showed that they are different from bacteria.

3. Many has cell wall but few (Ferroplasma and Thermoplasma)  don't have cell wall.

4. Their cell wall lack peptidoglycan.

5. Some achaebacteria have pseudopeptidoglycan (similar to bacteria peptidoglycan but chemically different).

6. Their membrane contains lipids which are glycogen-ether linked.

7. They have plasmids (circular fragments of DNA).

8. Their DNA is circular.

9. Their mode of nutrition can phototrophic, lithotrophic or organotrophic.

10. They are found in extreme environments and so can be classified according to their habitat I.e halophiles or halophilic (salt loving), acidophiles or acidophilic (acid loving), thermophiles or thermophilic (extreme high temperature loving) and methanogens (methane gas producers).

Archaebacteria phyla

Acheabacteria can be divided into twelve phyla namely: Aigarchaeota, Bathyarchaeota, Crenarchaeot,Euryarchaeota, Geoarchaeota, Heimdallarchaeota, Korarchaeota, Lokiarchaeota, Nanoarchaeota, Odinarchaeota, Thaumarchaeota and Thorarchaeota.

Examples of achea include Acidolobus, Halorubium, Desulfurococcus, Sulfolobus etc.  

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TELL US YOUR VIEW ON HEALTH AND WELLNESS SURVEY

This questionnaire is to seek general opinion about health and wellness. This covers psychology, sexual, social, marital and financial factors that affect peoples health and wellness. 

Please, I want your sincere response as all responses shall be kept confidential and for educational purpose only. Thanks 

Tell Us Your View

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THE CELL

In this video, you should learn the history of the cell, the cell theory, types of cells, plant and animal cell.

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PARTS OF THE MICROSCOPE AND THEIR USES

This video explains the Microscope, thee various parts and their functions.

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MICROSCOPY: HOW TO USE THE MICROSCOPE

This video explains microscopy, what you need to know about handling, preparation of slide and viewing under the microscope and returning the microscope after use.

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