The Chemistry of Life

Bio 100

Tri-County Technical College

Pendleton, S. C.

Basic Beginnings

Flow chart for lifeBiosphereecosystemcommunity

Populationorganismorgan systemOrgantissuecellorganellemolecule

atomsubatomic particleswho knows?

Biochemistry

The study of the chemistry associated with living system.

Much of this chemistry involves compounds containing carbon.

Carbon can form four single bonds. Carbon can also form double covalent

bonds and triple covalent bonds

Chapter 3; Continued Hydrocarbon contains only carbon and

hydrogen atoms (methane, ethane, etc.) Functional group is group attached to

hydrocarbon skeleton that makes it more (or less) reactive

Hydroxyl, carbonyl, carboxyl, amino, phosphate, sulfhydryl, and methyl

Review: remember polar and those highly electronegative atoms we discussed earlier

Single Bonds

involves sharing two electrons represented by a single line in a

structural formula methane is an example -- CH4

Double Bonds

involves sharing four electrons represented by two lines in a structural

formula the carboxyl group is an example double bond between carbon and

oxygen.

Triple Bond

involves sharing 6 electrons represented by 3 lines in a structural

formula

What it are?

Macromolecule is giant molecule of living matter formed by the joining of smaller molecules

A monomer is an identical or similar repeating subunit

A polymer is composed of monomers Monomer + monomer = dimer For our course, more than 2 monomers

joined together will equal a polymer (NOT entirely true…but will do)

Synthesis and Hydrolysis

Many biologically important compounds are polymers.– composed of many monomers– for example starch is a polymer of glucose

Synthesis is the process by which individual glucose molecules are put together to form the starch.

Synthesis

molecule of water is removed between two monomers

bonds that are left are used to make a bond between the monomers

Also called condensation reaction

Hydrolysis

the opposite of synthesis molecule of water added across a bond bond is split Learn to look for where the water is

located To right of the arrow = synthesis To left of arrow = hydrolysis

Biochemical Molecule Categories

Carbohydrates– monosaccharides and polysaccharides

Lipids– steroids, neutral fats, phospholipids

Proteins– dipeptides, tripeptides, polypeptides

Nucleic Acids– DNA and RNA

Carbohydrates

Carbohydrates

composed of C, H, and O monosaccharides

– C1H2O1

– ribose for example: C5H10O5 (pentose)

– hexose for example: C6H12O6 (hexose)

– Glucose is a hexose» blood sugar

Disaccharides composed of two monosaccharides sucrose -- table sugar -- C12H22O11

– water removed during synthesis– 1 glucose and 1 fructose

lactose -- milk sugar – 1 glucose and 1 galactose

maltose -- malt sugar– two glucose molecules

Polysaccharides

composed of many monosaccharides examples

– starch– glycogen– cellulose

all three composed of glucose different ways of putting the glucose

together

Lipids

Triglycerides

composed of one glycerol molecule and three fatty acids

also called neutral fats circulate in bloodstream fatty acids are long chains of carbon

with a carboxyl group at one end

Saturated vs. Unsaturated

Saturated fats– contain fatty acids saturated with hydrogen

atoms– no double bonds in the fatty acids

Unsaturated fats– contains fatty acids not saturated with

hydrogen atoms– have double bonds in the fatty acids

Phospholipids

one fatty acid in a triglyceride is replaced by a phosphate group.

one end is soluble in water– hydrophilic end

other end is insoluble in water– hydrophobic end

major component of cell membranes

Steroids

Cholesterol and the other steroids made from it

Basic steroid ring structure Steroid hormones

– produced by the adrenal and other glands

Proteins

Building blocks are amino acids.

Amino acids

There are 20 amino acids that the human body has to have.

All of them– amino group– carboxyl group– R-group

The R-group makes each one unique.

Peptide Bonds

Bonds between the amino acids in a protein.

Formed between an amino group and a carboxyl group

A molecule of water is removed each time a peptide bond is formed

dipeptides, tripeptides, and polypeptides

Other proteins?

Two primary categories of proteins– structural– functional

Enzymes are functional proteins Structural protein examples

– muscle protein– tendon protein, etc.

Nucleic Acids

DNA and RNA

Nucleotides

Building blocks of DNA and RNA composed of sugar, phosphate and a

base The sugar and the bases of DNA are

different from those of RNA. The phosphate group is the same in

both.

DNA-nucleotides

Sugar– deoxyribose– one less oxygen than ribose

DNA bases– adenine– thymine– guanine– cytosine

RNA-nucleotides

Sugar– ribose

Bases– adenine– uracil– guanine– cytosine

What do they do?

DNA– contains the blueprint for making all the

proteins of a cell– makes up genes and chromosomes

RNA– takes the blueprint from DNA and

translates it into proteins

Believe me, it matters

Hydrophilic means water loving Hydrophobic means water fearing

(hating) Life as we know it depends on interplay

between hydrophobic and hydrophilic parts of phospholipids (and others)

Review: polar and nonpolar and water as a polar molecule

Polar = hydrophilic