1When did life on the planet develop?
3.5 billion years ago
2We said that Cyanobacteria became chloroplasts. What is this theory called?
Endosymbiotic Theory
3The Earth is around 4.6 billion years old, whereas the _______ cell type is approximately 3.5 billion years old. Oxygen from _______ was created in large quantities approximately _______ years ago.
Prokaryotic; Photosynthesis; Approximately 2.4 billion years ago
4I said your body is covered with and contains "important microbes." How many did I say were present?
More than the number of cells that make you
5The size of the typical bacterium is cool! They are around _______ in size.
1 µm
6Relatively speaking, _______ cells are smaller than _______ cells.
Prokaryotic – eukaryotic
7Cells of Archaea lack _______ that most bacteria have.
Peptidoglycan
8Photosynthetic autotrophs use _______ as an energy source and _______ as a carbon source.
Sunlight; CO₂
9Photoautotrophs like Cyanobacteria use _______ as an electron source and _______ as an energy source.
H₂O; Sunlight
10DNA has individual "regions" or units coding for traits called
Genes
11The A's, T's, G's, and C's of a DNA molecule represent the
Nucleotides
13Define Ectomycorrhizae
Ectomycorrhizae are a type of mycorrhizal association where the fungus forms a sheath around the roots of a plant, enhancing water and nutrient absorption.
14Define Mycelium
Mycelium is the vegetative part of a fungus, consisting of a network of fine white filaments called hyphae.
15In nature, fungi typically play three ecological roles. Name and describe one ecological role fungi have in the environment. How is this role important?
Decomposition: Fungi break down dead organic matter, recycling nutrients back into the ecosystem, which is essential for soil fertility and plant growth.
16Give one actual example of a Latin binomial (name) of an organism.
*Homo sapiens*, *Escherichia coli*, *Arabidopsis thaliana*
17Name a plant disease caused by bacteria.
Fire blight caused by *Erwinia amylovora*
18Name one human disease caused by soil bacteria.
Tetanus caused by *Clostridium tetani*
19What group of plants makes flowers?
Angiosperms (Flowering Plants)
20Beans are dicots: What does this mean? Overall, what do we look for to determine if a plant is a dicot?
Dicots have two cotyledons (seed leaves) in their seeds. They have a tap root, net like leaves, and flower in multitudes of 4 and 5.
21It is a nice summer day when pollen from a _______ (part of a flower) blows through the wind. The pollen grain could land on a female _______ in a flower. The pollen grain then germinates and grows down the female _______ and joins up with an _______. This is unique to flowering plants. What do we call this unique process of sexual reproduction? _______.
It is a nice summer day when pollen from a stamen (part of a flower) blows through the wind. The pollen grain could land on a female stigma in a flower. The pollen grain then germinates and grows down the female style and joins up with an ovule. This is unique to flowering plants. What do we call this unique process of sexual reproduction? double ferilization
22What are Oomycota?
Oomycota, also known as water molds, are a group of fungus-like organisms, such as *Phytophthora infestans* which causes potato late blight.
23Do Bacteria have DNA?
YES
24Do Archaea have DNA?
YES
25Do Eukarya have DNA?
YES
26Do Bacteria have a nucleus?
NO
27Do Archaea have a nucleus?
NO
28Do Eukarya have a nucleus?
YES
29Do Bacteria have chloroplasts?
NO
30Do Archaea have chloroplasts?
NO
31Do Eukarya have chloroplasts?
YES
32Do Bacteria have mitochondria?
NO
33Do Archaea have mitochondria?
NO
34Do Eukarya have mitochondria?
YES
35Describe the ecological role and importance of organic matter in soil.
Organic matter improves soil structure, enhances water retention, and facilitates nutrient cycling. It provides food for microorganisms, which in turn support plant growth and soil fertility.
36Explain what cation exchange is and why it is important for soil health.
Cation exchange is the process by which soil particles hold and exchange positively charged ions (cations) like calcium, magnesium, and potassium with plant roots. This is important for nutrient availability and soil fertility.
37Why is it important for soil to have a moderate pH range? Relate to class discussion with one example.
A moderate pH range (6-7) is important because it optimizes nutrient availability and microbial activity. For example, most plants absorb nutrients most efficiently within this pH range.
38List 1 of the 4 major groups of plants (e.g., Bryophytes): Provide their evolutionary age, reproductive strategy, and an actual example.
Bryophytes; Early land plants; Spore-based reproduction; Example: Mosses.
39What are two benefits of earthworms?
Soil Aeration and Nutrient Recycling
40Describe Earthworms ecological role and importance to soil.
they enhance soil structure by mixing organic and inorganic materials, improve water infiltration, and increase the availability of nutrients for plants through decomposition.
41Approximately what fraction of an average soil is "air"?
25%
42What are nematodes?
are microscopic roundworms that play roles in soil ecology, including nutrient cycling and as pests or beneficial organisms.
43What is the thing in front at the arrow? Importance? Explain.
The thing in front at the arrow is likely a nematode. Nematodes are crucial for soil health as they help in decomposition and nutrient cycling, but some species can be plant pathogens affecting crop yields.
44Define Fermentation and provide examples of its significance.
Fermentation is an anaerobic metabolic process where microorganisms convert sugars into energy, producing byproducts like ethanol or lactic acid. It is significant in food production (e.g., yogurt, beer) and in energy generation in oxygen-deprived environments.
45Define the Final Electron Acceptor and its role in ATP production. Provide examples.
The final electron acceptor is the molecule that receives electrons at the end of the electron transport chain during respiration. It plays a crucial role in ATP production. Examples include oxygen in aerobic respiration and nitrate in anaerobic respiration.
46Describe C4 (Photosynthesis) Metabolism and its importance in plants like corn.
C4 metabolism is a photosynthetic process where plants like corn fix carbon dioxide into four-carbon compounds, which are then used in the Calvin cycle. This adaptation helps minimize photorespiration and increases photosynthetic efficiency, especially under high temperature and light conditions.
47What are "chemoautotrophs"? What are they doing in the environment? Where do they get their carbon, energy, and electrons?
Chemoautotrophs are organisms that obtain energy by oxidizing inorganic molecules (like hydrogen sulfide) and use carbon dioxide as a carbon source. They play a role in nutrient cycling by converting inorganic substances into forms usable by other organisms.
48If we wanted to "run a gel" to get DNA fingerprints, what procedure would we perform?
Gel electrophoresis
49"Bands" of DNA end up at the bottom, middle, or top of a gel based on
Fragment size
50What is the result of the following “cutting” of DNA (arrows = cut points)? Draw the result in the box. What is this procedure called?
Restriction Enzyme Digestion; Result: DNA fragments of varying lengths depending on cut points.
51RFLP analysis
Restriction Fragment Length Polymorphism - Allows us to compare the genetic makeup of individuals
52Define Polymerase Chain Reaction (PCR) and its importance in DNA analysis.
Polymerase Chain Reaction (PCR) is a technique used to amplify specific DNA sequences, making it possible to analyze small amounts of DNA for various applications like cloning, sequencing, and forensic analysis.
53Explain using three scenarios why biological control (BC) is difficult using the biology you have learned.
Specificity (control agent must target pests without affecting non-target species)
Environmental factors (changes can affect efficacy)
Establishment (introducing new organism may not establish in ecosystem).
54Describe two different ways we can identify bacteria.
Microscopic Examination (observing shape, size, and staining characteristics); Molecular Methods (using DNA sequencing or PCR to identify genetic markers).
55Explain the process and significance of using organisms for our own benefit (like biological control).
Using organisms for biological control aims to manage pests naturally, reducing the need for chemical pesticides. However, it requires understanding complex ecological interactions to ensure effectiveness and avoid unintended consequences.
56How do living organisms make MOST of their ATP? Describe how that process works.
Most living organisms produce ATP through cellular respiration, which includes glycolysis, the Krebs cycle, and oxidative phosphorylation. In this process, glucose is broken down, and energy from its bonds is used to form ATP molecules.
57How is energy "stored" in ATP?
It is in the bonds between the atoms
58In nature, fungi play three main roles in ecosystems. Name and describe one ecological role fungi have in the environment. How is this role important?
Mutualism, such as mycorrhizal associations with plant roots, enhancing nutrient and water uptake for plants while providing fungi with carbohydrates. This relationship is vital for plant health and ecosystem productivity.
59Define Carbon Fixation and explain the process.
Carbon Fixation is the process by which inorganic carbon (CO₂) is converted into organic compounds by living organisms, primarily through photosynthesis in plants and certain bacteria. It is essential for producing the organic matter that forms the basis of the food chain.
60Explain the significance of Roundup Ready Soybeans.
Roundup Ready Soybeans are genetically modified to be resistant to the herbicide glyphosate. This allows farmers to control weeds without harming the crop, increasing agricultural efficiency and crop yields.
61Explain what is meant by "obligate anaerobe" or "oxygenic photosynthesis." Provide terms, names, and examples.
"Oxygenic photosynthesis" refers to the process by which organisms like plants, algae, and cyanobacteria use light energy to convert water and CO₂ into glucose and oxygen. OR "Obligate anaerobe" refers to an organism that cannot survive in the presence of oxygen. Example: *Clostridium botulinum*.
62What are the A's, T's, G's, and C's in DNA?
Nucleotides
63What are Eukaryotic algae classified as?
Protists
64Ciliates and amoebae are usually
Heterotrophic protists
65Both mitochondria and chloroplasts can change energy forms. Which organelle converts CO₂ using light energy into sugars?
Chloroplasts
66The light-dependent reactions in photosynthesis produce ______, ______, and _______
Produce oxygen, ATP, and NADPH
67Plants like pine trees are
Gymnosperms
68Chlorophyll gets excited by photons of light, such as
Red and blue light
69In which cycle is carbon fixed and sugar is a product?
Calvin Cycle
70The electron donor during the light-dependent reactions is
H₂O
71How can glucose be stored in plants?
As starch
72What is a seed? Similarly, what is a fruit? Explain with examples.
Seed: A seed is an embryonic plant enclosed in a protective outer covering, capable of developing into a new plant. Example: An apple seed. Fruit: A fruit is the mature ovary of a flower, containing seeds. Example: An apple or tomato.
73What are these things?
They are nematodes, which are microscopic roundworms important in soil ecosystems for nutrient cycling and as parasites or beneficial organisms.
74What is the thing in front at the arrow? Importance? Explain.
The thing in front at the arrow is likely a nematode. Nematodes contribute to soil health by decomposing organic matter and controlling pest populations.
75What percentage of Earth's atmosphere is nitrogen (N₂)?
78%
76What is nitrogen fixation and why is it important for natural ecosystems and agriculture?
Nitrogen fixation is the process of converting atmospheric nitrogen (N₂) into ammonia (NH₃) or related compounds usable by living organisms. It replenishes nitrogen available for plant growth and supports nitrogen needs of various organisms.
77Name the prokaryotic groups exclusively involved in nitrogen fixation.
Bacteria, cyanobacteria, actinomycetes
78What enzyme is responsible for nitrogen fixation, and what is its role in the process?
Nitrogenase; it catalyzes the conversion of atmospheric nitrogen (N₂) into ammonium (NH₄⁺), which can be incorporated into proteins and other nitrogenous compounds.
79Describe the Haber-Bosch process and its significance in industrial nitrogen fixation.
The Haber-Bosch process is an industrial method developed in Germany around 1914 for fixing atmospheric nitrogen (N₂) into ammonia (NH₃) by reacting it with hydrogen gas under high temperatures and pressures using an iron catalyst. It produces ammonium nitrate (NH₄NO₃), a key fertilizer, and contributes to approximately 85 million metric tons of ammonia produced annually. It is linked to the cost of fossil fuels and requires significant energy input.
80What is ammonium nitrate (NH₄NO₃), and how is it produced industrially?
Ammonium nitrate (NH₄NO₃) is a compound used primarily as a fertilizer. It is produced industrially through the Haber-Bosch process by reacting ammonia (NH₃) with nitric acid (HNO₃) or by combining nitrogen and hydrogen under high pressure and temperature to form ammonia, which is then oxidized to produce ammonium nitrate.
81What are the environmental and economic factors linked to the Haber-Bosch process?
The Haber-Bosch process requires very high heat and pressure, making it energy-intensive and linked to the high cost of fossil fuels. Approximately 5.5 barrels of oil are needed to produce one ton of ammonia, and natural gas is typically used as the hydrogen source. Environmental factors include significant fossil fuel consumption and greenhouse gas emissions.
82Approximately how many metric tons of ammonia are produced annually through industrial nitrogen fixation?
Around 85 million metric tons.
83Explain the energy requirements of the nitrogenase enzyme in nitrogen fixation. How much of a plant’s ATP does it typically use?
requires magnesium ions (Mg²⁺) and uses 20% of a plant’s ATP to convert N₂ to NH₄⁺.
84Write the chemical equation for biological nitrogen fixation involving nitrogenase.
N₂ + 16 ATP → 2 NH₄⁺ + 16 ADP + 16 Pᵢ + H₂
85Why does nitrogenase not work in the presence of oxygen (O₂)?
Oxygen can hurt the enzyme and prevent the effective fixation of nitrogen, making the process inefficient under aerobic conditions.
86How do specialized cells like heterocysts aid in nitrogen fixation?
Heterocysts are specialized cells found in some filamentous cyanobacteria that provide an anaerobic environment necessary for the functioning of nitrogenase. They lack photosystem II, thereby reducing oxygen production and protecting nitrogenase from oxygen inactivation.
87List at least three environmental conditions that reduce the efficiency of nitrogen fixation.
soil pH levels, Temperature, and availability of minerals phosphorus (P), molybdenum (Mo), and iron (Fe)
88How does nitrogen fixation relate to the use of cover crops in agriculture?
Cover crops, such as legumes, form symbiotic relationships with nitrogen-fixing bacteria (e.g., Rhizobium spp.), enhancing soil nitrogen levels through biological nitrogen fixation. This reduces the need for synthetic fertilizers, improves soil health, and promotes sustainable agriculture.
89Explain how respiration is involved in the nitrogen fixation process.
Respiration ensures that oxygen levels remain low enough to protect the nitrogenase enzyme from inactivation.
90What are nif genes, and how many are typically involved in nitrogen fixation?
nif genes encode the components of the nitrogenase enzyme complex responsible for nitrogen fixation. Approximately 20 nif genes are involved in the regulation, assembly, and function of nitrogenase.
91How is nitrogenase activity regulated in the presence of other nitrogen sources?
Nitrogenase is repressed when other nitrogen sources, such as ammonia or nitrate, are available in the environment. This regulation conserves energy by preventing unnecessary nitrogen fixation when fixed nitrogen is already accessible.
92Discuss the relationship between nitrogen fixation and the availability of phosphorus (P), molybdenum (Mo), and iron (Fe) in the soil.
Nitrogen fixation requires phosphorus (for ATP), molybdenum, and iron (as components of the nitrogenase enzyme). Low availability of these nutrients can limit the efficiency of nitrogen fixation by impairing enzyme function and energy production, thereby reducing the overall nitrogen input into the soil.
93Explain how nitrogenase enzyme complexes are structured and function.
Nitrogenase consists of two protein components with multiple subunits: MoFe protein complex (dinitrogenase), which contains molybdenum and iron and is responsible for the reduction of N₂ to NH₄⁺, and Fe protein complex (dinitrogenase reductase), which transfers electrons to the MoFe protein and facilitates the reduction process. The complex requires ATP and Mg²⁺ to function effectively, facilitating the binding and reduction of nitrogen gas.
94What role does magnesium (Mg²⁺) play in the activity of nitrogenase?
Magnesium ions (Mg²⁺) are essential cofactors that stabilize ATP molecules and are necessary for the proper functioning and structural integrity of the nitrogenase enzyme complex. They facilitate the binding and hydrolysis of ATP, which provides the energy required for nitrogen fixation.
95Describe the different forms of nitrogenase protein complexes and their functions.
Nitrogenase comprises two main protein complexes: MoFe Protein (Dinitrogenase) contains molybdenum and iron and is responsible for the reduction of N₂ to NH₃; Fe Protein (Dinitrogenase Reductase) transfers electrons to the MoFe protein and works with ATP to drive the nitrogen fixation reaction.