Na + /K + Pumps and Beginning of Ch 8

Na + /K + ATPase Pumps Pumps Na + OUT of cell Pumps Na + OUT of cell Pumps K + IN to cell Pumps K + IN to cell Requires energy Requires energy Pumps ions against their concentration gradient Pumps ions against their concentration gradient

Because Na + /K + pumps create a concentration gradient of Na + outside of the cell, the flow of Na + back INTO the cell can be coupled with a sugar molecule, essentially giving the sugar molecule a free ride into the cell. Because Na + /K + pumps create a concentration gradient of Na + outside of the cell, the flow of Na + back INTO the cell can be coupled with a sugar molecule, essentially giving the sugar molecule a free ride into the cell. This is called coupled transport This is called coupled transport

Sodium potassium pump Sodium potassium pump ZKAR1Q&feature=related ZKAR1Q&feature=related ZKAR1Q&feature=related ZKAR1Q&feature=related

CHAPTER 8: Cellular Energy

Transformation of Energy 1 st Law of Thermodynamics:The Law of Conservation of Energy 1 st Law of Thermodynamics:The Law of Conservation of Energy Energy is never created nor destroyed; it merely changes form. Energy is never created nor destroyed; it merely changes form. - Rudolf Claussius

2 nd Law of Thermodynamics: 2 nd Law of Thermodynamics: Energy cannot change form without losing some of the useable energy Energy cannot change form without losing some of the useable energy This is in part because of the natural tendency of all systems to move toward chaos, or increase in entropy. This is in part because of the natural tendency of all systems to move toward chaos, or increase in entropy.

Autotrophs vs. Heterotrophs Auto – Gr. self Auto – Gr. self Hetero – Gr. other Hetero – Gr. other Troph – Gr. eating Troph – Gr. eating

Autotrophs make their own food Autotrophs make their own food Chemoautotroph – from chemical compounds Chemoautotroph – from chemical compounds Photoautotroph – from light Photoautotroph – from light Heterotrophs get food from outside sources Heterotrophs get food from outside sources We are heterotrophs We are heterotrophs

Metabolism ALL of the chemical reactions in a cell ALL of the chemical reactions in a cell Many reactions in cells are connected together and these are called metabolic pathways Many reactions in cells are connected together and these are called metabolic pathways Two types of metabolic pathway: Two types of metabolic pathway: Catabolic – release energy by breaking down large molecules Catabolic – release energy by breaking down large molecules Anabolic – use energy from catabolism to make larger molecules Anabolic – use energy from catabolism to make larger molecules

Photosynthesis An anabolic pathway An anabolic pathway Light energy from the sun is harnessed and converted into chemical energy Light energy from the sun is harnessed and converted into chemical energy Plants use light, CO 2, and water to make sugars and O 2 Plants use light, CO 2, and water to make sugars and O 2

Cellular Respiration A catabolic pathway that uses organic molecules (like food) to break down into energy that will be used by the cell A catabolic pathway that uses organic molecules (like food) to break down into energy that will be used by the cell Uses O 2 to break down molecules, byproducts include CO 2 and water Uses O 2 to break down molecules, byproducts include CO 2 and water

Again: Photosynthesis Photosynthesis Uses CO 2, light, and water and makes sugar Uses CO 2, light, and water and makes sugar Cellular respiration Cellular respiration Uses organic molecules (like sugar) and O 2 and produces CO 2 and water Uses organic molecules (like sugar) and O 2 and produces CO 2 and water

ATP – Adenosine triphosphate The most important source of chemical energy The most important source of chemical energy It is an energy-carrying molecule It is an energy-carrying molecule Found in all types of organisms Found in all types of organisms Releases energy when it loses a phosphate group becomes ADP Releases energy when it loses a phosphate group becomes ADP