Cellular Respiration

Where do organisms get their energy?  Organisms get the energy they need from food.

Chemical Energy and Food  Food molecules contain chemical energy that is released when its chemical bonds are broken.

Chemical Food and Energy  Energy stored in food is expressed in units of calories.  A Calorie is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius.  1000 calories = 1 kilocalorie, or Calorie.

Chemical Energy in Food  Cells use all sorts of molecules for food, including fats, proteins, and carbohydrates. The energy stored in each of these molecules varies.  Cells break down food molecules gradually and use the energy stored in the chemical bonds to produce compounds such as ATP that power the activities of the cell.

Cellular Respiration  Cellular respiration is the process that releases energy from food in the presence of oxygen.  ALL living organisms undergo cellular respiration.

The Equation 6 C 6 H 12 O 6 + O 2 CO 2 + H 2 O energy (ATP)

Cellular Respiration In words: Oxygen + Glucose  Carbon dioxide + Water + Energy

What are the reactants in the equation for cellular respiration? a).oxygen and lactic acid b).carbon dioxide and water c). glucose and oxygen d).water and glucose

In the process of cellular respiration, the chemical energy stored inside the bonds of glucose is converted to what type of energy? a. sunlight b. energy stored in ATP c. mechanical energy d. movement

Stages of Cellular Respiration  The three main stages of cellular respiration are glycolysis, the Krebs cycle, and the electron transport chain.

Oxygen and Energy  Pathways of cellular respiration that require oxygen are called aerobic.  The Krebs cycle and electron transport chain are both aerobic processes.  Both processes take place inside the mitochondria.

Oxygen and Energy  Gylcolysis is an anaerobic process.  It does not directly require oxygen, nor does it rely on an oxygen-requiring process to run.  However, it is still considered part of cellular respiration.  Glycolysis takes place in the cytoplasm of a cell.

What are the names of the three processes of cellular respiration? A) Gycolysis, Krebs Cycle and ATPases B) Krebs Cycle, Electron Transport Chain and Photosynthesis C) Glycolysis, Krebs Cycle and Electron Transport Chain D) Electron Transport Chain, Glycolysis and Photosynthesis

Which of the cellular respiration processes take place in the cytoplasm? A) Glycolysis B) Krebs Cycle C) Electron Transport Chain

Where in the cell does the Krebs Cycle and the Electron Transport Chain take place? A)Cytoplasm B) Mitochondrion C) Nucleus D) Cell membrane

Which type of respiration requires oxygen? A) Aerobic B) Anaerobic

Scientific Methodology  Scientific methodology involves observing and asking questions, making inferences and forming hypotheses, conducting controlled experiments, collecting and analyzing data, and drawing conclusions.

Observing and Asking Questions  Scientific investigations begin with observation, the act of noticing and describing events or processes in a careful, orderly way.  For example, researchers observed that marsh grass grows taller in some places than others. This observation led to a question: Why do marsh grasses grow to different heights in different places?

Inferring and Forming a Hypothesis  After posing questions, scientists use further observations to make inferences, or logical interpretations based on what is already known.  Inference can lead to a hypothesis, or a scientific explanation for a set of observations that can be tested in ways that support or reject it.

Designing Controlled Experiments  Testing a scientific hypothesis often involves designing an experiment that keeps track of various factors that can change, or variables.  Examples of variables include temperature, light, time, and availability of nutrients.

Designing a Controlled Experiment  Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed.  All other variables should be kept unchanged, or controlled.  This type of experiment is called a controlled experiment.

Why is controlling an experiment important?