por Carlos Perez 12 anos atrás
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Glucose becomes oxidized and Oxygen becomes reduced
Anaerobic involves respiration without oxygen
Aerobic respiration involves oxygen being consumed as a reactant along with organic fuel in respiration.
May resulte in either inhibition or stimulation of an enzyme's activity.
The binding of of an inhibitor stabilizes the inactive form of the enzyme.
The binding of an activator to a regulatory site stabilizes the shape of an allosteric enzyme that has functional actives sites.
Without regulation by enzymes, chemical traffic through the metabolism would become terribly congested because many chemical reactions take a long time.
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.
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.
Enzymes can only hasten reactions that would eventually occur anyway.
TATA Box recognized by transcription factors
Terminator sequence signals the end of transcription
Promoter sequence tells RNA Pol where to attach and initiate transcription
Transcription Factors mediate the binding of RNA polymerase and the initiation of transcription
RNA Polymerase pries two strands of DNA apart and joins together RNA nucleotides complementary to the DNA template strand, elongating the RNA polynucleotide.
occurs in nucleus
Multiple Origins of replication
Linear DNA
Replication occurs in cytoplasm
One origin of replication
Have circular DNA
Ligase joins the sugar phosphate back bones of Okazaki fragments into a continuous DNA strand
Primase synthesises primer
SSBs bond keep DNA strands from re-pairing
Topoisomerase relieves helix strain
DNA Polymerase forms a polymer of DNA in the 5'-3' direction
DNA Polymerase makes polymer of DNA and initiates DNA synthesis by adding nucleotides to a prexisting chain
Helicase separates the two strands of DNA.
This is because non-polar bonds cannot interact whereas polar bonds can due to differences in charges
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.
Deoxyribose makes it hyphilic since they are polar and can interact with water
Polynucleotides are macromolecules that exist as polymers
Polymers made up of monomers called nucleotides
nucleotides are monomers that each polynucleotide consists of
Biologically functional molecule that consists of one or more polypeptides, each folded and coiled into a specific three - dimensional structure
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.
Most biologically important
Steroids
Are characterized by a carbon skeleton consisting of four fused rings
Phospholipids
The two ends of phospholipids are different towards water.
The phosphate group and its attachments from a hydrophilic head
Hydrophobic hydrocarbon tails are excluded from water
are essential for cells because they make up cell membranes
Fats
The relatively nonpolar C-H bonds in hydrocarbon chains of fatty acids are the reason fats are hydrophillic
Constructed from 2 kinds of smaller molecules
Fatty Acid - has a long carbon skeleton, usually 16 or 18 carbon atoms in length
Glyceral - an alcohol; each of its 3 carbon bears a hydroxyl group
Consist mostly of hydrocarbon regions
Hydrophobic behavior is based on their molecular structure
Group together because they mix poorly if at all with water
Not big enough to be considered macromolecules
One class of large biological molecules that doesn't include polymers.
Polymers such as starch or cellulose form colloidal dispersions or are insoluble.
Carbohydrates are hydrophilic; the smaller carbo- hydrates, such as milk sugar and table sugar, are soluble in aqueous solution
Glucose is the most common monosaccharide and is of central importance in the chemistry of life
Dissaccharides or double sugars joined by glycosidic linkage
Simplest are monosaccharides/monomers or simple sugars
Serve as fuel and building material: include both sugars and polymers of sugars.
Polysacharrides as Macromolecules
