Nucleic Acids Flashcards
What are the two types of nucleic acids?
DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid)
Both are important information-carrying molecules.
What is the primary function of DNA in living cells?
Holds genetic information
DNA is crucial for the storage of genetic instructions.
What is the primary function of RNA in living cells?
Transfers genetic information from DNA to ribosomes
RNA plays a key role in protein synthesis.
What are the monomers of nucleic acids called?
Nucleotides
Nucleotides are the building blocks of DNA and RNA.
What three components make up a nucleotide?
- 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.
Who discovered the structure of DNA?
Watson and Crick
They are credited with elucidating the double helix structure of DNA.
What is the structure of DNA?
Two polynucleotide strands joined by hydrogen bonding to form a double helix
This structure is crucial for its function in carrying genetic information.
What sugar is found in DNA nucleotides?
Deoxyribose
This distinguishes DNA from RNA, which contains ribose.
What are the four nitrogen-containing bases in DNA?
- Cytosine
- Thymine
- Adenine
- Guanine
These bases are fundamental to the genetic coding in DNA.
How are nucleotides within each DNA strand joined together?
By phosphodiester bonds formed in condensation reactions
This linkage forms the backbone of the DNA structure.
What forms the backbone of the polynucleotide strands in DNA?
Sugar and phosphate
The backbone supports the structure of the DNA helix.
How are the nitrogen bases in DNA oriented?
Towards the centre of the helix
This orientation protects the bases from reacting with other chemicals.
What is the complementary base pairing in DNA?
- Adenine pairs with Thymine
- Guanine pairs with Cytosine
This specificity is crucial for accurate DNA replication.
Fill in the blank: The sugar in RNA is _______.
Ribose
This distinguishes RNA from DNA, which contains deoxyribose.
What type of bonds ion the bases of DNA?
Hydrogen bonds
Although individually weak, hydrogen bonds collectively maintain a stable structure.
What structure does the DNA helix further form?
Super helix
This provides a compact store of genetic information.
What are the components of the DNA backbone?
Sugar-phosphate backbones
This forms the structural framework of DNA.
What is the relationship between DNA strands?
They are anti-parallel
This means they run in opposite directions.
If DNA has 30% adenine, what is the percentage of guanine?
20%
According to Chargaff’s rules, adenine pairs with thymine and guanine pairs with cytosine.
If DNA has 28% thymine, what is the percentage of cytosine?
22%
This follows the same pairing rules as above.
What is a gene?
A section of DNA that contains coded information
Genes code for polypeptides that determine the nature and development of organisms.
What essential function does DNA perform during cell division?
Self-replicate
This occurs due to complementary base pairing.
What can alterations in the DNA base sequence lead to?
Mutations
Mutations provide genetic diversity and are the basis for evolution via natural selection.
What are the structural features of DNA?
- 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.
What is one function of the sugar-phosphate backbone?
Gives strength
This structural feature enhances the integrity of DNA.
How does DNA’s structure protect the sequence of bases?
By providing a compact shape
This reduces the likelihood of damage to the genetic information.
What allows the DNA helix to unzip easily for replication?
Individual hydrogen bonds are weak
This characteristic facilitates the replication process.
What is the main difference between RNA and DNA?
RNA has ribose and uracil instead of deoxyribose and thymine
RNA bases include adenine, guanine, cytosine, and uracil.
What type of structure do mRNA and tRNA have compared to DNA?
Single stranded
DNA is double stranded.
What is a key function of DNA related to polypeptides?
Codes for specific sequence of amino acids
This coding is crucial for protein synthesis.
What facilitates accurate replication of information in DNA?
Complementary base pairing
This ensures that the genetic code is preserved during replication.
What type of molecule is ATP grouped with?
Nucleic acids such as DNA and RNA
ATP is considered a nucleic acid because it contains ribose and phosphate groups.
What is DNA replication?
The process of copying DNA during cell division
DNA replication is crucial for growth and reproduction.
What enzyme breaks the hydrogen bonds during DNA replication?
DNA helicase
DNA helicase unwinds the DNA double helix.
What role do the strands of DNA play during replication?
Each strand acts as a template for the formation of two new complementary strands
This is essential for ensuring accurate DNA replication.
What is the significance of complementary base pairing in DNA replication?
It ensures accurate alignment of nucleotides
Adenine pairs with Thymine and Cytosine pairs with Guanine.
What type of bonds form between DNA nucleotides during replication?
Phosphodiester bonds
These bonds are formed in condensation reactions catalyzed by DNA polymerase.
What is the outcome of DNA replication?
Two identical DNA molecules
Each new molecule contains one original strand and one new strand.
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 _______.
Semi-conservative replication
What type of replication did Meselson and Stahl demonstrate?
Semi-conservative replication
This means each new DNA molecule consists of one old strand and one new strand.
Which bacterium was used by Meselson and Stahl in their experiment?
E. coli
This bacterium was grown in media with heavy and normal isotopes of nitrogen.
What heavy isotope was used to grow E. coli in Meselson and Stahl’s experiment?
15N
This isotope replaced the normal isotope 14N in the growth medium.
What was the purpose of transferring bacteria to a medium containing only 14N?
To observe the incorporation of the normal isotope into newly synthesized DNA
This helped determine the nature of DNA replication.
What method was used to analyze the DNA after bacterial division?
Centrifugation
This technique separates DNA based on density.
What is ATP?
Adenosine triphosphate
It is the immediate energy source for biological processes.
What components make up a single molecule of ATP?
Ribose, adenine, and three phosphate groups
These components combine to form the structure of ATP.
What enzyme catalyzes the hydrolysis of ATP?
ATP hydrolase
This enzyme facilitates the breakdown of ATP to ADP and Pi.
What are the products of ATP hydrolysis?
ADP and inorganic phosphate (Pi)
This reaction releases energy that can be used for cellular processes.
What can the energy released during ATP hydrolysis be coupled to?
Energy-requiring reactions within cells
An example is protein synthesis.
What happens to the inorganic phosphate released during ATP hydrolysis?
It can be used to phosphorylate other compounds
This process often makes the compounds more reactive.
What reaction restores ATP from ADP and Pi?
Condensation reaction
This process is catalyzed by the enzyme ATP synthase.
During which processes is ATP resynthesized?
Photosynthesis and respiration
The energy from these processes enables ATP synthesis.
