Genetics Mutations Classification

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What theory states that living creatures could arise without parents?

Biological Molecules Theory

Spontaneous Generation Theory (correct)

Germ Theory

Abiogenesis Theory

Which of the following is NOT one of Koch’s Postulates used to describe the role of microbes in diseases?

The suspected organism should be present in ALL cases of the disease and ABSENT from healthy animals (correct)

Cells from a pure culture of the suspected organism should CAUSE DISEASE in a healthy animal

The suspected organism should be grown in PURE CULTURE

The suspected organism should be REISOLATED (the same organism as before)

What is the main function of 16S rRNA in bacterial evolution?

To determine genetic relatedness and serve as a molecular clock (correct)

To initiate spontaneous generation of new bacteria

To cause disease in healthy animals

To preserve food and destroy crops

How did the theory of spontaneous generation get disproved?

By introducing microorganisms from the outside into sterile liquid Signup and view all the answers

Which type of molecules arise abiotically from simply reduced chemicals sparked by lighting?

Organic building blocks Signup and view all the answers

What is the most widely used molecular clock for bacterial evolution?

$16S rRNA$ Signup and view all the answers

What is the main impact of microorganisms on food availability?

It affects food availability both positively and negatively Signup and view all the answers

Which theory describes the idea that a specific type of microorganism causes a specific disease?

$Germ Theory$ Signup and view all the answers

Which type of molecules contain temporal information used as a molecular clock?

$16S rRNA$ Signup and view all the answers

What is the main reason behind the constant substitution rate in molecular clocks?

$16S rRNA$ has a slow evolving sequence divergence proportional to time Signup and view all the answers

Which type of mutation does not change the amino acid sequence?

Silent mutation Signup and view all the answers

What is the enzyme that promotes transposition in the simplest transposons?

Transposase Signup and view all the answers

What is the function of the Ames test?

To test the strength of mutagens Signup and view all the answers

Which repair mechanism corrects mismatches missed by proofreading?

Methyl mismatch repair Signup and view all the answers

What happens when extensive DNA damage induces SOS response?

RecA inactivates LexA Signup and view all the answers

What type of repair recognizes and repairs bases that mostly do not distort DNA structure?

Base-excision repair Signup and view all the answers

What is a characteristic of transversion mutations?

Change from purine to pyrimidine or vice versa Signup and view all the answers

What is the term used for the addition of one or more bases in DNA?

Insertion Signup and view all the answers

What is a characteristic of silent mutations?

Does not change the amino acid sequence Signup and view all the answers

What is a characteristic of point mutations?

Changes in a single base Signup and view all the answers

What distinguishes prokaryotic cells from eukaryotic cells in terms of DNA location?

Prokaryotic DNA is not bounded by a membrane Signup and view all the answers

Which bacterial cell shape is characterized by a helical structure?

Vibrios Signup and view all the answers

What is the main difference between the envelopes of Gram-positive and Gram-negative bacteria?

Gram-negative bacteria have an outer membrane Signup and view all the answers

What step of the Gram stain procedure removes the stain from Gram-negative but not from Gram-positive cells?

Wash with ethanol Signup and view all the answers

How can chemical gradients across membranes be used to drive cellular processes?

By storing energy in the gradient Signup and view all the answers

What is the primary characteristic of active transport?

Direct use of energy to move molecules against the gradient Signup and view all the answers

Which transport system combines active energy use with facilitated diffusion?

PTS transport Signup and view all the answers

What distinguishes Sec-dependent secretion systems in bacteria?

Requires ATP hydrolysis to move proteins out Signup and view all the answers

What type of transport system escorts specific substrate to transporter?

'ABC' transporters Signup and view all the answers

What happens to the signal peptide during the secretion via Sec-dependent secreted proteins?

The signal peptide is cleaved by the signal peptidase enzyme during secretion Signup and view all the answers

What is the main advantage of using ribosomal DNA for evolutionary studies?

It encodes components of the transcription and translation apparatus Signup and view all the answers

According to the endosymbiont theory, how did mitochondria and chloroplasts originate?

They were bacteria that were infected or eaten by other species and ended up living symbiotically inside Signup and view all the answers

What is the role of the restriction/modification system in bacterial cells?

To cut foreign DNA using restriction endonucleases and protect native DNA by methylation Signup and view all the answers

Which enzyme is responsible for removing RNA primers and filling the gaps in the lagging DNA strand during bacterial chromosomal replication?

DNA polymerase I Signup and view all the answers

What is the function of sigma factors in transcription?

They recognize promoters and guide the core enzyme to initiate transcription Signup and view all the answers

What is the general role of repressors in gene expression regulation?

They bind to regulatory sequences and prevent transcription of target genes Signup and view all the answers

What are open reading frames (ORFs) in the context of molecular genetics?

Triplets of nucleotides that represent amino acids in translation Signup and view all the answers

In Rho-independent transcriptional termination, what causes the RNA polymerase to pause and terminate transcription?

Formation of stem-loop structure due to GC-rich sequence Signup and view all the answers

How does prokaryotic translation differ from eukaryotic translation?

Prokaryotic translation uses different initiation and release factors compared to eukaryotic translation Signup and view all the answers

What is the significance of the Shine-Dalgarno sequence in translation?

It allows binding of mRNA to the ribosome's small subunit for translation initiation Signup and view all the answers