CELL ENERGY Energy – essential for life * All organisms must: 1. Be able to produce energy 2. Store energy 3. Use energy
LIFE PROCESSES THAT NEED ENERGY -active transport -movement -making proteins -nerve transmissions -maintaining homeostasis
ATP = Adenosine triphosphate (adenosine molecule & 3 phosphates) Form of energy usable by organisms - an energy molecule (like a candy bar, quick energy) Energy is stored in the phosphate to phosphate bond.
FORMING & BREAKING DOWN ATP Phosphate groups have negative charges (like charges repel) therefore, it takes a lot of energy to hold them together. Likewise, when a bond is broken, a lot of energy is released. ATP
HOW CELLS TAP INTO THE ENERGY STORED IN ATP Cell proteins have a site where ATP can bind 1. ATP Breaks down into Is released from the binding site Another phosphate may now bind there ADP Adenosine triphosphate to Adenosine diphosphate 3 phosphates 2 phosphates *Some cell functions (that don’t require much energy) can use ADP for an energy source
HOW PLANTS ACQUIRE THEIR ENERGY Autotrophic = organisms that make their own food (ex: plants) Photosynthesis = process where plants trap light energy to make glucose. Glucose (a carbohydrate) C 6 H 12 O 6
Which statement about autotrophs is true? A.Autotrophs eat grasses and other plant material. B.Autotrophs carry out photosynthesis but not respiration. C.Autotrophs use energy from the sun to make their own food. D.Autotrophs are always bacteria.
THE 2 PHASES OF PHOTOSYNTHESIS 1.Light Reactions (light dependent) Light Energy Chemical Energy (ATP) 2.Dark Reactions (Light independent) ATP Glucose
PHOTOSYNTHESIS EQUATION CO 2 + H 2 O + light energy C 6 H 12 O 6 + O 2 Carbon dioxide + Water+ light energy Glucose + Oxygen 6 CO 2 6 H 2 O C 6 H 12 O 6 Glucose 6 O 2 Photosynthesis Song
THE CHLOROPLAST & PIGMENTS The site of photosynthesis is the chloroplast Thylakoid Discs = located in the membrane of chloroplast is the site of light-dependent reactions.
Pigments in thylakoid discs absorb specific wavelengths of sunlight. Chlorophyll a & b (color pigment in chloroplast) absorb most wavelengths except green, therefore, green is reflected Why are plants green?
In the fall, trees reabsorb chlorophyll & allows other pigments to be seen. Why are fall leaves different colors?
Photosynthesis (6min video)
CELLULAR RESPIRATION Respiration = process by which cells break down food (glucose) to get energy Occurs in the mitochondria
C 6 H 12 O 6 + O 2 CO 2 + H 2 O + energy (Glucose) (Oxygen) (Carbon Dioxide) (water) (ATP) Energy from photosynthesis Glucose stored in plants O 2 released in air Glucose CO 2 Heat energy water
3 STAGES OF CELLULAR RESPIRATION First Phase (Anaerobic = oxygen is not required) (1) Glycolysis – Breaks glucose down * Yields: (a) 2 ATP molecules and (b) Pyruvic acid Occurs in the cytoplasm The glucose is small enough to enter the mitochondria and begin Phase 2
2 nd Phase (Aerobic = oxygen is required) (2) Citric Acid Cycle (or Krebs Cycle) Yields: (a) 2 ATP molecules And(b) acetic acid plus 24 H + atoms
3 rd Phase (Aerobic) (3) Electron Transport Chain * Yields: 24 H + atoms + O 2 34 ATP CELLULAR RESPIRATION YIELDS 38 ATP MOLECULES
Fermentation = occurs when cells are without oxygen for a short period of time Produces : ATP until oxygen is available.
2 Types 1.Lactic Acid The pyruvic acid from glycolysis becomes lactic acid & yields 2 ATP Lactic acid in muscles makes you feel tired and sore. Strenuous exercise used up O 2.
2. Fermentation (Alcoholic) Produces CO 2 and ethyl alcohol and 2 ATP Examples of how fermentation is useful: -yeast in bread (bread rises) - Yeast ferments grapes
Comparisons Photosynthesis VS Respiration 1.Stores EnergyReleases Energy 2. Makes FoodBreaks Down Food 3. Uses CO 2 and H 2 OUses Glucose and O 2 4. Makes Glucose and O 2 Makes CO 2 and H 2 O 5. Occurs in ChloroplastsOccurs in Mitochondria 6. Occurs only in LightOccurs all the time, light & dark
Combined Equations of Photosynthesis & Respiration CO 2 + H 2 O + energy Glucose + O 2 Photosynthesis Respiration
THE END