Nucleic acids and DNA replication

What is DNA and RNA?

Both are kinds of nucleic acid that carry information

What are the monomers that make up DNA and RNA?

Nucleotides

What’s the general structure of a nucleotide?

Pentose sugar connected to a phosphate group and nitrogen-containing base

What are the bonds that hold together nucleotides and what sort of reaction joins them together?

Phosphodiester bonds form between the phosphate group of one nucleotide and the pentose sugar of another nucleotide in a condensation reaction

What’s the structure of a DNA nucleotide?

Deoxyribose sugar connected to a phosphate group and nitrogen-containing base; base could be adenine, thymine, cytosine, or guanine; A-T, C-G

What’s the structure of DNA?

Double helix structure with two long polynucleotide strands wound around each other; complementary bases held together by hydrogen bonds; sugar-phosphate backbone along antiparallel strands

What’s the structure of RNA and the RNA nucleotide?

Ribose sugar connected to phosphate group and nitrogen-containing base; uracil instead of thymine; A-U, C-G; nucleotides form a single polynucleotide strand (not double) and RNA strands are much shorter than DNA polynucleotides

Why did many scientists doubt that DNA carried the genetic code?

Because of its relative simplicity

Why does DNA need to replicate?

DNA clones before cell division so new cell has full amount of DNA

Through what ‘method’ does DNA replicate?

Semi-conservative replication

Describe the process of semi-conservative replication

DNA helicase breaks hydrogen bonds between bases on two polynucleotide chains forming two single strand templates; Free-floating DNA nucleotides are attracted to their complementary exposed bases (A to T, C to G); DNA polymerase joins adjacent nucleotides in condensation reaction sealing the phosphodiester backbone and hydrogen bonds form between the bases

What are the enzymes involved in semi-conservative replication?

DNA helicase and DNA polymerase

What’s the conservative model?

Original DNA molecule remains intact and a separate copy is made from completely new nucleotides

What is the semi-conservative model?

The original DNA strand splits into two, then acts as a template for each to become full strands; therefore, two new molecules both have half of the original DNA