Chemistry and Genetic Mutations Chapter 22

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Questions and Answers

What is the primary function of a vaccine in relation to viruses?

To replace viral DNA with healthy DNA

To directly kill the virus in the body

To stimulate the immune system to produce antibodies (correct)

To prevent the initial invasion of the host by the virus

Which of the following statements is true about retroviruses?

They contain only RNA and replicate independently.

They synthesize viral DNA through reverse transcription. (correct)

They do not transcribe RNA for protein synthesis.

They are incapable of causing diseases in humans.

What process is utilized to separate DNA fragments by size?

Chromatography

Polymerase chain reaction

Filtration

Gel electrophoresis (correct)

What characterizes a virus as being incapable of independent replication?

Dependency on the host for replication Signup and view all the answers

Which virus is associated with Acquired Immunodeficiency Syndrome (AIDS)?

Human immunodeficiency virus (HIV) Signup and view all the answers

What is a point mutation?

The substitution of one nucleotide for another. Signup and view all the answers

Which type of mutation generally has no effect on the resulting protein?

Silent mutation Signup and view all the answers

What can result from a deletion mutation?

Loss of one or more nucleotides from DNA. Signup and view all the answers

What is the effect of a mutation that introduces a stop codon?

The remainder of the protein will not be synthesized. Signup and view all the answers

Which of these statements is true regarding genetic diseases?

They can result from mutations that produce defective protein synthesis. Signup and view all the answers

What is required to form recombinant DNA?

A gene from a second organism and a DNA cleaving enzyme. Signup and view all the answers

Which of the following diseases is caused by a mutation in the CFTR gene?

Cystic fibrosis Signup and view all the answers

What is a characteristic of recombinant DNA?

It contains segments from more than one source. Signup and view all the answers

What is formed when a plasmid DNA and human DNA with matching sticky ends are combined?

A larger double strand of recombinant DNA Signup and view all the answers

Which of the following is NOT a component needed for Polymerase Chain Reaction (PCR)?

Protein molecules Signup and view all the answers

What does the heating step in PCR accomplish?

It unwinds the double helix into single strands Signup and view all the answers

After how many cycles of PCR can you produce approximately 1,000,000 copies of the DNA segment?

20 cycles Signup and view all the answers

Which of the following best describes the purpose of restriction enzymes in DNA fingerprinting?

To cut DNA into manageable fragments Signup and view all the answers

What role do primers play in the PCR process?

They are complementary to the DNA segment's ends Signup and view all the answers

What does the term "sticky ends" refer to in DNA manipulation?

Single-stranded ends that can bond with complementary DNA Signup and view all the answers

Which type of cell can be used to obtain a DNA fingerprint?

Any type of cell, including skin, saliva, and blood Signup and view all the answers

Study Notes

Chapter 22 Lecture Outline

Topics covered in the chapter include general, organic, and biological chemistry.
Key chemical substances mentioned include glucose, uric acid, calcium, cholesterol, triglycerides, HDL cholesterol, and LDL cholesterol.

Mutations and Genetic Disease

A mutation is a change in the nucleotide sequence of DNA.
Some mutations are random, others are caused by mutagens.
A point mutation involves substituting one nucleotide for another in DNA.
- Example: Original DNA: GAGTTC, Point mutation: GACTTC (replacing G with C).
A deletion mutation occurs when one or more nucleotides are lost from a DNA molecule.
- Example: Original DNA: GAGTTC, Deletion mutation: GATTC (loss of G).
An insertion mutation occurs when one or more nucleotides are added to a DNA molecule.
- Example: Original DNA: GAGTTC, Insertion mutation: GAGCTTC (adding C).
A silent mutation has minimal effect on the organism because the resulting amino acid remains the same.
- Example: Original DNA: CTT, resulting in GAA (Glu); Point mutation: CTC, resulting in GAG (Glu). The mutation has no effect.
A mutation creating a different amino acid usually has a moderate effect on the protein.
- Example: Original DNA: CTT, resulting in GAA (Glu); Point mutation: CAT, resulting in GUA (Val). A different amino acid is produced.
Some mutations, like those in hemoglobin, can cause fatal diseases. An example is sickle cell anemia.
A mutation generating a stop codon often results in a damaged protein.
- Example: Original DNA: CTT, resulting in GAA (Glu); Point mutation: ATT, resulting in UAA (Stop). The protein is incomplete and may be non-functional.

Genetic Diseases

A genetic disease is caused by a mutation that creates a deficiency or defective protein synthesis and can be passed through generations.
Cystic fibrosis is caused by defective CFTR, affecting lung mucus and pancreatic secretions.
Galactosemia is a deficiency in an enzyme needed for galactose metabolism and may lead to mental retardation.
Table 22.5 lists additional genetic diseases and their characteristics, including Tay-Sachs disease (defective hexosaminidase A), sickle cell anemia (defective hemoglobin), phenylketonuria (deficiency in phenylalanine hydroxylase), and Huntington's disease (defect in the Htt protein).

Recombinant DNA General Principles

Recombinant DNA contains segments from more than one source.
Three key elements are needed to create recombinant DNA:
- 1. A DNA molecule to insert the new segment into.
- 1. An enzyme (like EcoRI) that cuts DNA at specific locations.
- 1. A gene from a second organism to insert into the initial DNA molecule.
Bacterial plasmid DNA is cut by restriction endonuclease EcoRI (example) to create sticky ends suitable for bonding.
A second sample of human DNA is also cut with the same enzyme (EcoRI).
The fragmented DNA pieces bond together (using DNA ligase) creating a chain containing the new segment.
This chain is larger than the original due to the addition.

Recombinant DNA Polymerase Chain Reaction (PCR)

PCR amplifies a specific segment of DNA to produce millions of copies.
Four elements are required for PCR:
- 1. The target DNA segment to be copied.
- 1. Primers complementary to the segment's ends.
- 1. DNA polymerase enzyme to synthesize the complementary strand.
- 1. Nucleotide building blocks (A, T, C, G).
Steps in PCR include initial heating to unwind the DNA, adding primers complementary to the sequence at either end, and using DNA polymerase to synthesize the new strands, doubling the amount of DNA, in each cycle.

DNA Fingerprinting

DNA fingerprinting uses an individual's unique DNA to identify them.
Any cell type (skin, saliva, blood, etc.) can be used.
DNA is amplified by PCR and then cut by restriction enzymes.
DNA fragments are separated by size using gel electrophoresis.
Separated DNA is visualized on X-ray film.

Viruses

A virus is an infectious agent with DNA or RNA within a protein coat.
Viruses are incapable of replicating alone and invade a host organism.
Examples of prevalent viral diseases are the common cold, influenza, and herpes.
A vaccine is an inactive form of a virus that triggers an immune response, producing antibodies to ward off the virus.
Retroviruses are viruses with an RNA core, such as HIV, which causes AIDS.
Retroviruses synthesize viral DNA through reverse transcription, and then transcribe RNA, which produces new retroviral particles.

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Description

Explore Chapter 22 focusing on the intersection of chemistry and genetics. This quiz covers essential topics such as chemical substances like glucose and cholesterol, as well as various types of mutations and their implications on genetic diseases. Test your knowledge on these fundamental concepts of organic and biological chemistry.