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)• _________ (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