What do Fungi and Animals have in Common?

Similarities between Fungi and Animals

Definition: Fungi are microscopic or macroscopic, non-chlorophyllated, spore bearing, filamentous, heterotrophic thallophytes which reproduce asexually and sexually

Animals are eukaryotic living organism that feeds on organic matter, typically having specialized sense organs and nervous system and able to respond rapidly to stimuli.

Molecular phylogenetic studies revealed that fungi are more closely related to animals than plants

1. Both fungi and animals are without chlorophyll

2. Both are having heterotrophic mode of nutrition (not self synthesizers like plants)

3. In both, the cells are eukaryotic with organelles like mitochondrion, ER, Golgi etc

4. Both store carbohydrate as glycogen (reserve food)

5. Both are having chitin; cell wall of fungus is primarily made up of chitin whereas in some animals, chitin is present in   the exoskeletal structures of insects, spiders and crustaceans.

6. Generally both are multicellular (Exception: Yeast is unicellular fungus)

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7 Major Steps of Scientific Method in Biology with explanation

7 Major Steps of  Scientific Method in Biology

Definition of Scientific Method

Scientific method is an organized and systematized effort to gain knowledge that uses observation and experimentation to describe and explain nature or natural phenomenon. It includes collection of data through observation and experimentation and formulation and testing of hypothesis.

Steps involved in a scientific method or research

Watch a simple 5 minute video here

Step I: Define the problem through observation and by asking questions.

Make an observation. Based on the observation, ask questions. Why, how, what?.  Preliminary answers to these questions will help you to define the problem.  The observation should be correct and repeatable. Observation can be direct using senses or indirect with the help of instruments.

Step II: Research the problem or Review of literature

Research the problem:  This step is often called as review of literature. It is the process of collecting all available information on the selected topic from available authentic sources. It includes research journals, books, periodicals etc. Review of literature will give the researcher a clear picture about the selected topic, helps in making good hypothesis and also helps in avoiding repetition of the work.

Step III: Formulate a Hypothesis

Based on review of literature, the researcher will formulate a hypothesis. Hypothesis is an educated guess, a possible answer or a predictive statement that can be tested by scientific methods or scientifically testable or measurable. This statement is based on our previous experience on the topic or based on existing knowledge (review of literature).

Hypothesis are of two types a)Null Hypothesis and b) Alternative hypothesis

Null Hypothesis

·         The null hypothesis is a hypothesis which the researcher tries to disprove, or nullify.

·         It is denoted by H₀  

·         Accepting the null hypothesis suggest that researchers hypothesis needs revision

Alternative Hypothesis

·         The alternative hypothesis is a hypothesis which the researcher tries to prove.

·         It is denoted by H₁ 

·         Accepting the alternate hypothesis proves that the researchers reasoning is true.

Step IV: Test Hypothesis by conducting experiments.

Here we have to design the experiment and execute the project. We often call the methodology adopted for conducting the experiment as procedure. It should be properly designed to get unbiased results. We need to determine the variables in the experiment

A variable is any factor, trait, or condition that can have different values, change in variable influences the outcome of experimental research

The variable is the factor you might measure in an experiment

Three types of variables:

1. Independent variable: The variable that researcher changes or the researcher think it will affect the dependent variable

        2. Dependent variable: The variable that is affected by change  in independent variable

      3. Controlled variable: The variable that is kept constant or same throughout the experiment.

If possible, the experiment should have a control group.

See here how is controlled variable different from control group

Scientific Method Poster

Step V: Collect and record data. Data collection may be direct (using our senses) or indirect (using scientific instruments). 

Step VI: Analyze and interpret data and draw conclusions.

Analyze data using mathematical tools or statistical software like SPSS for finding out the significance of the result. At the end of the experiment, null hypothesis may be accepted or rejected. Accepting the null hypothesis suggest that researchers hypothesis needs revision

Step VII: Report results or Publish the result. This includes preparation of report, scientific paper or presentation of results or publish it in scientific journals so that your finding is open to public. A theory is a hypothesis supported by large body of observation and experimental evidences. All scientific theories are subjected to revisions or modifications.

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7 Steps of Scientific Method with Explanation Poster

 7 Steps of scientific method in biology poster. 

Scientific method is an organized and systematized effort to gain knowledge that uses observation and experimentation to describe and explain nature or natural phenomenon. It includes collection of data through observation and experimentation and formulation and testing of hypothesis.
7 steps of scientific method in Biology with explanation

Quiz on scientific method

Independent vs Dependent variable

Null vs Alternate hypothesis

Watch this simple 5 min video

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5 Cell wall Synthesis Inhibitors and their Mode of Action

5 Cell wall Synthesis Inhibitor Drugs and its Mode of action

Cell wall is a rigid layer of polysaccharides present outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants it consists mainly of cellulose.

• In fungus, cell wall is primarily made up of chitin
• In Bacteria, cell wall is primarily made up of peptidoglycan except in archaebacteria
• Cell wall offers protection to the cell and maintains its structure and shape
• Many drugs target cell wall as cell wall is essential for the survival of infectious pathogens

Cell wall synthesis inhibitors

1. Penicillin: 

• β lactam antibiotics (beta-lactam ring in their structure)
• effective against gram positive bacteria
• Inhibits bacterial cell wall formation by blocking cross linking of the cell wall structure.
• Inhibits transpeptidase enzyme
• Bacteria formed in the presence of beta-lactams lack cell-wall.

Mode of action: Beta-Lactam Antibiotics bind to specific receptors on bacterial cell membrane called Penicillin Binding Proteins (PBPs) thus inhibiting transpeptidase enzyme that catalyzes cross- linking of peptidoglycan chains of the bacterial cell wall. The target bacterium undergo lysis or cell breakage without cell wall.

2. Cephalosporin: 

• β lactam antibiotics but broad spectrum antibiotic
• Broad spectrum antibiotic generally effective against both Gram positive and Gram negative bacteria.
• having 7- aminocephalosporanic acid nucleus

Mode of action: Similar to penicillin

3. Vancomycin

• Vancomycin is a unique glycopeptide structurally unrelated to any currently available antibiotic.
• Narrow spectrum antibiotic which inhibits the second phase of cell wall synthesis
• Effective against Gram positive bacteria

Mode of action

Vancomycin recognizes and binds to the two D-ala residues on the end of the peptide chains. Thus prevent cross linking of cell wall strands by preventing the binding of cross linking enzyme

There is also evidence that vancomycin alters the permeability of the cell membrane and selectively inhibits ribonucleic acid synthesis.

4. Bacitracin

• polypeptide antibiotic derived from B. subtilis
• primarily effective against gram positive bacteria
• Inhibits peptidoglycan strand synthesis

Mode of action

Peptidoglycan monomers - consisting of the sugars NAM and NAG with a pentapeptide coming off the NAM - are synthesized in the cytosol of the bacterium. These monomers are then transported across the cytoplasmic membrane and inserted into the growing peptidoglycan chain by membrane transporters called bactoprenols.

Bacitracin binds to bactoprenol after it inserts the peptidoglycan monomer transported into the growing cell wall. It subsequently prevents the dephosphorylation of the bactoprenol. Bactoprenol molecules that have not lost the second phosphate group cannot assemble new monomers and transport them across the cytoplasmic membrane. As a result, no new monomers are inserted into the growing cell wall.

Without the active dephosphorylated bactoprenol, peptidoglycan synthesis cannot be completed and the cell lyses occurs*

5. Fosfomycin

• Phosphonic acid derivative produced by Streptomyces sps
• Broad spectrum antibiotic effective against both Gram positive and Gram negative bacteria.
• Acts as phosphoenolpyruvate (PEP) analogue inhibiting the enzyme MurA involved in the first committed step of peptidoglycan cell wall biosynthesis

Mode of action:

Fosfomycin is a phosphoenolpyruvate (PEP) analog that irreversibly inhibits of MurA (UDP-N-acetylglucosamine-3-enolpyruvyl transferase), the cytosolic enzyme responsible for the first step in the peptidoglycan biosynthesis pathway that produces UDP-N-acetylmuramic acid. 

MurA is responsible for catalyzing the transfer of  enolpyruvate moiety of phosphoenolpyruvate (PEP) to the 3′-hydroxyl group of UDP-N-acetylglucosamine in the pathway that produces UDP-N-acetylmuramic acid 

References

Castañeda-García, A., Blázquez, J., & Rodríguez-Rojas, A. (2013). Molecular mechanisms and clinical impact of acquired and intrinsic fosfomycin resistance. Antibiotics, 2(2), 217-236.

Zhanel, G. G., Walkty, A. J., & Karlowsky, J. A. (2016). Fosfomycin: a first-line oral therapy for acute uncomplicated cystitis. Canadian Journal of Infectious Diseases and Medical Microbiology, 2016.

http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit2/control/bacresillus.html

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Causes and Effects of Ozone depletion - Ozone Hole

• Ozone is present mainly in the stratosphere extending 16 kms -50 kms.
• Also known as ozone umbrella, or protective layer.
• The presence of ozone layer in the stratosphere is of vital importance for all living organisms, because the harmful solar radiation, such as ultraviolet rays(UV-B), which are lethal to life on the earth are absorbed by it.
• The ozone umbrella does not allow these harmful UV rays to enter the earth’s atmosphere.

Ozone hole

• The thickness of ozone layer is measured in Dobson unit (DU),where 

                                 1 DU =0.01mm

• The average thickness of the stratosphere ozone layer is estimated to be 32 Du
• A fall in thickness or concentration of spring time ozone layer is termed as ozone hole.
• It was discovered by Farman et al 1985, who coined  the term ozone hole.

Causes of Ozone depletion

• The main cause of ozone layer depletion is the build-up of CFCs (chlorofluorocarbons) in the atmosphere.

• When the CFCs reach the upper atmosphere, high UV radiation reacts with CFCs and releases chlorine atoms. These free chlorine atoms react with ozone thereby leading to the depletion of the ozone layer.

CFCl₃-> CFCl₂+Cl

CFCI₂ ->CFCI+CI

CI+O₃->CIO+O₂

CIO+O₃->CI+2O₂

•  An individual chlorine atom can on average destroy nearly a thousand ozone molecules before it is converted into a form harmless to ozone this is why CFCs are extremely damaging to the ozone layer.
•  The build-up of CFCs is caused by many applications like the production of refrigerants, anesthetics, aerosol sprays.

Social issues and the environment :Climate change, Global warming and Acid rain, Green house effect, ozone layer depletion from Biology Exams 4 U

Ozone Depleting Substances (ODS)

• The green house gases like CFC, Methane and nitrous oxide in the stratosphere destruct ozone layer.
• Substances that cause the depletion of the ozone layer are called Ozone Depleting Substances (ODS).

The different ODS are

• CFCs (14% of total depletion)
• Nitrogen oxides(3.5% depletion)
• Halons (Used in fire extinguishers)
• Methyl Chloroform
• Carbon Tetrachloride
• Hydrofluorocarbons (HCFCs)

Effects of Ozone Depletion

• Due to depletion of ozone layer the dangerous UV B radiation passes through this layer and reaches the earth.
• Cornea absorbs UV b radiations and becomes inflamed. The disorder is called ‘snow blindness’ cataract
• The incidence of UV B radiation damage skin cells cause ageing of skin and skin cancer.
• Decreased photosynthetic activity will increase CO2 concentration of the atmosphere resulting in global warming.

September 16: International  Ozone Day

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Green House Gases, Global Warming and its Effects

Industrial and domestic coal burning release high amount of carbon dioxide,carbon monoxide, chloroflurocarbons, methane, nitrous oxide etc from various sources.They are acting as greenhouse gases.

Green House Gases

The various green house gases are 

• Carbon Dioxide, CO2(warming effect 60%),
• Methane, CH4 (effect 20%)
• Chloroflurocarbons or CFCs(14%),
• Nitrous Oxide, N2O  (6%)
• Others of minor significance are water vapours and ozone.

Social issues and the environment :Climate change, Global warming and Acid rain, Green house effect, ozone layer depletion from Biology Exams 4 U

Global warming

• The excessive increase in the amount of green house gases in the atmosphere raises the temperature by retaining more infrared radiations.
• This excessive green house effect is referred to as global warming.
• CO2 is the most important green house gas that plays   a major role in increasing global warming.
• 60% of the global warming is caused by carbon dioxide. Chloroflourocarbon (CFC), nitrous oxide and methane constitute the remaining 40%of the global warming.

Effects of global warming

• Drought is one of the most serious problems arising from major climate change resulting from global warming. 
• Decrease in precipitation.
• Increased evaporation reduces water available for agricultural , and other uses. It may affect the food production.
• Sea level rise: the melting of glaciers
• Rising of sea level produces negative impacts on human existence, freshwater resources, agricultural and dry lands, animals and bird existence etc.
• Effect on range of species distribution.

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Acid rain: Definition, Causes and Effects - Acid Rain Formula

•The term acid rain was first used by Robert Angus Smith (1872).
•It is described as ‘man’s chemical warfare on nature”.

•Also known as Acid precipitation

What is Acid Rain:

•Acid rain refers to the presence of excessive acid content in the atmosphere and also in the precipitation water(rain, snow, mist, fog etc).

•It is the rain fall and other forms of precipitation with a pH of less than 5 of normal rain is 5.6-6.5.

•Two forms: Wet and Dry

•Wet deposition: Rain, snow and fog

•Dry deposition: it is settle down of wind blown acidic gases and particles over trees, various articles and soil. about 50 of acidity is passed to earth as dry deposition.

Causes of Acid Rain: 

      1. Sulphuric acid and nitric acid are the major agents of acid rain.

a) Formation of Sulphuric acid:

2SO₂+O₂->2SO₃

SO₃+H₂O->H₂SO₄   (Sulphuric acid)

b) Formation of nitric acid

2NO+3[O]->N₂O₅

N₂O₅+H₂O->2HNO₃ (Nitric acid
2. Hydrochloric acid, nitrous acid and carbonic acid also contribute to acid rains.

a) Formation of carbonic acid

             CO₂+H₂O-> H₂CO₃ (Carbonic acid)

             b)Formation of nitrous acid

NO+O₃->NO₂+O₂

NO+NO₂->N₂O₃

                           N₂O₃+H₂O-2HNO₂ (Nitrous acid)
Oxides of nitrogen come from combustion of fuels in automobiles as well as in power plants.
Oxides of sulphur are released from smokestacks of coal fired power plants, smelters and other industries (oil furnaces).

Social issues and the environment :Climate change, Global warming and Acid rain, Green house effect, ozone layer depletion from Biology Exams 4 U

Effects of Acid Rain (Acid precipitation):

Acid rain is very harmful to agriculture, plants, and animals. It washes away all nutrients which are required for the growth and survival of plants. Acid rain affects agriculture by the way how it alters the composition of the soil.

Effect on nitrogen cycle: Nitrogen cycle is highly sensitive to the acidification of soil.  Acidity suppresses denitrification, high  pH increases the volatilization of ammonia, Alkalinity affects the survival of nitrogen fixing bacteria.

Effect on fresh water ecosystems: due to acid rain many lakes in Germany and other European countries have a pH of less than 5, an acidity level considered lethal for many species of fish. Acidic water can carry dissolved aluminum to lakes and streams which clogs the gills of fish and deprives them of oxygen.

Effects on soil: It causes leaching of essential minerals of soil

Effects  on terrestrial ecosystems: It causes extensive damage to forest trees and all vegetation.

Effects on buildings, stone structures (stone leprosy) etc: Acid rain corrodes metals, marble, painted surfaces, slate, stone etc. This phenomenon is called Stone leprosy. In Greece and Italy, valuable stone statues have been partially dissolved and Taj Mahal in India is affected by the acid rain.

. Acid rain has the following reaction with the marble (calcium carbonate):

                                 CaCO3 +  H2SO4 -> CaSO4  + H2O + CO2  

Acid rain damages plants  direct effect on foliage and growing point; necrosis, dieback, chlorosis, defoliation. It causes reduced rates of photosynthesis and growth, increased sensitivity to drought and disease.

Effects on human health: Acidification of soil may leads to the aluminum toxicity of drinking water, which may cause kidney failure, bone softening, Alzheimer’s disease  etc.

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Causes and Effect of Climate Change

Climate: the weather conditions prevailing in an area in general or over a long period.

•A number of factors affect and alter the climate.

•It may be natural and anthropogenic(man made)

Image credit

Causes of climate change:

•The quantum of solar energy reaching the earth.

•Increasing concentration of green house gases in the atmosphere.

•Snow, ice and glaciers which reflect solar radiation back to the atmosphere.

•Ocean currents which play a significant role in heating the earth.

• Volcanic eruptions which can directly influence the  temperature and climate of the earth

Effects of climate change:

        1.Increasing heat stress

2.Abnormal changes in the pattern of rainfall which may result in drought.

3.Depletion of freshwater

4.Melting of polar ice caps and mountain glaciers

5.Rise in  sea level, submergence of coastal lands and islands.

6.Loss of natural habitats and biodiversity.

7. The climate changes which result in tsunamies, El Ninos, cyclones and storms have become increasingly higher.

Social issues and the environment :Climate change, Global warming and Acid rain, Green house effect, ozone layer depletion from Biology Exams 4 U

Pollution:

•  Undesirable change in physical, chemical and  biological characteristics of air, water and soil which may cause any harm to man and other living organisms of the environment is known as pollution.

• Various types of pollution occur on earth which includes water, air, soil, noise and radioactive pollution. These pollutants lead to global environmental changes like green house effect, global warming, acid rain, ozone layer depletion etc.

(El-Nino: It is warm water current in the pacific that periodically flows southwards along the coasts of Eduador. It causes a chin of climatic changes and often induces great storms. )

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