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

The correct answer is Reproduction .

Key Points

• Living organisms have the ability to produce offspring through reproduction, ensuring the continuation of their species.
• Non-living entities do not engage in reproduction or produce offspring.

The correct answer is Capillaries.

Key Points:

• The smallest and most abundant blood vessels, capillaries, connect the arteries that take blood away from the heart and the veins that bring blood back to the heart (veins).
• The exchange of materials between the blood and tissue cells is the main purpose of capillaries.
• The metabolic activity of bodily tissues affects how capillaries are distributed.
• Because they are metabolically active and need a lot of oxygen and nutrients, tissues including skeletal muscle, the liver, and the kidney have vast capillary networks.

Additional Information:

• Blood arteries, which serve as conduits or channels, transport blood to human tissues.
• At the heart, two closed systems that resemble tubes begin and end.
• The pulmonary arteries are a single system that carry blood from the right ventricle to the lungs and back to the left atrium.
• The secondary system that moves blood from the left ventricle to the tissues all throughout the body before returning it to the right atrium is called the systemic veins.
  • Based on their shape and purpose, blood vessels are categorised as arteries, capillaries, or veins.

The correct answer is Ascorbic Acid

• Vitamin means 'vital for life'.
• Vitamin is an organic non-protein substance.
• Vitamins are compounds necessary for the healthy functioning of our bodies.
• We need vitamins to help us grow, to see correctly, as well as to help us battle infections.
• It is required by an organism for normal metabolic function but cannot be synthesized in sufficient quantity by that organism.
• They are also required in small quantities to prevent deficiency diseases.​

Key Points

Vitamin C:

• Ascorbic acid is the chemical name of vitamin C.
• Vitamin C is the first artificially synthesized vitamin.
• Vitamin C is essential for the healing of wounds, repair, and maintenance of cartilage, bone, and teeth.
• Vitamin C deteriorated through cooking and canning of food.
• Sources: citrus fruit, such as lemons, oranges and orange juice, amla, peppers, strawberries, blackcurrants, broccoli, sprouted pulses and potatoes.
• Scurvy is caused by the deficiency of Vitamin C
• It is a nutritional disorder mostly characterized by rashes or red spots on the skin.
• Muscle pain, body pain, fatigue and bleeding gums or tooth loss are other common symptoms of scurvy.

Important PointsCitric and Tartaric acid:

• They are weak organic acids.
• Usually encountered as a white solid.
• It occurs naturally in citrus fruits. 

• The myelinated axons are characterised by a covering of a fatty layer called the myelin sheath secreted by the Schwann cells.
• The myelin sheath is non-conducting. Therefore, small gaps are left between Schwann cells along the entire length of the axons.
• These gaps are called Nodes of Ranvier. They allow saltation of the nerve impulse.

The correct answer is Haemoglobin.

Key Points

• The Hemoglobin molecules with the help of external chemical factors take up oxygen molecules in the lungs and then send them to the various tissues of our body.

• Iron is the main constituent of hemoglobin.
• The normal level of hemoglobin is 13 to 17 grams per deciliter in men and 12.0 to 15.5 grams per deciliter in women.

Important Points

• Melanin is a dark biological pigment found in skin, hair, feathers, scales, eyes, and some internal membranes.
• Rhodopsin is called visual purple, a pigment-containing sensory protein that converts light into an electrical signal. 
• Bilirubin is a yellowish substance in your blood. It forms after red blood cells break down, and it travels through your liver, gallbladder, and digestive tract before being excreted.

Additional Information

• The biggest regulator of oxygen affinity in Hemoglobin is the oxygen itself.
• If in the lungs, the oxygen levels are high the Hemoglobin shows a greater affinity towards the oxygen molecules, and as it bounds to more oxygen, this property of affinity increases and vice versa.
• When the Oxyhemoglobin binds to the maximum capacity, it becomes saturated but its affinity towards oxygen increases whereas when this binding loose oxygen molecule the affinity decreases.
• This regulation activity is called Cooperativity and is an important function as it allows the maximum amount of Hemoglobin to be carried to the tissues and also allows deoxyhemoglobin which is releasing the oxygen tissue.

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

Additional Information

• 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.

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.

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, amylase, 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:

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 Calyx.

Key Points

• Flowers contain the plant’s reproductive structures.
• A typical flower has four main parts - or whorls - known as the calyx, corolla, androecium, and gynoecium.
• The outermost whorl of the flower has green, leafy structures known as sepals.
  • The sepals, collectively called the calyx, help to protect the unopened bud.

Important Points

• The second whorl is comprised of petals - usually, brightly coloured - collectively called the corolla.
• The number of sepals and petals varies depending on whether the plant is a monocot or dicot. 
  • In monocots, petals usually number three or multiples of three; in dicots, the number of petals is four or five, or multiples of four and five.
  • Together, the calyx and corolla are known as the perianth.
• The third whorl contains the male reproductive structures and is known as the androecium.
  • The androecium has stamens with anthers that contain the microsporangia.
• The innermost group of structures in the flower is the gynoecium, or the female reproductive component(s).
• The carpel is the individual unit of the gynoecium and has a stigma, style, and ovary.
  • A flower may have one or multiple carpels.

Concept:

• The cell is the basic unit of life. Life arises from pre-existing cells. Cells grow and multiply to form a diversity of life forms, this process of growth and multiplication of cells is called Cell Division.
• Cell division is of three types:

1. Mitosis - Equational division, occurs in somatic (non-sex) cells
2. Meiosis - Reducttional division, occurs in sex cells
3. Amitosis - Direct type of division, occurs in prokaryotes

• Meiosis can be further divided into two stages - Meiosis I and Meiosis II

Explanation:

• Prophase I of Meiosis I has 5 sub-stages
• Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis.
• The Zygotene stage is characterized by the pairing of homologous chromosomes called the ''Synapsis''
• The pairs of homologous chromosomes are called Bivalents.
• There develops a structure between the homologous chromosomes called the synaptonemal complex. It is a tripartite structure i.e. it is made up of 3 thick lines of DNA and protein.

Additional Information 

• Leptotene: During leptotene, the chromatin condenses to form the chromosomes. Chromosomes are the longest and thinnest in this stage.
• Pachytene: This stage is characterized by the occurrence of crossing over. Non-sister chromatids of the homologous chromosomes exchange their genetic parts. 
• Metaphase I: The first metaphase of meiosis characterized by the alignment of paired chromosomes along the center (metaphase plate) of a cell, which ensures that two complete copies of chromosomes are present in the resulting two daughter cells of meiosis I.