CBSE 12TH BIOLOGY - Online Test
Q1. Which one is used for knowing whether or not a population is evolving?
Answer : Option D
Explaination / Solution:
Hardy-Weinberg equation is used to knowing whether or not a population is evolving or not. This equation is represented as
In the equation, p2 represents the frequency of the homozygous genotype AA, q2 represents the frequency of the homozygous genotype aa, and 2pq represents the frequency of the heterozygous genotype Aa.
Q2.
Assertion: The surgical procedure in man to block gametes transport to prevent conception is called tubectomy.
Reason: Tubectomy is cutting and tieding of fallopian tube to prevent release of ovum.
Answer : Option D
Explaination / Solution:
The surgical procedure in man to block gametes transport to prevent conception is called vescetomy as vas deference is cut and tied. Tubectomy is cutting and tieding of fallopian tube to prevent release of ovum from ovary.
Q3. The genetic and physical maps on genome was generated using information on
Answer : Option A
Explaination / Solution:
The sequence of chromosome 1 was completed only in May 2006 (this was the last of the 24 human chromosomes – 22 autosomes and X and Y – to be sequenced).
The challenging task was assigning the genetic and physical maps on the genome. This was generated using information on polymorphism of restriction endonuclease recognition sites, and some repetitive DNA sequences known as microsatellites.
Q4. Two hormones that regulate the menstrual cycle are
Answer : Option A
Explaination / Solution:
Menstrual cycle is controlled by two hormones estrogen and progesterone. Level of estrogen hormone increase sharply during ovulation and progesterone level increase during secretory phase.
Q5. Tendrils in plants are an example of
Answer : Option B
Explaination / Solution:
Convergent evolution is different structures evolving for the same function and hence having similarity. Analogous organs are example of convergent evolution. Tendril of plants is example of these kinds of evolution.
Q6.
Which is true about uses of contraceptive methods?
a. They are practiced against natural reproductive events.
b. They are used to prevent pregnancy or to delay or space pregnancy.
c. Uses of these methods may cause nausea, abdominal pain, irregular menstrual bleeding etc.
Answer : Option D
Explaination / Solution:
Contraceptive methods are practiced against natural reproductive events. They are generally used to prevent unwanted pregnancy or space between pregnancy. Use of contraceptive methods may cause nausea, abdominal pain, irregular menstrual bleeding etc.
Q7. Single nucleotide polymorphism (SNPs) revolutionize the process of finding chromosomal locations for
Answer : Option C
Explaination / Solution:
Scientists have identified about 1.4 million locations where single base DNA differences (SNPs) occur in human. This information is helpful in finding chromosomal locations for disease-associated sequences and human history.
Q8. The secretory phase of in the human menstrual cycle is called as
Answer : Option A
Explaination / Solution:
Menstrual cycle is divided into three phases menstruation phase, follicular phase or proliferative phase and luteal phase or secretory phase.
Q9. Disturbance in genetic equilibrium or Hardy-Weinberg equilibrium in a population is due to
Answer : Option C
Explaination / Solution:
Disturbance in genetic equilibrium in a population is due to evolution. Evolution occurs due to variation and natural selection. Variation is due to change in alleles.
Q10. Statement I: Ideal contraceptive should be easily available, effective and reversible without no or least side effects.
Statement II: Condom is a barrier method of contraception that prevents from HIV infection also.
Statement III: Surgical method of contraception is reversible.
Statement II: Condom is a barrier method of contraception that prevents from HIV infection also.
Statement III: Surgical method of contraception is reversible.
Answer : Option A
Explaination / Solution:
Ideal contraceptive should be easily available, effective and reversible without or least side effects. Condom is used to prevent unwanted pregnancy along with prevention against HIV infection. Surgical method of contraception is irreversible.
