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MCAT BIOLOGY EXAM QUESTIONS NEWEST
2025 ACTUAL EXAM COMPLETE 300
QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY
GRADED A+||BRAND NEW!!
What kind of bond connects the PO4 group to the 3rd carbon on the pentose sugar of the net nucleotide in the chain? - ANSWER-Phosphodiester
In a phosphodiester bond, which numbered carbons are connected by what? - ANSWER-PO4 group is connected to the 3rd carbon on the pentose sugar at one end, and the 5th carbon on the pentose sugar at the other end.
How do the nitrogenous bases bond to each other? - ANSWER- Hydrogen bonds
How many bonds are formed between A and T? - ANSWER-2
How many bonds are formed between C and G? - ANSWER-3 1 / 4
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Why is replication a semi-conservative replication? - ANSWER- Each original strand is added to one newly synthesized strand to form 2 new double helices.
In what direction does replication occur? - ANSWER- Bidirectional - the process begins at the middle of the double strand.
What enzyme separates the two strands of DNA? - ANSWER- DNA helicase
In what direction does DNA polymerase move? - ANSWER-3' to 5'
In what direction does DNA polymerase polymerize the complementary strand? - ANSWER-5' to 3'
In what direction does the replisome move? - ANSWER-It follows the direction of the unzipping strand.
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What is the replisome composed of? - ANSWER-Two replicative polymerase complexes, one of which synthesizes the leading strand, while the other synthesizes the lagging strand.The replisome is composed of a number of proteins including helicase, RFC, PCNA, gyrase/topoisomerase, SSB/RPA, primase, DNA polymerase I, RNAse H, and ligase.
Which polymerase polymerizes the leading strand? - ANSWER- Pol delta
Which polymerase polymerizes the lagging strand? - ANSWER- Pol alpha
What are okazaki fragments? - ANSWER-Relatively short fragment of DNA synthesized on the lagging strand during DNA replication.
How does RNA differ from DNA? - ANSWER-1) DEOXY in DNA 2) RNA is ss 3) RNA has U instead of T
What are the types of RNA? - ANSWER-mRNA 3 / 4
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tRNA rRNA
Where is RNA synthesized? - ANSWER-Nucleus rRNA = nucleolus
If RNA uses one strand for transcription, what does the other strand do? - ANSWER-Protects DNA from degradation.
What is the half-life of RNA? - ANSWER-30 minutes
Where does transcription occur? - ANSWER-Nucleus and mito matrix
When does transcription begin? - ANSWER-When initiation factors find a promoter.
What is a promoter? - ANSWER-A sequence of nucleotides on the DNA that designates a start point for trx.
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