key concept all cells need chemical energy. cell energy = atp atp = adenosine triphosphate

4.1 Chemical Energy and ATP

KEY CONCEPT All cells need chemical energy.Cell Energy = ATPATP = Adenosine Triphosphate


• ATP transfers energy from the breakdown of food molecules to cell functions.

– Energy is released when a phosphate group is removed.– ADP – adenosine diphosphate– ADP is changed into ATP when a phosphate group is

added.triphosphateadenosine

adenosine diphosphate

tri=3

di=2


Molecules in food store chemical energy in their bonds.

Starch molecule

Glucose molecule


• Fats store the most energy.

– 80 percent of the energy in your body– about 146 ATP from a triglyceride

• Proteins are least likely to be broken down to make ATP.


Autotroph - manufacture own food

• most use photosynthesis– converts sunlight into chemical E– chemical E is stored in the form of sugars

Heterotrophs – rely on other sources for E


A few autotrophs do not need sunlight and photosynthesis as a source of energy.

• live in places that never get sunlight.

• Chemosynthesis– uses chemical E (S)

instead of light E to make food

– Chemosynthetic bacteria – hydrothermal vents


Photosynthetic organisms are autotrophs =producers

• Photosynthesis captures E from sunlight to make food – sugar

• Glucose• All sugars end in -ose• 2 phases of photosynthesis

1. light-dependent reactions

2. light-independent reactions

4.2 Overview of Photosynthesis


Light and Pigments

1. visible spectrum – wavelengths the human eye can see

2. different colors have different wavelengths

3. Pigment - absorb specific wavelengths of light


crest

Trough

I------------------I wavelength


Photosynthesis takes place in chloroplast

Chloroplast contains pigments to capture light• Chlorophyll reflects green light & absorb all others• Carotenoids – reflect orange light & …• Anthocyanine – reflect purples and red light & …



The light-dependent reactions– Takes place in the grana (thylakoids)– water and sunlight are needed– chlorophyll absorbs E from sunlight

– water molecules are split – PhotolysisPhotolysis – H2O – H2O H + O H + O– E and hydrogen ions are passed on to the light-

independent reactions– oxygen is released as waste



The light-independent reactions

– Takes place in the Stroma – space between– needs carbon dioxide from atmosphere– Calvin cycle - Carbon fixationCarbon fixation

– use E from light dependent reaction to build a 6 carbon chain of sugar (glucose)

– C6H12O6



• Sugar is then transported to the roots, stems, and fruits of the plants

• sugar can be used, or stored as starch, and some is built into cellulose

• We obtain E from plants by eating the stored sugar



• The equation for the overall process is:

6CO2 + 6H2O C6H12O6 + 6O2

C6H12O6

granum (stack of thylakoids)

thylakoid

sunlight

1 six-carbon sugar

6H2O

6CO2

6O2

chloroplastchloroplast1

2

43

energy

stroma (fluid outside the thylakoids)



Light Dependent Light Independent


Glycolysis - splits glucose into two molecules of pyruvate (pyruvic acid)

– C-C-C-C-C-C C-C-C + C-C-C– Produces some ATP molecules– Takes place in cytoplasm

4.5 Cellular Respiration in Detail


Aerobic

Anaerobic Respiration


Aerobic Respiration

Two steps

1. Krebs Cycle


Aerobic Respiration

1. The Krebs cycle – takes place in

mitochondrial matrix– breaks down pyruvic acid– makes a small amount of

ATP– releases carbon dioxide

6H O2

6CO 2

6O 2

mitochondrionmitochondrion

matrix (area enclosedby inner membrane)

inner membrane

ATP

ATP

energy

energy from glycolysis

1

2

4

3

and

and

and

Krebs Cycle

4.4 Overview of Cell Respiration


Aerobic Respiration2. The Electron Transport Chain

takes place on the cristaeMakes a large amount of ATPWater is released as a waste product

4.5 Cellular Respiration in Detail


• The equation for the overall process is:

C6H12O6 + 6O2 6CO2 + 6H2O

• The reactants in photosynthesis are the same as the products of cellular respiration.

4.4 Overview of Cell Respiration


KEY CONCEPT Fermentation allows the production of a small amount of ATP without oxygen - Anaerobic

4.6 Fermentation


• Lactic acid fermentation occurs in muscle cells.

1. glycolysis two pyruvate molecules

2. converts pyruvate into lactic acid– Muscle pain and weakness

4.6 Fermentation


Fermentation and its products are important in several ways.

• Fermentation is used in food production.– Alcoholic fermentation

- energy is used to split pyruvate into ethyl alcohol and carbon dioxide

- Yogurt, cheese, bread

4.6 Fermentation


• Fermentation is used in food production.

– yogurt

– cheese

– bread

4.6 Fermentation


CO2


Extra Credit

• Create an alphabet picture book for middle school kids with ideas relating to cell biology

• Due: Monday Oct 22nd

key concept all cells need chemical energy. cell energy = atp atp = adenosine triphosphate

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