PBS EOC Review

What is the structure of purines?

• A single 5 carbon ring

• A single 6 carbon ring

• A double ring with one six carbon and one 5 carbon ring

• A double ring with two four carbon rings

Answer explanation

Purines are characterized by a double ring structure, consisting of one six-membered carbon ring and one five-membered carbon ring. This distinguishes them from pyrimidines, which have a single six-membered ring.

What is the role of an restriction enzyme?

• Create a pattern of a person's DNA

• Act as molecular scissors that cut DNA

• Separate and compare different DNA sequences

• Produce millions of copies of DNA

Answer explanation

Restriction enzymes act as molecular scissors that cut DNA at specific sequences, allowing for manipulation and analysis of genetic material. This is essential in genetic engineering and molecular biology.

_______ has a double ring structure and is an example of a _______

• adenine... purine

• thymine... pyrimidine

• cytosine.....purine

• guanine....pyrimidine

Answer explanation

Adenine has a double ring structure, classifying it as a purine. In contrast, thymine and cytosine are single-ring structures, making them pyrimidines. Thus, the correct answer is adenine... purine.

Who should the lawyer request a warrant for?

• Suspect 1

• Suspect 2

• Suspect 3

• Suspect 4

Answer explanation

The lawyer should request a warrant for Suspect 4 because they have the strongest evidence against them, indicating a higher likelihood of involvement in the crime compared to the other suspects.

A student wants to test the effects of type of exercise on heart rate.  What is the dependent variable?

• heart rate

• type of exercise

• amount of exercise

• time of day exercise occurs

Answer explanation

The dependent variable is what is measured in an experiment. In this case, the student is measuring heart rate to see how it is affected by different types of exercise, making heart rate the correct choice.

How many rings does a pyrimidine have?

• 1

• 2

• 3

• 4

Answer explanation

A pyrimidine has one ring structure. It is a six-membered ring containing two nitrogen atoms and four carbon atoms, making the correct answer 1.

Mr. Krabbs is trying a new money making scheme.  On Tuesdays he is selling his crabby patties on colored buns.  He usually averages 25 customers per day.  On Tuesdays he now averages 27 customers. 
What was the control?

• The customers 

• The crabby patty

• The colored buns

• The number of customers

Answer explanation

The control in this scenario is the crabby patty, as it is the main product being sold. The increase in customers on Tuesdays is compared to the usual sales, making the crabby patty the baseline for evaluating the impact of colored buns.

What is produced as a result of DNA being cut by restriction enzymes?

• Restriction Fragment Length Polymorphisms 

• Restriction Fragmented Long Palindromes

• Polymerase Chain Reaction

• Polymorphic Fragment Chains

Answer explanation

Restriction enzymes cut DNA at specific sequences, resulting in fragments of varying lengths. These variations in fragment lengths are known as Restriction Fragment Length Polymorphisms (RFLPs), making this the correct answer.

DNA is ________ charged and migrates to the ________ end of the gel.

• negative, positive

• positive, negative

• negative, neutral

• positive, neutral

Answer explanation

DNA is negatively charged due to its phosphate backbone. During gel electrophoresis, it migrates towards the positive electrode, making the correct answer 'negative, positive'.

What is the backbone of DNA made out of?

• Phosphates and sugars

• Basepairs

• Deoxyribose

• Hydrogen bonds

Answer explanation

The backbone of DNA is composed of alternating phosphates and deoxyribose sugars. This structure provides stability and support for the genetic information encoded in the base pairs.