DNA Packaging and Manipulation

These flashcards cover key concepts related to DNA structure, organization, molecular cloning, and anti-phage defense systems.

What are the three components of a nucleotide?

Pentose sugar (deoxyribose), phosphate, and nitrogenous base.

What types of nitrogenous bases are found in DNA?

Purines (adenine and guanine) and pyrimidines (cytosine and thymine).

What type of bond connects adjacent nucleotides in a DNA strand?

Phosphodiester bond.

How does the DNA strand polarity establish?

Polarity is established by the position of the phosphodiester bonds between the 5' phosphate and 3' hydroxyl groups.

What is the structure of the DNA double helix?

It is composed of two antiparallel polynucleotide strands with a constant diameter and twist.

How do hydrogen bonds contribute to DNA structure?

Hydrogen bonds between nitrogenous bases provide structural stability, with two bonds between adenine and thymine, and three bonds between guanine and cytosine.

What is a plasmid?

Extrachromosomal DNA that is self-replicating and inherited, found in bacteria, fungi, and some plants.

What are the differences between prokaryotic and eukaryotic chromosomes?

Prokaryotic chromosomes are circular, smaller, and located in the nucleoid, whereas eukaryotic chromosomes are linear, larger, and located in the nucleus.

What are nucleosomes?

Complex of DNA and histone proteins that appear as 'beads on a string' and play a role in DNA packaging.

What is the role of CRISPR-Cas in genome editing?

CRISPR-Cas allows targeted modifications of DNA sequences in an organism’s genome.

What is the function of restriction endonucleases in molecular cloning?

They recognize specific DNA sequences and cleave the phosphodiester backbone, creating sticky ends for DNA manipulation.

What are the steps involved in molecular cloning?

Digest DNA, anneal DNA fragments, and seal nicks in the phosphodiester backbone with DNA ligase.

What is the CRISPR array composed of?

Clustered Regularly Interspaced Short Palindromic Repeats containing repeated DNA sequences and spacers with phage DNA.

What are the steps of interference in the CRISPR-Cas system?

1. crRNA binds to Cas endonuclease. 2. crRNA base pairs with phage DNA. 3. Cas endonuclease cuts phage DNA, preventing viral replication.