Mastering Biology CH 17 Homework Flashcards

Questions and Answers

Which of the following terms associated with transcription describe regions of nucleic acid?

Promoter

Terminator

Gene

All of the above (correct)

Place the events in the transcription of a gene in their proper order from left (first event) to right (last event).

RNA polymerase binds promoter = First event RNA polymerase transcribes gene = Middle event RNA polymerase reaches terminator = Second to last event RNA polymerase exits gene, RNA is released = Last event

In the diagram below, the gray unit represents _____

RNA polymerase

In the diagram below, the green unit represents _____

the promoter Signup and view all the answers

In the diagram below, the two blue strands represent _____

DNA Signup and view all the answers

Which of these correctly illustrates the pairing of DNA and RNA nucleotides?

CAAUGC Signup and view all the answers

The direction of synthesis of an RNA transcript is ____.

5' --> 3' Signup and view all the answers

What is the corresponding sequence of bases in the RNA that is produced from the DNA sequence given?

UGAGCC Signup and view all the answers

What ultimately determines which DNA strand serves as the template strand?

the base sequence of the gene's promoter Signup and view all the answers

Which three statements correctly describe the processing that takes place before a mature mRNA exits the nucleus?

A cap consisting of a modified guanine nucleotide is added to the 5' end of the pre-mRNA. Signup and view all the answers

What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA?

transcription Signup and view all the answers

What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?

translation Signup and view all the answers

What name is given to the process in which pre-mRNA is edited into mRNA?

RNA processing Signup and view all the answers

Polypeptides are assembled from _____.

amino acids Signup and view all the answers

What is the process called that converts the genetic information stored in DNA to an RNA copy?

transcription Signup and view all the answers

Which of the following does DNA not store information to synthesize?

organelles Signup and view all the answers

What is a promoter?

A site in DNA that recruits the RNA polymerase Signup and view all the answers

What determines which base is to be added to an RNA strand during transcription?

Base pairing between the DNA template strand and the RNA nucleotides Signup and view all the answers

Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand?

complementary Signup and view all the answers

What happens to RNA polymerase II after it has completed transcription of a gene?

It is free to bind to another promoter and begin transcription. Signup and view all the answers

During RNA processing, a(n) _____ is added to the 5' end of the RNA.

modified guanine nucleotide Signup and view all the answers

During RNA processing, a(n) _____ is added to the 3' end of the RNA.

a long string of adenine nucleotides Signup and view all the answers

Spliceosomes are composed of _____.

small RNAs and protein Signup and view all the answers

The RNA segments joined to one another by spliceosomes are ____.

exons Signup and view all the answers

Translation occurs in the ____.

cytoplasm Signup and view all the answers

Use the table to sort the following ten codons into one of the three bins, according to whether they code for a start codon, an in-sequence amino acid, or a stop codon.

UAA Signup and view all the answers

What amino acid sequence does the following mRNA nucleotide sequence specify: 5′−AUGGCAAGAAAA−3′?

Met-Ala-Arg-Lys Signup and view all the answers

What amino acid sequence does the following DNA nucleotide sequence specify: 3′−TACAGAACGGTA−5′?

Met-Ser-Cys-His Signup and view all the answers

Which of the following mutations would likely be most dangerous to a cell?

deletion of one nucleotide Signup and view all the answers

What type of mutation could swapping an A for a T cause?

It could cause a silent, missense, or nonsense mutation. Signup and view all the answers

Why is a frameshift missense mutation more likely to have a severe effect on phenotype than a nucleotide-pair substitution missense mutation?

A substitution missense affects only one codon, but a frameshift missense affects all codons downstream of the frameshift. Signup and view all the answers

Study Notes

Transcription Basics

Transcription: The process of synthesizing RNA from a DNA template.
Key components: Promoter (site where RNA polymerase binds), terminator (signals the end of transcription), gene (the sequence being transcribed).
Direction of synthesis: RNA is synthesized in the 5' to 3' direction.

Stages of Transcription

RNA polymerase activity:
- Binds to the promoter, initiating transcription.
- Transcribes the gene as it moves along the DNA.
- Reaches the terminator, signaling the end of transcription.
- Exits, releasing the RNA molecule.

RNA and DNA Relationship

RNA is complementary to the DNA template strand, replacing thymine (T) with uracil (U).
Base pairing in RNA: GTTACG pairs with CAAUGC during transcription.

Eukaryotic RNA Processing

Pre-mRNA undergoes processing to become mature mRNA:
- Addition of a modified guanine cap at the 5' end.
- Addition of a poly-A tail (50-250 adenine nucleotides) at the 3' end.
- Splicing out of introns by spliceosomes, leaving exons.

Codons and Translation

Codons: Nucleotide triplets that specify amino acids.
Start codon: AUG (methionine), initiation of translation.
Stop codons: UAA, UAG, UGA, terminate translation.
Example amino acid sequences correspond to mRNA sequences:
- 5′-AUGGCAAGAAAA-3′ translates to Met-Ala-Arg-Lys.

Mutation Types

Point mutations can lead to:
- Silent mutations: No change in amino acid sequence.
- Missense mutations: Result in a different amino acid.
- Nonsense mutations: Introduce a premature stop codon.
Frameshift mutations: Caused by insertions or deletions that disrupt the reading frame.

Protein Structure

Levels of protein structure:
- Primary: Amino acid sequence.
- Secondary: Alpha helices and beta pleated sheets from hydrogen bonding.
- Tertiary: Overall shape due to interactions between R groups.
- Quaternary: Aggregation of multiple polypeptide chains.

Role of RNA Types

mRNA: Carries genetic information from DNA to ribosome.
tRNA: Brings amino acids to the ribosome during translation; contains an anticodon for pairing with mRNA.
rRNA: Major component of ribosomes, aiding in translation.

Cellular Location of Protein Synthesis

Translation takes place in the cytoplasm.
Eukaryotic protein synthesis: Begins in the ribosome after processing mRNA in the nucleus.

Genetic Code Characteristics

Genetic code consists of codons which dictate amino acid sequence.
Different codon combinations yield different amino acids, with redundancy in the genetic code.

Disease Association

Mutations in the CFTR gene lead to cystic fibrosis, with various mutations (like delta F508) affecting protein function.

Risk of Mutations

Deletion of a single nucleotide is often most detrimental due to potential frameshifts.

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Description

Test your understanding of transcription with these flashcards from Chapter 17 of Mastering Biology. Learn key terms associated with nucleic acids and the order of events during gene transcription. Perfect for reinforcing your comprehension of essential biological processes.