Chapter 23
The protists are divided into how many supergroups?
- 6
What does a capsule do for bacteria?
- A capsule enables a prokaryotic cell to adhere to surface and to other cells, and, most important, to evade an immune response by interfering with recognition by phagocytic. Therefore, a capsule often contributes to the ability of bacteria to cause disease
Eukaryotes are distinguished from prokaryotes by the presence of which of the following?
- A cytoskeleton and compartmentalization, which includes a nuclear envelope and organelles
Lipopolysaccharide
- A lipid with a polysaccharide molecule attached; found in the outer membrane layer of gram-negative bacteria; the outer membrane layer protects the cell wall from antibiotic attack.
What type of prokaryote might have formed endosymbiotic relationships with other larger bacteria, eventually evolving into a chloroplast?
- A photosynthetic bacterium
A prokaryotes cell wall is complex
- A prokaryotes cell wall consists of peptoglycan, a polymer composed of a rigid network of polysaccharide strands cross-linked by peptide side chains.
Which of the following is a branch of the super-group Chromalveolata that is distinguished from other protists by the presence of flattened vesicles stacked in a continuous layer beneath their plasma membrane.
- Alveolates
In members of the branch of supergroup Chromalveolata known as the alveolates, a common tail is the presence of flattened vesicles below the plasma membrane called which of the following?
- Alveoli
Archaea and S-layer
- Among the archaea, the S-layer is almost universal and can be found outside of a pseudomurein layer or, in contrast to the bacteria, maybe the only rigid layer surrounding the cells.
Spore-forming parasites of animals that are characterized by a structure at one end of the cell that facilitates the invasion of a host are members of what group?
- Apicomplexans
Protist Mixotrophs
- Are both phototrophic and heterotrophic
Pili
- Are structures that occur on the cells of some gram-negative prokaryotes. They are shorter than prokaryotic flagella and only about 7.5 to 10 nm thick. Pili can be used to attach a cell to a surface, and may be important in allowing colonization of tissues by pathogens. Some pili are adapted to be involved in the sharing of genetic information, and other specialized pili may also be used to cause a cell to "twitch," which can result in directional movement.
Select all features of water molds
- Asexual reproduction - Motile spores -Sexual reproduction
lytic steps
- Attachment: the virus contacts and becomes specifically bound to the cell. This step limits the host range and the tissue tropism of viruses, as viral surface proteins bind to specific proteins on the surface of he cell. - Penetration: results in the entry of the viral genome into the host cell. - Release: mature virus particles are released, either through the action of virally encoded enzymes that lyse the host cell or by budding through the host cell wall.
Photosynthetic protist are called which of the following?
- Autotrophs
Identify the three basic forms of prokaryotes
- Bacillus - Spirillum - Coccus
The majority of cases of peptic ulcer disease are caused bu which of the following?
- Bacteria
Which of the following is the best definition of endosymbiotic bacteria?
- Bacteria that live within other cells and perform specific functions for thir host cells.
Endosymbiotic bacteria
- Bacteria that live within other cells and provide some benefit for their host cells
How could a bacterial fermentation differ from eukaryotic fermentation in muscle?
- Bacterial fermentation's can produce acids, alcohol, or both; fermentation in muscle only produces acid (lactate)
Which of the following viruses uses the cellular machinery of a bacterium for its own replication?
- Bacteriophage
Why is it difficult to classify influenze based on their host?
- Because there are four types of influenza viruses that can infect many different hosts (humans, birds, pigs, dogs, cats)
Why would you expect to get different results from phylogenetic analysis of nuclear DNA versus plastid DNA?
- Both the red and green algae obtained their chloroplasts through endosymbiosis, possibly of the same lineage of photosynthetic bacteria. The red and green algae had diverged before the endosymbiotic events, and the history recorded in their nuclear DNA is a different evolutionary history than that recorded in the plastids derived through endosymbiosis.
The capsid of naked viruses is assembled from many copied of only a few different proteins. How might this keep the genomes of these viruses very small?
- By encoding only a few proteins to make a capsid, only a few genes are required; fewer genes means a smaller genome
How are eukaryotic cells distinguished from prokaryotes?
- By the presence of a more complex cytoskeleton and compartmentaization
What group of protists primarily dwell in the soil, use either flagella or pseudopods for movement, and sometimes have shells made of silica?
- Cercozoans
Which of the following protist groups is most closely related to the land plants?
- Charophyta
Which of the folowing protists groups is most closely related to the land plants?
- Charophyta
Green algae include which of the following protist groups?
- Chlorophytes - Charophytes
Which of the 6 supergroups isn't monophyletic (descended from a common evolutionary ancestor)?
- Chromalveolata
Which of the following describes mitosis?
- Chromosomes are separated into two daughter cells
Which of the following are methods and/or structures that protists utilize for movement?
- Cilia - Flagella - Pseudopods
What other types of studies might connect choanoflagellates with sponges?
- Comparative genomic studies of choanoflagellates and sponges would be helpful. Considering the similarities among a broader range of genes than just the conserved tyrosine kinase receptor would provide additional evidence.
Some plasmids pick up antibiotic resistance genes and transfer these genes to other prokaryotes via which of the following?
- Conjugation
How would you determine if amoeboid locomotion using pseudopods was a good trait to use in reconstructing protist phylogenies?
- Construct phylogenies with other traits, including DNA sequences. Then map the presence of amoeboid locomotion with pseudopods on to the other phylogenies. If the pseudo-pod trait is not clustered, it is likely that it evolved independently multiple times and is thus not a good trait to use in reconstructing protist phylogies
Gram-negative bacteria
- Contain less peptidoglycan and do not retain the purple-colored dye
Which of the followin are features of at least some ciliates?
- Contractile and food vacuoles - Alveoli under the plasma membrane - a macronucleus and a micronucleus -Cilia for locomotion
How does a contactile vacoule regulate osmotic pressure in a Euglena cell?
- Contractile vacuoles collect and remove excess water from within the Euglena
How cold you distinguish between primary and secondary endosymbiosis by ooking at micrographs of cells with chloroplasts?
- Counting the number of cell membranes of chloroplasts indicates primary or secondary endosymbiosis
Who developed the classification of viruses based on genome expression?
- Developed by Nobel laureate David Baltimore
Which of the following are particularly susceptible to Toxoplasma parasites?
- Developing fetuses, infected by Toxoplasma parasites that have crossed the placental barrier - Patients with AIDS
Stramenopile protists with elaborately ornamented double shells made of silica are called which of the following?
- Diatoms
Because of its simple developmental system, this cellular slime mold is used as a model organism in studies of cell differentiation.
- Dictyostelium discoideum
Infoldings of the prokaryotic plasma membrane gave rise to the endomembrane system that includes which of the following?
- Endoplasmic reticulum (ER) and nuclear envelope
How did eukaryotic cells evolve?
- Eukaryotic cells evolved not only through horizontal gene transfer, but also through infolding of membranes and by engulfing other cells
What are the 6 supergroups to sort out eukaryotes?
- Excavata - Chromalveolata - Rhizaria - Archaeplastida - Amoebozoa - Ophisthokonta
True or false: All multicellular organisms are descended from a single ancestral multicellular protists
- False: multicellularity has arisen multiple times among eukaryotes
What mechanisms allow protists to move?
- Flagellar rotation - Pseudopods
What is the effect of the initial acute disease episode after infection with an HSV-1 or HSV-2?
- Formation of painful blisters at the site of infection
How old is the first early eukaryotic fossil?
- Fossil algae that lived in Siberia 1 BYA
The nucleus and the ER of eukaryotes are thought to have evolved how?
- From infoldings of the plasma membrane
Antigenic drift
- Genetic change seen in certain RNA viruses due to random mutation caused by errors in genome replication
What process can identify the two types of bacteria ?
- Gram stain
Chlorophytes and charophytes are two lineages of which type of protist?
- Green algae
Group II
- Group II viruses have single stranded DNA genomes and must convert them to double stranded DNA to be expressed and replicated in host cells
Group III
- Group III viruses have double-stranded RNA genomes. One strand of the genome is transcribed to produce mRNA that can be translated by host cell machinery. Because many host cells cannot create RNA using information in an RNA template, the enzyme to do this must often be carried inside the virus.
Group IV and Group V
- Group IV and Group V viruses have plus (+) sense and minus (-) sense single-stranded RNA genomes respectively. Plus sense RNA can be translated to make protein. Minus-sense RNA is the complement of plus sense RNA and cannot be translated. A minus-sense RNA genome must be converted to plus-sense RNA by a viral protein before it can be used for translation, or to make new copies of genome.
Group VI
- Group VI viruses are the retroviruses. These viruses have plus-sense single-stranded genomes, but have to be converted into double-stranded DNA to be expressed, and used to make new RNA genomes.
Gram-positive bacteria
- Have a thicker peptidoglycan wall and stain purple
WHat are the two basic structures of viruses?
- Helical and Icosahedral
Select all evolutionary mechanisms that were important in the early evolution of eukaryotes
- Horizontal gene transfer - Engulfing other cells
Which of the following are the two types of structure typical of most viral capsids?
- Icosahedral or helical
Bacteria cell wall
- In bacteria, the structure of the cell wall can be used as the basis of creating two groups: the gram-positive and the gram-negative bacteria
What are the two main ways in which a virus can spread to infect secondary sites in the human body?
- In blood or lymph - Via neurological tissue
Tikvah Alper and John Stanley Griffith
- In the 1960's, both British researches noted that infectious TSE preparations remained infectious even after exposure to radiation that would destroy DNA or RNA.
After the initial acute disease (painful blisters) subsides due to an immune response, where can HSV-1 and HSV-2 be found?
- In the nuclei of sensory neurons that innervate the site of infection
How does HIV compromise the human immune system, allowing opportunistic infections to invade the body?
- Infected CD4+ cells are killed until few are left
Order different types of organisms according to their appearance in the fossil record starting with the oldest at the top. - Reptiles -First land animals -Invertebrates -Flowering plants -Amphibians
- Invertebrates - First land animals - Amphibians - Reptiles - Flowering plants
Group VII
- Is a recent addition tot he classification and contains only a hand full of viruses. These viruses have double-stranded DNA genomes, but there are gaps in some of the DNA strands, so parts of the genome are single-stranded. Replication and expression involves the production of a plus-sense RNA intermediate that is converted to double-stranded DNA by reverse transcription.
Select all features of the feeding phase of a plasmodial slime mold
- It does not have cell walls. - It has multiple nuclei
What is the average size of a bacillus?
- It is anywhere from 0.5 um to 3um in diameter and up to 15 um long
What is the consequence of the destruction of CD4+ cells by HIV to the human body?
- It is no longer defended against invading bacteria and viruses, leading to opportunistic infections
Would you say that cellular slime molds are closely related to plasmodial slime molds?
- It is unlikely that cellular and plasmodial slime molds are closely related. They both appear in the last section of this chapter because they have yet to be assigned to clades. The substantial differences in their cell biology are inconsistent with a close phylogenetic relationship
What might be the benefit of lysogeny to lysogenic phage?
- It provides a means of vertical transmission of the viral genome when the hist cell divides
How could you distinguish between the sporophyte and the gametophyte of a brown alga?
- Just based on outward appearances, the sporophyte of brown algae forms a larger blade like structure, whereas the gametophyte is a small filamentous structure
Who was the first to propose the theory of endosymbiosis?
- Konstantin Mereschkowsky in 1905
Characteristics of euglenozoans
- Lack cell wall - have strips of protein encircling the cell - change shape when they swim
Choose the three types of persistent human viral infections based on the amount of virus present and when it is produced.
- Latent - Slow - Chronic
The undulating membrane of parabasalids is used in which of the following?
- Locomotion
Which scientist settled the argument over spontaneous generation?
- Louis Pasteur
Regarding bacteriophage, during which type of cycle does the phage enter a latent phase, allowing it to be replicated with the host cell?
- Lysogenic
Of the following list, which are the two most important types of cells killed by HIV?
- Macrophages - T-helper cells
From what did the endoplasmic reticulum and nucleus arise from?
- Many prokaryotes have infoldings of their outer membranes extending into the cytoplasm that serve as passageways to the surface. The network of internal membranes in eukaryotes is called the endoplasmic reticulum (ER), and the nuclear envelope, and extension of the ER network that isolates and protects the nucleus, is thought to have evolved from such infoldings.
Prokaryotes structures
- Membrane folds: increase surface area and hold photosynthetic proteins. - Nucleoid region: circular DNA chromosomes are condensed to form a visible region - Ribosomes: are smaller than those of eukaryotes and differ in protein and RNA content. - Inclusion bodies: Many prokaryotes accumulate materials in cellular aggregations called inclusion bodies. Some materials are stored as sources of carbon or as reservoirs of chemical potential energy such as glycogen.
The genome of influenza viruses is composed of eight pieces of minus-sense RNA. How are these viruses classified using the Baltimore classification?
- Minus sense RNA viruses are in Baltimore group V
Which of the following statements about amoebais correct?
- Most amoeba are free-living, but some are parasitic, and they live int he soil as well as frehswater
Peptidoglycan is an important component of the cell walls of which microbes?
- Most bacteria
How did multicellularity come to be?
- Multicellular organisms likely arose from colonial protists
Which of the following is the best description of how many times multicellularity has arisen?
- Multiple times among the eukaryotes
Who developed the Gram stain technique?
- Named after Hans Christian Gram-Danish bacteriologist, 1853-1938
Assimilation of external DNA fragments from dead bacterial cells is called which of the following?
- Natural transformation
Animals, fungi, and choanoflagellates are members of what supergroup?
- Opisthokonta
Choose all the conventional systematic groups that are also used to classify viruses.
- Order - Genus - Family
How do autotrophs obtain carbon?
- Oxidized
What is the space between the outer membrane and the peptidoglycan called?
- Periplasmic space
What are some heterotrophic protists?
- Phagotrophs: these are organisms that ingest particles of foood into vesicles called food vacoules or phagosomes. Lysosomes fuse with the food vacoules, introducing enzymes that digest the food particles within. Digested molecules are absorbed across the vacuolar membrane.
From what did chloroplast evolve from?
- Photosynthetic bacteria were liekly engulfed by other, larger bacteria, leading to the evolution of chloroplasts, which are the photosynthetic organelles of plants and algae.
Which of the following are nutritional strategies found in protists?
- Phototrophs - Phagotrophs - Mixotrophs
Which of the following are used by foraminifera to reinforce their tests?
- Pieces from shells of marine invertebrates - Sand grains - Calcium carbonate
Which of the following are important features of eukaryotes that distinguish them from prokaryotes?
- Presence of organelles such as mitochondria and chloroplasts - presence of cytoskeleton - Presence of a nucleus
What disease agents are infectious proteins that can cause transmissible spongiform encephalopathies?
- Prions
What replicates faster prokaryotic or eukaryotic cells?
- Prokaryotic cells that are smaller than eukaryotic cells can rapidly absorb nutrients, grow rapidly, and quickly replicate thir chromosomes.
Rank the following cells and particles in order according to size, with the smallest at the top and largest at the bottom.
- Protein - T2 bacteriophage - Influenze virus - E. coli bacterium Eukaryotic cell
Are protists heterotrophs or autotrophs?
- Protists can be heterotrophic or autotrophic. The heterotrophs obtain energy from organic molecules synthesized by other organisms. Some autotrophic protists are photosynthetic, whereas others are chemoautotrophic
Which of the following best describes reproduction among protists?
- Protists typically reproduce asexually, but some undergo sexual reproduction regularly and others reproduce sexually only at times of stress
Do protists reproduce asexually or sexually?
- Protists typically reproduce asexually. In addition, some undergo sexual reproduction regularly, whereas others undergo sexual reproduction at times of stress, including during food shortages
Members of the supergroups Rhizaria and Amoebozoa primarily use which of the following for locomotion?
- Pseudopods
These organisms are autotrophic protists that lack flagella. They have numerous accessory photosynthetic pigments such as phycoerythrin and range in size from microscopic to over 2 m in length.
- Red algae
Tuberculosis mainly affects which of the following?
- Respiratory system
Which supergroups include organisms that primarily use pseudopods for locomotion?
- Rhizaria - Amoebozoa
What are the basic shapes that prokaryotes exhibit?
- Rod-shaped (bacillus) - Spherical or oval-shaped (coccus) - Long and helix-shaped (spirillum)
Place the following changes in the configuration of Earth's continents in order according to their appearance in Earth's history with the oldest configuration at the top.
- Rodinia formed - Pangea formed - Australia and Antartica separated - A land bridge between Asia and North America formed
Does the information about nitrogen fixation shed any light on the practive of crop rotation?
- Rotating a crop that has a symbiotic association with nitrogen-fixing bacteria will return nitrogen to the soil depleted by other plants.
What is the theory of endosymbiosis?
- Scientists propose that ancestral eukaryotic cells, which already had an internal system of membranes, engulfed aerobic bacteria, which then became mitochondria within the eukaryotic cell. Chloroplasts also originated this way, with eukaryotic cells engulfing photosynthetic bacteria.
What are the two most common routes of HIV transmission?
- Sharing of needles among intravenous drug users - Intimate sexual contact
Radiolarians secrete glassy exoskeletons made of which of the following?
- Silica
The genome of HIV consists of two identical _________ stranded, ______________ - sense RNA molecules
- Single - Plus
Which of the following are reasons why classifying viruses by disease they cause can be impractical?
- Some viruses can cause different disease in different context - The same disease can be caused by many different viruses - Some viruses do not appear to cause any disease
Gram stain
- Staining technique that divides bacteria into gram-negative or gram-positive based on retention of a violet dye. Differences in staining are due to cell wall construction.
Which of the following are sexually transmitted diseases caused by bacteria?
- Syphilis - Gonorrhea - Chlamydia
Conjugation
- Temporary union of two unicellular organisms, during which genetic material is transferred from one cell to the other; occurs in bacteria, protists, and certain algae and fungi
What would be a major difficulty in finding a poison to fight the malaria-causing protist Plasmodium?
- The Plasmodium often becomes resistant to new poisons and drugs. And, because the Plasmodium has multiple hosts, a drug for humans wouldn't eradicate the Plasmodium in other stages of its life cycle in the mosquito.
Which of the following support the RNA world hypothesis? - The RNA molecule may have been the first nucleic acid to permit self-replication. - High concentrations of RNA may have occurred in ice crystals in salty water, promoting bond formation. - Ribosomes translate RNA into proteins in the cell. - There was likely little ribose sugar on prebiotic Earth. - Research has shown that it is possible to synthesize RNA without pure ribose.
- The RNA molecule may have been the first nucleic acid to permit self-replication. - High concentrations of RNA may have occurred in ice crystals in salty water, promoting bond formation. - Ribosomes translate RNA into proteins in the cell. - Research has shown that it is possible to synthesize RNA without pure ribose.
What type of cell walls do archaea posses?
- The archaea do not possess peptidoglycan, but some have a similar structure called pseudomurein.
What is the average size of a eukaryotic cell?
- The average eukaryotic cell is about 20 to 25 um in diameter
Flagella
- The central filament of a flagellum is made from a single protein, flagellin. Flagella range in length from 0.3 to 12 um in length, but are only 10 to 20 nm wide. They originate in the cytoplasm, span the cell wall, and project outside the cell, being rotated to propel the organisms in fluid environments.
What major barrier must be overcome for sexual reproduction of land-based organisms?
- The lack of water is the major barrier for sperm that move through eater to reach the egg. It is more difficult for sperm to reach the egg on land.
What does the outer membrane layer do for the gram- negative bacteria?
- The outer membrane layer makes gram-negative bacteria resistant to many antibiotics that interfere with cell-wall synthesis in gram-positive bacteria.
Phage conversion
- The phenomenon by which DNA from a virus, incorporated into a host cell's genome, alters the host cell's function in a significant way; for example, the conversion of Vibrio cholerae bacteria into a pathogenic form that releases cholera toxin.
Transduction
- The process by which viruses can transfer genetic material from one bacterial host to another.
Which of the following occurred during the Cenozoic era of the Phanerozoic eon?
- The seperation of Greenland and North America - The continued growth of the Atlantic Ocean - A rise in sea level - The seperation of Australia and Antartica
Induction
- The switch from lysogeny to a lytic cycle
Which of the following statements about dinoflagellates are true?
- Their chloroplasts are similar to those of diatoms or brown algae. - They have alveoli - They are protected by plates composed of cellulose-like material
Which of the following are true of protists?
- They are eukaryotes - Many are macroscopic, with some being very large
Which of the following describes the ribosomes in mitochondria?
- They are similar to bacterial ribosomes
What are diplomonads, parabasalids, and euglenozoans?
- They are unicellular protists grouped as Excavata based on cytoskeletal and DNA sequence similarities showing evolutionary relatedness.
What is the function of the undulating membranes in parabasalids?
- They are used for locomotion
Which of the following describes the similarity between Diplomonads and parabasalids the best?
- They have modified mitochondria and multiple flagella
Both bacteria and archae have cell walls, but the cell walls are chemically different between the two. Which describes the cell wall of the Archaea?
- They lack peptidoglycan
Both bacteria and archaea have cells walls, but the cell walls are chemically different between the two. Which describes the cell wall of the Archaea?
- They lack peptidoglycan
Which best describes endosymbiotic bacteria?
- They live within other cells and perform specific functions for their host cells
Which of the following statements best describes viral genomes?
- They may be circular or linear, single-stranded or double-stranded, and composed of DNA or RNA
Choose all the characteristics of acute viral infections
- They often (although not always) establish at the site of infection - They result in the sudden symptom onset - They involve rapid viral replication
If you performed a gram stain on a gram-positive species but forgot to treat the cells with the iodine, how would they appear through a microscope?
- They would appear light pink due to the counter-stain. The iodine helps to trap the first purple stain in the cytoplasm and without it, the stain would be washed out before the second, light pink, stain was applied.
During this process, DNA enters bacterial cells via viral vectors
- Transduction
When does transformation occur?
- Transformation occurs when one bacterial cell has died and ruptured, spilling its fragmented chromosomal DNA, or plasmids, into the environment. This DNA can be absorbed by another cell and incorporated into its genome, thereby " transforming" it.
True or false: Prokaryotes have systems in place for both innate and adaptive defenses against viral attack.
- True
In what type of habitat would it be useful to use undulating membranes for locomotion?
- Undulating membranes would be effective on surfaces with curvature that may not always be smooth, such as intestinal walls
Characteristics of Diplomonads
- Unicellular organisms - absence of functional mitochondria - Presence of multiple posterior flagella and two haploid nuclei per cell
Chemoorganoheterotrophs
- Use reduced (organic) carbon made by producer organisms as sources of carbon, electrons, and energy. All animals are chemoorganoheterotrophs
Viral genomes are highly diverse
- Viral genome are either DNA or RNA, linear or circular, and single or double stranded
Which infectious agents are composed solely of RNA?
- Viroids
How big are viruses?
- Viruses are significantly smaller than cells, having diameters from about 20 to 250 nm.
Group I
- Viruses in group I have double-stranded DNA that use host machinery ot replicate and express their genomes
Which of the following diseases are the result of an infection by a pathogenic bacterium?
- Whooping cough - Tetanus - Cholera - Pneumonia
Budding (asexual)
- a form of asexual reproduction that produces a daughter cell that is considerable smaller than its parent and then grows to adult size.
Endospores
- a thick wall develops around their genome and a small amount of cytoplasm when they are exposed to environmental stress. These endospores are highly resistant to environmental stress such as hear, and when environmental conditions improve, they can germinate and return to normal cell division to form vegetative cells after decades or even centuries of dormacy.
Bacteria and _____________ are collectively referred to as prokaryotes
- archae
Prions
- are infectious particles that dont contain any nucleic acid
Viroids
- are naked molecules of circular RNA, ranging in size from about 250 to 400 nucleotides, some of which cause severe disease in economically important crops.
Bacteriophage
- are structurally and functionally diverse viruses that infect only bacteria
Organisms that can produce all the organic carbon compounds they need to survive from CO2 are known as which of the following?
- autotrophs
Chlamydia, siphilis, and gonorrhea are all examples of
- bacterial sexually transmitted diseases
The use of organisms to remove pollutants from water, air, and soil is called ______________
- bioremediation
Schizogony
- common among some protists, cell division is preceded by several nuclear divisions. This allows cytokinesis to produce several individuals almost simultaneously
Prokaryotes have an important role in the recycling of carbon through the biosphere via the processes of ___________ and ___________
- decomposition - fixation
Protists that possess two flagella, plates made of a cellulose-like material, and may be bioluminescent or produce toxins are ___________
- dinoflagellates
Cytokinesis
- division of the cytoplasm
True or False: The role of bacteria and archaea int he cycling of carbon is very limited
- false
All of the following are means of horizontal gene transfer except?
- from parent to offspring
Some protists, such as amoebas, are surrounded only by their plasma membrane whereas others such as diatoms are foraminifera are surrounded by
- glassy shells of silica
The ___________________ life cycle of the brown algae is marked by alternation of generations between multicellular sporophyte and gametophyte generations.
- haplodiplontic
The basic structure of a virus
- has a genome of RNA or DNA - the genome is surrounded by a protein shell called a capsid
Characteristics of parabasalids
- have an undulating membrane that is used for locomotion - use flagella to propel themselves - have semifunctional mitochondria and have one nucleus per cell
Most viruses have a capsid that is __________ or _______________ in terms of its basic structure and symmetry.
- helical - icosahedral
The earliest eukaryotic cells evolved through the transfer of genes across species boundaries, a process called _______ gene transfer.
- horizontal
S-layer
- in some bacteria and archaea, an additional protein or glycoprotein layer forms a rigid para-crystalline surface, outside of the peptidoglycan or outer membrane layers of gram-positive and gram-negative bacteria.
HA and NA
- in the viral envelope are the two viral proteins most commonly recognized by the immune system
What is a icosahedron?
- it is a structure with 20 equilateral triangular facets. (most animal virus capsids are icosahedral)
Which of the following describes the horizontal transfer of genes?
- it is between different bacteria
How does natural transformation occur?
- it occurs when a cell dies and releases its contents to the surrounding environment.
Bacteriophage exhibit two reproductive cycles: the _______________ cycle, in which the latent phage is replicated with the host cell, and the ________ cycle, which phage undergo replication within the host cell, eventually causing it to rupture.
- lysogenic -lytic
What does endosymbiosis mean?
- means "living together in close association"
Amoebas are surrounded only by their plasma __________
- membrane
Early taxonomies used characteristics which were easily observable or detectable with the use of a ____________________ to classify prokaryotes.
- microscopes
During cell division, the separation of replicated chromosomes into two daughter cells is called _________
- mitosis
Which of the following are characteristics used by early taxonomists to classify prokaryotes?
- motile or nonmotile - unicellular or filamentous or colony-forming -human pathogen or not - photosynthetic or nonphotosynthetic
Amoebas use their pseudopods to
- move - engulf food
Diplomonads are unique because they possess two _________________ per cell.
- nuclei
Organotrophs
- obtain electrons from reduced carbon sources
Litotrophs
- obtain electrons from reduced inorganic substances in the environment
phototrophs
- obtain energy by harvesting from light
Chemotrophs
- obtain energy by oxidizing reduced chemicals obtained from the environment
Specialized transduction
- only specific genes can be transferred
The cell walls of most bacteria are composed of _______________ which is not present in archaea
- peptoglycan
The most fundamental characteristics of which of the following cell types is simple interior organization?
- prokaryotic
Euglenozoans exhibit extreme flexibility; they change shape while swimming thanks to strips of ________ encircling their cells rather than a cell wall.
- protein
A eukaryotic organism that lacks the characteristic necessary to be classified with animals, plants, or fungi is a(n) _________
- protist
Many amoebas move with "false feet," known as ___________
- pseudopods
A disease that was prominent in the past, and whose incidence suddenly increases after a period of low incidence, is called a ____________ disease.
- re-emerging
How do heterotrophs obtain carbon?
- reduced form
Mitochondria can synthesize proteins with their own __________ which are very similar to those of bacteria in size and structure.
- ribosomes
Mitosis
- separation of chromosomes
Protists can exhibit both ____________ and _____________ reproduction.
- sexual -asexual
Which is the most fundamental characteristic of a prokaryotic cell?
- simple interior organization
Transformation
- some species of bacteria can also pick up genetic material directly from the environment
Apicomplexans are _______________-forming parasites of _____________.
- spores - animals
Foraminifera produce pore-studded shells, called ______________ they are made of organic materials, reinforced with grains of ___________ ______________, sand, or even plates from the shells of invertebrate animals.
- tests - calcium - carbonate
What other additional gelatinous layer is seen in bacteria?
- the capsule, surrounds the other wall layers and can be detected relatively easily bu staining the microcospy.
Phage conversion is
- the change in the phenotype of a lysogenic bacterium caused by the prophage
Transmissible spongiform encephalopathies (TSEs) cause
- the development of numerous small cavities int he brain as neurons die
Functions of the S-layer
- the functions of the S-layer are diverse and variable; they can attach the cell to a surface, afford protection to the cell, trap molecules close to the cell surface, or act as a selectively permeable structure.
Oomycetes are distinguished from other protists by
- the structure of their motile spores
Oomycetes are distinguished from other protists by ____________
- the structure of their motile spores
What does the term "prokaryote" describe?
- the term prokaryote describes a cell type, or collectively the organisms in the Domains Bacteria and Archaea.
What do amoebas use their pseudopods for?
- to move or engulf their food
True or false: prokaryotes have systems in place for both innate and adaptive defenses against viral attack.
- true
The genome of HIV consists of
- two single-stranded, plus-sense RNA molecules
Which of the following are atypical viral shapes that have so far been observed only in Archaeal viruses?
- two-tailed -spindle-shaped - bottle-shaped
Generalized transduction
- virtually any gene can be transferred between cells
In the Baltimore classification of viruses, there are ______ groups of viruses and every known virus can be placed in only one such group based on the way it _________ its genome.
-7 - replicates
Bacteria-infecting viruses are also known as which of the following?
-Bacteriophage
Stanley Prusiner
-Concluded that the infectious agent was a protein that he names a prion (proteinaceous infectious particle)
Viruses that contain ____________ as their genetic material are often assigned to species group; the same is not true of viruses with _________ as their genetic material
-DNA -RNA
What is the gram-negative cell-wall made up of?
-In the gram-negative bacteria, a thin layer of peptidoglycan is sandwiched between the plasma membranes and a second outer membrane. The outer membrane contains large molecules of lipopolysaccharide, lipids with polysacharide chains attached.
Why can influenza virus, but not HIV, undergo antigenic shift?
-Influenza viruses have eight genomic segments that can get shuffled up and redistributed during infections involving multiple different strains of influenza; HIV doesn't have genomic segments so they cannot be shuffled
Select all features of dinoflagellates
-Photosynthetic - Two flagella
Who were the first eukaryotes?
-Protists
Viral genomes may be composed of _______________ or _______________ and may be ____________-stranded or _________-stranded
-RNA -DNA -single -double
Radiolarians secrete glassy exoskeleton made of which of the folowing?
-Silica
In the mutualistic symbiosis between nitrogen-fixing bacteria and plants, what benefit do the plants provide the bacteria?
-Sugars
Cholera, Lyme disease, scarlet fever, and pneumonia are all examples of diseases caused by
-bacteria
Even though chloroplasts of different algae are not monophyletic, it is thought that all chloroplasts derived from a single line of _____________
-cyanobacteria
The return of atoms found in living things tothe physical environment after organisms die is called
-decomposition
Cellular slime molds are important model organisms used in the study of cell
-differentiation
Capsule
-in bacteria, a gelatinous layer surrounding the cell wall
Unlike horizontal gene transfer, ___________ gene transfer occurs when genes are passed from one generation to the next.
-vertical
The first organisms sand only living cells on Earth for more than a billion years were ________ and __________
1) Archea 2) Bacteria
Supergroups of Eukaryotes
1) Excavata: Organisms lacking typical mitochondria 2) Chromalveolata: organisms with chloroplasts obtained through secondary endosymbiosis 3) Archaeplastida: organisms with chloroplasts for photosynthesis 4)Rhizaria: organisms with slender pseudopods used for movement 5) Amoebozoa: organisms with blunt pseudopods used for movement 6) Opisthokonta (fungi, animal ancestors, and animal)
Characteristics of an outgroup?
1) It is closely related to the group under study, but is not a member of the group. 2) It can be used to polarize characters
The idea that RNA may have been the first nucleic acid to permit self-replication and the fact that ribosomes translate RNA support the ________ _______ hypothesis.
1) RNA 2) world
What is true of shared derived characters?
1) They are newer than ancestral characters on an evolutionary timescale 2) They are more informative than ancestral characters
A clade consists of a common ________ species and all of its _________ species.
1) ancestor 2) descendant
Early organisms were thought to be autotrophs with the ability to synthesize complex_________ compounds from simple _________ compounds and later use them as an energy source.
1) organic 2) inorganic
Organisms belonging to domain Eukarya appear in the fossil record about how long ago?
1.5 BYA
Since its formation, Earth has undergone much change. In fact, no rocks have been found from the first ___________
500-700 million years of Earth's history
The current Cenozoic era began about how many years ago? A) 65 MYA B) 25 MYA C) 200 MYA D) 100 MYA
65 MYA
Biologists believe that the first living things on Earth had the ability to synthesize complex organic compounds from simple inorganic compounds and later use them as an energy source. Therefore those organisms were which of the following? A) Autotrophs B) Heterotrophs C) Decomposers D) Consumers
A
Carbon dioxide in the atmosphere combines with water to form which acid? A) Carbonic Acid B) Phosphoric Acid C) Sulfuric Acid D) Nitric Acid
A
Compared to today's atmosphere, Hadean Earth was which of the following? A) A dynamic environment, shifting between a fiery and sometimes frozen Earth, that was unlikely to have supported life. B) A frozen Earth, that was unlikely to have supported life. C) A fiery Earth that was likely to have supported life. D) A dynamic environment, shifting between a fiery and sometimes frozen Earth, that could have supported life.
A
Early Earth experiences temperautes over which of the following? A) 2000 C B) 500 C C) 100 C D) 1000 C
A
Evidence indicates that carbon fixation is which of the following? A) It is an ancient process B) It arose with the evolution of algae C) It arose with the evolution of terrestrial plants D) It has only recently evolved
A
One way of looking for evidence of ancient life is to look for organic molecules that are clearly of biological origin; such molecules are called which of the following? A) Biomarkers B) Amino Acids C) Fatty Acids D) Hydrocarbons
A
Some of the oxygen formed as a result of photosynthesis may have combined with which of the following metals in the ocean? A) iron B) calcium C) sodium D) potassium
A
The current Cenozoic era began about how many years ago? A) 65 MYA B) 200 MYA C) 25 MYA D) 100 MYA
A
The first 500-700 million years of Earth's history comprised an eon called which of the following? A) Hadean Eon B) Proterozoic Eon C) Archean Eon D) Phanerozoic Eon
A
Which of the following eras started with the expansive diversification of life of the Cambrian period? A) The Paleozoic era B) The Archaean era C) The Haedean era D) The Phanerozoic era
A
Pseudopods
A "false foot" or temporary bulge of cytoplasm used for feeding and movement in some protozoans (amoebas)
What is the main assumption behind the idea of a molecular clock?
A constant rate of evolution of a molecule
Synapomorphy
A derived character shared by clade members
Stromatolite
A fossilized mat of ancient bacteria formed as long as 2 BYA, in which the bacterial remains individually resemble some modern-day bacteria
Which of the following is true of the beginning of the Paleozoic era?
A great diversification of life occurred and many separate continents existed
What does a cladogram depict?
A hypothesis of evolutionary relationships
Coccus
A spherical bacterium.
Are viruses living?
All viral particles (virions) lack cytoplasm and are not cells, as they generally lack metabolic activity and cannot replicate outside of a host.
Which of the following was produced in experiments on primitive Earth conditions conducted by Miller-Urey and others?
Amino acids
The major evolutionary innovations in cells occurred when life was primarily which of the following?
Aquatic
Viruses with a two-tailed structure, with a bottle shaped structure, and with a spindle-shaped structure have all been observed in __________________
Archaea
Life is thought to have arisen during the _____________ eon.
Archean
Cladistics/shared derived characters
Are considered informative in determining evolutionary relationships CLADISTIC: a method of classification of animals and plants according to the proportion of measurable characteristics that they have in common. It is assumed that the higher the proportion of characteristics that two organisms share, the more recently they diverged from a common ancestor.
A single supercontinent existed in the Southern Hemisphere during the Proterozoic eon; it began to break up into smaller continents approximated 700 MYA. What was this supercontinent called? A) Gondwana B) Rodinia C) Laurentia D) Pangea
B
According to some scientists, the first nucleic acid which permitted self-replication was RNA. This is supported by the well known fact that in addition to storing genetic information, RNA can do which of the following? A) Serve as an inhibitor of metabolic reaction B) Serve as an enzyme to catalyze reactions C) Be used to produce fatty acid D) Be used for energy instead of glucose
B
At the end of the Paleozoic era the Earth formed with of the following? A) A multicontinent B) A single supercontinet C) Two supercontinents D) The 5 continents as seen today
B
Compared to DNA, RNA can be described as which of the following? A) More stable B) Less stable C) Double stranded D) Comprised of deoxyribose
B
Cyanobacteria, algae, and modern land plants use which of the following pathways for carbon fixation? A) Electron Transport System B) Calvin cycle C) Krebs cycle D) Glycolysis
B
Early life may have arisen during which period? A) Ordovician B) Archean C) Silurian D) Cambrian
B
How many years between the origins of photosynthesis and substantial amounts of oxygen int he Earth's atmosphere? A) 100 million B) 200 million C) 400 million D) 300 million
B
If it were possible to conduct sophisticated microscopic and chemical analysis of the oldest known microfossils, one should be surprised to observe evidence of which of the following? I. double-stranded DNA II. a nuclear envelope III. a nucleoid IV. a nucleolus V. nucleic acids A) II only B) II and IV C) II, III, and IV D) III only
B
Multiple lines of evidence indicates that the first cells were most likely which of the following? A) Eukaryotic B) Prokaryotic C) Photosynthetic
B
Under which of the following scenarios is early life on Earth least likely to have arisen? A) In a smelly sea of ammonia, formaldehyde, cyanide, and other chemicals B) In an ice-covered ocean during a Snowball Earth event C) In hydrothermal deep-sea vents D) At the ocean's shore
B
What effect did volcanic eruptions have on the amount of carbon dioxide int he atmosphere and oceans? A) CO2 levels did not change B) CO2 was added to the atmosphere and ocean C) CO2 was removed from the ocean
B
What effect does weathering of rock have on the amount of Carbon dioxide in the atmosphere? A) CO2 levels increase B) CO2 levels decrease C) CO2 levels stay the same
B
What percent of the weight of the Tagish Lake meteorite is organic matter? A) 13% B) 3% C) 8% D) 18%
B
Which of the following compounds in the ocean precipitates and sequesters carbon dioxide? A) KCI B) CaCO3 C) H2CO3 D) NaCI
B
Which of the following factors does not affect the ability of organisms to survive and reproduce? A) Water availability B) Hydrogen availability C) Temperature D) Atmospheric levels of CO2 and O2
B
Which of the following statements is true? A) Enzymes are never proteins B) Most enzymes are proteins C) All enzymes are proteins D) Few enzymes are proteins
B
Identify the Earth's first organisms
Bacteria and Archaea
Why might a species be most phenotypically similar to a species that is not its closest evolutionary relative?
Because of convergent evolution; two distantly related species subjected to the same environmental may be more phenotypically similar than two species with different environmental pressures but a more recent common ancestor. Other reasons or the possible dissimilarity between closest related species include oscillating selection and rapid adaptive radiations in which species rapidly adapt to a new available niche.
Why do we say that bacterial colonial aggregates are not truly multicellular?
Because they lack differentiation and intergration of function
How is a cladogram constructed?
By using shared derived characters are to construct clades within clades.
3.2 billion year old micro-fossils found in deposits which were once microbial mats in shallow South African marine environments provide compelling evidence for the structure of the first _______ A) eukaryotic cells B) terrestrial organisms C) living cells D) photosynthetic cells
C
As carbon dioxide levels in the atmosphere decreased what happened to the temperature on Earth? A) It remained the same B) It warmed C) It cooled
C
Currently the oldest micro-fossils that are supported by isotopic data and by spectroscopic analysis are how many billion years old? A) 5.5 B) 4.5 C) 3.5 D) 1.5
C
During the early and late Proterozoic, life was decimated because of which of the following? A) Several sudden sharp increases in temperature B) Several periods of exceptionally strong temperature fluctuations (over thousands of degrees) C) Three sudden exceptionally sharp drops in temperature
C
Early life may have arisen during the Archean, but evidence of life in the storm of micro-fossils is difficult to interpret for which reason? A) Micro-fossil-like structures can only be preserved for up to 1 billion years. B) Biological processes cannot produce micro-fossil-like structures. C) Non biological processes can produce micro-fossil-like structure D) Rocks older than half a billion years are unchanged over time.
C
Fossilized stromatolites are sedimentary deposits A) that can be used as indirect evidence that microorganisms colonized land approximately 1.5 billion years ago B) that provide evidence that plants moved onto land in the company of fungi around 500 million years ago C) that provide indirect evidence that life began over 2.7 billion years ago D) that contain the first undisputed fossils of eukaryotes from 2.1 billion years ago
C
How has the temperature of Earth changed since the planet's formation? A) The planet had been warming up B) The temperature today is similar to what it was when Earth was first formed C) The planet has been cooling
C
How has the temperature of Earth changed since the planet's formation? A) The planet has been warming up B) The temperature today is similar to what it was when Earth was first formed C) The planet has been cooling
C
It is likely that Earth's first organisms emerged and lived when the Earth was at which of the following temperatures? A) Very low temperatures B) At the same temperatures that support life today C) Very high temperatures
C
It is most likely that Earth's first organisms emerged and lied at very high temperatures about how many years ago? A) 2.5 BYA B) 1.8 BYA C) 3.8 BYA D) 2.8 BYA
C
Life started as a single cell int he Archean eon and then evolved into whichof the following? A) Four kingdoms B) Two domains C) Three domains D) Six supergroups
C
Micro-fossil-like structures as evidence of life can be difficult to find and to interpret for which reason? A) Rocks older than 3 billion years are very fragile B) There are no rocks older than 2 billion years C) Rocks older than 3 billion years change significantly over time
C
The gradual movement of continents due to plate tectonics did which of the following? A) Affected the climate but had no effect on populations and their ability to interbreed B) Did not affect the climate but made it possible for populations to mix and interbreed C) Affected the climate and made it possible for populations to mix and interbreed D) Did not affect the climate and had no effect on population and their ability to interbreed
C
The most common pathway for carbon fixation is which of the following? A) Carboxylation B) Decarboxylation C) Calvin Cycle D) Krebs Cycle
C
What are fossilized forms of microscopic life called? A) Meteorites B) Stromatolites C) Microfossils D) Macrofossils
C
What was the approximate temperature range of the early Earth? A) 2000C to 0C B) -200C to -50C C) 2000C to -50C D) 0C to -50C
C
Which is the most abundant amino acid found in the Tagish Lake meteorite? A) Alanine B) Histidine C) Glycine D) Proline
C
Which of the following describes when single-called organisms were the only form of living organisms? A) When oxygen became available in atmosphere B) Only when the Earth first formed, between 4.6 and 3.8 billion years ago C) For most of the history of life on Earth D) For a short period of the history of life on Earth
C
Rapid diversification of life occurred during which of the following periods?
Cambrian
When examining species, we can look at multiple aspects of the makeup of those organisms, from DNA to behavior. Any such feature that we examine is called a _________.
Character
In a cladogram, what word describes an ancestral species and all of its descendants?
Clade
In multicellular organisms cells should be connected to each other in order to do which of the following?
Communicate with each other
Sexual reproduction allows greater genetic diversit because of which of the following?
Crossing over occurs during meiosis
According to the hypothesis of an RNA world, the first nucleic acid that permitted self-replication was which of the following? A) Thymine B) An amino acid C) DNA D) RNA
D
Changes in concentration of which of the following atmospheric gases have affected the evolution of life on Earth? A) CO2, O2, N2, and Fe+2 B) CO2, O2, N2, and Ca+2 C) CO2, O2, N2, and Cl2 D) CO2, O2, N2, and CH4
D
Climate and atmosphere are some factors A) that do not affect the ability of organisms to survive and reproduce B) that increase life's genetic diversification by causing mutation C) that affect the ability of organisms to speciate D) that effect the ability of organisms to survive and reproduce
D
For most of the history of life on Earth, the only form of living organisms were which of the following? A) Photosynthetic B) Heterotrophic C) Multi-celled D) Single-celled
D
Many microfossils are 1-2 μm in diameter and appear to be single-celled, with no external appendages or internal structure. This suggests that the organisms that were fossilized to form these microfossils resembled which of the following? A) Present-day fungi B) Present-day protista C) Present-day eukaryotes D) Present-day prokaryotes
D
The early atmosphere of planet Earth probably had which of the following? A) High levels of O2 B) Low levels of CO2 C) Equal levels of CO2 and O2 D) High levels of CO2
D
The three modern monophyletic clades called domains evolved from which of the following? A) A single prokaryotic cell in the Cenozoic era B) A single algal cell C) A single fungal cell D) A single primitive cell of the Archean eon
D
Which of the following states is correct regarding the Hadean Earth? A) Hadean Earth had all the atmospheric gases of today's Earth, thus could have supported life. B) Hadean Earth could have supported only Archean life because of Earth's high temperature. C) Hadean Earth had the same concentration of O2 as today's Earth; this provided a good environment for formation of organic molecules. D) Hadean Earth could not have supported life because of the hot mass of molten rock during this period
D
After a branch on the cladogram, each species will share a set of these characters that are not found in species below the branch point.
Derived
Cladogram
Diagram that shows the evolutionary relationships among a group of organisms
What type of virus has more morphological diversity?
Enveloped viruses have much greater morphological diversity than naked viruses due to the flexible nature of their envelope.
Archean Eon
Eon extending from the time that life originated, 3.8 billion years ago, to 2.5 billion years ago.
Life has evolved into three monophyletic clades called domains which are?
Eubacteria, Archaea, and Eukaryotes
True or false: Eukarya are believed to have diverged from the bacterial line of descent. The Eukarya are therefore more closely related to the Bacteria than to the Archaea.
False
True or false: Evidence indicates that carbon fixation is a relatively new process that cells have acquired.
False
True or false: Fossil records indicate that both prokaryotes and eukaryotes evolved around the same time.
False
True or false: Most amoeba are parasites and live in freshwater habitats.
False
True or false: Although it was once thought that bacteria were the causative agent of most peptic ulcers, new evidence suggests that ulcers are usually caused by irritation to the gastrointestinal tract and that bacteria are only rarely involved.
False: Bacteria have only relatively recently been named a causative agent of ulcers, and new evidence suggests that the bacterium Helicobater pylori is involved in the majority of cases.
During the last 2 million years humans and other animals were able to migrate between the disconnected continents of Asia and North America due to which of the following?
Glaciation and a drop in sea level
Which eon would contain rocks with no fossils?
Hadean
Cilia
Hairlike projections that extend from the plasma membrane and are used for locomotion
Some stretches of an organism's genome do not appear to have any function. How does this affect the construction of phylogenies?
Homoplasy can be more common in these regions.
Polarize
In cladistics, to determine whether character states are ancestral or derived
Difference between synapomorphies and symplesiomorphies
In contrast to synapomorphies, symplesiomorphies are not informative about phylogenetic relationships.
Which of the following statements is true of multicellularity?
In multicellular organisms, cells are connected and communicate with each other.
Why is cladistics more successful at inferring phylogenetic relationships in some cases than in others?
In some cases wherein characters diverge rapidly relative to the frequency of speciation it can be difficult to construct a phylogeny using cladistics because the most parsimonious phylogeny may not be the most accurate.
What is the advantage of hacing cyanobacteria living inside a cell?
Intracellular production of glucose
Shared Ancestral character
Is a character that originated in an ancestor of the taxon
Shared derived character
Is an evolutionary novelty unique to a particular clade
Whats another what to look for evidence of ancient life?
Is to look for organic molecules, which are clearly of biological origin; such molecules are called biomarkers
Why is the use of a molecular clock controversial?
It assumes that DNA divergence rates are constant over time.
Sometimes evolution can occur vary rapidly and the number of derived shared characters can be small. In such cases, how is parsimonious analysis affected?
It can be inaccurate and misleading
How does homoplasy affect cladistic analysis?
It causes organisms to seem closely related when they are not
Which of the following statements about the Cambrian explosion is not true?
It includes a Snowball Earth and is characterized by mass extinctions
Which of the following is an advantage of sexual reproduction?
It increases genetic diversity
What does the cladistic method require?
It requires that character variation be identified as ancestral or derived
Why have plants been implicated in the Ordovician and Denonian glaciations, but not the Proterozoic glaciations?
Land plants had not yet evolved during the Proterozoic
Which approach is used to determine the probability that a proposed phylogenetic tree would give rise to observed data given an assumed rate of evolution?
Maximum likelihood
Archaea
Maybe found in environments that are extreme, including environments characterized by high temperatures, high pressure, or high salt.
Sexual reproduction allows greater genetic diversity through which of the following the processes?
Meiosis and crossing over
___________ involves isolating DNA from an environmental sample, sequencing it, and comparing it to known sequences in DNA databases
Metagenomics
Cold periods that led to glaciation and a drop in sea level during the last 2 million years created an opportunity for humans and other animals to
Migrate between once disconnected continents
The formation of Earth's ozone layer enabled of which of the following to occur?
Migration of living organisms from a watery to a terrestrial environment
__________ are the energy-producing organelles in eukaryotic cells
Mitochondria
Which of the following are characteristics of Eukaryotes? - Mitochondria - Physical separation of transcription and translation - Ability to be unicellular or multicellular - Lack of endomembrane system
Mitochondria, Physical separation of transcription and translation, and Ability to be unicellular or multicellular
Molecular Clock
Model that uses DNA comparisons to estimate the length of time that two species have been evolving independently
Which method is used to infer the timing of branching events by using the fossil record or geologic events to calculate DNA divergence rates?
Molecular clock
Which of the following statements about the origin of multicellularity are true?
Multicellularity has arisen independently in different eukaryotic groups
How does homoplasy arise in DNA sequences?
Mutation of the same nucleotide base occurs independently in two lineages
How does homoplasy arise in DNA sequence?
Mutation of the same nucleotide base occurs independently in two lineages.
Why is the rate of evolution more rapid in segments of DNA that have no function?
Natural selection does not affect these DNA sequences
What is it called when the capsid is tightly associated with the genome?
Nucleocapsid
Viruses are ______________ _______________ _____________
Obligate intracellular parasites
What is a character state
One of two or more variations of a character
Why are only shared derived, instead of all derived, characters useful in cladistics for reconstructing phylogenies?
Only shared derived characters indicate that two or more taxa are descended from an ancestor that was not an ancestor of taxa that don't possess the character state in question. Thus, taxa possessing the state are more closely related to each other than they are to taxa without the trait.
What principle proposes that the most likely phylogenetic tree is the one that is the simplest for all the characters and their states?
Parsimony
It has been discovered that enzyme-like catalysis can be carried out not only by enzymes but also by
RNA
Viroids are infectious disease agents in plants that are composed solely of circular ________
RNA
When constructing phylogenies, the assumptions of the principle of parsimony may be violated under what conditions?
Rapid evolution of characters
Hadean, Archean, Proterozoic
Referred to as the Precambrian
The Phanerozoic Eon
Represents only 12% of Earth's history, yet it contains most of the biological history of the diversification of multicellular life. Birds and mammals have existed for 4% of Earth's existence, whereas humans have existed for 0.2% of the history of Earth.
Bacillus
Rod shaped bacteria
Which form of reproduction allows greater genetic diversity?
Sexual
What kind of data were first used to create phylogenetic trees?
Similarities in morphology
What most accurately describes the evolution of different charcters?
Some characters evolve more rapidly than others.
Dome-shaped structures made of mats of cyanobacteria and trapped mineral deposits called __________________ can be found throughout the world; some are as old as 2.7 billion years.
Stromatolites
What does symplesiomorphies imply?
Symplesiomorphies reflect character states inherited from a distant ancestor, they don't imply that species exhibiting that state are closely related
_______ is the study of the evolutionary relationship among organisms
Systematic
What are CD4+ cells
T helper cells, that are crucial immune system cells
Which cell is the most important cell type infected by HIV?
T-helper cells
If we consider all frogs and toads together, we are including numerous genera and families at once. Which would be the appropriate term to use for this group of beings?
Taxon
Hadean Eon
The earliest period in Earth's history (4.5 to 4.0 billion years ago), the "hellish era," when the planet's formation was still ongoing and was unsuited to life.
Phylogeny
The evolutionary history of a species or group of related species (tree)
Marine organisms were able to evolve to colonize terrestrial environments for a variety of reasons including which of the following?
The formation of the ozone layer which protected life from UV radiation
Surface area of a cell or bacteria
The more surface area a cell has in proportion to the amount of volume the more rapidly it can take up nutrients
Phanerozoic Eon
The most recent eon, an interval of time from 542 Ma to the present.
Proterozoic Eon
The most recent of the Precambrian eons.
Phenotypically
The observable physical or biochemical characteristics of an organism, ad determined by both genetic makeup and environmental influences.
According to the principle of parsimony, among a series of proposed cladograms, which is the most likely?
The one with the fewest number of character changes
On a branching diagram, what does the joining of twigs and branches represent?
The pattern of common ancestry
In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located together on the same plasmid within a particular bacterium. If this bacterium readily performs conjugation involving a copy of this plasmid, then the result should be which of the following?
The rapid spread of tetracycline resistance to other bacteria in a favorable habitat
One of the major benefits of multicellularity is that it allows organisms to deal with their environments in novel ways through which of the following?
The specialization of cells into various types of tissues and organs
Systematic
The study of evolutionary relationships
Define microfossils
They are fossilized forms of microscopic life
What did Stanley L. Miller and Harold C. Urey do?
They attempted to reproduce the conditions in the Earth's primitive oceans under a reducing atmosphere, in order to solve the question of " What kind of organic molecules would be produced by natural processes?
Given that pathogenic prions can be passed from one organism to another to cause disease, what kind of information do they carry that results in the change in phenotype?
They contain the information required to cause normal prion proteins to fold incorrectly
What are viruses considered?
They have been found as obligate intracellular parasites in every kind of arganism that has been investigated for their presence.
Which of the following statements is true for all of the species that come after a branch point in a cladogram?
They will share at least one shared derived character
If a scientist found very high concentrations of organic biomarkers deep inside a 3.9 billion year old meteorite, how would this effect the explanation of the origins of life on Earth?
This would provide evidence for the extraterrestrial origin of life
True or false: Cells underwent the most evolutionary change when life was primarily aquatic.
True
True or false: Evidence indicates that the first cells were probably prokaryotic.
True
Multicellularity has arisen independently in different eukaryotic super-groups, true or false.
True (ex: red, brown, green algae)
Outside of a host cell, what are viral particles called?
Virions
Identify the disease agent that ranges in size from about 20-250 nm in diameter.
Virus
The disease that causes the development of numerous small cavities in the brain of infected individuals due to death of neurons producing a spongy appearance is called
_transmissible spongiform encephaopathy
Homoplasy
a character shared by a set of species but not present in their common ancestor
Outgroup
a group of organisms not belonging to the group whose evolutionary relationships are being investigated
Lytic cycle
a viral reproductive cycle in which copies of a virus are made within a host cell, which then bursts open, releasing new viruses
Lysogenic cycle
a viral reproductive cycle in which the viral DNA is added to the host cell's DNA and is copied along with the host cell's DNA. The integrated phage genome is called a prophage, and the cell containing a prophage is called a lysogen.
A(n) ________________ viral infection involves the rapid replication of the virus, often at the site of infection, which leads to sudden symptom onset.
acute
Among mammals, the presence of lungs is a(n)
ancestral character because it is present in other vertebrate animals and likely evolved prior to the common ancestor or mammals
Plesiomorphies
ancestral states
Prokaryotic organisms that are closely related to eukaryotes and are often found to inhabit extreme environments such as those with very high temperatures, high pressure, or high salt are ________
archae
Prokaryotic organisms that are closely related to eukaryotes and are often found to inhabit extreme environments such as those with very high temperatures, high pressure, or high salt are __________.
archea
Changes in the concentration of gases such as O2, N2, CO2, and CH4 in the ________________ have had important effects on the evolution of life on Earth.
atmosphere
The classification of viruses based on genome replication is known as the __________________ classification after the scientist that first proposed it
baltimore
Organic molecules which are clearly of biological origin are called __________
biomarkers
The use of microbes to break down harmful organic substances such as industrial waste is called ____________
bioremediation
The use of microorganisms to remove pollutants from water, air, and soil is called
bioremediation
A variant of a trait in cladistic analyses is known as a __________ state
character
In cladistics, a(n) ____________ is any aspect of the phenotype, including morphology, physiology, behavior, and DNA.
character
A ___________ is constructed by nesting clades characterized by shared derived characters.
cladogram
The type of diagram that represents hypothesized evolutionary relationships among taxa is called a __________
cladogram
The group that probably gave rise to chloroplasts is the
cyanobacteria
Chemical elements such as carbon, nitrogen, phosphorus, and sulfur are released from dead organisms back to the physical environment by prokaryotes and fungi that are called
decomposers
Stramenopile protists with double silicate shells are commonly called _______
diatoms
A(n) _________________ disease is a disease that appears in the population for the first time, or that spreads to a new geographical area.
emerging
Mitochondria and chloroplasts are both believed to have entered early eukaryotic cells by a process called __________
endosymbosis
Chemolithoautotrophs
energy from oxidizing inorganic substances
The domain that includes organisms that possess mitochondria, an endomembrane system that compartmentalizes certain organelles, and can be truly multicellular is called __________
eukaryote
True multicellularity is only found in the domain ___________
eukaryote
The action of the shifting continental plates of Earth has important effects on the course of ___________ of living organisms by re-productively isolating populations or allowing previously separated populations to interbreed.
evolution
Clade
evolutionary branch of a cladogram that includes a single ancestor and all its descendants
True or false: the role of bacteria and archaea in the cycling of carbon is very limited
false
Because there is no natural selection against mutations in regions of DNA that are nonfunctional, evolution in those regions occurs more ____________
frequently
Radiolarians secrete glassy exoskeleton made of silica. Those exoskeletons
give them distinct symmetrical shapes
Some prokaryotes are __________ which means they obtain some of their carbon from organic molecules. Typically, those organisms also obtain their energy from pre-made organic molecules, such as glucose.
heterotrophs
A ____________ is a shared character state that was not inherited from a common ancestor. These characters can make two species seem related when they are actually not
homoplasy
The transfer of genes between different species is known as _____________ gene transfer
horizontal
This _____________ gene transfer occurs when genes move from one cell to another by conjugation or by means of viruses (transduction).
horizontal
The cell or organism types that a particular virus can infect are referred to as its _________
host range
A scientist is studying endosymbiosis in cells. This means she is investigating
how mitochondria and chloroplasts were derived from prokaryotic cells
Ancestral
inherited from the most recent common ancestor of an entire group
Viruses are obligate _____________ parasites
intracellular
The first _____ on Earth may have arisen in hydrothermal deep sea vents, at the shore, or elsewhere in a smelly chemical ocean.
life
Phylogenies may be inferred using the maximum __________ statistical approach, which fits data to the phylogenetics model that best agrees with assumptions regarding the rate at which characters evolve.
likelihood
In order to study viruses in the environment, scientists isolate nucleic acids from an environmental sample, sequence them, and use computers to assemble genomes and compare them to known sequences in databases. This approach is known as _______.
metagenomics
This type of Staphylococcus aureus has been acquired in hospital settings for some time and is now being observed in community-acquired infections.
methicillin-resistant
Antibiotic-resistant strains of the bacterium Staphylococcus aureus that are often acquired in hospitals but are becoming more common outside of the hospital setting are called
methicillin-resistant Staphylococcus aureus
Two principal organelles in eukaryotes that were apparently derived from different types of bacteria are the
mitochondria and chloroplasts
A major advantage of __________ is that it enabls to specialize into tissues and organs having specific functions.
multicellularity
A major advantage of _____________ is that it enables cells to specialize into tissues and organs having specific functions
multicellularity
Derived
not inherited from the most recent common ancestor of the group and is shared only by a subset of the species
Infolding of the cellular membrane has led to the development of the
nuclear envelope
In cladistics, a(n) _____________ is a taxon that is closely related to, but not a member of, the group whose evolutionary relationships are being studied
outgroup
In ___________ viral infections, a virus or its genome can be found in the host for long periods of time: years, decades, and sometime for the rest of the host's life.
persistant
A change in the phenotype of a lysogenic bacterium caused by the prophage is called _______ ________
phage conversion
Prokaryotes may gain a selective advantage in their particular environments when _______ are transferred to them via conjugation.
plasmids
Prokaryotes may gain a selective advantage in their particular environments when _________ are transferred to them via conjugation
plasmids
Infectious proteins that can cause transmissible spongiform encephaopathies are called ________________
prions
Bacteria and archaea are collectively referred to as ________________
prokaryotes
The french microbiologist Louis Pasteur
refuted the idea of spontaneous generation
Symplesiomorphies
shared ancestral states
A character that is shared by two or more species because it originated in their most recent common ancestor is a _________________ character.
shared derived
Because it was inherited from the most recent common ancestor, hair in mammals is called a ________ -_______ character in cladistic analyses.
shared derived
Early systematics (before the advent of molecular sequencing) was based on overall __________ between species.
similarity
Spirillum
spiral shaped bacteria
Rodinia was a single __________ that existed during the Proterozoic eon.
supercontinent
Reverse Transcription
synthesis of DNA from an RNA template
Principle of parsimony
the belief that explanations of phenomena and events should remain simple until the simple explanations are no longer valid
Tuberculosis afflicts the respiratory system, thwarts the immune system, and is primarily transmitted in what way?
through the air
Within a multicellular host, many viruses also exhibit ________ ________, targeting only a specific subset of cells
tissue tropism
DNA can enter bacterial cells via _____________, a process that uses viral vectors.
transjuction
Chemolithoheterotrophs
use reduced inorganic molecules as their energy and electron source but derive their carbon from organic sources. (prokaryotes)
The pace of evolution is __________
variable
In sexually reproducing populations, traits can be transferred only ____________ from parent to child.
vertically
When outside of a host cell, an individual viral particle is known as a __________
virion
