CELL PHYSIOLOGYCELL PHYSIOLOGYand and

CELLULAR CELLULAR METABOLISMMETABOLISM

CELL PHYSIOLOGYCELL PHYSIOLOGY

The the processes or functions of the cellThe the processes or functions of the cell

CELL TRANSPORT2 ways that the molecules move through the

membrane: 1. Active transport requires that the cell use

energy that it has obtained from food to move the molecules (or larger particles) through the cell membrane.

2. Passive transport does not require such energy expenditure, and occurs spontaneously

PASSIVE TRANSPORTPASSIVE TRANSPORT ACTIVE TRANSPORTACTIVE TRANSPORT- Does not require energy- Does not require energy

- Does not require oxygen- Does not require oxygen    -flow of materials is from flow of materials is from greater to lesser greater to lesser concentration(follows concentration(follows concentration gradient)concentration gradient)

- flow rate is slower - flow rate is slower

- examples:- examples:

DiffusionDiffusion,,SelectivelySelectively permeable membranes permeable membranes , ,OsmosisOsmosis (isotonic, hypotonic (isotonic, hypotonic and hypertonic solutions)and hypertonic solutions)

Facilitated diffusionFacilitated diffusion

- requires for energy- requires for energy

- requires oxygen- requires oxygen

- flow of materials is from - flow of materials is from lesser to greater concentration lesser to greater concentration (does not follow concentration (does not follow concentration gradient)gradient)

- flow rate is faster- flow rate is faster

- examples:- examples:

    EndocytosisEndocytosis

PhagocytosisPhagocytosis

PinocystosisPinocystosis

ExocytosisExocytosis

SOLUTION, SOLVENT AND SOLUTION, SOLVENT AND SOLUTESOLUTE

A A solutionsolution is a homogenous molecular mixture of two or more is a homogenous molecular mixture of two or more substances. substances.

The substance that has the greatest concentration is the The substance that has the greatest concentration is the solvent. It is the substance that dissolves the other substance(s) solvent. It is the substance that dissolves the other substance(s) in the solution. in the solution.

Substances that are found in lesser concentration in solutions Substances that are found in lesser concentration in solutions are are solutessolutes. Solutes are the substances dissolved by solvents.. Solutes are the substances dissolved by solvents.

When you put a spoonful of sugar in a cup of water, the result When you put a spoonful of sugar in a cup of water, the result is a solution. The water is the is a solution. The water is the solventsolvent and the sugar is the and the sugar is the solute. Suppose you have a cup of coffee with sugar in it. solute. Suppose you have a cup of coffee with sugar in it. __________ is the solvent and _________ and __________ __________ is the solvent and _________ and __________ are the solutes. are the solutes.

DIFFUSIONDIFFUSION

The principle means of passive transport The principle means of passive transport DiffusionDiffusion - The random movement of - The random movement of

molecules from a area of higher concentration molecules from a area of higher concentration to an area to an area

of lower concentration. of lower concentration. the direction of diffusion is determined by the the direction of diffusion is determined by the

concentration of specific molecules in concentration of specific molecules in the two sides of the membrane and the energy the two sides of the membrane and the energy

that causes the diffusionthat causes the diffusion

DIFFUSIONDIFFUSION

It is important to bear in mind that:    - the movement is random    - the steeper the concentration gradient (ie. the bigger the difference between the higher concentration and lower concentration), the faster will be the movement.

TYPES OF DIFFUSIONTYPES OF DIFFUSION

1.1. SOLID OVERSOLID OVERa. solid - MASTICATIONa. solid - MASTICATION

b. liquid - DIGESTIONb. liquid - DIGESTIONc. gas - TRANSPIRATIONc. gas - TRANSPIRATION

2. LIQUID OVER2. LIQUID OVERa. solid - PERSPIRATIONa. solid - PERSPIRATION

b. liquid -DIGESTIONb. liquid -DIGESTIONc. gas - EVAPORATIONc. gas - EVAPORATION

3. GAS OVER3. GAS OVER a. solid - SUBLIMATIONa. solid - SUBLIMATION b. liquid - OXYGENATIONb. liquid - OXYGENATION c. gas - RESPIRATIONc. gas - RESPIRATION

DIFFUSION OF SOLID OVER DIFFUSION OF SOLID OVER LIQUIDLIQUID

What factors can influence the rate of What factors can influence the rate of diffusion?diffusion?

Temperature. Temperature. The state of the solvent; i.e. whether the solvent is a solid, The state of the solvent; i.e. whether the solvent is a solid,

liquid or gas. liquid or gas. The size of the molecules. The size of the molecules. The steepness of the diffusion gradient. The steepness of the diffusion gradient. PermeabilityPermeability Size of moleculesSize of molecules Size of poresSize of pores SolubilitySolubility Electrical chargesElectrical charges Membrane structureMembrane structure

Property of DiffusionProperty of Diffusion

The greater the space between these molecules The greater the space between these molecules the greater the ability for the molecular the greater the ability for the molecular particles to spread out from one another. particles to spread out from one another.

The more packed the molecules are in the The more packed the molecules are in the substance the less space to maneuver, and substance the less space to maneuver, and therefore, the more difficult for diffusion to therefore, the more difficult for diffusion to occur.occur.

Requires diffusion pressureRequires diffusion pressure

OSMOSISOSMOSIS is the is the movement of water moleculesmovement of water molecules from a region of from a region of

their higher concentration to a their higher concentration to a region of their lower concentration, through a region of their lower concentration, through a

partially permeable membranepartially permeable membrane Water will move by osmosis into and out of cells due Water will move by osmosis into and out of cells due

to differences in water potential between the cell and to differences in water potential between the cell and its surroundings. its surroundings.

Water potential is the chemical potential of water and Water potential is the chemical potential of water and is a measure of the energy available for reaction or is a measure of the energy available for reaction or movement (Bidwell 1974:59). movement (Bidwell 1974:59).

. .

Some Basic Principles of OsmosisSome Basic Principles of Osmosis

Water always moves from high water potential to low Water always moves from high water potential to low water potential. water potential.

Water potential is a measure of the tendency of water Water potential is a measure of the tendency of water to move from high free energy to lower free energy. to move from high free energy to lower free energy.

Distilled water in an open beaker has a water Distilled water in an open beaker has a water potential of 0(zero). potential of 0(zero).

The addition of solute decreases water potential. The addition of solute decreases water potential. The addition of pressure increases water potential. The addition of pressure increases water potential. In cells, water moves by osmosis to areas where In cells, water moves by osmosis to areas where

water potential is lower. water potential is lower. A hypertonic solution has lower water potential. A hypertonic solution has lower water potential.

A hypotonic solution has higher water potentialA hypotonic solution has higher water potential

OSMOSISOSMOSIS

DIAGRAMDIAGRAMHypertonic SolutionsHypertonic Solutions: contain a : contain a high concentration high concentration of soluteof solute relative to another solution (e.g. the cell's relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypertonic cytoplasm). When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing solution, the water diffuses out of the cell, causing the cell to shrivel. the cell to shrivel.

Hypotonic SolutionsHypotonic Solutions: contain a : contain a low concentration of low concentration of solutesolute relative to another solution (e.g. the cell's relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypotonic cytoplasm). When a cell is placed in a hypotonic solution, the water diffuses into the cell, causing the solution, the water diffuses into the cell, causing the cell to swell and possibly explodecell to swell and possibly explode

Isotonic SolutionsIsotonic Solutions: contain the : contain the same concentrationsame concentration of of solute as an another solution (e.g. the cell's solute as an another solution (e.g. the cell's cytoplasm). When a cell is placed in an isotonic cytoplasm). When a cell is placed in an isotonic solution, the water diffuses into and out of the cell at solution, the water diffuses into and out of the cell at the same rate. The fluid that surrounds the body cells the same rate. The fluid that surrounds the body cells is isotonic. is isotonic.

Summary of the direction of OSMOSISSummary of the direction of OSMOSISCONDITIONCONDITION CELL CELL

SOLO’ NSOLO’ NENV’T ENV’T SOLU’NSOLU’N

WATERWATER

MOV’TMOV’T

CELLCELL

RXN.RXN.

1. solute 1. solute concentration in concentration in the surrounding the surrounding solution is higher solution is higher then in the cell, then in the cell, solvent is lower solvent is lower

HypotonicHypotonicHypertonicHypertonic

Away Away from the from the cellcell

shrinkshrink

2. solute 2. solute concentration in concentration in the surrounding the surrounding solution is lower solution is lower then in the cell, then in the cell, solvent is higher solvent is higher

HypertoniHypertonicc

HypotonicHypotonic Towards Towards the cellthe cell

swellswell

3. Solute 3. Solute concentration is concentration is equal between the equal between the surrounding surrounding solution and that of solution and that of the cell the cell

IsotonicIsotonic IsotonicIsotonic In and In and out of out of the cellthe cell

No No changechange

ACTIVE TRANSPORTACTIVE TRANSPORTEndocytosis begins when a particle contacts the plasma Endocytosis begins when a particle contacts the plasma membrane of a cell. An invagination of the membrane membrane of a cell. An invagination of the membrane occurs until the particle is completely wrapped in occurs until the particle is completely wrapped in membrane. The wrapped particle is now inside a vesicle membrane. The wrapped particle is now inside a vesicle in the interior of the cell. There are two types of in the interior of the cell. There are two types of endocytosis: phagocytosis and pinocytosis. endocytosis: phagocytosis and pinocytosis.

Exocytosis is the reverse of endocytosis. In this case Exocytosis is the reverse of endocytosis. In this case material exits from the cell. As with endocytosis, the material exits from the cell. As with endocytosis, the plasma membrane is actively involved. Material in a sac plasma membrane is actively involved. Material in a sac or vesicle moves to the membrane and when it makes or vesicle moves to the membrane and when it makes contact the membrane opens and the material inside the contact the membrane opens and the material inside the vesicle pours out. Note that the plasma membrane and the vesicle pours out. Note that the plasma membrane and the vesicle membrane fuse to form a new border for the cell. vesicle membrane fuse to form a new border for the cell.

The difference between the two has to do with the size of the The difference between the two has to do with the size of the material ingested. material ingested.

1. 1. PhagocytosisPhagocytosis ((cell eatingcell eating) is shown above and occurs when ) is shown above and occurs when solid material is involved. A white blood cell phagocytosis solid material is involved. A white blood cell phagocytosis bacteria when it ingests them and breaks them down inside the bacteria when it ingests them and breaks them down inside the cell. cell.

2. 2. PinocytosisPinocytosis ( (cell drinkingcell drinking) occurs when smaller particles, such ) occurs when smaller particles, such as large molecules, that are in solution are ingested by a cell. as large molecules, that are in solution are ingested by a cell. The process is the same as that shown above, but the type of The process is the same as that shown above, but the type of material taken into the cell differs material taken into the cell differs

CELLULAR METABOLISMCELLULAR METABOLISM

a a major biochemical pathway along major biochemical pathway along which the cells release the chemical bond which the cells release the chemical bond energy from the food and convert it to energy from the food and convert it to usable form (ATP)usable form (ATP)

the many synthesis or breakdown of the many synthesis or breakdown of material taking place within the cell.material taking place within the cell.

METABOLISM AND ENERGY:METABOLISM AND ENERGY:

1. ENDERGONIC REACTION 1. ENDERGONIC REACTION – the synthesis – the synthesis of compounds which require energy outside of compounds which require energy outside the reacting substancesthe reacting substances

Ex. PhotosysntesisEx. Photosysntesis2. EXERGONIC REACTION 2. EXERGONIC REACTION – the life – the life

processes accompanied by loss or release of processes accompanied by loss or release of energyenergy

Ex. Maintenace and repair, secretion of Ex. Maintenace and repair, secretion of substances, physiological oxidationssubstances, physiological oxidations

CELLULAR RESPIRATIONCELLULAR RESPIRATION

the series of complex oxidation reactions the series of complex oxidation reactions whereby living whereby living

cells obtain energy through breakdown of cells obtain energy through breakdown of organic substances and other intermediate organic substances and other intermediate materialsmaterials..

release of energy by the oxidation of fuel release of energy by the oxidation of fuel molecules by taking oxygen and release molecules by taking oxygen and release carbon dioxidecarbon dioxide

TYPES OF CELLULAR TYPES OF CELLULAR RESPIRATION:RESPIRATION:

1.ANAEROBIC RESPIRATION /GLYCOLYSIS1.ANAEROBIC RESPIRATION /GLYCOLYSIS - the cytoplasmic cellular activity which consists of the - the cytoplasmic cellular activity which consists of the

enzymatic breakdown of glucose molecules without the use of enzymatic breakdown of glucose molecules without the use of molecular oxygenmolecular oxygen

glucose is stable molecule and will not decompose glucose is stable molecule and will not decompose spontaneously to release energy:spontaneously to release energy:

1 glucose molecule - 2 ATP molecules1 glucose molecule - 2 ATP molecules involves involves phosphorylation reactionphosphorylation reaction – phosphates are released – phosphates are released

from the 2 ATP and become ADP and the other phosphate from the 2 ATP and become ADP and the other phosphate become attached to glucose and form become attached to glucose and form PHOSPHORYLATED PHOSPHORYLATED SUGARSUGAR (P-C6-p) under the control of the enzyme (P-C6-p) under the control of the enzyme phosphorylase.phosphorylase.

Products: 2 ATP, 2 pyruvic acids (3-carbon sugar),lactic Products: 2 ATP, 2 pyruvic acids (3-carbon sugar),lactic acidsacids

2. AEROBIC RESPIRATION / KREB’S 2. AEROBIC RESPIRATION / KREB’S CYCLE/CITRIC ACID CYCLE CYCLE/CITRIC ACID CYCLE

a series of oxidation-reduction mitochondrial reactions that a series of oxidation-reduction mitochondrial reactions that complete the breakdown of pyruvic acid produced by complete the breakdown of pyruvic acid produced by glycolysisglycolysis

pypyruvic acid must enter the mitochondrion so that it can be pypyruvic acid must enter the mitochondrion so that it can be used as a source of energyused as a source of energy

3-carbon pyruvic acid molecules is reacted upon by acetyl-co-3-carbon pyruvic acid molecules is reacted upon by acetyl-co-enzyme a, and carbon dioxide is the waste product and is enzyme a, and carbon dioxide is the waste product and is eventually released into the atmosphereeventually released into the atmosphere

5 pairs of hydrogen bonds are removed and become attached 5 pairs of hydrogen bonds are removed and become attached to the H carriersto the H carriers

involves 3 uses of water and ETSinvolves 3 uses of water and ETS products: 34 ATP(17 per pyruvic acid), Carbon Dioxide, products: 34 ATP(17 per pyruvic acid), Carbon Dioxide,

waterwater

COMPARISON OF ANAEROBIC AND AEROBIC COMPARISON OF ANAEROBIC AND AEROBIC RESPIRATIONRESPIRATION

BASISBASIS GLYCOLYSISGLYCOLYSIS KREB’S CYCLEKREB’S CYCLE

1. Site1. Site

2. Oxygen 2. Oxygen requirementrequirement

3. Raw 3. Raw materials/Energy materials/Energy

SourceSource

4. Processes 4. Processes involvedinvolved

CytoplasmCytoplasm

Do not require oxygenDo not require oxygen

1 Glucose molecule 1 Glucose molecule (CHO,CHON, Fats)(CHO,CHON, Fats)

Breakdown of glucose to Breakdown of glucose to pyruvic acid, pyruvic acid, phosphorylation, lactic phosphorylation, lactic acid formationacid formation

MitochondrionMitochondrion

Require oxygenRequire oxygen

2 Pyruvic acid from 2 Pyruvic acid from glycolysisglycolysis

Breakdown of pyruvic Breakdown of pyruvic acidsacids

BASISBASIS GLYCOLYSISGLYCOLYSIS KREB’SKREB’S

5. Enzymes5. Enzymes

6. Products 6. Products

Phosphorylase, Phosphorylase, NAD(Nicotinamide NAD(Nicotinamide Adenine Dinucleotide,Adenine Dinucleotide,

2 ATP, 2 pyruvic acids 2 ATP, 2 pyruvic acids (3-carbon sugar),lactic (3-carbon sugar),lactic acidsacids

CHO (FATS,CHON)CHO (FATS,CHON)

GLYCOGENGLYCOGEN

GLUCOSEGLUCOSE

PYRUVIC ACID , ATP,PYRUVIC ACID , ATP,

LACTIC ACIDSLACTIC ACIDS

Coenzyme A (CoA), Coenzyme A (CoA), FAD (Flavin Adenine FAD (Flavin Adenine Dinucleotide)Dinucleotide)

34 ATP(17 per pyruvic 34 ATP(17 per pyruvic acid), Carbon Dioxide, acid), Carbon Dioxide, waterwater

PYRUVIC ACIDPYRUVIC ACID

OXALOACETIC OXALOACETIC ACID(CoA)ACID(CoA)

ATP, COATP, CO2 2 , H, H