Nucleic Acids

Question 1

What are the two types of nucleic acids?

Answer 1

DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid)

Both are important information-carrying molecules.

Question 2

What is the primary function of DNA in living cells?

Answer 2

Holds genetic information

DNA is crucial for the storage of genetic instructions.

Question 3

What is the primary function of RNA in living cells?

Answer 3

Transfers genetic information from DNA to ribosomes

RNA plays a key role in protein synthesis.

Question 4

What are the monomers of nucleic acids called?

Answer 4

Nucleotides

Nucleotides are the building blocks of DNA and RNA.

Question 5

What three components make up a nucleotide?

Answer 5

• A Pentose (five carbon sugar)
• A nitrogen-containing organic base
• A phosphate group (phosphoric acid)

These components are essential for the structure of nucleic acids.

Question 6

Who discovered the structure of DNA?

Answer 6

Watson and Crick

They are credited with elucidating the double helix structure of DNA.

Question 7

What is the structure of DNA?

Answer 7

Two polynucleotide strands joined by hydrogen bonding to form a double helix

This structure is crucial for its function in carrying genetic information.

Question 8

What sugar is found in DNA nucleotides?

Answer 8

Deoxyribose

This distinguishes DNA from RNA, which contains ribose.

Question 9

What are the four nitrogen-containing bases in DNA?

Answer 9

• Cytosine
• Thymine
• Adenine
• Guanine

These bases are fundamental to the genetic coding in DNA.

Question 10

How are nucleotides within each DNA strand joined together?

Answer 10

By phosphodiester bonds formed in condensation reactions

This linkage forms the backbone of the DNA structure.

Question 11

What forms the backbone of the polynucleotide strands in DNA?

Answer 11

Sugar and phosphate

The backbone supports the structure of the DNA helix.

Question 12

How are the nitrogen bases in DNA oriented?

Answer 12

Towards the centre of the helix

This orientation protects the bases from reacting with other chemicals.

Question 13

What is the complementary base pairing in DNA?

Answer 13

• Adenine pairs with Thymine
• Guanine pairs with Cytosine

This specificity is crucial for accurate DNA replication.

Question 14

Fill in the blank: The sugar in RNA is _______.

Answer 14

Ribose

This distinguishes RNA from DNA, which contains deoxyribose.

Question 15

What type of bonds ion the bases of DNA?

Answer 15

Hydrogen bonds

Although individually weak, hydrogen bonds collectively maintain a stable structure.

Question 16

What structure does the DNA helix further form?

Answer 16

Super helix

This provides a compact store of genetic information.

Question 17

What are the components of the DNA backbone?

Answer 17

Sugar-phosphate backbones

This forms the structural framework of DNA.

Question 18

What is the relationship between DNA strands?

Answer 18

They are anti-parallel

This means they run in opposite directions.

Question 19

If DNA has 30% adenine, what is the percentage of guanine?

Answer 19

20%

According to Chargaff’s rules, adenine pairs with thymine and guanine pairs with cytosine.

Question 20

If DNA has 28% thymine, what is the percentage of cytosine?

Answer 20

22%

This follows the same pairing rules as above.

Question 21

What is a gene?

Answer 21

A section of DNA that contains coded information

Genes code for polypeptides that determine the nature and development of organisms.

Question 22

What essential function does DNA perform during cell division?

Answer 22

Self-replicate

This occurs due to complementary base pairing.

Question 23

What can alterations in the DNA base sequence lead to?

Answer 23

Mutations

Mutations provide genetic diversity and are the basis for evolution via natural selection.

Question 24

What are the structural features of DNA?

Answer 24

• Sugar-phosphate backbone
• Helix
• Double stranded
• Large molecule
• Many hydrogen bonds
• Sequence of bases
• Complementary base-pairing

These features contribute to DNA’s stability and functionality.

Question 25

What is one function of the sugar-phosphate backbone?

Answer 25

Gives strength ## Footnote This structural feature enhances the integrity of DNA.

Question 26

How does DNA's structure protect the sequence of bases?

Answer 26

By providing a compact shape ## Footnote This reduces the likelihood of damage to the genetic information.

Question 27

What allows the DNA helix to unzip easily for replication?

Answer 27

Individual hydrogen bonds are weak ## Footnote This characteristic facilitates the replication process.

Question 28

What is the main difference between RNA and DNA?

Answer 28

RNA has ribose and uracil instead of deoxyribose and thymine ## Footnote RNA bases include adenine, guanine, cytosine, and uracil.

Question 29

What type of structure do mRNA and tRNA have compared to DNA?

Answer 29

Single stranded ## Footnote DNA is double stranded.

Question 30

What is a key function of DNA related to polypeptides?

Answer 30

Codes for specific sequence of amino acids ## Footnote This coding is crucial for protein synthesis.

Question 31

What facilitates accurate replication of information in DNA?

Answer 31

Complementary base pairing ## Footnote This ensures that the genetic code is preserved during replication.

Question 32

What type of molecule is ATP grouped with?

Answer 32

Nucleic acids such as DNA and RNA ## Footnote ATP is considered a nucleic acid because it contains ribose and phosphate groups.

Question 33

What is DNA replication?

Answer 33

The process of copying DNA during cell division ## Footnote DNA replication is crucial for growth and reproduction.

Question 34

What enzyme breaks the hydrogen bonds during DNA replication?

Answer 34

DNA helicase ## Footnote DNA helicase unwinds the DNA double helix.

Question 35

What role do the strands of DNA play during replication?

Answer 35

Each strand acts as a template for the formation of two new complementary strands ## Footnote This is essential for ensuring accurate DNA replication.

Question 36

What is the significance of complementary base pairing in DNA replication?

Answer 36

It ensures accurate alignment of nucleotides ## Footnote Adenine pairs with Thymine and Cytosine pairs with Guanine.

Question 37

What type of bonds form between DNA nucleotides during replication?

Answer 37

Phosphodiester bonds ## Footnote These bonds are formed in condensation reactions catalyzed by DNA polymerase.

Question 38

What is the outcome of DNA replication?

Answer 38

Two identical DNA molecules ## Footnote Each new molecule contains one original strand and one new strand.

Question 39

Fill in the blank: The term used to describe the type of replication where each new DNA molecule contains one original and one new strand is _______.

Answer 39

Semi-conservative replication

Question 40

What type of replication did Meselson and Stahl demonstrate?

Answer 40

Semi-conservative replication ## Footnote This means each new DNA molecule consists of one old strand and one new strand.

Question 41

Which bacterium was used by Meselson and Stahl in their experiment?

Answer 41

E. coli ## Footnote This bacterium was grown in media with heavy and normal isotopes of nitrogen.

Question 42

What heavy isotope was used to grow E. coli in Meselson and Stahl's experiment?

Answer 42

15N ## Footnote This isotope replaced the normal isotope 14N in the growth medium.

Question 43

What was the purpose of transferring bacteria to a medium containing only 14N?

Answer 43

To observe the incorporation of the normal isotope into newly synthesized DNA ## Footnote This helped determine the nature of DNA replication.

Question 44

What method was used to analyze the DNA after bacterial division?

Answer 44

Centrifugation ## Footnote This technique separates DNA based on density.

Question 45

What is ATP?

Answer 45

Adenosine triphosphate ## Footnote It is the immediate energy source for biological processes.

Question 46

What components make up a single molecule of ATP?

Answer 46

Ribose, adenine, and three phosphate groups ## Footnote These components combine to form the structure of ATP.

Question 47

What enzyme catalyzes the hydrolysis of ATP?

Answer 47

ATP hydrolase ## Footnote This enzyme facilitates the breakdown of ATP to ADP and Pi.

Question 48

What are the products of ATP hydrolysis?

Answer 48

ADP and inorganic phosphate (Pi) ## Footnote This reaction releases energy that can be used for cellular processes.

Question 49

What can the energy released during ATP hydrolysis be coupled to?

Answer 49

Energy-requiring reactions within cells ## Footnote An example is protein synthesis.

Question 50

What happens to the inorganic phosphate released during ATP hydrolysis?

Answer 50

It can be used to phosphorylate other compounds ## Footnote This process often makes the compounds more reactive.

Question 51

What reaction restores ATP from ADP and Pi?

Answer 51

Condensation reaction ## Footnote This process is catalyzed by the enzyme ATP synthase.

Question 52

During which processes is ATP resynthesized?

Answer 52

Photosynthesis and respiration ## Footnote The energy from these processes enables ATP synthesis.