RBSE Solutions Class 11 Biology Chapter 37 Frog

RBSE Class 11 Biology Chapter 37 Multiple Choice Objective Questions

 

Question 1. The class of frog is -
(a) Mammalia
(b) Amphibia
(c) Reptelia
(d) Pisces
Answer: (b) Amphibia
In simple words: Frogs belong to the amphibian class because they can live both on land and in water.

🎯 Exam Tip: Remember that amphibians are vertebrates that are typically cold-blooded and live on land but breed in water, like frogs and salamanders.

 

Question 2. Frog is
(a) Carnivorous
(b) Herbivorous
(c) Omnivorous
(d) Frugivorous
Answer: (a) Carnivorous
In simple words: Frogs eat other animals, mainly insects, which means they are meat-eaters.

🎯 Exam Tip: Knowing a frog's diet helps understand its position in the food chain and its ecological role.

 

Question 4. Respiration in frog is through the
(a) Skin
(b) Buccopharyngeal cavity
(c) Lungs
(d) All of the options
Answer: (d) All of the options
In simple words: Frogs can breathe using their skin, mouth lining (buccopharyngeal cavity), and lungs. They use different ways to breathe depending on where they are, like in water or on land.

🎯 Exam Tip: Frogs are unique in having multiple respiratory surfaces, allowing them to adapt to different environments; mention all three for full marks.

 

Question 5. Fertilization in frog is
(a) Internal
(b) External
(c) Sometime internal & sometime external
(d) Neither internal nor external
Answer: (b) External
In simple words: In frogs, fertilization happens outside the female's body, usually in water, where the male releases sperm over the eggs.

🎯 Exam Tip: External fertilization is common in aquatic animals like frogs, where water helps sperm reach the eggs easily.

 

Question 6. The larva of frog is
(a) Tadpole
(b) Nymph
(c) Tomaria
(d) Bipinnaria
Answer: (a) Tadpole
In simple words: The young form of a frog that hatches from an egg is called a tadpole. It looks very different from an adult frog.

🎯 Exam Tip: Remember that tadpoles live entirely in water and have gills for breathing, which disappear as they grow into adult frogs.

 

Question 7. The frog is
(a) Uricotelic
(b) Ammonotelic
(c) Ureotelic
(d) All of the options
Answer: (c) Ureotelic
In simple words: Adult frogs mainly get rid of nitrogen waste as urea. This means they are ureotelic.

🎯 Exam Tip: Recall that tadpoles are ammonotelic (excreting ammonia) while adult frogs are ureotelic. This change is an adaptation to their terrestrial life.

RBSE Class 11 Biology Chapter 37 Very Short Answer Questions

 

Question 1. The Indian frog is commonly called as ?
Answer: The Indian frog is commonly called the Indian bull frog.
In simple words: The common name for the Indian frog is the Indian bull frog.

🎯 Exam Tip: Knowing the common name helps identify specific species and can be useful for general biology knowledge.

 

Question 2. Write the zoological name of frog.
Answer: The zoological name of the frog is Rana tigrina.
In simple words: The scientific name for the common frog is Rana tigrina.

🎯 Exam Tip: Always write the genus name with a capital letter and the species name with a small letter, and underline or italicize both parts of the scientific name.

 

Question 3. Write the habitat of Rana tigrina.
Answer: Rana tigrina is an amphibious animal. It spends more time in water and less time on land.
In simple words: The frog Rana tigrina lives mostly in water but can also be found on land.

🎯 Exam Tip: Describe the amphibious nature of frogs, emphasizing their dual habitat preference (water and land).

 

Question 4. What is the food of frog ?
Answer: Frogs are carnivorous. They eat insects, small fishes, other small frogs, and similar small animals.
In simple words: Frogs eat insects, small fish, and even other small frogs.

🎯 Exam Tip: List a variety of prey items to show a comprehensive understanding of the frog's carnivorous diet.

 

Question 7. Which type of kidneys are found in frog?
Answer: Mesonephric kidneys are found in frogs.
In simple words: Frogs have mesonephric kidneys, which are a type of kidney found in many vertebrates.

🎯 Exam Tip: Accurately name the type of kidney (mesonephric) and briefly explain its evolutionary significance if possible.

 

Question 8. Give the site of embryonic development in frog.
Answer: The embryonic development in frogs takes place in water.
In simple words: Frog embryos grow in water.

🎯 Exam Tip: Mention that external fertilization in frogs means development also starts in their aquatic environment.

 

Question 9. Write the name of larva of frog.
Answer: The larva of a frog is called a tadpole.
In simple words: The baby frog, before it looks like an adult, is called a tadpole.

🎯 Exam Tip: Clearly state "tadpole" as the name of the larval stage, highlighting its distinct form from the adult frog.

 

Question 10. Through which structure the gametes (Ova & sperms) are released in frog?
Answer: Gametes (ova and sperms) are released through the cloacal aperture in frogs.
In simple words: Frogs release their eggs and sperm through an opening called the cloacal aperture.

🎯 Exam Tip: Identify the cloacal aperture as the common opening for reproductive, excretory, and digestive systems in frogs.

 

Question 11. How the croaking sound of frog is produced?
Answer: The croaking sound in frogs is produced by vocal sacs, which are usually present in male frogs.
In simple words: Male frogs make croaking sounds using special pouches called vocal sacs.

🎯 Exam Tip: Specify that vocal sacs are responsible for croaking and are primarily found in males, especially during breeding season.

 

Question 14. Write the main excretory substance of frog.
Answer: The main excretory substance of an adult frog is urea.
In simple words: Adult frogs mostly remove waste from their body as urea.

🎯 Exam Tip: Distinguish between the excretory products of tadpoles (ammonia) and adult frogs (urea) as an adaptation to their changing habitat.

RBSE Class 11 Biology Chapter 37 Short Answer Questions

 

Question 1. Give an account of the habit and habitat of frog.
Answer: Frogs are amphibious animals. This means they can live both on land and in water. They prefer to live in or near water bodies like ponds and ditches to keep their skin moist. Frogs are not poisonous or harmful. They are cold-blooded animals, so their body temperature changes with their surroundings. Frogs move around by jumping or leaping on the ground.
In simple words: Frogs live both on land and in water, mainly in wet places like ponds. They are not harmful and are cold-blooded, moving by jumping.

🎯 Exam Tip: Highlight the amphibious nature, preferred habitat (aquatic), cold-blooded characteristic (poikilothermic), and method of locomotion (jumping).

 

Question 2. Explain external features of frog.
Answer: The frog's body has a smooth, streamlined shape. Its front part is narrow, and the back part is wide and somewhat rounded. An adult frog is typically 12 to 18 cm long and 5 to 8 cm wide. Their body structure helps them move easily through water and on land.
In simple words: A frog's body is smooth and streamlined, narrow at the front and wide at the back. It is about 12-18 cm long and 5-8 cm wide.

🎯 Exam Tip: Focus on the streamlined body, narrow anterior and broad posterior ends, and provide an approximate size range for the frog.

 

Question 3. What is hibernation in frog?
Answer: Frogs are cold-blooded animals, so their body temperature changes with the environment. During winter, when it gets very cold, frogs stop eating and burrow into the soil. They usually go about 30 to 60 cm deep. Their body activities slow down a lot, and they breathe only through their moist skin. This state is called hibernation. When winter ends and spring begins, frogs become active again.
In simple words: Hibernation is when frogs bury themselves in the soil during cold winters, slowing down their body functions and breathing only through their skin until spring.

🎯 Exam Tip: Explain hibernation as an adaptation to cold weather, noting reduced metabolism, skin respiration, and burrowing behavior.

 

Question 4. Draw a labelled diagram of alimentary canal of frog.
Answer:
(Diagram showing the alimentary canal of frog, including parts like esophagus, stomach, duodenum, ileum, rectum, cloaca, liver, gallbladder, pancreas, spleen, etc. - refer to Fig. 37.2 on page 6 of the source document.)
In simple words: A labelled drawing of the frog's digestive organs shows how food travels through its body.

🎯 Exam Tip: Ensure all major parts of the alimentary canal and associated glands (liver, pancreas) are clearly labelled in your diagram.

 

Question 5. Give the role of digestive enzymes in frog.
Answer: Digestive enzymes in frogs help start the digestion process. Gastric juices contain hydrochloric acid (HCl) and protein-digesting enzymes. These enzymes break down food into smaller, absorbable particles.
In simple words: Digestive enzymes in frogs help break down food, with stomach juices containing acid and enzymes to digest proteins.

🎯 Exam Tip: Mention the specific role of enzymes in breaking down food and the presence of HCl for protein digestion.

 

Question 6. Which type of respiration is performed by frog inside and outside the water?
Answer: As an amphibious animal, the frog breathes both in water and in the air. This means it can perform both aquatic (in water) and aerial (in air) respiration. It uses its skin, lungs, and buccopharyngeal cavity for breathing.
In simple words: Frogs breathe both in water and in the air. They use their skin, lungs, and mouth lining to do this.

🎯 Exam Tip: Emphasize that frogs are adaptable respirators, using different organs (skin, lungs, buccal cavity) depending on whether they are in water or on land.

 

Question 8. Write the process of blood circulation in frog.
Answer: The blood circulation in frogs involves blood, the heart, and blood vessels.
(A) Blood: Frog blood is red. It is made up of plasma (60%) and blood corpuscles (40%). The blood corpuscles are of three main types:
1. Red blood corpuscles: These cells contain hemoglobin, which carries oxygen.
2. White blood corpuscles: These cells help fight infections.
3. Thrombocytes: These cells help in blood clotting.
(B) Heart: The frog's heart is shaped like a cone and is dark red. It is a muscular organ located in the front part of the body cavity, near the front limbs. The heart has three chambers: two upper chambers called auricles (left and right) and one lower chamber called a ventricle. Both auricles open into the ventricle through a common opening. There is also a triangular sinus venosus that collects blood from two large veins (precavals) and one large vein (post caval) before it enters the right auricle. The left auricle receives oxygen-rich blood from the lungs through pulmonary veins.
(C) Blood Vessels: The blood vessel system includes arteries (which carry blood away from the heart) and veins (which carry blood toward the heart). Frogs have two special types of portal systems:
1. Hepatic portal system: This system involves blood flow to the liver.
2. Renal portal system: This system involves blood flow to the kidneys.
In simple words: Frog circulation uses a three-chambered heart to pump blood, which contains plasma and red, white, and clotting cells. Blood travels through arteries and veins, with special systems for the liver and kidneys.

🎯 Exam Tip: Describe the composition of blood, the three-chambered heart structure, and the presence of both hepatic and renal portal systems in the frog's circulatory system.

 

Question 9. Describe the structure of brain of frog.
Answer:
(Diagram showing the dorsal and ventral views of the frog's brain, including parts like cerebral hemisphere, pineal body, diencephalon, optic lobe, cerebellum, medulla, corpus striatum, optic chiasma, infundibulum, pituitary, and spinal cord - refer to Fig. 37.5 A on page 9 and Fig. 37.5 B on page 10 of the source document.)
The frog's nervous system includes a central nervous system (brain and spinal cord) and a peripheral nervous system (ganglionated chains). Frogs have 10 pairs of cranial nerves and 9 pairs of spinal nerves.
The brain is an elongated white structure protected by the skull bones (cranium). It is divided into three main parts:
1. Forebrain: This part includes a pair of olfactory lobes, a pair of cerebral hemispheres (also called cerebrum), and one diencephalon.
2. Midbrain: This part consists of a pair of optic lobes, which are hollow and have cavities called optocoel.
3. Hindbrain: This part is made up of one cerebellum and one medulla oblongata.
In simple words: The frog's brain is long and white, protected by the skull. It has a forebrain (for smell and thinking), a midbrain (for vision), and a hindbrain (for balance and basic body functions).

🎯 Exam Tip: For the brain's structure, identify the three main divisions (forebrain, midbrain, hindbrain) and mention key components within each, along with the protective cranium.

 

Question 10. Which types of sense organs are found in frog.
Answer: Frogs have several sense organs:
1. Cutaneous receptors: These are different types of sense organs found in the skin, below the outer layer. They detect touch, cold, heat, light, and pain.
2. Gustoreceptors: These are taste receptors, found in small numbers on the tongue and in the roof of the mouth cavity. They help the frog taste things.
3. Olfactoreceptors: Located in the nostrils, these receptors help the frog smell.
4. Eyes: Frogs have one pair of movable eyes, located on the sides of their head. The eyes are large and round. The eye wall has three layers: sclerotic, choroid, and retina. The front part of the eye is clear (cornea), and the image forms on the retina.
In simple words: Frogs have sense organs for touch, cold, heat, light, pain (in skin), taste (on tongue), smell (in nostrils), and sight (large, movable eyes with a retina).

🎯 Exam Tip: List the different types of sense organs (cutaneous, gustatory, olfactory, visual) and briefly describe their location and function in the frog.

 

Question 11. Differentiate male and female frog.
Answer: Frogs show sexual dimorphism, meaning male and female frogs have clear differences:
• Male frogs are usually darker in color than female frogs.
• Male frogs are generally bigger in size compared to females.
• During the breeding season, male frogs develop a pair of vocal sacs that become very noticeable. These sacs help them make croaking sounds.
• The first finger on the male frog's hand develops a special pad called a copulatory or amplexury pad. This pad also becomes prominent during the breeding season and is used to hold the female during mating.
In simple words: Male frogs are darker, bigger, have vocal sacs for croaking, and a special thumb pad for mating, unlike female frogs.

🎯 Exam Tip: Focus on the four key distinguishing features: color, size, vocal sacs, and the copulatory pad, and mention their prominence during the breeding season.

 

Question 12. Write the name of endocrine glands and their hormones in frog.
Answer: The endocrine glands in frogs and the hormones they produce are listed below:

In simple words: Frogs have glands like the hypothalamus, pituitary, thyroid, adrenal, testes, ovaries, and pancreas, each making specific hormones such as oxytocin, FSH, thyroxine, corticosterone, androgen, estrogen, insulin, and glucagon.

🎯 Exam Tip: For each gland, correctly list the major hormones it produces, as this demonstrates knowledge of the frog's endocrine system.

 

Question 13. Draw a labelled diagram of male reproductive system of frog.
Answer:
(Diagram showing the male reproductive system of frog, including parts like testis, adrenal gland, Bidder's canal, seminal vesicle, ureter, urinary bladder, cloaca, vasa efferentia, and rectum - refer to Fig. 37.6 on page 12 of the source document.)
In simple words: A drawing of the male frog's reproductive parts, with all labels, shows how it reproduces.

🎯 Exam Tip: Include all essential organs like testes, vasa efferentia, Bidder's canal, seminal vesicles, ureters, and cloaca, ensuring clear and accurate labelling.

 

Question 14. Draw a labelled diagram of female reproductive system of frog.
Answer:
(Diagram showing the female reproductive system of frog, including parts like ovary, oviducts, ovisac, ureter, urinary bladder, cloacal aperture, and fat bodies - refer to Fig. 37.7 on page 13 of the source document.)
In simple words: A drawing of the female frog's reproductive parts, with all labels, shows how it reproduces.

🎯 Exam Tip: Label key structures such as ovaries, oviducts, ovisacs, and the cloacal aperture to illustrate the female reproductive anatomy accurately.

 

Question 15. What is the role of HCI in the process of digestion.
Answer: Hydrochloric acid (HCl) in the frog's stomach makes the food very acidic. This acidic environment helps kill germs and aids in the digestion of food, especially proteins.
In simple words: HCl in the frog's stomach makes food acidic, which helps kill germs and digest food.

🎯 Exam Tip: State both primary roles of HCl: creating an acidic medium for enzyme activity and acting as a germicidal agent.

RBSE Class 11 Biology Chapter 37 Essay Type Questions

 

Question 1. Describe the morphology of the frog.
Answer:
Shape and Size: The body of a frog is smooth and streamlined, designed for easy movement. Its front part (anterior end) is narrow, while the back part (posterior end) is wide and somewhat rounded. Typically, an adult frog is about 12 to 18 cm long and 5 to 8 cm wide.
Body Division: A frog's body is divided into a head and a trunk, with no visible neck. This lack of a neck helps reduce friction when it swims.
1. Head: The head is triangular and narrow at the front. It has a broad, blunt snout and a wide mouth. There are external nostrils on the head. Frogs have two large, prominent eyes on the upper sides of the head. Each eye has movable upper and lower eyelids. Additionally, a third, thin, and transparent eyelid called the nictitating membrane protects the eye underwater. Below the eyes, there are dark, round patches called tympanum, which are the eardrums.
2. Trunk: The trunk is wide and somewhat round, directly connected to the head. It has two front limbs (forelimbs) and two back limbs (hindlimbs). The forelimbs are shorter and have four fingers (tetradactylus), lacking a thumb. The hindlimbs are longer, bent like a "Z," webbed between the five toes (pentadactylus). During the breeding season, the first finger of the male's forelimb develops a copulatory pad, used to hold the female during mating. The fingers and toes of both limbs do not have claws.
Frog also shows sexual dimorphism, meaning male and female frogs have clear differences:
• Male frogs are usually darker in color than female frogs.
• Male frogs are generally bigger in size compared to females.
• During the breeding season, male frogs develop a pair of vocal sacs that become very noticeable. These sacs help them make croaking sounds.
• The first finger on the male frog's hand develops a special pad called a copulatory or amplexury pad. This pad also becomes prominent during the breeding season and is used to hold the female during mating.
In simple words: A frog's body is streamlined with a narrow head and wide trunk, without a neck. It has large eyes with a third eyelid, and eardrums called tympanum. It has short front limbs with four fingers and long, webbed back limbs with five toes. Males are usually darker and bigger, and have vocal sacs and a special pad on their thumb for mating.

🎯 Exam Tip: When describing morphology, categorize features clearly (e.g., shape/size, body divisions) and include details about adaptations like webbed feet or the nictitating membrane.

 

Question 2. Describe the physiology of digestion in frog.
Answer:
Food and Digestion: Frogs are carnivorous, meaning they eat other animals. Their diet includes insects, worms, small fishes, and even other small frogs. They catch their prey using their slimy tongue, which can dart out quickly, and then swallow the prey whole.
Digestion takes place in various parts of their digestive system:

In simple words: Frogs eat insects and small animals whole. Their digestive system uses gastric juice (with acid and protein enzymes), bile (to make food alkaline and break down fats), pancreatic juice (to digest proteins, starches, and fats), and intestinal juice (to break down sugars and fats further). Hormones also help control these digestive juices.

🎯 Exam Tip: Detail the specific enzymes and their functions in each part of the digestive tract, and also mention the role of bile in fat emulsification and the hormones that regulate digestion.

RBSE Class 11 Biology Chapter 37 Essay Type Questions

 

Question 3. Describe the nervous system of frog.
Answer: The frog's nervous system includes two main parts. First, the central nervous system, which contains the brain and spinal cord. Second, the peripheral nervous system, which has a pair of nerve chains with ganglia located on both sides of the vertebral column. The frog has 10 pairs of cranial nerves and 9 pairs of spinal nerves.
The brain is a long, white structure encased in the skull bones (cranium). It is divided into three sections: the forebrain, midbrain, and hindbrain. The forebrain includes two olfactory lobes, two cerebral hemispheres (called cerebrum), and one diencephalon. The midbrain has two optic lobes, which are hollow and contain cavities called optocoel. The hindbrain is made up of one cerebellum and one medulla oblongata.
In simple words: The frog's brain and nerves control its body. It has a central brain and spinal cord, plus other nerves. Its brain is divided into front, middle, and back parts, each doing different jobs.

🎯 Exam Tip: When describing organ systems, always mention the main divisions, the components of each division, and a brief description of key structures, like how the brain is divided.

 

 

Question 4. Describe the reproductive system and embryonic development in frog.
Answer: Frogs are unisexual, meaning male and female reproductive organs are found in separate animals. They show distinct sexual dimorphism, which means males and females have noticeable differences.

Male Reproductive System:
The male reproductive system includes:
(i) Testes: Frogs have a pair of testes, which are oval and yellow. These are attached to the front-outer side of the kidneys. Each testis contains many seminiferous tubules, which are the main structural and functional units. The testes produce male gametes, called sperms.
In simple words: Frogs have separate males and females. The male frog's reproductive system has oval, yellow testes near the kidneys that make sperm.

🎯 Exam Tip: When describing a system, always specify if the animal is unisexual or bisexual, and then detail the organs involved for each sex, noting their location and primary function.

 

Answer: (Continued from previous page)

Female Reproductive System:
In female frogs, the kidneys are similar to those in males but are not involved in reproduction. The female reproductive system consists of:

• Ovaries: There is a pair of large, branched, yellow ovaries that are superficially attached to the kidneys. Ova are formed through oogenesis and are released into the body cavity.
• Oviducts: There is a pair of long, coiled, and glandular oviducts, also called Mullerian ducts. The front end of the oviduct is funnel-shaped (ostium). The middle part is thin and coiled. The back part forms an ovisac, which temporarily stores the ova. Both ovisacs open separately into the cloaca.

Physiology of Reproduction:
Frogs are seasonal breeders and reproduce during the rainy season. A mature female lays about 2500 to 3000 eggs in a spawn. These eggs are mesolecithal and are about 1 to 2 mm in size.
In simple words: Female frogs have kidneys like males, but they also have ovaries that make eggs and oviducts that carry them. They lay many eggs during the rainy season.

🎯 Exam Tip: When detailing the female reproductive system, focus on the structures involved in egg production and transport, and explain the key aspects of their breeding cycle, such as when and how eggs are laid.

 

Answer: (Continued from previous page)
Fertilization in frogs happens externally, and their development is indirect. The larva is known as a tadpole larva. This tadpole larva undergoes metamorphosis to transform into a young frog.
In simple words: Frog eggs are fertilized outside the body. The babies, called tadpoles, grow and change into small frogs.

🎯 Exam Tip: For embryonic development, clearly state the type of fertilization (external/internal), type of development (direct/indirect), and the larval stages if present, along with the process of metamorphosis.

 

Question 5. Describe the blood vascular system in frog.
Answer: The frog's blood vascular system includes blood, the heart, and blood vessels.

(A) Blood:
Blood is red and consists of 60% plasma and 40% blood corpuscles. There are three types of blood corpuscles:
1. Red blood corpuscles: These contain hemoglobin.
2. White blood corpuscles
3. Thrombocytes.
In simple words: The frog's body has blood that moves around. The blood is red and has plasma and small cells like red blood cells (with hemoglobin), white blood cells, and thrombocytes.

🎯 Exam Tip: When describing blood composition, always mention the percentage of plasma and corpuscles and list the different types of corpuscles with their key characteristic (e.g., hemoglobin for RBCs).

 

Answer: (Continued from previous page)
There is a triangular sinus venosus that receives blood from two precavals and one postcaval vein. This sinus venosus opens into the right auricle. On the right ventral side of the heart, there is a truncus arteriosus, into which the ventricle opens. The left auricle receives blood from the pulmonary veins.

(C) Blood Vessels:
The blood vessels include both the arterial system (various types of arteries) and the venous system (various types of veins). The veins form two types of portal systems:
1. Hepatic portal system - Found in the liver.
2. Renal portal system - Found in the kidneys.
In simple words: The heart has a special part called the sinus venosus that collects blood. Then, this blood goes into the heart chambers. The body has arteries that carry blood away and veins that bring blood back, forming special systems in the liver and kidneys.

🎯 Exam Tip: For the circulatory system, make sure to detail the chambers of the heart, the major vessels connected to them, and the unique portal systems if present, along with their locations.