Biology Made Fun · Go Further
Unit 6: DNA, Genes & Chromosomes
The companion to Unit 6 in Biology Made Fun — the code printed on page 60, the unit's Big Picture opener. Guiding question: How does one molecule carry the instructions for a whole organism?
Animation — DNA, Genes & ChromosomesThe concept animation for this unit will be embedded here.
Key ideas from the lesson
- DNA is the molecule that carries genetic information in cells, built from subunits called nucleotides — each a sugar, a phosphate and a base.
- Its shape is the double helix: a spiral, twisted ladder whose rungs are base pairs held together by hydrogen bonds — A with T, C with G.
- A gene is a sequence of DNA that codes for a specific protein; the genetic code is the set of instructions in DNA that determines an organism's traits.
- Replication copies DNA during cell division: the helix unwinds, the strands separate like a zipper opening, free nucleotides match up with each open strand, and two new strands are built — each paired with an original.
- The result of replication is two identical DNA molecules, ready for two new cells.
Why this helps
Unit 6 asks how one molecule carries the instructions for a whole organism. Replication is the part of the answer that has to be seen: a zipper opening, bases pairing by a strict rule, and one molecule becoming two identical copies.
Try this
Write a short strand of bases — say, eight letters — then write the strand that replication would build against it, using only the pairing rule. Check your strand, then find where in the unit the same rule is used.
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