mt1 Flashcards
Describe the basic requirements for life and justify their role in supporting life.
-Water
-biogenic elements
-Dna
-energy source
Evaluate the characteristics of living organisms and identify those that are shared by living organisms only.
-Cellular organization: All living things are made up of cells.
-Metabolism: Chemical reactions that provide energy for cellular functions.
-Homeostasis: Ability to maintain stable internal conditions.
-Growth and development: Increase in size and complexity over time.
-Reproduction: Ability to produce offspring.
Response to stimuli: Reacting to environmental changes.
-Evolution: Genetic changes over generations to adapt to the environment.
Use the characteristics of living organisms to evaluate if viruses should be considered living or not.
Viruses do not meet most of the criteria for life, except for reproduction (inside a host) and evolution. Since they lack cells, metabolism, and independent reproduction, most scientists do not classify viruses as living organisms.
Describe the basic components that make up a virus.
-genome (DNA)
-Capsule
-envelope
-proteins
Explain why antibiotics do not affect viruses.
-viruses have no cell wall
-antibiotics are bacteria killas
Explain why a cellular membrane is required for living organisms to carry out many of their functions.
-The membrane controls what enters and exits the cell (homeostasis)
–transports water and nutrients
-prevents harm entering cell
Explain what a taxon is.
A group of organisms classified based on shared characteristics.
Explain the difference between monophyletic and paraphyletic organismal groups.
-Monophyletic groups represent a complete evolutionary lineage and are used in modern classification.
-Paraphyletic groups exclude some descendants and do not fully reflect evolutionary history.
Explain what convergent evolution is and how it relates to analogous structures.
-Convergent evolution occurs when unrelated organisms evolve similar traits due to similar environmental pressures or ecological roles.
Differentiate between analogous and homologous structures and give examples of each.
-Homologous structures show common ancestry and divergent evolution.
-Analogous structures result from convergent evolution, where different organisms develop similar adaptations to similar environments.
Explain how organic molecules such as amino acids and nucleic acids may have formed on Earth about 4 billion years
ago.
-Likely formed with small common molecules such as CH4, H2O, NH3 and H2.
-Mixture of gases in a lightning strike created amino acids.
Explain why the formation of cell membranes and the protocells were essential for life to occur.
-The cell membrane is built up by phospholipids that have polar and non-polar heads.
-Phospholipids may have formed the first protocell.
Explain the role RNA (ribonucleic acid) may have played in the early steps leading to life on Earth.
RNA likely self duplicated and made DNA.
Describe the likely habitat and energy source of LUCA.
likely near hydrothermal vent marine environments. Archeans ate up yummy inorganic chemicals.
Explain THREE characteristics of early prokaryotes.
- Lack of a Nucleus and Membrane-Bound Organelles
- Anaerobic Metabolism (Lived Without Oxygen)
- High Genetic Diversity and Rapid Reproduction
Describe what all prokaryotes have in common.
-Lack of nucleus and membrane-bound organelles
-have cell wall
-use horizontal gene transfer to create genetic variation
Describe how bacteria and archaea differ
-Many archaea are extremophiles while bacteria have many diverse environments.
-Bacteria have peptidoglycan, archaea do not.
-Bacteria: Ester linked
-Archaea: Ether linked
Explain the importance of differentiating between gram-positive and gram-negative bacteria.
Can help choose the right antibiotic during treatment.
Differentiate between transformation, transduction and conjugation. (HGT).
Transformation: The process by which bacteria take up free DNA from their environment.
Transduction: The transfer of bacterial DNA from one cell to another via a virus (bacteriophage).
Conjugation: The direct transfer of DNA between bacteria through a pilus
Describe several mechanisms that allow extremophiles to cope in extreme
conditions.
-Their membranes can withstand the heat or cold due to their ether linked membrane.
-They have salt and acid resistant proteins.
Describe the habitats where chemoautotrophs thrive and give several examples.
-Deep sea hydrothermal vents
-Acidic mines and sulfur springs
Describe what caused the “oxygen revolution”.
-Evolution of cyanobacteria is the main contributor to the oxygen evolution because they developed oxygenic photosynthesis.
Explain the role of prokaryotes in the carbon and nitrogen cycle.
-They have a unique ability to fixate carbon and nitrogen
-specifically in photosynthesis CO2 is taken and organic compounds are released.
-same goes for nitrogen,
-NH₄⁺ → NO₂⁻ → NO₃⁻
Explain why photoheterotrophs such as halobacteria are able to use light as an
energy source.
-Bacteriorhodopsin absorbs light
Compare and contrast different modes of metabolism in prokaryotes.
-Photoautotrophs: takes Light, carbon source is CO₂ (fixes carbon)
-Photoheterotrophs: takes Light carbon source is Organic Compounds
-Chemoautotrophs: takes Inorganic Molecules (H₂, Fe²⁺, NH₃), carbon source is CO₂ (fixes carbon).
-Chemoheterotrophs (us): takes in Organic Molecules carbon source is Organic Compounds.
Which of the statements below is correct regarding the staining of gram-negative and gram-positive bacteria?
A. Gram-negative bacteria stain purple because of their thick
peptidoglycan cell wall.
B. Gram-positive bacteria stain purple because of their thick
peptidoglycan cell wall.
C. Gram-positive bacteria stain pink because of their thin
peptidoglycan cell wall.
D. Gram-negative bacteria stain pink because of their thick
peptidoglycan cell wall.
B. Gram-positive bacteria stain purple because of their thick peptidoglycan cell wall.
Explain which environmental change that may have promoted the evolution of eukaryotes.
-The Oxygen Increase Led to Eukaryotic Evolution
-Endosymbiosis: The Origin of Mitochondria
Explain what symbiogenesis is and how it likely led to the evolution of eukaryotes.
-eukaryotic cells evolved through a symbiotic relationship between different prokaryotic cells.
- A Larger Prokaryote Engulfed a Smaller one and the mitochondria was born.
Evaluate the advantages and disadvantages of sexual reproduction and explain why sexual reproduction is common in
eukaryotes.
-Increases Genetic Diversity
-Improves Disease Resistance
-Eliminates Harmful Mutations
-Requires More Energy and Time
-Slower Reproductive Rate
-Risk of Unsuccessful Mating
What is NOT correct about the difference between eukaryotes and prokaryotes?
A. Eukaryotic cells have membrane-bound organelles, while
prokaryotic cells don’t.
B. Most eukaryotes can reproduce sexually, while prokaryotes
can’t.
C. All eukaryotic organisms are multicellular, while most
prokaryotes are not.
D. Prokaryotes can live in a wider variety of environments than
eukaryotes.
C. All eukaryotic organisms are multicellular, while most prokaryotes are not.
Describe the characteristics that all protists have in common.
-nucleus
-mitochondria
-mostly unicellular
Describe the evidence supporting the origin of chloroplasts in
photosynthesizing eukaryotes.
-Chloroplasts evolved from free-living cyanobacteria that were engulfed by an ancestral eukaryotic cell. Over time, this symbiotic relationship became permanent
Give an example of a protist from each eukaryotic supergroup.
Excavata: Giardia intestinalis
Chromalveolata: paramecium
Rhizaria: radiolarians
Archaeplastida: Chlorophytes
(green algae)
Amoebozoa: Gymnamoebas
Opisthokonta: Choanoflagellates
Explain the advantages of multicellularity.
-Different cells can be specialized to do different tasks
-increase in size
-longer lifespan
-complex communication and coordination
Describe how some protists are adapted to surviving harsh environmental
conditions.
-Dormant structures that resist desiccation
-Dormant structures like a cyst can survive unfavorable conditions such as dehydration
Describe the characteristics shared by all fungi.
-Cell walls made of chitin
-All sessile
-Eukaryotic cells
-Heterotrophic
Explain what extracellular digestion is and how it this process relates to
fungi.
-Fungi rely entirely on extracellular digestion for nutrient acquisition. They do not ingest food like animals; instead, they secrete enzymes into their surroundings to decompose organic matter.
Describe one difference and one similarity between plants and fungi.
-They are similar as they both have eukaryotic cells.
-They are different as they obtain nutrition differently.
Distinguish between monokaryotic and dikaryotic hyphae.
Number of Nuclei: Monokaryotic cells have one nucleus, while dikaryotic cells have two.
Explain how sexual reproduction in fungi differ from sexual reproduction in plants and animals.
-While plants reproduce sexually by means of seeds, fungi reproduce sexually or asexually through microscopic, unicellular spores, often dispersed by the wind or animals
Explain the difference between a parasite, a mutualist and a saprotroph.
Parasite: an organism that lives on or inside another organism (the host)
Mutualist: A mutualist is an organism that forms a mutually beneficial relationship with another organism, where both parties gain something of value from the relationship.
Saprotroph: A saprotroph is an organism that feeds on decaying organic matter
Explain how fungi facilitated early plants on land.
They formed symbiotic relationships with the root of plants. An example being Mycorrhizal fungi.
Describe how protists are able to carry out complex functions despite being unicellular.
Their metabolic flexibility, ability to form symbiotic relationships. They also have eukaryotic organelles.
Describe the energy source and carbon source for autotrophs, heterotrophs, phototrophs, and chemotrophs.
Autotrophs: Inorganic carbon (CO₂)
Heterotrophs: Organic carbon (from other organisms)
Phototrophs: can be CO₂ or organic molecules
Chemotrophs: can be CO₂ or organic molecules
Describe the byproducts of photoautotrophs and
chemoheterotrophs.
Phototrophs: Oxygen
Chemoheterotrophs: Carbon Dioxide
Which polysaccharide is usually found in the cell wall of fungi?
Glycogen
Which protist is believed to have evolved following a secondary endosymbiosis?
Brown algae
Which fungal phylum is considered the most primitive based on its simple reproductive structures?
Chytridiomycota
How do many protists achieve complexity without multicellularity?
Through unique cell shapes and organelle function.
What evidence suggests that fungi evolved from an aquatic ancestor?
Presence of flagellated spores in chytrids.
Which type of prokaryotes contribute to both the carbon and nitrogen cycles?
Decomposers, cyanobacteria, and archea.
A fungal species reproduces primarily through conidia. What can be inferred about this fungus?
It relies mostly on asexual reproduction.
Asexually reproducing fungi are HAPLOID or DIPLOID throughout their entire lifecycle!
haploid
What is a major function of the coelom (body cavity) in animals?
It serves as a hydrostatic skeleton for support and movement.
what are some differences between charophytes and chlorophytes?
-Chlorophytes mostly simple and unicellular.
-Charophytes are mostly complex and multicellular.
Which environmental conditions did plants have to adapt to in order
to thrive on land?
Water Loss & Desiccation
Support Against Gravity –
Nutrient & Water Uptake –
All bilateral animals contain diploblast or triploblasts?
Triploblasts
Bilateral animals with a true coelom are classified as either protostomes or deuterostomes based on their patterns of embryonic development. T or F?
True
What is cephalization?
Cephalization = Development of a head
Which of the following traits are present in red algae, but not in green algae?
-Phycoerythrin pigment for photosynthesis
-Cell walls
-Chlorophyll a
-Flagellated sperms
Phycoerythrin pigment for photosynthesis
Protostome means “mouth _______”,
Deuterostome means mouth _______
protostome: mouth first
Deuterostome: mouth second
