DNA and RNA Flashcards
(27 cards)
What is the function of DNA in cells?
DNA stores genetic information (instructions for growth & development).
What is the role of RNA in protein synthesis?
RNA transfers genetic information from DNA to ribosomes for protein synthesis (translation).
What are ribosomes made of?
Ribosomes are made of RNA and protein.
List the three components of a nucleotide.
A pentose sugar, a phosphate group, and a nitrogen-containing organic base.
Which sugar is found in DNA and which in RNA?
DNA → deoxyribose; RNA → ribose.
Name the four bases found in DNA and the four found in RNA.
DNA: A, T, C, G
RNA: A, U, C, G
What type of reaction joins nucleotides together?
Condensation reactions.
What bond is formed between nucleotides?
Phosphodiester bond (between sugar of one nucleotide and phosphate of the next).
What is the result of many nucleotides joined together?
A sugar-phosphate backbone is the result of many nucleotides joined together.
What breaks the phosphodiester bonds between nucleotides?
Hydrolysis breaks these bonds.
Describe the overall structure of DNA.
DNA is a double-stranded helix made of two antiparallel polynucleotide strands twisted into a double helix.
Which bases pair together in DNA and how many hydrogen bonds are between them?
A pairs with T (2 hydrogen bonds)
C pairs with G (3 hydrogen bonds)
What does complementary base pairing ensure in DNA replication?
Complementary base pairing ensures accuracy in replication
What is meant by DNA strands being antiparallel?
One strand runs 5’ to 3’, the other 3’ to 5’.
Why is DNA tightly coiled?
DNA is very long and coiled tightly to fit in nucleus.
Explain four structural adaptations of DNA for its function.
- Double helix – compact structure that provides stability through base stacking interactions.
- Sugar-phosphate backbone – protects internal nitrogenous bases from damage.
- Hydrogen bonds – weak enough to allow strand separation during replication, but collectively maintain structural integrity.
- Long molecule with many base pairs – stores a large amount of genetic information.
- Complementary base pairing – enables accurate replication of genetic material.
Is RNA single or double stranded?
Single-stranded.
How does the length of RNA compare to DNA?
RNA is shorter than DNA.
What base does RNA use instead of thymine?
Uracil (U) replaces thymine (T).
What sugar is present in RNA?
Ribose sugar instead of deoxyribose.
DNA vs RNA Comparison
Feature DNA RNA
Strands Double-stranded Single-stranded
Sugar Deoxyribose Ribose
Bases A, T, C, G A, U, C, G
Length Long Short
Helix Double helix No helix
What are purines and which bases are purines?
Purines are 2-ring bases: Adenine (A), Guanine (G).
What are pyrimidines and which bases are pyrimidines?
Pyrimidines are 1-ring bases: Cytosine (C), Thymine (T), Uracil (U).
Why does one purine always pair with one pyrimidine?
One purine always pairs with one pyrimidine to maintain a uniform width.
