1 Physical Foundations for Biology and Medicine Free Online FlashCards

What makes a numerical measurement a physical quantity?

A physical quantity is a measurable property expressed as a number multiplied by a unit; the unit gives the number its meaning.

Which seven units are the SI base units?

The seven SI base units are the meter, kilogram, second, ampere, kelvin, mole, and candela.

What is the SI unit of pressure, in base units?

Pressure is force per area: its SI unit is the pascal, equivalent to $\text{N}/\text{m}^2$ or $\text{kg}\cdot\text{m}^{-1}\cdot\text{s}^{-2}$.

How does a milligram compare with a microgram?

A milligram is $10^{-3}$ grams and a microgram is $10^{-6}$ grams, so a milligram is one thousand times larger.

What does dimensional analysis check in an equation?

Every term in a valid equation must have compatible dimensions; for example, pressure cannot be added to velocity.

How should reported precision reflect measurement uncertainty?

Report precision in a way that reflects the measurement’s uncertainty, rather than implying more certainty than the instrument supports.

How do surface area and volume scale with length factor $k$?

If a structure’s length scales by $k$ while shape stays the same, surface area scales by $k^2$ and volume by $k^3$.

What do the terms in the allometric relationship $y=aM^b$ represent?

In $y=aM^b$, $M$ is a size measure, $y$ is the trait, $a$ is a fitted coefficient, and $b$ is the scaling exponent.

Is an allometric exponent universal across biological traits?

No: the exponent must be estimated for the population and trait studied; biological scaling relationships are not necessarily universal.

What are the main steps in building and checking a physical model?

Define the system and question, choose variables and scales, state assumptions, select governing relationships, check dimensions and limiting cases, then compare predictions with measurements.

Why must a physical model state its assumptions?

Assumptions simplify analysis but limit where the model’s results apply; they should suit the question being asked.

How does a distributed model differ from a lumped model?

A lumped model uses a few average variables; a distributed model represents how quantities vary over space or time.