Introduction to Metabolism __________ in nature – many reaction pathways the same or similar in many organisms Two general categories of organisms –_________ – use ________________ ________________________(plants, photosynthetic bacteria, etc.) –______________-________________ _______________________________ Constant _________________ between autotrophs and heterotrophs

Metabolism Is the Sum of Cellular Reactions Metabolism - the entire network of _________________ carried out by living cells _______________ - ____________ _____________ in the degradation and synthesis of polymers ___________ reactions - _______ ______________ to create smaller molecules and energy __________ reactions - ________ molecules for cell maintenance, growth and reproduction

Anabolism and catabolism

Metabolic Reactions Metabolism includes _________ __________________ reactions The metabolism of the four major groups of biomolecules will be considered: ________________ __________________

Organization of Metabolic Reactions Occur via _________ – series of organized reaction steps ___________________ – certain reactions occur in particular cells, organelles or other ___________ Pathways are _____________ – controlled –to keep anabolism and catabolism ________________________ (some use the same enzymes) –______________ to produce products only when necessary –_________________ in a pathway needs to be ________________ (________________, ______)

Types of pathways Individual reaction series –__________ (can ______ out) –____________ ______________ pathways –______________ (________) –______________ (_________)

Forms of metabolic pathways (a)Linear (or branched) (b) Cyclic

(c) Spiral pathway (fatty acid biosynthesis)

Metabolism Proceeds by ____________________ _____________ pathways permit __________________ input and output __________ multi-step pathways provide energy in _________ ________________________ _______________ in a multi-step pathway usually catalyzes only ______________ in the pathway _________________ occur in multistep pathways

Single-step vs multi-step pathways A multistep enzyme pathway releases energy in smaller amounts that can be used by the cell

Metabolic Pathways Are Regulated __________________________ Common ways to regulate (1)_________________________ (concentration) (2) _________________________ (3) Pathway __________________ _______________________

__________ of a pathway ______ ___________ of its own synthesis by _____________________ (usually the first “committed” step (unique to the pathway)

_________________________ ______________ early in the pathway _____________________ __________________ the pathway

______________________ Allosteric interactions (“______” Greek meaning “_____”; “______” meaning “________”) _________ molecule ____ to a protein at a site other than the normal binding site and regulates its activity (____________________) Modulators can be: ________ (________ a protein’s ____ when they bind) _______ (_______ a protein’s ______ when they bind) They also can be: __________ if they are the _________ the protein’s ______ (molecule that the protein normally binds) __________ if they are ____________ as the protein’s ligand An _________________ is one whose ______________________________.

______________________ for enzyme regulation _____________________ activity can be ________and ______________ by covalent modification - ____________ ______________(Example: phosphates) Protein _________phosphorylate enzymes (+ ATP) Protein _________________ remove phosphoryl groups The initial signal may be __________ _________________ of this signaling

___________________ in Pathways 1.Oxidation-Reduction (______________) 2.Making or breaking ______ ____________________ 3.Internal _______________, ____________________ or _____________________ 4.______________________ 5.______________ reactions

Redox reactions Oxidation – ___________, gain of oxygen, loss of hydrogen –Hydrogenases –Oxidases Note the different oxidation states of carbon

Carbon-Carbon Bonds ______________________ –__________ (_________ for each atom) –___________ (_______________ atom) –Recall _________ (attracted to __ charges)

Common Reaction Types Many use the ____________ _______________________  + on Carbon;  - on Oxygen –Reactive group in Aldol condensations Claisen condensations Decarboxylations

______________________ Rearrangements, isomerizations, eliminations –___________

_____________________ There are many groups to transfer –_________ –_______________ _______________ = _____

_______________ _______________________ More common than previously thought

Major Pathways in Cells __________________________ ___________________________ consumed by mammals: (1)_______________ - provide energy (2)___________- provide amino acids for protein synthesis and some energy (3)________- triacylglycerols provide energy and also lipids for membrane synthesis

Overview of catabolic pathways

________________ produces compounds for energy utilization ________________________ are produced that _________________ ____________________________ (1) __________________ (2) ____________________ (e.g. _______) (3) ___________________ (_____ ____________________)

____________________ _____________ of reduced coenzymes _____________ This produces a __________ and a __________________ _______________________ _______________________ is the process by which the __________________ the reaction: ___________________

Compartmentation and Interorgan Metabolism ____________________ of metabolic processes permits: - __________________________ within a cell - __________________________ of opposing metabolic paths - _________________________ of metabolites - ___________________________ of enzymes Example: fatty acid synthesis enzymes (cytosol) fatty acid breakdown enzymes (mitochondria)

Compartmentation of metabolic processes