Test: General Science (Molecular Biology) - Software Development MCQ

The correct answer is option 2, i.e. Penicillin.

• Alexander Fleming was a Scottish microbiologist, physician, and pharmacologist who discovered the first antibiotic substance, Penicillin G from Penicillium notatum in 1928.
  • For this discovery, he received the Nobel Prize in Physiology or Medicine in 1945 along with Ernst Boris Chain and Howard Florey.
• The cell was discovered by Robert Hooke.
• Nucleus was discovered by Ernest Rutherford.
• DNA structure was discovered by Watson and Crick.

Concept:

The nucleus of the Cell

• The cell is the basic building block of all living beings. 
• The nucleus is the special structure located generally at the center of the cell. 
• The nuclear membrane separates the cytoplasm from the nucleus. 
• The nucleus contains a central part called nucleolus and chromosomes. 
• Chromosomes and nucleolus coexist in the nucleus. Chromosomes are not present in the nucleolus.

Chromosomes and Genes

• Chromosomes carry genes and help in the inheritance or transfer of characters from the parents to their children. 
• The chromosomes can be seen only when the cell divides.
• The credit for the discovery of chromosomes goes to Strasburger as he first described the chromosome structure seen in the nucleus during cell division.
• Usually, chromosomes are rod-shaped, elongated, or dot-like in shape with sizes varying from 0.5 to 32 micrometer.
• In humans, 23pairs of chromosomes are found i.e. 46 in numbers.

Conclusion:

• Chromosomes are present in the nucleus of the cell. So, all the given options are wrong. 
• The correct option is None of these.

Additional Information

• The cell membrane is also known as the plasma membrane. 
  • It is a porous structure that allows the exit and entry of certain materials according to its requirement. 
  • This is the major function of the cell membrane. 
• The cytoplasm is between the cell and the nucleus.
  • Cell organelles like mitochondria, Golgi bodies, ribosomes, etc. are present in the cytoplasm. 
  • Mitochondria is called the powerhouse of cells and is responsible for cellular respiration. 
  • vacuole is open space between cell which is used for storing food. 
• Plastids are double-membrane organelles found in the plant cell. They contain pigments that help the plant in photosynthesis. 

The correct answer is Cells of a tissue have similar Structure.

Cells: The cell is the basic structural, functional, and biological unit of all known organisms.

• There are different shapes of the cells.
• The size and shape of the cells might be different in different organism.
• Some cells have a nucleus (Eukaryotic cells) while the other does not have a defined nucleus (prokaryotic cells).

Tissues:  A tissue is a group of similar cells performing a specific function. These tissues further made organs and later organ system

⇒ The correct option in the above statements are - cells of tissue have a similar Structure.

• Charles Robert Darwin,in his book “The Origin of Species”, gave the Theory of Evolution by Natural Selection.
• Gregor Johann Mendel, also known as the father of genetics, gave the Law of Inheritance.
• The theory of origin of life on earth proposed by Haldane was confirmed by the experiments conducted by Stanley L. Miller and Harold C. Urey in 1953.

Bacteria are the sole members of the Kingdom Monera. They are the most abundant micro-organisms.
On the basis of origin, bacteria can be divided into two types - Archaebacteria & Eubacteria

Archaebacteria:

• These bacteria are special since they live in some of the harshest habitats such as extreme salty areas (halophiles), hot springs (thermoacidophiles) and marshy areas (methanogens).
• Archaebacteria differ from other bacteria in having a different cell wall structure and this feature is responsible for their survival in extreme conditions.
• For example - Methanogens are present in the gut of several ruminant animals such as cows and buffaloes and they are responsible for the production of methane (biogas) from the dung of these animals.

Additional Information

Eubacteria:

• There are thousands of different eubacteria or ‘true bacteria’.
• They are characterised by the presence of a rigid cell wall, and if motile, a flagellum.
• The Eubacteria can be both autotrophic & heterotrophic.

The correct answer is Thymine and Cytosine.

Key Points

• The pyrimidines in DNA are C & T. In RNA, U replaces T.

• Cytosine (C) formula is C₄H₅N₃O and Thymine (T) formula is C₅H₆N₂O₂.

Additional Information

• Deoxyribonucleic acid, commonly known as DNA, is the hereditary complex molecule present in humans and almost all other organisms.
• The information in DNA (double helix structure) is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T).
  • DNA has two base pairs, A-T and G-C, attached to a sugar-phosphate backbone.
• DNA is a long molecule that contains our unique genetic code.
  • It holds the instructions for making all the proteins in our bodies and the function of living things.
• In the cell nucleus, the DNA (deoxyribonucleic acid) molecule is packaged into thread-like structures called chromosomes.
  • A chromosome (microscopic structure) is made up of DNA tightly coiled many times around proteins called histones that support its structure.
  • A chromosome has two arms - a p arm (short arm) and a q arm (long arm), joined in the location of the centromere.

Important Points

• Watson and Crick Proposed the Double Helix structure of DNA with the two strands connected by hydrogen bonds.

Mitochondria

• Kolliker first observed mitochondria.
• Mitochondria are the site of aerobic respiration.
• Most of the oxidative metabolism and ATP production takes place in mitochondria.
• Mitochondria are called the powerhouse of the cell.
• Their organic compounds are broken down to release and store metabolic energy in the form of ATP molecules.

Chromoplast

• Plastids are found in all plant cells and in euglenoids.
• Based on the type of pigments plastids can be classified into chloroplasts, chromoplasts, and leucoplasts.
• The chloroplasts contain chlorophyll and carotenoid pigments which are responsible for trapping light energy essential for photosynthesis.
• Chlorophyll is the photosynthesis pigment.

Lysosome

• Lysosomes are membrane-bound structures.
• It is formed by the process of packaging in the Golgi apparatus.
• These enzymes are capable of digesting carbohydrates, proteins, lipids, and nucleic acids.
• Lysosome containing undigested material and eliminated.
• Lysosomes dispose of waste of the cell.

Golgi body 

• Golgi complex is made up of four parts - Cisternae, Tubules, Golgian vacuoles, and vesicles.
• The Golgi body gets the materials from E.R. through its cis-face.
• The materials are modified by the Golgi body.
• After modification, the materials are packed in vesicles.
• These vesicles are pinched off from the trans face of the Golgi body.

Therefore the correct option is  (a - ii, b - iv, c - i, d - iii).

The correct answer is ,

Key Points

• Both mitochondria and chloroplasts possess their own genetic material thus, they are called semi-autonomous organelles.
• The mitochondrial DNA and plastid DNA possess genes that produce the proteins necessary for the functioning of mitochondria and chloroplasts respectively.

Important Points

• Mitochondria (sing.: mitochondrion), unless specifically stained, are not easily visible under the microscope.
• The number of mitochondria per cell is variable depending on the physiological activity of the cells.
• In terms of shape and size also, a considerable degree of variability is observed.
• Typically it is sausage-shaped or cylindrical having a diameter of 0.2-1.0µm (average 0.5µm) and length 1.0-4.1µm.
• Each mitochondrion is a double membrane-bound structure with the outer membrane and the inner membrane dividing its lumen distinctly into two aqueous compartments, i.e. the outer compartment and the inner compartment.

The correct answer is Shark — Tortoise — Otter.

Key Points

• Shark - Scientists believe that sharks came into existence around 400 million years ago. It is believed that they descended from a small leaf-shaped fish that had no eyes, bones on fins.
  • These fish then evolved into two main groups of fish that are found today.
  • Bony fish and cartilaginous fish which include shark and Chimaira.
  • Sharks are on the top of the marine food chain and are the only huge marine reptiles that exist today.
• Tortoise is believed to have existed for 250 million years.
  • They belong to the reptile species of the family Testudinidae.
  • Tortoise has a hard shell to protect from the outside environment. They are believed to have evolved from very large body sizes of around 100 kgs. They are among the longest-living land animals in the world.
• Otters are believed to have existed on earth for the past 23 million years.
  • They have evolved significantly and have gone through many adaptations to survive till this time.

Additional Information

• They have the ability to move both on water and land except sea otters. The rest of the otters have webbed feet which help them to move in the water.
• They have five toes which help them to move on land as well. It is believed that they were once land animals only but they ended up going in the water to be safe from predators.
• It is also believed that the food sources were available in limited quantities on land so they started hunting in water to survive.

Explanation:

• Evolutionary biology: It is a field of science that deals with the study of evolutionary processes like natural selection, speciation & common descent that has led to the diversification of life on earth.
• Charles Darwin is known as the father of ''Evolutionary Biology''.
• Darwin proposed a theory of evolution called natural selection in the year 1859. According to it those populations which are a better fit (reproductively fit) in an environment will be selected by nature and will survive more.
• Charles Darwin wrote a book named ''The origin of species'' which is considered to be the foundation of evolutionary biology.

Additional Information 

• Herbert Spencer- He Was best known for the introduction and application of evolutionary theory to philosophy, psychology, and social sciences
• The famous phrase 'Survival of the fittest' to mean Natural Selection was coined by Herbert Spencer. He originated this phrase after the publication of famous biologist Charles Darwin’s book ‘Origin of Species’ which talked about ‘Natural Selection’.
• Julian Huxley was an English biologist, philosopher, educator, and author who greatly influenced the modern development of embryology, systematics, and studies of behaviour and evolution.
• Stanley Miller along with H.C. Urey provided experimental evidence of ''chemical evolution''