CBSE Questions for Class 11 Medical Biology Excretory Products And Their Elimination Quiz 2 - MCQExams.com

• Glucose is unavailable during prolonged fasting. 
• The body starts utilizing accumulated fat to meet the energy requirement.
• During the process of fat metabolism, it produces ketones which ultimately increases the blood ketone level. 
• These are excreted out by kidneys through urine. High levels lead to dehydration and change the chemical balance of the blood.

• Lungs are the respiratory organs which aid is exchange of air.
• Skin is the outer covering of body.
• Liver is the largest gland in the body and perform various functions such as detoxifying, metabolism etc.
• Hepatopancreas, a digestive gland is found in the digestive tract of arthropods and molluscs.

• Ascending limb of the loop of Henle is impermeable to water. Here water is not reabsorbed, rather sodium, potassium, magnesium, and chloride are reabsorbed and therefore the filtrate becomes hypotonic to blood plasma.
  

• Malpighian corpuscle (renal corpuscle) consists of Bowman's capsule and glomerulus. 
• Bowman's capsule is a cup-like structure at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. 
• A glomerulus is a network (as a tuft) of capillaries located in the Bowman's capsule, Bowman's capsule, and glomerulus, together form the Malphigian body or corpuscle. They carry out a process known as ultrafiltration.

Correct Option: B

Explanation:

• The colour of urine ranges from light yellow to rich amber.
• A healthy person's urine comprises water, urea, inorganic salts, creatinine, ammonia, and blood breakdown products.
• Haemoglobin produced by heme-containing dead RBCs produces urochromes, which are responsible for the yellow hue of a healthy person's urine.
• The metabolic activities of bacteria affect the colour of urine during microbial infection.

Hence, urochromes impart the yellow colour to the urine of a healthy person.

$$\textbf{Correct answer: A}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ Arginase is the enzyme used in the conversion of arginine to ornithine in the ornithine cycle. 

$$\bullet$$ In this process urea is released from arginine which is a less toxic product as compared to ammonia. 

$$\bullet$$ Here ornithine acts as the carrier of nitrogen and carbon atoms. 

$$\textbf{Option (B):}$$ 

$$\bullet$$ Ornithine transcarbamylase helps with the conversion of ornithine to citrulline.

$$\bullet$$ In the presence of carbamoyl phosphate entering the cycle, the conversion to citrulline takes place.

$$\textbf{Option (C):}$$ 

$$\bullet$$ Fumaric acid is not converted to arginine in the ornithine cycle. 

$$\bullet$$ Arginine is formed from argininosuccinate using the enzyme argininosuccinate lyase.

$$\textbf{Option (D):}$$ 

$$\bullet$$ Glycolysis is not directly associated with the ornithine cycle.

Hence, the correct answer is option (A).

• Blood cells and plasma proteins are not filtered through the glomerular capillaries because they are relatively larger in size. 
• The glomerular filtrate contains all the materials present in the blood except blood cells and most proteins, which are too large to cross the basement membrane of the glomerulus. 
• Hence albumin (protein) is not present in the glomerular filtrate.

Correct Option: B

Explanation:

• “Active Transport is defined as a process that involves the movement of molecules from a region of lower concentration to a region of higher concentration against a gradient or an obstacle with the use of external energy.” -NCERT
• Example: The absorption of glucose in the human gut, as well as the uptake of minerals or ions into plant root hair cells, are both instances of active transport.

Hence, active transport is the process wherein molecules (ions, compounds etc.) travel from a region of their lower concentration to the region of their higher concentration (i.e., against the gradient using ATP) using energy.

• Generally, the urine of a man under normal conditions does not contain] any glucose because the kidneys are able to reabsorb all of the filtered glucose from the tubular fluid back into the bloodstream. 
• The glomerulus filters blood and produces the glomerular filtrate. This filtrate contains water, glucose, salts and urea. Large molecules such as protein are too large to fit through the blood capillary walls.
• The bowman's capsule collects the filtrate and enters the tubules. 
• All glucose is reabsorbed immediately into the blood capillaries. As the rest of the filtrate travels through the tubules water and salts needed by the body are reabsorbed into the blood capillaries.

Correct Option: B

Explanation:

• Podocytes, also known as foot cells, are specialized cells with a unique shape that surround the glomerulus in the epithelial visceral inner layer of Bowman's capsule.
• The pedicers have foot-like appendages or extensions. As a result, they're known as foot cells.
• Squamous epithelium cells make up the outer wall of Bowman's capsule.

Hence, podocytes are present in the inner walls of the bowman’s capsule.