Objectives

Quiz 1:

1. Distinguish between DNA and RNA.

2. Explain the process of transcription.

3. Apply knowledge of transcription to predict an mRNA sequence given information about a DNA sequence.

4. Explain the overall process of protein synthesis (transcription and translation).

5. Explain the roles of the rough endoplasmic reticulum (rough ER) and golgi apparatus, and be able to correctly sequence the involvement of various cell organelles in the process of producing and exporting a protein.

6. Apply knowledge of translation to predict a tRNA sequence given information about an mRNA sequence.

7. Apply knowledge of translation to predict an amino acid sequence given information about a tRNA sequence.

8. Distinguish between point/substitution and frameshift/insertion/deletion mutations, and predict their effects on an amino acid sequence.

Vocabulary

Anticodon

Amino acid

Codon

Coding strand/Gene strand

Frameshift mutation

• Insertion

• Deletion

Golgi apparatus (or complex, bodies)

Messenger RNA (mRNA)

Mutation

Nucleus

Point or substitution mutation

• Missense

• Nonsense

• Silent

Polypeptide

Protein

Protein Synthesis

Ribosomal RNA (rRNA)

Ribose

Ribosome

RNA

Rough endoplasmic reticulum

Smooth endoplasmic reticulum

Start codon

Stop codon

Template strand

Transcription

Translation

Transfer RNA (tRNA)

Uracil

Vesicle

Textbook Reference

6.3: DNA directs the production of proteins via RNA

6.4: Genetic information flows from DNA to RNA to protein

6.5: Transcription creates a molecule of RNA from a molecule of DNA

6.6: Translation involves the coordination of three kinds of RNA

6.7: Translation creates a molecule of protein via the genetic code

6.10: Mutations can have a wide range of effects

Relevant Files

Sample MCAS Questions

Quiz 1:

1. Individuals with one form of lactose intolerance do not produce the enzyme lactase because the gene coding for the production of lactase is shut off in their cells. This means that which of the following processes does not occur for the gene?

A. Hydrogenation

B. Mutation

C. Replication

D. Transcription

2. The mold Aspergillus flavus grows on grain. A. flavus produces a toxin that binds to DNA in the bodies of animals that eat the grain. The binding of the toxin to DNA blocks transcription, so it directly interferes with the ability of an animal cell to do which of the following?

A. transport glucose across the cell membrane into the cytoplasm

B. produce ATP using energy released from glucose and other nutrients

C. transfer proteins from the endoplasmic reticulum to Golgi complexes

D. send protein-building instructions from the nucleus to the cytoplasm and ribosomes

3. Which of the following features of DNA is most important in determining the phenotype of an organism?

A. The direction of the helical twist

B. The number of deoxyribose sugars

C. The sequence of nitrogenous bases

D. The strength of the hydrogen bonds

4. The diagram below shows a strand of DNA matched to a strand of messenger RNA.

What process does this diagram represent?

A. mutation

B. respiration

C. transcription

D. translation

5. The diagram below shows the final steps of a biochemical pathway used by the bacterium Serratia marcescens to produce a red pigment molecule. Letters X, Y, and Z represent intermediate molecules produced in the pathway. Four enzymes are also involved in the pathway, as shown.

A mutant strain of S. marcescens produces molecules X and Y but does not produce the red pigment molecule or molecule Z. Based on this result, it can be concluded that there must be a mutation in the gene coding for which enzyme?

A. Enzyme 1

B. Enzyme 2

C. Enzyme 3

D. Enzyme 4

6. The diagram below represents part of a process that occurs in cells.

Which process is represented?

A. Meiosis

B. Osmosis

C. Replication

D. Translation

7. Which of the following best describes the result of a mutation in an organism's DNA?

A. The mutation may produce a zygote.

B. The mutation may cause phenotypic change.

C. The mutation causes damage when it occurs.

D. The mutation creates entirely new organisms.

8. In phenylketonuria (PKU), an enzyme that converts one amino acid into another does not work properly. Which of the following is the most likely cause of this genetic condition?

A. an error in the transcription of the gene for the enzyme

B. a mutation in the DNA sequence that codes for the enzyme

C. an excess of the amino acids necessary to produce the enzyme

D. a structural variation in the amino acid modified by the enzyme

9. Ovalbumin is a protein found in eggs. Which of the following best describes the molecular structure of ovalbumin?

A. a group of six carbon atoms joined in a ring

B. a chain of amino acids folded and twisted into a molecule

C. a set of three fatty acids attached to a molecule of glycerol

D. a sequence of nitrogenous bases attached to a sugar-phosphate backbone

10. Fireflies produce light inside their bodies. The enzyme luciferase is involved in the reaction that produces the light. Scientists have isolated the luciferase gene. If a scientist inserts the luciferase gene into the DNA of cells from another organism. If these cells produce light, the scientist knows that which of the following occurred?

A. The luciferase gene mutated inside the cells.

B. The luciferase gene was transcribed and translated.

C. The luciferase gene destroyed the original genes of the cells.

D. The luciferase gene moved from the nucleus to the endoplasmic reticulum.

11. DNA replication and transcription are important processes in cells.

a. Identify the end products of both DNA replication and transcription. Be specific in your answer.

b. Explain the importance of each process in eukaryotic cells.

12. In a eukaryotic cell, which of the following processes directly involves DNA?

A. translation

B. cellular respiration

C. active transport of ions

D. replication of chromosomes

(Questions 13-15)

Sickle cell anemia is an autosomal recessive genetic disorder that affects thousands of people in the United States and millions worldwide. Sickle cell anemia commonly occurs in groups whose ancestors came from Africa, as well as South America, Cuba, Central America, Saudi Arabia, India, and the Mediterranean.

Sickle cell anemia is caused by a change in the hemoglobin protein in red blood cells. Sickle cell anemia results in paleness, fatigue, shortness of breath, and increased heart rate due to a deficiency in the oxygen-carrying component of the blood. When oxygen levels are low in an affected individual, the red blood cells become deformed into a curved, sickle shape. People with sickle cell anemia can experience swelling, pain, infection, and organ damage.

All individuals have two alleles for the gene that codes for the hemoglobin protein (Hb). Individuals with two Hb A alleles have normal, round red blood cells. Heterozygous individuals, with one Hb A allele and one Hb S allele, do not experience symptoms of the disease, but they may produce some sickle-shaped red blood cells. Individuals with two Hb S alleles have sickle cell anemia.

The diagrams to the right represent some of the steps in the formation of hemoglobin in two individuals,

Y and Z. In these diagrams, only a small part of the hemoglobin gene sequence is represented.

Individual Y has two Hb A alleles and therefore produces normal red blood cells. Individual Z has two Hb S alleles and therefore produces sickle-shaped red blood cells.

13. Which of the following statements best describes why the change in only one DNA base of the hemoglobin gene results in a different protein product of the gene?

A. The change prevents mRNA from being made.

B. The change alters the amino acid sequence of the protein.

C. The change causes the blood cells to divide in an uncontrolled way.

D. The change creates a second strand of mRNA for each RNA molecule.

14. Which of the following cell structures carries out the process represented by the arrows labeled “2” in the diagrams?

A. mitochondrion

B. nucleus

C. ribosome

D. vacuole

15. Which of the following statements best summarizes a change that is represented by the arrows labeled “3” in the diagrams?

A. A nucleus is formed in each cell.

B. Each cell divides to form two daughter cells.

C. A chain of amino acids is folded to form a protein in each cell.

D. Proteins are transported through the plasma membrane of each cell.

16. During DNA replication, the wrong nucleotide was inserted in the DNA sequence. Which of the following terms describes this situation?

A. mutation

B. regeneration

C. transcription

D. translation

17. A portion of one strand of a DNA molecule has the sequence shown below.

ACCTGAAGG

Assuming there are no mutations in this portion of the DNA, what is the corresponding sequence on the complementary DNA strand?

A. ACCTGAAGG

B. GTTCAGGAA

C. TGGACTTCC

D. UGGACUUCC

18. A hereditary muscular disease in horses causes abnormal opening and closing of the sodium ion channels in the muscle cells. Which of the following statements describes the most likely origin of this disease?

A. A virus evolved specifically to attach the muscle cells of the horse.

B. Motor neurons near some of the muscle cells degenerated over time.

C. High levels of sodium in the blood irreversibly damaged the ion channels.

D. A mutation occurred in the gene coding for the sodium ion channel protein.

ANSWERS

1. D

2. D

3. C

4. C 

5. C

6. D

7. B

8. B

9. B

10. B

11.

12. D

13. B

14. C

15. C

16. A

17. C

18. D