Biology MCQ Quiz - Objective Question with Answer for Biology - Download Free PDF

Explanation:

Epidemic:

• It occurs over a wide geographical area.
• The rise and decline in the epidemic prevalence of an infectious disease are a probability phenomenon that is dependent upon the transfer of an effective dose of the infectious agent from an infected individual to a susceptible one.
• Examples are Measles, Polio.

Endemic :

• An endemic is a sudden outbreak in a certain population or region.
• Examples are Malaria, Chickenpox.

Sporadic :

• It occurs only infrequently, irregularly, or occasionally from time to time in a few isolated places.
• There is no spatial pattern.
• Examples are Rabies, Tetanus

Pandemic :

• A pandemic is an epidemic of an infectious disease that affects a large region, or all over the world.

Examples are the Spanish flu, and Covid -19.

So, the correct answer is a) iii, b) i, c) iv, and d) ii.

Important Points

Additional Information

• Epizootic disease is a disease in an animal population.
• It refers to outbreaks of disease which cause serious or public health issues and are of major importance in the International trade of animals and their products.
• Example: Newcastle disease virus (1990) in colonies on the Great Lakes that resulted in the death of around 10,000 birds.

The correct answer is Red.

Important Points

Photosynthesis:

• It is the process by which Green plants transform Light energy into Chemical energy.
• During Photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.
• Oxidation of water takes place forming Oxygen and the Reduction of Carbon Dioxide takes place forming Glucose.
• Photosynthesis maximum in the Red color of Light and Least in the Violet color of Light.
• Photosynthesis range from 400 to 700 nm, It absorbs the Violet, Blue and Red color of Light.

Additional Information 

Factors affecting Photosynthesis:

• Carbon dioxide concentration: It is best in 0.03 to 0.04 % concentration and beyond this level can cause an increase in fixation rates and can become damaging over longer periods.
•  Water: Water stress causes the stomata to close hence reducing the CO2 availability.
• Temperature: The temperature optimum for photosynthesis of different plants also depends on the habitat that they are adapted to.
• Tropical plants have a higher temperature optimum than the plants adapted to temperate climates.
• Light:  There is a linear relationship between the incident light and CO2 fixation rates at low light intensities. At higher light intensities, gradually the rate increases but does not show further increase as other factors become limiting.

The correct answer is Mitochondria.

Key Points

• Mitochondria is is a double-layered cell organelle, in which the outer layer is porous and the inner layer is folded upon itself is known to be cristae.
• The number of mitochondria in a single cell may be up to 50 to 5000.
• The inner lumen of mitochondria contains ribosome phosphate particles and DNA molecules.
• It has the potential to synthesize its own protein and oxidation of carbohydrates and fats are taken place with the help of enzymes in mitochondria.
• This energy is stored in the form of ATP ( Adenosine Triphosphate ) so, these are known as the "Powerhouse of the cell".

​Additional Information

• Lysosomes:
  • These are also called ''Suicidal bags'' because of their phagocytic activity.
  • Lysosome keeps the cell clean by digesting any foreign material as well as worn-out cell organelles.
  • If any cell or cell organelle gets damaged, the lysosome digest the damaged cell or cell organelle by the application of hydrolytic enzymes (hydrolases – lipases, proteases, carbohydrates)
• Plastids:
  • The plastids are the cell organelles found in all plant cells.
  • They bear some specific pigments, thus imparting specific colours to the plants.
  • Three types of plastids are:
  1. Chloroplast- contains Chlorophyll(Green pigment)
  2. Chromoplast- contains Carotenoid(Red, Yellow and orange pigment)
  3. Leucoplast- contains colourless plastid, mainly stores foodstuff in a plant cell.
• Vacuoles:
  • The term “vacuole” means “empty space”.
  • They can store food or other nutrients required by a cell to survive.
  • They also store waste products and prevent the entire cell from contamination.
  • The vacuoles in plant cells are larger than those in animal cells.
  • The plant vacuoles occupy more than 80% of the volume of the cell. The vacuoles may be one or more in number.

Oesophagus is the food tube.

• It is an organ in vertebrates, by which food travels from the pharynx to the stomach, aided by peristaltic contractions.
• This is a fibromuscular tube with an adult length of around 25 centimetres.
• This is one of the upper digestive system elements.
• Nutrition is absorbed through the mouth and passes through the pharynx first, and then into the oesophagus when swallowed.

The correct answer is Liver.

Key Points

• Urea is synthesized from amino acids in the liver.
• The synthesis of urea in the body is called Urea cycle.
• The end product of protein and amino acids metabolism in the body is called urea.
  • Ammonium ions are formed in the breakdown of amino acids. Some are used in the biosynthesis of nitrogen compounds and the excess ones are converted into urea.
  • Three amino acids, Ornithine, citrulline and arginine participate in this process. Arginine is decomposed to form urea and ornithine in the presence of enzyme arginase and water. Ornithine can be re-used in the cycle.

Additional Information

• Excess ammonia is converted into urea. Urea and water get released from the liver cells into the bloodstream and then transported to the kidneys where the blood is filtered and urine is passed out of body.
• Urine is produced by the kidneys. 

Important Points

•  The formula of Urea or nitrogenous waste - (NH₂CONH₂).

The correct answer is Protein synthesis.

Key Points

• Ribosomes are membranous granular structures present in the cytoplasm.
• They were first observed under an electron microscope as dense particles by George Palade in the year 1953.
• Ribosomes are the site for ''protein synthesis'' so they are also called the ''protein factory'' of the cell.
• There are two types of ribosomes

1. Eukaryotic ribosomes - 80s - occurs in the cytoplasm of eukaryotic cell
2. Prokaryotic ribosomes - 70s - occur in the cytoplasm as well as are associated with the cell membrane of prokaryotic cell.

• The subunits of the ribosomes are:
  • 80s ribosomes - are made of 60s and 40s subunits.
  • 70s ribosomes - are made of 50s and 30s subunits.

Important Points

• Composition of the structure of ribosome:
• They are composed of ribonucleic acid (RNA) and proteins

• Photosynthesis: It is the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. In this process, plant the chlorophyll, carbon dioxide, water, sunlight, and release oxygen.
• Synthesis of Fatty acids occurs in the cytoplasm.

The correct answer is Bile juice, Pancreatic juice.

Key Points

• Bile juice, Pancreatic juice secreted by the organs plays an important role in the digestion of fats.
• Bile juice is secreted by the liver.
  • It does not contain any types of enzymes.
  • The bile juice helps to make the food alkaline and break down the fat molecules.
• Pancreatic juice is secreted by the pancreas.
  • It contains enzymes like amylase, trypsin, pancreatic lipase, nucleases and lipase.
  • Secretion of the Pancreatic juice is regulated by the hormones secretin and cholecystokinin.
• Lipase is the digestive enzyme of fat.
• Ptyalin is the digestive enzyme of the Saliva.
• Hydrochloric acid is produced naturally in the human stomach to help the digestion of food.

The correct answer is Whale.

Key Points

• Gills are respiratory organs found in most aquatic organisms.
• Gills can extract dissolved oxygen from water and excrete carbon dioxide.
• Gills can be found in Octopus, Squid, Clownfish, Tadpole, Prawn, etc.
• Lungs are the breathing organ of Whales.

Additional InformationRespiratory organs of different Animals:

Concept:

Photosynthesis: 

• The leaves have a green pigment called chlorophyll.
• It helps leaves to capture the energy of the sunlight.
• This energy is used to synthesise (prepare) food from carbon dioxide and water. Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis.

In the presence of sunlight Carbon dioxide + water → Carbohydrate + oxygen.

• Some plants, green algae, and cyanobacteria can perform photosynthesis.
• The process of photosynthesis is commonly written as

                   6CO2 + 6H2O + Sun-Light → C6H12O6 + 6O2

Plant cells have a cell wall to protect them and make them rigid structure.

Explanation:

1. Plants convert energy from sunlight into food stored as carbohydrate’s - Correct

2. Plants have chlorophyll. - Correct

3. Plant cells do not have cell walls. - Incorrect.

Additional Information

In the plant cells, there are different components and organelles for specific functions-

• Cell Wall – It is a rigid layer composed of cellulose. It is the outermost layer of the cell, below this cell membrane is present. The primary function of the cell wall is to protect and provide structural support to the cell.
• Cell Membrane – It is a semi-permeable membrane that helps in regulating and the substance for entry and exit inside and outside the cell.
• Nucleus – It is a vital part of the cell as it contains all the information or DNA of the cell and their heredity information for growth and cell division.
• Vacuole – Most of the part of the plant cell is occupied by the vacuole. It is surrounded by Tonoplast. The vital role of the vacuole is to provide support again the pressure of the cell wall.
• Golgi apparatus – They act as a transport system in the cell, as they transport various molecules to a different part of the cell.
• Ribosomes – They are the sites of protein synthesis, also termed as the protein factory of the cell.
• Mitochondrion – They break the complex molecules and produce energy and hence called the powerhouse of the cell.
• Lysosomes – They are termed suicidal bags as they hold the enzymes that are capable to digest the whole cell itself.

An earthworm is a tube-shaped, segmented worm found in the phylum Annelida. They are commonly found living in soil, feeding on live and dead organic matter.

The correct answer is Both chloroplast and mitochondria

Concept:

Theory of endosymbiosis:-

• Symbiotic relationship, where one organism lives inside the other, is known as endosymbiosis. 
• The theory proposed that mitochondria and chloroplasts evolved from engulfed prokaryotes.
• A large anaerobic bacteria engulfed an aerobic prokaryote, which then formed an endosymbiotic relationship with the host, gradually developing into a mitochondrion.
• It is believed that chloroplasts originated from a cyanobacterial endosymbiont.

Explanation:

Similarities between Prokaryotic cells, Mitochondria, and Chloroplast:

• Mitochondria and chloroplast are of the same size as prokaryotic cells.
• Mitochondria and prokaryotic cells both have their own circular DNA.
• The ribosome of bacteria, mitochondria, and chloroplasts have a 70S type of ribosome.
• Divides by binary fission.

• Vitamin K is a vitamin found in leafy green vegetables, broccoli, and Brussels sprouts.
• In the body, vitamin K plays a major role in blood clotting. So it is used to reverse the effects of “blood-thinning” medications when too much is given; to prevent clotting problems in newborns who don’t have enough vitamin K, and to treat bleeding caused by medications.

Tricks:

The correct answer is Cellulose.

• Plant cell walls are primarily made of cellulose.

Key Points

• Cellulose is the most abundant macromolecule on Earth.
  • Cellulose fibers are long, linear polymers of hundreds of glucose molecules.
  • These fibres aggregate into bundles of about 40, which are called microfibrils.

Additional Information

• Carbohydrates are the sugars, starches, and fibres found in fruits, grains, vegetables, and milk products.
  • A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H), and oxygen (O) atoms.
• Lipids are molecules that contain hydrocarbons and make up the building blocks of the structure and function of living cells.
  • A lipid is a biomolecule that is soluble in nonpolar solvents.
• A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid also known as fat molecules in water, as in blood plasma or other extracellular fluids.
  • It consists of a Triglyceride and Cholesterol centre, surrounded by a phospholipid outer shell, with the hydrophilic portions oriented outward towards the surrounding water and lipophilic portions oriented inward toward the lipid centre.

The correct answer is Collenchyma.

 Concept:

• Collenchyma is a specialized simple permanent tissue that provides support and flexibility to plants.
  • This tissue is made up of living cells having uneven thickenings of cellulose, pectin, and hemicellulose on the walls.
  • Cells possess chloroplast, then it is involved in manufacturing sugar and starch.
  • Provides tensile strength and flexibility to the plant body.

Explanation:

• Parenchyma- this tissue provides support to plants. It also stores food. So this option is not correct.

• Collenchyma- it allows easy bending of plant parts and provides flexibility. So the option is correct.
• Sclerenchyma- this tissue makes the plant hard and stiff. It is present in the husk of a coconut. So the option is not correct.

Additional Information

• Parenchyma is the most common and abundant tissue in plants which is made up of thin-walled living cells having a distinct nucleus.
  • The main function of parenchyma is to store and assimilate food. Hence, they are referred to as food storage tissues.
  • Serves as a packing tissue to fill the spaces between other tissues and maintain the shape and firmness of the plant.
  • Stores waste products of plants.
• Sclerenchyma is a lignified supportive tissue made up of thick-walled and lignified cells.
  • Provides mechanical strength to the plant.

Influenza disease is caused by a Virus.

Trick: Virus influence many Diseases