DNA Structure, Function and Replication

A set of flashcards summarizing key concepts from a lecture on DNA structure, function, and replication, designed to aid in studying for an exam.

What is the function of DNA in organisms?

DNA contains instructions for organismal traits and stores heritable information to transmit to future generations.

What are the components of DNA nucleotides?

DNA nucleotides are composed of a 5 Carbon deoxyribose sugar, a phosphate group, and one of four nitrogenous bases.

Describe the structure of DNA.

DNA is double stranded, forms a double helix, and is composed of nucleotide monomers with strands that are antiparallel.

What are the base pairing rules in DNA?

A pairs with T and C pairs with G.

What is the role of DNA helicase during DNA replication?

DNA helicase unwinds the DNA strands by breaking the hydrogen bonds between the template strands.

What is the significance of semiconservative replication?

In semiconservative replication, each copy of DNA consists of one template (old) strand and one newly synthesized strand.

What are Okazaki fragments?

Okazaki fragments are short segments of DNA synthesized discontinuously on the lagging strand during DNA replication.

What occurs during the elongation step of DNA replication?

DNA polymerase binds and synthesizes new strands from 5’ to 3’ and RNA primers help initiate this process.

How does PCR amplify DNA?

PCR amplifies DNA by denaturing, annealing primers, and extending the new DNA strands using Taq polymerase.

What is the purpose of gel electrophoresis in confirming PCR results?

Gel electrophoresis separates DNA fragments to compare PCR products to a DNA ladder, confirming the size of the amplified DNA.

What structures protect eukaryotic DNA from degradation?

Eukaryotic DNA has telomeres at the ends, which are long nonsense DNA sequences that protect against degradation.

What is the central dogma of biology?

The central dogma describes the flow of genetic information as DNA -> RNA -> Protein.

How are DNA fragments visualized after gel electrophoresis?

DNA fragments are visualized using a dye that allows for the observation of their size after separation in the gel.

What is the name of the sequence needed to begin a new strand of DNA?

RNA primer

What molecule is needed to keep the unzipped DNA from re-annealing during replication?

Single stranded binding protein

The molecule responsible for joining the new DNA strands together after replication.

ligase