Exploring Experimental Design

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What are the criteria that scientists have to follow when designing their experiments?

An experiment must be designed to answer a specific question and provide objective results.

How are the Avery and Griffith experiments related to the rules of experimental design?

The Avery and Griffith experiments followed the criteria for experimental design.

What is the purpose of designing an experiment to answer a specific question?

The purpose is to determine something concrete that the scientist wants to know.

Why is it important for the data collected in an experiment to be measured in an objective way?

Objective measurements ensure that the results are unbiased and reliable. Signup and view all the answers

What are some factors to consider when designing a scientific experiment?

Factors to consider include the purpose of the experiment, data collection methods, and ensuring objective results. Signup and view all the answers

Can you give an example of a rule that builders have to follow when designing houses?

Builders have to follow rules such as including a roof, walls, doors, windows, plumbing, and electrical supply lines. Signup and view all the answers

What did Oswald Avery do to expose the insides of the dead S cells?

He lyse, or break open, the cell membranes with detergent. Signup and view all the answers

What was the resulting solution after breaking open the cell membranes?

A lysate, which was a solution of all the cell parts mixed together. Signup and view all the answers

What did Avery mix the lysate with?

The live R cells. Signup and view all the answers

What did Avery find when he mixed the lysate with the live R cells?

The mixture yielded live S cells, demonstrating that the transforming principle was something in the lysate, not something in the mouse. Signup and view all the answers

What did Avery test to determine if it was the transforming principle?

He tested whether the sugar coat was the transforming principle. Signup and view all the answers

What did Avery find when he destroyed the sugar coat inside the lysate?

The resulting mixture could still transform bacteria. Signup and view all the answers

What did Avery use to eat up all the protein molecules in the lysate?

Protein-digesting enzymes. Signup and view all the answers

What did Avery find when he destroyed all the proteins in the lysate?

The lysate was still capable of bacterial transformation. Signup and view all the answers

What were the main requirements that a scientist should consider when conducting an experiment?

A scientist should use numbers and units to describe findings, facilitate the collection of data, and control for multiple variables. Signup and view all the answers

What is a control in an experiment?

A control is a means of ensuring that only one factor is being tested at a time. Signup and view all the answers

What were the two strains of pneumococcus that Griffith worked with and how were they different?

Griffith worked with S bacteria (smooth) and R bacteria (rough). The S bacteria had a protective sugar coat, while the R bacteria lacked this coating. Signup and view all the answers

Why did mice always die when injected with the S bacteria?

Mice died when injected with the S bacteria because the mouse immune system couldn't penetrate the sugar coating. Signup and view all the answers

What did Griffith discover when he mixed living R cells with dead S cells and injected the mouse with the mixture?

When Griffith mixed living R cells with dead S cells and injected the mouse with the mixture, the mouse died and living S bacteria were found inside the mouse's blood. Signup and view all the answers

What was Oswald Avery's mission and what did he want to identify?

Avery's mission was to continue Griffith's work and identify the transforming principle responsible for the change in the R bacteria. Signup and view all the answers