Cell Processes

There are more than 120 elements-25 are needed for life

Water is needed for chemical reactions. About 2/3 of every cell is water

Many form the 4 basic molecules for life◦ Carbohydrates-sugar and starch used for quick energy◦ Lipids-fats, oils and waxes needed for stored energy◦ Proteins- for the growth and repair of tissues and to

fight infections◦ Nucleic Acids-DNA and RNA that have instructions for

everything-especially reproduction

1. Chemical reactions take place inside cells

a. All cells need energy. Chemical energy is stored in the bonds of molecules like glucose.

2. Cells and Energy

A process used by plants and other autotrophs to convert the energy of sunlight into sugars.

It requires sunlight, water, and carbon dioxide. It occurs in the leaves of plants in organelles

called chloroplasts.

b. Photosynthesis

EQUATION FOR PHOTOSYNTHESIS

6CO2 + 6H2O +ENERGY C6H12O6 + 6O2

CARBON DIOXIDE

WATER

GLUCOSE

OXYGEN

c. Cells Release energy in two ways1. Cellular Respiration-cytoplasm and

mitochondria converts glucose into energy, CO2 and water

2. Fermentation-allows cells to release energy without oxygen

a. Alcoholic fermentation- makes alcohol

b. Lactic Acid fermentation- makes lactic acid; milk , cheese and sore muscles

EQUATION FOR RESPIRATION

C6H12O6 +GLUCOSE

6O2

OXYGEN6CO2 +

CARBON DIOXIDE

6H2O +ENERGYWATER

ATP

*Photosynthesis and Cellular Respiration are opposite processes

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a. Certain things MUST enter the cell for it to survive. This can occur in 2 major ways:

1. PASSIVE TRANSPORT -requires no energy2. ACTIVE TRANSPORT-requires energy

3. Transport through cell membranes

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b. Important Molecules that move through cell membranes

1. Oxygen

2. Carbon dioxide

3. Water

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c. Types of Passive Transport1. Diffusion- molecules move from a higher concentration to a lower one. It does not require energy so it is passive

Cell membrane

Inside cell Outside cell

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Diffusion through a membrane

Cell membrane

Inside cell Outside cell

diffusion

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Diffusion through a membrane

Cell membrane

Inside cell Outside cell

EQUILIBRIUM

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High H2O potentialLow solute concentration

Low H2O potentialHigh solute concentration

2. Osmosis-diffusion of water across the cell membrane (also passive)

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Diffusion of Liquids

The movement from lower concentration to higher concentration

Active transport requires the use of energy 2 ways that materials are moved

1. Endocytosis -very large molecules are brought into the cell

2. Exocytosis-materials are moved out of the cell (usually wastes)

d. Types of Active Transport

Temperature Size of materials Surface area of a cell* Volume*

*The surface area can sometimes increase faster than the volume or the cell’s ability to hold materials so it stops growing

Cell Shape

4. What affects Transport of materials?

1. Cells need four large molecules to function: Carbohydrates, lipids, proteins and nucleic acids.

2. 2/3 of all cells are water3. Cells capture energy through photosynthesis

and release energy through cellular respiration and fermentation

4. Materials are moved from areas of high concentration to low concentration through passive transport that does not require energy. Diffusion and osmosis are examples.

5. In active transport, energy is required to move materials from areas of low concentration to high concentration. Endocytosis and exocytosis are examples

6. Things that affect transport are: shape, size, volume, surface area, material size and temperature

SUMMARY