086 Lecture Notes - Lecture 3: Brownian Motion, Fractional Distillation, Centrifugation

27 views8 pages

sishmeet259

19 Apr 2023

School

University of Delhi - DU

Department

Animal Science

Course

086

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Chapter 2 is matter around us pure . Key concepts : [ *rating as per the significance of concept : pure substance & mixture, types of mixtures, methods of separation of mixtures, concentration & types of solutions, physical & chemical changes, alloys. Basic knowledge of particle nature of matter. Conceptual levels of comprehension on the basis of feedback taken from the students. Mixture consists of two or type of substance . more pure substances. Mixture can be separated into separated into other substances by physical methods. its components by physical methods. Mixture shows the definite properties. properties of its components. Elements are made up of one kind of atoms only. Compounds are made up of one kind of molecules only. [ refer ncert text book tab. 2. 2, page 26] Q. 3 classify the following as element , compound and mixture: iron , sea water , milk. Mixtures can also be grouped: on the basis of their physical states:

Related Questions

Question 2

Humus comes from

A clay soil

B dead plants and animals

C bedrock

Question 3

Which statement best describes soil?

A a mixture of weathered rock and decomposed organic material

B a mixture of sediments weathered into different grain sizes

C a mixture of different types of rock particles weathered from different types of bedrock

Question 5

Which best describes the composition of a typical soil's A horizon?

A humus and small rock fragments

B mostly decomposing organic matter

C large, mostly unweathered pieces of rock

dndndjdj282

In this project you address 5 related to the environment. Choose which issue you will work to solve with the project. Write a guiding question.

Student Work: Global Issue

Student Work: Essential Question

Student Work: Misconception and Counterclaim

Self-Assessment: Asking Questions

Level

Rationale - Write a short paragraph justifying the numerical level score you chose using key terms from the rubric and examples from your work.

Checkpoint Directions

Choose a global issue to research for this project:

Check for Resources and Activities under this checkpoint that will help you complete this checkpoint.

Go to the GIN 20 Global Issues page and choose one of the issues from the first column, “Sharing our planet: Issues involving the global commons”. There are six to choose from. You can click on the issues to read more about them.

Describe the issue you chose (your own words in complete sentences) in the box above, Student Work: Global Issue.

In your description connect your issue to human population growth.

Write an essential question. Use the rubric as a guide. Write your question in the box above, Student Work: Essential Question. Your question should be related to a solution for your issue.

Identify a misconception about your issue and critique it.

Use the attached Resource: Common Environmental Misconceptions if you need help identifying a misconception.

Research the science concepts related to the misconception.

Write your critique. Part of your critique must address science concepts and/or data. Check with your teacher if you think yours is an exception.

Your critique should conclude with an explanation for why it is a misconception and what the correct concept it.

Checkpoint Checklist

Done

These things must be done or included for this CP to be completed.

Use the rubric for additional guidance.

Issue from GIN Global Issues: Sharing our planet: Issues involving the global commons chosen and described.

Essential question written to guide your research. The question should focus on a solution.

One misconception identified and a critique is written about it.

The critique of the misconception leads to an explanation of the correct concept based on science facts and/or data.

123

Do Enzymes Physically Attach to Their Substrates?

When scientists first began to examine the chemical activities of organisms, no one knew that biochemical reactions were catalyzed by enzymes. The first enzyme was discovered in 1833 by French chemist Anselme Payen. He was studying how beer is made from barley: First, barley is pressed and gently heated so its starches break down into simple two-sugar units; then yeasts convert these units into ethanol. Payen found that the initial breakdown requires a chemical factor that is not alive and that does not seem to be used up during the process-a catalyst. He called this first enzyme diastase (we call it amylase today).

Did this catalyst operate at a distance, increasing the reaction rate all around it, much as raising the temperature of nearby molecules might do? Or did it use physical contact, actually attaching to the molecules whose reaction it catalyzed (its "substrate")?

The answer was discovered in 1903 by French chemist Victor Henri. He saw that the hypothesis that an enzyme physically binds to its substrate makes a clear and testable prediction: In a solution of substrate and enzyme, there must be a maximum reaction rate. When all the enzyme molecules are working full tilt, the reaction simply cannot go any faster, no matter how much more substrate you add to the solution. To test this prediction. Henri carried out the experiment whose results you see in the graph, measuring the reaction rate (V) of diastase at different substrate concentrations (S).

Analysis

1. Making Inferences As S increases, does V increase? If so, in what manner-steadily, or by smaller and smaller amounts? Is there a maximum reaction rate?

2. Drawing Conclusions Does this result provide support for the hypothesis that an enzyme binds physically to its substrate? Explain. If the hypothesis were incorrect, what would you expect the graph to look like?

3. Further Analysis If the smaller amounts by which V increases are strictly the result of fewer unoccupied enzymes being available at higher values of S, then the curve in Henri's experiment should show a pure exponential decline in V-mathematically, meaning a reciprocal plot (1/V versus 1/S) should be a straight line. If some other factor is also at work that reacts differently to substrate concentration, then the reciprocal plot would curve upward or downward. Fill in the reciprocal values in the table to the right, and then plot the values on the lower graph (1/S on the x axis and 1/V on the y axis). Is a reciprocal plot of Henri's data a straight line?

jadadial16

086 Lecture Notes - Lecture 3: Brownian Motion, Fractional Distillation, Centrifugation

Document Summary

Get access

Related Documents

CHEM 120A Lecture Notes - Lecture 1: Distillation, Mass Ratio, Ernest Rutherford

CHEM 1500 Study Guide - Midterm Guide: Unified Atomic Mass Unit, Fahrenheit, Chemical Decomposition

CHEM 177 Lecture Notes - Lecture 1: Astatine, Distillation, Barium

Related Questions