Chapter 2: Nucleic acids Flashcards
What does RNA stand for?
Ribonucleic acid
What does DNA stand for?
Deoxyribonucleic acid
What does DNA do?
it carries genetic information
What monomers are DNA and RNA made of?
Nucleotides
What are the three components that make up nucleotides?
a pentose sugar, a phosphate group and a nitrogen-containing organic base
What are the five types of organic base?
Cytosine, Adenine, Guanine, Thymine, Uracil
How can two nucleotides be joined together?
by a condensation reaction, that forms a phosphodiester bond between the pentose sugar and phosphate molecule
What is RNA?
a singe stranded polynucleotide, where the pentose sugar is ribose
What are the organic bases of RNA?
Adenine, Guanine, Cytosine and Uracil
What is the function of RNA?
Transferring genetic information from DNA to ribosomes
Who discovered the structure of DNA?
James Watson and Francis Crick, in 1953
What are the bonds between the organic bases of two DNA strands?
hydrogen bonds
What base always joins to Adenine on DNA?
Thymine
What base always joins to Guanine?
Cytosine
What are DNA bases said to be, because of their pairings?
Complementary
What are the phosphate and deoxyribose often called in the DNA structure?
The structural backbone of the DNA molecule
What is the structure the DNA strand form when bonded to each other?
a double helix structure
How does the phosphodiester backbone make DNA stable?
It protects the more chemically reactive organic bases inside the double helix.
How do the hydrogen bases between base pairs make DNA stable?
they form bridges between the phosphodiester backbones.
How many hydrogen bonds are between Guanine and Cytosine bases?
Three hydrogen bonds
How many hydrogen bonds are between Thymine and Adenine bases?
Two hydrogen bonds
Why is DNA more stable the more G-C bonds there are?
G-C have three hydrogen bonds, thus more strength
Why is DNA’s stable structure an adaptation for DNA’s function?
It allow DNA to be passed on generation without significant change by mutations. (unrepaired mutations are rare)
The phosphodiester backbone protects the bases from outside chemicals and forces
What is the benefit of the hydrogen bonds in the DNA’s function?
They can easily broken for DNA replication.