Mix Examples - Life Processes Questions in English

(A) The hormone released into the blood when sugar levels rise is $Insulin$.
The organ that produces this hormone is the $Pancreas$.
$Insulin$ helps in reducing the blood sugar level by facilitating the uptake of glucose by cells.
The digestive enzymes secreted by the $Pancreas$ are:
$1$. $Pancreatic \ amylase$: Breaks down carbohydrates into simpler sugars.
$2$. $Trypsin$: Digests proteins into peptides.
$3$. $Lipase$: Breaks down emulsified fats into fatty acids and glycerol.
$(b)$ In multicellular organisms,electrical impulses (nerve impulses) can only reach a limited number of cells connected by nervous tissue. Furthermore,cells cannot continuously create and transmit electrical impulses. Therefore,to ensure that all cells in the body receive necessary signals,multicellular organisms use chemical communication (hormones),which can travel through the blood to reach every cell in the body.

(A) $(a) (i)$ Herbivores,which consume grass,possess a longer small intestine to facilitate the digestion of cellulose. Cellulose is a complex carbohydrate that requires more time to break down,necessitating a longer transit time within the digestive tract.
$(a) (ii)$ Carnivores,which consume meat,have a shorter small intestine because meat is protein-rich and relatively easy to digest,requiring less time for nutrient absorption.
$(b) (i)$ Within the lungs,the trachea branches into smaller tubes called bronchi and bronchioles,which terminate in numerous balloon-like structures known as alveoli. These alveoli are surrounded by an extensive network of blood capillaries,providing a massive surface area for the efficient diffusion of gases.
$(b) (ii)$ The concentration of dissolved oxygen in water is significantly lower than the concentration of oxygen in the atmosphere. Consequently,aquatic organisms,such as fish,must pump water through their gills at a much higher rate to extract sufficient oxygen for their metabolic needs.

(N/A) Bile makes the acidic food coming from the stomach alkaline,which enables pancreatic enzymes to act. Bile salts emulsify large fat globules into smaller ones,which increases the surface area for enzyme action,thereby increasing the efficiency of digestion.
$(b)$ The products formed after complete digestion are:
Carbohydrates: Glucose
Proteins: Amino acids
Fats: Fatty acids and glycerol

(N/A) The sectional view of the human heart is shown in the provided figure.
$(b)$ Double circulation of blood is necessary in human beings for the following reasons:
$(i)$ To separate deoxygenated blood from oxygenated blood,preventing their mixing.
$(ii)$ To meet the high energy and oxygen demands of the body,as humans are warm-blooded organisms.
$(iii)$ To maintain a constant body temperature (homeothermy) by ensuring efficient oxygen supply to all tissues.

(N/A) The structure of a nephron is shown in the figure. The key parts are the Glomerulus (a cluster of capillaries),Bowman's capsule (a cup-shaped structure surrounding the glomerulus),the Renal artery (which brings blood to the nephron),and the Collecting duct (which collects urine from various nephrons).
$(b)$ When blood is filtered through the glomerulus,substances like glucose,amino acids,salts,and water enter the Bowman's capsule as part of the filtrate. As this filtrate moves through the tubular part of the nephron,useful substances like glucose are selectively reabsorbed back into the blood capillaries surrounding the tubule.

(N/A) The human urinary system consists of a pair of kidneys,a pair of ureters,a urinary bladder,and a urethra. (Refer to the provided diagram for labeling).
$(b)$ The two major components of normal human urine are:
$1.$ Water (which constitutes about $95\%$ of urine).
$2.$ Nitrogenous waste products,primarily urea (which constitutes about $2\%$ of urine),along with other salts and minerals.

(N/A) Refer to the provided diagram of the human alimentary canal.
$(b)$ Bile does not contain any digestive enzymes,yet it is essential for digestion due to the following reasons:
$(i)$ It makes the acidic food coming from the stomach alkaline,which is necessary for the action of pancreatic enzymes.
$(ii)$ It contains bile salts that help in the emulsification of fats,breaking down large fat globules into smaller ones to increase the efficiency of enzyme action.

(N/A) The diagram of the human excretory system is provided in the image.
$(b)$ Two vital functions of the kidneys are:
$(i)$ They maintain the $pH$ and salt concentration of the body constant,and also regulate the water balance.
$(ii)$ They help in the removal of nitrogenous waste products (like urea) that are harmful to the human body.

(N/A) Enzymes are biological catalysts that accelerate the rate of biochemical reactions within living organisms. They are primarily proteinaceous in nature.
In humans,the enzyme $Lipase$ is responsible for the digestion of fats (lipids) into fatty acids and glycerol.

(N/A) Transpiration is the loss of water in the form of water vapor from the aerial parts of the plant,primarily the leaves.
Significance of transpiration:
$(i)$ Cooling effect: Transpiration helps in cooling the plant surface,especially during hot weather,as the evaporation of water consumes heat energy.
$(ii)$ Transport of water and minerals: It creates a transpiration pull (a suction force) that helps in the upward movement of water and dissolved minerals from the roots to the leaves.
$(iii)$ Distribution of water: It ensures the continuous supply and proper distribution of water and essential nutrients throughout the plant body.
$(iv)$ Maintenance of turgidity: It helps in maintaining the turgidity of cells,which is essential for the structural support and growth of the plant.

(N/A) The possible disease the patient is suffering from is $Diabetes$ $Mellitus$.
$Insulin$ is a hormone secreted by the $\beta$ cells of the $pancreas$ that regulates blood glucose levels in the body.
When the $pancreas$ fails to produce sufficient $insulin$, or when the body cells do not respond effectively to $insulin$, blood sugar levels rise significantly.
High blood sugar levels lead to $diabetes$, which is why doctors advise patients to reduce sugar intake to manage and control their blood glucose levels.

(N/A) Functions of bile juice:
$(i)$ It emulsifies large fat globules into smaller ones,thereby increasing the surface area for enzyme action.
$(ii)$ It makes the acidic food coming from the stomach alkaline,which is essential for the activity of pancreatic enzymes.
$(b)$ Differences between pepsin and trypsin:
$1.$ Pepsin: It acts on proteins in an acidic medium in the stomach.
$2.$ Trypsin: It acts on proteins in an alkaline medium in the small intestine.

(N/A) In tissues,oxygen is consumed for metabolic activities,leading to a low concentration of oxygen and a high concentration of carbon dioxide. Conversely,blood arriving from the lungs has a high concentration of oxygen and a low concentration of carbon dioxide. Due to this partial pressure gradient,gases move between the blood and tissues via the process of simple diffusion.
$(b)$ The respiratory pigment in humans is Haemoglobin. It is found inside the Red Blood Corpuscles $(RBCs)$.

(N/A) Liver: Produces bile juice. Bile salts present in it emulsify large fat globules into smaller ones,facilitating digestion. It also stores excess glucose in the form of glycogen.
Gall bladder: Stores and concentrates the bile juice produced by the liver until it is needed for digestion in the small intestine.
Villi: These are numerous finger-like projections present on the inner lining of the small intestine. They increase the surface area for the absorption of digested food. The villi are richly supplied with blood vessels that transport the absorbed nutrients to every cell of the body.

(N/A) One nitrogenous waste present in urine is $Urea$.
The basic filtration unit of the kidney is called a $Nephron$.
The amount of urine produced is regulated by the quantity of excess water present in the body and the amount of dissolved nitrogenous wastes that need to be excreted. Additionally,hormones like $ADH$ (Antidiuretic Hormone) play a crucial role in reabsorbing water from the kidney tubules based on the body's hydration status.

(N/A) Autotrophic organisms fulfill their energy requirements through a process called $Photosynthesis$.
In this process, autotrophs take in external substances like $CO_2$ and $H_2O$ and convert them into energy-rich carbohydrates in the presence of sunlight and chlorophyll.
The chemical reaction is: $6CO_2 + 12H_2O \xrightarrow[Chlorophyll]{Sunlight} C_6H_{12}O_6 + 6O_2 + 6H_2O$.
The carbohydrates that are not immediately used by the plant are stored in the form of $Starch$.

(N/A) The site of photosynthesis is the chloroplast,which is a green-coloured plastid found in plant cells.
$(b)$ The basic requirements for the process of photosynthesis are:
$(i)$ Carbon dioxide $(CO_2)$
$(ii)$ Water $(H_2O)$
$(iii)$ Sunlight (as an energy source)
$(iv)$ Chlorophyll (the photosynthetic pigment)

(N/A) $(i)$ The hormone secreted by the thyroid gland is thyroxine,which regulates the metabolism of carbohydrates,proteins,and fats in the body.
$(ii)$ The gland that secretes insulin is the pancreas. Insulin plays a crucial role in regulating blood sugar levels by facilitating the uptake of glucose into cells.
$(iii)$ The pituitary gland secretes several hormones,most notably the growth hormone $(GH)$,which regulates the growth and development of the body.

(N/A) $(i)$ Pepsin is secreted by the gastric glands present in the stomach wall.
$(ii)$ Salivary amylase is secreted by the salivary glands located in the mouth.
$(iii)$ Trypsin is secreted by the pancreas.
$(iv)$ Lipase is secreted by the pancreas.
$(b)$ $(i)$ The small intestine is the primary site for the absorption of digested food into the bloodstream.
$(ii)$ The large intestine is responsible for the absorption of water and salts from the undigested food material.

(N/A) The structure of a nephron is shown in the provided diagram,with the renal artery,Bowman's capsule,glomerulus,and collecting duct clearly labeled.
$(b)$ As the initial filtrate flows along the nephron tubule,the following four substances are selectively reabsorbed into the blood:
$(i)$ Glucose
$(ii)$ Amino acids
$(iii)$ Salts (such as $Na^+$,$Cl^-$)
$(iv)$ Water

(N/A) $(i)$ Keep a potted plant in a dark room for $48-72$ hours to destarch its leaves. (Fig. $(a)$)
$(ii)$ Cover a portion of a leaf on both sides with strips of black paper using paper clips. This prevents sunlight from reaching the covered area. (Fig. $(b)$)
$(iii)$ Place the plant in bright sunlight for $4-6$ hours.
$(iv)$ Detach the leaf and remove the black paper strips. Perform a starch test by boiling the leaf in alcohol to remove chlorophyll and then adding iodine solution.
$(v)$ The part of the leaf that was covered with black paper does not turn blue-black,indicating the absence of starch. (Fig. $(c)$)
$(vi)$ The uncovered part of the leaf turns blue-black,indicating the presence of starch. This proves that sunlight is essential for photosynthesis.

(N/A) The sectional view of the human heart shows the four chambers and major blood vessels. The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs. The right atrium receives deoxygenated blood from the body. The left ventricle pumps oxygenated blood to the rest of the body. The septum separates the right and left sides of the heart to prevent the mixing of oxygenated and deoxygenated blood.
$(b)$ $(i)$ Xylem: Transports water and dissolved minerals from the roots to the leaves.
$(ii)$ Phloem: Transports food (sucrose) synthesized in the leaves to other parts of the plant (translocation).
$(iii)$ Pulmonary vein: Transports oxygenated blood from the lungs to the left atrium of the heart.
$(iv)$ Vena cava: Transports deoxygenated blood from the body tissues to the right atrium of the heart.

(B) This happens due to the build-up of lactic acid in our muscles.
During vigorous exercise,the demand for energy increases,leading to a shortage of oxygen in our muscle cells.
Under these anaerobic conditions,the muscle cells switch to an alternative pathway where pyruvate is converted into lactic acid instead of entering the aerobic respiration cycle.
The accumulation of this lactic acid causes muscle fatigue and cramps.

(N/A) The $pancreas$ secretes a hormone called $insulin$ when the blood sugar level rises, which helps in regulating the glucose level in the blood.
The $pancreas$ also acts as a digestive gland and releases several digestive enzymes, such as $trypsin$ (which helps in the digestion of proteins) and $lipase$ (which helps in the digestion of fats).

(N/A) The heart consists of four chambers, each with a specific role in the circulatory system:

Chamber	Function
$Right \text{ atrium}$	Receives deoxygenated (impure) blood from the rest of the body via the $vena \text{ cava}$ and pumps it into the $right \text{ ventricle}$.
$Left \text{ atrium}$	Receives oxygenated (pure) blood from the lungs via the $pulmonary \text{ vein}$ and pumps it into the $left \text{ ventricle}$.
$Right \text{ ventricle}$	Receives deoxygenated blood from the $right \text{ atrium}$ and pumps it to the lungs for oxygenation via the $pulmonary \text{ artery}$.
$Left \text{ ventricle}$	Receives oxygenated blood from the $left \text{ atrium}$ and pumps it to the entire body via the $AORTA$ (the main artery).

(D) The opening and closing of the stomatal pore is regulated by the turgor pressure within the guard cells.
When water enters the guard cells,they become turgid and swell,causing the stomatal pore to open.
Conversely,when water leaves the guard cells,they become flaccid,causing the stomatal pore to close.
Therefore,the movement of water into and out of the guard cells is the primary factor determining the state of the stomata.

(A) Plants require nitrogen for the synthesis of proteins and other compounds.
Although nitrogen is abundant in the atmosphere,plants cannot absorb it directly in its gaseous form $(N_2)$.
Most plants absorb nitrogen from the soil primarily in the form of nitrates $(NO_3^-)$ and nitrites $(NO_2^-)$.
Some plants can also absorb nitrogen in the form of urea or ammonium compounds,which are converted into nitrates by soil bacteria.
Therefore,the forms in which most plants absorb nitrogen are nitrates and nitrites,and sometimes urea.

(B) The process of digestion begins in the mouth (buccal cavity).
Salivary glands secrete saliva,which contains the enzyme salivary amylase (also known as ptyalin).
This enzyme is the first to mix with food and it starts the breakdown of complex carbohydrates (starch) into simpler sugars like maltose.

(C) Salivary amylase is an enzyme present in the saliva that initiates the chemical digestion of carbohydrates.
It specifically acts on starch (a complex carbohydrate) and breaks it down into simpler sugars like maltose.
If salivary amylase is absent,the breakdown of starch into sugars in the mouth cavity will be significantly affected or inhibited.

(D) The stomach wall secretes gastric juice,which contains hydrochloric acid $(HCl)$,pepsin,and mucus.
$HCl$ creates an acidic medium necessary for the activation of the enzyme pepsin.
However,$HCl$ can be corrosive to the stomach lining.
Mucus is secreted by the goblet cells in the stomach lining to form a protective layer.
This layer prevents the acid from damaging the stomach wall,thus protecting it from erosion and ulcers.

(A) The liver produces bile,which is stored in the gallbladder. Bile is released into the duodenum,which is the first part of the small intestine. This bile helps in the emulsification of fats,breaking down large fat globules into smaller ones to facilitate digestion by enzymes.

(B) The iodine test is a chemical test used to detect the presence of starch in a sample.
When iodine solution ($I_2$ in $KI$) is added to a substance containing starch,it forms a starch-iodine complex,which results in a characteristic blue-black colour.
Since the rice water turned blue-black upon the addition of iodine,it confirms the presence of starch in the rice water.
Therefore,the correct option is $B$.

(C) The process of digestion begins in the mouth and continues in the stomach.
However,the final digestion of food,including carbohydrates,proteins,and fats,is completed in the small intestine.
The small intestine receives secretions from the liver (bile) and the pancreas (pancreatic juice),and its walls secrete intestinal juice.
These enzymes break down complex food molecules into their simplest absorbable forms,such as glucose,amino acids,and fatty acids,which are then absorbed into the bloodstream.

(D) Pancreatic juice contains several enzymes that play a crucial role in digestion.
$1$. $Trypsin$ is a proteolytic enzyme that breaks down proteins into smaller peptides.
$2$. $Lipase$ is an enzyme that acts on emulsified fats and breaks them down into fatty acids and glycerol.
Therefore,the correct function is that $trypsin$ digests proteins and $lipase$ digests emulsified fats.

(A) When we exhale,the air we breathe out contains a significant amount of $CO_2$ (carbon dioxide).
When this $CO_2$ is passed through lime water $(Ca(OH)_2)$,it reacts to form calcium carbonate $(CaCO_3)$,which is an insoluble white precipitate.
The chemical reaction is: $Ca(OH)_2 + CO_2 \rightarrow CaCO_3 + H_2O$.
This formation of calcium carbonate makes the lime water appear milky.

(B) The human heart functions as a double pump system:
$1$. The left atrium receives oxygenated blood from the lungs via pulmonary veins,not from the body. Thus,statement $(i)$ is false.
$2$. The left ventricle pumps oxygenated blood to the entire body through the aorta,and the right ventricle pumps deoxygenated blood to the lungs for oxygenation. Thus,statement $(ii)$ is true.
$3$. The left atrium transfers oxygenated blood to the left ventricle,not the right ventricle. Thus,statement $(iii)$ is false.
$4$. The right atrium receives deoxygenated blood from the body,and the left ventricle pumps oxygenated blood to the body. Thus,statement $(iv)$ is true.
Therefore,statements $(ii)$ and $(iv)$ are correct.

(C) The heart contains specialized structures called valves (such as the tricuspid,bicuspid,and semilunar valves).
These valves act as one-way doors that open to allow blood to flow in the correct direction and close tightly to prevent the backflow of blood during the contraction (systole) of the heart chambers.

(D) In single circulation,the heart receives only deoxygenated blood,which is then pumped to the gills for oxygenation and subsequently distributed to the rest of the body without returning to the heart. This type of circulation is characteristic of fishes.
$1$. $Labeo$ (Rohu),$Hippocampus$ (Sea horse),$Exocoetus$ (Flying fish),and $Anabas$ (Climbing perch) are all bony fishes.
$2$. $Chameleon$,$Salamander$,$Whale$,$Dolphin$,$Turtle$,$Hyla$,$Rana$,and $Draco$ are not fishes; they possess either double circulation or incomplete double circulation.
Therefore,the correct group exhibiting single circulation is $Hippocampus$,$Exocoetus$,and $Anabas$.

(A) In $Pisces$ (fishes),the heart is two-chambered,consisting of one atrium and one ventricle. The heart pumps deoxygenated blood to the gills for oxygenation. This oxygenated blood then goes directly to the rest of the body without returning to the heart. Thus,the heart only pumps deoxygenated blood. This is known as single circulation. In amphibians and reptiles,the heart is three-chambered (or partially four-chambered in reptiles),allowing for the pumping of both oxygenated and deoxygenated blood to the body tissues. Therefore,the correct group is $Pisces$ only.

(B) During inhalation,air enters through the nostrils.
From the nostrils,it passes into the nasal cavity and then into the pharynx.
The pharynx leads to the larynx (voice box).
From the larynx,air moves into the trachea (windpipe).
The trachea branches into bronchi,which further divide into bronchioles and finally reach the alveoli in the lungs for gas exchange.
Therefore,the correct sequence is: Nostrils $\rightarrow$ pharynx $\rightarrow$ larynx $\rightarrow$ trachea $\rightarrow$ alveoli.

(C) During the process of respiration,the exchange of gases ($O_2$ and $CO_2$) occurs in the $alveoli$ of the lungs.
$Alveoli$ are tiny,balloon-like structures present at the terminal ends of the bronchioles.
These structures provide a large surface area for the diffusion of gases between the air in the lungs and the blood in the surrounding capillaries.
The trachea and larynx are parts of the conducting zone and do not participate in gas exchange.

(D) Statement $(i)$ is correct: In yeast,during fermentation,pyruvate is converted into ethanol and carbon dioxide.
Statement $(ii)$ is incorrect: Fermentation is an anaerobic process,not an aerobic one.
Statement $(iii)$ is incorrect: Fermentation occurs in the cytoplasm,not in the mitochondria.
Statement $(iv)$ is correct: Fermentation is a type of anaerobic respiration that occurs in the absence of oxygen.
Therefore,statements $(i)$ and $(iv)$ are correct.

(A) During intense physical activity,such as playing cricket,the demand for energy in muscle cells increases significantly.
When the supply of oxygen is insufficient to meet this demand,muscle cells switch to anaerobic respiration.
In this process,the pyruvate produced from glucose breakdown is converted into lactic acid instead of entering the aerobic pathway (Krebs cycle).
The accumulation of lactic acid in the muscle tissues causes fatigue and painful muscle cramps.

(B) The process of urine formation and excretion in the human body follows a specific pathway:
$1$. Urine is produced in the kidneys through the process of filtration.
$2$. From the kidneys,urine travels through the ureters,which are thin tubes that carry urine to the bladder.
$3$. The urinary bladder acts as a storage organ for urine until it is ready to be expelled.
$4$. Finally,urine is expelled from the body through the urethra.
Therefore,the correct sequence is: kidney $\rightarrow$ ureter $\rightarrow$ urinary bladder $\rightarrow$ urethra.

(C) Life processes are the basic functions performed by living organisms to survive and maintain their body structure.
$1$. Organisms grow with time as they assimilate nutrients and build new cellular components.
$2$. Maintenance and repair of body structures are continuous processes to replace worn-out tissues.
$3$. Movement of molecules is essential for life; substances like oxygen,carbon dioxide,nutrients,and waste products constantly move between cells and the environment to sustain metabolism.
$4$. Energy is required for all life processes,including growth,repair,and transport.
Therefore,the statement that 'Movement of molecules does not take place among cells' is incorrect.

(B) The statement is $False$.
Excretion is defined as the biological process by which an organism eliminates metabolic waste products from its body.
While metabolic processes are chemical in nature,excretion itself is a physiological or biological process,not merely a chemical reaction.

(B) The statement is False.
While the liver is responsible for the formation of urea through the ornithine cycle (converting toxic ammonia into less toxic urea),the actual removal or filtration of nitrogenous wastes from the blood occurs in the kidneys.
The lungs are responsible for the exchange of gases ($CO_{2}$ and $O_{2}$),whereas the kidneys are the primary organs for the excretion of nitrogenous metabolic wastes.

(A) The statement is $True$. The urinary bladder is a muscular sac that stores urine produced by the kidneys. As the bladder fills with urine,its walls stretch,increasing the internal pressure. This expansion triggers stretch receptors in the bladder wall,which send nerve impulses to the central nervous system,creating the voluntary urge to micturate (urinate) through the urethra.

(B) The statement is $False$.
Kidneys are not located in the thoracic cavity.
They are located in the abdominal cavity, specifically in the retroperitoneal space, one on either side of the vertebral column (backbone).

(B) The statement is $False$. In the human heart,the walls of the ventricles are significantly thicker than those of the auricles (atria). This is because the ventricles are responsible for pumping blood out of the heart to the lungs (right ventricle) and to the rest of the body (left ventricle),which requires much higher pressure. The auricles only need to pump blood into the adjacent ventricles,which requires less force.