Biology

Molecular Biology and Genetics

717 Questions

Molecular biology and genetics explore the structure and function of DNA, RNA, genetic mutations, and heredity. Understanding these building blocks of life is essential for most biology examinations. Review these practice questions to test your molecular genetics knowledge.

DNA structure and basesGenetic mutationsNucleic acids compositionDNA sequencing and replication

Molecular Biology and Genetics Questions

Multiple choice
  1. Adenine and Cytosine

  2. Guanine and Thymine

  3. Cytosine and Thymine

  4. Adenine and Guanine

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Three nucleobases found in nucleic acids Cytosine (C), Thymine (T) and Uracil (U) are pyrimidine derivatives.

Multiple choice
  1. 265 BP

  2. 110 BP

  3. 140 BP

  4. 210 BP

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Nucleosomes is the ellipsoidal bead shape structure with the length of 110A & diameter of 65-70A. Its core composed of an histone octamer & its surface is surrounded by super-helical DNA strand of about 140BP.

Multiple choice
  1. Single circular chromosome is present.

  2. Extrachromosomal plasmids are not commonly seen.

  3. Transcription and translation occurs simultaneously.

  4. Nucleoid is formed by DNA supercoiling.

  5. Small amounts of repetitive DNA present.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is a characteristic of eukaryotes.

Multiple choice
  1. Only 1

  2. Only 2

  3. Only 3

  4. 1 and 2

  5. 2 and 3

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because the term ‘genome’ was given by Hans Winkler, professor of botany at the University of Hamburg, Germany.

Multiple choice
  1. P and Q

  2. P and R

  3. P and S

  4. Q and R

  5. Q and S

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because in eukaryotes, there is a set of positively charged, basic proteins called histones. Histones are rich in the basic amino acid residues, lysines and arginines, and in a typical nucleus, some region of chromatin is loosely packed (and stains light) and is referred to as euchromatin. The chromatin that is more densely packed and stains dark is called as heterochromatin.

Multiple choice

All of the following were contributing factors for the wave of anti-Semitism except:

Directions: Answer the question based on the following passage.

A DNA molecule is made up of two long polymers, the polymers being the mixture of compounds formed by polymerization, and consisting essentially of repeating structural units. The strands are joined together with hydrogen atoms and are woven together in the shape of a double helix. Each of the polymers contains chemicals called nucleotides which in turn can be broken down into many individualized components including four nitrogenous bases that form the basic building block of life and contain all the genetic information that an organism needs. The backbone of the DNA molecule is made up of alternating sugars and phosphates and, being quite strong, it protects the whole from damage and mutation. Since one strand is a photographic negative of the other, it is very easy to replicate the information once the structure of one of the two component strands is known and understood. Replication begins with the unwinding of the helix with an enzyme and it is not mandatory that the replication has to start at the ends of the strand. It can start anywhere and once started, the enzymes create two replication forks that continue to replicate the strand in both the directions. DNA contains all the information necessary for life processes but this information never leaves the nuclei of the cells.

One of the earliest proponents of genetic research and the role of heredity in transmission of genetic disorders, and dare one say human cloning, was the now infamous Josef Menegle, from the concentration camp of Auschwitz in the Second World War. At the acme of Hitler’s power in Germany, and indeed in most of Europe and Africa, Jew hating wasn’t just a wave; it was a way of life with not only the state machinery arrayed against them, but also a lot of otherwise unbiased citizens and fellow humans who were just caught in the maelstrom of events between the hard choices of betraying friends and neighbors and being branded traitors to the cause themselves. The Nazi party and its followers started believing in the own racial superiority and being a Jew or a gypsy meant carrying a perpetual death sentence. Indeed another contemporary of Menegle, Joseph Goebbels, who, from a failed literary writer was to become the minister of propaganda for the Nazis, commenced his attacks on Jews in 1933 and continued through 1938 when they finally took the shape of the notorious ‘Final Solution’, which looked at the total annihilation of the Jews. Menegle was especially interested in studying twins and performed a variety of experiments on them without anesthesia to determine the genetic origins of diseases as at that time medical research into twin physiology was seen as the best tool of studying the variant factor in heredity. Also, he was extremely interested in genetic segregation of the Aryan blood as he thought that Jewish and Roma blood was impure and thought that twins were the best way to carry forward the purity of lineage. Taking forward the Nazi party line of the creation and preservation of the ‘Master Race’, which included thousands of vasectomies and operations on women to weed out the undesirable parts from the population, some even credit Menegle with having impregnated hundreds, perhaps thousands, of women with the Fuhrer’s semen in order to propagate the Aryan race.

  1. Misguided evangelism triggering mass hysteria

  2. Top Drawer's disinformation that played on insecurities of citizens

  3. Sentiment of xenophobia running pandemic in the society

  4. Obsession with genesis of pure stock

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(1) Incorrect; the misplaced hatred forced non-Jewish citizens to turn their backs on friends. (2) Incorrect; the propaganda did affect the non-Jews who feared backlash if they supported Jews. (3) Correct; masses were forced to betray Jews out of fear of reprisals. In any case, since Jews were natives, xenophobia can be appropriately used to refer to them. (4) Incorrect; the Nazis were indeed obsessed with the creation of the 'Master Race'. (5) Incorrect; the Nazis were focused on weeding out the weak and undesirables.

Multiple choice

The passage mentions all of the following except:

Directions: Answer the question based on the following passage.

A DNA molecule is made up of two long polymers, the polymers being the mixture of compounds formed by polymerization, and consisting essentially of repeating structural units. The strands are joined together with hydrogen atoms and are woven together in the shape of a double helix. Each of the polymers contains chemicals called nucleotides which in turn can be broken down into many individualized components including four nitrogenous bases that form the basic building block of life and contain all the genetic information that an organism needs. The backbone of the DNA molecule is made up of alternating sugars and phosphates and, being quite strong, it protects the whole from damage and mutation. Since one strand is a photographic negative of the other, it is very easy to replicate the information once the structure of one of the two component strands is known and understood. Replication begins with the unwinding of the helix with an enzyme and it is not mandatory that the replication has to start at the ends of the strand. It can start anywhere and once started, the enzymes create two replication forks that continue to replicate the strand in both the directions. DNA contains all the information necessary for life processes but this information never leaves the nuclei of the cells.

One of the earliest proponents of genetic research and the role of heredity in transmission of genetic disorders, and dare one say human cloning, was the now infamous Josef Menegle, from the concentration camp of Auschwitz in the Second World War. At the acme of Hitler’s power in Germany, and indeed in most of Europe and Africa, Jew hating wasn’t just a wave; it was a way of life with not only the state machinery arrayed against them, but also a lot of otherwise unbiased citizens and fellow humans who were just caught in the maelstrom of events between the hard choices of betraying friends and neighbors and being branded traitors to the cause themselves. The Nazi party and its followers started believing in the own racial superiority and being a Jew or a gypsy meant carrying a perpetual death sentence. Indeed another contemporary of Menegle, Joseph Goebbels, who, from a failed literary writer was to become the minister of propaganda for the Nazis, commenced his attacks on Jews in 1933 and continued through 1938 when they finally took the shape of the notorious ‘Final Solution’, which looked at the total annihilation of the Jews. Menegle was especially interested in studying twins and performed a variety of experiments on them without anesthesia to determine the genetic origins of diseases as at that time medical research into twin physiology was seen as the best tool of studying the variant factor in heredity. Also, he was extremely interested in genetic segregation of the Aryan blood as he thought that Jewish and Roma blood was impure and thought that twins were the best way to carry forward the purity of lineage. Taking forward the Nazi party line of the creation and preservation of the ‘Master Race’, which included thousands of vasectomies and operations on women to weed out the undesirable parts from the population, some even credit Menegle with having impregnated hundreds, perhaps thousands, of women with the Fuhrer’s semen in order to propagate the Aryan race.

  1. Protected by an organic shield, DNA resists undesirable transformation.

  2. DNA is one of the two indispensable constituents of genetic structure.

  3. The genetic codes are jealously guarded by DNA.

  4. Menegle was one of the earliest proponents of genetic research.

  5. The duplication of DNA strand can start from any point.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(1) Incorrect; the passage mentions that backbone of DNA is quite strong and protects it from damage and mutation. (2) Correct answer. Nowhere does the passage mention that DNA is one of the two indispensable components. (3) Incorrect; the passage states that DNA contains all necessary information for life processes and that the information never leaves the nuclei of the cells. (4) Incorrect; specifically mentioned in the passage. (5) Incorrect; the passage states that the replication can start from any point of the DNA strand.

Multiple choice

Why does the author say, 'the now infamous' while referring to Josef Menegle?

Directions: Answer the question based on the following passage.

A DNA molecule is made up of two long polymers, the polymers being the mixture of compounds formed by polymerization, and consisting essentially of repeating structural units. The strands are joined together with hydrogen atoms and are woven together in the shape of a double helix. Each of the polymers contains chemicals called nucleotides which in turn can be broken down into many individualized components including four nitrogenous bases that form the basic building block of life and contain all the genetic information that an organism needs. The backbone of the DNA molecule is made up of alternating sugars and phosphates and, being quite strong, it protects the whole from damage and mutation. Since one strand is a photographic negative of the other, it is very easy to replicate the information once the structure of one of the two component strands is known and understood. Replication begins with the unwinding of the helix with an enzyme and it is not mandatory that the replication has to start at the ends of the strand. It can start anywhere and once started, the enzymes create two replication forks that continue to replicate the strand in both the directions. DNA contains all the information necessary for life processes but this information never leaves the nuclei of the cells.

One of the earliest proponents of genetic research and the role of heredity in transmission of genetic disorders, and dare one say human cloning, was the now infamous Josef Menegle, from the concentration camp of Auschwitz in the Second World War. At the acme of Hitler’s power in Germany, and indeed in most of Europe and Africa, Jew hating wasn’t just a wave; it was a way of life with not only the state machinery arrayed against them, but also a lot of otherwise unbiased citizens and fellow humans who were just caught in the maelstrom of events between the hard choices of betraying friends and neighbors and being branded traitors to the cause themselves. The Nazi party and its followers started believing in the own racial superiority and being a Jew or a gypsy meant carrying a perpetual death sentence. Indeed another contemporary of Menegle, Joseph Goebbels, who, from a failed literary writer was to become the minister of propaganda for the Nazis, commenced his attacks on Jews in 1933 and continued through 1938 when they finally took the shape of the notorious ‘Final Solution’, which looked at the total annihilation of the Jews. Menegle was especially interested in studying twins and performed a variety of experiments on them without anesthesia to determine the genetic origins of diseases as at that time medical research into twin physiology was seen as the best tool of studying the variant factor in heredity. Also, he was extremely interested in genetic segregation of the Aryan blood as he thought that Jewish and Roma blood was impure and thought that twins were the best way to carry forward the purity of lineage. Taking forward the Nazi party line of the creation and preservation of the ‘Master Race’, which included thousands of vasectomies and operations on women to weed out the undesirable parts from the population, some even credit Menegle with having impregnated hundreds, perhaps thousands, of women with the Fuhrer’s semen in order to propagate the Aryan race.

  1. Because his research methods were crude and lacked finesse.

  2. Because his research has now been proven as flawed.

  3. Because his research though valuable at that time, no longer has credibility.

  4. Because his work disguised sadism as investigation.

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

(1) Incorrect; the details of his experiments show him to be a cruel person deserving infamy. (2) Incorrect; the passage doesn't state whether his research has been proven flawed. (3) Incorrect; no indication if his research was thought valuable at the time. (4) Correct; his inhuman experiments smack of sadist tendencies. (5) Incorrect; 'variant' and 'heredity' are the Red herrings and find but a passing mention.

Multiple choice
  1. A polypeptide of 99 amino acids will form.

  2. A polypeptide of 83 amino acids will form.

  3. A polypeptide of 82 amino acid will form.

  4. A polypeptide of 17 amino acids will form.

  5. Two polypeptides of 83 and 17 amino acids respectively will form.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A polypeptide of 82 amino acid will form. As UAG is a stop codon, it will not attach with any anticodon loop of tRNAbecause polypeptide elongation will be stopped at the 83rd position. Therefore, polypeptide chain with 82 amino acids will form.