1. In what form excess of glucose is stored in human body ?

In what form excess of glucose is stored in human body ?

Fructose
Glycogen
Glucose
Starch
This question was previously asked in
UPSC CAPF – 2024
The correct option is B. In the human body, excess glucose is stored primarily in the liver and muscles in the form of glycogen.
– Glycogen is a complex polysaccharide, a branched polymer of glucose.
– This process of glucose storage as glycogen is called glycogenesis.
– Glycogen serves as a readily available energy reserve.
Fructose is a different type of sugar. Glucose is the circulating form of sugar in the blood, used for immediate energy. Starch is the primary storage form of glucose in plants, not in animals or humans.

2. Lactic acid is formed in the muscles during exercise or running. It is

Lactic acid is formed in the muscles during exercise or running. It is formed :

to give extra energy from fat.
to give extra oxygen from lungs.
to give extra energy from glucose.
to give extra energy from vitamins.
This question was previously asked in
UPSC CAPF – 2023
During intense exercise, when oxygen supply to muscles may not meet the demand for aerobic respiration, muscle cells can generate ATP (energy) through anaerobic glycolysis. Glucose is broken down to pyruvate, which is then converted to lactate (lactic acid) in the absence of sufficient oxygen. This process regenerates NAD+, allowing glycolysis to continue and produce a small amount of ATP from glucose, providing extra energy when aerobic pathways are limited.
Lactic acid is produced during anaerobic respiration in muscles, which occurs when oxygen is insufficient for aerobic metabolism. This process allows glycolysis to continue, yielding ATP from glucose for energy.
Anaerobic respiration primarily uses glucose, not fat, as the substrate. Lactic acid formation happens due to a lack of sufficient oxygen supply, not to provide extra oxygen. Vitamins are not used as a direct energy source.

3. In vertebrates, smooth endoplasmic reticulum in cells of which organ p

In vertebrates, smooth endoplasmic reticulum in cells of which organ plays a crucial role in detoxification of toxic compounds ?

Spleen
Intestine
Kidney
Liver
This question was previously asked in
UPSC CAPF – 2023
The smooth endoplasmic reticulum (SER) is involved in various metabolic processes, including lipid synthesis, steroid hormone production, and importantly, detoxification of drugs, poisons, and metabolic waste products. In vertebrates, the liver is the primary organ for detoxification, and its cells (hepatocytes) are particularly rich in SER, which contains enzymes like cytochrome P450 that metabolize these toxic compounds, often making them more soluble for excretion.
– Smooth endoplasmic reticulum is involved in detoxification.
– The liver is the main detoxification organ in vertebrates.
– Liver cells (hepatocytes) contain abundant smooth endoplasmic reticulum.
While other organs might have some detoxification capabilities or be involved in elimination (like kidneys), the liver’s role in metabolic detoxification via enzymes located in the SER is crucial and most prominent. The spleen is mainly involved in filtering blood, immune responses, and red blood cell turnover. The intestine is involved in digestion and absorption, and while it has some metabolic activity, its primary role is not systemic detoxification. The kidneys are primarily involved in filtering blood and excreting waste in urine.

4. Which one of the following is not a connective tissue?

Which one of the following is not a connective tissue?

Ligament
Tendon
Smooth muscle
Cartilage
This question was previously asked in
UPSC CAPF – 2021
The correct answer is C) Smooth muscle.
Connective tissues are tissues that support, connect, or separate different types of tissues and organs in the body. Ligaments connect bone to bone, tendons connect muscle to bone, and cartilage is a flexible connective tissue found in joints, ear, nose, etc. All three (Ligament, Tendon, Cartilage) are types of connective tissue. Smooth muscle, however, is a type of muscle tissue, specialized for contraction, and is distinct from connective tissue.
There are four main types of tissues in animals: epithelial tissue, connective tissue, muscle tissue, and nervous tissue. Connective tissue includes bone, blood, adipose tissue, and fibrous connective tissue (like ligaments and tendons) in addition to cartilage. Muscle tissue is classified into skeletal muscle, smooth muscle, and cardiac muscle.

5. If a healthy freshwater fish is placed in saltwater, the fish

If a healthy freshwater fish is placed in saltwater, the fish

becomes dehydrated and dies
becomes bloated and dies
suffers from microbial infection and dies
experiences no problem
This question was previously asked in
UPSC CAPF – 2011
Freshwater fish live in a hypotonic environment, meaning the concentration of solutes in the surrounding water is lower than in their body fluids. Water constantly enters their body by osmosis, and salts are lost. Freshwater fish deal with this by drinking very little water, actively absorbing salts through their gills, and excreting large amounts of dilute urine.
When a healthy freshwater fish is placed in saltwater, it moves into a hypertonic environment, where the solute concentration outside is much higher than inside its body. This causes water to move *out* of the fish’s body into the surrounding saltwater by osmosis. This leads to rapid dehydration of the fish’s tissues and organs. The fish cannot osmoregulate effectively in this environment and will become dehydrated and eventually die.
Osmosis causes water to move from an area of lower solute concentration to an area of higher solute concentration. Freshwater fish are adapted to prevent water intake and conserve salts; saltwater fish are adapted to conserve water and excrete excess salts. Moving a fish from its native environment to one with significantly different salinity disrupts its osmoregulatory balance.
Marine fish, in contrast, live in a hypertonic environment. They tend to lose water and gain salts. They deal with this by drinking large amounts of saltwater, actively excreting excess salts through their gills and kidneys, and producing small amounts of concentrated urine. Euryhaline fish, such as salmon, are adapted to survive in both freshwater and saltwater environments by changing their osmoregulatory mechanisms.

6. A camel adapts easily in a desert due to:

A camel adapts easily in a desert due to:

hump with stored food as fats
water cells in stomach to store metabolic water
nucleated Red Blood Cells
hair growth near eyes and nostrils
This question was previously asked in
UPSC CAPF – 2011
A camel adapts easily in a desert due to several physiological and structural adaptations. Let’s evaluate the options:
A) hump with stored food as fats: Correct. The hump stores large amounts of fat. Metabolizing this fat provides energy and also produces metabolic water. This fat storage also helps insulate the body, reducing heat absorption.
B) water cells in stomach to store metabolic water: Incorrect. Camels do not store water in special stomach cells in this manner. While they are efficient at conserving water and can tolerate significant dehydration, their water is stored mainly in the bloodstream and tissues. Metabolic water is produced from the metabolism of fats (as in A), not stored directly in “water cells” in the stomach.
C) nucleated Red Blood Cells: Correct. Camel RBCs are oval and nucleated, which helps them flow even when blood is thickened during dehydration. They can also swell significantly when the camel rehydrates without bursting, unlike typical mammalian RBCs. This is a crucial adaptation for managing hydration.
D) hair growth near eyes and nostrils: Correct. Long eyelashes and hair in the nostrils are effective physical barriers that protect the eyes and respiratory passages from sandstorms.
Given that multiple options (A, C, D) describe actual adaptations, and the question asks for “a camel adapts easily in a desert due to”, implying selecting a correct reason from the list, and considering it’s an MCQ with a single correct answer format, there might be an intended “primary” adaptation or the most popularly known one. Option B is factually incorrect. Options A, C, and D are correct adaptations. However, if forced to choose one from A, C, D as the single best answer representing overall adaptation ‘easily’, it’s challenging. But since the provided answer is A, we mark A as correct. It’s possible the question intends to highlight the energy/water reserve aspect (A).
Camels possess several key adaptations for desert life, including fat storage in the hump for energy and metabolic water, tolerance to dehydration facilitated by specialized RBCs, efficient water conservation, and physical protection from sand and heat. Option B is factually incorrect.
Other camel adaptations include thick padded feet for walking on sand, tough mouth lining for eating thorny plants, and the ability to regulate body temperature over a wide range.

7. In which part or organ of human body cartilage is NOT found ?

In which part or organ of human body cartilage is NOT found ?

Nose
Trachea
Bronchiole
Knee joint
This question was previously asked in
UPSC NDA-2 – 2024
Cartilage is a flexible connective tissue found in various parts of the body. While present in the nose, trachea, and knee joints, it is absent in the smaller airways called bronchioles.
The respiratory tract contains cartilage in the trachea and bronchi to maintain their structure and prevent collapse. As the airways branch into smaller bronchioles (less than 1 mm in diameter), the cartilage rings disappear, and the walls become primarily smooth muscle and elastic tissue, which allows for regulation of airflow through bronchoconstriction and bronchodilation.
Cartilage provides support and flexibility. Different types of cartilage exist, such as hyaline cartilage (found in the trachea and joints), elastic cartilage (found in the ear and epiglottis), and fibrocartilage (found in intervertebral discs and menisci of the knee). The absence of cartilage in bronchioles is a key anatomical feature distinguishing them from larger airways.

8. The part of the human ear that converts the pressure variations associ

The part of the human ear that converts the pressure variations associated with audible sound waves to electrical signals is

auditory nerve
cochlea
eardrum
eustachian tube
This question was previously asked in
UPSC NDA-2 – 2022
The cochlea is the part of the human ear responsible for converting the mechanical vibrations caused by sound waves into electrical signals.
– Sound waves enter the ear canal and cause the eardrum (tympanic membrane) to vibrate.
– These vibrations are transmitted through the middle ear ossicles (malleus, incus, and stapes) to the oval window.
– The oval window’s movement creates pressure variations in the fluid within the cochlea, which is a spiral-shaped structure in the inner ear.
– The cochlea contains the organ of Corti, which houses tiny hair cells. These hair cells are mechanoreceptors that are stimulated by the fluid movements.
– When stimulated, the hair cells generate electrical signals, which are then transmitted to the brain via the auditory nerve.
The auditory nerve transmits the electrical signals from the cochlea to the brain for processing. The eardrum is a membrane that vibrates in response to sound waves, transmitting these vibrations to the middle ear bones. The Eustachian tube connects the middle ear to the nasopharynx and helps equalize pressure.

9. Human eye can see objects at different distances with contrasting illu

Human eye can see objects at different distances with contrasting illuminations. This is due to

far-sightedness
near-sightedness
far-sightedness and near-sightedness
accommodation of eye
This question was previously asked in
UPSC NDA-2 – 2022
Human eye can see objects at different distances with contrasting illuminations due to the accommodation of eye.
The ability of the eye to adjust its focal length to see objects clearly at different distances is called accommodation. This is achieved by changing the shape of the lens. While “contrasting illuminations” involves other mechanisms like pupil size adjustment (controlled by the iris) and adaptation of photoreceptor cells, “accommodation of eye” is the term that best describes the eye’s overall ability to adjust to different viewing conditions presented in the question, especially the “different distances” aspect, and is the only adaptive mechanism listed among the options.
Far-sightedness and near-sightedness are refractive errors, not adaptive mechanisms. Accommodation primarily refers to focusing for distance, but in a broader sense, the eye’s overall ability to adapt to changing viewing conditions (distance and light) is a form of accommodation or adaptation. Given the options, “accommodation of eye” is the most appropriate answer describing the dynamic adjustment process.

10. Cornea in human eye

Cornea in human eye

is a light sensitive screen.
is a muscular diaphragm.
contains blood vessels.
is composed of proteins and cells.
This question was previously asked in
UPSC NDA-2 – 2021
The correct answer is D) is composed of proteins and cells.
The cornea is the transparent outer layer at the front of the eye. It is composed of highly organized layers of collagen proteins and specialized cells, which contribute to its transparency and structural integrity.
The retina (A) is the light-sensitive screen at the back of the eye. The iris (B) is a muscular diaphragm that controls the size of the pupil. The cornea (C) is avascular, meaning it does not contain blood vessels, which is crucial for its transparency.