Theme D: Continuity and change
How life continues and changes: DNA replication and protein synthesis, mutation and gene editing, cell division and gene expression, water potential, reproduction, inheritance and homeostasis, and natural selection, ecosystem stability and climate change.
Molecules
D1.1 DNA replication
How does a cell make a faithful copy of its entire genome?
D1.2 Protein synthesis
How is a message written in DNA bases turned into a working chain of amino acids?
D1.3 Mutation and gene editing
What causes the base sequence of a gene to change, and is the change ever directed?
Cells
D2.1 Cell and nuclear division
How does one cell become many identical cells for growth and repair?
D2.2 Gene expression
How can cells with identical DNA end up doing completely different jobs?
D2.3 Water potential
What decides whether water moves into a cell or out of it?
Organisms
D3.1 Reproduction
When is copying yourself a better strategy than mixing genes with a partner?
D3.2 Inheritance
Why do offspring resemble their parents, yet never exactly?
D3.3 Homeostasis
How does the body keep its internal conditions steady when the outside world keeps changing?
Ecosystems
D4.1 Natural selection
Why do some variants leave more offspring than others, and how does that change a species?
D4.2 Stability and change
What lets some ecosystems persist almost unchanged for millions of years?
D4.3 Climate change
How do human emissions set off warming that can then feed itself?