Biology set 1 2018-2019 HSC Science (General) 12th Board Exam Question Paper Solution

As the base sequence present on one strand of.DNA decides the base sequence of other strand, this strand is considered as __________

Descending strand

Leading strand

Lagging strand

Complimentary strand

________ shows haplo-diploid type of sex-determination.

Pigeon

Honey bee

Parrot

Snake

Membrane bound receptors and hormones produce second messengers like _________.

Renin

IP₃

ANF

GHRF

During double fertilization second male gamete fuses with ___________.

antipodal cell

egg cell

secondary nucleus

synergidsv

What is Sinus arrhythmias?

By which process ammonia is converted into urea in liver?

Give the role of Plasmids in bacterial cell.

A person is showing symptoms like increased BMR, heart rate, pulse rate, blood pressure and deposition of fats in eye sockets. Name the disease he is suffering from.

Define apiculture. Name the products obtained from it.

Define biofertilizers. Give two types of fungal biofertilizers

Give the types of blood proteins and human hormone’s produced by recombinant DNA-technique

Write any two scientific and commercial values of transgenic animals in favour of human being.

Define ‘Respiratory Quotient’ (RQ) and calculate the Respiratory Quotient for Carbohydrate.

Light and dark reactions are interdependant Explain.

Classify the chromosomes on the basis of position of centromere.

Sketch and label structure of male gametophyte in angiosperm. What is Siphonogamy?

Complete the following chart and rewrite.

                                       (Or)

Explain outbreeding devices in angiospermic plants.

What is Biofortification? Explain selective breeding with suitable example.

In the light of Griffith’s experiment, explain the action of two stains of Diplococcus pneumoniae and give his conclusion.

Give scientific reasons:
(A) The pyramid of enegy is always upright.
(B) In an ecosystem the energy flow is always unidirectional.
(C) Ozone present in the stratosphere is called as “good ozone”.

Define ‘reproductive isolation’ and explain two types of reproductive isolation.

Name the connecting link between glycolysis and TCA cycle and explain it.

Explain internal structure of kidney with the help of suitable diagram.

Explain the mechanism of reflex action with the help of a suitable diagram.

Define pollution. “Industries are pouring poison in water” - Explain

With the help of a suitable diagram, describe Ultra structure of the cell organalle, which is essential for photosynthesis.

                                        (OR)

During photosynthesis “O2 is evolved from water molecule and not from CO2”. Give the experimental proof given by Robert Hill.

Explain with the help of a suitable diagram conducting system of human heart.

                                (OR)

Give reasons :
(1) Lymphatic vessels are milky in appearance.
(2) Monocytes are called scavengers.
(3) The wall of left ventricle is thicker than right ventricle.
(4) Valves are present in the veins.
(5) Pulmonary veins carry oxygenated blood.

Which phoenomenon gives 2 : 1 ratio instead of 3 : 1 ratio? Describe with graphical representation.

                                             (OR)

A pea plant homozygous for yellow round seed is crossed with its recessive parents. Calculate the phenotypic and genotypic ratio with the help of checker board.

After puberty human female shows cyclic changes in her reproductive system. Explain structural and hormonal changes in the uterus.

                                      (OR)

Give reasons :
(1) Scrotal sac serves as thermoregulator.
(2) Corpus luteum gets converted into corpus albicans in absence of fertilization.
(3) Missing of menses is the first indication of pregnancy.
(4) Surgical sterilization is a permanent method of birth control. (5) Human egg is microlecithal.