Living Organisms & Energy Moretz, biology 2017

Lecture Outline Importance of energy in living organisms Photosynthesis Process of photosynthesis Purpose of photosynthesis Respiration Purpose of respiration Process of respiration Fermentation

Importance of Energy Living organisms need energy to do everything. Move Grow Reproduce Photosynthesis & respiration are needed for living organisms to get energy.

Photosynthesis vs. Respiration Photosynthesis- turns energy into sugars Respiration- turns sugars into energy Photosynthesis Energy Sugars Respiration

How do plants meet their energy needs? Remember, science is a process….. …..a brief history lesson is in order

The process of understanding photosynthesis Until almost 350 years ago, plants were thought to feed on soil Jan Baptista van Helmont Planted willow tree in pot Allowed tree to grow for 5 years Compared weight of tree and soil to original weight Tree gained 74kg, soil lost 57g

The process of understanding photosynthesis 100 yrs later we learned that plants release oxygen into the atmosphere Joseph Priestly Candles “damaged” air Sprigs of mint “restored” air

The process of understanding photosynthesis Finally, ~1800 Jan Ingenhousz determined: Air was “restored” only in the presence of sunlight Only by a plant’s green leaves, not by it roots But, he suggested that the source of the oxygen was CO2

What is photosynthesis? photo = light synthesis = to put together

Process of photosynthesis Process by which a cell captures energy and uses it to make food. Photosynthesis is a 2 step process: Capture energy Turn energy into food

Step 1: Capturing Energy Plants capture the light energy from the sun. Chlorophyll absorbs the light energy. Pigment that is good at absorbing a certain wavelength of light. Located in the chloroplast. Organelle located ONLY in plant cells. The light energy captured by the chlorophyll is needed to turn energy into food.

Capturing Energy

Capturing Energy

Capturing Energy Chlorophyll

Step 2: Turning energy into food Plant cells use the captured light energy to produce “food.” Water (H2 O) and carbon dioxide (CO2 ) are needed to make the food. Roots absorb water from the soil. Carbon dioxide enters the plant through stomata. Light energy changes the water & carbon dioxide into glucose and oxygen (O2).

Stomata Small openings on the underside of leaves. Gases enter and exit through these openings.

Stomata Small openings on the underside of leaves. Gases enter and exit through these openings.

Glucose “Food” produced during photosynthesis. Glucose = C6H12O6 “Food” produced during photosynthesis. Simple carbohydrate (sugar)

Process of photosynthesis 6 CO2 + 6H2 O C6H12O6 + 6O2 6 carbon dioxide molecules and 6 water molecules produces 1 glucose molecule and 6 oxygen molecules. light

Photosynthetic Organisms Carried out by a variety of organisms simple bacteria, to algae and complex plants. Photosynthetic organisms = “producer” or “autotroph.”

Pd 2

Importance of Photosynthesis Releases oxygen into the atmosphere. Dead plant matter is a source of fossil fuels. Most living things obtain energy either directly or indirectly from the sun’s energy captured during photosynthesis. Pd 1

Importance of Photosynthesis Without photosynthesis, living organisms would not get energy!!! Energy enters the ecosystem through photosynthesis. Plants use the sun’s energy to make glucose. All other organisms consume glucose from the producers as a source of energy.

Flow of Energy

Flow of Energy

Before respiration… All organisms get energy from the food they eat / make.

Before respiration… Food passes through the digestive system and is broken into smaller pieces.

Before respiration… Smaller food molecules pass from the digestive system to the blood stream. Small sugar molecules (GLUCOSE) then go to the cells where respiration occurs.

Respiration What? Who? Where? Process of getting energy. Cells break down sugar (glucose) and release the energy. Who? ALL living organisms Where? Occurs in the cytoplasm and mitochondria of all cells, in BOTH plant and animal cells.

The Process of Respiration Glycolysis (fermentation) Glucose is broken into smaller molecules (pyruvate). Occurs in the cytoplasm. Anaerobic - Oxygen is NOT needed. Four molecules of energy (ATP) is produced. Two molecules are used in the process. Net production = 2 molecules of ATP

The Process of Respiration Glycolysis Glucose is broken into smaller molecules (pyruvate). Two molecules of energy (ATP) is released.

The Process of Respiration Glycolysis Glucose is broken into smaller molecules (pyruvate). Two molecules of energy (ATP) is released.

The Process of Respiration The Kreb’s Cycle Pyruvate goes into the mitochondria. Pyruvate molecules is broken into even smaller molecules. Pyruvate turns into Acetyl-CoA

The Process of Respiration The Kreb’s Cycle Pyruvate goes into the matrix of the mitochondria.

The Process of Respiration The Kreb’s Cycle Pyruvate goes into the matrix of the mitochondria. Pyruvate molecules is broken into even smaller molecules. Pyruvate turns into Acetyl-CoA Acetyl-CoA is turned into ATP CO2 is produced. Electron carrying molecules are produced (FADH and NADH) Aerobic - Oxygen is required. 1molecules of energy (ATP) is produced.

The Process of Respiration The Kreb’s Cycle Pyruvate goes into the mitochondria. Pyruvate molecules is broken into even smaller molecules. Pyruvate turns into Acetyl-CoA Acetyl-CoA is turned into ATP FADH and NADH are produced. CO2 is produced. 2 molecules of energy (ATP) is produced.

The Process of Respiration 3. Electron Transport Chain Electrons are passed from one molecule to another. Given from the NADH and FADH molecules In the membrane of the mitochondria Energy produced from electron transfer is stored in ATP If Oxygen is not present, ETC stops and ATP isn’t produced.

The Process of Respiration Energy produced from electron transfer is stored in ATP If Oxygen is not present, ETC stops and ATP isn’t produced.

The Process of Respiration 3. Electron Transport Chain Electrons are passed from one molecule to another. Given from the NADH and FADH molecules In the membrane of the mitochondria Produces ATP Oxygen is the last electron acceptor. Joins with H+ and produces water. Aerobic - Oxygen is required. 32 molecules of energy (ATP) is produced. Energy produced from electron transfer is stored in ATP If Oxygen is not present, ETC stops and ATP isn’t produced.

The Process of Respiration

The Process of Respiration Glucose In the cytoplasm Small molecules In the mitochondria Energy

The Process of Respiration Water Oxygen Carbon dioxide Smaller molecules LOTS of Energy

Process of respiration C6H12O6 + 6O2 6CO2 + 6H2 O + ATP One molecule of glucose and six molecules of oxygen make six molecules of carbon dioxide, six water molecules, and 36 molecules of ATP.

ATP = Energy Universal energy storage molecule. All organisms break down ATP to get energy. Energy is released when the chemical bonds in ATP are broken.

Fermentation What happens if oxygen is not available? The cell can use Fermentation instead!! Occurs in the Cytoplasm Just like glycolysis!! Anaerobic respiration process

Pyruvic Acid + NADH  alcohol + CO2 + NAD+ 2 Types of Fermentation Alcoholic Fermentation Yeasts use this process to form ethyl alcohol and carbon dioxide as waste products. This causes bread dough to rise This is how some alcoholic beverages are made Pyruvic Acid + NADH  alcohol + CO2 + NAD+

Anaerobic respiration Alcoholic fermentation

Lactic Acid Fermentation Occurs in bacteria (unicellular organisms) This is how cheese, yogurt, and pickles are made. Occurs in muscles during rapid exercise When your body runs out of oxygen your muscle cells must produce some ATP using fermentation and glycolysis Lactic Acid build-up causes muscle soreness or burning after intense activity. Pyruvic Acid + NADH  lactic acid + NAD+

Anaerobic respiration Lactic acid fermentation

Fermentation Summary Fermentation: 2 Pyruvic Acid  ? or ? Glycolysis: Glucose  2 Pyruvic Acid

Photosynthesis & respiration summary Glucose is made during photosynthesis. Glucose is broken down and energy is released during respiration. All organisms use energy released to do everything. Photosynthesis Energy Sugars Respiration