18 Questions
Approximately how much DNA is present in an entire human body?
$2 \times 10^{11}$ km
What is the primary purpose of DNA supercoiling in cells?
To allow for DNA replication and transcription
What is the term for the coiling of a coil in DNA?
Supercoiling
What happens to the DNA axis when it is underwound?
It becomes more strained
What is the function of topoisomerases in DNA supercoiling?
To maintain the underwound state of DNA
What is the charge of DNA?
Negative
What is the primary reason for the negative charge of the phosphate-sugar backbone in DNA?
The presence of negatively charged phosphate groups
What is the result of DNA wrapping around a histone core?
DNA underwinding and negative supercoil
How much is DNA compacted in eukaryotic cells?
Approximately 10,000-fold
What is the structure formed by the compaction of nucleosomes?
Chromatin fiber
During which stage of the cell cycle is DNA most highly condensed?
Metaphase
What is the term for the organization of DNA and associated proteins in eukaryotic cells?
Chromatin
What is the typical size range of a prokaryotic cell?
1-10 µm
Which type of cell usually has a single chromosome and one or more plasmids?
Prokaryotic cells
What is the typical range of base pairs in a prokaryotic cell's DNA?
10^6-10^7 bp
What is the term for the compact, coiled structure of DNA in prokaryotic cells?
Supercoiling
Which type of cell typically has linear chromosomes?
Eukaryotic cells
What is the term for the bead-like structure formed by DNA wrapping around histone proteins?
Nucleosome
This quiz covers the structure and organisation of DNA, including the role of histones, nucleosomes, and chromatin fibre. It also explores the compacting of DNA and the different levels of DNA organisation.
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