Biology 311C

BIG IDEA I: STRUCTURE RELATES TO FUNCTION

3A: Biological Molecules

Carbohydrates

Polysacharrides as Macromolecules

Serve as fuel and building material: include both sugars and polymers of sugars.

Simplest are monosaccharides/monomers or simple sugars

Dissaccharides or double sugars joined by glycosidic linkage

Carbohydrates are hydrophilic; the smaller carbo- hydrates, such as milk sugar and table sugar, are soluble in aqueous solution

Polymers such as starch or cellulose form colloidal dispersions or are insoluble.

Lipids

One class of large biological molecules that doesn't include polymers.

Not big enough to be considered macromolecules

Group together because they mix poorly if at all with water

Hydrophobic behavior is based on their molecular structure

Consist mostly of hydrocarbon regions

Most biologically important

Fats

Constructed from 2 kinds of smaller molecules

Glyceral - an alcohol; each of its 3 carbon bears a hydroxyl group

Fatty Acid - has a long carbon skeleton, usually 16 or 18 carbon atoms in length

The relatively nonpolar C-H bonds in hydrocarbon chains of fatty acids are the reason fats are hydrophillic

are essential for cells because they make up cell membranes

The two ends of phospholipids are different towards water.

Hydrophobic hydrocarbon tails are excluded from water

The phosphate group and its attachments from a hydrophilic head

Steroids

Are characterized by a carbon skeleton consisting of four fused rings

Unbranched polymers constructed from the same set of 20 amino acids

Polymers of amino acids are called polypeptides

An amino acid is an organic molecule posessing both an amino group and a carboxyl group.

Biologically functional molecule that consists of one or more polypeptides, each folded and coiled into a specific three - dimensional structure

Nucleic Acids

Polymers made up of monomers called nucleotides

nucleotides are monomers that each polynucleotide consists of

Polynucleotides are macromolecules that exist as polymers

2B: Chemistry for Biology

The formation of hydrogen bonds is important in biological systems because the bonds stabilize and determine the structure and shape of large macromolecules such as nucleic acids and proteins.

This is because non-polar bonds cannot interact whereas polar bonds can due to differences in charges

BIG IDEA III: GENETIC INFORMATION IS TRANSMITTED THROUGH GENERATIONS AND EXPRESSED IN A REGULATED MANNER.

Enzymes in Repiication

Helicase separates the two strands of DNA.

DNA Polymerase makes polymer of DNA and initiates DNA synthesis by adding nucleotides to a prexisting chain

DNA Polymerase forms a polymer of DNA in the 5'-3' direction

Topoisomerase relieves helix strain

SSBs bond keep DNA strands from re-pairing

Primase synthesises primer

Ligase joins the sugar phosphate back bones of Okazaki fragments into a continuous DNA strand

Prokaryotes

Have circular DNA

One origin of replication

Replication occurs in cytoplasm

Eukarytoes

Linear DNA

Multiple Origins of replication

occurs in nucleus

Enzymes for Transcription

RNA Polymerase pries two strands of DNA apart and joins together RNA nucleotides complementary to the DNA template strand, elongating the RNA polynucleotide.

Proteins for Transcription

Transcription Factors mediate the binding of RNA polymerase and the initiation of transcription

DNA Sequences for Transcription

Promoter sequence tells RNA Pol where to attach and initiate transcription

Terminator sequence signals the end of transcription

TATA Box recognized by transcription factors

BIG IDEA II: ENERGY IS STORED, USED AND TRANSFORMED IN LIVING SYSTEMS

8D: Metabolism

Enzymes speed up metabolic reactions by lowering energy barriers

An enzyme catalyzes a reaction by lowering the activation energy barrier, enabling the reactant molecules to absorb enough energy to reach the transition state even at moderate temperatures.

An enzyme cannot change the free energy for a reaction; it cannot make an endergonic reaction exergonic.

Enzymes can only hasten reactions that would eventually occur anyway.

Because enzymes are very specific for the reactions they catalyze, they determine which chemical processes will be going on in the cell at any particular time.

An enzyme is a macromolecule that acts as a catalyst, a chemical agent that speeds up a reaction without being consumed by the reaction.

Without regulation by enzymes, chemical traffic through the metabolism would become terribly congested because many chemical reactions take a long time.

Substrates bind to active site of an enzyme causing catalysis to occur.

Allosteric regulation is the term used to describe any case in which a protein's function at one site is affected by the binding of a regulatory molecule to a separate site.

The binding of an activator to a regulatory site stabilizes the shape of an allosteric enzyme that has functional actives sites.

The binding of of an inhibitor stabilizes the inactive form of the enzyme.

9A: Respiration

Organic Compounds + Oxygen => Carbon Dioxide + Water + Energy

Cellular respiration is the catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP.

Aerobic respiration involves oxygen being consumed as a reactant along with organic fuel in respiration.

Anaerobic involves respiration without oxygen

Carbohydrates, fats, and protetins can all be processed and consumed as fuel, although Glucose is the fuel that cells most often use.