These are the solutions of chapter 5 Life Processes of class 10 science of RBSE (Rajasthan education board). These solutions have been prepared by experienced teachers.
.jpg "RBSE Solutions for Class10 Science Chapter 5 Life Processes")
If you
are preparing for RBSE class 10 board exams, then these solutions of intext and
end exercise questions will help you a lot.
These
solutions cover a complete syllabus and
will let you solve homework and assignments in an easy way.
Life Processes
|
Board |
RBSE |
|
Subject |
Science |
|
Chapter |
Life Processes |
|
No. of Intext questions |
21 |
|
No. of End exercise questions |
13 |
|
Prescribed Book |
NCERT Science |
Answers of Questions on Page 81
Q.1Why is
diffusion insufficient to meet the oxygen requirements of multi-cellular
organisms like us?
Answer
Multicellular organisms such as
humans possess complex body designs. All
the body cells are not in direct contact with the surrounding environment. They
have specialised cells and
tissues for performing various necessary functions of the body Therefore, every
cell of the body will not get oxygen as per need by the process of diffusion
from the environment. Therefore diffusion is insufficient to meet the oxygen
requirements of multicellular organisms.
Q.2What
criteria do we use to decide whether something is alive?
Answer
The criteria of molecular movement is
used to decide whether something is alive. Living beings also show
growth and movement
Q.3What are
outside raw materials used for by an organism?
Answer
An
organism uses outside raw materials mostly in the form of food and oxygen.Life
on earth depends on carbon based molecules. So carbon based raw materials are
used by an organism.The raw materials required by an organism can
be quite varied depending on the complexity of the organism and its
environment.
Q.4 What
processes would you consider essential for maintaining life.
Answer
Life processes such as
nutrition, respiration, transportation, excretion, etc. are essential for maintaining life.
Answers of Questions on page 87
Q.1What are
the differences between autotrophic nutrition and heterotrophic nutrition?
Answer
|
Autotrophic nutrition |
Heterotrophic nutrition |
|
(i).They can synthesise food from simple inorganic
raw materials such as carbon di oxide and water. |
(i).They get food directly or indirectly from autotrophs. This food is
broken down with the help of enzymes. |
|
(ii).Presence of green pigment (chlorophyll) is
necessary. |
(ii).No pigment is required in this type of nutrition. |
|
(iii).Food is generally prepared during day time |
(iii) Food can be prepared at all times |
Q.2Where do the
plants get each of the raw materials and photosynthesis?
Answer
Photosynthesis in plants requires
following raw materials -The raw
material carbon di oxide enters from the atmosphere through stomata.Water is
absorbed from the soil by the plant roots.Sunlight, is essential component to
manufacture food, is absorbed by the chlorophyll and other green parts of the
plants.
Q.3What is the
role of the acid in our stomach?
Answer
Gastric glands present in the wall of
stomach release hydrochloric acid. It performs the following two functions.
Hydrochloric acid is released in stomach and provide acidic medium. Enzyme
pepsin digests protein and this enzyme acts in acidic medium only. The harmful
germs (pathogens) coming with food, are also killed by hydrochloric acid.
Q.4What is the
function of digestive enzymes?
Answer
Digestive enzymes break complex food
materials into simpler molecules. Enzymes
such as amylase, lipase, pepsin, trypsin, etc. help in the breaking down of complex food particles into
simple ones Proteins are converted to amino acids,
fats into fatty acids and complex carbohydrates into glucose.
Q.5How is the
small intestine designed to absorb the digested food?
Answer
The
small intestine has millions of tiny finger-like projections called villi. So the surface area for absorption is
increased many times. Many blood vessels are present in villi that
absorb the digested food and carry it to the blood stream. From the blood
stream, the absorbed food is delivered to each and every cell of the body.
Answers of Questions on page 91
Q.1What
advantage over an aquatic organism does a terrestrial organism have with
regards to obtaining oxygen for respiration?
Answer
Terrestrial
organisms take up oxygen from the air whereas aquatic animals need to utilize oxygen present in the
water. . Since the content of oxygen in air is high, the terrestrial animals do
not have to breathe faster to get more oxygen. On the other hand aquatic
organisms take oxygen dissolved in water and amount of oxygen in water is very
low. Aquatic animals spend more energy
than terrestrial animals.
Q.2What are
the different ways in which glucose is oxidized to provide energy in various
organisms?
Answer
At first Glucose is broken down in the cell cytoplasm into a
three carbon molecule called pyruvate.
Pyruvate is further broken down by different ways to provide energy.
The breakdown of glucose by different pathways can be illustrated as
follows.
Q.3How oxygen
and carbon dioxide are transported in human beings?
Answer
In human beings, oxygen and carbon di
oxide are transported in the following ways-
Haemoglobin transports oxygen
molecule to all the body cells for cellular respiration. The haemoglobin pigment present in the blood gets attached to
oxygen molecules and form
oxyhaemoglobin. This oxygenated blood is then distributed to all the
body cells by the heart. Carbon di oxide is soluble in water so most of the
carbon di oxide produced during respiration is transported in dissolved form in
blood through lungs.
Q.4How are
lungs designed in human beings to maximize the area for exchange of gases?
Answer
In human beings, to maximize the area
for exchange of gases, inner surface of lungs has smaller and smaller tubes
that finally terminate into balloon like structures which are called alveoli. Thus, alveoli are the site for exchange of gases. The
walls of alveoli have extensive network of blood-vessels(capillaries). Each lung contains millions of alveoli. These
numerous alveoli increase the surface area for gaseous exchange making the
process of respiration more efficient. The lungs get filled up with air during
the process of inhalation as ribs are lifted up and diaphragm is flattened. The
air that is rushed inside the lungs fills the numerous alveoli present in the
lungs.
Answers of Questions on page 96
Q.1What
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 as follows:
(i)Blood
(ii)Blood vessels
(iii)Heart
Functions
(i)Blood:- It is a fluid
connective tissue and blood helps in the transport of oxygen, nutrients, CO2,
and nitrogenous wastes.
(ii)Blood Vessels :- The blood
vessels are two types : arteries and veins. Arteries carry blood from heart to
different organs of the body and veins bring blood back to the heart.
(iii)Heart. It is a muscular
organ which pumps oxygenated blood into arteries and receives deoxygenated
blood from the different body organs through veins.
Q.2Why
is it necessary to separate oxygenated and deoxygenated blood in mammals and
birds?
Answer
Warm-blooded animals such
as birds and mammals maintain a constant body temperature. So these animals
require more oxygen (O2) for more cellular respiration so that they can produce
more energy to maintain their body temperature. It is necessary to separate
oxygenated and deoxygenated blood in mammals and birds, because they need high
energy quantity and large amount of oxygen. Separation of oxygenated and
deoxygenated blood provides high oxygen supply to the organs.
Q.3What
are the components for the transport system in highly organised plants?
Answer
The components of the
transport system in highly organized plants are as follows:
(i)Xylem (ii).
Phloem
(i)Xylem conducts water and
minerals absorbed by roots to different parts of the plant.
(ii)Phloem conducts prepared
food from leaves to the different parts of the plant.
Q.4How
are water and minerals transported in plants?
Answer
Horizontal transpiration
plays an important role in the transportation of water and minerals in plants.
The components of xylem tissue (tracheids and vessels) of roots, stems, and
leaves are interconnected to form a continuous system of water-conducting
channels that reaches all parts of the plant. Transpiration creates a suction
pressure, as a result of which water is forced into the xylem cells of the
roots. The root hairs are unicellular and in contact with soil and water. These root hairs absorb water and mineral.
Transpiration from the leaves maintain a steady column of water from roots to
leaves. Then there is a steady movement of water from the root xylem to all the
plant parts through the interconnected water-conducting channels.
Q.5How
is food transported in plants?
Answer
Food is prepared in green leaves of plant. Food is supplied to all parts of plants and this transportation is conducted by Phloem. Phloem transports food materials from the leaves to different parts of the plant body. The transportation of food in phloem is achieved by utilizing energy from ATP. As a result of this, the osmotic pressure in the tissue increases causing water to move into it. Food molecules enter the phloem cells and transported upward and downward. This movement of food is known as translocation.
Answers
of Questions on page 98
Q.1Describe
the structure and functioning of nephrons.
Function
– The circulatory system has nutrients
aswellas waste materials. The arteriole
entering into Bowman’s capsule has larger diameter while arteriole coming out
has a small diameter. The pressure is inside the glomerulus is increased and
wastes as well as useful substances are filtered off. This is called initial
filtration. Glucose, amino acids, salts and water are selectively re absorbed
as the urine flows along the tube. Now the urine is sent to urinary bladder through
ureter.
Q.2What are
the methods used by plants to get rid of excreting products?
Answer
Plants have no excretory organs. They
use following methods-
Resins, Latex and other materials are
excluded from lenticels.
Exchange of gases takes place by stomata
in leaves.
Dead tissues are stored in cork, bark etc.
Excess water is transpired by leaves.
Q.3How the
amount of urine is produced regulated?
Answer
The amount of urine produced depends on the amount of excess water and dissolved wastes present in the body. About 180 litres of fluid is collected in nephrons daily but most of the water is re- absorbed by the tubule.The urine enters a long tube, called ureter which moves upto urinary bladder. Urine is stored in it and it is passed out when needed.
Answers of Exercise Questions
Q.1The kidneys
in human beings are a part of the system for
(a)nutrition
(brespiration
(c)excretion
(d)transportation
Answer (c)excretion
Q.2Xylem in
plants are responsible for
(a)transport of water
(b)transport
of food
(c)transport of amino acids
(d)transport of oxygen
Answer (a)transport
of water
Q.3The
autotrophic mode of nutrition requires
(a)carbon dioxide and water
(b)chlorophyll
(c)Sunlight
(d)all
of the above
Answer (c)all
of the above
Q.4The
breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a)Cytoplasm
(b)mitochondria
(c)Chloroplast
(d)nucleus
Answer (c)mitochondria
Q.5How are
fats digested in our body? Where this process does takes place?
Answer
Digestion of fats takes place in small
intestine. Fats are present in the form of large globules in the small
intestine. The small intestine gets
the secretions in the form of bile juice and pancreatic juice respectively from
the liver and the pancreas. The digestion of fats completes in the following
steps:
Bile salts break larger globules into
smaller globules. Pancreatic juice secreted by pancreas has enzyme lipase which
breaks down emulsified fats. Enzymes secreted from the walls of small intestine
finally convert fats into fatty acids.
Q.6What is
role of saliva in the digestion of food?
Answer
Saliva is watery fluid which contains
salivary amylase enzyme and mucous. Saliva plays the following role in the
digestion of food. Saliva moistens and softens the food for the smooth passage.
Saliva contains enzyme amylase which is also called ptyalin which breaks down
starch (a complex molecule) to maltose a (a simple molecule of sugar).
Salivary amylase
Starch---------------------------→ Maltose
Q.7What are
the necessary conditions for autotrophic nutrition and what are its byproducts?
Answer
The necessary conditions for
autotrophic nutrition are as follow:
(i). Chlorophyll
(ii)Water
(iii) Carbon dioxide
(iv)Sunlight
oxygen is its
byproduct.
Q.8What are
the differences between aerobic and anaerobic respiration? Name some organisms
that use the anaerobic mode of respiration.
Answer
|
Aerobic respiration |
Anaerobic respiration |
|
It occurs in the presence of O2. |
It
occurs in the absence of O2. |
|
Exchange of gases takes place. |
Exchange
of gases is absent. |
|
It occurs in cytoplasm and mitochondria. |
It
occurs only in cytoplasm. |
|
Glucose is completely oxidized into carbon di oxide,
water and energy. |
Glucose
is oxidized into lactic acid and ethyl alcohol.
|
|
It yields 36 ATPs. |
It
yields only 2 ATPs. |
Q.9How are the
alveoli designed to maximize the exchange of gases?
Answer
The alveoli are the small balloon-like structures present in the lungs which maximize the area for exchange of gases. The walls of alveoli have extensive network of blood-vessels. Each lung contains 300−350 million alveoli. This large surface area makes the gaseous exchange more efficient.
Q.10What would
be the consequences of a deficiency of hemoglobin in our body?
Answer
Haemoglobin
is the respiratory pigment that transports oxygen to the body cells for cellular respiration. Deficiency
of hemoglobin in our body will affect the supply of oxygen to tissues and
cells. It can also lead to a disease called anaemia.It
will result into short breath, tiredness in doing hard work etc.
Q.11Describe
double circulation in human beings. Why is it necessary?
Answer
The
blood flows twice through the heart in each cardiac cycle. From body parts
deoxygenated blood is taken to right atrium and right ventricle. When right
ventricle contracts, the blood is taken to lungs by Pulmonary artery. Now
oxygenated blood is taken by Pulmonary vein to left atrium and left ventricle.
When left ventricle contracts, the blood is distributed to all body parts.so
the blood flows two times in one cardiac cycle, this known as ‘Double circulation’.
Importance of
double circulation:
Double circulation keeps the oxygenated and
deoxygenated blood separated so that the blood does not get mixed. This allows
highly efficient supply of oxygen to all body parts and cells. Warm blooded
animals like human and birds have to maintain constant body temperature so they
need more oxygen to maintain body temperature, double circulation allows more
supply of oxygen to body parts.
.jpg "Importance of double circulation")
12What are the
differences between the transport of materials in xylem and phloem?
Answer
Difference between transport of
materials in xylem and phloem
|
Xylem |
Phloem |
|
(i).Xylem
tissue helps in the minerals. |
(i)Food
prepared by leaves in transported by phloem. |
|
(ii).Transportation
is in upward direction.
|
(ii)Transportation
is from leaves to other parts such as roots, fruits and seeds. |
|
(iii).It
largely takes place using simple physical forces like transpiration. |
(iii)It
is achieved using energy in the form of ATP |
Q.13 Compare the functioning of alveoli in the lungs and
nephrons in the kidneys with respect to their structure and functioning.
Answer
|
Alveoli |
Nephron |
|
(i).Alveoli
are balloon like structure at the end of fine tubes of lungs. |
(i).Nephrons
are the tubular structures present in the kidneys |
|
(ii).Alveoli
are the unit of respiratory system. |
(ii).Nephron
is the unit of excretory system. |
|
(iii).The
walls of the alveoli are one cell thick and it contains an extensive network
of blood Capillaries. |
(iii).Nephrons
are made of glomerulus, bowman’s capsule, and a long renal tube. It also
contains a cluster of thin-walled Capillaries. |
|
(iv).In
alveoli exchange of gases takes place. |
(iv).In
nephrons, waste products are filtered and selective re-absorption of some
molecules takes place. |
Related Topics
Chapter | Chapter Name |
1 | |
2 | |
3 | |
4 | |
5 | |
6 | |
7 | |
8 | Heredity |
9 | Light – Reflection and Refraction |
10 | The Human Eye and the Colourful World |
11 | Electricity |
12 | Magnetic Effects of Electric Current |
13 | Our Environment |
.jpg)
.jpg)
.jpg)
No comments:
Post a Comment