Label 6 test tubes or small cups:
Tube 5, Tube 6 control A9. Observe the milk in each of the five tubes after the 15 minute period and record your observations in your notebook. Do your results support either of your hypotheses?
Part B- pH Each enzyme has an optimal pH. A change in pH can alter the ionization of the R groups of the amino acids. When the charges on the amino acids change, hydrogen bonding within the protein molecule change and the molecule changes shape.
The new shape may not be effective. The diagram below shows that pepsin functions best in an acid environment. This makes sense because pepsin is an enzyme that is normally found in the stomach where the pH is low due to the presence of hydrochloric acid.
Trypsin is found in the duodenumand therefore, its optimum pH is in the neutral range to match the pH of the duodenum. Most cells form hydrogen peroxide H2O2 as a waste product of aerobic respiration. Hydrogen peroxide is toxic and must be converted to water and oxygen by the enzyme catalase.
Hydrogen peroxide is also commonly used as a household disinfectant. It bubbles when it is applied to cuts and scrapes because catalase is present in the fluids of the broken cells.
As the equation above shows, the bubbles are oxygen gas O2. In the experiment below, bubbling will be used as an indication that a reaction is occurring.
A faster reaction will have more bubbling. Predict how pH will affect the rate of reaction in the three different situations described below and write your hypothesis or hypotheses in your notebook.
At this point, you do not know if your hypothesis is true or false. It is acceptable to create a hypothesis which will be shown to be false. Mark three test tubes with a wax pencil 3 cm from the bottom and 6 cm from the bottom.
Add 3 cm of hydrogen peroxide to each tube. Fill one of the tubes to the 6 cm mark with 5 m HCl. Fill another tube to the 6 cm mark with 5 m NaOH. Fill the third tube to the 6 cm mark with distilled water. Cut three strips of potato that are approximately 3 cm long.
The strips should ne cut thin enough to easily fit into a test tube. Place one of the strips of potato into each of the three tubes that you prepared in steps above. Write your observation of the amount of bubbling in your notebook.Pearson, as an active contributor to the biology learning community, is pleased to provide free access to the Classic edition of The Biology Place to all educators and their students.
The purpose of the activities is to help you review material you have already studied in class or have read in your text. Biology IB HL 1. Previous IB Exam Essay Questions: Unit 3 Use these model essay question responses to prepare for essay questions on your in class tests, as well as the IB Examination, Paper 2.
Explain how proteins act as enzymes, including control by feedback inhibition in allosteric enzymes. The pattern of majority of biology exams are multiple choice questions.
Here we are providing you with topic wise MCQs helping you to learn the topic during your preparation itself. We have included many questions appeared in different biology exams. Items 10–11 refer to the following graph which shows the activity of two enzymes in the human digestive system.
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State the functions of cell structures - Biology Caribbean CXC questions. At Pass My CXC you have the opportunity to reveiw questions from past papers, take CXC test questions, submit CXC problems, receive answers and instructions from secondary school teachers and network with your peers from secondary school.