Biology Notes Unit 3 section 2
Biology Notes Unit 3 section 2 Plants use photosynthesis to make their own food. Animals eat organisms for food. Food is not a direct source of energy, instead eukaryotes break down molecules from food to produce ATP. Cellular respiration releases chemical energy from sugars and other carbon based molecules to make ATP when oxygen is present.
Cellular respiration o is aerobic o Aerobic means that it needs oxygen to take place takes place in the mitochondria o mitochondria are called the powerhouse of a cell because they make most of a cells ATP
Mitochondria cannot directly make ATP from food. Foods need to be broken down into smaller molecules such as glucose. The glucose is then broken down. Steps of Cellular Respiration 1. Glycolysis literally means split the sweet process that splits glucose into 3 carbon molecules and makes 2 molecules of ATP along with pyruvates takes place in the cytoplasm is anaerobic anaerobic means that it does not need oxygen to take place Main stages of cellular respiration 2. Krebs Cycle Also known as the citric acid cycle Process that takes the 3 carbon molecules made in glycolysis are broken down and 2 molecules of ATP are made Takes place in the mitochondria Is not considered to be aerobic or anaerobic but could not happen without the presence of oxygen Carbon dioxide is released 3. Electron Transport Chain Process that transfers energy down a chain of proteins and 32 molecules of ATP is made along with water and heat Takes place in the mitochondria Aerobic
Proteins used here are supplied by NADH and FADH2
Products of all the steps and stages of cellular respiration are
Carbon dioxide from krebs cycle Water from the electron transport chain 36-38 ATP molecules for every glucose molecule o 2 from glycolysis o 2 from krebs cycle o 34 from electron transport chain
Organelles for process Reactants Electron transport chain Cycle of chemical reactions
Products
Photosynthesis Chloroplast Carbon dioxide and water Proteins within thylakoid membrane Calvin cycle in stroma of chloroplasts builds sugar molecules Sugars (glucose) and oxygen
Cellular Respiration mitochondria Sugars (glucose) and oxygen Proteins within inner mitochondrial membrane Krebs cycle in matrix of mitochondria breaks down carbon based molecules Carbon dioxide and water
When glycolysis has taken place depending on the presence or lack of oxygen determines what will happen next.
If oxygen is present then cellular respiration will begin If no oxygen is present then fermentation will take place.
Fermentation does not make ATP, but allows glycolysis to continue.
There are 2 types of fermentation that will take place if there is no oxygen available for cellular respiration to take place. 1. Lactic Acid Fermentation 2. Alcoholic Fermentation Lactic Acid Fermentation
They pyruvic acid from glycolysis is reduced to lactic acid by NADH Commonly occurs in muscle cells when they don’t receive the oxygen they need to perform aerobic respiration o Occurs when we work them to hard o The muscle cells still need energy so they perform glycolysis but cannot perform aerobic respiration o Muscle cramps will start until oxygen gets to the muscle cells
Alcoholic Fermentation
They pyruvic acid from glycolysis is reduced to ethyl alcohol Commonly occurs in yeast Carbon dioxide and alcohol are the by-products of this fermentation.
o Alcohol remains in the liquid which is great for making an alcoholic beverage but not for the yeast cells, as the yeast dies when the alcohol exceeds its tolerance level
Cellular respiration o is aerobic o Aerobic means that it needs oxygen to take place takes place in the mitochondria o mitochondria are called the powerhouse of a cell because they make most of a cells ATP
Mitochondria cannot directly make ATP from food. Foods need to be broken down into smaller molecules such as glucose. The glucose is then broken down. Steps of Cellular Respiration 1. Glycolysis literally means split the sweet process that splits glucose into 3 carbon molecules and makes 2 molecules of ATP along with pyruvates takes place in the cytoplasm is anaerobic anaerobic means that it does not need oxygen to take place Main stages of cellular respiration 2. Krebs Cycle Also known as the citric acid cycle Process that takes the 3 carbon molecules made in glycolysis are broken down and 2 molecules of ATP are made Takes place in the mitochondria Is not considered to be aerobic or anaerobic but could not happen without the presence of oxygen Carbon dioxide is released 3. Electron Transport Chain Process that transfers energy down a chain of proteins and 32 molecules of ATP is made along with water and heat Takes place in the mitochondria Aerobic
Proteins used here are supplied by NADH and FADH2
Products of all the steps and stages of cellular respiration are
Carbon dioxide from krebs cycle Water from the electron transport chain 36-38 ATP molecules for every glucose molecule o 2 from glycolysis o 2 from krebs cycle o 34 from electron transport chain
Organelles for process Reactants Electron transport chain Cycle of chemical reactions
Products
Photosynthesis Chloroplast Carbon dioxide and water Proteins within thylakoid membrane Calvin cycle in stroma of chloroplasts builds sugar molecules Sugars (glucose) and oxygen
Cellular Respiration mitochondria Sugars (glucose) and oxygen Proteins within inner mitochondrial membrane Krebs cycle in matrix of mitochondria breaks down carbon based molecules Carbon dioxide and water
When glycolysis has taken place depending on the presence or lack of oxygen determines what will happen next.
If oxygen is present then cellular respiration will begin If no oxygen is present then fermentation will take place.
Fermentation does not make ATP, but allows glycolysis to continue.
There are 2 types of fermentation that will take place if there is no oxygen available for cellular respiration to take place. 1. Lactic Acid Fermentation 2. Alcoholic Fermentation Lactic Acid Fermentation
They pyruvic acid from glycolysis is reduced to lactic acid by NADH Commonly occurs in muscle cells when they don’t receive the oxygen they need to perform aerobic respiration o Occurs when we work them to hard o The muscle cells still need energy so they perform glycolysis but cannot perform aerobic respiration o Muscle cramps will start until oxygen gets to the muscle cells
Alcoholic Fermentation
They pyruvic acid from glycolysis is reduced to ethyl alcohol Commonly occurs in yeast Carbon dioxide and alcohol are the by-products of this fermentation.
o Alcohol remains in the liquid which is great for making an alcoholic beverage but not for the yeast cells, as the yeast dies when the alcohol exceeds its tolerance level
