Biology Chapter 16 Final Exam Flashcards

Questions and Answers

In nucleotide excision repair, damaged DNA is excised by what enzyme(s)?

Nuclease

What is the function of helicase in DNA replication?

It untwists the double helix and separates the two DNA strands.

Who conducted the X-ray diffraction studies that were key to the discovery of the structure of DNA?

Franklin

What process repairs damage to a preexisting double helix?

Nucleotide excision repair Signup and view all the answers

What is a nucleic acid?

A polymer (polynucleotide) consisting of many nucleotide monomers. Signup and view all the answers

What is a polymer?

A long molecule consisting of many similar or identical monomers linked together. Signup and view all the answers

What are nucleotides?

The building block of nucleic acid, consisting of a five carbon sugar, a nitrogenous base, and a phosphate group. Signup and view all the answers

What does a DNA pyrimidine nucleotide consist of?

A deoxyribose and a phosphate. Signup and view all the answers

What is a difference between DNA and RNA?

DNA contains deoxyribose sugar, while RNA contains ribose. Signup and view all the answers

What are purines?

Guanine and Adenine Signup and view all the answers

What are pyrimidines?

Cytosine, Thymine, and Uracil. Signup and view all the answers

What are the nitrogenous bases in DNA?

Guanine, Adenine, Cytosine, Thymine Signup and view all the answers

What is the structure of DNA and RNA?

DNA consists of two polynucleotide chains, RNA usually consists of a single polynucleotide. Signup and view all the answers

What is a double helix?

The form of native DNA, referring to its two adjacent polynucleotide strands wound into a spiral shape. Signup and view all the answers

What is a gene?

A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses). Signup and view all the answers

DNA is single-stranded, whereas RNA is double-stranded.

False Signup and view all the answers

What is the base sequence of DNA?

The bases can be in any order, like the letters of the alphabet. Signup and view all the answers

Which nitrogenous base is found in DNA but not in RNA?

Thymine Signup and view all the answers

In a nucleotide, the nitrogenous base is attached to the sugar's _ carbon and the phosphate group is attached to the sugar's _ carbon.

1'... 5' Signup and view all the answers

Nucleic acids are assembled in the _____ direction.

5' to 3' Signup and view all the answers

In a DNA double helix, an adenine of one strand always pairs with a(n) _____ of the complementary strand.

Thymine Signup and view all the answers

The new DNA strand that grows continuously in the 5' to 3' direction is called the _____

Leading Strand Signup and view all the answers

During DNA replication, an open section of DNA, in which DNA polymerase can replicate DNA, is called a _____

Replication Fork Signup and view all the answers

After replication is complete, the new DNAs, called _____, are identical to each other.

Daughter DNA Signup and view all the answers

What is a mutation?

An error that occurs during the replication of DNA. Signup and view all the answers

In the Hershey and Chase experiment, what was the key finding?

Radioactively labeled phosphorus was present inside the infected bacteria. Signup and view all the answers

What are telomeres?

Repetitive DNA sequences present at the ends of eukaryotic chromosomes. Signup and view all the answers

What are the two types of bonds in DNA?

Covalent and Hydrogen Bonds. Signup and view all the answers

What is the shape of DNA?

Double helix or anti-parallel. Signup and view all the answers

What is the role of proteins in relation to DNA?

Packages up DNA, only necessary traits are expressed. Signup and view all the answers

When does DNA replicate?

During the S phase of interphase, only in cellular division (mitosis and meiosis). Signup and view all the answers

What do Chargaff's rules state?

In any species, there is an equal number of A and T bases, and C and G bases. Signup and view all the answers

How many non-coding DNA sequences does a person have?

97% Signup and view all the answers

How is DNA used in forensics?

DNA fingerprinting. Signup and view all the answers

Match the following enzymes with their functions:

Helicase = Unwinds parental double helix at replication forks DNA Polymerase = Joins nucleotides to form new DNA strands Ligase = Joins Okazaki fragments of lagging strand Primase = Synthesizes an RNA primer Signup and view all the answers

What are Okazaki fragments?

The short sections of DNA that are synthesized on the lagging strand. Signup and view all the answers

What is the difference between the parent and replicated daughter DNA?

Chromosomes get shorter as you age due to telomere region. Signup and view all the answers

How would you identify RNA?

RNA consists of ribose sugar that includes an oxygen. Signup and view all the answers

What is the leading strand?

The strand that flows continuously during DNA replication. Signup and view all the answers

What is the lagging strand?

The strand that is synthesized in Okazaki fragments. Signup and view all the answers

Study Notes

DNA Structure and Function

Nucleic acids are polymers, consisting of nucleotide monomers, essential for encoding genetic information. Types include DNA and RNA.
DNA consists of two antiparallel polynucleotide chains that form a double helix structure, stabilized by hydrogen bonds between nitrogenous bases.
DNA nucleotides comprise a deoxyribose sugar, a phosphate group, and nitrogenous bases (adenine, thymine, cytosine, guanine).
RNA differs from DNA by containing ribose sugar instead of deoxyribose and uracil instead of thymine; it usually exists as a single polynucleotide strand.

DNA Replication Process

DNA replication involves unwinding the double helix at replication forks, facilitated by helicase, which breaks hydrogen bonds between base pairs.
The replication fork is a structure where DNA is open for polymerase activity, allowing for the synthesis of new strands.
DNA polymerase III synthesizes new DNA in a 5’ to 3’ direction, which requires short segments (Okazaki fragments) on the lagging strand due to the antiparallel nature of DNA.
Leading strand is synthesized continuously towards the replication fork, while the lagging strand is synthesized in segments, later joined by DNA ligase.

Key Enzymes in DNA Replication

Helicase unwinds the DNA double helix, creating a replication fork.
Single-strand binding proteins stabilize the unwound DNA strands to prevent re-annealing.
Primase synthesizes short RNA primers necessary to initiate DNA synthesis.
DNA polymerases add nucleotides to the growing strand; DNA polymerase I replaces RNA primers with DNA.
DNA ligase connects Okazaki fragments on the lagging strand to form a continuous DNA strand.

Genetic Terms and Concepts

Genes are segments of DNA that encode instructions for protein synthesis and influence traits.
Mutations are errors in DNA replication that can be inherited if they occur in germ cells.
Telomeres protect the ends of chromosomes and are composed of repetitive DNA sequences.

Experimental Evidence for DNA Structure

Rosalind Franklin’s X-ray diffraction studies were crucial in revealing the helical structure of DNA.
The Hershey-Chase experiment demonstrated that DNA, not protein, is the genetic material, evidenced by radioactively labeled DNA entering bacterial cells.
Griffith’s transformation experiments with S. pneumoniae showed that genetic traits could be transferred and were heritable.

Important Concepts

Chargaff’s rules assert that the amounts of adenine equal thymine and cytosine equal guanine in DNA.
DNA replication is described as semiconservative, meaning each new double helix has one parental strand and one newly synthesized strand.
The structure of DNA can be likened to a pearl necklace, where the necklace is a polymer and each pearl symbolizes a nucleotide monomer.

DNA in Forensics

DNA fingerprinting is a method used for identification in forensic science, although it is not reliable for identical twins due to their identical genetic material.

Summary

The DNA double helix is fundamental to heredity, encoding instructions via a specific base sequence that determines cellular activities and functions.
Enzymatic actions in DNA replication are intricate and precise, ensuring accurate genetic transmission.

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Prepare for your Biology final exam with these flashcards covering Chapter 16. This quiz includes key concepts such as nucleotide excision repair, the role of helicase in DNA replication, and significant historical contributions to DNA research. Test your knowledge and ensure you're ready for the exam!