Biology: Cell Division, Genetics, Evolution, and Microorganisms

How is binary fission similar to mitosis with cytokinesis?

Both involve replication of DNA and separation of DNA equally into two daughter cells.

If an E. coli strain has 50 loop domains, how many total base pairs might this bacteria have in its chromosome?

200,000-450,000 base pairs.

What mechanism is used by a bacterial cell to fit its DNA into the nucleoid region?

The formation of loop domains and supercoiling by topoisomerases.

What is an episome?

A plasmid that can exist either autonomously in the cytoplasm or as part of a chromosome.

What role do bacterial plasmids play?

They can provide genes that allow the bacteria to grow and thrive in the presence of potential toxins.

How long will it take for Bacterial strain A, dividing every 30 minutes, to produce 4 billion cells from a single cell?

16 hours.

What happened to Bacterium BB that can now degrade toluene and is pathogenic?

Bacterium BB acquired degradative and virulence plasmids by horizontal gene transfer.

What is true about different strains of a bacterial species?

They reproduce asexually, can participate in conjugation and transformation, and may be susceptible to different antibiotics.

What is required for a bacterial cell to transfer portions of its chromosome to another cell by conjugation?

An F factor.

In conjugation, what does the donor cell make to facilitate DNA transfer?

A sex pilus.

Order the events of bacterial conjugation: 1 - DNA replication, 2 - enzyme joins F factor DNA ends, 3 - sex pilus shortens, 4 - DNA transfer, 5 - enzyme cuts F factor DNA.

3, 5, 1, 2, 4.

What can be done to make E. coli competent for DNA uptake?

take up DNA from the environment.

What characterizes a competent bacterial cell?

It is able to take up DNA from the environment.

Why can resistant strains of bacteria evolve quickly after the introduction of antibiotics?

Bacteria can transfer plasmids containing resistance genes via conjugation.

What is a virus?

A particle that consists of nucleic acids surrounded by protein and requires a host organism to replicate.

Which component of a virus is not encoded by its own genome?

Lipid bilayer of viral envelope.

What is accurate about the envelope of the influenza virus?

The envelope is obtained from the host cell when the virus buds from the plasma membrane.

What might cause bacteria to die after enriching media with amino acids and carbohydrates?

environmental conditions may trigger this virus to switch to the lytic, the active or infective part of the reproductive cycle, which can destroy the cell.

What could cause a pro- strain of bacteria to develop the ability to produce proline?

Addition of the pro+ gene via transformation.

What is the process of removing the pro- gene during excision?

The removal of the pro- gene is part of genetic modification techniques.

How can a pro- gene be corrected?

By reverse transcriptase.

What method can be used to add a pro+ gene?

Transduction.

What is a possible consequence of mutation during phage integration?

Transduction, or transfer of genetic material via a virus, is a possible method of transfer of the pro+ gene that does not require other bacterial strains

Why do persons infected with HIV often die of opportunistic diseases?

Because HIV destroys T cells.

What does the term evolution refer to?

Heritable changes in characteristics of a population from one generation to the next.

What is microevolution?

Evolution viewed on a small scale, relating to changes in a single gene or allele frequency in a population over time.

What hypothesis did Peter and Rosemary Grant propose regarding finches on the Galápagos Islands?

Dry conditions produce larger seeds, resulting in larger beaks in succeeding generations of finches.

What is true of a fossil classified as a 'transitional form'?

It has some traits of its ancestors and some traits of its descendants.

What unique trait was found in Titaalik roseae that was not present in its ancestral form?

Primitive wrists and fingers.

Which scenario best illustrates natural selection?

A population of mosquitoes develops resistance to a pesticide.

What is selective breeding?

Programs designed to modify traits in domesticated species.

What is convergent evolution?

Similarity in evolutionarily unrelated groups due to adaptation to similar environments.

What explains the presence of two morphs of swallowtail tiger butterflies?

The swallowtail tiger butterfly has more than one allele for the gene that determines color.

What are vestigial structures?

Remains of structures that were functional in ancestral forms but are reduced or non-functional in descendants.

What structures in humans show developmental homology with other chordates?

Gill ridges and a bony tail.

What does greater sequence similarity in amino acid sequences indicate?

Greater sequence similarity within closely related groups.

What is the best explanation for differences in genetic coding between E. coli and Clostridium acetylbutylicum?

After diverging, the genes accumulated random mutations resulting in similar but not identical sequences.

If two genes are homologous, what can be said about them?

They are derived from the same ancestral gene.

What is a gene pool?

All the genes in a population.

What is a single-nucleotide polymorphism?

The smallest type of genetic change that can occur within a given gene.

What does the Hardy-Weinberg equation represent for heterozygotes?

The genotype frequency of heterozygotes is represented by 2pq.

What event is likely to lead to directional selection?

A population's main food source changes.

What are the two principal factors that lead to microevolution?

Mutation and natural selection.

What is the process called that results in the formation of new species?

Macroevolution

What is the term for the splitting or diverging of a population into two or more species?

Cladogenesis

What is the difference between allopatric and sympatric speciation?

Allopatric speciation occurs due to geographical isolation, while sympatric speciation occurs without physical barriers.

What is a disadvantage of using DNA or RNA sequences to identify species?

There is no rule for determining the number of sequence differences needed for a new species.

What is true about natural selection?

Natural selection is a way for evolution to occur and does not act on individuals.

What are Hox gene complexes responsible for in mammals?

They determine cell fate along the anteroposterior axis.

What criteria can be used to identify species?

Ecological factors, evolutionary relationships, molecular similarity, and the ability to interbreed.

What is the term for when two populations of the same species are geographically restricted but display different traits?

Subspecies

What is the phenomenon called when one region of the body grows faster than another among different species?

Heterochrony

What is the term for a new species that arises from the interbreeding of two other species with different chromosome numbers?

Allotetraploid

What type of isolation occurs when male and female genitalia do not fit properly?

Mechanical isolation

What is the term for the process of genetic change in a population due to geographical isolation?

Allopatric speciation

What is the relationship between beak depth and song characteristics in Darwin's finches?

Beak depth was correlated with song duration and complexity.

What is the term for the ability of species that do not interbreed in nature to breed successfully in captivity?

Hybridization

What is the term for the evolutionary mechanisms that include genetic mutations and migration?

Evolutionary mechanisms

What is the term for the ecological variation that can lead to sexual selection?

Parapatric speciation

What is the term for the phenomenon where a small group of individuals colonizes a new area?

Founder effect

What is true about the expression of BMP4 and Gremlin in chicken and duck feet?

BMP4 is expressed similarly in both, while Gremlin is not expressed between chicken digits.

What is the term for the evolutionary change that occurs within a population over time?

Microevolution

What is the role of polyploidy in speciation?

Polyploidy can lead to the formation of new species that can only reproduce with each other.

What is the significance of the Isthmus of Panama in evolutionary biology?

It caused allopatric speciation by splitting an ancestral fish population into two distinct species.

What is the term for the reproductive isolation that occurs due to differences in mating behaviors?

Behavioral isolation

What is the term for the gradual change in a species over time?

Anagenesis

What might lead to the occurrence of a hybrid zone after two goat populations are separated by a glacier?

Reproductive isolation is incomplete.

What is the science of describing, naming, and classifying organisms called?

Taxonomy.

What is the study of biological diversity and evolutionary relationships among organisms?

Systematics.

Which organism is NOT classified in the Domain Eukarya?

Salmonella enterica (bacteria that causes food poisoning).

Which taxonomic group is the broadest?

Kingdom.

What naming system did Linnaeus create for organisms, and what does 'miliarius' designate in Sistrurus miliarius?

Binomial nomenclature; specific epithet.

What theory suggests that most genetic variation in populations is not subject to natural selection?

The neutral theory of evolution.

What is the genus name for the golden crayfish, Orconectes luteus?

Orconectes.

Can a phylogenetic tree's structure be revised as new information becomes available?

True.

What type of evolution does cladogenesis represent?

The branching of a lineage into two or more distinct species.

What is it called when a single large population evolves into a new species over generations?

Anagenesis.

What term refers to similarities among species due to a common ancestor?

Homology.

Can two species in the same clade have more than one common ancestor?

Yes, they can have older common ancestors in their evolutionary history.

What type of traits are used to create a cladogram for the horse family?

Morphological traits.

What is a branching point in a phylogenetic tree called, and what does it illustrate?

Node; it illustrates that cladogenesis has occurred.

In a cladogram, which animals make up the outgroup if the ingroup consists of salmon, lizard, and rabbit?

Lancelet and lamprey.

What nucleotide change is a shared derived character for species A, B, and C, but not for species G?

Changing the second G to an A is common to species A, B, and C, but not to species G.

What does the principle of parsimony suggest when choosing a phylogenetic tree?

The tree that requires the fewest mutations is preferred.

What does it mean if the genus Quercus (oaks) is monophyletic?

All species of oaks are descended from a common ancestor.

What are molecular clocks primarily based on?

Rates of neutral mutations.

What is a shared primitive character of mosses, ferns, conifers, and flowering plants?

Chlorophylls a and b.

Which type of organism is most likely to be fossilized?

A common thick-shelled crustacean.

What situation is most likely to form a fossil under normal environmental conditions?

An elephant that died at the edge of a waterhole.

Which three organelles in eukaryotic cells contain genetic material?

Mitochondria, chloroplasts, and the nucleus; formed through an endosymbiotic relationship.

Can archeologists find a fossil of a deer that was decomposed before being buried?

Yes, because its skeleton could have been replaced by minerals to form a fossil.

What is the most widely accepted hypothesis regarding the origin of the nuclear genome?

An endosymbiotic relationship between an archaeon and a bacterium.

From where are the genes involved in transcription and translation in eukaryotes derived?

Ancient bacteria.

What is hypothesized to have led to the origin of mitochondria and chloroplasts?

Prokaryotic cells that became internal symbionts within an early eukaryotic cell.

Is the statement true or false: The eukaryotic genome is comprised entirely of genes derived from Archean ancestors?

False.

What is the term for the time it takes for half of a radioactive isotope to decay?

Half-life.

What type of cells were the first living cells likely to be?

Anaerobic, prokaryotic.

What gas increased in the atmosphere due to photosynthetic organisms?

Oxygen.

What is the process called by which major land masses shift their positions?

Continental drift.

What were the consequences of increased oxygen in the atmosphere during and after the Silurian Period?

Conquest of land by arthropods and vertebrates, and an increase in animal body sizes.