Biological Classification Flashcards
Monera: Cell type, body organisation, mode of nutrition
cell type: prokaryotic
body organisation: cellular
mode of nutrition: autotrophic (chemosynthetic and photosynthetic) and heterotrophic (saprophytic and parasitic)
Protista: Cell type, body organisation, mode of nutrition
cell type: eukaryotic
body organisation: cellular
mode of nutrition: autotrophic {photosynthetic) and heterotrophic
Fungi: Cell type, body organisation, mode of nutrition
cell type: eukaryotic
body organisation: multicellular
mode of nutrition: heterotrophic (saprophytic or parasitic)
Characteristics of Kingdom Monera
- Prokaryotic
- Unicellular
- Lack membrane bound organelles like endoplasmic reticulum, peroxisomes, mitochondria, etc.
Classify bacteria on the basis of shape
- Bacillus or rod shaped: in groups of two they are called diplobacillus and in chains they are called streptobacillus. E.g. Lactobacillus (*underline)
- Coccus or spherical bacteria: Non-motile, lack flagella, in clusters: staphylococcus, in chains: streptococcus
- Spiral or helical bacteria: Have one or more flagella at each pole, e.g. Spriocheates (underline), Spirillum (underline)
- Comma shaped vibrium: Bears a single flagellum at its tip. E.g. Vibrio cholerae (*underline)
Classification of bacteria on the basis of nutrition: 3 categories
- Phototrophs: Bacteria which are capable of synthesising food by themselves by using radiat energy (light)
- Chemotrophs: Bacteria which obtain energy by oxidising chemical compounds
- Heterotrophs: Bacteria which cannot synthesise their own food and hence require organic compounds
How do photoautotrophic bacteria obtain reducing power?
- They convert radiant energy into chemical energy but cannot ‘split’ water to obtain reducing power
- No oxygen is eveolved, and it is called anoxygenic photosynthesis
- Instead they obtain reducing power from thiosulphate, hydrogen sulphide, hydrogen and even some organic compounds
3 types of photoautotrophic bacteria
Green sulphur bacteria: Chlorobium (underline)
Purple sulphur bacteria: Chromatium (underline)
Non-purple sulphur bacteria: Rhodospirillum (*underline)
4 types of chemosynthetic bacteria
Sulphur bacteria: Thiobacillus (underline)
Hydrogen bacteria: Hydrogenomonas (underline)
Nitrifying bacteria: Nitrosomonas (underline), Nitrobacter (underline)
Iron bactera: Ferrobacillus (*underline)
3 types of heterotrophic bacteria
Parasitic: Escherichia coli (underline), Vibrio cholerae (underline)
Saprophytic: Bacillus mycoides (underline)
Symbiotic: Rhizobium (underline) and leguminous plants
Classify bacteria on the mode of respiration
Strict or obligate aerobes: Oxygen is essential for their life
Strict or obligate anaerobes: Cannot grow in oxygen
Facultative bacteria: Can live in environments with or without oxygen
Cell wall structure of Gram +ve and Gram -ve bacteria
Gram +ve:
Thick, single layer
Gram -ve:
Thin, triple layer
Cell wall composition of Gram +ve and Gram -ve bacteria
Gram +ve:
Peptidoglycan present in high amount, teichoic acid present
Gram -ve:
Peptidoglycan present in low amount, teichoic acid absent
Types of asexual reproduction in bacteria
- Binary fission: A mode of asexual reproduction achieved by splitting of parent cell into two equal parts, each of which grows to parental size and form
- Budding: Buds are given out from the bacterial cell and they eventually separate from it by a constriction, developing into a new bacterial cell
- Endospore formation: Some Gram +ve bacteria form endospores which are thick walled, extremely resistant and long lived, they are formed in a vegetative state
E.g. Bacillus (*underline)
Types of sexual reproduction in bacteria (Names only)
- Conjugation
- Transduction
- Transformation
Conjugation
Exchange of genetic material by direct cell-to-cell contact is known as conjugation
Transduction
It is the process by which there is a gene transfer from one bacterium to another by means of a temperate bacteriophage
Transformation
Process whereby cell-free or ‘naked’ DNA containing a limited amount of genetic information is transferred from one bacterial cell to another
Harmful activities of bacteria
- Pathogenic activities: Many bacteria are pathogenic in plants, animals and human beings.
- Food spoilage: Bacteria like Lactobacillus (underline), Proteus (underline), Micrococcus (underline), Streptococcus (underline) cause spoilage of food.
- Water pollution: Many bacteria multiply in water and make it unpotable. Bacteria causing cholera (Vibrio cholerae (*underline)) are generally transmitted through water
Bacterial diseases of plants + their pathogens
Blight of paddy: Xanthomonas oryzae (underline)
Citrus canker: Xanthomonas citri (underline)
Bacterial diseases of human beings + their pathogens
Cholera: Vibrio cholerae (underline)
Typhoid: Salmonella typhi (underline)
Sewage treatment of bacteria stages
- Primary treatment: Physical removal of particles by filtration and sedimentation
- Secondary treatment:
(a) by aerobic bacteria: Effluent is mixed with aerobic bacteria which grow vigorously and digest organic waste material
(b) by anaerobic bacteria: Sludge is muixed with anaerobic bacteria which digest and decompose biodegradable material present in waste
Bacitracin: source, range of action, mode of action
Source: Bacillus subtilis (*underline)
Range of action: Grame +ve bacteria
Mode of action: Inhibits synthesis of bacterial cell wall
Colistin: source, range of action, mode of action
Source: Bacillus colstinus (*underline)
Range of action: Grame -ve bacteria
Mode of action: Destroys cell membrane
Energy production by bacteria
The most useful microbe in energy production is Thermoanerobacter ethanolicus (*underline)
It respires anaerobically and produces ethanol and methane. SInce methane is produced, it is also called a methanogen
Bacteria that helps in the curdling of milk
Lactobacillus (*underline)
In what respect are viruses living?
- Viruses have genetic material (DNA or RNA)
- They mutate
- They can grow
In what respect are viruses non-living?
- They can be crystallized and stored like an ordinary chemical in a bottle or a test tube indefinitely.
- Outside the host, viruses are chemically inert
- They do not have a cell wall, cell membrane, cytoplasm, or cell organelles
What are some characteristics that are unique to viruses?
- Presence of either DNA or RNA
- Capacity to reproduce from the sole nucleic acid
- They do not carry out cell division
D.J. Iwanowsky
Infectious agent of Tobacco mosaic virus can pass through bacterial filter
M.W. Beijerinck
Concept of Contagium vivum fluidum proposed- the extract of infected plants of tobacco could cause infection in healthy plants and called the fluid contagium vivum fluidum
W. M. Stanley
- Virus isolated in crystalline form for the first time
- Electron microscopic study of a plant virus
Viroids
Small single stranded circular RNA agents which infect plants
Prions
Infectious proteinaceous particles without any association with nucleic acids
Kingdom Protista- characteristics
- Eukaryotic
- Unicellular
- Predominantly water dwelling
- Membrane bound structures present
Locomotory organelles in protists
- Pseudopodia: Temporary structures formed by streaming flow of the cytoplasm E.g. Amoeba (*underline)
- Flagella: E.g. Euglena (*underline)
- Cilia: E.g. Paramecium (*underline)
Photosynthetic protists
- Chrysophytes
- algae
- reserve food material as fats, oils, and a polysaccharide called laminarin
Chrysophytes
—> golden brown algae
—> Yellow/green algae
- Dinoflagellates
- cellulosic wall is divided into plates giving them an armoured appearance
- their overgrowth causes red tides
E.g. Gonyaulax (*underline) - Euglenoids
- Have a protein rich layer called pellicle which makes their body flexible
E.g. Euglena (*underline)
Protozoan protists
1) Flagellated protozoans (Zooflagellates):
-Trypanosomes (underline): African sleeping sickness
-Leishmania (underline): kala azar (liver infection)
-Trichonymph (*underline): seen in gut of termites, digest cellulose
2) Amoeboid protozoans (Rhizopods):
-Entamoeba histolyca (*underline): causes amoebic dysentery
Lichen
Symbiotic association of fungi and algae
- Fungi help algae cling to the substrate
- Algae provide food
Mycorrhiza
Symbiotic association of fungi and roots of higher plants
Mode of nutrition of fungi
Heterotrophic
Fungal classification: 4 groups
- Zygomycetes
- Ascomycetes
- Basidiomycetes
- Deuteromycetes
Zygomycetes
- Conjugation fungi
- aseptate hyphae
E.g. Rhizopus stolonifer (*underline)
seen beneath the soil, feed on organic matter, good decomposers
Ascomycetes
- sac fungi (because reproductive organ looks like a sac)
- septate hyphae
E.g. Penicillium notatum (underline)
Saccharomyces cerevisiae (underline) (yeast)
Basidiomycetes
Club fungi
E.g. Agaricus bisporus (*underline)
Deuteromycetes
-Imperfect fungi because they do not exhibit a sexual life cycle
E.g. Alternaria (*underline)
Beneficial fungi
- Edible mushrooms
- Yeast used in baking
- Preparation of organic acids like citric acid
- Effective decomposers
Harmful fungi
- Fungal rot, specially in food E.g. Bread mould
- Fungal spores as allergens
- Responsible for causing diseases in plants and animals
