plzz send photos of biology paper 12th only 2018-19 any states
Answers
(Functions of the parts labelled )
Expand VNTR and describe its role in DNA fingerprinting.
List any two applications of DNA fingerprinting technique.
Ans.
VNTR - Variable Number of Tandem Repeat(s)
- used as a probe (because of its high degree of polymorphism)
Forensic science / criminal investigation (any point related to forensic science) /determine population and genetic diversities / paternity testing / maternity testing/ study of evolutionary biology (Any two)
Differentiate between Parthenocarpy and Parthenogenesis. Give one example of each.
Ans.
Parthenocarpy Parthenogenesis
Formation of fruit without fertilization New organism develops without fertilization
e.g. banana / grapes / any other e.g. Drones /male honey bee / turkey / correct example rotifers / some lizards / any other correct example
Medically it is advised to all young mothers that breastfeeding is the best for their newborn babies. Do you agree ? Give reasons in support of your answer.
Ans. Yes = 1 ,provides nutrition (calcium , fats , lactose ) / provides (passive) immunity / provides antibodies / Ig A (Any two)
Explain the mechanism of ‘sex determination’ in birds. How does it differ from that of human beings?
Ans. In birds;
Birds : female heterogamety / female produces (Z) type and (W) type of gametes
Humans : male heterogamety / male produces (X) type and (Y) type of gametes
How has the development of bioreactor helped in biotechnology?
Name the most commonly used bioreactor and describe its working.
Ans.
Larger biomass / large volume of culture can be processed leading to higher yields of desired specific products (protein / enzymes) , under controlled condition
Stirring type
- Mixing of reactor contents evenly (with agitator system or a stirrer)
- Facilitates oxygen availability
- Temperature / pH / foam control // under optimum conditions
Explain the roles of the following with the help of an example each in recombinant DNA technology:
Restriction Enzymes
Plasmids
Ans.
It recognises a specific sequence of base pairs / pallindromes, and cuts the DNA strand at a specific site
eg. EcoRI / Hind II or any other correct example
Act as vectors / cloning of desired alien gene / foreign gene eg. pBR322 / plasmid of Salmonella / plasmid of Agrobacterium / Ti Plasmid /Tumour inducing Plasmid
Explain out-breeding, out-crossing and cross-breeding practices in animal husbandry.
Ans. Out breeding – Breeding of unrelated animals (which may be between individual of same breed or between individuals of different species)
Out crossing – (a kind of out breeding) Mating of animals within the same breed but having no common ancestors on either side of their pedigree upto 4 –6 generations
Cross breeding – (another type of out breeding) Superior males of one breed are mated with superior females of another breed
Organic farmers prefer biological control of diseases and pests to the use of chemicals for the same purpose. Justify.
Give an example of a bacterium, a fungus and an insect that are used as biocontrol agents.
Ans.
- Reduces dependence on toxic chemicals
- Protects our ecosystem or environment
- Protects and conserves non-target organisms / they are species - specific
- These chemicals being non-biodegradable may pollute the environment permanently
- These chemicals being non-biodegradable may cause biomagnification
Bacteria – Bacillus thuringiensis
Fungus – Trichoderma
Insect – Ladybird / Dragonfly / Moth or any other correct example
Differentiate between analogous and homologous structures.
Select and write analogous structures from the list given below :
Wings of butterfly and birds
Vertebrate hearts
Tendrils of bougainvillea and cucurbita
Tubers of sweet potato and potato
Ans.
Analogous - Anatomically not similar though perform similar functions / are a result of convergent evolution
Homologus - Anatomically similar (but perform different functions) / are a result of divergent evolution
Option (i) Wings of butterfly and birds / (iv) Tubers of sweet potato and potato