Lo2-lo3

Life, like all material entities, is comprised of matter.

Matter is anything that has mass and occupies space.

Matter comes in varieties called

Nature produced 92 elements. Humans have made a few more

Elements come in a package called an

atom. Think of an atom as a unit quantity (e.g.,

, mg, atoms) of an element.

atom is the

smallest unit of matter that retains the properties of the element.

Proton

positively charged particle

Neutron

a particle with no charge

Electron

a particle with a negative charge

Oxygen makes up what percentage of the body?

65%

Potassium makes up what percentage of the body

.5%

Carbon makes up what percentage of the body

18%

Hydrogen makes up what percentage of the body?

10%

Sulfur makes up what percentage of the body?

0.3%

Nitrogen makes up what percent of the body?

3%

Sodium makes up what percentage of the body?

0.2%

Calcium makes up what percentage of the body?

2%

Chlorine makes up what percent of the body?

0.2%

Phosphorus makes up about \_______% of the human body.

1%

trace elements

occur in our biomass (e.g., Fe, Zn). Some elements are toxic even at trace levels (e.g., Pb, Ni).

Atoms have two general regions:

Nucleus or outer cloud

Nucleus

protons and neutrons

outer cloud

electrons

e- have relatively little mass and are moving

about the nucleus rapidly, they may be depicted as a cloud

Orbitals

are the specific volumes of space, within this cloud, where e- reside.

It is useful to depict electrons (e-) as particles within concentric

energy shells around an atomic nucleus

Max number of electrons in shell 1

2

Max number of electrons in shell 2

8

Max number of electrons in shell 3

8

Unpaired valence e- have the greatest potential to bond atoms together into molecules.

Atoms 'seek' to maximize the number e- of in their valence shells through bonding.

isotopes undergo

radioactive decay yielding energy that can be used in medical imaging

Cations

positively charged ions

Anions

negatively charged ions

• muscle contraction

(Na+, K+ and Ca2+)

neuron function

(Na+, K+ and Ca2+)

bone formation

(Ca2+)

oxygen transport

(Fe2+)

ventilation (aka breathing) homeostasis

(H+)

Compounds

are molecules with 2 or more elements.

Electrons form

the chemical bonds among atoms

Salts are bonded via

ionic bonds

Crystallization:

molecules attract to form a lattice.

Lattices can dissolve in H2O.

Some bonds dissociate in H2O.

A δ+ region of one molecule can attract to a δ- region of another molecule or ion forming a physical bond

When such a bond involves H atoms we call it a Hydrogen bond

pathway

a series or cascade of chemical reactions involved in cellular activities and systemic functions.

n biota, essentially all chemical reactions are catalyzed

by enzymes (-ase).

About a thimble's worth of water (18 ml at 4 °C to be exact) contains

6.02 x 1023 water molecules

Each water molecule continuously forms/reforms

Hydrogen bonds with about 4 neighboring water molecules.

H-bonding causes H2O molecules to

'stick' to one another (cohesion) and other molecules (adhesion).

Plants conduct water through their biomass via

capillary action; water is 'tugged' along via forces of cohesion/adhesion.

Transpiration

evaporation from planttissues, is the 'towboat' to tug on thewater pulling it in through the roots.

High specific heat capacity.

This means it must absorb a great quantity of heat (1 cal/g/°C) to raise its temperature.

Heat=

total kinetic energy

temperature

average kinetic energy

Heat in 25 °C water is transferred to ice.

The temp ↓ because ice has little kinetic energy, so average kinetic energy ↓. (However, the water now has ↑ capacity for heat because its mass ↑.)

Body fluids warm slowly because absorbed energy must first overwhelm H-bonds before

the kinetic activity/temperature can ↑ (unlike in tin man).

Freeing highly kinetic H2O molecules from H-bonds allows some to evaporate:

transforming liquid H2O → gaseous H2O.Humans use evaporative cooling via sweating to ↓ body temperature

You must ingest water and ions

(Na+, K +, Ca 2+) to replace what is lost through sweating.

Evaporative cooling works best in dry air:

evaporation rate ↓ as air humidity ↑.

Expands Upon Freezing

Water is most dense at 4 °C (1 g/ml). Its volume ↑ as it warms (one reason sea level ↑). Its volume also ↑ when its temperature ↓ below 4 °C approaching 0 °C as it freezes.

In liquid water, the action of forming/reforming H-bonds allows H2O molecules to condense like a crowd at party.

In solid water, H-bonds stabilize forming a lattice. Doing so ↑ the volume (↓ density) of the water by ∼10%.

Living cells possess as much as 70% water

by volume and can rupture/die when frozen. Biota must adapt to the cold.

Liquid water is an effective solvent

that dissolves many polar (or partially polar) bonds and dissociates salts into ions.

Water molecules form hydration shells

around ions and about partially charged molecules (opposite charge attractions).

H2O even dissolves itself (kind of) when it

ionizes into ions resulting in pH.

Aqueous solutions (aq.) have water (H2O) as a solvent.

Your body fluids are aqueous.

Solutions have various molecules, called

solutes, dissolved in them. Body fluids possess ions, proteins, acids, bases, etc.

The infant oral dose of Amoxicillin

20-40 mg/kg body weight (m/m) per day.

Human blood is

∼0.89 % (m/v) salt.

Molarity (M):

How many solute molecules (mols) found in 1 L of aq.

Percent

1 part solute: 100 parts solution

Parts per Thousand

‰1:1,000

Parts per Million

ppm 1:1,000,000

Parts per Billion

ppb 1:1,000,000,000

Parts per Trillion

ppt 1:1,000,000,000,000