AP BIO: Chemistry of life

unit 1 test...

Covalent bonds

when two or more atoms share

electrons (usually between two nonmetals)

Nonpolar covalent:

Electrons are shared equally between two atoms

Polar covalent

Electrons are not shared equally between two atoms

ex: oxygen is negative charges & Hydrogen is positive

Ionic bonds

The attraction between oppositely charged atoms (ions)

Hydrogen bonds

the partially positive hydrogen atom in one polar covalent molecule will be

attracted to an electronegative atom in another polar covalent molecule

Polarity

polar covalent bonds created by unequal sharing of electrons between oxygen and

hydrogen within the molecule of water

Cohesion

attraction of molecules or other molecules of the same kind

-Allows for the transport of H2O and nutrients against gravity in plants

ex:H2O toH2O

Adhesion

the attraction to other molecules that are polar or have charge

-In plants, this allows water to

cling to the cell walls to resist

the downward pull of gravity

Capillary Action

the upward movement of water due to the forces of cohesion, adhesion, and surface tension

- Occurs when adhesion is greater than cohesion

-Important for transport of

water and nutrients in plants

Functional groups

chemical groups attached to the carbon skeleton that participate in chemical reactions

ex:Amino acid group,Carboxyl group,hydroxyl group etc

Macromolecules

• Carbohydrates 

• Proteins 

• Nucleic Acid 

• Lipids 

Polymers

chain like macromolecules of similar or identical repeating units that are covalently bonded together

Monomers

the repeating units that make up

polymers

Dehydration reaction

covalently bonds two monomers with the loss of H2O

ex:AB + H2O → A+B

Hydrolysis

breaks the covalent bonds in a polymer by adding H2O

ex:AB + H2O → A+B

Carbohydrates

Composed of C,H,& O

Includes sugars and polymers of sugars

-contains a hydroxyl and carbonyl group

Carbohydrate Monomer

Monosaccharide

Carbohydrate Polymer

polysaccharide

Examples of Carbohydrates

Glucose,fructose,and sucrose

Dissaccharides

Two monomers

ex:sucrose 

bond:Glycoside linkage 

Polyssaccharides

polymers with many sugars

Carbohydrate structural

Cellulose: Found in plant cell walls 

Chitin: Forms exoskeleton of arthropods 

Carbohydrate storage

Starch: Found in plants 

Glycogen: Found in animals 

Proteins 

composed of C,H,O,N,& S 

molecule consisting of polypeptides,folded into 3D shape 

-shape determines function 

Bond: peptide bond (between Carboxyl & amino acid )

Protein Monomer

Amino Acid

Protein Polymer

Polypeptide

Primary Structure

Bond: peptide bonds between amino acids

structure: string of amino acids 

Secondary Structure

Bond: Hydrogen bonds between backbone

Structure: alpha helix or beta pleated sheet

Tertiary Structure

Bond: Any (Hydrogen,Covalent,Ionic) between R groups 

structure:  Final 3D structure 

Quaternary

Bond: Any (Hydrogen,Covalent,Ionic) between R groups or different polypeptides 

Function of proteins

• Antibody-help protect the body from disease

• Enzyme- carry out chemical reactions or assist

• in creating new molecules

• Messenger- transmit signals (ie hormones)

• Structural- provide structure and support

• Transport/storage- bind to and carry small

• atoms and molecules through the body

Nucleic Acid

Composed of C,H,O,N,& P

-Polymers made of nucleotide monomers

Directionality 5’—> 3’ ; anti-parallel

TWO FORMS:DNA & RNA

Nucleic Acid monomers

Nucleotide

Nucleic Acid Polymer

DNA & RNA

Nucleic Acid Function

Store,transmit,& express heredity info

Purines 

Double ring (A & G) 

Pyrimidine 

single ring (C,U,T)

Lipids

Composed of C,H,O,& P

Class of molecules that do not include true polymers 

*ALL LIPIDS ARE NON-POLAR (aka hydrophobic) 

Types of Lipids

• Fats

• Phospholipids 

• Steroids 

• Cholesterol 

Function of Lipids

1. Provide energy storage

2. support cell function 

3. provide insulation to keep mammals warm 

Lipids Monomer

Glycerol: classified as an alcohol 

Fatty acid: long carbon chains 

*LIPIDS HAS NO POLYMERS 

Saturated fatty acid 

all single bonds

-each carbon is saturated by hydrogen 

unsaturated fatty acid

at least one double bonds

-Not all carbons are saturated by hydrogen 

Phospholipids

Major component of cell membrane 

-TWO fatty acids attached to a glycerol and a phosphate 

Hydrophillic head (attracted to water )

Hydrophobic tail (repelled by water) 

Steroids 

hormones that support physiological functions like growth, development, energy,metabolism, and homeostasis 

ex: testosterone, or estrogen  

Cholesterol

Provides structural stability to animal cell membranes