Overview of the Tree of Life and Evolution
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Questions and Answers

Which of the following correctly indicates the genus and species name for a lion?

  • Felidae, Carnivora
  • Panthera, leo (correct)
  • Carnivora, Panthera
  • Mammalia, Panthera

What is the highest taxonomic rank in the Linnaean hierarchy?

  • Class
  • Kingdom
  • Phylum
  • Domain (correct)

What role does phylogenetics play in the study of organisms?

  • It focuses on the geographic distribution of organisms.
  • It determines the diet of different species.
  • It classifies organisms based on physical characteristics.
  • It analyzes the evolutionary history and relationships among organisms. (correct)

Which of the following statements about taxonomy is true?

<p>Taxonomic units at any level are called taxa. (C)</p> Signup and view all the answers

How can DNA sequences be utilized in phylogenetic analyses?

<p>They allow comparison of present-day species to a common ancestor. (C)</p> Signup and view all the answers

What is the primary role of rRNA in cells?

<p>It forms part of the ribosome essential for translation. (C)</p> Signup and view all the answers

Which statement correctly describes the phylogenetic tree?

<p>It shows the evolutionary relationships and patterns of descent. (A)</p> Signup and view all the answers

How do mutations contribute to evolution?

<p>They accumulate over time, driving variation. (A)</p> Signup and view all the answers

What does it mean when two taxa are described as sister taxa?

<p>They share an immediate common ancestor not shared by any other group. (B)</p> Signup and view all the answers

What limitation is associated with the use of rRNA gene sequences in phylogenetic analyses?

<p>They cannot tolerate large mutations and mutate slowly. (C)</p> Signup and view all the answers

Which of the following Plasmodium species does NOT cause malaria?

<p>Plasmodium asexualis (B)</p> Signup and view all the answers

What is the role of the female Anopheles mosquito in the life cycle of Plasmodium?

<p>It transmits the infective sporozoites to humans. (B)</p> Signup and view all the answers

Which stage of Plasmodium is considered the infective form?

<p>Sporozoite (D)</p> Signup and view all the answers

What percentage of the annual malaria infections are estimated to occur in Africa?

<p>Roughly 90% (C)</p> Signup and view all the answers

Which characteristic is NOT typically associated with viruses?

<p>Have complex life cycles (D)</p> Signup and view all the answers

What is the size range of a rhinovirus?

<p>30 nm - 800 nm (B)</p> Signup and view all the answers

What allows some bacteria to endure extreme conditions for extended periods?

<p>Formation of endospores (C)</p> Signup and view all the answers

Which virus is known as the largest virus infecting amoeba?

<p>Pandoravirus (A)</p> Signup and view all the answers

Which statement about bacterial growth phases is true?

<p>In the stationary phase, bacterial growth ceases. (C)</p> Signup and view all the answers

Which of the following components protects the viral genome?

<p>Protein coat (B)</p> Signup and view all the answers

What is a characteristic of aerobic bacteria?

<p>They require oxygen for metabolism. (B)</p> Signup and view all the answers

Which form of photosynthesis do purple and green sulphur bacteria perform?

<p>Anoxygenic photosynthesis (D)</p> Signup and view all the answers

What is the estimated number of bacterial cells present in the human body?

<p>~10^13-10^14 bacteria (C)</p> Signup and view all the answers

Which of the following is NOT a stage of the plague caused by Yersinia pestis?

<p>Chirpy plague (C)</p> Signup and view all the answers

What distinguishes obligate anaerobes from facultative anaerobes?

<p>Obligate anaerobes cannot survive in the presence of oxygen. (A)</p> Signup and view all the answers

What is one reason bacteria are considered an important reservoir of nutrients?

<p>They play a role in nutrient cycles. (A)</p> Signup and view all the answers

What structural category does the Tobacco mosaic virus belong to?

<p>Helical (B)</p> Signup and view all the answers

Which of the following describes the Norovirus’s genome?

<p>Single stranded positive RNA (B)</p> Signup and view all the answers

What is the function of reverse transcriptase in retroviruses?

<p>Converts RNA into DNA (C)</p> Signup and view all the answers

What type of viral structure is characterized by a head that is an icosahedron and a tail that is helical?

<p>Complex (D)</p> Signup and view all the answers

How do enveloped viruses, such as HIV, acquire their envelopes?

<p>From the host cell's plasma membrane during budding (D)</p> Signup and view all the answers

In the context of viral genomes, what does a (+) strand RNA signify?

<p>It can be translated directly into protein (C)</p> Signup and view all the answers

What characterizes pleomorphic viruses?

<p>They can exist in various forms and often exhibit branched structures. (C)</p> Signup and view all the answers

What is the main distinguishing feature of viruses compared to living organisms?

<p>They replicate exclusively within host cells. (D)</p> Signup and view all the answers

What is the primary characteristic that distinguishes the cell wall composition of Archaea from that of bacteria?

<p>Archaea do not contain peptidoglycan in their cell walls. (D)</p> Signup and view all the answers

Which of the following archaeal genera is known to possess a completely S-layer based cell wall?

<p>Methanocaldococcus jannaschii (C)</p> Signup and view all the answers

What structural characteristic differentiates archaeal lipids from those found in bacterial and eukaryotic membranes?

<p>Archaeal lipids use ether linkages to bond the lipid tail to glycerol. (C)</p> Signup and view all the answers

Which trait is NOT typical of the archaeal cell membrane structure?

<p>Presence of peptidoglycan. (A)</p> Signup and view all the answers

What is the primary function of hami in Archaea?

<p>Biofilm formation and attachment. (A)</p> Signup and view all the answers

What distinguishes archaeal flagella from bacterial flagella?

<p>Archaeal flagella rotate to drive motility. (C)</p> Signup and view all the answers

What is a common method of reproduction observed in many Archaea?

<p>Binary fission resulting in genetically identical daughter cells. (D)</p> Signup and view all the answers

Which characteristic is a notable feature of Methanobrevibacter ruminantium?

<p>It possesses pseudomurein in its cell wall. (A)</p> Signup and view all the answers

Flashcards

Linnaean Taxonomy

A system for classifying organisms based on shared characteristics.

Binomial Nomenclature

Two-part naming system for species (Genus species).

Phylogenetic Tree

A diagram showing evolutionary relationships among organisms.

Phylogenetic Analysis

Method of determining evolutionary relationships by comparing DNA.

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Taxon

A taxonomic unit (e.g., species, genus, family) at any level of classification.

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Phylogenetic analysis using rRNA genes

Using rRNA gene sequences to build evolutionary relationships (family trees) among organisms.

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Sister taxa

Groups of organisms that share an immediate common ancestor.

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Horizontal gene transfer

Transfer of genetic material between unrelated organisms.

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Metagenomics

Study of genetic material directly from environmental samples, such as seawater.

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What is the stationary phase of bacterial growth?

A phase where bacterial growth ceases, due to factors like nutrient limitation or waste buildup.

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How are bacteria classified by their oxygen needs?

Bacteria can be classified as aerobic (require oxygen), anaerobic (don't need oxygen), or facultative anaerobes (can survive with or without oxygen).

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What is 'oxygenic' photosynthesis?

Photosynthesis that releases oxygen as a byproduct. Example: Cyanobacteria.

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What is 'anoxygenic' photosynthesis?

Photosynthesis that does not produce oxygen. Example: Purple/green sulfur bacteria.

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What are bacterial endospores?

Dormant, highly resistant structures formed by some bacteria to survive harsh conditions like heat, chemicals, and radiation.

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Why are bacteria important for nutrient cycles?

Bacteria play a crucial role in breaking down organic matter, recycling nutrients like carbon, nitrogen, and phosphorus, essential for ecosystems.

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What is the human microbiome?

The vast collection of bacteria, fungi, and other microbes that live in and on the human body.

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How does the Plague spread?

The Plague is a zoonotic disease usually spread through infected fleas that live on rodents.

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What are the common cell wall types in Archaea?

Archaea cell walls can be composed of polysaccharides, proteins, glycoproteins, or a mixture of these macromolecules. Some Archaea may even lack a cell wall.

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What makes Pseudomurein different from Peptidoglycan?

Pseudomurein, a component in some Archaeal cell walls, is structurally similar to peptidoglycan but has a few important differences. Its amino sugar backbone is composed of L-isomers, and it is not affected by penicillin.

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What is the most common cell wall component in Archaea?

The S-layer is the most common cell wall type found in Archaea. It is composed of protein or glycoprotein and has a crystalline structure.

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How are Archaeal cell membrane lipids unique?

Archaeal cell membranes have unique lipids. Their tails are not fatty acids and have a different structure. The linkage between the lipid tail and glycerol is also different.

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What are the two unique structures archaeal cell membranes can form?

Archaeal cell membranes can form two unique structures: a bi-layer and a mono-layer. These differences in structure give them unique properties.

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What are Hami?

Hami are pili-like structures found on some Archaea. They are shaped like grappling hooks and help with attachment to surfaces.

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What are Archaella?

Archaella are unique flagella found in some Archaea. They are smaller than bacterial flagella and use ATP to rotate for motility.

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How do most Archaea reproduce?

Most Archaea reproduce asexually by binary fission. In this process, a parent cell divides into two genetically identical daughter cells.

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What causes malaria?

Malaria is caused by parasitic protists belonging to the genus Plasmodium. These protists infect humans and are transmitted through the bite of infected female Anopheles mosquitoes.

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How many Plasmodium species cause malaria?

There are four main species of Plasmodium that cause malaria: Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, and Plasmodium ovale.

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What is the vector for malaria?

The female Anopheles mosquito acts as the vector for malaria, transmitting the Plasmodium sporozoites to humans through its bite.

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What happens when a mosquito transmits sporozoites?

Once sporozoites enter a human through a mosquito bite, they travel to the liver cells where they multiply asexually, producing merozoites.

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What happens after merozoites are produced?

Merozoites are released from the liver cells and infect red blood cells, where they mature into trophozoites. Trophozoites multiply asexually, causing the bursting of red blood cells and the release of more merozoites, leading to cyclical fever.

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What are the types of forms Plasmodium takes in its life cycle?

Plasmodium has different forms during its life cycle: sporozoites, merozoites, and trophozoites. Sporozoites are the infective stage, merozoites are the vegetative stage, and trophozoites are the mature stage inside red blood cells.

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What are viruses?

Viruses are non-living entities that consist of a genome (DNA or RNA) enclosed in a protein coat, and sometimes a lipid envelope. They are obligate intracellular parasites, meaning they can only replicate inside a living host cell.

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How diverse are viruses?

Viruses infect all living things, from bacteria to humans, and are incredibly diverse in size, structure, and host range. They are the most abundant biological entities on Earth.

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What are the key components of a virus?

Viruses consist of a genetic material (DNA or RNA) enclosed within a protein coat called a capsid. Some viruses may also have an envelope, a lipid membrane surrounding the capsid.

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What are the different shapes of viruses?

Viruses come in various shapes, including helical (rod-like), icosahedral (ball-shaped), complex (with more complex structures), and pleomorphic (with variable shapes).

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How do viruses acquire envelopes?

Enveloped viruses acquire their envelopes by budding from the host cell's plasma membrane, taking a piece of the membrane with them.

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What are viral genomes?

Viruses can have different types of genetic material, including DNA or RNA. They can be single-stranded or double-stranded, and linear or circular.

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What is a reverse transcriptase?

Reverse transcriptase is an enzyme found in retroviruses that converts RNA into DNA.

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What is the difference between (+) and (-) RNA viruses?

Positive (+) strand RNA can be directly translated into protein by the ribosome. Negative (-) strand RNA must be copied into (+) strand first.

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What type of virus is HIV?

HIV is a retrovirus, meaning it has a single-stranded RNA genome that is reverse transcribed into DNA.

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Study Notes

Overview of the Tree of Life

  • Life has three domains: Bacteria, Archaea, and Eukarya
  • Microorganisms are the dominant form of life
  • Multicellular life evolved from single-celled organisms
  • Classification is done using Linnaean classification and phylogenetic analysis

Macroorganisms

  • Bacteria are a major group of microorganisms
  • Protists (Paramecium), fungi (Aspergillus), are other examples of macroscopic organisms
  • Organisms are classified based on shared characteristics
  • Binomial nomenclature provides two-part scientific names for each species (e.g., Panthera pardus)

Cellular Principles of Life

  • All cellular life evolved from a common ancestor
  • Genetic information is encoded in DNA
  • DNA is transcribed into RNA
  • RNA is translated into protein via ribosomes
  • Evolution involves changes in blueprints over time, driving biodiversity

Evolution

  • Evolution is the process of change that results in new species
  • All life shares a common ancestor (LUCA)
  • Life evolved into three domains

Time Scale of Life

  • Life originated ~ 3.8 billion years ago
  • Microbial life on earth existed until about 1 billion years ago

Life on Earth

  • Earth formed ~ 4.6 billion years ago
  • The first prokaryotes arose ~ 3.8 billion years ago
  • Life was exclusively microbial until about a billion years ago
  • Classification of organisms was made using Linnaean taxonomy
  • Organisms were classified based on observable characterstics
  • The linnaean system used names like species and order for classification

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Description

Explore the fascinating concepts of the Tree of Life, including the three domains of life: Bacteria, Archaea, and Eukarya. This quiz covers key principles of cellular life, the process of evolution, and the classification of organisms through Linnaean taxonomy and binomial nomenclature.

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