Topic 1: Biological Molecules Part 2 Flashcards
What are nucleic acids?
Important information-carrying molecules.
What are two examples of nucleic acids?
Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)
What are the roles of DNA and RNA in all living cells?
DNA holds genetic information.
RNA transfers genetic information from DNA to the ribosomes during protein synthesis.
What is a gene?
A base sequence of DNA that codes for the production of a particular polypeptide.
What is a pentose?
A 5-carbon monosaccharide.
What are the components of a DNA nucleotide?
Deoxyribose (a pentose sugar), a phosphate group, an organic nitrogenous base (adenine, cytosine, guanine or thymine).
What are the 4 bases used in DNA and 1 different base used in RNA?
Adenine, cytosine, guanine, thymine
Uracil
What are the components of an RNA nucleotide?
Ribose (a pentose sugar), a phosphate group, an organic nitrogenous base (adenine, cytosine, guanine or uracil)
How is a phosphodiester bond formed?
A condensation reaction between the phosphate group of one nucleotide and the pentose sugar of another.
What is a DNA molecule?
A relatively long double helix with two polynucleotide chains held together by hydrogen bonds between specific complementary bases. Complementary bases pair up to form base pairs.
What is a polynucleotide?
A polymer of nucleotides.
What is a single polynucleotide chain also known as?
A DNA strand.
How do the 2 stands in a DNA molecule run?
They run in opposite directions, the strands run anti parallel to each other.
What is the sugar-phosphate backbone?
It is composed of alternating sugar and phosphate groups. It forms the structural framework of nucleic acids.
Why is DNA a very stable molecule?
- The sugar-phosphate backbone protects the organic bases from chemical attack.
- The hydrogen bonds between the many pairs of complementary bases hold the two stands together. Hydrogen bonds are individually weak, but collectively strong.
