Mix Examples - Life Processes Questions in English

(B) The ventricles are responsible for pumping blood out of the heart to various organs of the body.
This process requires high pressure to circulate blood through the entire circulatory system.
Therefore,the ventricles have thicker and more muscular walls compared to the atria,which only receive blood and pump it into the ventricles.

(C) Platelet cells,also known as thrombocytes,are essential components of the blood. Their primary function is to circulate throughout the body and initiate the process of blood clotting (coagulation) at the site of an injury. This prevents excessive blood loss and helps in the healing process.

(B) The digestion of fat primarily takes place in the $Small \ intestine$.
First, bile salts from the liver emulsify large fat globules into smaller droplets to increase the surface area for enzyme action.
Then, the enzyme $Lipase$ (secreted by the pancreas) breaks down these emulsified fats into fatty acids and glycerol.

(B) Photosynthesis is the process by which green plants synthesize their food. This process takes place in specialized cell organelles known as chloroplasts. Chloroplasts contain the green pigment chlorophyll,which captures light energy to convert carbon dioxide and water into glucose.

(B) The raw materials required for photosynthesis are:
$(i)$ $CO_{2}$ (Carbon dioxide): Taken from the atmosphere through stomata.
$(ii)$ $H_{2}O$ (Water): Absorbed from the soil by the roots.
These substances,along with sunlight and chlorophyll,are used by plants to synthesize glucose.

(B) The kidneys are the primary excretory organs in the human body. They filter the blood to remove metabolic waste products. The main nitrogenous waste product filtered from the blood by the kidneys is $Urea$,which is produced in the liver during the breakdown of amino acids.

(N/A) In the nephron, as the filtrate moves along the tubule, substances like $glucose$, $amino \text{ } acids$, $salts$, and $water$ are selectively reabsorbed into the blood capillaries surrounding the nephron tubule. Any two of these can be mentioned, for example: $1$. $Glucose$ and $2$. $Amino \text{ } acids$.

(N/A) $(i)$ Fish heart has $2$ chambers (one atrium and one ventricle).
$(ii)$ Amphibian heart has $3$ chambers (two atria and one ventricle).
$(b)$ Mammals and birds are warm-blooded animals that maintain a constant body temperature. This process requires a significant amount of energy. Separating oxygenated and deoxygenated blood ensures a highly efficient supply of oxygen to the body tissues,which is essential for meeting these high energy demands.

(N/A) The protein-digesting enzyme present in pancreatic juice is $Trypsin$. The hormone secreted by the pancreas is $Insulin$.
$(b)$ Pancreatic juice contains enzymes like $Trypsin$ for protein digestion,$Lipase$ for fat digestion,and $Amylase$ for carbohydrate digestion. It also contains bicarbonate ions that neutralize the acidic chyme coming from the stomach,creating an alkaline environment necessary for the action of these enzymes.

(A) $(i)$ Filtration of blood occurs in the Glomerulus,which is a network of capillaries.
$(ii)$ Reabsorption of glucose and water primarily occurs in the Proximal Convoluted Tubule $(PCT)$ of the nephron.
$(iii)$ Secretion of salts and other substances to maintain the composition of the final filtrate occurs in the Distal Convoluted Tubule $(DCT)$.
$(iv)$ Collection of the final filtrate (urine) occurs in the Collecting Duct,which carries it to the renal pelvis.

(N/A) Renal artery: It carries oxygenated blood containing nitrogenous wastes from the aorta to the kidney for filtration.
$(b)$ Kidney: It is the primary excretory organ that filters the blood to remove metabolic wastes,excess water,and salts,thereby forming urine.
$(c)$ Ureter: It is a pair of thin muscular tubes that transport urine from the kidneys to the urinary bladder.
$(d)$ Urinary bladder: It is a muscular sac that stores urine temporarily until it is voided from the body through the urethra.

(N/A) $(i)$ Gastric glands: These are present in the walls of the stomach. They secrete $HCl$,a protein-digesting enzyme called pepsin,and mucus.
$(ii)$ Pancreas: This gland secretes pancreatic juice,which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats.

(N/A) The common features of respiratory organs in both aquatic and terrestrial animals are as follows:
$1$. Large surface area: Respiratory organs have a large surface area to facilitate the maximum exchange of gases.
$2$. Thin-walled: The surface of the respiratory organs is very thin to allow for easy diffusion of gases.
$3$. Richly supplied with blood: They are well-supplied with blood vessels to ensure efficient transport of oxygen and carbon dioxide.
$4$. Well protected: These organs are usually located inside the body or protected by structures to prevent damage and maintain a moist environment.

(A) During the process of digestion, complex food molecules are broken down into simpler, absorbable forms.
$1$. Carbohydrates are broken down into simple sugars, primarily $Glucose$.
$2$. Proteins are broken down into their basic building blocks, known as $Amino acids$.
$3$. Fats are broken down into $Fatty acids$ and $Glycerol$.

(A) During intense physical activity like running,the demand for energy in muscle cells increases rapidly.
When the oxygen supply is insufficient to meet this demand,muscle cells perform anaerobic respiration.
In this process,pyruvate is converted into lactic acid instead of entering the aerobic pathway.
The accumulation of lactic acid in the muscle fibers leads to muscle fatigue and cramps.

(B) Desert plants are adapted to arid environments where they keep their stomata closed during the day to prevent water loss through transpiration.
To perform photosynthesis,they take up $CO_2$ at night and convert it into an intermediate organic acid (like malic acid).
During the daytime,the energy absorbed by the chlorophyll from sunlight is used to process this stored intermediate molecule into glucose,allowing photosynthesis to occur without opening the stomata.

(N/A) $(i)$ Valves are needed in the heart to ensure that blood flows in only one direction and does not flow backward when the atria or ventricles contract.
$(ii)$ To prevent leakage,blood contains specialized cells called platelets. These platelets circulate throughout the body and plug any leakage by forming a clot at the site of an injury.

(N/A) $1$. Salivary amylase: It is secreted by salivary glands and breaks down starch into simpler sugars like maltose.
$2$. Pepsin: It is secreted by the gastric glands in the stomach and helps in the digestion of proteins into peptides/amino acids.
$3$. Trypsin: It is secreted by the pancreas and helps in the digestion of proteins in the small intestine.
$4$. Lipase: It is secreted by the pancreas and breaks down emulsified fats into fatty acids and glycerol.

(N/A) Plants store carbohydrates in the form of $Starch$,which serves as their internal energy reserve.
No,animals do not have the same energy reserve. Animals store carbohydrates in the form of $Glycogen$ as their internal energy reserve.

(N/A) Salivary amylase acts on starch present in the food within the buccal cavity.
It breaks down complex starch molecules into simpler sugars,specifically maltose,which is the initial product of this enzymatic action.

(D) The direction of diffusion in plants is primarily determined by the following factors:
$1$. Concentration gradient: Molecules move from a region of higher concentration to a region of lower concentration.
$2$. Permeability of the membrane: The selective nature of the cell membrane regulates the movement of substances.
$3$. Environmental conditions: Factors like temperature and pressure significantly influence the rate and direction of diffusion.
$4$. Requirement of the plant: The metabolic needs of the plant cells dictate the uptake or release of specific substances.
Therefore,all these factors collectively maintain the direction of diffusion.

(N/A) $(i)$ Xylem: Transports water and dissolved minerals from the roots to the rest of the plant.
$(ii)$ Pulmonary artery: Transports deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation.
$(iii)$ Pulmonary vein: Transports oxygenated blood from the lungs to the left atrium of the heart.
$(iv)$ Phloem: Transports synthesized food (sucrose/sugars) from the leaves to other parts of the plant.

(B) $I$ would suggest a meat-based diet for the bear.
Reasoning: Herbivores,which consume plant-based diets,require a longer small intestine to allow sufficient time for the digestion of cellulose. Since a significant portion of the bear's small intestine has been removed,its ability to digest complex plant matter is compromised. Meat is easier and faster to digest compared to plant material,making it a more suitable diet for an animal with a shortened digestive tract.

(N/A) $1$. Gaseous exchange: Stomata facilitate the exchange of gases like $CO_2$ and $O_2$ between the atmosphere and the internal tissues of the leaf,which is essential for photosynthesis and respiration.
$2$. Transpiration: Stomata allow for the loss of water in the form of water vapor from the aerial parts of the plant,a process known as transpiration,which helps in the upward movement of water and minerals from the roots.

(N/A) The food coming from the stomach is acidic in nature. Bile juice makes this food alkaline so that pancreatic enzymes can act upon it.
Bile salts present in the bile juice break down large fat globules into smaller globules,a process known as emulsification.
This increases the surface area of the fat,thereby significantly increasing the efficiency of lipase enzyme action.

(N/A) The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration.
Functions:
$(i)$ It helps in the absorption and upward movement of water and minerals dissolved in it from roots to the leaves.
$(ii)$ It helps in the regulation of plant temperature by providing a cooling effect.

(N/A) Paramecium is a unicellular organism that follows holozoic nutrition.
It possesses a specific region known as the cytostome or oral groove for food ingestion.
The entire surface of the Paramecium is covered with hair-like structures called cilia.
These cilia beat in a coordinated rhythmic motion,creating water currents that sweep food particles (like bacteria) towards the oral groove.
Once the food enters the oral groove,it is engulfed into a food vacuole,where digestion occurs.

(N/A) Rings of cartilage are present in the trachea to prevent it from collapsing when there is no air inside it,ensuring that the airway remains open for breathing.
$(b)$ $(i)$ Mucus protects the inner lining of the stomach from the corrosive action of $HCl$ under normal conditions.
$(ii)$ Mucus lubricates the food,making it smoother so that it can move easily through the alimentary canal.

(N/A) In multicellular organisms,cells are not in direct contact with the external environment. Specialized tissues are responsible for the uptake of food and oxygen at specific sites. Since these substances are required by all cells throughout the body,a transportation system is essential to move them from the site of absorption to all other parts.
$(b)$ Metabolic activities within an organism produce various waste products,many of which are toxic or harmful if allowed to accumulate. An excretory system is required to filter and remove these harmful by-products from the body to maintain homeostasis.

(N/A) Transportation of materials is essential in animals for the following reasons:
$1$. It ensures the distribution of vital substances like food,oxygen,and water to all cells of the body.
$2$. It facilitates the removal of metabolic waste products from the cells to the excretory organs,from where they are expelled from the body.
$3$. It helps in maintaining a uniform internal environment,including the regulation of body temperature and pressure.

(N/A) The saliva present in the mouth contains an enzyme called salivary amylase,which breaks down the starch present in the bread into simple sugars. This is why a piece of bread tastes sweet when chewed for some time.
$(b)$ Cellulose is a complex carbohydrate that requires specific enzymes and a longer time for digestion. Herbivorous animals like cows possess a specialized stomach (rumen) and a longer small intestine,which allow for the fermentation and digestion of cellulose by symbiotic bacteria. In contrast,human beings lack the necessary enzymes and the specialized digestive tract to break down cellulose. Therefore,it remains undigested in humans and acts as roughage,which helps in bowel movement.

(N/A) Mucus protects the inner lining of the stomach from the action of the acid under normal conditions.
$(b)$ The exit of food from the stomach is regulated by sphincter muscles,which release it in small amounts into the small intestine.
$(c)$ From the stomach,food enters the small intestine.

(N/A) The food coming from the stomach is acidic in nature due to the presence of $HCl$.
$(b)$ $(i)$ The inner lining of the small intestine has numerous finger-like projections called villi,which significantly increase the surface area for the absorption of digested food.
$(ii)$ The small intestine is a long,highly coiled tube,which ensures that the food stays in the intestine for a longer duration,allowing for maximum absorption of nutrients.

(N/A) The extensively coiled structure of the alimentary canal is the small intestine.
$(b)$ The length of the small intestine varies in different animals depending on the type of food they consume. Herbivores,which feed on grass,require a longer small intestine to facilitate the digestion of cellulose. In contrast,carnivores possess a shorter small intestine because meat is comparatively easier to digest.

(N/A) The chemical equation for photosynthesis is: $6CO_2 + 6H_2O \xrightarrow[\text{Chlorophyll}]{\text{Sunlight}} C_6H_{12}O_6 + 6O_2$.
The three main events that occur during photosynthesis are:
$(i)$ Absorption of light energy by chlorophyll.
$(ii)$ Conversion of light energy into chemical energy and the splitting of water molecules into hydrogen and oxygen.
$(iii)$ Reduction of $CO_2$ into carbohydrates.
In desert plants,the process is adapted to conserve water. They take up $CO_2$ at night and prepare an intermediate product. During the day,when chlorophyll absorbs sunlight,this energy is used to act upon the intermediate product to synthesize carbohydrates.

(N/A) The product formed is lactic acid.
The accumulation of lactic acid in the muscles leads to muscle cramps.
$(b)$ In yeast,fermentation results in the production of ethanol and carbon dioxide. In contrast,aerobic respiration results in the production of carbon dioxide and water. Additionally,the amount of energy $(ATP)$ released during fermentation is significantly lower than that released during aerobic respiration.

(A) Organism $B$ is undergoing aerobic respiration because it produces a high yield of $38$ $ATP$ molecules per glucose molecule.
$(b)$ Organism $A$ is undergoing anaerobic respiration because it produces a low yield of only $2$ $ATP$ molecules per glucose molecule.
$(c)$ Organism $A$ can convert glucose into alcohol through the process of fermentation.
$(d)$ Yeast is an organism that behaves like $A$ (undergoes anaerobic respiration).
$(e)$ Human beings and aerobic bacteria are two examples of organisms that behave like $B$ (undergo aerobic respiration).

(N/A) When muscles work harder,they require more oxygen and nutrients. Consequently,the heart beats faster to increase the rate of blood circulation to meet this increased demand.
$(b)$ The circulatory system (or cardiovascular system) is directly affected when a person suffers from heart disease.
$(c)$ White blood cells (also known as leukocytes or $WBCs$) increase in number during an infection to help the body fight against pathogens.

(N/A) If peristaltic movements do not occur,the food will not be pushed forward into the stomach,leading to an inability to swallow or digest food properly.
$(b)$ If there are no platelets in the blood,the blood will not clot in the event of an injury,which could lead to excessive and potentially fatal blood loss.
$(c)$ In the absence of rings of cartilage,the trachea (windpipe) would collapse during inhalation because the air pressure inside the tube decreases,potentially obstructing the airway.

(N/A) Lymph is a clear,colourless fluid that acts as a circulatory medium within the lymphatic system. It is formed from the interstitial fluid that enters the lymphatic capillaries.
Composition difference:
Lymph is similar to blood plasma in composition but contains significantly less protein and lacks red blood cells and platelets.
Direction of flow:
Lymph flows in a unidirectional manner,moving from the interstitial spaces (tissues) towards the heart.
Functions of the lymphatic system:
$(i)$ It transports digested and absorbed fats from the intestine into the bloodstream.
(ii) It drains excess interstitial fluid from the extracellular spaces back into the blood,maintaining fluid balance.

(N/A) $Translocation$: The transport of food prepared in the leaves to other parts of the plant is known as $translocation$.
$Translocation$ is essential for plants to supply food to all parts of the plant. Food is required for producing energy during its oxidation,and this energy is necessary for all plant parts to perform their metabolic activities.
$(i)$ Sugars are synthesized in the leaves through photosynthesis and then transported to storage organs such as roots,fruits,and seeds.
$(ii)$ Hormones are synthesized primarily at the tips of the stems (shoot apices) and the tips of the roots (root apices).

(A) The glands associated with the digestion of starch are:
$1$. Salivary glands: Secrete salivary amylase,which breaks down starch into simpler sugars in the mouth.
$2$. Pancreas: Secretes pancreatic amylase,which digests starch in the small intestine.
$3$. Intestinal glands: Secrete intestinal amylase,which completes the digestion of starch into glucose.
Maintenance of $pH$:
- In the stomach: The gastric glands secrete Hydrochloric acid $(HCl)$,which creates an acidic medium (low $pH$) necessary for the activation of the enzyme pepsin.
- In the small intestine: The acidic food coming from the stomach is made alkaline by bile juice (from the liver) and pancreatic juice (from the pancreas),which is necessary for the action of pancreatic enzymes.

(N/A) $(i)$ Liver.
$(ii)$ Pancreas.
$(iii)$ Small intestine.
$(b)$ Villi are numerous finger-like projections present in the inner lining of the small intestine.
Function: They increase the surface area for the absorption of digested food.

(N/A) The three types of blood vessels in the human circulatory system are arteries, veins, and capillaries. Their functions are summarized in the table below:

Blood Vessel	Function
Arteries	They carry oxygenated blood away from the heart to various organs of the body.
Veins	They collect deoxygenated blood from different organs and bring it back to the heart.
Capillaries	They are thin-walled vessels where the exchange of materials (nutrients, gases, and waste) between the blood and surrounding cells takes place.

(N/A) When adrenaline is secreted into the blood,the heart beats faster,which results in the supply of more oxygen to our muscles.
The blood supply to the digestive system and skin is reduced due to the contraction of muscles around small arteries in these organs.
This diverts the blood to our skeletal muscles to prepare the body for 'fight or flight' responses.
The breathing rate also increases because of the contractions of the diaphragm and the rib muscles,allowing for increased oxygen intake.

(N/A) $(i)$ Kidney
$(ii)$ Urinary bladder
$(iii)$ Ureter
$(iv)$ Urethra
$(b)$ The amount of water reabsorbed in the nephron depends on two main factors:
$1$. The amount of excess water present in the body.
$2$. The amount of dissolved nitrogenous wastes that need to be excreted.

(N/A) $(i)$ Nasal passage
$(ii)$ Bronchioles
$(iii)$ Alveoli
$(iv)$ Diaphragm
$(b)$ Since the amount of dissolved oxygen in water is fairly low compared to the amount of oxygen in the air,aquatic organisms must breathe much faster to obtain sufficient oxygen for their metabolic needs compared to terrestrial organisms.

(N/A)

Arteries	Veins
$(i)$ They carry blood from the heart to various organs of the body.	$(i)$ They collect the blood from different organs and bring it back to the heart.
$(ii)$ They have thick,elastic walls.	$(ii)$ They have thin walls.
$(iii)$ They do not have valves.	$(iii)$ They have valves.

(N/A) The digestive system in humans is associated with several glands that produce secretions essential for digestion. Three such glands and their secretions are as follows:

Name of the gland	Secretions produced
Salivary glands	Saliva (contains salivary amylase/ptyalin)
Gastric glands	$HCl$, mucus, and pepsin
Liver	Bile juice
Pancreas	Pancreatic juice (contains trypsin, lipase, and amylase)
Intestinal glands	Intestinal juice

(N/A) $(i)$ Gall bladder
$(ii)$ Liver
$(b)$ Pancreatic juice contains several enzymes. One such enzyme is Trypsin,which digests proteins into amino acids. Another is Lipase,which breaks down emulsified fats into fatty acids and glycerol.
$(c)$ Peristaltic movements are the rhythmic contraction and relaxation of the muscles in the lining of the alimentary canal,which push the food forward through the digestive tract.