PHOTOSYNTHESIS & CELLULAR RESPIRATION

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ENERGY IN A CELL!!

• Your body requires energy in order to function…from your heart beating to intense workouts.

• Energy is essential to LIFE!!

• Your body stores energy in a molecule called ATP’s (adenosine triphosphate)

• This is a quick source of energy for any organelle in the cell that needs it.

• The energy inside an ATP molecule is released when it loses a phosphate and becomes ADP (adenosine diphosphate)

• ADP is like a partially charged battery while ATP is a fully charged battery.

“Chlorophyll, more like borophyll!”

• Sorry, just had to make an effort to take away the chance for the smart elacks that will be lucky to make a C in this class to use this line and get a laugh. Now they can pay attention for the 5 minutes their little pea-size brain will allow them…

PHOTOSYNTHESIS

• Photosynthesis is a process in which solar energy in the form of light is converted into chemical energy within carbohydrate molecules.

EQUATION FOR PHOTOSYNTHESIS

• 6 CO2 + 6 H2O + light ---> C6H12O6 + 6 O2

PHOTOSYNTHESIS

•Photosynthesis occurs in organelles, present in green plants and certain algae, called Chloroplasts.

Chloroplast

CHLORPLAST

• A chloroplast is filled with stacks of membrane sacs called thylakoids.

• Thylakoids are stacked in columns of grana.

Chloroplast

• A chloroplast usually has dozens of granum.

• They are suspended

in a fluid matrix called the stroma.

• Chlorophyll molecules are embedded in the thylakoid membranes.

Chloroplast

This is a close up version of a chloroplast in a leaf.

•These chloroplasts contain the green pigment called chlorophyll.

Chloroplast

CHLOROPHYLL

• Chlorophyll- pigment found in plants it will absorb red, blue, and violet better than other colors.

• Green light is primarily reflected so most leaves appear green to us.

• There are two types of chlorophyll a and b

CHLOROPHYLL

• Notice how Chlorophyll a absorbs light mostly in the blue-violet and red regions.

• Chlorphyll b absorbs light in the blue and red regions more.

CHLOROPHYLL

• Because light is a form of energy, any compound that absorbs light also absorbs the energy in that light.

• When chlorophyll absorbs light much of the energy is transferred directly to electrons in the chlorophyll molecule, raising the energy available in these electrons.

CHLOROPHYLL

• Electrons carriers are seen throughout the Photosynthesis concept.

• They are compounds that can accept high-energy electrons and transfer them along with most of their energy to another molecule. – NADP+ NADPH– ADP ATP

2 REACTIONS OF PHOTOSYNTHESIS

• Photosynthesis involves 2 reactions:1. Light Reaction.2. Calvin Cycle.

(Also called Light Independent Reaction and Dark Reaction.)

STOMATA

• The stomata are important for the exchange of gases by diffusion between the outside air and intercellular spaces for respiration and also for the evaporation of water by transpiration.

• Notice how the equation for photosynthesis relates to the reactions shown in the diagram below.6CO2 + 6H2O + Energy C6H12O6 + 6O2

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Melvin Calvin (1911 –1997)

• Again, this is also known as the Calvin Cycle

• Named after the American scientist Melvin Calvin, who worked out the details of this cycle in 1948

• Won Nobel Prize in chemistry in 1961

http://www.brainpop.com/science/plantsandanimals/photosynthesis/index.weml?&tried_cookie=true

CELLULAR RESPIRATION

C6H12O6 + 6O2 ---> 6 CO2 + 6 H2O + Energy

CELLULAR RESPIRATION

•The process by which living organisms obtain energy from the bonds of food.

•There are two important ways the cells can harvest energy from food….cellular respiration and fermentation

AEROBIC RESP.

• Aerobic respiration occurs when oxygen is present.

• Aerobic respiration produces a relatively large amount of energy (ATP)

ANAEROBIC RESP.

• Anaerobic respiration occurs when oxygen is not present.

• Produces few ATP’s

• Anaerobic respiration may also be called fermentation.

WHAT IS ATP?

• (adenosine triphosphate) compound that contains 3 high energy phosphate bonds and is an important source of energy for cells

ATP

CELLULAR RESPIRATION

• Cellular Respiration consists of 3 major stages:

• Glycolysis

• Krebs Cycle

• Electron Transport Chain..(ETC)

GLYCOLYSIS

• They (CR and Fermentation) both start with the Glycolysis

• The 1st stage of cellular respiration. • Occurs in the cytoplasm of the cell.• Occurs in both aerobic and

anaerobic conditions.• BUT Does NOT require oxygen

GLYCOLSIS

•This metabolic pathway breaks down glucose (produced in photosynthesis) to 2 molecules of pyruvate

•There is a net gain of 2 ATP molecules.

KREBS CYCLE

• Also known as citric acid cycle

• 2nd phase of aerobic respiration

• Occurs in the Mitochondria

Kreb Cycle

• The process of Kreb Cycle is essentially removing carbon dioxide, getting out energy in the form of ATP, NADH and FADH2, and lastly regenerating

the cycle.

Kreb Cycle• The Kreb Cycle has a by-product of

CO2

• Energy is carried to the ETC by two electron carriers….NADH and FADH2

• A total of two ATP’s are produces through the Kreb Cycle

Hans Krebs (1900 – 1981)

• Krebs cycle named after Hans Krebs, biochemist who demonstrated its existence

• Born in Germany, son of Jewish physician, forced to leave Nazi Germany in 1933

• Spent rest of life in Great Britain

• Discoveries were initially rejected

• Won Nobel Prize in 1953 in medicine & physiology

ELECTRON TRANSPORT CHAIN (ETC)

• Last stage of cellular respiration

• Series of Reactions in which an electron is passed from one molecule to another to produce energy for synthesis of ATP

ETC

• The electrons move down the chain along the inner membrane of the mitochondria

• They are carried by NADH and FADH2 (carrier molecules)

ETC• As hydrogen ions move across the

channels in the membrane to the matrix, they release energy that is used by an enzyme to make ATP

• Oxygen is the final electron acceptor.• Water is formed in this process..it is

a by-product

ETC

• Results in ETC the electron transport chain produces 32 molecules of ATP

• With H2O being a by-product

• O2 enters the ETC

Cellular Respiration

• TOTAL ATP PRODUCTION IN CELLULAR RESPIRATION

o Glycolysis, 2 ATPs

o Krebs, 2 ATPs +

o ETC, 32 ATPs

o = 36 ATPs TOTAL

OVERVIEW

• Glycolysis is anaerobic• When oxygen is present, then the

previously discussed pathway (Krebs cycle, ETC) is taken

• When oxygen is NOT present, a different pathway is taken, fermentation

CELLULAR RESPIRATION

• A car and our bodies are similar in the fact that the mitochondria is our bodies engine that burns sugar for fuel. The exhaust would be H2O and CO2

FERMENTATION

• Fermentation releases energy from food molecules in the absence of oxygen.

The Process of Fermentation

• Glucose is broken down into pyruvate during glycolysis

• Pyruvate is then broken down into ethyl alcohol or lactic acid

• Only results in 2 ATP molecules (vs. 36 from aerobic)

ALCOHOLIC FERMENTATION

• Most common type of fermentation is yeast cells converting pyruvate into ethyl alcohol

• Fermentation by itself is able to produce liquids that are about 15% alcohol

• The same process enables yeast cells to convert the sugar in dough to ethyl alcohol & carbon dioxide

FERMENTATION

• Bakers use alcoholic fermentation of yeast to make breads

• As yeast ferments, it causes dough to rise & create the bubbles that are present in bread

FERMENTATION

• As the dough bakes, yeast cells die and the alcohol they have made evaporates

FERMENTATION

• Also used to make wine, beer, and ethanol added to gasoline

                            

LACTIC ACID FERMENTATION

• Occurs in muscle cells when they use up all the available oxygen

• Muscle cells feel fatigued and sore b/c lactic acid forms when oxygen is NOT present

LACTIC ACID

• Most lactic acid made in muscles diffuses into bloodstream, then to liver, where it is converted back to pyruvate, which enters the aerobic respiration process

• Yogurt, cheeses, rye bread, pickles, sauerkraut, and olives are lactic acid products

LACTIC ACID

• Yogurt, cheeses, rye bread, pickles, sauerkraut, and olives are lactic acid products