Chapter 3
Bioenergetics
Part 1

EXERCISE PHYSIOLOGY

Introduction

•Metabolism: total of all chemical reactions that occur in the body resulting in either:

–_____________________ reactions

•Synthesis of molecules

–_____________________ reactions

•Breakdown of molecules

•Bioenergetics defined:

–Converting foodstuffs (___________________________) into energy

Energy

•We require energy in all living cells

•Each cell contains metabolic pathways that are capable of converting food (Fats, P & CHO) into _____________________.

•Example: When we move or exercise:

–Skeletal muscles continually extract energy from food consumed

–So a continuous source of energy is needed for ____________________.

–Without this continuous source, ___________________ (Just like your car stopping without gas).

Chemical Substances of Body

•Four elements (Chemical substances) make up 95% of the human body

–1. ____________ - 65%

–2. ____________ - 18%

–3. ____________ - 10%

–4. _____________ - 3%

•These elements are linked together by chemical bonds to form molecules or compounds

•Compounds can be ______________ or _____________, depending on their carbon bonds

•Fats, P & CHO contain carbon, so they are ____________

•Water does not contain carbon, so it is _____________

The Human Cell

•_________ ____________ ____________ of the Body

–Role: _____________________________________________________

•Not all cells are alike and do not perform the same function.

Figure 3.1 in your book is a hypothetical illustration made to show parts

Cell Structure
An understanding is necessary in order to understand bioenergetics

•______________________ (plasma membrane)

–Protective barrier between interior of cell and extracellular fluid

–Functions to enclose components of the cell

–Regulates passage of substances

•______________________

–Contains genes that regulate protein synthesis

–Protein synthesis determines cell composition and control of cell activity

•______________________ (in muscle, it is called _________________)

–Fluid portion of cell

–Contains organelles (__________________)

Cell Structure
An understanding is necessary in order to understand bioenergetics

•Cytoplasm

–Contains organelles (mitochondria)

–Mitochondria: Often called the __________________ of the cell.

•Involved in ________________________ of food into usable cellular energy.

•In mitochondria are ________________ that are molecules that regulate _______________ of glucose.

Structure of a Typical Cell

Introduction to Cellular Chemical Reactions

Cellular Chemical Reactions
Energy transfer in the body occurs by releasing energy trapped within chemical bonds of molecules
Cellular ________________ is a result of a series of chemical reactions

•Three types of reactions:

•1. ___________________ reactions

–Require energy to be added, yielding more energy than previously

•2. ___________________ reactions

–Release energy, as a result of chemical processes

•3. ___________________ reactions

–Liberation of energy in an exergonic reaction drives an endergonic reaction

Coupled Reactions

•Many reactions in cells are coupled

•Coupled reactions

–The liberation of ____________ energy in one reaction that __________ a second reaction

–Fig. 3.4 shows a model of this reaction

Linked reactions can be Oxidative or Reductive

Oxidative/Reduction Reactions

Oxidation - The process of ____________________ an electron from an atom.

Reduction - the _____________________ of an electron to an atom or molecule.

Coupled Reactions

The Breakdown of Glucose: An ________________ Reaction

Oxidation-Reduction Reactions

•Oxidation: removing an electron from an atom

•Reduction: addition of an electron to an atom

•Oxidation and reduction are always coupled reactions

–Molecules cannot be oxidized unless __________________________________.

•In cells, often involves the transfer of _______________ atoms rather than free electrons

–Hydrogen atom contains ________ electron

–A molecule that loses a hydrogen also loses an electron and, therefore, is ____________.

Note: Oxidized does not mean ________________ is a participant in the reaction

•Oxygen acts as a oxidizing agent by its acceptance of electrons

•Hydrogen contains one hydrogen atom and one electron.

–Molecules that gain a hydrogen atom is “reduced”.

Enzymes

•Catalysts that _________________ the ______________ of reactions

–They Lower the energy of activation

–Energy of activation is the energy required to initiate sufficient energy to proceed.

–_____________ ________________ on enzymes allow specific enzymes to adhere to a particular _______________ molecule (called a substrate).

–Like a Lock and Key scenario (Fig. 3.7)

•Factors that regulate enzyme activity

–_______________

–_______________

•Interact with specific substrates

–Lock and key model

Clinical Importance of Enzymes

The body uses CHO, P and Fat in the diet to provide

–necessary energy

–Maintain cellular activities at rest and exercise.

•During exercise, the primary energy is derived from Fats & CHO, with P contributing to a small amount of the total energy used.

Fuels for Exercise

•Carbohydrates

–_______________

•Stored as _____________

•Fats

–Primarily __________ acids

•Stored as ______________

•Proteins

–____________________ energy source during exercise

High-Energy Phosphates

•__________________ ________________ (ATP)

–Consists of adenine, ribose, and three linked phosphates (Model shown in Fig.3.8)

•Formation

•The chemical bond which joins ADP to P is called a __________ __________ ________.

•When enzyme ATPase breakes this bond, _______________ is released - resulting in energy to do work.

Structure of ATP

Model of ATP as the Universal _______________ Donor

Bioenergetics
Energy can be produced by one or a combination of 3 metabolic pathways

•1. _____________________ (ATP/PC System)

–____________________ (PC) breakdown

–Degradation of glucose and glycogen (glycolysis)

–Oxidative formation of ATP

•2. ______________________ (Glycolysis Energy System)

–Do _______ involve O₂

–PC breakdown and glycolysis

•3. ______________________ (Oxydative Energy System)

–Require O₂

–Oxidative phosphorylation

Bioenergetics
Points

•Very little ATP is stored in _______________

•Because muscle requires a constant supply of ATP to produce energy, _________________ must exist in the cell to produce enough ATP for contraction needs (or exercise needs).

Anaerobic ATP Production

•ATP-PC system - Simple __________enzyme reaction to produce ATP for ________ __________ activity

–Immediate source of ATP

Anaerobic ATP Production

•Glycolysis

The Metabolic pathway that produces ATP ____________ Oxygen (anaerobic).

It involves the breakdown of glucose or glycogen to form ___________ molecules (Pyruvate and lactic acid)

Two Phases:

–Energy ______________ phase

•Requires 2 ATP

–Energy ______________ phase

•Produces ATP, NADH (carrier molecule), and pyruvate or lactate

Glycolysis is anaerobic and occurs in the sarcoplasm of the muscle cell. It produces a net gain of 2 ATP molecules and 2 molecules of of pyruvate and lactic acid