CBSE 12TH BIOLOGY - Online Test
Q1. In human genome project, commonly used host were bacteria and yeast and their vectors are called as
Answer : Option B
Explaination / Solution:
YAC (Yeast artificial chromosome): It is a vector used to clone DNA fragments larger than 100 kb and up to 3000 kb. The major advantage of using artificial chromosomes such as YACs is that it can carry much larger DNA fragments than ordinary plasmids.
BAC (Bacterial artificial chromosome: It is an artificially constructed vector containing origin of replication & selectable marker for identification. It is capable of carrying large DNA fragments and can replicate easily inside a bacterial cell.
These vectors are used in human genome project for mapping or sequencing of genomes to be studied.
Q2. Which one is the most likely reason of not occurring regular menstrual cycle
Answer : Option A
Explaination / Solution:
Menstrual cycles get stopped during pregnancy. Sometimes it becomes irregular due to stress and other hormonal activities of the body.
Q3. Which of the following is not a factor that affects Hardy-Weinberg equilibrium?
Answer : Option B
Explaination / Solution:
Hardy-Weinberg equilibrium cannot be disturbed by vegetative propagation as the all new offspring are clone of each other having same gene. Migration, genetic drift, mutation and natural selection affect the equilibrium of alleles in a population.
Q4. Inability to conceive or produce children even after two years of unprotected sexual co-habitation is called
Answer : Option C
Explaination / Solution:
The inability to conceive even after two years of unprotected sexual co-habitation is called infertility. This may be due to not functioning of male or female reproductive system properly.
Q5. In rice genome project large insert genomic libraries used as the primary sequencing templates are constructed in
Answer : Option A
Explaination / Solution:
Rice genome sequencing is being conducted along the same lines as numerous other large-scale genome sequencing projects.
Large insert genomic libraries, used as the primary sequencing templates, are constructed in bacterial artificial chromosomes (BACs) or P1-derived artificial chromosomes (PACs).
Sequencing of the rice genome is being performed mainly from genomic BAC or PAC libraries created from the Nipponbare variety, which was chosen as the common template throughout the IRGSP.
Q6. The inner cell mass which have potency to give rise all tissue and organs is called
Answer : Option C
Explaination / Solution:
The inner cell mass (embryo) contains certain cells called stem cells that have capability to give rise to all tissues or organ in adult.
Q7. Founder effect is the
Answer : Option C
Explaination / Solution:
The founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.
Sometimes the change in frequency is so different in the new sample of population that they become a different species. The original drifted population becomes founders.
Q8. Amniocentesis is a method to
Answer : Option D
Explaination / Solution:
Amniocentesis is a method to known the chromosome type of the foetus. It is used to detect the genetic disorder of foetus by analyzing chromosome. It is misused to known the sex of foetus.
Q9. Repetitive DNA sequence shows high degree of polymorphism that forms the basis of
Answer : Option D
Explaination / Solution:
The term DNA fingerprinting - or genetic fingerprinting - is applied to the scientific process whereby samples of DNA are collected, collated and used to match other samples of DNA, which may have been found at the scene of a crime.
DNA fingerprinting works on the basis that each individual's DNA structure - or genetic make-up - is unique and therefore cannot be forged, faked or altered in any way.
One of the most common DNA fingerprinting procedures is RFLP: Restriction Fragment Length Polymorphism. Special enzymes are used to cut segments of a sample from which DNA is extracted. The procedure of RFLP focuses on repetitious sequences of DNA 'bases' which vary greatly from individual to individual.
Q10. Shortest phase of the menstrual cycle is
Answer : Option B
Explaination / Solution:
Menstrual cycle is divided into several phase starting from menses during which endometrium breaks and comes out through vagina for 4 to 5 days. Ovulatory phase occurs in the middle of menstrual cycle (14/15th day) during which egg is released.
