Free Practice Questions for Biology in General-studies

SSC CGL 23/08/21(Evening)

IMPORTANT FACTS

Ear

• The ears perform two sensory functions, hearing and maintenance of body balance. 
• Anatomically, the ear can be divided into three major sections called the outer ear, the middle ear and the inner ear.
• The smallest bone in the human body is found in the ear called stapes.
• The persistence of hearing is 1 / 10 second. 

• The outer ear consists of the pinna and external auditory meatus (canal). 
• The middle ear contains three ossicles called the malleus, incus, and stapes which are attached to one another in a chain-like fashion. 
• The inner ear has two main organs-The vestibular apparatus and the cochlea.

The Eustachian tubes equalize the air pressure on either side of the eardrum.

Important Points:

• The Eustachian tube connects the middle ear cavity with the nasopharynx.
• The Eustachian tube helps in equalizing the pressures on either side of the ear drum.
• The middle ear contains three ossicles called the malleus, incus, and stapes, which are attached to one another in a chain-like fashion.
• The malleus is attached to the tympanic membrane, and the stapes is attached to the oval window of the cochlea. 
• The ear ossicles increase the efficiency of the transmission of sound waves to the inner ear.

SSC CPO 9/12/19 (Evening)

IMPORTANT FACTS

• The eyeball is approximately spherical in shape with a diameter of about 2.3 cm. 

SSC-CGL 07/06/2019 (Morning)

IMPORTANT FACTS

Skin has three major layers-

• Epidermis - Epidermis is the outermost or epithelial layer of the skin. It is a waterproof protective layer that covers the body and serves as a barrier to infections.
• Dermis  - It is the fibrous connective tissue or supportive layer of the skin. It lies below the epidermis. It contains blood capillaries, nerve endings, sweat glands, hair follicles, and other structures. Dermis consists of collagen and elastin fibre. Collagen fibre has enormous tensile strength and provides the skin with strength and thickness. Elastin fibre provides elasticity and pliability to the skin.
• Hypodermis - It is a layer that lies below the dermis. It is also called ‘subcutaneous tissue’. It mainly consists of fat cells (adipocytes), nerves and blood vessels.

The pinna is the part of human ear collects sound from its surroundings.

Important Points:

• It sends sound to the eardrum via the auditory canal. 
• When sound strikes the eardrum, vibrations are sent to the middle ear's ossicles, malleus (hammer), incus (anvil), and stapes (stirrup).
• The inner ear has a structure known as the cochlea.
• Waves from the middle ear induce vibrations in the inner ear fluid, causing the cilia to vibrate and nerve signals to be sent to the brain.
• The ears have two sensory functions: hearing and maintaining body balance. 
• The ear is divided into three parts: the outer ear, the middle ear, and the inner ear.
• 

Skin is types of  Cutaneous membrane.

Important Points:

• The skin is the body's biggest organ. It protects the body by acting as a shield. 

  It shields the body from harm, such as damage, heat, radiation, chemicals, and microbes. 

  In the presence of sunlight, the skin produces an active form of vitamin D. 

  Melanocytes produce'melanin,' a black pigment that is responsible for skin colour. 

  The skin serves an excretory function by secreting perspiration and sebum, which eliminates a variety of toxic compounds produced by the intestine and liver's metabolic functions.

Skin has three major layers-

Snuff indicators indicate changes in the Smell.

Important Points:

• Tobacco is smoked, chewed, or snuffed. Snuff is a smokeless tobacco produced from finely powdered or shredded tobacco leaves.

  Tobacco contains a variety of chemical compounds, including nicotine, an alkaloid. 

  Nicotine stimulates the adrenal gland, causing it to release adrenaline and nor-adrenaline into the bloodstream, both of which boost blood pressure and heart rate. 

  Tobacco chewing is linked to an increased risk of oral cavity cancer.

Olfactory receptors are located in our nose.

Important Points:

• Receptors are typically found in our sense organs, such as the inner ear, nose, and tongue. 

  The nose contains mucus-coated receptors known as olfactory receptors, which are specialised for receiving the sensation of smell. 

Types of receptors-

Tears in the eyes are produced by Lacrimal glands.

Important Points:

• The lacrimal gland is found on the outer cornea of the eye, beneath the upper eyelid. 
• It is classified as an exocrine gland.  It continuously produces fluid that cleans and protects the eye's surface while also lubricating and moistening it. Tears are the common name for these lacrimal fluids.
• Tear gas is a chemical that irritates the mucous membranes of the eyes, resulting in stinging and tears.
  
  
  
  

The pigment that gives human skin, hair and eyes their colour is called melanin.

Important Points:

• Melanocytes are present in the epidermis's basal layer (the epidermis is the skin's outermost or epithelial layer).

  Melanin, a black pigment produced by these cells, is responsible for skin pigmentation. 

  Melanin is bundled into small parcels known as'melanosomes,' which are then delivered to keratinocytes. 

  Melanin shields the skin from UV radiation. Ageing causes an increase in melanin, which results in age spots.

Otoscope is used for visual examination of eardrum .

Important Points:

• An otoscope is a specialised hand-held equipment used by clinicians to inspect the ear canal and eardrum. 
• It can also be used to examine the body's nasal and throat passages. 

Option Explanation:

• An optometer is a device that records the course of light after it enters the eye. 
• A phonograph is a device designed to recreate sound recorded on a grooved disc. 
• A polygraph is also known as a lie detector gadget. It is often used to assess a person's physiological responses while answering a series of yes or no questions about a crime, occurrence, or any other sensitive purpose.

Rhodopsin , also called visual purple, located in the human eye.

Important Points:

• The retina is the inner layer of the eye, and it is made up of three layers of neural cells that run from inside to outside: ganglion cells, bipolar cells, and photoreceptor cells. 

  Photoreceptor cells are classified into two types: rods and cones. 

  These cells contain the light-sensitive proteins called the photopigments. 

  The rods include a purplish-red protein called rhodopsin, sometimes known as visual purple, which contains a Vitamin A derivative.

EYE-

In animal cells, lysosomes are the cell's 'garbage disposal.

Important Points:

• C. De Duve discovered lysosomes in 1955. 
• They are organelles with a single membrane.   
• Isolated lysosomal vesicles are extremely rich in nearly all types of hydrolytic enzymes (hydrolases - lipases, proteases, carbohydrases) that are maximally active at acidic pH.  
• Carbohydrates, proteins, lipids, and nucleic acids can all be digested by these enzymes. 
• Lysosomes are the cell's waste disposal system.  
• Lysosomes are known as "suicidal bags" because when a cell is injured, lysosomes might burst, allowing enzymes to devour their own cell. 

Mitochondria is called power house of the cell.

Important Points:

• Mitochondria is responsible the extracting energy from food through cellular respiration.
• The energy released in the form of ATP.
• Mitochondria is called energy currency of the cell.
• Mitochondria is a double membrane -bound semi autonomous organelle.

The sorting, tagging, packaging, and distribution of lipids and proteins in the human body take place in the Golgi apparatus.

Important Points:

• Its primary function is protein packaging and secretion. 
• It gets proteins from the Endoplasmic Reticulum. 
• It encapsulates it in membrane-bound vesicles, which are then transported to numerous locations, including lysosomes, the plasma membrane, and secretion. 
• They also help in lipid transport and the development of lysosomes. 

Ribosomes are the biological structures that are in charge of protein production.

Important Points:

• Ribosomes are responsible for the production of proteins from amino acids. 
• Ribosomes are also known as cell protein factories. 

Option Explanation: 

Lysosomes

• Lysosomes are the cell's waste disposal system. 
• C. De Duve discovered lysosomes in 1955. They are organelles with a single membrane.

Mitochondria

• The cell's powerhouse, synthesising ATP, the cell's energy currency. 
• Mitochondria are the organelles in charge of cellular respiration. 

Golgi apparatus 

• The Golgi apparatus is primarily responsible for packing materials for delivery to intracellular destinations or secretion outside the cell.

The largest cell in the human body is Ovum.

Important Points:

• It has a diameter of one millimetre.
• Sperm are the tiniest cells in the human body.
• All living organisms have a structural and functional unit called a cell. It is also known as a "life-building block."
• Mycoplasma, the smallest cells, are just 0.3 m long, whereas bacteria can be 3 to 5 m long.

The nucleus of a cell is surrounded by a jelly-like substance called cytoplsm.

Important Points:

• The endoplasmic reticulum, mitochondria, ribosomes, Golgi apparatus, centrosomes, lysosomes, vacuoles, and chloroplasts are all part of the cytoplasm. 
• The cytoplasm surrounding the nucleus is known as endoplasm, whereas that near the cell membrane is known as ectoplasm. 
• The nucleoplasm is the cytoplasm found within the nucleus.

Cells were first discovered by Robert Hooke in 1665. 

Important Points:

• He used a crude microscope to examine the cells in a cork slice. 

  For the first time, Leeuwenhoek (1674) observed free living cells in pond water using an improved microscope.   

Glycogen, poly-hydroxybutyrate granules, sulphur granules, and gas vesicles are all components of cytoplasm.

Important Points::

• The cell organelles, which comprise the endoplasmic reticulum, mitochondria, ribosomes, Golgi apparatus, centrosomes, lysosomes, vacuoles, and chloroplasts, are found in the cytoplasm. 
• The nucleoplasm is the cytoplasm found within the nucleus.
• Cytoplasm is a semi-fluid, jelly-like substance found within the cell membrane of all living cells. 
• It is one of the fundamental components of a cell and plays a crucial role in various cellular processes