Energy Flow in the Life of a Cell

Which of these supplies our cells with energy for cell metabolism? caffeine sugar oxygen water carbon dioxide other (explain) WORKTOGETHERWORKTOGETHER

Which of these supplies plant cells with energy for cell metabolism? sugar sunlight water oxygen carbon dioxide other (explain) WORKTOGETHERWORKTOGETHER

Our cells get energy from: 1.Caffeine 2.Sugar 3.Oxygen 4.Water 5.Carbon dioxide

Plant cells run their metabolism using which of the following? 1.Sunlight 2.Sugar 3.Water 4.Oxygen 5.Carbon dioxide

Energy “Energy” is the ability to do work, such as causing motion, or interaction between molecules. This is the idea of “energy” used in your textbook. “Energy” is used in an everyday sense to mean “alertness,” “strength,” or “vitality.”

“Energy” is a not a material. It is best described as a phenomenon. Energy can be measured a number of ways including: calories (food energy) degrees (heat energy) voltage (electrical potential)

Potential vs. Kinetic Energy Potential Kinetic

Potential energy is stored energy. Examples: coiled spring, energy in chemical bonds. Kinetic energy is energy released to do work. Examples: car in motion, heat, light, electrical current.

When we consume food as an energy source, the energy in the food is: 1.Potential energy 2.Kinetic energy

Energy Conversions gas Combustion by engine. 100 units chemical energy (concentrated) 75 units heat energy 25 units kinetic energy (motion) + All energy conversions involve a loss of energy, often as heat energy.

In living systems, too, energy conversions involve a loss of energy, about 90% at each level. energy stored in chemical bonds producerprimary consumersecondary consumer detritus feeders and decomposers heat HEAT

tertiary consumer (1 calorie) producer (1000 calories) primary consumer (100 calories) secondary consumer (10 calories) Top-level predators need huge territories. Use what you have just learned about energy conversion to explain this.

Why is only about 10% of energy passed from one organism to another in the food chain? If it takes about 30 acres of land to raise enough cattle to feed a family of five for a year, how much land would the family need if they went vegetarian? WORKTOGETHERWORKTOGETHER

Which of these is true about photosynthesis? 1.Photosynthesis makes energy. 2.Photosynthesis consumes energy.

Which of these is true about cellular respiration? 1.Cellular respiration creates energy. 2.Cellular respiration releases energy. 3.Cellular respiration consumes energy.

Endergonic reactions energy used products reactants Endergonic reactions consume (and may store) energy.

Endergonic Reaction Ammonium thiocyanate + Barium hydroxide

Inorganic mineral nutrients (nitrate, phosphate) are absorbed from soil and used in plant tissues. Energy is captured from sunlight. Oxygen is released. Sugar is synthesized and used in plant tissues. plant tissues, growth Carbon dioxide is absorbed from the air. Water is absorbed from soil, used in photosynthesis, and stored in cells. photosynthesis Photosynthesis is an example of an endergonic reaction. Explain why.

energy input C 6 H 12 O 6 (glucose) O 2 (oxygen) 6 CO 2 (carbon dioxide) 6 H 2 O (water) + + Producers (such as plants) take in light energy and use it to bind carbon, hydrogen, and oxygen into carbon- based compounds such as sugar. Sugar is stored (potential) energy used by Eukaryotes to make ATP for their cells.

Exergonic Reactions energy released products reactants Exergonic reactions release energy.

Exergonic Reaction

TERTIARY CONSUMER (4th trophic level) PRODUCER (1st trophic level) PRIMARY CONSUMER (2nd trophic level) SECONDARY CONSUMER (3rd trophic level) Metabolizing food (cellular respiration) is an example of an exergonic reaction. Explain why.

energy released C 6 H 12 O 6 (glucose) O 2 (oxygen) 6 CO 2 (carbon dioxide) 6 H 2 O (water) + + Both producers and consumers break down sugars and other carbon compounds to get usable energy for their cells. All Eukaryotes use the process of cellular respiration to break down sugar in order to make ATP.

progress of reaction energy released by burning glucose activation energy needed to ignite glucose CO 2 + H 2 O Burning glucose (sugar) : an exergonic reaction high low energy content of molecules glucose + O 2 Getting energy out of sugar by burning requires a high input of energy. What kind of molecule do cells use to lower the activation energy in order to use sugar?

ATP (a) Adenosine diphosphate (ADP) ribose Energy content Shorthand representations or "high-energy" bond adenine phosphate groups low "high-energy" bond phosphate groups or high (b) Adenosine triphosphate (ATP) What class of molecule is ATP?

ADP energy phosphateATP energy phosphateADP Which is exergonic and which is endergonic?

net exergonic “downhill” reaction glucose protein amino acids CO 2 + H 2 O + heat ADP + heat Coupled reaction: glucose breakdown and protein synthesis endergonic (ATP synthesis) exergonic (ATP breakdown) exergonic (glucose breakdown) endergonic (protein synthesis) What does this mean? (Think back to the first slides.)

Which process makes ATP for a plant cell to use? 1.Photosynthesis 2.Cellular respiration 3.Both 4.Neither

When do plants carry out photosynthesis? 1.Day only 2.Night only 3.Both day and night

When do plants carry out cellular respiration? 1.Day only 2.Night only 3.Day and night 4.Never. Plants only carry out photosynthesis.

Day Night When does a plant do photosynthesis (synthesizing organic, energy-rich molecules)? When does a plant do cellular respiration (breaking down organic molecules to release energy)? Photosynthesis Cellular Respiration

Remember... Photosynthesis does not “give a plant energy” or “make energy.” Photosynthesis uses energy to make organic molecules. Cellular respiration releases energy to the cells by breaking down organic molecules.

“Energy drinks” In a scientific sense, what is the source of real energy in these drinks? Why does a 0-calorie “energy” drink make no sense in science? WORKTOGETHERWORKTOGETHER

Recap Photosynthesis is an endergonic (energy-consuming) process. Cellular respiration is an exergonic (energy-releasing) process. Which process must ALL Eukaryotic organisms (including plants) do to make ATP?