MetabolismMetabolismBiology 1114

EnergyEnergy

• Capacity to Do Work• Calories / Joules• 1 calorie = 4.184 Joules• Biologists Use Calories• Physicists and Chemists Use Joules

Cells Require EnergyCells Require Energy

• Phototrophs• Chemolithotrophs• Chemoorganotrophs

• Activation Energy is the additional energy required for a particular process to occur

AnabolismAnabolism• Make New Molecules• Simple to Complex• Assimilative• Biosynthetic• Endergonic

Metabolism is the Sum Total of all the Chemical Reactions Within a Living Organism.

CatabolismCatabolism• Used to Obtain Energy• Complex to Simple• Degradative• Dissimulative• Exergonic

Metabolism is the Sum Total of all the Chemical Reactions Within a Living Organism.

The Earth’s Energy Comes From the SunThe Earth’s Energy Comes From the Sun

ATPATP

• 1 Adenine

• 3 Phosphates

• Ribose

The universal energy carrying molecule in living organisms.

The terminal 3The terminal 3rdrd Phosphate bond is a special high-energy bond. Phosphate bond is a special high-energy bond.

Function of MitochondriaFunction of Mitochondria• Glucose Enters Mitochondria which is filled with

ADP• Glucose Bonds are Broken and Energy is Released• This Energy is Used to Add the Third Phosphate to

ADP• This Process is Phosphorylation• ATP Travels to Wherever Energy is Needed• Third Phosphate is Cleaved and Energy is

Released• ADP Returns to Mitochondria• Process Begins Again

PhosphorylationPhosphorylation

The Principle The Principle of Molecular of Molecular RecognitionRecognition

• Living Organisms are Very Complicated• High Level of Regulation is Necessary• Regulation is Achieved Through Recognition• Recognition Causes a Preprogrammed Response

Sound Stimuli/Recognition Leads to Response

Visual Stimuli/Recognition Leads to Response

The Principle of Molecular The Principle of Molecular RecognitionRecognition

• Specialized Cells• Binding by Ligands to

Receptors• Message Transfer to

the Cell’s Interior• Control Center

Initiates a Response

Metabolic PathwaysMetabolic PathwaysEnergy is passed from one molecule to another via metabolic Energy is passed from one molecule to another via metabolic pathwayspathways

• Definition– An ordered series of chemical reactions

• Mediated by Enzymes– Proteins that catalyze chemical reactions by lowering

activation energy– Large proteins with a characteristic three dimensional shape

• The Tools of Life– Have one specific job to do and are very efficient– Operate at normal to low temperatures– Catalysts that can be reused again and again

Enzymes catalyze chemical reactions by lowering the activation energy required for the reaction to occur.

So How Might a So How Might a Diet Pill Work?Diet Pill Work?

What is the problem with this?

EnzymesEnzymes• End in ASE• Named by Substrate or Chemical Reaction• Proteases• Lipases• DNAses• Lactase• Glucokinase

There are six classes of enzymes and these are defined on the basis of the type of reaction they catalyze

Enzyme ComponentsEnzyme Components

Enzyme CharacteristicsEnzyme Characteristics

• Organic Catalysts

• Renewable

• Large

• Work Quickly

• Stable and Long Lasting

• Unique Functional Structure

Lock and Key ParadigmLock and Key Paradigm

1. Interaction Between Enzyme and Substrate

2. Initiates a Preprogrammed Reaction

3. Causes Substrate Transformation

DenaturationDenaturation

• 12:50 2001-02-27

• Child survives after being dead for 90 minutes •

A 13-month-old female toddler who had wandered out through an open kitchen door, was found lying face-down in the snow, in temperatures of about minus 4 degrees Fahrenheit (minus 20 Celsius) on Saturday. She was wearing only a diaper. Her heart stopped beating for more than 90 minutes, but she suffered no brain damage and is now recovering in the Edmonton hospital where she was treated for extreme hypothermia. Police, who declined to give her name, believe she may have become disoriented after leaving the bed in which she has been asleep with her mother. The 26-year-old mother, who had gone to bed around 10 p.m., awoke about 3 a.m., found the toddler missing, and began a frantic search.

• Outside, she followed the child's footprints and found her lying frozen in the snow. Paramedics, who arrived after a 911 emergency call, found she had no pulse. At the University of Alberta Hospital, doctors put her in a "bear hug" blanket to circulate warm air around her body and raise her body temperature, but normal medical procedures failed to get her heart beating again. Doctors were about to begin surgery to put her on a heart-lung machine when, just before 5 a.m., they were astonished to find the baby's heart began beating again on its own. There have been four or five other documented cases of very small children surviving after been frozen in sub-zero weather conditions, doctors are quoted by UPI as saying.

• On May 30, 2002, a 30-year old landscape mowing assistant collapsed and died at the end of a day of caring for residential lawns. A typical day’s work consisted of mowing, edging, trimming with a weed whip, and finishing with a back-pack blower. His partner, the leader of the two-man crew, witnessed his collapse and immediately called for help. Emergency medical assistance responded and he was transported to the hospital where he was pronounced dead. At the hospital, a rectal temperature of 107.6 degrees Fahrenheit was recorded.

Factors Influencing Enzymatic ActivityFactors Influencing Enzymatic Activity

1. Temperature

2. pH

3. Concentration

InhibitionInhibition

In the brain there exists an important system-wide regulatory center known as the hypothalamus. The hypothalamus synthesizes and releases a hormone called thyrotropin-releasing-hormone (or TRH). The release of TRH by the hypothalamus causes release of thyrotropin-stimulating-hormone (or TSH) by the nearby pituitary gland. TSH from the pituitary travels via circulation to the thyroid tissues and is the most significant factor for stimulating the synthesis and release of biologically active thyroid hormone molecules. The hypothalamus is also sensitive to levels of TSH; when TSH levels are increased, there is feedback of this information to the hypothalamus resulting in the cessation of further synthesis and release of more TRH

Example of Feedback Inhibition