DNA as an information store & packaging
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Flip to reveal answersWhere in DNA is the genetic information stored?
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All 12 Flashcards — DNA as an information store & packaging
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Question
Where in DNA is the genetic information stored?
Answer
In the **sequence (order) of the bases** A, T, C and G along the molecule.
Question
Why can DNA store so much information?
Answer
It is a **long** molecule using a **4-letter** code, so the bases can be ordered in an **enormous** number of ways.
Question
Define base sequence.
Answer
The **order of the bases** (A, T, C, G) along a DNA strand — this order is the stored information.
Question
What makes DNA a STABLE information store?
Answer
Its two **complementary strands** back each other up, and the bases sit protected inside the double helix.
Question
Define a histone.
Answer
A **protein** that **DNA wraps around** to package (condense) it inside eukaryotic cells.
Question
What do histones do?
Answer
DNA **wraps around** them to **package / condense** the long molecule so it fits inside the cell.
Question
Define a chromosome.
Answer
A single long **DNA molecule wound around histones** and condensed into a compact, organised structure.
Question
Why must DNA be packaged?
Answer
The DNA molecule is **very long** (about 2 m per human cell) but the cell is tiny, so it must be **condensed** to fit and be protected.
Question
Which organisms package DNA with histones?
Answer
**Eukaryotes** (plants, animals, fungi). Most **prokaryotes do not** use histones.
Question
Is it the number of bases or their order that stores the message?
Answer
The **order (sequence)** — rearranging the bases changes the message, like rearranging letters changes a word.
Question
How is DNA wound around histones described?
Answer
Like **thread around a spool** — the long thread winds up tightly and condenses.
Question
Do histones read or copy the DNA?
Answer
**No** — histones only **package** the DNA. Reading and copying are done by other molecules.
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Nucleic acids
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