Unit 1, Chapter 2: Diversity: From Simple to Complex Flashcards
The large mammals used in modern agriculture, including cattle and sheep, have digestive tracts that contain millions of methane-producing archaea. Each animal belches large quantities of methane every day. Explain how livestock farming might play a role in climate change, given that methane is a more potent greenhouse gas than carbon dioxide.
With large populations of livestock worldwide, there is an immense amount of methane released into the air each day. This is likely contributing to global warming and climate change.
Predict how conjugation could be an agent for increasing biodiversity among prokaryotic species that use it.
In conjugation, different amounts of DNA are exchanged between cells. The resulting cells are new genetic forms of the prokaryotes and represent an increase in biodiversity.
Which is a method scientists use to classify viruses?
Size and shape of the capsid.
Presence of absence of a cell wall.
Composition of cell membranes.
Way they obtain nutrition.
Composition of cell walls.
Size and shape of the capsid.
During the lytic cycle, what happens to a virus after it enters a host cell?
It forms a provirus.
It replicates.
It dies.
It becomes inactive.
It undergoes cell division.
It replicates.
Which statement about bacteria is true?
They cannot exchange DNA.
They occur in three main shapes: round, cubic, and spiral.
They are all heterotrophs.
They are eukaryotes.
They are commonly known as extermophiles.
They occur in three main shapes: round, cubic, and spiral.
Which best describes plasmids?
They are small components of plasma.
They are an important means of genetic recombination in prokaryotes.
They help amoebas to move and capture food.
They contain genes that are the same as those found in the chromosome.
Once they split from the bacterial chromosome, they cannot rejoin it.
They are an important means of genetic recombination in prokaryotes.
Which structures do some bacteria form when they are faced with unfavourable environmental conditions?
Capsids
Toxins
Chloroplasts
Endospores
Zygotes
Endospores
Which statement about diatoms is true?
They are heterotrophs.
They are prokaryotes.
They have two glagella.
They have rigid cell walls with an outer layer of silica.
They lack diversity and only occur in small numbers.
They have rigid cell walls with an outer layer of silica.
The structure and biochemistry of which two organelles support the hypothesis of endosymbiosis?
Cell Wall and Mitochondria
Chloroplasts and Golgi Body
Endoplasmic Reticulum and Cell Membrane
Mitochondria and Chloroplasts
Nucleus and Cytoplasm
Mitochondria and Chloroplasts
Which is an example of a plant-like protist?
- Balantidium*
- Entamoeba*
- Euglena*
- Paramecium*
- Plasmodium*
Euglena
State whether you agree or disagree with the following statement, and explain your reasoning: Protozoans are heterotrophic protists.
Agree. Protozoa are animal-like protists that consume other organisms.
Which are thought to be more closely related, a bacterium and an archaeon, or an apple tree and a great white sharke? Why?
The apple tree and the great white shark because they are in the same domain; the bacterium and archaeon are in different domains.
Why are disease-causing prokaryotes that form endospores more of a concern for human health than those that do not?
Because they can survive all sorts of harsh conditions that we might impose (like heat, drying out, or chemicals) and then can “germinate” back into active disease-causing bacteria.
Identify the shapes of the three types of bacteria shown in the photographs.
A - bacilli
B - spiral
C - coccus
How are mitochondria and chloroplasts distinct from other organelles?
They are bacteria-like, having a circular chromosome with bacteria-like genes; they reproduce inside the cell by binary fission; they have their own bacteria-like ribosomes for making their own proteins.
What are the three main groups of protists, based on their mode of obtaining nutrition.
Plant-like, fungus-like, and animal-like protists.
Compare sexual and asexual reproduction in diatoms. How do the end products differ genetically from one another?
Asexual reproduction will produce a clone that is genetically identical. Sexual reproduction involves an exchange of haploid nuclei that merge to form diploid individuals that are a new combination of genes from two individuals.
What is it about the way that euglenoids obtain nutrition that makes them unique as protists?
They eat and produce food through photosynthesis (autotrophic and heterotrophic).
White blood cells in humans are part of the immune system and engulf bacteria and act like independent, living, single-celled organisms. What protist does this remind you of, and what would you expect to be a major difference between them?
This mode of engulfing bacteria is like the action of amoeba. However, the human body creates the white blood cells, but the amoeba has its own chromosomes and it reproduces asexually.
What argument would you make in support of the idea that the first organisms on Earth were archaea?
Early conditions on Earth were likely very harsh—cold or hot, volcanic, UV light from the sun, perhaps acidic, etc.—and some archaeons can cope with extreme conditions very well.
If someone proposed that viruses were the ancestors of life on Earth, would you accecpt this idea? Why or why not?
No, because even though they are small and simple, they need cells for survival, so they probably came later.
All living things can be classified according to their anatomical and physiological characteristics. You discover an unusual organism growing in the damp leaf litter of an autumn forest. In the lab, you look at its cells under a microscope, and you see it is single-celled, is eukaryotic, and has chloroplasts. Can you place it in a kingdom? Explain you reasoning in detail.
Yes, it is a protist. It is not an archaeon or bacterium because it has eukaryotic cells. It is not an animal or a fungus because it has chloroplasts. It is not a plant because plants are multicellular.
Many humans with diabetes need regular injections of insulin. Imagine you could engineer a virus that is specialized. It can infect the cells of a lab animal so that the animal carries the human gene for making insulin in addition to its own genes. Why would this be an advantage?
This means that when the virus enters the cell, it has the gene to make human insulin, and the infected cell then produces insulin, which could be harvested for human injections.
Human activities affect the diversity of living things in ecosystems. By creating extreme environments, such as water or soil that contain high amounts of toxins or acid, are we encouraging the evolution of new archaea? What would be the positive and the negative consequences of this?
If the conditions we make are new, we may be encouraging evolution of new extremophiles. We should be careful about changing nature, but if the new organisms help contain the negative environmental consequences, that is a good result.
Which organism is a prokaryote?
amoeba
Euglena
green algae
cyanobacteria
paramecium
Cyanobacteria
What do Balantidium coli, a parasitic protist, and the most common cause of abcterial pneumonia, Streptococcus pneumoniae, have in common?
Both are prokaryotic cells.
Both contain DNA.
Both have membrane-bound organelles.
Both have a membrane-bound nucleus.
Both use mitosis and meiosis for cell division.
Both contain DNA.
Diseases such as bovine spongiform encephalopathy (BSE) and scrapie in sheep are caused by this group of disease-causing agents.
Prions
Viruses
Parasites
Bacteria
Fungi
Prions
Identify the most common shapes of bacteria and archaea.
Polyhedral, spherical, and cylindrical.
Gametic, zygotic, and sporic.
Spherical, rod, and spiral.
Animal-like, fungus-like, and plant-like.
Ciliated, flagellated, and amoebic.
Spherical, rod, and spiral.
Which is a key difference between archaea and bacteria?
Archaea are prokaryotic while bacteria are eukaryotic.
Archaea can live in anaerobic conditions while bacteria can only live in aerobic conditions.
Archaea can only live in less extreme condition, while bacteria can live in more extreme conditions.
Archaea do not use photosynthesis as a source of metabolic energy, while some bacteria can use photosynthesis as a source of metabolic energy.
Archaea have membrane-bound organelles while bacteria do not have membrane-bound organelles.
Archaea do not use photosynthesis as a source of metabolic energy, while some bacteria can use photosynthesis as a source of metabolic energy.
Staphylococcus, Streptococcus, and Enterococcus are bacteria that are stained dark blue or violet by Gram stain. Which statement about these organisms is false?
All are Gram-positive bacteria.
All are Gram-negative bacteria.
All are spherical bacteria.
All are prokaryotic cells.
All can cause diseases.
All are Gram-negative bacteria.
Which theory does the evidence listed below support?
- Membranes of the chloroplasts and mitochondria are similar to living prokaryotes.
- Ribosomes in chloroplasts and mitochondria are similar to ribosomes in prokaryotes.
- Mitochondria and chloroplasts reproduce by binary fission.
- Chloroplasts and mitochondria have a circular chromosome.
Endospore Theory
Endosymbiotic Theory
Theory that Archaea carry out photosynthesis.
Theory of how eukaryotes became multicellular.
Theory that viruses are cells.
Endosymbiotic Theory
Which group includes organisms that are parasites of fish, insects, and plants?
Sporozoans
Amoebas
Paramecia
Water Moulds
Flagellates
Water Moulds
Which group of protists has rigid cell walls made of silica?
Diatoms
Dinoflagellates
Euglenoids
Amoebas
Paramecia
Diatoms
Which group of protists has chloroplasts and conduct photosynthesis but is also heterotrophic?
Diatoms
Dinoflagellates
Euglenoids
Amoebas
Paramecia
Euglenoids
Like other organisms that usually reproduce asexually, diatoms sometimes reproduce sexually when conditions are poor. Why do you think organisms switch to sexual reproduction when conditions are poor?
Sexual reproduction increases diversity, which increases resilience.
Compare the function of a chloroplast to the function of a mitochondrion.
Chloroplasts perform photosynthesis, mitochondria perform cellular respiration.
Which group is currently classified in the kingdom Protista by some taxonomists and into the kingdom Plantae by others? Explain why there is so much confusion.
Algae—they are not true plants because they do not have embryos. They are not true protists because they are multicellular.
In most respects, the environment on Mars is very harsh. In winter, temperatures are as low as -100ºC. The atmosphere contain little oxygen, and without the benefit of a thick ozone layer the Martian surface is bombarded with ultraviolet (UV) radiation. Explain why scientists looking for life on Mars would also be interested in some species in the kingdom Archaea.
Archaea are able to live in extreme environments. They are extremophiles. Bacteria are mesophiles (need moderate environments).
In 1958, a science fiction/horror movie called The Blob was released. In the movie, a mysterious extraterrestrial organism that looks like a giant blob of jelly creeps over the ground engulfing food, including people, as it slides along! The blob gets larger as it continues to engulf food. Based on this information, infer which protist may have served as a model for this fictional organism, and explain your answer.
A cercozoid (amoeba). Same shape and method of locomotion (pseudopods).
Compare the feeding strategies and locomotion of an amoeba and a paramecium.
They are predators. Amoebas engulf their food. Paramecium “eat” by using their oral groove.
Summarize the theory of endosymbiosis as it relates to the evolution of eukaryotic cells.
Prokaryotic cells acted as hosts, which engulfed endosymbionts and the endosymbiont was not destroyed. The two organisms supported each other.
Individual bacterial cells may have plasmids with the genes that protect the bacterial cells from antibiotics. Explain how this trait may be passed on to other bacterial cells in the colony.
Two bacteria can join together via a cytoplasmic bridge. The plasmid can travel from one bacteria to the other. The recipient divides by binary fission and the plasmid is now in two bacteria.
Describe why many individuals infected by HIV can test positive for the virus but still remain healthy for many years.
HIV reproduces lysogenically. It hides in its host until it is triggered to reproduce lytically.
Define Archaeon (plural archaea)
An individual prokaryotic cell or a single species that is in the domain Archaea.
Define Bacillus (plural bacilli)
A micro-organism whose overall morphology is rod-shaped.
Define Bacterium (plural bacteria)
An individual prokaryotic cell or a single species that is in the domain Bacteria.
Define Binary Fission
The asexual form of reproduction used by most prokaryotes (and some eukaryotic organelles), in which a cell divides into two genetically identical cells (or organelles).
Define Capsid
The outer protein layer that surrounds the genetic material of a virus.
Define Cilium (plural cilia)
A short, hair-like projection that functions in cell movement and particle maniplulation when coordinated with other cilia.
Define Coccus (plural cocci)
A micro-organism whose overall morphology is spherical or nearly so.
Define Conjugation
A process in which there is a transfer of genetic material involving two cells.
Define Endospore
A dormant bacterial cell able to survive for long periods during extreme conditions.
Define Endosymbiont
A cell that is engulfed by another cell in endosymbiosis.
Define Endosymbiosis
The theory that explains how eukaryotic cells evolved from the symbiotic relationships between two or more prokaryotic cells.
Define Extremophile
An organism that lives in habitats characterized by extreme conditions.
Define Flagellum (plural flagella)
A long, hair-like projection extending from the cell membrane that propels the cell using a whip-like motion.
Define Gram Stain
A stain that seperates bacteria into two major divisions (Gram positive and Gram negative) based on the cell wall’s response to the stain.
Define Host Cell
A cell that engulfs another cell in endosymbiosis.
Define Lysogenic Cycle
The replication process in viruses, in which the viral DNA enters the host cell’s chromosomes; it may remain dormant and later activate and instruct the host cell to produce more viruses.
Define Lytic Cycle
The replication process in viruses in which the virus’s genetic material uses the copying machinery of the host cell to make new viruses.
Define Mesophile
An organism that lives in habitats characterized by moderate conditions.
Define Methanogenesis
A biological (or chemical) process that produces methane as a by-product.
Define Parasite
An organism that benefits by living in or on another organism at the expense of that organism.
Define Prion
An infectious particle that causes damage to nerve cells in the brain, and that appears to consist mostly or entirely of a single protein.
Define Protist
A eukaryotic organism, usually unicellular, that is not a fungus, plant, or animal.
Define Provirus
Viral DNA that has become part of a host cell’s chromosome; can invade a cell, but does not kill it.
Define Pseudopod (plural pseudopodia)
A temporary cytoplasmic extension that amoebas use for feeding and movement.
Define Red Tide
A coastal phenomenon in which dinoflagellates that contain red pigments are so concentrated that the seawater has a distinct red colour.
Define Replication
The fundamental process of all cells, in which the genetic material is copied before the cell reproduces.
Define Virus
A structure that contains strands of DNA or RNA surrounded by a protective protein coat; it cannot live independently outside of cells.
What is an individual prokaryotic cell or a single species that is in the domain Archaea known as?
Archaeon (plural archaea)
What is A micro-organism whose overall morphology is rod-shaped known as?
Bacillus (plural bacilli)
What is n individual prokaryotic cell or a single species that is in the domain Bacteria known as?
Bacterium (plural bacteria)
What is the asexual form of reproduction used by most prokaryotes (and some eukaryotic organelles), in which a cell divides into two genetically identical cells (or organelles) known as?
Binary Fission
What is the outer protein layer that surrounds the genetic material of a virus known as?
Capsid
What is a short, hair-like projection that functions in cell movement and particle maniplulation when coordinated with other cilia know as?
Cilium (plural cilia)
What is a micro-organism whose overall morphology is spherical or nearly so known as?
Coccus (plural cocci)
What is a process in which there is a transfer of genetic material involving two cells known as?
Conjugation
What is a dormant bacterial cell able to survive for long periods during extreme conditions known as?
Endospore
What is a cell that is engulfed by another cell in endosymbiosis known as?
Endosymbiont
What is the theory that explains how eukaryotic cells evolved from the symbiotic relationships between two or more prokaryotic cells known as?
Endosymbiosis
What is an organism that lives in habitats characterized by extreme conditions known as?
Extremophile
What is a long, hair-like projection extending from the cell membrane that propels the cell using a whip-like motion known as?
Flagellum (plural flagella)
What is a stain that seperates bacteria into two major divisions (Gram positive and Gram negative) based on the cell wall’s response to the stain known as?
Gram Stain
What is a cell that engulfs another cell in endosymbiosis known as?
Host Cell
What is the replication process in viruses, in which the viral DNA enters the host cell’s chromosomes, where it may remain dormant and later activate and instruct the host cell to produce more viruses known as?
Lysogenic Cycle
What is the replication process in viruses in which the virus’s genetic material uses the copying machinery of the host cell to make new viruses known as?
Lytic Cycle
What is an organism that lives in habitats characterized by moderate conditions known as?
Mesophile
What sexual life cycle is pictured below?
Gametic
What sexual life cycle is pictured below?
Zygotic Sexual Life Cycle
What sexual life cycle is pictured below?
Sporic Sexual Life Cycle
Which term best describes the morphology of the bacteria shown in the picture?
Diploid
Bacillus
Coccus
Spiral
Pyramidal
Coccus
The picture shows one of the most common forms of bacteria and archaea called:
Cocci
Bacilli
Cubic
Spiral
Pyramidal
Bacilli
Classify the organism in the image.
Animal-Like Protist
Slime Mould
Plant-Like Protist
Fungus-Like Protist
Not enough information to tell.
Animal-Like Protist
Which group of protists do the organisms in the diagram belong to?
Animal-Like
Plant-Like
Fungus-Like
There is not enough information to tell.
There is one of each group in the image.
Plant-Like
Incubation time is the time for a symptom of a disease to occur after exposure. Consider the data on the incubation time of different viral diseases in the table below. Use the data to predict which diseases are cause by viruses that undergo the lytic cycle and which are caused by viruses that undergo the lysogenic cycle. What is a possible public health consequence of the incubation time for diseases caused by proviruses.
Lytic cycle: cold, possibly measles
Lysogenic cycle: shingles, warts, HIV
People do not realize they are infected and do not take any precautions to prevent the spread of the disease to others.
Mentally make a table that identifies and describes the three common shapes for bacteria and archaea. Imagine an example organism for each shape.
The image shows the cross sections of two cell walls. Based on what you know about the Gram stain, which do you think is the cell wall of a Gram-positive bacterium and which is that of the Gram-negative one? Why?
The Gram-positive bacterium is the one with the thick cell protein layer that has stained purple; the Gram-negative bacterium has a thin protein layer that stained pink.
Use a flowchart to show the sequence of the steps involved in conjugation.
The images below show a bacterial cell dividing into two cells. The sequence of cell division is incorrect. Redraw the illustrations in the correct sequence, and explain what is happening at each step.
Refer to the figure below. Identify whether the life cycle of the organism described below is asexual or sexual. For those that you have identified as sexual life cycles, determine if they are gametic, zygotic or sporic.
Sea lettuce (Ulva) has two life stages. In stage 1, a zygote undergoes meiosis and releases swimming haploid spores. The spores grow into male and female haploid organisms. In stage 2, the haploid organisms undergo mitosis to produce mobile male and female gametes. The gametes fuse together and swim to the bottom, where they grow into the zygote once more.
Sexual, Zygotic
Refer to the figure below. Identify whether the life cycle of the organism described below is asexual or sexual. For those that you have identified as sexual life cycles, determine if they are gametic, zygotic or sporic.
Plants have a diploid stage, in which cells undergoing meiosis produce haploid reproductive cells called spores. The spores develop into haploid organisms that produce haploid gametes by mitosis. The gametes unite to produce a diploid stage organism, thus completing the cycle.
Sexual, Sporic
Refer to the figure below. Identify whether the life cycle of the organism described below is asexual or sexual. For those that you have identified as sexual life cycles, determine if they are gametic, zygotic or sporic.
A fertilized egg of a fish is called a zygote. The diploid zygote uses mitosis to develop into an adult diploid organism. Specialized cells in the reproductive organs of the adults undergo meiosis to create haploid gametes. When the adult fish spawn, the sperm from the male fertilize the eggs released by the female to form the diploid zygote.
Sexual, Gametic
Study the drawings below. Identify the phylum to which each organism belongs. Explain how you decided where each organism belongs.
A) Euglenoid - has chloroplasts and an eyespot
B) Cercozoan - has pseudopods
C) Flagellate - has two flagella
D) Ciliate - has cilia
