Bio QuestionBank: Prokaryotes, Eukaryotes & Viruses

Comprehensive review flashcards in fill-in-the-blank format covering prokaryotic biology, eukaryotic and protistan evolution, and viral mechanics from the Bio QuestionBank.

Fossil evidence of the earliest living organisms dates back about __________.

3.8 billion years

The fossil record extends approximately __________ back in time.

3.5 billion years

Conditions on early Earth differed from modern Earth because only early Earth was intensely bombarded by __________.

large space debris

Unlike Earth's modern atmosphere, primitive Earth's atmosphere did not contain __________.

free oxygen

The first genetic material to exist on early Earth was most likely __________.

RNA

Fossilized stromatolites resemble structures formed by bacterial communities found today in some __________.

shallow marine bays

In $3.5\text{-billion-year-old}$ stromatolite microfossils, the discovery of a __________ would be surprising because eukaryotes had not yet evolved.

nucleus

In bacteria, small circular molecules of DNA that replicate independently of the chromosome are called __________.

plasmids

A prokaryote's essential genetic information is localized in the region called the __________.

nucleoid

The external hair-like bacterial appendages that allow cells to join together for gene transfer are called __________.

pili

The motor of a typical prokaryotic flagellum is embedded within the __________ and plasma membrane.

cell wall

Bacterial binary fission resembles eukaryotic mitosis because both processes produce __________ daughter cells.

genetically identical

Archaebacteria differ structurally from eubacteria primarily in their absence of __________ in the cell wall.

peptidoglycan

The fundamental basis for dividing prokaryotes into bacteria and archaea was genetic traits such as __________ sequences.

ribosomal RNA

Genetic variation in bacterial populations cannot result from __________.

meiosis

If an $E.\,coli$ strain lacks an F factor and phages are absent, beneficial mutations can still be horizontally transferred via __________.

transformation

A bacterium regenerating from an endospore that lacked its parent's plasmids will probably lack __________ genes.

antibiotic-resistant

If all prokaryotes suddenly vanished from the planet, the recycling of __________ would be greatly reduced.

nutrients

A bacterium living in the human intestine and digesting food contents is nutritionally classified as an __________.

anaerobic chemoheterotroph

In an $E.\,coli$ evolution experiment, if the vertical axis is Darwinian fitness, the most valid measure is the number of offspring or close kin that survive to __________.

reproductive age

Based on Table 24.1, the species that is most self-sustaining in environments lacking fixed nitrogen or carbon is __________.

species E

Based on Table 24.1, the species most likely to be found both in sewage treatment plants and the guts of cattle is __________.

species B

Based on Table 24.1, the two species that might cooperate metabolically in a biofilm where one generates methane and the other consumes it are __________.

species A and B

The greatest ecological impact organisms have ever had was when early cyanobacteria released oxygen during the __________ step of photosynthesis.

water-splitting

Endotoxins are composed chemically of __________, whereas exotoxins are proteins.

lipopolysaccharides

An organism that obtains both carbon and energy by ingesting prey or decomposing organic matter is a __________.

chemoheterotroph

When Bdellovibrio bacteriovorus penetrates a gram-negative prey cell with a slimy layer, it crosses structures in the sequence: capsule, outer LPS membrane, __________, and plasma membrane.

peptidoglycan

Bacteria in high-sugar preserves die primarily due to __________ from the cell.

water loss

The chronological sequence in the origin of life is: synthesis of organic monomers, synthesis of organic polymers, formation of __________, and formation of DNA-based genetic systems.

protobionts

According to the endosymbiotic theory, mitochondria originated from engulfed, originally free-living __________.

proteobacteria

Plastids that are surrounded by more than two membranes serve as direct evidence of __________.

secondary endosymbiosis

The eukaryotic supergroup containing red algae, green algae, and all land plants is __________.

Archaeplastida

The oldest taxonomically resolved eukaryotic fossil is a red alga that lived __________ ago.

1.2 billion years

In colonial organisms, plant cell colonies adhere primarily by cell walls, whereas animal cell colonies are held together by __________.

proteins

The two parasitic protist genera that evade human immunity by frequently altering surface proteins are __________ and Trypanosoma.

Plasmodium

A snail-like, coiled porous test composed of calcium carbonate is characteristic of __________.

foraminiferans

Giardia cysts are functionally most analogous to the __________ of bacteria.

endospores

All protists are cellularly classified as __________.

eukaryotic

All protists possess __________, though in some anaerobic lineages they are degenerate and termed mitosomes or hydrogenosomes.

mitochondria

An endosymbiont cyanelle is determined to have transitioned into an organelle once genes have transferred from the cyanelle genome to the __________.

nuclear genome

In Paulinella chromatophora, photosystems are embedded in the __________ of the two surrounding phospholipid bilayers.

innermost

Dinoflagellates characteristically possess __________ flagella.

two

The last common ancestor shared by fungi and animals was most likely a __________.

single-celled eukaryote

In retroviruses, the enzyme reverse transcriptase synthesizes DNA using __________ as a template.

viral RNA

RNA viruses exhibit unusually high mutation rates because viral genome replication lacks __________.

proofreading

A virus's host range is determined by specific surface proteins on the virus and complementary receptors on the __________.

host

If yellow mottle virus has a capsid of 180 identical capsomeres across 20 facets, each facet is composed of __________ proteins.

9

If a bacterium is infected by a chimeric phage with T2 proteins and T4 DNA, the progeny phages will have __________ protein and T4 DNA.

T4

According to Table 17.1, the virus that meets the requirements of a retrovirus is __________.

Virus D

Herpesvirus causes recurring lifelong flare-ups because viral genome copies remain as mini-chromosomes inside host cell __________.

nuclei

To remain latent within an infected cell, herpes simplex virus must shut down host cell __________.

apoptosis

Within plant hosts, viral infections spread cell-to-cell primarily through microscopic channels called __________.

plasmodesmata

An unknown pathogen can be distinguished as bacterial rather than viral because only bacteria can grow alone on a __________.

nutrient medium

The best predictor of the long-term tissue damage caused by a virus is the infected host cell's ability to undergo __________.

normal cell division

During the lysogenic cycle of lambda phage, the viral genome replicates synchronously along with the __________.

host genome