Genetics Exam 4: Questions

What is deamination? Provide an example.

- removal of an amine group from the cytosine base - the other bases are not readily deaminated

What region in eukaryotic genes contains the majority of regulatory elements?

-100 to -50

Most eukaryotic genes are collinear. T or F

-False

How many promoters are in an operon?

1

What stem-loop conformations favor attenuation in the trp operon?

1-2 and 3-4

What RNA modification is important for mRNA stability?

3' polyA tailing

The C-terminus of a polypeptide always contains

A carboxyl group

What are regulatory transcription factors regulated by (process)

Activators and repressors

If a point mutation increases the number of offspring an organism can produce, it would be called a ________ mutation.

Beneficial

Which subunit of the prokaryotic RNA polymerase carries out catalytic synthesis of RNA?

Beta subunit

What did the scientists Nirenberg and Matthaei study?

Cell -free translation system

Into which gene of the CRISPR-Cas system are fragments of bacteriophage DNA inserted?

Crispr

What are the four most common types of molecules to which ncRNAs bind?

DNA, RNA, proteins, and small molecules

List eukaryotic regulatory elements.

Enhancers Silencers Boundary elements Insulators

A repressor protein would enhance the ability of TFIID to bind to the TATA box of the promoter. T or F

False

Activator proteins bind to silencer sequences and repressor proteins bind to enhancer sequences. T or F

False

DNA methylation activates gene expression. T or F

False

DNA that contains actively transcribed genes would most likely contain chromatin in the closed configuration. T or F

False

Negative transcriptional regulation is conducted by activator proteins. T or F

False

Reverse mutations involve changing a wild-type allele to a mutant allele. T or F

False

The genetic code — the correspondence between codons and amino acids — is unique for each species of organism. T or F

False

The mutation frequency would be the same for all genes in a given culture. T or F

False

What's the difference between general and regulatory transcription factors?

General transcription factors are essential for any transcription for all genes while regulatory transcription factors regulate transcription of specific genes.

In eukaryotic organisms, where does the processing of the 45S rRNA into 5.8S, 18S, and 28S rRNA occur?

In the nucleolus

Where are the ribosomal subunits assembled?

In the nucleolus

The primary structure of a protein refers to

Its amino structure sequence

What is the equivalent of The CRISPR-Cas system in vertebrates?

Piwi-interacting RNA (piRNA)

What is the name of the transcription start site?

Promoter

Define ribozyme.

RNA molecules with catalytic function

In transcription, the closed complex consists of?

RNA polymerase Transcription factors -double-stranded DNA

What does Antisense RNA do?

Regulates translation

What level of protein structure is exemplified by α-helices and β-sheets?

Secondary structure

Provide the definition for the mutations below:

Silent: mutation that does not alter the amino acid sequenceNonsense: mutation that changes a codon to a stop codon Neutral: mutation that does not alter protein function Missense: mutation that does alter the amino acid sequence Frameshift: mutation that does alter the amino acid sequence

What general transcription factor is most often affected by regulatory transcription factors?

TFIID

What general transcription factor is a helicase?

TFIIH

In transcription, the RNA has a complementary sequence to what strand?

The template strand of DNA

Constitutive genes are those that have constant levels of expression. T or F

True

Nucleosome location may be changed by a process called ATP-dependent chromatin remodeling. T or F

True

Steroid hormones are an example of an effector which regulates regulatory transcription factor activity. T or F

True

The CpG islands upstream of housekeeping genes are unmethylated. T or F

True

The first person to suggest that a connection exists between the function of a gene and the production of an enzyme was Archibald Garrod. T or F

True

List the known stop codons?

UAA, UAG, and UGA

What are the components of combinatorial factors?

activators and repressors

What happens when histones experience Acetylation?

alters accessibility of chromatin and alters protein interactions

What did the scientists Beadle and Tatum study?

analysis of simple nutritional requirements

What type of activity do Ribozymes possess?

catalytic function

What did the scientists Khorana and colleagues study?

copolymers in a cell-free translation system

In prokaryotes, a holoenzyme is formed by what components?

core enzyme and sigma factor

The complete loss of either a guanine or adenine from DNA is an example of

depurination.

What can induce mutations?

environmental agents, mutagens, abnormalities in cellular processes

Genomic imprinting is a result of what process

epigenetic regulation

What is the function of TERC?

facilitates the binding of telomerase to the telomere and acts as a template for DNA replication

What human disease is associated with mutations in Drosha?

familial amyotrophic lateral sclerosis

Enzymes involved in metabolism are most likely regulated via ________.

feedback inhibition

The ncRNA HOTAIR recruits what type of proteins to target genes

histone-modifying complexes

Explain what Mello and Fire observed when the lowest amount of mex-3 probe staining occurred

it had been injected with double-stranded DNA

What are conditional mutations

mutations that affects the phenotype only under specific conditions

Abnormal levels of miRNAs are associated with nearly all forms of what type of human disease?

neurological disorders

What did the scientist Garrod study?

patients who had defects in their ability to metabolize certain compounds

What is the regulation of protein function called?

post-translational regulation

In the Jacob Monod merozygote experiment, what was indicated by the presence of a yellow color when b-ONPG was added?

presence of B-galactosidase

What are the steps in RNA interference?

pri-miRNA is made Cleaved to 70-nucleotide per-miRNA and exported Cut by dicer to 20-25 bp

CpG islands are associated with what process?

promoters

RNA polymerase I in eukaryotes produces which type of RNA?

rRNA (ribosomal RNA)

What is the function of this ncRNA?

regulate gene expression at the transcriptional and post-transcriptional level

Francis Crick proposed the adaptor hypothesis, and later the adaptor was discovered to be ________.

tRNA

Which molecule contains an anticodon?

tRNA

RF1 and RF2 are active during what stage?

termination

What is Anticipation?

the severity of the disease tends to worsen in future generations

How do regulatory transcription factors influence gene expression?

they influence the ability of RNA polymerase to begin transcription of a particular gene

What do Riboswitches regulate?

transcription, translation, RNA stability, splicing

Regulation of gene expression may occur at which of the following levels?

transcription, translation, and post-translation

What gene is responsible for attenuation of the trp operon?

trpL

What is reduction? During what process does it occur?

​​decrease in gene expression during translation