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WorksheetsExam 3
Total questions: 106
Worksheet time: 54mins
Which statement best distinguishes polypeptides from proteins according to the material?
Polypeptides are units of function; proteins are units of structure
Proteins are composed of one or more polypeptides and are units of function
Proteins are single polypeptides and serve no function
Polypeptides are composed of multiple proteins and are units of function
In eukaryotes, what happens to mRNA before it exits the nucleus?
It is translated by cytoplasmic ribosomes
It is degraded by nucleases
It is modified, including capping, splicing, and addition of a poly A tail
It is exported without any changes
Which components initiate transcription in prokaryotes versus eukaryotes, respectively?
RNA polymerase alone; sigma factor with RNA polymerase
Sigma factor with RNA polymerase; five transcription factors with RNA polymerase
Five transcription factors with RNA polymerase; sigma factor with RNA polymerase
Transcription factors only; sigma factor only
During transcription, synthesis proceeds along DNA in which orientation, and how is termination defined?
Synthesized 3' to 5'; a promoter defines where it ends
Synthesized 5' to 3'; a terminator specifies where it ends
Synthesized bidirectionally; termination is random
Synthesized 5' to 3'; termination occurs only at promoters
Which set lists all core requirements for translation as described?
mRNA, DNA polymerase, ribosomes, release factors
mRNA, charged tRNA, ribosomes, and translation factors
pre-mRNA, spliceosome, ribosomes, helicase
rRNA, sigma factor, ribosomes, transcription factors
What is the correct description of tRNA structure and function?
Linear molecule with codon and amino acid at 5' end
Cloverleaf molecule with an amino acid attachment site at the 3' end and an anticodon
Double-stranded molecule that binds the promoter
Circular RNA that carries peptide chains
Which sequence correctly describes early events of translation according to the notes?
Initiation: initiator tRNA enters the A site; Elongation: amino acids are added at the P site
Initiation: mRNA assembles with the ribosome and initiator tRNA enters the P site; Elongation: charged tRNA delivers amino acids to the A site
Initiation: ribosome forms after stop codon; Elongation: tRNA exits through the A site
Initiation: transcription factors bind mRNA; Elongation: DNA is replicated
Which statement best defines a mutation in genetics?
A random change in protein folding
A heritable change in the genetic material
A temporary change in gene expression
A deletion of an entire chromosome
Point mutations affect a single base pair and can be classified as which of the following?
Silent, missense, nonsense, and frameshift
Deletion, duplication, inversion, and translocation
Lytic, lysogenic, temperate, and latent
Promoter, enhancer, operator, and terminator
Which type of mutation can be passed to offspring?
Somatic mutations
Germ-line mutations
Silent mutations only
Induced mutations only
Spontaneous mutations are primarily the result of which cause?
Exposure to chemical mutagens
Abnormalities in biological functions
UV radiation
Errors introduced by the Ames test
What does the Ames test determine?
Whether DNA damage can be repaired by NER
Whether an agent is a mutagen
Whether a mutation is germ-line or somatic
Whether mutations are random events
Nucleotide excision repair (NER) primarily performs which function?
Adds nucleotides to the 3' end of RNA primers
Recognizes various types of DNA damage and excises the damaged region
Replicates the entire genome during S phase
Converts thymine to uracil in DNA
A defect in the NER system most directly explains which human condition mentioned?
Sickle-cell anemia
Xeroderma pigmentosum
Cystic fibrosis
Huntington's disease
Which statement best describes viruses according to the material?
Viruses are living cells that reproduce independently
Viruses are non-living particles that use living cells to replicate
Viruses are proteins that self-replicate without hosts
Viruses are organelles within eukaryotic cells
Which sequence correctly lists the general steps of a typical viral reproductive cycle?
Attachment, integration, synthesis of components, assembly, release
Penetration, mitosis, transcription, translation, budding
Recognition, endocytosis, replication, cytokinesis, fusion
Adsorption, binary fission, transcription, packaging, exocytosis
Some bacteriophages can follow two reproductive cycles. Which pair names them?
Binary and budding
Mitosis and meiosis
Lytic and lysogenic
Assembly and release
What distinguishes emerging viruses as highlighted in the material?
They only infect bacteria
They cause significant loss of life
They cannot be transmitted between hosts
They are always harmless
Which infectious agent is defined as an RNA molecule that can infect plant cells?
Prion
Viroid
Bacteriophage
Retrotransposon
Prions are described as infectious proteins that induce abnormal folding of proteins and cause fatal neurodegenerative diseases. Based on this description, which statement is consistent with the material?
Prions are nucleic acids that integrate into genomes
Prions require a DNA intermediate to replicate
Prions act at the protein level and are not nucleic acids
Prions are known to cause disease in humans according to the note
A virus shows a narrow host range, infecting only a few species. Which concept from the material does this illustrate?
Viruses vary in host range
Viruses are living cells
Prions infect plant cells
Viroids cause significant loss of life
During the lysogenic cycle mentioned for some bacteriophages, which process is implied by the term integration within the reproductive steps?
Incorporation of viral nucleic acid into the host genome
Immediate lysis of the host cell
Assembly of viral capsids
Release of mature virions from the cell
You are asked to name at least one emerging virus that impacts humans. Which option appropriately satisfies this instruction based on the material’s prompt?
Zika virus
Xeroderma pigmentosum
Viroid
siRNA
Which statement best describes gene regulation in organisms?
Most genes are expressed at constant levels with no regulation
Most genes are regulated, while constitutive genes are usually expressed at constant levels
Gene regulation only occurs in prokaryotes
Gene regulation always increases the amount of DNA in the genome
What is a primary role of gene regulation in multicellular organisms?
Increasing mutation rates
Allowing for differentiation of cells
Reducing transcription factors
Eliminating enhancers and silencers
Alternative splicing is typically observed in which type of cells, and what is its consequence?
Prokaryotic cells; decreases proteome diversity
Eukaryotic cells; means a single gene can code for more than one polypeptide
Prokaryotic cells; increases the amount of DNA
Eukaryotic cells; removes introns but does not affect protein diversity
Which advantage is directly associated with alternative splicing?
It increases the diversity of the proteome without increasing the amount of DNA
It reduces the need for transcription factors
It eliminates post-transcriptional regulation
It ensures each gene codes for only one polypeptide
MicroRNAs primarily regulate gene expression by which mechanism?
Enhancing translation through ribosome recruitment
Degrading mRNA or blocking translation by matching with complementary strands
Increasing DNA methylation
Activating enhancers to boost transcription
Which statement correctly differentiates microRNA from siRNA based on the material?
MicroRNA forms a complex with mRNA and slices it; siRNA blocks translation
Both microRNA and siRNA only act in the nucleus
MicroRNA matches complementary strands to degrade or block translation; siRNA forms a complex with mRNA and slices it
siRNA increases proteome diversity through alternative splicing
Which regulatory components are involved in controlling gene expression, as listed in the material?
Only repressors and activators
Transcription factors, small effector molecules, regulatory elements, enhancers, silencers, GTFs, chromatin changes, DNA methylation, histone modifications
Only DNA methylation and histone modifications
Only GTFs and enhancers
What is the main function of RNA-binding proteins in gene regulation according to the material?
Regulating translation
Promoting DNA replication
Causing chromatin changes
Editing DNA sequences
In cell signaling, what process is emphasized as occurring between cells?
Gene cloning
Signal transduction communication
DNA microarray profiling
Alternative splicing
What is a key feature of homeobox genes as presented?
They control groups of genes and are important for body plan in early stages
They only function in adult tissues to repair DNA
They exclusively regulate microRNA processing
They act as restriction enzymes in development
Which technique allows researchers to see what genes are being transcribed in various cells?
CRISPR-Cas
DNA microarray
Gene cloning in mice
Signal transduction
Which statement best defines a genetically modified organism (GMO)?
An organism with genes introduced naturally through reproduction
An organism that has genes artificially introduced
An organism with no genetic changes
An organism with only epigenetic modifications
Transgenic organisms are specifically characterized by which feature?
Genes removed to reduce expression
Genes introduced from another organism
Chromosomes duplicated within the same cell
Proteins chemically modified post-translation
What role do plasmids most commonly play in genetic engineering according to the material?
They act as enzymes that cut DNA at specific sites
They function as vectors to introduce new genes into an organism
They silence gene expression through RNA interference
They map genomes by sequencing entire chromosomes
Restriction enzymes are used to perform which key procedure?
Ligate DNA fragments together
Cut DNA at a specific sequence
Amplify DNA across regions of interest
Insert DNA into host genomes randomly
Compared with restriction enzymes, the CRISPR-CAS system is described as enabling what advantage?
A more targeted approach to genome editing
Higher rates of random mutation
Exclusive use in plants only
Mapping entire genomes
Which medical application is explicitly linked to biotechnology in the material?
Production of human insulin
Development of antibiotics
Creation of vaccines from attenuated viruses
Gene silencing for epigenetic therapy
According to the text, genetically modified food crops can achieve all of the following EXCEPT:
Produce higher yields
Resist pests and drought
Increase salt tolerance
Eliminate the need for photosynthesis
Human gene therapy is described as being used to accomplish which goal?
Enhance athletic performance
Treat genetic diseases
Determine population allele frequencies
Clone human tissues for transplants
Genetic material is noted as beneficial in forensics primarily for which purposes?
Estimating mutation rates
Solving crime, identifying remains, determining paternity
Engineering salt-tolerant crops
Producing therapeutic proteins
What is a stated benefit of genome mapping by researchers?
It reduces ethical concerns about biotechnology
It can help diagnose conditions
It replaces CRISPR-CAS techniques
It ensures all GMOs are safe
Which statement best captures an ethical consideration mentioned in the material regarding biotechnology and genetic engineering?
There are no ethical questions associated with genome editing
Ethical questions arise in the use of these technologies
Ethical questions only apply to crop engineering, not medicine
Ethical concerns are limited to paternity testing
Which statement best distinguishes natural selection from artificial selection?
Natural selection is driven by human preferences, while artificial selection is driven by environmental pressures.
Natural selection is driven by environmental pressures, while artificial selection is driven by human preferences.
Both natural and artificial selection are driven solely by random genetic drift.
Artificial selection operates only on populations, while natural selection operates only on individuals.
Which source of genetic variation directly results from the random separation of homologous chromosomes during meiosis?
Mutation
Independent assortment
Crossing over
Random fusion of gametes
In the context of evolution, what level actually changes over time?
Individuals
Populations
Organs
Ecosystems always change without genetic basis
Which mechanism of evolution is most closely associated with a sharp reduction in population size due to a catastrophe, leading to reduced genetic diversity?
Founder effect
Bottleneck effect
Gene flow
Sexual selection
Directional selection primarily has which effect on a population’s trait distribution?
Splits the population into two extremes
Favors the intermediate phenotype
Shifts the entire population toward one extreme
Eliminates variation entirely
Which evidence type would be used to support evolution by comparing structures that share common ancestry but may have different functions?
Vestigial structures
Homologous structures
Analogous structures
Fossilized pollen only
Antibiotic resistance in pathogenic bacteria illustrates which evolutionary mechanism most directly?
Genetic drift
Natural selection
Founder effect
Gene flow
Plasmids are
small circular DNA that is often found in bacteria
the entire bacterial chromosomes
linear chromosomes found in humans
Extra chromosomes that are the result of non-disjunction events
True or false: Broccoli and cauliflower are the same species of plant
true
false
The CRISPR-Cas system is
A completely human generated system of cutting DNA at specific base pairs
An immune system found in bacteria and archaea
Was discovered by Watson and Crick
None are true
True or False: Human gene therapy can be used to treat some genetic diseases
true
false
true or false:
Translation of mRNA occurs in the cytosol for both prokaryotic and eukaryotic cells.
true
false
true or false:
The segments that are removed during the splicing of pre-mRNA are called exons
true
false
The Ames Test
Provides a way to determine if an agent is a possible mutagen
Provides a way to determine if any type of cell has experienced a mutation
Allows researchers to experimentally disrupt gene activity by causing a mutation in a specific gene
Provides a way to repair mutations in bacterial cells
A mutation that changes a proline codon (CCG) to a threonine codon (ACG) is an example of a point mutation.
true
false
You likely have some mutated DNA in some of your cells right now
true
false
Which of the following is NOT required for translation
tRNA
ribosomes
dsRNA
mRNA
Which of the following is true regarding a silent mutation
It would not cause any changes to the amino acid sequence in the polypeptide
It is likely advantageous to the organism
It is likely deleterious to the organism
One cannot determine if the change would be advantageous or deleterious to the organism from the information provided
A mutation changes a proline codon (CCG) to a threonine codon (ACG). This is an example of
Nonsense mutation
Silent mutation
Frameshift mutation
Missense Mutation
A somatic cell mutation has occurred that has caused a child to develop a lack of pigment in one area, the result is a white patch of hair on their head. Which of the following is false regarding this mutation:
This would not be considered a germ-line mutation
The child would be considered a mosaic in this case.
This child would likely pass this trait to their offspring
This child would not pass this trait to their offspring
true or false:
A nonsense mutation changes the reading frame and would likely create a vastly different polypeptide
true
false
HIV, a retrovirus, has a high rate of mutation because:
Antibodies produced by host cells mutate the viral genome when infection occurs
The genome of HIV is less stable than other viral genomes
Reverse transcriptase lacks a proofreading function, so errors occur more often
All of the answers are correct as they all impact the rate of mutation in HIV
Which of the following is not a stage where gene regulation usually occurs in bacteria?
Translation
Post Translation
RNA Modification
Transcription
In bacteria, the segment of DNA that contains multiple genes under control of a single promoter is called ______. The mRNA produced from this unit is referred to as ____mRNA
Operator, polycistronic
Operator, polycistronic
Template, structural
Operon, polycistronic
true or false: Prion diseases are always fatal
true
false
We looked at some examples of human cells: pancreas cells, white blood cells, and nerve cells. Assume all the cells came from the same individual, which of the following is/are different between these cells?
Neither the genome nor the proteome
The proteome
Both the genome and the proteome
The genome
true or false: There is scientific consensus that viruses are living organisms.
true
false
true or false: The mechanism that causes prion disease is well understood
true
false
What are the stages of the viral reproductive cycle
Synthesis of components, attachment, meiosis, gamete fusion
Attachment, system takeover, release, assembly
Attachment, integration, synthesis of components, assembly, and release
None of the answers are correct, viruses do not have a reproductive cycle
Gene expression is
Proteins that bind to regulatory sequences
Proteins that bind to regulatory sequences
The process by which information in a gene is made into a functional product
The ability of cells to control the expression of their genes
true or false: prions are solely made of rna
true
false
true or false: evolution is forward thinking
true
false
Explain how prion diseases are typically transmitted.
Through respiratory droplets
By consuming infected tissue
Through skin contact
By genetic inheritance
Why do antibiotics destroy bacterial cells but have no effect on viruses?
Viruses are made up of organic molecules that are too small to be targeted by antibiotics.
Viruses are not alive and do not carry out the life functions that are stopped by antibiotics
Viruses do not possess the protein coat that is targeted by all antibiotics
Which of the following is not typically used by scientists to define a species?
Morphological Traits
Ability to interbreed
Blood type patterns
Evoluntionary Relationships
Prezygotic barriers prevent mating or fertilization between species by all of the following except:
Temporal Isolation
Behavioral Isolation
Hybrid Sterility
Mechanical isolation
Which of the following is a postzygotic barrier?
Habitat Isolation
Gametic Isolation
Temporal Isolation
Reduced Hybrid Fertility
Allopatric speciation occurs when:
A population becomes geographically separated
Species evolve within the same geographic area
Two species share identical habitats
A species becomes extinct
Sympatric speciation often results from:
Physical barriers
polyploidy and sexual selection
continental drift
mass extinction
Adaptive radiation refers to:
the loss of species diversity after an extinction
a single species evolving into many different species
the fusion of hybrid species
gradual gene flow between population
Macroevolution is best described as:
genetic change within a population
evolution above the species level
mutation within a single organism
natural selection in a single generation
Which of the following events has most contributed to macroevolutionary change?
hybridization
mass extinctions
behavioral isolation
gametic incompatibility
Evo-devo helps scientists understand:
The ecological niche of a species
How developmental genes affect evolutionary relationships
how organisms migrate
the fossilization process
When scientists say evolution is not forward-thinking, they mean:
evolution has a specific goal
organisms evolve traits in anticipation of needs
existing structures can take on new functions
species stop evolving stop adapting
convergent evolution produces
Homologous structures in related species
Analogous structures in unrelated species
identical DNA sequences
the same ancestral species
Analogous structures in unrelated species
common ancestry
similar environmental pressures only
random change
no evolutionary relationship
phylogenetic tree represents:
proven evolutionary fact
a hypothesis of evolutionary relationships
a map of population density
a record of behavioral traits
Human-altered systems can lead to:
stabilization of ecosystems
no evolutionary changes
rapid changes in organisms
elimination of natural selection
In a particular bird species, individuals with average-sized wings are more likely to survive severe storms that the birds in the population with short or long wings. This would likely result in:
Directional selection
Disruptive selection
Stabilizing selection
None of these are true
true or false: taxonomy is the branch of biology concerned with identifying, naming, and classifying species
true
false
An example of a vestigial structure would be
the post anal tail seen on chicken and human embryos
the forelimb structures of humans, cats, whales, and bats
the variation in tortoise shells seen across the islands of the galapagos
the blue feet of the blue footed booby
Constitutive or housekeeping genes have constant levels of expression
true
false
When looking at gene regulation, a repressor is a regulatory transcription factor that increases the rate of transcription
true
false
Human gene therapy can be used to treat some genetic diseases
true
false
MicroRNAs and small interfering RNA (siRNA) are molecules that attach to mRNA and increase the rate of translation
true
false
In gel electrophoresis samples of fragmented DNA are placed into wells and are subjected to ______ that causes the fragments to move. The distance the fragments move is in response to the fragment's ______
Chemical gradient, polarity
Electric current, charge
Chemical gradient, charge
Electric current, size
Plasmids are
The entire bacterial chromosome
Extra chromosomes that are the result of non-disjunction events
Linear chromosomes found in humans
Small circular DNA that is often found in bacteria
The CRISPR-Cas system is
A completely human generated system of cutting DNA at specific base pairs
An immune system found in bacteria and archaea
The feel of the cool fall air on your face
Discovered by Watson and Crick
Which one of the following is not associated with an increased risk of cancer?
Smoking or using tobacco products
Eating a diet high in fiber and low in fat
Alcohol consumption
High exposure to UV
A proto-oncogene is
The ancestral gene that a current gene evolved from
A gene that is currently causing cancer cells to grow
A gene that codes for protein that inhibits call growth or cellular division
A normal gene that has the potential to become a gene that can cause cancer
