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CELL PHYSIOLOGY CELL PHYSIOLOGY and and CELLULAR METABOLISM CELLULAR METABOLISM

Cell Physiology

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CELL PHYSIOLOGY and CELLULAR METABOLISM

CELL PHYSIOLOGY

The the processes or functions of the cellCELL TRANSPORT 2 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 TRANSPORT- Does not require energy - Does not require oxygen -flow of materials is from greater to lesser concentration(follows concentration gradient)

ACTIVE TRANSPORT

- requires for energy - requires oxygen - flow of materials is from lesser to greater concentration (does not follow concentration gradient) - flow rate is faster - examples: - flow rate is slower Endocytosis - examples: Diffusion, Diffusion,Selectively permeable Phagocytosis membranes ,Osmosis (isotonic, Pinocystosis hypotonic and hypertonic Exocytosis solutions) Facilitated diffusion

SOLUTION, SOLVENT AND SOLUTE

A solution is a homogenous molecular mixture of two or more substances. The substance that has the greatest concentration is the solvent. It is the substance that dissolves the other substance(s) in the solution. Substances that are found in lesser concentration in solutions are solutes. Solutes are the substances dissolved by solvents. solutes. When you put a spoonful of sugar in a cup of water, the result is a solution. The water is the solvent and the sugar is the solute. Suppose you have a cup of coffee with sugar in it. __________ is the solvent and _________ and __________ are the solutes.

DIFFUSION

The principle means of passive transport Diffusion - The random movement of molecules from a area of higher concentration to an area of lower concentration. the direction of diffusion is determined by the concentration of specific molecules in the two sides of the membrane and the energy that causes the diffusion

DIFFUSION

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 DIFFUSIONSOLID OVER a. solid - MASTICATION b. liquid - DIGESTION c. gas - TRANSPIRATION 2. LIQUID OVER a. solid - PERSPIRATION b. liquid -DIGESTION c. gas - EVAPORATION 3. GAS OVER a. solid - SUBLIMATION b. liquid - OXYGENATION c. gas - RESPIRATION1.

DIFFUSION OF SOLID OVER LIQUID

What factors can influence the rate of diffusion?

Temperature. The state of the solvent; i.e. whether the solvent is a solid, liquid or gas. The size of the molecules. The steepness of the diffusion gradient. Permeability Size of molecules Size of pores Solubility Electrical charges Membrane structure

Property of Diffusion

The greater the space between these molecules the greater the ability for the molecular particles to spread out from one another. The more packed the molecules are in the substance the less space to maneuver, and therefore, the more difficult for diffusion to occur. Requires diffusion pressure

OSMOSIS

is the movement of water molecules from a region of their higher concentration to a region of their lower concentration, through a partially permeable membrane Water will move by osmosis into and out of cells due to differences in water potential between the cell and its surroundings. Water potential is the chemical potential of water and is a measure of the energy available for reaction or movement (Bidwell 1974:59).

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Some Basic Principles of Osmosis

Water always moves from high water potential to low water potential. Water potential is a measure of the tendency of water to move from high free energy to lower free energy. Distilled water in an open beaker has a water potential of 0(zero). The addition of solute decreases water potential. The addition of pressure increases water potential. In cells, water moves by osmosis to areas where water potential is lower.

A hypertonic solution has lower water potential.

A hypotonic solution has higher water potential

OSMOSIS

DIAGRAMHypertonic Solutions: contain a high concentration Solutions: of solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing the cell to shrivel. Hypotonic Solutions: contain a low concentration of Solutions: solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypotonic solution, the water diffuses into the cell, causing the cell to swell and possibly explode Isotonic Solutions: contain the same concentration of Solutions: solute as an another solution (e.g. the cell's cytoplasm). When a cell is placed in an isotonic solution, the water diffuses into and out of the cell at the same rate. The fluid that surrounds the body cells is isotonic.

Summary of the direction of OSMOSISCONDITION1. solute concentration in the surrounding solution is higher then in the cell, solvent is lower 2. solute concentration in the surrounding solution is lower then in the cell, solvent is higher 3. Solute concentration is equal between the surrounding solution and that of the cell

CELL SOLO N

ENVT SOLUN

WATER MOVT

CELL RXN.

Away shrink Hypertonic from the Hypotonic cellHypertoni Hypotonic c

Towards swell the cell

Isotonic

Isotonic

In and out of the cell

No change

ACTIVE TRANSPORTEndocytosis begins when a particle contacts the plasma membrane of a cell. An invagination of the membrane occurs until the particle is completely wrapped in membrane. The wrapped particle is now inside a vesicle in the interior of the cell. There are two types of endocytosis: phagocytosis and pinocytosis. Exocytosis is the reverse of endocytosis. In this case material exits from the cell. As with endocytosis, the plasma membrane is actively involved. Material in a sac or vesicle moves to the membrane and when it makes contact the membrane opens and the material inside the vesicle pours out. Note that the plasma membrane and the vesicle membrane fuse to form a new border for the cell.

The difference between the two has to do with the size of the material ingested. 1. Phagocytosis (cell eating) is shown above and occurs when eating) solid material is involved. A white blood cell phagocytosis bacteria when it ingests them and breaks them down inside the cell.

2. Pinocytosis (cell drinking) occurs when smaller particles, such drinking) 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 material taken into the cell differs

CELLULAR METABOLISM

a major biochemical pathway along

which the cells release the chemical bond energy from the food and convert it to usable form (ATP)

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

METABOLISM AND ENERGY:1. ENDERGONIC REACTION the synthesis of compounds which require energy outside the reacting substances Ex. Photosysntesis 2. EXERGONIC REACTION the life processes accompanied by loss or release of energy Ex. Maintenace and repair, secretion of substances, physiological oxidations

CELLULAR RESPIRATION

the series of complex oxidation reactions whereby living cells obtain energy through breakdown of organic substances and other intermediate materials. materials. release of energy by the oxidation of fuel molecules by taking oxygen and release carbon dioxide

TYPES OF CELLULAR RESPIRATION:1.ANAEROBIC RESPIRATION /GLYCOLYSIS - the cytoplasmic cellular activity which consists of the enzymatic breakdown of glucose molecules without the use of molecular oxygen glucose is stable molecule and will not decompose spontaneously to release energy: 1 glucose molecule - 2 ATP molecules involves phosphorylation reaction phosphates are released from the 2 ATP and become ADP and the other phosphate become attached to glucose and form PHOSPHORYLATED SUGAR (P-C6-p) under the control of the enzyme (P-C6phosphorylase. Products: 2 ATP, 2 pyruvic acids (3-carbon sugar),lactic (3acids

2. AEROBIC RESPIRATION / KREBS CYCLE/CITRIC ACID CYCLE

a series of oxidation-reduction mitochondrial reactions that oxidationcomplete the breakdown of pyruvic acid produced by glycolysis pypyruvic acid must enter the mitochondrion so that it can be used as a source of energy 3-carbon pyruvic acid molecules is reacted upon by acetyl-coacetyl-coenzyme a, and carbon dioxide is the waste product and is eventually released into the atmosphere 5 pairs of hydrogen bonds are removed and become attached to the H carriers involves 3 uses of water and ETS products: 34 ATP(17 per pyruvic acid), Carbon Dioxide, water

COMPARISON OF ANAEROBIC AND AEROBIC RESPIRATION BASIS GLYCOLYSIS KREBS CYCLE1. Site 2. Oxygen requirement 3. Raw materials/Energy Source 4. Processes involvedCytoplasm Do not require oxygen Mitochondrion Require oxygen

1 Glucose molecule (CHO,CHON, Fats)

2 Pyruvic acid from glycolysis

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

BASIS5. Enzymes

GLYCOLYSISPhosphorylase, NAD(Nicotinamide Adenine Dinucleotide, 2 ATP, 2 pyruvic acids (3-carbon sugar),lactic (3acidsCHO (FATS,CHON) GLYCOGEN GLUCOSE PYRUVIC ACID , ATP, LACTIC ACIDS

KREBSCoenzyme A (CoA), FAD (Flavin Adenine Dinucleotide) 34 ATP(17 per pyruvic acid), Carbon Dioxide, waterPYRUVIC ACID OXALOACETIC ACID(CoA) ATP, CO2 , H

6. Products