biochemistry | anatomy honors

Biochemistry Basics

Chemistry Review

an element can be divided.

Atoms are the smallest particle into which

the number of neutrons, not in the number of protons.

Isotopes differ from each other in

Chemical Bonds

become ions by gaining or losing electrons.

IONIC bonds are formed when atoms

There are 2 types of ions:

Cations = positive ions formed by losing electrons. (Ex) Na+

Anions = negative ions formed by gaining electrons. (Ex) Cl-Anions are named using the ending “-ide”. For example, the anion of chlorine is called chloride.

Chemical Bonds

COVALENT Bondsform when atoms share electrons. Covalent bonds are more common than ionic bonds in the molecules of living organisms.

POLAR Covalent Bond→ electrons are unequally shared by the atoms and spend more time close to one atom than the

other. As a result, slightly positive (δ+) and slightly negative (δ–) charges develop in different parts of the molecule.

NONPOLAR Covalent Bond →forms between two atoms of the same element, or between atoms of different elements that share electrons more or less equally.

(Ex) O2

Chemical Bonds

Hydrogen Bonds form because

and water molecules in particular form lots of them. Individual

hydrogen bonds are weak and

easily broken, but many hydrogen bonds together can be very strong!

hydrogen (δ+) is attracted to any neighboring negative charges. Hydrogen bonds are common,

Chemical Bonds

van der Waals forces →Simple atom Simple atom Weak forces of attraction

between electrically neutral

molecules that collide with or

pass very close to each other.

Simple atom Simple atom The van der Waals force is

caused by temporary 5 nm attractions between electron- or less

rich regions of one molecule When 2 atoms come w/in 5 nm of each other, there and electron-poor regions of will be a slight interaction between them, thus

another. causing polarity and a slight attraction.

How do various bonds work in a cell?

“Both strong and weak bonds play key roles in the chemistry of our cells and bodies.

For instance, strong covalent bonds hold together the chemical building blocks that make up a strand of DNA. However, weaker hydrogen bonds hold together the two strands of the DNA double helix. These weak bonds keep the DNA stable, but also allow it to be opened up for copying and use by the cell.

More generally, bonds between ions, water molecules, and polar molecules are constantly forming and breaking in the watery environment of a cell. In this setting, molecules of different types can and will interact with each other via weak, charge-based attractions. For instance, a Na+ might interact with a water molecule in one moment, and with the negatively charged part of a protein in the next moment.”

Both strong and weak bonds play a key role in the folding of PROTEINS!

Khan Academy

WATER

Water is able to dissolve 1000’s of

substances because it is POLAR

→slightly charged on each end.

Water covers more than 75% of

the Earth’s surface. It is the most

abundant compound in nearly all

living things!

Opposites attract!

Hydrogen Bonding

because it is POLAR.

Water is “sticky”

property of

COHESION

in the

This results

and …

ADHESION

Adhesion allows for the property

of CAPILLARY ACTION which allows blood to move through small vessels!

Water can

defy gravity!

What does CAPILLARY ACTION

have to do with the HUMAN BODY?

Water is the

“universal solvent”

due its property

of ADHESION →

Water is attracted to

other polar molecules too!

_____ tonic _____ tonic

2. 3.

A BUFFER is a solution that can maintain a nearly constant pH when Compound that releases Compound that releases

hydrogen ions (H+) into solution hydroxide ions (OH-) into solution

diluted, or when strong acids or bases are added.

Organic Chemistry EX: Water, Minerals (Calcium phosphate/bone)

Compounds that do not contain carbon

INORGANIC Compounds
ORGANICCompounds

EX: Carbohydrates, Lipids, Proteins, Nucleic Acids

Six most common elements in organic molecules:

C - H - O - N - P - S

Compounds that docontain carbon (except CO2)

CARBON is so special!

Can also form double bonds,

triple bonds, chains, and

rings.

Can form 4 single covalent

bonds; these bonds are

strong and stable.

Polymerization

Polysaccharides, Proteins, and

Nucleic acids are all polymers.

These molecules, in addition to

Lipids, are macromolecules.

(ATP & GTP are nucleoside

triphosphates that contain ribose.)

Chemical process that combines

several monomers to form a

polymer.

Dehydration Synthesis

Carbohydrates

General formula

is C(H2O)n

Sugars, starches,

cellulose

High Energy!

Glucose is made up of 6 Carbon atoms, 12 Hydrogen atoms, and 6 Oxygen atoms. The bonds present are COVALENT BONDS!

Aldehyde Aldehyde

Ketone

C6H12O6 C6H12O6 C6H12O6

Glucose is made up of 6 Carbon atoms, 12 Hydrogen atoms, and 6 Oxygen atoms. The bonds present are COVALENT BONDS!

1, 5 ether linkage

AP Bio

made?

How are

disaccharides

Polysaccharides: Starch/Glycogen

Mouth Salivary Amylase

Pancreatic Duodenum

Disaccharides

Maltose Sucrose Lactose

Small Maltase Sucrase Lactase Brush Intestine Border

Monosaccharides

2 Glucose 1 Glucose 1 Glucose AP Bio

1 Fructose 1 Galactose Does this model represent Dehydration Synthesis?

Hydrolysis

Lipids

Fats, oils, and waxes.
Lipids are compounds

made up of C, H, and

O, but often P and N.

Lipids:

o Store energy

o Form biological membranes

o Some hormones are lipids

AP Bio

What process is represented here?

closely together.

This makes

unsaturated fats

liquid at room

temperature.

Unsaturated fats

have kinks in their

hydrocarbon tails;

therefore they

cannot pack as

Oil is NONPOLAR

• Water is POLAR

OIL

“Like” dissolves “like”

WATER AP Bio Why would that be

very important in

living things?

Types of Lipids based on Structure Triglyceride

Phospholipid

| Wax | Steroid To be specific,

cholesterol is a sterol or a steroid with an –OH group | | --- | --- |

Importance of Cell Membrane Structure!

Proteins

Organic compounds composed

mainly of C, H, O, and N.

Proteins are polymers of

AMINO ACIDS, joined together

by peptide bonds.

All amino acids have a similar

chemical structure, but differ

in a region of the molecule

known as an R group.

DISULPHIDE BONDS

Disulphide bonds occur in proteins, not amino acids, although they involve a covalent bond between two amino acids (both cysteine). Disulphide bonds are used as extra stabilization of the structure of proteins. They are very important in determining the quaternary structure of some proteins. (EX) Role of disulfide bonds in the structure of antibody molecules.