RBSE Solutions Class 11 Biology Chapter 36 Cockroach

RBSE Class 11 Biology Chapter 36 Multiple Choice Objective Questions

Question 1. Cockroach is
(a) Herbivorous
(b) Carnivorous
(c) Omnivorous
(d) Frugivorous
Answer: (c) Omnivorous
In simple words: Cockroaches eat many different kinds of food, including both plants and meat, so they are called omnivores.

🎯 Exam Tip: Remember that omnivores eat both plant and animal matter. Herbivores eat only plants, and carnivores eat only meat.

Question 2. The head of cockroach is formed by the fusion of how many segments?
(a) 5
(b) 6
(c) 7
(d) 8
Answer: (b) 6
In simple words: A cockroach's head is actually made up of six different parts that have joined together to form one solid structure.

🎯 Exam Tip: Knowing the number of segments in a cockroach's head is a key detail about its anatomy and a frequent question in exams.

Question 4. Exoskeleton of cockroach is made up of
(a) Chitin
(b) Cartilages
(c) Bones
(d) Keratin
Answer: (a) Chitin
In simple words: The tough outer covering of a cockroach, like its shell, is made from a material called chitin.

🎯 Exam Tip: Chitin is a common component of the exoskeletons of insects and crustaceans, providing protection and support.

Question 5. The Johnston organ found in the antennae are
(a) Gustoreceptors
(b) Olfactoreceptors
(c) Phonoreceptors
(d) Motion Receptor
Answer: (d) Motion Receptor
In simple words: The Johnston organ, located in a cockroach's antennae, helps it sense movement and vibrations around it.

🎯 Exam Tip: The Johnston organ is a specialized sensory structure, important for detecting air movement, sounds, and other physical vibrations.

Question 6. The mouth part is cockroach that functions like tongue
(a) Labium
(b) Hypopharynx
(c) Mandible
(d) Maxilla
Answer: (b) Hypopharynx
In simple words: The hypopharynx is a mouthpart in cockroaches that works like a tongue, helping them manipulate food.

🎯 Exam Tip: Understand the different mouthparts of insects and their specific roles, especially how they are adapted for feeding.

Question 7. Anal styles are found
(a) Only in male cockroach
(b) Only in female cockroach
(c) Both
(d) None
Answer: (a) Only in male cockroach
In simple words: Only male cockroaches have anal styles, which are small, pointed parts at the end of their body.

🎯 Exam Tip: Anal styles are a key external feature used to differentiate between male and female cockroaches.

Question 8. Th
(a) Coelom
(c)
Answer: (c)
In simple words: (Answer text is incomplete in the source. This question refers to an unknown biological structure.)

🎯 Exam Tip: Always pay attention to all provided options, even if the question text is short or unclear.

Question 9. Number of cuticular teeth in the gizzard of cockroach
(a) 4
(b) 6
(c) 8
(d) 10
Answer: (b) 6
In simple words: The gizzard, which helps grind food in a cockroach, has six hard, tooth-like structures.

🎯 Exam Tip: The gizzard's structure, specifically the cuticular teeth, is important for mechanical digestion in cockroaches.

Question 10. Hind gut in cockroach originates from
(a) Ectoderm
(b) Endoderm
(c) Mesoderm
(d) All of the options
Answer: (a) Ectoderm
In simple words: The hind gut of a cockroach develops from the outermost layer of embryonic tissue, called the ectoderm.

🎯 Exam Tip: Understand the embryonic origin (ectoderm, mesoderm, endoderm) of different organs, as this is a fundamental concept in developmental biology.

Question 11. Number of spiracles in cockroach
(a) 12 pairs
(b) 14 pairs
(c) 10
(d) 20
Answer: (c) 10
In simple words: Cockroaches have 10 pairs of small openings on their body called spiracles, which are used for breathing.

🎯 Exam Tip: Spiracles are part of the respiratory system in insects. Remember to specify if the number is in 'pairs' or total.

Question 12. The blood in cockroach is called is
(a) Lymph
(b) Haemolymph
(c) Haemoglobin
(d) None
Answer: (b) Haemolymph
In simple words: The fluid that circulates in a cockroach's body, similar to blood, is known as haemolymph.

🎯 Exam Tip: Insects have an open circulatory system where organs are bathed in haemolymph, which is different from the closed circulatory system in humans.

Question 13. Number of nerves in the peripheral nervous system of cockroach
(a) 10 pairs
(b) 20 pairs
(c)
(d) 40 pairs
Answer: (c)
In simple words: (Answer text is incomplete in the source. This question refers to the number of nerves in the peripheral nervous system.)

🎯 Exam Tip: The nervous system of insects is segmented, with ganglia in each segment connected by nerve cords.

Question 15. The excretory organs in cockroach
(a) Malpighii tubules
(b) Fat body cells
(c) Uricose glands
(d) All of the options
Answer: (d) All of the options
In simple words: Cockroaches use several parts, including Malpighian tubules, fat body cells, and uricose glands, to remove waste from their bodies.

🎯 Exam Tip: Excretion in cockroaches involves multiple organs, highlighting a complex system for waste removal.

Question 16. The hormone ecdysone which controls ecdysis is secreted by
(a) Corphora allata
(b) Neurosecretory cells
(c) Prothoracic glands
(d) Brain
Answer: (c) Prothoracic glands
In simple words: Ecdysone, the hormone that helps cockroaches shed their skin (ecdysis), is released by the prothoracic glands.

🎯 Exam Tip: Hormones play a crucial role in insect growth and development, with ecdysone being central to the molting process.

Question 17. The structural & functional unit of compound eye in cockroach
(a) Ommatidium
(b) Cornea
(c) Retina
(d) Rhabdone
Answer: (a) Ommatidium
In simple words: The compound eye of a cockroach is made up of many small units, each called an ommatidium, which helps it see.

🎯 Exam Tip: Compound eyes in insects are composed of numerous ommatidia, each acting as a separate visual receptor, contributing to a mosaic image.

Question 18. Which of the following is a gland of female reproductive system
(a) Phallic glad
(b) Mushroom gland
(c) Colleterial gland
(d) Uricose gland
Answer: (c) Colleterial gland
In simple words: The colleterial gland is an important part of the female cockroach's reproductive system.

🎯 Exam Tip: Colleterial glands secrete substances that form the ootheca (egg case) in female cockroaches.

Question 20. The young cockroach is called as
(a) Nymph
(b) Maggot
(c) Periblastula
(d) Imago
Answer: (a) Nymph
In simple words: A baby cockroach, before it becomes a full-grown adult, is known as a nymph.

🎯 Exam Tip: Nymphs are immature stages of insects that undergo incomplete metamorphosis, resembling smaller versions of the adults without wings.

RBSE Class 11 Biology Chapter 36 Very Short Answer Questions

Question 2. Give the number of segments in cockroach during embryonic & adult stages.
Answer: During the embryonic stage, a cockroach has 20 segments, but as an adult, it has 19 segments.
In simple words: A cockroach starts with 20 body parts when very young and ends up with 19 as an adult.

🎯 Exam Tip: It is crucial to specify the stage (embryonic vs. adult) when discussing the number of segments, as it changes during development.

Question 3. Where the Johnston organs are found? Give their function.
Answer: Johnston's organs are found in the antennae of the cockroach. Their function is to act as motion receptors, helping the cockroach sense movement.
In simple words: These organs are in the feelers (antennae) and help the cockroach detect if things are moving.

🎯 Exam Tip: Remember that Johnston's organ is primarily involved in sensing vibrations and movements in the air or water, crucial for orientation and communication.

Question 4. Which type of mouth parts are found in Cockroach?
Answer: Cockroaches have biting and chewing type mouthparts, which are designed for breaking down solid food.
In simple words: Cockroaches have mouthparts that let them bite and chew their food.

🎯 Exam Tip: Classify insect mouthparts based on their function (e.g., biting-chewing, sucking, sponging) and relate them to the insect's diet.

Question 5. Give the role of anal cerci found in the cockroach.
Answer: The anal cerci in cockroaches function as phonoreceptors, helping them detect sounds and vibrations.
In simple words: Anal cerci on a cockroach's rear end help it hear sounds and feel movements.

🎯 Exam Tip: Anal cerci are sensory appendages sensitive to air currents and vibrations, allowing cockroaches to detect predators quickly.

Question 6. What is the number of legs in cockroach and how many segments are found in each leg.
Answer: A cockroach has 3 pairs of legs, which means a total of 6 legs. Each leg is made up of 5 different types of segments, resulting in 9 segments per leg overall.
In simple words: Cockroaches have six legs. Each leg has nine parts made of five different types of segments.

🎯 Exam Tip: Always specify the number of legs in pairs and clarify the number and types of segments in each leg.

Question 7. Why the body cavity of cockroach is not called as true coelom?
Answer: The body cavity of a cockroach is not considered a true coelom because it is not completely lined by mesoderm.
In simple words: A cockroach's body space is not a "true" coelom because it doesn't have a full lining from a specific body tissue layer (mesoderm).

🎯 Exam Tip: A true coelom is entirely lined by mesoderm, whereas a pseudocoelom is only partially lined, and an acoelomate has no body cavity.

Question 8. Give the food of cockroach?
Answer: Al
In simple words: (The answer text is incomplete in the source. Cockroaches are omnivores and eat various organic materials.)

🎯 Exam Tip: When asked about an animal's food, it is best to describe its feeding habits, for example, whether it is a herbivore, carnivore, or omnivore.

Question 10. What is the number of spiracles in cockroach.
Answer: There are 3 spiracles in a cockroach.
In simple words: A cockroach has three tiny holes on its body for breathing.

🎯 Exam Tip: Be careful with details like 'pairs' versus total number when referring to structures like spiracles.

Question 11. What is the number of ganglia in the ventral nerve cord?
Answer: The ventral nerve cord of a cockroach contains 9 ganglia, which are organized as 3 in the thorax and 6 in the abdomen.
In simple words: The main nerve cord in a cockroach has nine nerve clusters, three in the chest area and six in the belly area.

🎯 Exam Tip: The segmented nature of the nervous system, with ganglia in each segment, is characteristic of arthropods like cockroaches.

Question 12. Write the main excretory organ in cockroach.
Answer: The primary excretory organs in a cockroach are the Malpighian tubules.
In simple words: Malpighian tubules are the main body parts that help the cockroach get rid of waste.

🎯 Exam Tip: Malpighian tubules are key structures in insect excretion, playing a role similar to kidneys in vertebrates.

Question 13. How many ommatidia are found in each compound eye of cockroach?
Answer: Each compound eye of a cockroach contains approximately 2000 ommatidia.
In simple words: A cockroach's eye is made of about 2000 tiny seeing units, called ommatidia.

🎯 Exam Tip: The large number of ommatidia in compound eyes allows for a wide field of vision, although the image formed is a mosaic.

Question 14. What is the role of phallic gland in the cockroach?
Answer: The phallic gland in a cockroach secretes the outermost covering of the spermatophore, which is a packet of sperm.
In simple words: The phallic gland makes the outer layer of the sperm packet in a cockroach.

🎯 Exam Tip: Spermatophores are important in insect reproduction for transferring sperm; the phallic gland's role is critical in its formation.

Question 15. How many times cockroach moults during metamorphosis?
Answer: During its metamorphosis, a cockroach typically moults between 7 to 10 times.
In simple words: A cockroach sheds its skin about 7 to 10 times as it grows.

🎯 Exam Tip: Molting (ecdysis) is essential for insect growth, as their exoskeleton does not expand. The number of molts can vary by species and environmental conditions.

RBSE Class 11 Biology Chapter 36 Short Answer Questions

Question 2. Describe in brief the mouth parts in cockroach.
Answer: Cockroaches have biting and chewing mouthparts, also known as mandibulated mouthparts. These are located around the mouth, under the head. They form a space in front of the mouth called the pre-oral cavity, which is divided into two main parts:
1. Salivarium
2. Cibarium
In simple words: Cockroaches have mouth parts that help them bite and chew. These parts, including the salivarium and cibarium, are located around their mouth.

🎯 Exam Tip: When describing mouthparts, always mention their type (e.g., biting-chewing) and list the main components involved in feeding.

Question 3. Differentiate male & female cockroach.
Answer:

In simple words: Male and female cockroaches look different. Males are usually shorter with longer wings and have special parts called anal styles, while females are longer, have shorter wings, and no anal styles.

🎯 Exam Tip: Focus on clear, distinct morphological features like body length, abdomen shape, presence/absence of anal styles, and wing length for accurate differentiation.

Question 5. Draw a labelled diagram of alimentary canal.
Answer: The labelled diagram of the alimentary canal of a cockroach is shown below.

In simple words: The picture above shows the different parts of a cockroach's digestion system, like its stomach and intestines.

🎯 Exam Tip: Practice drawing and labeling each part of the alimentary canal clearly, understanding the flow of food through them. Pay attention to structures like hepatic caecae and Malpighian tubules.

Question 6. Explain in brief the process of respiration in cockroach.
Answer: Respiration in cockroaches involves the contraction and relaxation of tergosternal muscles. When these muscles contract, air is pushed out (expiration). When they relax, pressure inside the trachea decreases, causing air to rush in through spiracles (inspiration). During rest, breathing happens automatically. During active periods, it's a controlled process. Gases exchange through diffusion between the tracheole fluid and tissue fluid.
In simple words: Cockroaches breathe by moving special muscles in their body. These movements push air out and pull fresh air in through tiny holes called spiracles. Air goes in when muscles relax and out when they tighten.

🎯 Exam Tip: Highlight the role of tergosternal muscles, spiracles, and diffusion in the respiratory process. Mentioning the difference between breathing at rest and during activity can also fetch marks.

Question 7. Draw a labelled diagram of blood sinuses in cockroach.
Answer: A labelled diagram showing the blood sinuses in a cockroach is provided below.

In simple words: The diagram above shows how blood flows inside a cockroach, highlighting the different spaces (sinuses) and the heart.

🎯 Exam Tip: Accurately label the dorsal and ventral diaphragms, pericardial, perivisceral, and perineural sinuses, and the tubular heart with its ostia.

Question 8. Explain in brief die central nervous system in cockroach.
Answer: The central nervous system of a cockroach consists of a nerve ring and a ventral nerve cord. The nerve ring is located in the head, surrounding the esophagus. It includes a pair of supra-oesophageal ganglia (the brain), circum-oesophageal connectives, and a pair of sub-oesophageal ganglia. The brain is a bilobed structure formed by the fusion of three pairs of ganglia and has parts like the Protocerebrum.
In simple words: The cockroach's main nervous system has a nerve ring in its head, which acts like a brain, and a nerve cord running along its belly. The head nerve ring is made of different nerve clusters joined together.

🎯 Exam Tip: Focus on the two main components (nerve ring and ventral nerve cord) and the key ganglia that form the "brain" and its position relative to the esophagus.

Question 9. Where the Malpighian tubule are situated in cockroach? How they function?
Answer: Malpighian tubules are located at the junction of the midgut and hindgut in cockroaches, typically 72 to 90 tubules arranged in 6 groups. They are long, narrow, yellow, and unbranched, suspended in the haemolymph. Each tubule is about 26 mm long and 0.5 mm in diameter, with thick walls made of 6 large cuboidal cells. The lumen is narrow, ciliated, or brush-bordered, surrounded by a peritoneum.
Physiology: Each Malpighian tubule has two parts: a proximal absorptive part and a distal secretory part. The distal part absorbs CO\(_{2}\), H\(_{2}\)O, sodium urates, and potassium urates from the haemolymph. Inside the lumen, CO\(_{2}\) and H\(_{2}\)O react to form H\(_{2}\)CO\(_{3}\), which then breaks into H\(^{+}\) and HCO\(_{3}^{–}\). Similarly, sodium and potassium urates ionize into Na\(^{+}\), K\(^{+}\), and urate ions. These ions react to form uric acid, sodium bicarbonate, and potassium bicarbonate, which are then excreted.
In simple words: Malpighian tubules are found where the cockroach's stomach meets its intestines. They work like tiny kidneys, taking waste products and water from the blood (haemolymph) and turning them into uric acid and other substances to be removed from the body.

🎯 Exam Tip: Detail the location, structure, and the two-part function of Malpighian tubules. Emphasize the chemical process of waste conversion (especially urates to uric acid) as a key part of their physiology.

Question 10. Write short notes on
1. Apposition image
2. Superposition image
Answer:
1. Apposition image: This type of image is formed in moderate to bright light. It is also known as a mosaic image. The pigmented sheaths expand, optically isolating each ommatidium in bright light. This means that each ommatidium forms an image of only one part of the object, resulting in a distinct image. In cockroaches, only mosaic vision is formed. The
In simple words: (The answer text is incomplete in the source. Apposition images are formed in bright light, where each small eye unit sees only a small part of the whole picture.)

🎯 Exam Tip: For short notes, define the concept, explain the conditions under which it occurs (e.g., light intensity), and briefly describe the mechanism (e.g., optical isolation) and resulting image type.

Question 11. Draw labelled diagram of male reproductive organs of cockroach.
Answer: The labelled diagram of the male reproductive organs of a cockroach is presented below.

In simple words: This picture shows all the parts of the male cockroach's body that help it reproduce, including the testes and various glands.

🎯 Exam Tip: Ensure all key organs—testes, vas deferens, seminal vesicles, mushroom gland (including its tubules), ejaculatory duct, and phallic gland—are correctly drawn and labelled.

Question 12. Draw labelled diagram of female reproductive organs in cockroach.
Answer: The labelled diagram of the female reproductive organs of a cockroach is provided below.
In simple words: This diagram shows all the organs inside a female cockroach that are used for reproduction, including the egg-laying parts.

🎯 Exam Tip: Clearly label the ovaries (with ovarioles), oviducts, common oviduct, colleterial glands, oothecal chamber, and ovipositor. Understanding their connections is vital.

Question 13. Explain formation of ootheca in cockroach.
Answer: Formation of Ootheca: During ootheca formation, ovipositors push fertilized eggs into the oothecal chamber, arranging them in two rows of eight eggs each. The collateral glands then secrete a dark brown, hard covering around these fertilized eggs within the oothecal chamber. This entire structure is called the ootheca, and its formation takes about 20 hours. The ootheca is 8-10 mm long, with one end being serrated. A female cockroach can produce 20-40 oothecae in her lifetime. She carries the ootheca for a few days before depositing it in a dark, dry, and warm place. Each egg inside the ootheca is centrolecithal, covered by a chitinous shell, and has a tiny micropyle for sperm entry.
In simple words: A female cockroach creates an egg case called an ootheca. She places fertilized eggs into a chamber, and special glands cover them with a hard, brown shell. This case protects the eggs until they hatch.

🎯 Exam Tip: Explain the process chronologically, mentioning the role of ovipositors, collateral glands, the structure of the ootheca, and the conditions for its deposition.

Question 14. Explain structure of function of mushroom gland in cockroach.
Answer: M
In simple words: (The answer text is incomplete in the source. The mushroom gland is part of the male reproductive system, involved in forming the spermatophore and providing nutrients.)

🎯 Exam Tip: For glands in reproductive systems, describe their location, structure (e.g., types of tubules), and specific secretions or functions (e.g., forming parts of spermatophores, providing nourishment).

Question 15. Explain in brief the copulation & fertilization in cockroach.
Answer:
Copulation: Cockroaches mate at night in a tail-to-tail position, a process that typically lasts for one hour. Mating occurs during the breeding season, which usually runs from March to September. During copulation, the male uses phallomeres to open the female's gonopore and inserts a spermatophore into the genital chamber. This spermatophore attaches to the spermathecal papilla, and the sperms are stored in the spermathecae for about 20 hours. The male is attracted to the female by a pheromone she secretes. After use, the empty spermatophore is ejected and sometimes eaten by other cockroaches.
Fertilization: After copulation, 16 ova (eggs) are released from both ovaries into the oothecal chamber. The female's ovipositors carefully arrange these ova into two rows, with 8 eggs in each row. Then, sperms are released from the spermathecae onto the ova, and fertilization takes place within the genital chamber.
In simple words: Cockroaches mate tail-to-tail at night. The male gives a sperm packet (spermatophore) to the female, which stores the sperm. Later, the female lays eggs, and these stored sperm fertilize them in her body.

🎯 Exam Tip: Remember to clearly distinguish between copulation (mating process) and fertilization (joining of sperm and egg), and mention key structures like the spermatophore and ootheca.

RBSE Class 11 Biology Chapter 36 Essay Type Questions

Question 1. Describe in detail the morphology of cockroach.
Answer:
Shape, Size and Colour: The cockroach has a body that is flat from top to bottom (dorso-ventrally flat) and is symmetrical on both sides (bilaterally symmetrical). Its color is dark brown. It measures about 2 to 4 cm in length and 1 to 1.5 cm in width. There are two black spots visible on the top side of the pronotum, which is a part of its thorax.

Sexual Dimorphism: Cockroaches show clear differences between males and females in their external features. These differences help to tell them apart:

Head: The head is connected to the thorax at a 90° angle by a thin, flexible neck. It is triangular and pear-shaped, positioned facing downwards (hypognathus). The head is made from 6 fused segments. It has one pair of black, kidney-shaped compound eyes. Near these compound eyes, there are also simple eyes (ocellar spots or ocelli), which are less developed and non-functional for image formation but sensitive to light. The cockroach also has a pair of movable antennae located in sockets on the head. Each antenna has three parts:

• Scape: This is the base part that connects to the head.
• Pedicel: This middle part contains Johnston's organ, which helps in sensing antennary movements.
• Flagellum: This is a long, thread-like structure made of many segments, equipped with touch receptors (thigmoreceptors) and smell receptors (olfactoreceptors).

A labelled diagram showing the dorsal view of a cockroach, including its head, thorax, and abdomen, as well as an anterior view of the head, should be drawn here.

Thorax: The thorax makes up about 2/5 of the body and has three segments: prothorax, mesothorax, and metathorax. It carries three pairs of legs and two pairs of wings. It also has two pairs of spiracles (small openings for breathing) located on the sides of the pro-mesothorax and meso-metathorax. A labelled diagram showing the ventral view of a cockroach, including its legs and anal styles/cerci, should be drawn here.

Abdomen: In the embryonic stage, the abdomen has 11 segments, but in adults, it has 10. It is not used for movement. The first eight abdominal segments each have 8 pairs of spiracles. The first abdominal segment is the smallest. There are scent glands between the 5th and 6th abdominal segments whose secretions help keep enemies away and act as a sex attractant. The abdomen has a pair of anal cerci, attached to the 10th tergite in both males and females. These are long, thin, 15-segmented structures with sound receptors (phonoreceptors). Male cockroaches also have a pair of small, pointed anal styles on the 9th sternite, which are unsegmented and help during mating. The anus is located at the end of the 10th segment in both sexes, bordered by four chitinous plates: one epiproct, one hypoproct, and two paraprocts. These are considered remnants of the 11th abdominal segment.

Skeleton: The cockroach has both an outer skeleton (exoskeleton) and an inner skeleton (endoskeleton).

• Exoskeleton: The body is covered by a dark brown, chitinous exoskeleton, which is a hard carbohydrate made of glycosamine. Each body segment's exoskeleton is called a sclerite and consists of four plates:
  • Tergum: A large, dorsal (top) plate.
  • Sternum: A small, ventral (bottom) plate.
  • Pleura: Two small, lateral (side) plates.
  These sclerites are connected by a thin, flexible articular or arthrodial membrane. Chitin gives hardness to the exoskeleton.
• Exoskeleton of Head: The head capsule is formed by the fusion of six sclerites and contains 6 chitinous plates. The top of the head is called the vertex, which is divided into two halves.
• Exoskeleton of Neck: The neck has 4 chitinous cervical plates: two dorso-lateral and two ventro-lateral.
• Exoskeleton of Thorax: The sclerites of the prothorax, mesothorax, and metathorax are called pronotum, mesonotum, and metanotum, respectively. The pronotum is the largest.
• Exoskeleton of Abdomen: The abdomen has 10 relatively thin sclerites. In males, the 7th tergite covers the 8th tergite, and the 7th sternite covers the 8th sternite. In females, the 7th tergite covers the 8th and 9th tergites, and the 7th sternite covers the 8th and 9th sternites. In both sexes, the 10th tergite is large and two-lobed at the back.
• Endoskeleton: The endoskeleton provides attachment points for muscles. The head has a tent-like endoskeleton called a tentorium, which has an opening (foramen) for nerves. In the thorax, the internal projections of the exoskeleton are called apodemesi or phragma, of which there are three:
  • First phragma: Between the pronotum and mesonotum.
  • Second phragma: Between the mesonotum and metanotum.
  • Third phragma: Between the metanotum and the first abdominal segment.
  The ventral apodemes in the thorax are Y-shaped and called furca.

A labelled diagram showing the anterior view of the cockroach head (Fig. 36.3) should be drawn here.

Mouth Parts: Cockroaches have biting and chewing mouth parts, also known as mandibulated mouth parts. These are attached around the mouth, ventral to the head, enclosing a pre-oral cavity, which has two parts: Salivarium and Cibarium. The various parts include:

• Labrum: This is a movable, rectangular upper lip that covers the mouth parts from the front. Its inner surface has gustatory (taste) hairs.
• Mandibles: There is a pair of mandibles attached laterally below the labrum. Each is triangular with a broad base, moved by abductor muscles. Their inner ends have denticles for cutting and chewing food. A pad-like structure called the prostheca, bearing touch receptors (tangoreceptors), is at the inner basal end.
• First Maxillae: A pair of first maxillae are attached laterally below the mandibles. Their base is called the cardo, attached to the head capsule by muscles. The distal end of the cardo is attached to a stipes, which in turn connects to an inner lacinia and an outer galea. These help clean antennae and legs, and the lacinia also helps hold food during feeding.
• Labium (Second Maxillae): Formed by the fusion of a pair of second maxillae. Its proximal part, the postmentum, divides into a submentum and mentum. The distal part is the prementum, which has a pair of palpiger plates with 3-jointed labial palps. The prementum's distal end has a pair of glossae (inner) and paraglossae (outer), which help keep food particles in the pre-oral cavity.
• Hypopharynx or Lingua: A small, non-chitinous, cylindrical structure that acts like a tongue, attached to the common salivary duct in the pre-oral cavity.

A labelled diagram showing the different mouth parts (mandible, first maxilla, labium) should be drawn here.

Legs: Cockroaches have three pairs of legs, each consisting of 9 segments: coxa, trochanter, femur, tibia, and tarsus. Each leg also has a pulvillus between the claws, and an arolium (a porous pad-like structure). The claws help in movement on rough surfaces, while the arolium and plantulae (pads) aid in movement on smooth surfaces.
A labelled diagram showing a cockroach leg (Fig. 36.5) should be drawn here.

Wings: Cockroaches have two pairs of wings, attached to the dorsal-lateral sides of the mesothorax and metathorax. The first pair, called tegmina or elytra, are thick, hard, and leathery, covering the second pair of wings when at rest. The second pair of wings are thin, transparent, and membranous, also folded beneath the first pair when at rest. Wings have a network of veins that once contained haemolymph, which later dries up, making the veins act as an endoskeleton (nervures). Wings form as outgrowths of the body wall between the tergum and pleuron, with only two layers of cuticle in well-developed wings. The base of each wing attaches to the sternum with a basilar muscle. Tergosternal muscles in each thoracic segment (also called dorso-ventral muscles) connect the tergum and sternum. The movement of wings is controlled by the contraction and relaxation of these basilar and tergosternal muscles.

Digestive System: The cockroach has a digestive system that includes an alimentary canal and salivary glands.

Alimentary Canal: This is a simple tube divided into three main parts:

• Foregut (Stomodaeum): Originates from the ectoderm and is lined with cuticle. It includes the mouth, oesophagus, crop, and gizzard.
• Midgut (Mesenteron): Originates from the endoderm.
• Hindgut (Proctodaeum): Originates from the ectoderm and is lined with cuticle. It includes the ileum, colon, rectum, and anus.

The parts of the alimentary canal are as follows:

• Mouth: Located at the base of the pre-oral cavity, it leads directly into the oesophagus.
• Oesophagus: A narrow, simple tube in the neck and prothorax, folded internally.
• Crop: A thin-walled, elastic, bag-like structure in the mesothorax, metathorax, and the first 3 or 4 abdominal segments. Its wall is flexible.
• Gizzard (Proventriculus): A small, thick-walled, hard, conical structure in the abdomen, surrounded by circular muscles. Its cavity is lined with cuticle, forming an anterior armarium with 6 chitinous, cuticular teeth. Six longitudinal grooves alternate with the teeth, equipped with muscles and bristles, acting as a strainer. The posterior part is funnel-shaped with pads of bristles and extends into the midgut as a stomodaeal valve, preventing food from re-entering the foregut.
• Mesenteron: The soft, delicate part of the alimentary canal (1/3 of its length). Its anterior part, called the cardia, receives 6 to 8 hepatic caecae. The hepatic caecae are attached at the junction between the foregut and midgut.
• Hepatic Caecae: These are thin, blind, yellowish tubes that secrete digestive enzymes. The anterior half of the midgut is secretory, and the posterior half is absorptive.
• Ileum: A small, narrow tube with many internal spines, lined by cuticle, connecting the midgut to the hindgut. It absorbs remaining digested food after spines tear the peritrophic membrane.
• Colon: A long, broad tube that is coiled without spines.
• Rectum: The final part, opening to the outside via the anus, is small, broad, and has 6 longitudinal rectal papillae (pad-like structures) bounded by a thin cuticle. It absorbs most of the water.

A labelled diagram showing the alimentary canal of a cockroach (Fig. 36.7) should be drawn here. A labelled diagram showing the transverse section of the gizzard (Fig. 36.8) should be drawn here.

Salivary Glands: A pair of salivary glands are located in the thorax on either side of the crop. Each gland is two-lobed in its anterior 1/3 part and produces a salivary duct. These ducts join to form a common salivary duct. The salivary glands secrete saliva. There are also paired reservoirs, or receptacles, which are thin-walled, transparent sacs storing saliva. Each reservoir has a duct, which joins its counterpart to form a common reservoir duct. This common reservoir duct then joins the common salivary duct.
A labelled diagram showing the salivary gland of a cockroach (Fig. 36.9) should be drawn here.

Digestion Process: The cockroach is an omnivorous animal with biting and chewing mouth parts. Food in the pre-oral cavity mixes with saliva containing mucus and enzymes like amylase, chitinase, and cellulase, making the food slimy. Amylase, chitinase, and cellulase begin digesting carbohydrates. The partly digested food goes to the crop, where it mixes with hydrolases (invertase, maltase, lactase, trypsin, lipase) secreted by the hepatic caecae for semi-digestion. This food then enters the gizzard for grinding and filtering fine particles into the midgut. A peritrophic membrane, made of protein and chitin, surrounds the semi-digested food in the midgut. This membrane is permeable to digested food and hydrolases but protects the soft midgut from hard food particles. The secretory part of the midgut releases various hydrolases to complete digestion, and most digested food is absorbed here. In the ileum, spines tear the peritrophic membrane for further absorption. The colon absorbs water, but most water is absorbed by the rectal papillae in the rectum. Fecal matter is digested into small, dry pellets.
In simple words: The morphology of a cockroach describes its body parts and how they look. This includes its flat, brown body, head (with eyes and antennae), thorax (with legs and wings), and abdomen. It also covers its hard outer skin (exoskeleton), internal supports (endoskeleton), mouth parts for chewing, and the whole digestive system which breaks down food and absorbs nutrients. Males and females have slight differences in their body shape and certain appendages.

🎯 Exam Tip: When describing morphology, ensure you cover external features, appendages (legs, wings, antennae), and main internal systems (digestive, respiratory, nervous, reproductive) with their key structures. Use clear headings and bullet points for an organized answer.

Question 3. Explain respiratory system in cockroach. Draw labelled diagram.
Answer:
Respiratory System: The respiratory system of a cockroach is made up of a network of tubes called tracheae, which open to the outside through small holes called spiracles. A labelled diagram showing the process of respiration in the trachea and trachioles (Fig. 36.14) should be drawn here. This diagram should illustrate the structure of the spiracles, tracheae, and the finer trachioles involved in gas exchange.

Spiracles: Cockroaches have 10 pairs of spiracles, also known as stigmata. The first two pairs are found on the side-front of the pro/mesothorax and meso/metathorax. The first pair of abdominal spiracles is located on the top-side of the first abdominal segment. The remaining seven pairs of spiracles are found on the side-front of the 2nd to 8th abdominal segments. Each spiracle is oval-shaped and surrounded by a chitinous ring called a peritreme. They have ciliary bristles that filter incoming air. The thoracic spiracles are larger than the abdominal ones. The first thoracic and first abdominal spiracles stay open permanently. The other spiracles only open during inspiration and have valves. Each spiracle leads into a small chamber, which is a tracheal chamber or atrium, meaning there are 10 pairs of atria.

Trachea: The tracheae are also known as windpipes and originate from the ectoderm. They consist of three pairs of longitudinal tracheal trunks:

• Dorso-lateral tracheal trunk (1 pair)
• Lateral tracheal trunk (1 pair)
• Ventro-lateral tracheal trunk (1 pair)

The 10 atria on one side open into the ventro-lateral tracheal trunks on that same side. All six longitudinal tracheal trunks are connected by transverse tracheae in each segment. These trunks branch into smaller tracheae, which are thin-walled, elastic, and silvery-white tubes. Their walls are supported by spiral rings made of chitin. Each trachea ends in a trachiole cell, which gives rise to 3 to 5 intracellular tubules called trachioles. These trachioles are very fine, about 1 micron in diameter, and are also silvery-white with walls supported by spiral rings of trachin. During rest, the trachioles are closed and filled with trachiole fluid, which aids gas exchange. The lining of the trachiole is called intima.

Mechanism of Respiration: Respiration in cockroaches involves the contraction and relaxation of tergosternal muscles. When these muscles contract, air is pushed out (expiration). When the tergosternal muscles relax, the pressure inside the trachea decreases, causing air to rush into the body through the spiracles (inspiration). At rest, breathing is involuntary, but during active phases, it becomes a voluntary process. Gas exchange happens through diffusion between the trachiole fluid and the tissue fluid.
In simple words: Cockroaches breathe using tiny tubes called tracheae that open to the outside through small holes called spiracles. Air goes in and out through these holes. Their breathing muscles help push air in and out. Inside, very fine tubes called trachioles exchange oxygen and carbon dioxide with their body.

🎯 Exam Tip: When explaining the respiratory system, always mention the spiracles, tracheae, and trachioles. For the mechanism, highlight the role of tergosternal muscles in controlling air movement. Remember to include a clear, labelled diagram of the respiratory system showing these components.

Question 4. Draw labelled diagram of heart in cockroach and explain its physiology.
Answer: The cockroach has a heart that looks like a tube and beats. It is located in the middle of the back, inside the pericardial sinus. This heart has 13 chambers, with 3 in the chest area (thorax) and 10 in the belly area (abdomen). The back end of the heart is closed. The front of the heart opens into a main artery (anterior aorta) that leads into the head area. Each heart chamber is shaped like a funnel and has two side openings called ostia. Blood from the pericardial sinus flows into the heart through these ostia. Inside the heart, blood flows from back to front. The first heart chamber is the biggest, and the last one is the smallest. The cockroach heart's beating is controlled by nerves (neurogenic), and it beats about 49 times per minute. The blood moves around the cockroach's body with the help of alary muscles and the beating heart. When the heart contracts (systole), blood is pushed out. When it relaxes (diastole), blood from the perivisceral sinus enters the pericardial sinus and then flows into the heart through the lateral ostia.
In simple words: The cockroach heart is a tube with 13 chambers that beats to pump blood. Blood enters through small side openings and flows forward, helping the cockroach's body get nutrients.

🎯 Exam Tip: When asked to explain physiology, always describe the structure first, then the function and mechanism, including any specific terms like systole and diastole.

Question 6. Explain male / female reproductive system in cockroach.
Answer: The cockroach is a creature that has separate male and female individuals, which means it shows sexual dimorphism.
Male Reproductive Organs:
The male cockroach has several parts for reproduction:
1. **Testes:** There is a pair of testes located in the 4th, 5th, and 6th segments of the abdomen. Each testis has three lobes, and each lobe contains 20 small tubes (tubular lobules).
2. **Vas Deferens:** Each testis connects to a vas deferens. Both vas deferens open separately at the bottom of the mushroom gland.
3. **Mushroom or Utricular Gland:** This gland is in the 7th abdominal segment and opens into the ejaculatory duct. It has three types of parts:
(a) **Seminal Vesicles:** These are small, round parts that hold sperm.
(b) **Short Central Tubules or Utricular Minores:** These are small tubes that make food for the sperm.
(c) **Long Peripheral Tubules of Utriculi Majores:** These are long, thin tubes that create the inner layer of the spermatophore.
4. **Ejaculatory Duct:** The male cockroach has a thin, glandular, and muscular ejaculatory duct. It is attached to the phallomere (a part of the external genitalia) on the underside. It opens outside through the male gonopore and releases the middle layer of the spermatophore.
5. **Phallic or Conglobate Gland:** This is a white, bag-like gland located under the ejaculatory duct. Its front part is wide, and its back part is narrow.
6. **Phallomeres of Gonapophyses:** The male opening (gonopore) has three uneven, hard, plate-like structures called phallomeres. They are described as:
(a) **Left Phallomere:** It has four parts: asperate lobe, titillator, acutolobus, and pseudopenis.
(b) **Right Phallomere:** It includes a hook, a serrated lobe, and two opposite lobes.
(c) **Ventral Phallomere:** It is a small, flat plate to which the ejaculatory duct is attached.

Female Reproductive Organs:
The female cockroach's reproductive system includes:
1. **Ovaries:** There is a pair of ovaries located in the 3rd to 6th abdominal segments. Each ovary has eight long, light yellow, tube-shaped ovarioles.
Each ovariole has five parts:
(i) Suspensory ligament
(ii) Gennarium
(iii) Vitellarium
(iv) Ovarium or Egg chamber
(v) Pedicle
The suspensory ligaments of all eight ovarioles are connected.
2. **Oviduct & Common Oviduct:** All eight ovarioles from one ovary open into an oviduct. Both oviducts join to form a common oviduct or a tube-like part (vagina) located in the 7th segment, which opens into a genital chamber.
3. **Gynatrium:** This is also known as the brood pouch. It is formed when the 8th and 9th sternites (plates on the underside of the abdomen) change shape. It has two parts:
(a) **Genital Chamber:** The front and smaller part.
(b) **Oothecal Chamber:** The back and larger part.
The gynatrium opens outside through the female gonopore (opening).
4. **Spermathecae:** There is a pair of spermathecae that are not equal in size, with the right one being smaller. They open through a common duct into the genital chamber, specifically at a small bump called the spermathecae papilla. They store sperm after mating.
5. **Colleterial Glands:** There is a pair of shiny, branched, and unequal colleterial glands. The left gland is larger and has more branches. Both glands open into the oothecal chamber through a common duct. One gland secretes dihydroxy phenol, and the other secretes a protein. These two substances combine to form a dark, hard covering.

**Reproduction Physiology:**
(i) **Formation of Spermatophore:** This happens in the male reproductive organs. It is a three-layered, bag-like structure full of sperm. The inner layer is made by the long peripheral tubules of the mushroom gland, the middle layer by the ejaculatory duct, and the outer layer by the phallic gland.
(ii) **Copulation (Mating):** Cockroaches mate at night, facing tail to tail. This process usually lasts about one hour and occurs during the breeding season, which runs from March to September. During mating, the male uses his phallomeres to open the female's gonopore and inserts a spermatophore into her genital chamber. The spermatophore attaches to the spermathecal papilla, and the sperm is stored in the spermathecae. This takes about 20 hours. The empty spermatophore is then pushed out and sometimes eaten by other cockroaches. During the breeding season, females release a scent (pheromone) that attracts males.
(iv) **Formation of Ootheca:** The female uses her ovipositors to push the fertilized eggs into the oothecal chamber in two rows of eight eggs each. Inside the oothecal chamber, secretions from the colleterial glands form a dark brown covering around the fertilized eggs. This structure is called the ootheca. It takes about 20 hours for an ootheca to form. The ootheca is 8-10 mm long and has one serrated (saw-like) end. A female cockroach can produce 20-40 oothecae in her lifetime. She carries the ootheca for a few days before depositing it in a dark, dry, and warm place. The cockroach eggs are centrally yolked (centrolecithal) and are covered by a hard, chitinous shell. Each egg also has a tiny opening called a micropyle.
In simple words: Cockroaches have separate male and female systems. Males have testes and glands that make and store sperm in a packet called a spermatophore. Females have ovaries that produce eggs and other glands that form a protective case called an ootheca for the eggs. Mating involves transferring the sperm packet, and then the female creates the ootheca where eggs develop.

🎯 Exam Tip: When describing complex biological systems, break down the answer into clear sections for male and female organs, and then explain the key processes like gamete formation and reproduction in a step-by-step manner. Diagrams, if requested, should be clearly labeled.