day 4 – chapter 2 january 19 chemistry
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Day 4 – Chapter 2
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2.5 Hydrogen bonds make water cohesive.
2.6 Water has unusual properties that make it critical to life.
Cohesion
Large heat capacity
Low density as a solid
Good solvent
KNOW THESE!!!!
Cohesion
Heat Capacity
Why do coastal areas have milder, less variable climates than inland areas?
Low Density as a Solid
Why don’t oceans freeze as easily as fresh water lakes?
2.7 Living systems are highly sensitive to acidic and basic conditions.
ACID RAIN
pH Scale The amount of H+ in a solution is a
measure of its acidity and is called pH.
Acids
BasesThe pH scale is logarithmic, like the Richter Scale for earthquakes: an increase in 1 on the scale represents a ten-fold increase in the hydrogen ion concentration.
An increase of 2 represents a hundred-fold increase.
This means that Coke, with a pH of about 3.0, is 10,000 times (!) more acidic than a glass of water, with a pH of 7.0.
H+ Ions and Acids H+ very reactive
Acids can donate H+ to other chemicals
Stomach acids can kill bacteria, can bind to metals and cause them to corrode, acid rain, Coke
BasesLow H+High OH
AntacidsBaking soda, seltzer, milk of
magnesia, household cleaners
• So, now that we know life is a gentle balance of acids and bases – how does that affect the things
we eat?
Four Types of Macromolecules
Carbohydrates
Lipids
Proteins
Nucleic acids
2.8 Carbohydrates are macro-molecules that function as fuel.Health topics of
the year
Low-carb diet?
Hi-carb diet?
“Carbo-loading”?
Fiber intake?
What are carbohydrates?
Carbohydrates
C, H, and O
Primary fuel for organisms
Cell structure
Glucose Most
carbohydrates— ultimately converted into glucose
Blood sugar
More Carbohydrates
Cellulose (plant based)
Chitin (shellfish)
Fiber “Roughage”
Colon cancer prevention/reduction
Termites ecological role
Fat molecules contain much more stored energy than carbohydrate molecules.
2.15 Proteins are versatile macromolecules that serve as building blocks.
Amino Acids Twenty different amino acids
Strung together to make proteins
2.16 Proteins are an essential dietary component.
Growth
Repair
Replacement
2.17 Protein functions are influenced by their three-dimensional shape.
Peptide bonds
Why do some people have curly hair and others have straight hair?
2.19 Nucleic acids are macromolecules that store information.
Information Storage The information in a molecule of DNA
is determined by its sequence of bases.
Adenine, guanine, cytosine, and thymine
• CGATTACCCGAT
2.20 DNA holds the genetic information to build an organism.
RNA differs from DNA in three important ways.
The sugar molecule of the sugar-phosphate backbone
Single-stranded
Uracil (U) replaces thymine (T)