BHARATH COACHING CENTRE th 10 CBSE … cbse science … · growth, transport, synthesis, regulation, nutrition A. A butterfly sucking the nectar from the flowers in a garden. A butterfly

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Class 10 - Biology - CH6 - Life Processes

MCQs, NCERT Chapter Solutions and other Q & A

Q1. The kidneys in human beings are a part of the system for

(a) nutrition.

(b) respiration.

(c) excretion.

(d) transportation.

Q2. The xylem in plants are responsible for

(a) transport of water.

(b) transport of food.

(c) transport of amino acids.

(d) transport of oxygen.

Q3. The autotrophic mode of nutrition requires

(a) carbon dioxide and water.

(b) chlorophyll.

(c) sunlight.

(d) all of the above.

Q4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in

(a) cytoplasm.

(b) mitochondria.

(c) chloroplast.

(d) nucleus.




Q5. Movement of food through oesophagus is due to

(a) Lubrication by saliva

(b) Peristalsis

(c) Gravitational Pull

(d) All of the above

Q6. Where is bile produced?

(a) Gall bladder

(b) Blood

(c) Liver

(d) Spleen

Q7: In normal expiration, the diaphragm is

(a) Arched

(b) Flattened

(c) Perforated

(d) None of these

Q8: The correct pathway of blood in circulatory system is

(a) atria → ventricles → arteries → veins

(b) ventricles → atria → veins → arteries

(c) ventricles → veins → arteries → atria

(d) veins → ventricles → atria → arteries

Q9: Respiration is a process in which

(a) Energy is stored in the form of ADP

(b) Energy is released and stored in the form of ATP

(c) Energy is used up

(d) Energy is not released at all.

Q10: Name an organ which is part of two body systems.

Answer: Pancreas which if part of

Endocrine System

Digestive System




Q11: Why do raw bread taste sweeter on mastication?

Answer: It is because salivary glands secrete Salivary Amylase which converts starch into

sugars.

Q12: How are fats digested in our bodies? Where does this process take place?

Answer: The small intestine is the site of the complete digestion of fats. Fats are present in

the intestine in the form of large globules which makes it difficult for enzymes to act on

them. Bile juice from the liver accomplishes this. Bile salts emulsify these large globules of

fats and break them down into smaller globules increasing the efficiency of enzyme action.

The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting

proteins and lipase for breaking down emulsified fats. The walls of the small intestine

contain glands which secrete intestinal juice. The enzymes present in it finally convert the

fats into fatty acids and glycerol.

Q13: What is the role of saliva in the digestion of food?

Answer: Saliva is a fluid which is secreted by the salivary glands. It helps in digestion of

food by following ways:

Saliva contains a digestive enzyme called salivary amylase, which breaks down starch into

sugars (maltose).

It cleans the mouth cavity and tends to destroy germs that cause teeth decay. It contains

lysozymes which help in destroying the bacteria.

It moistens and lubricates food which again helps in swallowing.

It acts as solvent, dissolving some food particles to stimulate taste buds of the tongue.

Q14: Why will simple diffusion not meet the requirement of human beings?

Answer: All cells of body are not in direct contact with the environment. In humans the

energy requirements are high. Waste produced is more due to active metabolism.

Therefore simple diffusion does not meet the oxygen requirement of human beings.

Q15: What criteria do we use to decide whether something is alive?

Answer: Following criteria may be used to define whether something is alive:

It is an organized system of molecules that captures energy and nutrients to grow by

molecular movements,

It has the ability to reproduce at some point in its life cycle, and

It has the potential to evolve in response to changes in the environment.

Q16: After long running, you may experience cramps in your leg muscles. Whats the reason

behind this?

Answer: It is due to sudden build up of lactic acid (because of lack of oxygen) in our

muscles after long exercise. It causes muscular cramps in our leg muscles.




Q17: What processes would you consider essential for maintaining life?

Answer: Various life processes are essential for maintaining life. Some are:

Nutrition

Respiration

Excretion

Transportation

Q18: How do villi enhance absorption of food in the intestine?

Answer:

Increased surface area

Highly vascular

Q19: Why bile juice is considered important even though it does not contain any digestive

enzymes?

Answer: Bile juice is important for the following reasons:

It contains bile salts and bile pigments that emulsify fats.

Contains NaHCO3 that neutralizes the acidic medium of the food in small intestine.

Q20: Which organs secrete the following enzymes:

(i) Trypsin

(ii) Pepsin

Answer: (i) Trypsin - Pancreas (ii) Pepsin - Gastric lining of Stomach

Q21: Name the factors that affect photosynthesis.

Answer:

Light Intensity, its quality and duration.

Temperature

Water Availability

CO3 availability

Other Factors like age and histology of leaf, amount of chlorophyll present

Q22: Name the vestigeal part of human alimentary canal?

Answer: vermiform appendix or caecal

Q23: What is the name given to rhythmic wave like manner occurring in alimentary canal?

Answer: Peristalsis or Peristaltic movements




Q24: The bark of woody plants is dead but the inner layers inside the bark are living. How

do they get oxygen and release carbon dioxide?

Answer: Through lenticels

Q25: What are lenticels?

Answer: Lenticels are portions of the periderm (bark) with numerous intercellular spaces.

Their purpose is to allow gas exchange through the compactly arranged cork cells of the

bark, which otherwise presents an impermeable barrier to the passage of water and gases.

Q26: How does photosynthesis occur?

Answer: The process of photosynthesis is completed in two steps:

light reaction

dark reaction

i) Light reaction: The first step of photosynthesis occurs in the presence of light. During

this step, chlorophyll contained in the chloroplast of plant cells absorbs light energy. This

energy is converted into another form, which can be supplied for the completion of the

dark reaction.

ii) Dark reaction: This second step of photosynthesis does not require light, and is called

dark reaction. It can also carry on in the presence of light. During this step, energy

generated during light reaction is used to combine carbon dioxide and water molecules to

form energy rich compounds, such as glucose. Oxygen is also released in this process.

The following equation summarizes the raw materials and products of photosynthetic

process:

RAW MATERIALS PRODUCTS

sunlight

6CO2 + 12H2O ----------------> C6H12O6 + 6H2O + 6O2

carbon water chlorophyll glucose water oxygen

dioxide

Q27: Name the mode of nutrition in an organism that uses simple substances like CO2 and

water to prepare food inside its body?

Answer: Autotrophic mode of nutrition.

Q28: What are the differences between autotrophic nutrition and heterotrophic nutrition?

Answer:

Autotrophic

Nutrition Hetrotrophic




Nutrition

1 Green plants are self-dependent, because they

synthesize their own food materials by photosynthesis. Such mode of nutrition is

described as autotrophic nutrition. Organisms which depend upon plants or

other organisms for their nutrition.

2 Green Plants (producers) are autotrophs. Non-Green Plants, Animals, Parasites are

hetrotrophs (consumers).

Q29: Read following statements from A to E and identify the relevant life process from the

following word list.

growth, transport, synthesis, regulation, nutrition

A. A butterfly sucking the nectar from the flowers in a garden.

B. A boy shouts with excitement when his school team wins the match on the last ball.

C. After finishing lunch, Mohan's blood distributes the food molecules to different cells of

his body.

D. Green plants prepares starch (complex substance) from simpler chemicals.

E. Radha finds her height has increased by 4 cm since her last birthday.

Answer:

A-nutrition

B- regulation

C- transport

D- synthesis

E- growth

Q30: What is osmoregulation?

Answer: The regulation of the water content of the cell is called osmoregulation.

Q31: What are the different ways in which glucose is oxidized to provide energy in various

organisms?

Answer: Breaking down of glucouse involves two step process. In the first step, it is broken

into three carbon molecule called pyruvate. The pyruvate is further broken down into

energy in following different ways in various organisms:

Aerobic Respiration: In this case, pyruvate is broken down into water and carbon dioxide

along with release of energy. It commonly occurs in mitochondria of cells.

Anaerobic Respiration in Yeast: In yeast cells during fermentation pyruvate is converted

into ethanol and carbon dioxide in the absence of oxygen.




Anaerobic Respiration in Muscles: Due to lack of oxygen, e.g. during vigorous running or

exercise, in human muscles, pyruvate is converted into lactic acid.

Q31: Which organ of the plant body helps in osmo-regulation?

Answer: Leaves

Q32: Which organelle of the cell in animals helps in osmo-regulation?

Answer: Contractile Vacuole.

Q33: If kidney fails to reabsorb water, the tissues would

(a) remain unaffected

(b) shrink to shrivel

(c) absorb water from blood

(d) take more oxygen from blood

Answer: (c) absorb water from blood. This condition is called Oedma or Dropsy

Q34: How does transpiration pull help in ascent of sap?

Answer: Water column builds up as a result of cohesion and adhesion forces. The negative

pressure in the upper tissues results in upward pull of water.

Q35: In what form excretion takes place in plants?

Answer: Plants produce secondary metabolites like organic acids, tannin, resins, latex,

gums etc.

Q36(NCERT): What are the components of the transport system in highly organised plants?

Answer: The transport system of organised plants consist of xylem and phloem. Xylem

which have vessels and tracheids which transport water and minerals from root to other

parts of the plant. Phloem which consists of sieve tubes, sieve cells and companion cells

transport food from leaves to storage organs and other parts of the plant. In xylem, the

transport is unidirectional i.e. from root upward while in phloem, it is bidirectional.

Q37: What is meant by double circulation? Mention its advantages.

Answer: In human beings and other vertegrates, the blood goes through heart twice during

each cycle. This process is known as double circulation. Deoxygenated blood enters

through right auricle and then it enters right ventricle from where it is pumped to lungs for

oxygenation. From lungs after oxygenation it comes to left auricle and enters left ventricle

from where it is pumped to various parts of body.

Advantages:

It helps in keeping oxygenated and De-oxygenated blood completely separated.

It increases the efficiency of oxygen in the body.




Excellent youtube video explaining Circulatory System (credits: Paul Andersen,

bozemanbiology )

Q38: Who has longer small intestine tiger or cow?

Answer: Cow because it has to digest cellulose requiring an elaborate digestion. Most of the

plant eaters (ruminants) have to undergo additional process of digestion i.e. break the

cellulose wall and digest it.

Q39: Leaves of a healthy potted plant are coated with Vaseline to block the stomata. Will

this plant remain healthy for long? State three reasons to support your answer.

Answer: No the plant will not remain healthy because no exchange of gases are taking

place. It will lead to:

low respiration

no photosynthesis occur

no transpiration.

Hence plant will not remain healthy and may die eventually.

Q40: Outline inhalation-exhalation cycle.

Answer:

Inhalation: Lowering of diaphragm → rising of rib cage → Gas (O2) passes to Alveoli

Exhalation: Air is forced out → Rising of diaphragm → lowering of ribcage

Q41 (CBSE): Haemoglobin is a type of

(a) Carbohydrate

(b) Skin Pigment

(c) Vitamin

(d) Respiratory Pigment

Q42: What are the components of the transport system in human beings? What are the

functions of these components?

Answer: The main components of the transport system in human beings are:

heart,

blood, and

blood vessels.

❶ Heart pumps oxygenated blood throughout the body. It receives deoxygenated blood

from various parts of the body and transports this impure blood to the lungs for

oxygenation.




❷Blood is a fluid connective tissue and it helps in the transport of oxygen, nutrients, CO2,

and nitrogenous wastes.

❸The blood vessels (arteries, veins, and capillaries) carry blood either away from the

heart to various organs or from various organs back to the heart.

It is a double circulatory system in human body.

Q43: Why is it necessary to separate oxygenated and deoxygenated blood in mammals and

birds?

Answer: Warm-blooded animals like birds and mammals maintain a constant body

temperature under different temperature conditions. They cool themselves in a hotter

environment and warm their bodies in a cooler environment. Therefore, these animals

need more energy to maintain their body temperature. This requires more cellular

respiration which means more oxygen (O2). Therefore it is more efficient if mammals and

birds keep separate oxygenated and deoxygenated blood.

Q44(IMP): Why is there extra air in our lungs after exhaling?

Answer: This extra air is called residual volume of air. During the breathing cycle, when air

is taken

in and let out, the 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. Also we need to

do extra work to empty and refill the lungs, if there is no residual volume of air inside the

lungs.

Q46: Which cell are the site of exchange of gases?

Answer: Alveoli

Q47: How are the lungs designed in human beings to maximize the area for exchange of

gases?

Answer:Inside the lungs, the blood capillaries surround the alveoli. The exchange of gases

takes place between the blood of the capillaries and the gases present in the alveoli. Thus

alveoli are the site for exchange of gases.

During the process of inhalation, the lungs get filled up with air as ribs are lifted up and

diaphragm is flattened.

Air is sucked into the lungs and fills the expanded alveoli. Each lung contains 300-400

million alveoli. These numerous alveoli increase the surface area for gaseous exchange

making the process of respiration more efficient.

The blood brings carbon dioxide from the rest of the body for release into the alveoli, and

the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be

transported to all the cells in the body.

Q48: Why blood is necessary for oxygen delivery to all parts of the body in larger animals?

Answer:




Since the body size of animals is large, the diffusion pressure alone cannot take care of

oxygen delivery to all parts of the body.

Instead, respiratory pigments take up oxygen from the air in the lungs and carry it to

tissues which are deficient in oxygen before releasing it. In human beings, the respiratory

pigment is haemoglobin which has a very high affinity for oxygen.

This pigment is present in the red blood corpuscles. Carbon dioxide is more soluble in

water than oxygen is and hence is mostly transported in the dissolved form in our blood.

Q49: Define homeostasis.

Answer: The series of physical and chemical processes that work to maintain an internal

equilibrium is called homeostasis.

Q50: Name the organ systems that help us maintain homeostasis.

Answer: Circulatory System and Excretory System.

Q51: Wastes concentrated in the tubules of Bowman’s capsule are called ____.

(a) salts.

(b) juices

(c) urine

(d) amino acids

Q52: What in kidneys is analogous to alveloli in lungs?

Answer: Nephrons.

Q53(CBSE 2011): State the role and function of lymph in human transport system.

Answer: Lymph (like blood) is a circulatory fluid. It flows in the lymph vessels.

Lymph (also called tissue fluid) is colourless.

It consists of lymphocytes which kills germs and protect the human body from infections.

Lymph carries digested and absorbed fat from intestine.

It drains excess fluid from extra cellular space back into the blood.

Its flow is unidirectional i.e. from tissues → lymph capillaries → veins → heart.

Q54: What is the basic reason of urine production?

Answer: Blood carries nitrogenous waste in the form of urea or uric acid which needs to be

removed. It is done by kidneys by filtering the blood and removing uric acid in the form of

urine.

Q55: (CBSE 2011): State the role of kidneys in human transport system.

Answer:




Remove or excrete nitrogenous wastes

Regulate water content of the body (osmo-regulation).

Maintain mineral balance in blood.

Q56: Who discovered systemic blood circulation system in human body?

Answer: William Harvey in 1628

Before that people believe, it is the same tubes carry the blood and blood is formed in liver.

Q57: What is pulmonary circulation and systemic circulation?

Answer: Humans have a double circulatory system. The right side of the four chambered

heart pumps blood to the lungs only and is called the pulmonary circulation.

The left side of the heart pumps blood to the rest of the body is called the systemic

circulation.

Q60: Which fluid is also know as tissue fluid?

Answer: Lymph

Q61: What is sphygmomanometer?

Answer: In layman terms it is called blood pressure apparatus which is used to measure

blood pressure of humans.

Q62: What is the function of ureter?

Answer: Transports urine from kidneys to bladder.

Q63(PreMed): Assertion and Reason Type

Assertion: Bile is essential for fat digestion

Reason: Fats cannot be digested without emulsification

Use the following Key to choose the appropriate answer.

(a) Both Assertion & Reason are True & Reason is a correct explanation of the

Assertion.

(b) If both Assertion & Reason are True but Reason is not a correct explanation of the

Assertion.

(c) If Assertion is True but the Reason is False.

(d) If both Assertion and Reason are False

Q64: Chyme is ____.

(a) Digestive enzyme secreted by stomach.

(b) Hormone secreted by islets of Pancreas




(c) food which enters into intestine from stomach.

(d) Part of bile juice which stores in gall bladder.

Q65: What is the nature of Chyme? Acidic or Basic or Neutral?

Answer: Acidic.

Q66: During daytime transpiration and photosynthesis are interlinked. What do you mean

by this statement?

Answer: During daytime, stomata is open to diffuse in Carbon Oxide gas for photosynthesis.

In parallel, it also facilitates transpiration. Therefore, during daytime the process of

transpiration and photosynthesis are interlinked.

Q67: 'Sweating in animals' is equivalent to what in plants?

Answer: Transpiration.

Q68: What factor contribute to rate of transpiration?

Answer:

Number of leaves

Number of stomata

Temperature of Surroundings

Wind

Water supply

Amount of Light

Q69: How does transpiration help plants?

Answer:

During transpiration the evaporating water carries away heat energy. Thus it cools the

temperature of plants.

Due to water loss, the osmotic pressure inside leaves decreases. Due to which water and

other mineral is able to reach leaves from roots and stem.

Following you tube video gives detailed explanation about Urinary System (Credits:

Introductory B. Timby and N. Smith)

Q70: Name the mineral required for healthy growth of teeth.

Answer: Calcium

Q71: Name the chemical used to detect presence of starch.

Answer: Iodine


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BHARATH COACHING CENTRE th 10 CBSE … cbse science … · growth, transport, synthesis, regulation, nutrition A. A butterfly sucking the nectar from the flowers in a garden. A butterfly