Day 4 – Chapter 2

Power Up your Clicker!Some notes on

biologywithtechnology.com

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)