Photosynthesis Respiration Cell Energy Photosynthesis and Respiration Energy

Photosynthesis & Respiration

Cell Energy (Photosynthesis and Respiration) Energy: • Energy for living things comes from food. Originally, the energy in food comes from the sun.

• Organisms that use light energy from the sun to produce food—autotrophs (auto = self) Ex: plants and some microorganisms (some bacteria and protists)

• Organisms that CANNOT use the sun’s energy to make food—heterotrophs - must eat their food Ex: animals and most microorganisms

Cell Energy: • Cells usable source of energy is called ATP • ATP stands for adenosine triphosphate Adenine Ribose 3 Phosphate groups

• ADP stands for adenosine diphosphate Adenine Ribose 2 Phosphate groups

• All energy is stored in the bonds of compounds— breaking the bond releases the energy • When the cell has energy available it can store this energy by adding a phosphate group to ADP, producing ATP

• ATP is converted into ADP by breaking the bond between the second and third phosphate groups and releasing energy for cellular processes.

Importance of ATP! 1. ALL organisms release ATP from the break down of glucose during cellular respiration 2. ATP powers the activities of the cell and allows living things to do work 3. ATP/ADP is a cycle that releases/stores energy for cell processes 4. ATP is used to actively transport material across the cell membrane

Photosynthesis • Photosynthesis is the process by which the energy of sunlight is converted into the chemical energy of glucose

• Photosynthesis occurs in the chloroplasts of plants

• Light absorbing compound is a pigment • pigments absorb some wavelengths of light and reflect others • the color our eyes see is the color that the pigment reflects

• Chlorophyll is the pigment inside the chloroplast the absorbs light for photosynthesis As the chlorophyll in leaves decays in the autumn, the green color fades and is replaced by the oranges and reds of carotenoids.

• General formula for photosynthesis carbon dioxide + water 6 CO 2 + 6 H 2 O sunlight —> : glucose + oxygen C 6 H 12 O 6 + 6 O 2

Light Reaction Takes place in the thylakoid membrane • (contains chlorophyll) Reactants needed for the light reaction: • Water, Light, ADP, NADP+ Products made from light reaction and USED in dark reaction: • ATP energy to make sugar • NADPH supplies e- and H to make C 6 H 12 O 6 Oxygen is released into the air

Dark Reaction (Calvin Cycle) Takes place in the stroma Reactants needed for the dark reaction: • CO 2, ATP, NADPH Products made from the dark reaction USED in light reaction are: • ADP returns to the light reaction to make more ATP • NADP returns to the light reaction to pick up more electrons and Hydrogens Glucose is made in the dark reaction for use throughout the organism.

Summary: Light Reaction • H 2 O is broken down and light energy is stored temporarily in ATP and NADPH. • Oxygen released. Calvin Cycle (Dark Reaction) • energy is transferred from ATP and NADPH to the organic compound glucose

Location Reactants Light Reaction Thylakoid H 2 O Light ADP and NADP from dark reaction Dark Reaction – Calvin Cycle CO 2 Stroma Products Release ATP – energy to make sugar NADPH – electrons and Hydrogen to make glucose O 2 to the air ADP and NADP back to light reaction ATP and NADPH from light reaction GLUCOSE

Reactants • Diagram Light H 2 O CO 2 NADP + P Light Dependent Reaction Chloroplast O 2 ATP NADPH Products Calvin Cycle C 6 H 12 O 6 Glucose

Cellular Respiration • Process where energy of glucose is released in the cell to be used for life processes (movement, breathing, blood circulation, etc…)

• Respiration occurs in ALL cells • Takes place in the mitochondria • Can take place either with or without oxygen present.

Aerobic Respiration • requires oxygen • occurs in the mitochondria • Net total of 36 ATP produced • Formula C 6 H 12 O 6 + 6 O 2 glucose + oxygen Human cells contain a specialized structure – the mitochondrion – that generates energy. 6 CO 2 + 6 H 2 O + 36 ATP carbon dioxide + water + energy

STEP 1: Glycolysis -First pathway of respiration - ALL organisms perform this (aerobic AND anaerobic) -Takes place in the cytoplasm on enzymes -Splits glucose in half to form 2 pyruvic acid (pyruvate) -Gives off enough energy to make 2 ATP

STEP 2: Krebs Cycle -Also called the Citric Acid Cycle -pyruvic acid is broken down and CO 2 is released -Occurs in matrix of mitochondria STEP 3: Electron Transport Chain -electrons from Krebs Cycle converts ADP into ATP -Occurs along inner membrane (cristae) of mitochondria

• Diagram - Cellular Respiration Electrons carried in NADH Mitochondria In Cytoplasm Glucose Krebs Cycle Glycolysis 2 2 electrons carried in NADH Electron Transport Chain 32

Summary: st glycolysis 1 3 steps: 2 nd Krebs cycle 3 rd Electron Transport Chain (ETC)

Anaerobic Respiration or Fermentation: - pathway organisms use when no oxygen is available to the cell - Mostly unicellular organisms (low energy requirement) - Much less ATP produced than in aerobic respiration - Goes through glycolysis first, which makes 2 ATP - 2 kinds: Lactic Acid and Alcoholic Glucose Glycolysis 2 Pyruvate + 2 ATP ls & a m i ria An e t c e Ba m o s Bacte ria & Yea st Lactic acid Ethyl alcohol + CO 2

Lactic Acid Fermentation pyruvic acid lactic acid -Performed by muscle cells (animals) -Lactic acid is produced in the muscles during rapid exercise, when the body cannot supply enough oxygen to the tissues -causes a burning sensation in muscles -Also occurs in some bacteria -Used to create food products like yogurt and cheese

Alcohol fermentation Pyruvic acid ethyl alcohol + carbon dioxide -occurs in bacteria and yeast -Process used by baking and brewing industry -yeast produces CO 2 gas during fermentation to make dough rise and gives bread its holes

Cellular Respiration Diagram Anaerobic Respiration Cytoplasm C 6 H 12 O 6 glucose Alcoholic fermentation Bacteria, Yeast 2 ATP glycolysis Lactic acid fermentation Muscle cells 2 ATP Aerobic Respiration 36 ATP Krebs Cycle ETC Mitochondria

Photosynthesis and Respiration Products of one reaction are the Reactants of the other (and vice versa)

• Cells require a constant source of energy for life processes, but keep only a small amount of ATP on hand. Cells can make more ATP by using the energy stored in foods, like glucose. • The energy stored in glucose by photosynthesis is released by cellular respiration and repackaged into the energy of ATP.

Energy Flow: Producers photosynthesize and provide glucose for consumers Carbon Cycle: Producers remove CO 2 from atmosphere while consumer replaces CO 2 during respiration Water Cycle: Producers take water out of ecosystem and consumers produce water during respiration (also O 2 removed by producer and returned by consumer)