Category: Class 12 Biology Objective Questions

Biology Multiple Choice Questions on “Flowering Plants Reproduction – Pollen-Pistil Interaction”.

1. Pollen–pistil interaction determines the ____ of the pollen.
a) compatibility
b) color
c) nature
d) maturation
Answer: a
Clarification: Pollen-pistil interaction determines the suitability of pollen for carrying out the process of sexual reproduction. If it is not compatible, fertilization process will not begin.

2. _____ incompatibility prevents cross pollination.
a) Intraspecific
b) Self
c) Interspecific
d) Outbreeding
Answer: c
Clarification: Interspecific incompatibility prevents cross pollination between members of different of different species. It maintains species individuality.

3. ______ incompatibility promotes cross pollination.
a) Inbreeding
b) Intraspecific
c) Outbreeding
d) Interspecific
Answer: b
Clarification: Intraspecific incompatibility promotes cross pollination and ensures heterozygosity which helps in evolution. It is achieved by self-sterility. It is also called self-incompatibility.

4. In ______ self incompatibility, genotype of pollen determines the incompatibility.
a) outbreeding
b) interspecific
c) sporophytic
d) gametophytic
Answer: d
Clarification: In gametophytic self-incompatibility, genotype of pollen determines the incompatibility. Pollen is compatible with the diploid cell of that pistil that carries the S allele other than the one present on the pollen.

5. In ______ self incompatibility, genotype of pollen does not determine the incompatibility.
a) intraspecific
b) inbreeding
c) sporophytic
d) gametophytic
Answer: c
Clarification: In sporophytic self-incompatibility, genotype of sporophytic tissues and not the pollen, determines the incompatibility. Seen in Asteraceae and Brassicceae.

6. Pollination guarantees the transfer of the right type of pollen.
a) True
b) False
Answer: b
Clarification: There is no guarantee that compatible pollens will fall on the stigma since pollination highly depends on factors like wind, animals, birds, insects, etc.

7. How is the dialogue of pollen rejection maintained in the pistil?
a) Stigma
b) Nucellus
c) Chemicals
d) Style
Answer: c
Clarification: Pistil has the power of recognizing the pollen. If the pollen is incompatible with the pistil, the pistil will not allow the growth of the pollen tube and mediate the process via chemicals, just like hormones.

8. There are ____ present on the stigmatic surface.
a) vitamins
b) proteins
c) polysaccharides
d) disaccharides
Answer: b
Clarification: In the recent years, botanists have found out the presence of certain proteins present on the pollen and the stigma that helps in the recognition.

9. It is necessary for the stigma to recognize the pollen before the process of fertilization.
a) False
b) True
Answer: b
Clarification: It is necessary for the stigma to recognize the pollen. Not all plant species are compatible with each other and in some species its not compatible with its own self.

10. ____ does not allow the raising of pure lines.
a) Self compatibility
b) Interspecific incompatibility
c) Intraspecific incompatibility
d) Outbreeding
Answer: c
Clarification: The disadvantage of intraspecific incompatibility also known as self-incompatibility is that it does not allow the production of pure lines. It only promotes cross pollination.

Biology Multiple Choice Questions on “Menstrual Cycle – 1”.

1. Primate female reproductive cycle is called ________
a) menstrual cycle
b) water cycle
c) blood cycle
d) ovarian cycle
Answer: a
Clarification: Mammals exhibit an estrous cycle wherein if the egg is left unfertilized the endometrium is resorbed. In primates like humans, however, the endometrium is shed. This cycle unique to very few mammalian species is called as the menstrual cycle.

2. The first menstrual flow is called as ___________
a) Menopause
b) Menstruation
c) Menarche
d) Ovulation
Answer: c
Clarification: The first menstruation occurs during puberty in humans. This menstrual is called menarche, which means the onset of menstruation and hence the ability to get fertilized.

3. The menstrual cycle in humans lasts for a lunar month.
a) True
b) False
Answer: a
Clarification: Menstruation occurs in all primates. It varies across species lasting from days to months. In humans, it lasts approximately for a lunar month i.e., 28-29 days.

4. Ovulation occurs at the onset of the menstrual cycle.
a) True
b) False
Answer: b
Clarification: The menstrual cycle is timed from the day of bleed to the day before the next bleed. Ovulation or release of egg happens on 14th to 15th day of the menstrual cycle.

5. The onset of the menstrual cycle is characterized by a discharge of blood and tissue matter from the uterus. What is this discharge termed as?
a) Egg
b) Menarche
c) Menses
d) Ovulation
Answer: c
Clarification: Menses is the shedding of the endometrial lining along with the unfertilized egg. Thus it is composed of blood and tissue discharge. It lasts for 3-5 days.

6. What layer of the uterus is shredded during menstruation?
a) Perimetrium
b) Myometrium
c) Epimetrium
d) Endometrium
Answer: d
Clarification: Uterus is composed of three layers of tissues. The outer perimetrium holds uterus in shape. The middle myometrium is responsible for contractions while the innermost endometrium is the layer that holds the egg. During menstruation, the inner layer is shredded off along with the egg and the supplying blood vessels.

7. Which of the following can lead to a menstrual cycle?
a) Fertilization of egg
b) Unfertilized egg
c) Improper sleep
d) Study pressure
Answer: b
Clarification: The menstrual cycle is a natural phenomenon. It arises as the unfertilized egg needs to be released along with the thick endometrium that was formed in anticipation of the would-be embryo.

8. Which of the following will not result in a miss in the menstrual cycle?
a) Fertilization of the egg
b) Anxiety and stress
c) Bad health
d) Gyming
Answer: d
Clarification: Menstrual cycle occurs as a result of the need to remove the unfertilized egg. Thus if egg is fertilized, the menstrual cycle is skipped. However, other factors like bad health, anxiety, and stress, etc. can also lead to improper body rhythm and thus a miss in the menstrual cycle. Gyming and exercise are healthy habits and keeps your body in check. Thus won’t affect your body rhythm.

9. The phase during which menses occur is called _______
a) primary phase
b) follicular phase
c) menstrual phase
d) luteal phase
Answer: c
Clarification: The menstrual cycle begins with release of blood and mucus. This discharge is called menses. This phase of the menstrual cycle is hence called the menstrual phase.

10. The follicular phase is also called as __________
a) menstrual phase
b) luteal phase
c) proliferative phase
d) secretory phase
Answer: c
Clarification: The follicular phase follows the menstrual phase. It is characterized by the maturation of primary follicles to Graafian follicles. Since there is a lot of growth around the developing egg cell, it is called the proliferative phase.

11. During what phase of menstrual cycle are primary follicles converted to Graafian follicles?
a) Menstrual phase
b) Follicular phase
c) Luteal phase
d) Secretory phase
Answer: b
Clarification: Primary follicles mature with the addition of theca, granulosa cells, and antrum to form a mature Graafian follicle. All of these changes along with the completion of the first round of meiosis occurs during the follicular phase also otherwise called as the proliferative phase.

Biology Multiple Choice Questions on “Reproductive Health – Medical Termination of Pregnancy”.

1. What is MTP an acronym for?
a) Menstrual Termination of Pregnancy
b) Medical Test for Pregnancy
c) Menstrual Test for Pregnancy
d) Medical Termination of Pregnancy
Answer: d
Clarification: MTP stands for Medical Termination of Pregnancy. It refers to an intended termination of pregnancy before the baby has been delivered.

2. Of every 5 pregnancies, 1 pregnancy results in induced abortion.
a) True
b) False
Answer: a
Clarification: MTPs or Induced abortions are very frequent. More than 45 million cases of MTPs occur worldwide each year. These account for 1/5th of the total count of pregnancies that are conceived.

3. What is the other term for MTP?
a) Induced abortion
b) Forced death
c) Pregnancy-induced sterilization
d) Unwanted pregnancy
Answer: a
Clarification: MTP is a voluntary act to end the pregnancy. It is also called as induced abortion. After years of dispute, it has been legalized in India.

4. Which of the following is not a reason for the debate of legalizing MTP in many countries?
a) Emotional issues
b) Ethical issues
c) Religious issues
d) Economic issues
Answer: d
Clarification: MTP hasn’t been successfully accepted worldwide. Many countries have failed to accept and legalize it. This holds for emotional, religious, ethical, and social reasons.

5. What restriction has been posed by Government of India on the use of MTP?
a) Illegal female foeticide
b) Illegal male foeticide
c) Illegal drug smuggling
d) Illegal use of narcotics
Answer: a
Clarification: India has a high rate of illegal female foeticides. With the advent of sex determination, this number has only increased. In order to prevent MTP from resulting in female foeticides, the Government of India has posed a restriction to check this issue.

6. Which of the following is not the correct reason for the use of MTP?
a) Get rid of unwanted pregnancy
b) Terminate pregnancies that are fatal to mother
c) Terminate pregnancies that are fatal to foetus
d) Female foeticide
Answer: d
Clarification: The purpose of MTP is to prevent an unwanted pregnancy that could have arisen due to casual unprotected coitus or incorrect use of contraceptive or due to rapes. They are also aimed at rescuing mothers from fatal pregnancies or from preventing parents from the shocks and expenses of a fatal fetus. They are not designed for female foeticide. Hence female foeticide has been illegalized by the Government of India.

7. The primary purpose of MTP is to prevent the population rise.
a) True
b) False
Answer: b
Clarification: MTPs or Induced abortions are aimed at reducing the burden of families by getting rid of unwanted pregnancies. They are also aimed at saving the mother when pregnancy can be harmful. They are not aimed at preventing population rise but have resulted in controlling the population growth to some extent.

8. What period of pregnancy are the MTPs safest?
a) First trimester
b) Second trimester
c) Third trimester
d) Fourth trimester
Answer: a
Clarification: Up to 12 weeks of pregnancy, the embryos are small enough and most straightforward to remove. This is the period of the first trimester. MTPs are most effective during this period.

Biology Online Quiz for MBBS Entrance Exams on “Chromosomal Theory of Inheritance-2”.

1. What is called a reduction division?
a) Mitosis
b) Meiosis
c) Mitrosis
d) Cleavage
Answer: b
Clarification: During the process of meiosis, each daughter cell gets only half the original chromosomal content. Hence it is called the reduction division.

2. Chromosomes occur _________; genes occur _________
a) singly, singly
b) singly, in pairs
c) in pairs, singly
d) in pairs, in pairs
Answer: d
Clarification: A diploid cell has double the set of chromosomal content. Hence there are two copies for each chromosome present. These are called homologous chromosomes. Now, genes are fragments of DNA present on the chromosomes. Hence they also occur in pairs, with one gene present on each homologous chromosomes.

3. Alleles of a gene are located on ________
a) homologous chromosomes
b) heterologous chromosomes
c) homologous chromatids
d) heterologous chromatids
Answer: a
Clarification: The alleles of a gene compete or support each other for expression. Hence, they have to be present at homologous sites and on homologous chromosomes.

4. The duplication of chromosomes occurs during _____
a) G1 phase
b) G2 phase
c) G0 phase
d) G3 phase
Answer: b
Clarification: G2 phase is the biosynthetically active phase. During this phase, a lot of energy is spent by the cell to grow and duplicate its genomic content.

5. When does the first segregation of chromosomes occur during meiosis?
a) Meiosis I Anaphase
b) Meiosis I Telophase
c) Meiosis II Anaphase
d) Meiosis II Telophase
Answer: a
Clarification: The segregation of chromosomes occurs when the spindle fibers pull the fibers pull the chromosomes to the poles and away from the metaphase plate. The first such segregation occurs during meiosis I Anaphase.

6. When does the second segregation of chromosomes occur during meiosis?
a) Meiosis I Anaphase
b) Meiosis I Telophase
c) Meiosis II Anaphase
d) Meiosis II Telophase
Answer: c
Clarification: Meiosis takes place in two phases and involves the separation of chromosomes twice. The second segregation occurs in the Anaphase of Meiosis II.

7. When does the first segregation of genes occur during meiosis?
a) Meiosis I Anaphase
b) Meiosis I Telophase
c) Meiosis II Anaphase
d) Meiosis II Telophase
Answer: a
Clarification: Genes occur in pairs. At the start of meiosis, there are four copies of each gene. They are segregated first during Anaphase I, where each pole receives a pair of each gene.

8. When does the second segregation of chromosomes occur during meiosis?
a) Meiosis I Anaphase
b) Meiosis I Telophase
c) Meiosis II Anaphase
d) Meiosis II Telophase
Answer: c
Clarification: Genes are present as four copies, two of each allele at the onset of meiosis. They are segregated twice: first during Anaphase I and second during Anaphase II. At the end of which, each daughter cell has only one copy of the gene.

9. If the cell at G1 phase at 2 Giga base pairs of DNA, what is the DNA content of the cell right before Telophase II?
a) 1 Giga base pairs
b) 2 Giga base pairs
c) 3 Giga base pairs
d) 4 Giga base pairs
Answer: b
Clarification: Cell at G1 phase has a pair of chromosomes. By the end of Anaphase II, it still has a pair of chromosomes. Hence the DNA content would be almost the same as at the time of G1.

10. If the cell at G1 phase at 2 Giga base pairs of DNA, what is the DNA content of the cell right before Telophase I?
a) 1 Giga base pairs
b) 2 Giga base pairs
c) 3 Giga base pairs
d) 4 Giga base pairs
Answer: d
Clarification: Cells undergo DNA duplication during G2 phase. This is split at the end of Meiosis I. However, until the Telophase I, the cell retains twice the DNA content as at the onset of G1.

11. If the cell at G1 phase at 2 Giga base pairs of DNA, what is the DNA content of the cell right after Telophase II?
a) 1 Giga base pairs
b) 2 Giga base pairs
c) 3 Giga base pairs
d) 4 Giga base pairs
Answer: d
Clarification: The cell starts with two copies of each chromosome during the G1 phase. G2 phase witnesses DNA duplication. However, by the end of Meiosis II, cell splits into four, and each germ cell receives a single copy of each chromosome. Thus, the DNA content at the end of meiosis would be half what it was at the time of onset.

12. The alignment of the chromosome pairs at the metaphase plate during Meiosis I is dependent on other chromosomal pairs.
a) True
b) False
Answer: b
Clarification: The alignment of chromosomal pairs is independent of each other. This is what leads to the statement of the chromosomal basis of inheritance.

13. What phase of Meiosis results in the different combinations of chromosomes occurring in the germ cells?
a) Metaphase I
b) Anaphase I
c) Metaphase II
d) Anaphase II
Answer: a
Clarification: The independent segregation of chromosome pairs occurs during the Metaphase I. This leads to the variations in the daughter cells or germ cells.

14. The variations observed in the daughter cells arise during Metaphase I.
a) True
b) False
Answer: a
Clarification: The Metaphase I involve the independent segregation of the chromosomal pairs by their independent arrangement at the Metaphase plate. This led to the variations observed in the daughter cells.

15. What is each copy of the duplicated chromosome called?
a) Chromatid
b) Chromomere
c) Kinetochore
d) Chromonema
Answer: a
Clarification: The chromosomes duplicate during the G2 phase of the cell cycle. Each copy of the chromosome is identical and is hence called a chromatid. The G2 phase is followed by M phase or meiotic phase, where the chromatids align together at the metaphase plate followed by segregation during the anaphase.

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Biology Multiple Choice Questions on “Properties of Genetic Material (DNA versus RNA)”.

1. Which of the following criterion needn’t be fulfilled by the genetic material?
a) Occurrence of replication
b) Should be able to express itself in the form of “Bohr’s characters”
c) Provision of scope for the mutation that is required for evolution
d) It should be chemically and structurally stable
Answer: b
Clarification: A genetic material must be both chemically and structurally stable. It must be able to replicate. It should provide scope for the evolutionary changes. But it should also be able to express itself in the form of “Mendelian characters” and not “Bohr’s characters”. These Mendelian characters refer to the three laws that were proposed by Gregor Mendel.

2. Which of the following is not a characteristic of RNA?
a) It has ribose sugar molecules in the nucleotides
b) It is a single stranded molecule
c) It is not stable under alkaline conditions
d) All the 3 types of RNA are involved in protein synthesis
Answer: c
Clarification: The hydrogen atom which is attached to the hydroxyl group on the 2’- C atom of the RNA can be easily deprotonated. The presence of larger grooves in RNA is also a reason for it not being stable under alkaline conditions. But under the same condition, the DNA molecule will be stable for it has smaller grooves which cannot be easily attacked or penetrated.

3. Which of the following criterion cannot be fulfilled by protein?
a) Formation of polypeptide chains
b) Generation of its replica
c) Formation of alpha helix and beta sheets
d) Non covalent bonds are present between amino acids
Answer: b
Clarification: Proteins form polypeptide chains by the peptide bond formation between amino acids. Their different folding statures results in the formation of non-covalent bonds as well as the different forms of proteins. Despite these capabilities, proteins lack the ability to generate their replica.

4. Stability is not a property of genetic material.
a) True
b) False
Answer: b
Clarification: The genetic material of an organism should be stable and not change during the course of an organism or person’s lifetime. If any changes are to occur, then variations and problems will arise. It is also clearly inferred from the “transforming principle” of Griffith from his experiments revolving around the R and S strains of the bacterium that stability persists.

5. Stability of the genetic material can also be inferred from the “transforming principle”.
a) True
b) False
Answer: a
Clarification: Heat killed the bacterium but, it didn’t destroy all of its genetic material characteristics. This was proved by Griffith in his experiments concerning about the transformation principles. From this it can be inferred that the stability of the genetic material (either DNA or RNA) cannot be entirely killed. The stability of the genetic can be seen.

6. What will happen when the 2 complementary strands of the DNA are heated up and brought together?
a) They will repel each due to the charges formed
b) They will attract each other due to the charges formed
c) They will become non-complementary to each other
d) They will combine with each other under appropriate conditions
Answer: d
Clarification: From the Griffith’s experiment related to the transforming principle, we could understand that the genetic material still possessed some stability. Likewise, the genetic material DNA which is present in this case also has the capability to join the 2 complementary strands despite it being heated up under appropriate conditions.

7. Which of the following statements is correct regarding DNA and RNA?
a) DNA is highly reactive
b) RNA is not catalytic
c) RNA cannot be easily degraded
d) DNA is a better genetic material than RNA
Answer: d
Clarification: DNA is comparatively less reactive than RNA. The 2’-OH group which is present at the nucleotide of the RNA is the reactive group. This makes the RNA highly reactive in comparison to the DNA. RNA is also catalytic and liable. It cannot be easily degraded. Due to these reasons, the conclusion is that that DNA is the better genetic material than the RNA.

8. The presence of which base in the place of uracil makes the DNA more stable?

a) Adenine
b) Cytosine
c) Thymine
d) Guanine
Answer: c
Clarification: In the case of DNA, thymine is found in the place of uracil. Uracil is found to make a double hydrogen bond with Adenine in RNA. The resistance showed by thymine towards all the photochemical mutations is what makes the DNA more stable.

9. At what rate does the RNA mutate as compared to DNA?
a) Faster rate
b) Slower rate
c) Moderate rate
d) Depending on the medium
Answer: a
Clarification: Mutations can be seen in both DNA and RNA. But RNA mutates at a much faster pace in comparison to the DNA. This is due to the lack of stability that is seen in RNA. Likewise, the viruses which contain RNA as their genetic material also mutate at a faster rate. Their life span will stand short on the contrary.

10. RNA codes are used for translation into which of the following?
a) Genes
b) DNA
c) Proteins
d) Carbohydrate
Answer: c
Clarification: The three types of RNA are r-RNA, t-RNA and m-RNA. These 3 different types of RNA are responsible for the process of translation (translation of RNA into proteins). RNA codes for different amino acid sequences which finally when combined together forms the protein.

11. Which of the following is responsible for the transmission of genetic information?
a) DNA
b) RNA
c) Proteins
d) Mitochondrion
Answer: b
Clarification: The storage of the genetic information takes place in the DNA. It carries all the necessary information needed for heredity. The stability of the DNA is more too, this helps in carrying information. During the central dogma, DNA in transcripted to RNA after which RNA will be responsible for the transmission of the genetic material.

12. Which of the following is responsible for the storage of genetic material?
a) DNA
b) RNA
c) Proteins
d) Ribosome
Answer: a
Clarification: DNA is a stable genetic molecule in comparison to the RNA. So, the carriage of the genetic information will be carried out by the DNA. The transmission of the genetic material will be done by RNA as it is comparatively less stable.

Biology Assessment Questions and Answers on “Origin and Evolution of Man – 3”.

1. What is another name of human evolution?
a) Neogenesis
b) Anthropogenesis
c) Metagenesis
d) Fossilizes
Answer: b
Clarification: Human evolution or anthropogenesis is part of biological evolution which studies the emergence of Homo sapiens sapiens. They were the distinct species from other hominids, great apes and placental mammals.

2. Propliopithecus originated in _____ epoch.
a) Oligocene
b) Miocene
c) Pliocene
d) Azaacene
Answer: a
Clarification: Origin and evolution of Propliopithecus were in an Oligocene epoch so-called as Oligocene apes. They originated about 30-35 million years ago. Origin of man started from Propliopithecus and diverged to many other species.

3. Who was known as Miocene apes?
a) Proconsul
b) Agyptopithecus
c) Ramapithecus
d) Dryopithecus
Answer: b
Clarification: Origin and evolution of Agyptopithecus occurred in late Oligocene and Miocene epoch, so-called as Miocene apes. They were fossils that remained in Miocene rocks. They evolved after Propliopithecus.

4. Who discovered Dryopithecus and Kenyapithecus?
a) Leakey
b) Lewis
c) Joseph
d) Sam
Answer: a
Clarification: Dryopithecus and Kenyapithecus fossils were discovered by Leakey. Dryopithecus was discovered from Eastern Africa near Victoria lake in Kenya. Kenyapithecus was discovered from Kenya.

5. Which of the following is not a characteristic of Dryopithecus?
a) Semi erect posture
b) Evolution about 15-20 million years ago
c) Teeth larger and sharper
d) Meat eater
Answer: d
Clarification: They were not meat eaters whereas they were vegetarian by nature. They only ate fruits. The remaining options are true characters of Dryopithecus.

6. Ramapithecus and Shivapithecus were discovered from which place in India?
a) Himalayan hills
b) Shivalik hills
c) Nagaraj hills
d) Ganga hills
Answer: b
Clarification: Ramapithecus and Shivapithecus were discovered from Shivalik hills in India. They were discovered by Lewis. These species spent most of the time on land. They originated in Pliocene epoch.

7. Ramapithecus was more ape-like whereas Dryopithecus was more man-like.
a) True
b) False
Answer: b
Clarification: It was the opposite. Ramapithecus was more man-like whereas Dryopithecus was more ape-like. Ramapithecus was the earliest hominid fossil showed characters of man whereas Dryopithecus was the earliest fossil ape showed the characters of an ape.

8. Who discovered Australopithecus?
a) Alexander Fleming
b) Lewis Jackson
c) Prof. Raymond dart
d) Gregor Mendel
Answer: c
Clarification: Professor Raymond dart discovered a fossil skull of a 5-6-year-old baby from the old Pliocene rocks. It was located in the Tuang region in South Africa. He first named it Tuang baby and he renamed it, A. Africanus.

9. Australopithecus was also known as the ______
a) first ape man
b) first human
c) human baby
d) humanoid
Answer: a
Clarification: Australopithecus was known as the first ape-man. They had both man and ape-like characters. They had the same dental formula and had a thick growth of hair on the body.

10. Which of the following is the correct statement regarding Australopithecus?
a) They lived in West African grasslands
b) They lived about 5-6 million years ago
c) They essentially ate fruits
d) They hunted with guns
Answer: c
Clarification: They lived about 3-2 million years ago in East African grasslands. They essentially ate fruits and hunted with stones. They had a less cranial capacity of 600 c.c.

11. Which fossil of the ape was known as the connecting link between apes and man?
a) Ramapithecus
b) Dryopithecus
c) Shivapithecus
d) Australopithecus
Answer: d
Clarification: Australopithecus was known as the connecting link between apes and man. They had complete erect posture and showed bipedal locomotion. It was the first man to stand erect.

Biology Assessment Questions,