Free Life Processes 03 Practice Test - 10th Grade
Question 1
Arrange the following in the correct sequence:
1. Urine enters the ureter.
2. Urine is stored in the urinary bladder.
3. Some substances in the initial filtrate are selectively reabsorbed.
1 → 2 → 3
2 → 3 → 1
3 → 1 → 2
3 → 2 → 1
SOLUTION
Solution : C
Each kidney has a large number of filtration units called nephrons, packed close together. Some substances in the initial filtrate are selectively reabsorbed as the urine flows along the tubular part of the nephron. The urine formed in each kidney eventually enters a collecting tube, the ureter, which connects the kidney to the urinary bladder. Urine is stored in the urinary bladder until the pressure in the expanded bladder leads to the urge to pass it out through the urethra.
Question 2
What is/are the end product(s) of fat digestion?
Glucose
Fatty acids
Glycerol
Amino acids
SOLUTION
Solution : B and C
Bile is a green fluid secreted by the liver that helps in breaking down large fat molecules into smaller globules to ease it's digestion process. The actual digestion of these small fat globules is done by the intestinal juices, which convert fats into fatty acids and glycerol.
Question 3
Saliva in the mouth converts ________ into _________ .
proteins, amino acids
glycogen, glucose
starch, maltose
fats, vitamins
SOLUTION
Solution : C
Saliva contains the enzyme salivary amylase. It breaks down starch into simpler molecules such as maltose. Starch is a polysaccharide made up of many units of glucose. Maltose, on the other hand is a disaccharide produced when starch is broken down by amylase.
Question 4
What happens to the unused carbohydrates produced in the plant body?
Gets broken down and dissipated as heat.
Stored in the form of starch for future use.
Transported to stem in the form of glycogen.
Expelled from plant body through excretion.
SOLUTION
Solution : B
Excess or unused carbohydrates produced during photosynthesis are stored in the form of starch (polysaccharide/polymer of simple glucose molecules) as a reserve of energy for future use in various parts of the plant body.
Question 5
Which of the following help veins to prevent the backflow of blood?
SOLUTION
Solution : B
Veins collect blood from different parts of the body and bring it back to the heart. They do not need thick walls because the blood is no longer under pressure, but instead, they have valves to ensure that the blood flows only in one direction towards the heart.
Question 6
Where does digestion of proteins take place?
SOLUTION
Solution : B
The digestion of proteins starts in the stomach by the action of gastric juices produced by the walls of the stomach. Further, it also takes place in the duodenum and ileum of the small intestine under the action of pancreatic and intestinal juices respectively.
Question 7
Exchange of gases in the body takes place by which of the following mechanisms?
Osmosis
Diffusion
Active transport
Counter-current exchange
SOLUTION
Solution : B
Diffusion is the movement of a substance from an area of high concentration to an area of low concentration. The exchange of gases take place in the millions of alveoli in the lungs and the capillaries that envelop them. Due to the difference in concentration, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli.
Question 8
What could be the possible explanation for the evolution of four-chambered heart in mammals as opposed to two-chambered heart in fishes?
Fishes do not require energy to maintain their body temperature.
Fishes have efficient gills.
Mammals have more complex structure than fishes.
Fishes can store more energy than mammals.
SOLUTION
Solution : A and C
In fishes and reptiles, the heart is two-chambered and there is mixing of oxygenated and deoxygenated blood. They are cold blooded (the body temperature varies according to the surrounding temperature), so energy is required only for locomotion and hence less amount of oxygen is sufficient in them. Birds and mammals are warm blooded, so more energy is required to keep up the body temperature. To maintain high energy requirements of the body, more oxygen supply is required. Therefore, the heart has four chambers and oxygenated blood and deoxygenated blood is kept strictly separated. Also, complexities in the body structure and different mechanisms have increased with evolution. Therefore the mechanism of circulation has also evolved.
Question 9
An instrument that measures blood pressure is known as _______ .
SOLUTION
Solution : D
The force that blood exerts against the wall of a blood vessel is known as blood pressure. Blood pressure is measured with an instrument called sphygmomanometre. It consists of an inflatable rubber cuff, which is wrapped around the upper arm and is connected to an apparatus that records blood pressure.
Question 10
Statement 1: Lungs become empty after forceful expiration
Statement 2: The forcefully exhaled air is called residual volume of air.
SOLUTION
Solution : D
Lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released. Some volume of air is present in the lungs even after forceful expiration.