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Answers to RSPL/3
SECTION–A
1. DNA is called the ‘master copy’ in genetic because it is not directly involved in
the expression of genetic traits. It normally produces working copies in the form of
mRNAs, which then pass out into the cytoplasm to guide the synthesis of polypeptides.
2. There are four peptide chains in each antibody molecule. Antibody is classified into
five major types – IgA, IgG, IgD, IgE and IgM.
3. The revolutions related to the increase in the production of different food products
and the development of industries are:
White revolution – milk production
Green revolution – food grain production
Yellow revolution – oil seed production
Blue revolution – fish production
4. Citric Acid – Aspergillus niger
Butyric acid – Clostridium butylicum
5. International Union for Conservation of Nature and Natural Resources (IUCN)
(or world conservation union) was formed to conserve biodiversity. It keeps a list
of species which are facing extinction.
SECTION–B
6. The phenomenon is called pleiotropy.
Examples are:
(a) Sickle cell disease – Gene in homozygous recessive form (HbS HbS) effects not
only the RBCs which become sickle-shaped but also the numerous tissues in
the body. It may cause thrombosis, cardiac arrest or even renal failure. Thus,
gene shows multiple effects at different sites and is pleiotropic.
(b) Phenylketonuria – It occurs when the gene that codes for enzyme
phenylalanine hydroxylase suddenly mutates. This causes mental retardation,
reduced pigmentation of hair and skin in human.
(c)White eye colour mutation of Drosophila.
7.(a)DNA has a separate mechanism for repair, in case it has escaped proof reading
mechanism or damaged by uv rays.
A small cut is made at the point of repair by an enzyme endonuclease.
DNA polymerase-I removes the mismatched (or wrong) nucleotides, which is
replaced with the correct sequence of nucleotide. DNA-ligase then joins the
two ends to form one segment of DNA.
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(b)The distance between two consecutive base pair = 0.34 × 10–9 m
Given, length of DNA of bacteriophage lambda = 48502 × 0.34 × 10–9 m
= 16.49 × 10–6 m
8.(a) The college boy might be taking either sedative (barbiturates) or tranquillizers
(benzodiazepines).
(b) The person who consumes these tablets feels relaxed, drowsy and behaves calmly
in all circumstances because these sedatives depresses the brain activities and
blocks any kind of reaction till the effect of the sedative remains.
9. (a)(i) PER – Protein Efficiency Ratio (ii) RFLP – Restriction Fragment Length Polymorphism
(b) Sometimes, ELISA tests show false positive results while sometimes it fails to detect positivity. In these cases, it becomes difficult to detect the infection like
the presence of virus (HIV) and thus, the treatment for the disease gets delayed.
Or
(a)The two types of commonly used bioreactors are:
(i) Simple stirred-tank bioreactor
(ii) Sparged stirred-tank bioreactor
(b) The two basic types of fermentations are – batch and continuous fermentation.
(c) Simple stirred-tank bioreactor:
Advantages
Disadvantage
(i) Suitable for large-scale production The method is very expensive.
of micro-organism under required
controlled conditions.
(ii) Efficient transfer of air for better
growth of cells.
(any one)
Sparged stirred-tank bioreactor:
Advantages
Disadvantage
(i)S i m p l e d e s i g n a n d e a s y Needs more oxygen supply.
separation. No rotating part is
required.
(ii)Area and volume more in the
bioreactor. Since, the surface
area is more, oxygen supply is
increased with the help of the
bubbles.
(any one)
(any one bioreactors)
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10. Xerarch succession takes place in dry area and progresses from xeric to mesic
conditions. Hydrarch succession takes place in wet area and progresses from hydric
to mesic conditions.
When no organism live in newly formed lava or bare rocks, that area is called
primary succession. Primary succession is the first stage of ecological succession
followed by hydrarch or xerarch succession.
SECTION–C
11.(a) The flower that blooms once in 12 years is Neelakuranji (Strobilanthus kunthiana).
(b) Bryophyllum – Adventitious buds develop from the edges of the leaf.
Potato– buds develop from the potato tuber’s eye which give out shoots.
Rhizopus– Sporangia releases sporangiospores.
Penicillium– Conidia releases conidiospores.
(c)‘Amphibians of plant kingdom’ are mosses and liverworts. They need water
for the male gametes to swim and reach the female gametes for fertilization.
In absence of water, male gametes are unable to reach the female gametes.
Therefore, like frogs (which needs water for reproduction), they are also called
amphibians.
(d) Bisexual flowers are:
(a)China rose– Hibiscus rosasinensis
(b) Garden pea– Pisum sativum
Or
(a)
Pre-fertilization changes
Flowers have all the whorls– calyx
(sepals), corolla (petals), androecium
(male reproductive part), gynoecium
(female reproductive part).
Hormonal and structural changes
occur.
Flower buds develop where androecium and gynoecium become matured.
Post-fertilization changes
Sepals, petals and stamens are shed.
Zygote is formed by the fertilisation
of ovule that later forms the embryo.
Ovary becomes a fruit.
(any two)
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(b) Meiosis is the process of cell division where the chromosome numbers of
spores or gametes are reduced to half the number (Raploid) e.g. human has 46
chromosomes, sperms or ova, the chromosome number is reduced to 23.
Gametogenesis is the process of cell division where matured haploid gametes are
formed. Types of gametogenesis are – spermatogenesis and oogenesis. Gametes
are cells that takes part in sexual reproduction.
(c)Progeny from asexual reproduction are morphologically and genetically similar
to parents and they do not adapt well to climatic changes.
Sexually reproduced progeny are genetically different, non-identical to parents
and more adaptable to climatic changes.
12.(a) The two ways to prevent self-pollination in flowers are:
(i) Natural method
(ii) Artificial method
(i) Natural method – Some species release pollen grains before the stigma becomes
matured (protandry) or pistils become mature first before the dehiscence of
the anther (protogyny). Thus, the pollen grains are not able to fertilize the
ovule.
It may be noted, that there are some plants that are genetically self-incompetent
to produce offsprings. In these cases, they are multiplied artificially.
(ii) Artificial method – In this method, the males and the females of the same
flower or the same plant are not allowed to self-pollinate.
By this method, better plants (hybrids) with desired traits can be developed
specially for high yield, improved flower production and disease-resistant
crops.
(b)(i) Pericarp is a part of the fruit and acts as a protective layer.
(ii) Perisperm is a part of the seed (unused nucellus) and is usually non-functional.
Sometimes it becomes dry.
13.(a) Amniotic cavity is filled with a clear fluid called amniotic fluid that acts as a
protective cushion for the embryo and is a shock absorber.
(b) During lactation period (after parturition), menstrual cycle does not occur so the
chances of a woman to become pregnant are low. It is considered to be effective
for only 6 months after child birth. It is called lactational amenorrhea.
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(c) CuT is copper releasing IUD while LNG-20 is hormone releasing IUD.
Sperms are made immobile by the copper ions, released from CuT and thus also
effects the fertilizing capacity of sperms. The hormone released from LNG-20
makes the uterus unsuitable for implantation.
14.(a)Double helix structure of DNA consists of two long chain of nucleotides (or two
polynucleotide chains). These chains (or strands) are negatively charged due to
the presence of phosphate groups. The two strands of DNA are spirally coiled
and form DNA duplex. DNA (deoxy-ribonucleotide) is formed by three substances
- phosphate group (phosphoric acid H3PO4), deoxyribose sugar (C5H10O4) and
nitrogen base.
Nitrogenous bases are of two types– purines (adenine and guanine, common
in both DNA and RNA) and pyrimidines (cytosine and thymine in DNA while
cytosin and urasil in RNA). The two chains are joined by the hydrogen bonds
between the nitrogenous bases. Cytosine is joined to guanine on the opposite
side by three hydrogen bonds. Adenine is joined to thymine on the other side
by 2 hydrogen bonds.
Sugar and phosphate together forms the backbone of the DNA helix. In double
helix structure of DNA, the two chains run anti-parallel with polarity 5 → 3′
and 3′ → 5′.
(b) The theory that life originated from pre-existing life forms is termed as biogenesis.
15.
Goals for setting up Human Genome Project are:
(a)Determine the number and sequence of the base pairs in human genome.
(b) Genetic disorders are known only when various genes are identified.
(c) Functions of all genes are to be analyzed.
Applications and importance of HGP are:
(a)Tools and techniques for data analysis can be improved.
(b)Information can be stored in the form of databases that can be used later.
(Bioinformatics).
There has been immense debate about the project regarding issues like ethics, technological or practical utility (use or misuse).
Human cloning may lead to inbreeding dangers and also the number of homozygous
individuals with disorders may increase. There is also the danger of misuse of this
technology for individual’s benefit.
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16. Parents:
Round yellow seed
RRYY
Wrinkled green seed
×
rryy
Gametes:
RY × ry
F1 generation:
Round yellow
RrYy
DOMINANCE
On
selfing
RY
+
Gametes
RY
rY
rY
RrYy
rrYy
rrYy
RRyy
Rryy
ASSORTMENT
RrYy
RrYy
RrYy
INDEPENDENT
ry
RRYy
rrYY
RRYy
LAW OF
Ry
RrYY
RrYY
ry
Gametes
RRYY
Ry
F2 generation:
LAW OF
Rryy
rryy
Phenotypic ratio– Round yellow : Round green : Wrinkled yellow : Wrinkled green
Genotypic ratio– 1
9
:
2
:
:
3
2
:
3
:
:
1
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3
:
2
:
:
1
:
1
2
:
1
:
1
17. Human immune system: Human immune system consists of lymphoid organs,
tissues, cells and antibodies. Our immune system has two types of lymphocytesB-lymphocytes and T-lymphocytes.
Two types of lymphoid organs are:
(a) Primary lymphoid organs– bone marrow and thymus.
(b) Secondary lymphoid organs– Spleen, lymph nodes, tonsils, Peyer’s patches of
intestine and appendix.
The immune system plays a vital role in fighting against allergic reactions, auto
immune diseases and antigens.
Auto-immune disease:
For reasons, not exactly known (may be due to genetic factors), the body suddenly
attacks the self-cells resulting in body damages which is termed as auto-immune
disease.
e.g. Rheumatoid arthritis.
Immune system usually protects the body against bacteria and virus but in the
person with this disorder the body’s immune system instead attacks the joints. As a
result, there is joints inflammation causing a lot of pain to the person. Rheumatoid
arthritis generally affects the feet, hand, wrist, elbow and knee joints.
18.The important points that should be kept in mind before starting bee-keeping are:
(a)To know the nature and habits of bees.
(b) Management of beehives according to different seasons.
(c)The method of honey and beeswax collection.
Bees are good pollinators and they are used to pollinate flowers. Therefore, they are
grown in orchards to increase fruit and flower production. Bee inturn gets nectar from the flowers by which they can make honey. This increase the production of
honey. Thus, orchards are considered the best place for apiculture.
19. Indian Agricultural Research Institute developed the technology for biogas or gobar
gas production.
Biogas is a mixture of gases which mainly contains methane. Methanogenic bacteria
produce methane. Methanobacterium that grows on cellulose produces methane
(50-70%), CO2 (30-40%) and traces of N2, H2 and H2S by anaerobic respiration.
The calorific value of biogas is 23-28 MJ/m3.
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20. Bioreactors under good optimum conditions (like controlled pH, temperature,
vitamins, salt,oxygen) produce large quantities of biotechnological products. Raw
materials are converted to specific products by microbes, plants, animal cell or their
enzymes. After the desired product is formed, it has to undergo series of processes
like separation and purification before becoming a finished product for the market.
The products are also formulated with preservatives which undergoes drug test or
clinical trials for quality control. The whole process is called downstream processing.
21.
Competition
Predation
Parasitism
Rivalry between two or
more organisms to get
resources (food, water,
shelter) for their survival.
This interaction involves
carnivorous animals who
eat other animals (preys).
Generally the preys are
herbivorous animals (who
eat plants).
Interaction between two
organisms in which the
parasite survives on the
nutrition provided by the
host, and harms the host.
Mutualism
Amensalism
It may be of two types:
Intraspecific(when it is
between individuals of the e.g. tiger preys on deer.
same species)
e.g. lice (parasite) in
human (host).
Interspecific(when it is
between individuals of
different species)
e.g. Flamingoes and
resident fishes of a
lake compete for eating
zooplanktons.
Commensalism
Interaction between two
species where both live
peacefully and one is
benefitted while the other
is neither benefitted nor harmed.
Interaction between two
organisms of two different
species where both species
benefit each other. e.g.
Mycorrhizae– Here, algae
prepare food for fungus and
e.g. cattle egret(bird) and fungus provides protection
to algae.
grazing cattle.
Interaction between two
species where one destroys
the other while remaining
unaffected.
e.g. Staphylococcus growth
is restricted by Penicillium
growing in the same area.
22.(a) Importance of Carbon: Carbon is an important inorganic element and essential
component of protein, lipid, hormone,etc of the body and it needs to be available
in abundance in the environment.
Sources of carbon: Carbon dioxide in air, dissolved CO2 in water, fossil fuels,
carbonates and as graphite in rocks.
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Importance of phosphorus: Phosphorus is a major component of nucleic acids,
present in ATP and as phospholipid in the body. It is required in all metabolic
reactions to release energy from food where this energy is used up for various
body functions.
Sources of phosphorus: Phosphorus is present in the form of phosphate rocks,
is made available by water (aquatic) and soil(terrestrial) ecosystem. It is found
in combination with calcium, iron and aluminum.
(b) Scrubbers are of two types–dry and wet, e.g. wet scrubber is a device used to
remove gases like SO2 from the exhaust (like from thermal power plant). A
spray of water or lime medium is used and through which exhaust air is passed.
This water medium dissolves the gases, then lime reacts with SO2 to settle
down as precipitate of calcium sulphate or sulphite. Thus, it helps to reduce
air pollution.
SECTION–D
23.(a) Plucking of anthers from flower is called emasculation.
Putting polythene bags on flowers is called bagging, which is done to stop crosspollination.
The process of dusting desired pollen grains on the flowers for effective fertilization,
is termed as artificial hybridization.
(b) Gregor Johann Mendel is called the ‘Father of Genetics’.
The laws proposed by Mendel are
(i) Law of Dominance
(ii) Law of Segregation
(iii) Law of Independent Assortment
(c)The importance of learning genetics are:
(i) How to control the pre-existing inherited diseases/disorders by providing
proper health care solutions.
(ii) It also helps in understanding human beings better.
(iii) Traits and characteristics of an individual can be known and analyzed (using
tools) only when the concept of inheritance and genetics is well studied.
(iv) Studying human genetics means studying for the human welfare. In future,
it will help further in the development of health care through research and
in search of finding disease curing medicines.
(any two)
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SECTION–E
24.(a)
Chalaza
Outer integument
Inner integument
Nucellus
Antipodals
Embryo sac
Polar nuclei
Female gamete
Synergids
Micropyle
Hilum
Funiculus
Anatropous ovule
The purpose of reproduction are:
(i) To increase the population of a species, thus maintain its continuity.
(ii) Variation (due to cross-pollination) in the new generation may give rise to a
totally new species that might show higher rate of survival of the species.
(b)Features of reproduction are:
(i) Replication of DNA
(ii) Synthesis of cell organelles.
(iii) Cell division.
Or
(a)Dichogamy is the plant mechanism to prevent self-pollination in which anthers
and stigma mature at different times in a bisexual flower.
Herkogamy is the plant mechanism to prevent self-pollination and to promote
cross-pollination. It is done by providing spacial separation to the anthers and
stigma.
(b) Significance of seed formation:
(i) Reservoir of food for embryo’s nourishment during germination of seed.
(ii) It can be dispersed in new location to form new population of the species.
(iii) Hard seed coat protects the embryo inside the seed.
Significance of fruit formation:
(i) Fleshy part of the fruit helps in seed dispersal.
(ii) It is the source for many vitamins and minerals.
(iii) It protects the seed under unfavorable conditions.
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(c)Students can take some gram seeds, place them on a wet cotton pad over a
petri dish. If the seeds germinate after a 3-4 days, then the seeds are said to
be viable.
Viability is the ability of a seed to germinate after sometime, when suitable
conditions are provided to it.
25.
(a)
PCR
ELISA
(i)It is a method used for forensic (i)It is a method based on antigenstudy. DNA can be amplified
antibody interaction principle. It
and billion copies of it can be
is used to diagnose infections.
made within few hours (while in
bacteria it takes few days).
(ii)It is used to detect mutated (ii) Infection can be easily detected by
genes in cancer patients or used
antigen presence(may be protein,
to detect HIV in suspected AIDS
glycoprotein, etc) and antibodies
patients.
synthesis against the pathogens.
It is commonly used to diagnose
AIDS.
(b) Genetic defect caused by enzyme ADA (adenosine deaminase) deficiency is Severe
Combined Immune Deficiency (SCID).
This defect which effects the functioning of the immune system can be cured
by bone marrow transplant treatment or enzyme replacement therapy.
Enzyme replacement therapy: The patient is treated with a functional ADA
that breaks the toxic biological products and make it effective.
Gene Therapy: Retrovirus is used as a vector to create genetically engineered
lymphocytes. The patient’s bone marrow is then injected with these genetically
engineered lymphocytes. As the body cells die off after sometime, a patient
requires regular infusion of these lymphocytes.
Or
(a) The disadvantages of producing genetically modified crops are:
(i) Transgenic crops may endanger other crops.
(ii)These crops may cause allergies in human, this may often be a cause of
concern for human health.
(iii) They may be harmful for the environment.
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(any two)
(b)
Transgenic plant
Transgenic animal
Wheat/Maize/soya-bean (resistant to Mouse (carries gene for human growth
herbicide)
hormone hGH)
(c)The methods of producing transgenic organisms are:
(i) DNA microinjection
(ii) Retrovirus-mediated gene transfer
(iii) Embryonic stem cell-mediated gene transfer
(any two)
(d) Hypopituitarism: It is a condition when pituitary glands do not produce enough
hormone. One of the six hormones produced by pituitary gland is hGH. Deficiency
of hGH causes dwarfism. It may be detected by CT scan or MRI.
Hormone replacement therapy is the solution for this problem.
26.(a) Gause’s principle states that when two closely related species are present in
the same habitat who compete for the same resources, then only the dominant
species will survive while the inferior one will be eliminated as both cannot
co-exist at the same time. His principle is also called principle of competitive
exclusion.
e.g: In Galapagos islands, goats were introduced and it was found that within
10 years Abingdon tortoise almost became extinct as goats were found to be
better browsers.
e.g: In Galapogos Island, Darwin found 14 species of finches as they all had
developed different feeding habits.
(any one example)
Sometimes, competing species may co-exist due to their requirement of resources
at different feeding pattern or due to different specialization.
(b)Sometimes environmental conditions may be favourable or unfavourable for an
organism.The period of stress may be due to low or high temperature, excess
or lack of water, salt concentration differences or adverse pH etc. The graph
below shows the optimum levels of possible responses shown by organisms to
cope under stressful conditions– regulators, conformers and migrate and suspend
functioning possibilities.
Conformers
Internal level
Regulators
Partial
regulators
External level
Types of organismic response
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Most species maintain their own internal temperature to carry out its physiological
and biological activities. Despite drastic changes in the environmental conditions,
when an organism has the ability to maintain its own internal environmental
constant, it is termed as homeostasis.
Some organism that can maintain their physiological and biological functions
by regulating their internal homeostasis are called regulators. All mammals
and, birds maintain homeostasis by thermoregulation and osmoregulation.
99% of animals and plants are not able to maintain homeostasis and change
their body temperature according to the outside temperature, these are termed
as conformers.
Number of individuals added
15
(c)Birth rate =
=
= 0.5
30
Total number of individuals
Birth rate is 0.5 per year.
Or
The following points should be noted by the girl while making her project:
(a) Who developed the pyramids and why did he do so?
(b) Define the pyramids.
Describe the pyramids.
Give figures or make models of each pyramid.
(c) Importance and limitations of pyramids representation.
(a) Charles Elton developed the ecological pyramids. These ecological pyramids have
been developed and graphically represented so that the ecological parameters can
be studied.
(b)There are three ecological pyramids:
Pyramid of number– It represents the individuals number per unit area. The
producers are kept at the bottom while carnivores are at the top. It is an upright
pyramid with successive higher levels having less number of individual than the
lower level of the pyramid. Producers contain maximum number of individuals.
However, in parasitic food chain the pyramid of number is inverted.
Trophic level
Number of individuals
TC (Tertiary consumer)
3
SC (Secondary consumer)
354,000
PC (Primary consumer)
708,000
PP (Primary producer)
5,842,000
Pyramid of numbers in a grassland ecosystem
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Pyramid of biomass – It represents the biomass of consumers and producers
and their relationship. Producers are kept at the bottom while consumers at the
top level of the pyramid. This upright pyramid can be in inverted form for aquatic
ecosystem because in aquatic ecosystem it depends upon how much the organism
can reproduce and how long the members live.
Trophic level
Dry weight (kg m–2)
TC
1.5
SC
11
PC
37
PP
809
(a)
PC
21
PP
4
(b)
(a) Pyramid of biomass (b) Inverted pyramid of biomass
Pyramid of energy – It represents the amount of energy that is trapped per
unit area and time in different trophic levels. The producers are at the bottom
and consumers at the top of the pyramid. This upright pyramid that can never
be inverted as energy always flows from one level (generally higher to lower) to
another level (unidirectional) and part of the energy is lost at every level.
TC
10 J
SC
100 J
PC
1000 J
PP
10,000 J
1,000,000 J of sunlight
An ideal pyramid of energy
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(iii) Importance of ecological pyramid are:
The amount of solar energy trapped and efficiency of an ecosystem can be studied.
By this method, human beings gain thorough knowledge about conservation of
resources,how to maximize productivity and also to protect the ecosystem from pollution.
Limitations of ecological pyramid are:
It doesnot take into account the same species that belong to two or more trophic
levels.
Saprophytes have not been considered even though they play an important role in
the ecosystem.
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