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Trace elements?
25 elements essential for life
Symptom of an iodine deficiency
Iron deficiency?
Locations and charges of protons?Neutrons?Electrons?
Atomic number
Atomic mass
Atomic Mass vs. Atomic Number?????
What is an isotope?
Cancerous throat tissue
Isotopes use to diagnose disease
Administer a molecule similar to glucose that has a radioactive tag
PET scan picks up the released radiation and detects areas of high metabolism
Urea Breath TestTests for stomach bacteria: Helicobacter pylori
Give urea with some of the carbon being 14C.
If there is Helicobacter pylori in the stomach, then this bacteria will break down the urea and produce C02.
The CO2 will be exhaled by the patient and collected in a balloon.
If some of the carbon in the exhaled CO2 contains is 14C then there must be some bacteria present in the stomach.
The more 14C exhaled, the more Helicobacter pylori present.
The breath test can be repeated to determine the success of the treatment.
Radioactive iodine
Used treat hyperthyroidism and thyroid cancer,
Small doses used to test thyroid function.
shows the concentration of radioactive tracer bound to monoamine oxidase B (MAO B). Red shows the highest concentration.
MAO B is important because it breaks down the chemicals that allow nerve cells to communicate and regulate blood pressure.
What causes an atom to react with other atom? Or… would cause it to be nonreactive (stable)?
Ionic Bond
(–) (–)
O
HH
(+) (+)
Hydrogen bond
Strong attraction for electrons
• A few water molecules can break apart into ions– hydrogen ions (H+)– hydroxide ions (OH–)
Copyright © 2009 Pearson Education, Inc.
pH
• Acids vs. bases
Copyright © 2009 Pearson Education, Inc.
pH
• A pH scale (pH = potential of hydrogen) is used to describe whether a solution is acidic or basic– pH ranges from 0 (most acidic) to 14 (most basic)– A solution that is neither acidic or basic is neutral
(pH = 7)
Copyright © 2009 Pearson Education, Inc.
Acidic solution
pH scale
Battery acid
0
1
2
3
4
5
Lemon juice, gastric juice
Grapefruit juice, soft drink,vinegar, beer
Tomato juice
Rain water
Human urine
Saliva
Pure water
6
7
Human blood,tears
Seawater
8
9
10
11
12
13
Milk of magnesia
Household ammonia
Household bleach
Oven cleaner
Neutral solution
Basic solution
NEUTRAL[H+]=OH–]
Incr
ea
sin
gly
AC
IDIC
(Hig
he
r c
on
cen
tra
tio
n o
f H
+)
14
Incr
ea
sin
gly
BA
SIC
(Lo
we
r c
on
cen
trat
ion
of
H+)
Logarithmic scaleChange in one
unit on pH scale = 10 x change in hydrogen ion concentration
Solution A has a pH = 4Solution B has a pH = 2
How much more acidic is Solution B?
Solution C has a pH = 9Solution D has a pH = 12
How much more H+ ions does solution C have compared to solution D?
Why is pH important?
• Different areas of the body have different pH values– Ex: stomach
blood
• If the pH varies from this value, proteins lose their shape and don’t work
Molecules that can accept or release H+ resist change in pH
Are usually weak acid/base pairs
Cohesion of water water sticking to itself• Does this
because of hydrogen bonding
• Results in water having surface tension– “film” on top of
water
Temperature moderation
Water resists changes in temperature
Feb: 15.7° FJuly: 70.4 ° F
Feb: 44.3° FJuly: 65.3 ° F
Water can absorb and release a lot of thermal energy with a small change in temperature
-ex: moderate temperatures at coasts
Absorbs a lot of energy when heating up
Releases energy when cooling down
ex: evaporative cooling
Adhesion water sticking to something else(polar or charged)
Meniscus
Transpiration
• Uses cohesion and adhesion to move water from the roots to top of a tree
Adhesion of waterTo cells of xylem
Cohesion of water to itself
Density Water is densest at 4° C
Ice is less dense than liquid water
Provides insulation and allows wildlife to survive under a layer of ice
Ice floats
Water is an almost universal solvent
Ionic compounds (like salt) will dissolve in water
Polar molecules will dissolve in water(sugar)
In a solution the SOLVENT is the substance in a greater amount
The SOLUTE is the substance present in a lesser amount
Glucose
Molecules that can accept or release H+ resist change in pH
Are usually weak acid/base pairs
