Biology is a high-scoring section in the General Awareness portion of SSC CGL, SSC CHSL, and Railway NTPC/Group D exams. This set of 30 practice questions covers two exam-critical areas — Cell Biology & Genetics and Animal Kingdom & Classification — with detailed explanations for every answer so you understand the concept, not just memorize the option. These questions are drawn from previously asked patterns and NCERT-level fundamentals commonly tested in competitive exams.
Cell Biology & Genetics
Question 1
Who is known as the 'Father of Microbiology' for being the first to observe and describe living microorganisms ('animalcules') under a microscope?
A) Robert Brown
B) Antonie van Leeuwenhoek
C) Purkinje
D) Rudolf Virchow
Correct Answer: B
Explanation: Antonie van Leeuwenhoek discovered free-living cells in pond water in 1674 and is widely recognized for his pioneering work in microscopy.
Question 2
Who coined the term 'Protoplasm' in 1839?
A) Purkinje
B) Schleiden
C) Schwann
D) Robert Brown
Correct Answer: A
Explanation: J.E. Purkinje named the fluid substance of the cell 'Protoplasm' in the year 1839.
Question 3
The famous cell theory principle 'omnis cellula e cellula' (new cells are formed from pre-existing cells) was published in 1855 by:
A) Schleiden and Schwann
B) Watson and Crick
C) Rudolf Virchow
D) Camillo Golgi
Correct Answer: C
Explanation: Rudolf Virchow expanded the cell theory by establishing that all cells arise from pre-existing cells.
Question 4
Which of the following is the smallest cell found in the human male body?
A) Neuron
B) Red Blood Cell
C) Sperm
D) Mycoplasma
Correct Answer: C
Explanation: In human males, the sperm cell is the smallest cell, whereas the neuron is the largest.
Question 5
The selectively permeable cell membrane, which acts as the 'bodyguard' of the cell, is primarily composed of:
A) Cellulose and Pectin
B) Proteins and Lipids
C) Peptidoglycan and Chitin
D) Nucleic acids and Carbohydrates
Correct Answer: B
Explanation: The cell membrane is a living, thin, elastic structure primarily composed of a bilayer of lipids embedded with proteins.
Question 6
What happens to an animal cell when it is placed in a hypotonic solution (where solute concentration is lower outside than inside)?
A) The cell shrinks.
B) The cell remains unchanged.
C) The cell swells.
D) The cell wall becomes rigid.
Correct Answer: C
Explanation: In a hypotonic solution, water moves into the cell through osmosis, causing the cell to swell and potentially burst.
Question 7
The phenomenon where a plant cell shrinks and its contents pull away from the cell wall when placed in a concentrated (hypertonic) solution is known as:
A) Diffusion
B) Plasmolysis
C) Endocytosis
D) Turgidity
Correct Answer: B
Explanation: When placed in a hypertonic solution, a plant cell loses water to its environment, leading to the shrinkage of the protoplast away from the cell wall (Plasmolysis).
Question 8
The cell wall of Fungi is primarily made up of which of the following complex sugars?
A) Cellulose
B) Peptidoglycan
C) Pectin
D) Chitin
Correct Answer: D
Explanation: Fungal cell walls are composed of Chitin, whereas plant cell walls are made of cellulose and bacterial cell walls are made of peptidoglycan.
Question 9
Which of the following statements accurately describes the 'Glycocalyx'?
A) It is a central vacuole in plant cells.
B) It is the inner porous membrane of mitochondria.
C) It is a surface slime layer that covers the cell membrane in bacteria.
D) It is a digestive enzyme found in lysosomes.
Correct Answer: C
Explanation: The Glycocalyx is an outer surface layer (often a capsule or slime layer) that provides protection to bacterial cells.
Question 10
Which cellular organelle, discovered by Robert Brown, is commonly referred to as the 'Brain of the Cell'?
A) Mitochondria
B) Nucleus
C) Golgi Bodies
D) Endoplasmic Reticulum
Correct Answer: B
Explanation: The Nucleus is known as the 'Brain of the Cell' because it houses the genetic material and controls all cellular activities.
Question 11
Inside the nucleoplasm, the nucleolus is primarily responsible for the formation of which cellular structure?
A) Chromosomes
B) Ribosomes
C) Lysosomes
D) Plastids
Correct Answer: B
Explanation: The nucleolus is the site of ribosomal RNA (rRNA) synthesis and the assembly of ribosomes.
Question 12
Chromosomes are thread-like structures visible during cell division. What are they primarily composed of?
A) RNA and Lipids
B) DNA and Histone proteins
C) Cellulose and Pectin
D) Carbohydrates and Fats
Correct Answer: B
Explanation: Chromosomes are composed of tightly coiled DNA molecules wrapped around structural packaging proteins called histones.
Question 13
Who discovered the double-helical structure of the DNA molecule in 1953?
A) Walther Flemming
B) Fredrick Miescher
C) Watson and Crick
D) Robert Brown
Correct Answer: C
Explanation: James Watson and Francis Crick established the double-helical model of DNA in 1953, utilizing data from Rosalind Franklin and Maurice Wilkins.
Question 14
Out of the 46 total chromosomes in a normal human cell, how many pairs are classified as autosomal chromosomes?
A) 22 pairs
B) 23 pairs
C) 1 pair
D) 46 pairs
Correct Answer: A
Explanation: Humans have 23 pairs of chromosomes: 22 pairs of autosomes (non-sex chromosomes) and 1 pair of sex chromosomes (XX or XY).
Question 15
Apart from the nucleus, which of the following organelles possesses its own distinct DNA and ribosomes?
A) Golgi bodies
B) Endoplasmic Reticulum
C) Mitochondria
D) Lysosomes
Correct Answer: C
Explanation: Mitochondria (and chloroplasts in plants) are semi-autonomous organelles containing their own loops of DNA and 70S ribosomes.
Question 16
Lysosomes are known as the 'suicidal bags' of the cell. Where are the digestive enzymes found inside lysosomes synthesized?
A) Smooth Endoplasmic Reticulum (SER)
B) Rough Endoplasmic Reticulum (RER)
C) Nucleolus
D) Peroxisome
Correct Answer: B
Explanation: The hydrolytic enzymes contained within lysosomes are synthesized by ribosomes attached to the Rough Endoplasmic Reticulum (RER).
Question 17
Which cell organelle is often referred to as the 'Post office of the cell' due to its role in the storage, modification, and packaging of products?
A) Mitochondria
B) Lysosomes
C) Golgi bodies
D) Ribosomes
Correct Answer: C
Explanation: The Golgi apparatus processes, sorts, packages, and routes proteins and lipids arriving from the endoplasmic reticulum.
Question 18
The characteristic red colour in tomatoes is imparted by which specific pigment found in chromoplasts?
A) Chlorophyll
B) Capsanthin
C) Lycopene
D) Melanin
Correct Answer: C
Explanation: Lycopene is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits.
Question 19
Among the types of Leucoplasts (colourless plastids), which one is specifically responsible for the storage of fats?
A) Amyloplast
B) Aleuroplast
C) Elaioplast
D) Chloroplast
Correct Answer: C
Explanation: Leucoplasts specialize by nutrient type: Amyloplasts store starch, Aleuroplasts store proteins, and Elaioplasts store lipids/fats.
Question 20
In which phase of the Cell Cycle does the synthesis or replication of DNA take place?
A) G1 phase
B) S phase
C) G2 phase
D) M phase
Correct Answer: B
Explanation: The 'S' (Synthesis) phase of interphase is dedicated entirely to replicating the genetic material of the cell.
Question 21
During the process of DNA replication, which enzyme is responsible for unwinding the DNA double helix?
A) Topoisomerase
B) DNA Ligase
C) DNA Polymerase
D) Helicase
Correct Answer: D
Explanation: Helicase breaks the hydrogen bonds between complementary base pairs to separate the two DNA strands, creating the replication fork.
Animal Kingdom & Classification
Question 22
Which of the following phyla of the Animal Kingdom exhibits complete asymmetry in their body structure?
A) Coelenterata
B) Porifera
C) Annelida
D) Echinodermata
Correct Answer: B
Explanation: Sponges (Phylum Porifera) lack any definitive symmetry plane, making them asymmetrical.
Question 23
The presence of only two germ layers (ectoderm and endoderm) separated by a jelly-like matrix called 'Mesoglea' is a characteristic feature of:
A) Platyhelminthes and Nematoda
B) Porifera, Coelenterata, and Ctenophora
C) Arthropoda and Mollusca
D) Annelida and Chordata
Correct Answer: B
Explanation: Diploblastic animals develop from two primary germ layers. Higher phyla from Platyhelminthes onward develop three layers (triploblastic).
Question 24
Which of the following groups of animals is described as 'Pseudocoelomate' (having a false body cavity)?
A) Platyhelminthes
B) Nematoda / Aschelminthes
C) Annelida
D) Arthropoda
Correct Answer: B
Explanation: Nematodes (roundworms) possess a body cavity that is not completely lined by mesoderm, known as a pseudocoelom.
Question 25
The 'Notochord' is a defining characteristic of the phylum Chordata. From which embryonic germ layer is this rod-like structure derived?
A) Ectoderm
B) Mesoderm
C) Endoderm
D) Mesoglea
Correct Answer: B
Explanation: The notochord is a flexible, rod-shaped structure that forms during early embryonic development from the mesodermal layer.
Question 26
True body segmentation (metameric segmentation) is primarily observed in which of the following sets of animal phyla?
A) Porifera, Coelenterata, and Platyhelminthes
B) Nematoda, Mollusca, and Echinodermata
C) Annelida, Arthropoda, and Chordata
D) Ctenophora, Aschelminthes, and Hemichordata
Correct Answer: C
Explanation: Metamerism is a linear series of body segments fundamentally similar in structure, characteristic of annelids, arthropods, and chordates.
Question 27
Animals belonging to the phylum Porifera have their bodies perforated with pores. What is the large central body cavity into which these pores open called?
A) Gastrovascular cavity
B) Spongocoel
C) Pseudocoelom
D) Coelom
Correct Answer: B
Explanation: Water enters a sponge through small outer pores (ostia) into a large central chamber called the Spongocoel before exiting via the osculum.
Question 28
Which of the following phyla possesses specialized stinging cells called 'Cnidoblasts' or 'Nematocysts'?
A) Ctenophora
B) Platyhelminthes
C) Coelenterata (Cnidaria)
D) Porifera
Correct Answer: C
Explanation: Coelenterates are called Cnidarians because they possess cnidocytes containing stinging organelles (nematocysts) used for prey capture and defense.
Question 29
Which exclusively marine phylum is well-known for showing 'bioluminescence' (the property of a living organism to emit light) and is commonly referred to as Sea Walnuts?
A) Coelenterata
B) Echinodermata
C) Ctenophora
D) Mollusca
Correct Answer: C
Explanation: Phylum Ctenophora (comb jellies or sea walnuts) consists entirely of marine organisms capable of emitting light via chemical reactions.
Question 30
Organisms of the phylum Platyhelminthes are dorsoventrally flattened and lack a true internal body cavity. Which specialized cells do they use for excretion and osmoregulation?
A) Malpighian Tubules
B) Nephridia
C) Flame Cells
D) Renette Cells
Correct Answer: C
Explanation: Flatworms (Platyhelminthes) utilize a simple excretory network composed of specialized ciliated cells called Flame Cells.
Key Takeaways
Antonie van Leeuwenhoek is regarded as the Father of Microbiology, while Rudolf Virchow established that all cells arise from pre-existing cells. Humans carry 23 pairs of chromosomes — 22 autosomal and 1 sex pair — and mitochondria are unique among organelles for carrying their own DNA. In the Animal Kingdom, Porifera (sponges) are asymmetrical and possess a spongocoel, while true segmentation (metamerism) is found only in Annelida, Arthropoda, and Chordata.
Frequently Asked Questions
Which topics of Biology are most important for SSC CGL and Railway exams?
Cell Biology, Genetics, Human Physiology, and Animal Kingdom classification are the most frequently asked Biology topics in SSC CGL, SSC CHSL, and Railway NTPC exams.
Who is known as the Father of Microbiology?
Antonie van Leeuwenhoek is known as the Father of Microbiology for being the first to observe living microorganisms under a microscope in 1674.
How many pairs of chromosomes do humans have?
Humans have 23 pairs of chromosomes in total: 22 pairs of autosomes and 1 pair of sex chromosomes.
How many questions come from Biology in SSC CGL Tier 1?
SSC CGL Tier 1 typically includes 2-4 Biology-based General Awareness questions, often focused on cell biology, human body systems, and classification of living organisms.