Ch. 2.4 and 2.5

Section 2.4 & 2.5
What are Chemical Reactions?

Changing substances to different substances by breaking or forming chemical bonds.

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         Reactants go in        ---->       Products come out
(substances changed in reaction) --> (substances formed)

Video on Chemical Reactions
Click here

Example:

Chemical equilibrium is shown with arrows in both direction. When reactants and products are formed at the same rate.


In order for reactions to start, energy is required known as activation energy.

Some reactions release more energy than they absorb (Exothermic Reactions)

Some reactions absorb energy than they release (Endothermic Reactions) 

So why does this matter?

At this moment your body is going through many chemical reactions at a cellular level with the help ofENZYMES.

What are Enzymes?

All Enzymes are proteins but not all proteins are enzymes.

What????? It's kinda like....

Enzymes are made up of proteins. But not all proteins function as enzymes.

  How Does It Work?....

Enzymes are known as catalyst because they lower the energy needed for a reaction to take place.

Reactions happen at a faster pace with enzymes.

Check this out....

Some enzymes only work in optimal temperature and/or pH beyond that they become denatured (destroyed) 

Other enzymes break items down like Amylase in your saliva. 

 Amylase is an enzyme that catalyzes starch into sugars in your mouth.

Helpful tip: Enzymes can be identified by the ending of -ase. (ex: amylase, lipase, etc...) there are exceptions like pepsin and trypsin which are proteins used for digestion.

So how do enzymes work?....

Enzymes have a specific site where specific substances attach. So enzymes are specific kind of like a lock and key.

Enzyme structure and function — Changing the enzyme structure stops the enzyme from working properly

Substrates—reactants that bind to an enzyme’s active sites

Lock-and-key model—only certain substrates will bind to particular enzymes and allow reactions to occur  

What happens to enzymes once they complete their task? They are recycled and used again and again and again

ReviewClick here

Ch. 2.3 Biomolecules

Section 2.3

To understand basis of life we must analyze an important element at the molecular level....

  
Carbon's outermost shell can hold 8 electrons so this means carbon can bond with 4 other atoms....Carbon is unique b/c of its bonding properties.

  

Carbon has a been called the molecule of life because most living things are composed of carbon. Its atomic composition is unique and essential. The 3 basic structures of carbon-based molecules arestraight chain, branched chain, and ring. 

The 4 electrons in its valence shell (outermost shell) allow this element to covalently bond to 4 other elements including other carbons. STRUCTURE IS RELATED TO FUNCTION.


Sometimes carbon forms long chains made up of small sub-units....

Mono-mer: One subunit (1 of something)




Poly-mer: Many subunits (more than 3 of something)

There are 4 main types of carbon-based molecules found in all living things known as BIOMOLECULES....

Carbohydrates (aka sugars and starches)












Carbs are composed of 3 elements Carbon, Hydrogen, and Oxygen or (CHO) and are one of the sources for chemical energy.

Helpful tip: many science terms ending in -ose are considered carbohydrates. Ex: Glucose, Fructose, Sucrose, Cellulose.....Starch?....this is one exception. An easy way of identifying some carbs is by their ring structure

Simple carbs (monomer) are known as monosaccharides (mono=1 and saccharide=sugar)



Complex carbs (polymer) are composed of many monosaccharides linked together to form a chain .....polysaccharides (poly=many)

Glucose Song CLICK HERE





Lipids (aka fats, oil, cholesterol) 



These biomolecules are composed of Carbon, Hydrogen, and Oxygen or (CHO), but look different than carbohydrates.
Lipids are very important because they make up the membrane of your cells and are used for storing energy.

 

Helpful tip: fats can be identified by their structure....look at this


 an exception is cholesterol.... 


Proteins

These biomolecules are composed of Carbon, Hydrogen, Oxygen, and Nitrogen or (CHON)

They are composed of amino acids (monomer).

There are 22 essential amino acids all similar in structure....





            



A monomer of a protein is known as a amino acid. A polymer is known as a protein and are grouped together by bonds known as peptide bonds.





Nucleic Acids

These biomolecules are composed of Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorus or (CHONP)

The 2 examples are Deoxyribonucleic Acid and Ribonucleic Acid. Both carry genetic information

The monomer for a nucleic acid is called nucleotide and is composed of a....


A polymer looks like this.....and is called a nucleic acid

Ch.2.2 Properties of Water

H2O Vital 4 LIFE!!

Structure of Water....

How do fish survive a cold winter if their pond freezes? Most substances contract when frozen, water expands. Water is less dense as a solid (ice) than as a liquid. It acts as an insulator that allows water underneath to remain a liquid. 

What is the charge of water?

Water is known as a polar molecule because it resembles a magnet with opposite poles (charges) being on opposite sides. This allows water to form bonds with other water molecules. Remember opposites attract.

Properties of water....

Hydrogen bonds give water a high specific heat. This is an important property to have. Inside cells this property allows high energy chemical reactions to happen because these reactions produce a great amount of heat. Water absorbs this heat and helps regulate internal cell temperatures. Hydrogen bonds are formed from opposite charges of a polar molecule, like in the case of water.

Cohesion: Water molecules sticking to water molecules.

Adhesion: Water molecules sticking to different source. 

Many compounds dissolve in H2O....

Important material such as sugar and oxygen cannot be transported from one part of the organism to another without the help of a water based fluid.

Blood is made up of 95% water and carries important material all over your body.

Vocabulary to know

Solute: substance being dissolved

Solvent: substance that dissolves a solute. There is more of a solvent than a solute in a solution.

Solution: homogeneous substance formed from the dissolved solute and solvent mixture.

Where can we use this knowledge....

Some compounds release a H+ when dissolved in water (acid)

Other compounds remove a H+ from a solution (base)

Acids pH:1-6; release a H+

Neutral pH:7; neither acidic nor basic

Basic pH:8-14; remove a 

What happens if you stopped drinking water?