Molecular Organization of Chromosomes and Genomes

These flashcards cover key concepts, facts, and details related to the molecular organization of chromosomes and genomes as outlined in the lecture notes.

What is the approximate genome size of Homo sapiens?

3,000,000 thousand nucleotides.

What is the C-value paradox?

Genome sizes differ enormously among multicellular organisms with similar levels of complexity.

What type of DNA does Escherichia coli K12 have?

Circular double-stranded DNA.

What is heterochromatin characterized by?

It is highly repetitive and has low complexity, located near centromeres and telomeres.

What is the function of telomerase?

Adds telomere repeats to the ends of chromosomes.

What are IS elements in bacterial DNA?

Insertion Sequences that contain a transposase gene flanked by inverted repeats.

What are the three major components of eukaryotic DNA?

Unique sequences, highly repetitive sequences, and middle repetitive sequences.

How many copies per genome can highly repetitive sequences have?

As many as 100,000 copies per genome.

What structure do sister chromatids bind by during mitosis?

Cohesin complexes.

What component is essential for chromatin condensation during metaphase?

Condensin I.

What is the length of DNA duplex in diameter?

2 nm.

What is the structure of a yeast centromere?

It has four centromere determining elements (CDEs).

What type of sequencing takes advantage of dideoxynucleotides?

Sanger sequencing.

What is the purpose of dideoxynucleotides in DNA sequencing?

They act as chain terminators due to the lack of a 3'-OH group.

What is the approximate genome size of Saccharomyces cerevisiae?

13,000 thousand nucleotides.

What type of plasmids can be mobilized by conjugative plasmids?

Nonconjugative plasmids.

What does the term 'nucleosome' refer to in eukaryotic DNA?

The organization of DNA wrapped around histone proteins.

What is the diameter of metaphase chromatid?

1400 nm.

How does recombination occur between plasmids?

Through homologous sequences leading to formation of a cointegrate.

What is a defining characteristic of centromeres in human DNA?

They consist of a patchwork of duplicated sequences and tandem repeats.