Metabolism

I. The nature of energyA. 2 kinds of EB. First law of thermodynamicsC. Second law of thermodynamics

II. The nature of metabolismA. Energy changes in metabolic reactions: endergonic and

exergonicB. Metabolic pathways: 2 types

III. ATP: the main Energy carrierA. Structure and function of ATPB. The ATP/ADP cycle

IV. EnzymesA. Enzyme structure and functionB. Effects of temperature and pH on enzymes

V. Cell Membranes

I. The nature of energyA. 2 kinds of EB. First law of thermodynamics

A. 2 kinds of energy

potentialkinetic

B. First law

Energy cannot be created or destroyed.

Implications of First Law:

1. The energy of the Universe is a constant.

2. The energy of the Universe has existed forever.

C. Second law of thermodynamics

Entropy: a measure of disorganization in a system

Closed system: no energy input from outside sourceOpen system: receives energy input from outside source

One way flow: in as light energy– out as heat energy

*Kinetic energy = Heat energy + Free Energy

In every energy exchange, there is a loss as heat energy.Heat energy is a loss because it cannot do the work of the cell.

Energy flow through anEcosystem.

Primary producers get the energy first and convert it into chemical energy on which the rest of the ecosystem depends.

Transfer: 90% loss – 10% capture

II. The nature of metabolism

A. Energy changes in metabolic reactions: endergonic and exergonic

B. Metabolic pathways: 2 types

E in endergonic

E outexergonic

Exergonic graph?

B. Metabolic pathwaysCatabolism: break down

Anabolism: synthesis

coupled rx

A-B A + B

A + B A-BEnergy from exergonic rx used to drive endergonic rx.

A cow must eat at least 100 pounds of grain to gain less than 10 pounds of muscle tissue. This illustrates a. the first law of thermodynamics. b. the second law of thermodynamics. c. that some energy is destroyed in every energy conversion. d. that energy transformations are typically 100% efficient.

Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing

a. chemical energy into potential energy. b. kinetic energy into chemical energy. c. chemical energy into kinetic energy. d. kinetic energy into potential energy.

The energy available to do work isa. free energyb. kinetic energyc. heat energyd. potential energy

Which of the following is correct?a. kinetic energy = potential energy + heat energyb. kinetic energy = free energy + potential energyc. kinetic energy = free energy + heat energyd. kinetic energy = kinetic energy + free energy

Which one of the following processes is endergonic? a. the synthesis of glucose from carbon dioxide and water b. the release of heat from the breakdown of glucose c. the breakdown of glucose to power ATP formation d. the burning of wood

Reasons why ATP is such a good energy carrier

1. Small • easily stored• mobile

2. Easily regenerated

3. Energy transferred• phosphorylation

4. Energy transferred is roughly the amount needed

III. ATP: the main energy carrier

III. ATP: the main energy carrier

Loss of heat energy!!!!(e.g. digestion)

III. ATP: the main energy carrierWork of the Cell

Photosynthesis and respiration

PS: anabolicRS: catabolic

The products of ps are the reactants of rs.

Glucose = potential energy

In RS, the potential energy of glucose is converted into the potential energy of ATP which can then be hydrolyzed to provide free energy for cellular work.

They are coupled reactions!

Which of the following is NOT a reason why ATP is such a good energy carrier?a. ATP is small and thus easily storedb. ATP is easily regeneratedc. The energy from ATP can be transferred d. ATP converts potential energy into free energye. The energy released by ATP is roughly equivalent to that which is needed.

Which of the following is NOT a correct statement?a. Photosynthesis and respiration are coupled reactionsb. Photosynthesis is anabolic and respiration is catabolicc. The products of respiration are the reactants of photosynthesisd. Plants do both photosynthesis and respiration

IV. EnzymesFacilitate metabolic reactions

Neutralize toxins

Enzymes work by lowering the energy barrier required for reactions to take place.

Many reactions would go without enzymes, but would use too much energy and take too much time.

(substrates)

IV. EnzymesA. Enzyme structure and function

Catabolic or anabolic?

Hydrolysis or dehydration synthesis?

(- ase ending)

Enzyme control and inhibition

Feedback inhibition

Feedback inhibition site

Effect of temp and pH on enzyme activity

Enzymes are denatured at high temperature and high and low pH.

What do enzymes NOT do?a. Use potential energy to break chemical bondsb. Convert products into reactantsc. Convert reactants into productsd. Lower the activation energy required for chemical reactions to go.e. Detoxify toxins

Which of the following conditions does NOT result in enzyme denaturation?

a. very high temperature away from optimumb. very low temperature away from optimumc. very high pH away from optimumd. very low pH away from optimum

An enzyme that is exposed to high heat far from its optimum activation temperature experiences the breakage of what type of bonds?

a. Covalentb. Hydrogenc. Ionicd. Peptide

V. Cell membranes: anatomy and physiology

A. Membrane structure and function 1. main components: phospholipids and proteins

Phospholipid bilayer

ECF/ ICF(extracellular fluid/ intracellular fluid)

Hydrophobic barrier

2. Fluid Mosaic Model

Roles of proteins

Self- antigens

B. Movement across the membrane

1. passive transport: diffusion and osmosis2. active transport

Solutes, solvents, solutions

Movement of like species from area of high concentration to low [ ]

Passive transport requires no energy

Only requirement is for a [ ] gradient

Facilitated diffusion uses transport proteins to effect passive transport of ions and polar molecules.

1. passive transportOsmosis = movement of a solvent from area of low [solute] to high [solute] across a differentially (selectively) permeable membrane

Hypotonic, hypertonic, and isotonic solutions

2. active transportRequires energy and protein pumps

ATP

Movement is with disregard to the [ ] gradient

Transport summary

What does the phospholipids bilayer create?a. a passage for polar substances into the cellb. a hydrophilic environment to separate the ECF and ICFc. a barrier to the movement of cholesterold. a hydrophobic barrier to the movement of charged compounds

What is always necessary for passive transport to take place?

a. energy from ATPb. transport proteinsc. ions or polar moleculesd. a concentration gradient

Under which of these conditions will water move into a cell?a. cell is in isotonic solutionb. cell is in hypertonic solutionc. cell is in hypotonic solutiond. none of these

3. Cellular communication

Signal transduction

4. Electron transport systems

Electron donor

Final electron acceptor

The end