# Science 10 reference sheet

## Genetics
- DNA bases pair A–T and C–G in the simplified double-stranded model.
- A gene is a DNA sequence; chromosomes package long DNA molecules.
- Punnett squares model allele probabilities; they do not guarantee individual outcomes.
- Natural selection changes populations across generations through differential reproductive success.

## Chemical processes
- Balance equations with coefficients, never by changing correct chemical-formula subscripts.
- In a defined closed system, mass is conserved within measurement uncertainty.
- mathrmpH=-log_10[H^+] is a useful simplified aqueous model.
- Exothermic: net energy transfer from reacting system to surroundings; endothermic: net transfer into reacting system.

## Nuclear and energy
- E_p=mgh
- E_k=frac12mv^2
- Q=mcDelta T when specific heat is approximately constant and there is no phase change.
- eta=fracE_usefulE_inputtimes100%
- Radiation risk depends on type, energy, dose/exposure, pathway, tissue, time, and shielding.

## Universe
- The Big Bang model describes an expanding, cooling universe from an earlier hot, dense state.
- z=fraclambda_obs-lambda_emitlambda_emit is a redshift measure.
- CMB, redshift/expansion, light-element abundances, and cosmic structure are independent evidence streams.

## Evidence rule
Separate observation/data from inference. State system boundaries, assumptions, uncertainty, model limitations, source/place context, and implications when relevant.
