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What role does tryptophan (Trp) play in regulating gene expression?
What happens when both repression and attenuation occur due to high levels of Trp?
What is the outcome of using restriction enzymes on DNA?
What is the primary function of DNA polymerase in the context of DNA modification?
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In gel electrophoresis, what determines the distance DNA samples travel?
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What is one benefit of using CRISPR technology on crops?
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Which fermentation process occurs in animals during anaerobic respiration?
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Which enzyme's affinity to CO2 can be improved using CRISPR technology?
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What is the primary role of oxygen in cellular respiration?
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How many ATP are produced through glycolysis?
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What is the first step in both aerobic and anaerobic respiration?
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Where does the Krebs Cycle occur within the cell?
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In the biofuel production process, what is the role of yeast?
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What inputs are required for the Electron Transport Chain?
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Which type of cell is primarily responsible for phagocytosis of pathogens?
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Which stage of cellular respiration generates the most ATP?
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Which coenzymes travel to the Electron Transport Chain from glycolysis and the Krebs Cycle?
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How does increasing glucose concentration affect cellular respiration?
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What is one of the key functions of natural killer cells in the immune response?
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Which of the following statements about CRISPR and crop yields is true?
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Which type of cells migrate to the lymph nodes to activate T-helper cells?
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What is the primary effect of genetic drift on allele frequencies in populations?
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Which example illustrates natural selection in bacteria?
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What does the founder effect lead to in newly established populations?
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How does natural selection contribute to speciation?
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What leads to the ineffectiveness of vaccines over time?
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What role do cytokines play in the inflammatory response?
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What causes the site of damage to become hot, swollen, and red during inflammation?
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How does the adaptive immune response provide long-term immunity?
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What initiates the activation of the T-helper cell in the adaptive immune response?
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What is the main function of plasma B cells during the adaptive immune response?
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Which part of the immune response is responsible for directly attacking infected cells?
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What is the primary function of the physical barriers in plant immunity?
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Which of the following is NOT considered a chemical barrier in plant immunity?
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Study Notes
Trp Operon
- Trp binds to the repressor protein
- The Trp-repressor protein complex binds to the operator region
- RNA polymerase cannot produce genes E-A
- When the Trp levels are high, the repressor protein binds to the operator region
- The repressor protein blocks RNA polymerase from transcribing the genes
- When Trp levels are low, the repressor protein detaches from the operator region
- RNA polymerase can transcribe the genes E-A
- The Trp operon regulates the amount of Trp produced by the cell
- Attenuation is another mechanism for regulating Trp production
- When Trp levels are high, both repression and attenuation can occur
- The ribosome is detached from the attenuated mRNA
- No Trp is produced
- The cell conserves energy and resources
DNA Modification
- Restriction enzymes cut phosphodiester bonds in DNA
- Sticky ends allow for easier insertion of the target gene in the correct orientation
- Blunt ends have no overhang
- Ligase repairs broken phosphodiester bonds in DNA
- Polymerases build DNA (eg Taq polymerase) and RNA
- DNA polymerase is used in PCR
Gel Electrophoresis
- DNA samples are cut with restriction enzymes to expose STR sites
- DNA samples are loaded into wells
- Electronic current is used to separate samples from largest (travel least distance) to smallest (travel the furthest distance)
- Samples with the largest molecular weight travel the shortest distance
- Samples with the smallest molecular weight travel the furthest distance
CRISPR and Crops
- CRISPR technology can be used to modify crops
- CRISPR can modify crops to improve photosynthetic efficiency
- CRISPR can improve rubisco's affinity to CO2
- CRISPR can improve chlorophyll's ability to capture all wavelengths of light
- CRISPR can improve the speed of reactions in photosynthesis
- CRISPR can also be used to modify crops to improve their crop yields
- CRISPR can increase the number of harvests per stem and accelerate the time it takes for the crop to mature
Cellular Respiration
- Cellular respiration uses glucose (organic energy) to produce ATP from ADP+Pi
- Respiration can be aerobic (requires oxygen) and anaerobic (no oxygen)
Stages of Aerobic Respiration
-
Glycolysis
- Inputs: Glucose, NAD+
- Outputs: 2x Pyruvate, NADH
- Location: Cytoplasm
- Net: 2 ATP produced
-
Krebs Cycle
- Inputs: 2x Acetyl CoA, NAD+, FAD+
- Outputs: CO2, NADH, FADH2
- Location: Matrix of mitochondria
- Net: 2 ATP produced
-
Electron Transport Chain
- Inputs: FADH2, NADH, ADP+Pi, Oxygen
- Outputs: NAD+, FAD+, ATP, Water
- Location: Cristae of Mitochondria
- Net: 26-28 ATP produced
- Glycolysis is always the first step in both aerobic and anaerobic respiration
- The link reaction occurs when pyruvate enters the mitochondria and is converted into acetyl CoA
- NADH and FADH2 from glycolysis and Krebs travel to the ETC, creating a proton gradient
- Protons pass through ATP synthase, producing ATP from ADP+Pi
- Oxygen is the final electron acceptor
Anaerobic Respiration
- Anaerobic respiration occurs in all living things
- It is always the first step in respiration (Glycolysis)
- Lactic acid formation occurs in animals
- Alcoholic fermentation occurs in yeast and plants
- Glycolysis produces the 2 ATP in anaerobic respiration
Factors Affecting Cellular Respiration
- Increasing glucose and oxygen concentration will cause the same graph
- Increasing temperature will increase rate of reaction to a point where enzymes denature
- Increasing pH can have an effect on enzymes
Biofuel
- Biofuel is sustainable
- Biofuel is made through anaerobic fermentation
- Biofuel is made from organic plant waste
- Organic plant waste is broken down into glucose
- Glucose is supplied to yeast in fermentation chambers
- Yeast use glucose to undergo anaerobic fermentation
- Bioethanol is harvested and purified for commercial use
Innate Immunity
-
Macrophages
- APC - phagocytosis of pathogen and displays foreign antigen as MHCII
-
Dendritic Cells
- APC - phagocytosis of pathogen and displays foreign antigen as MHCII
-
Neutrophils
- APC - phagocytosis of pathogen and displays foreign antigen as MHCII
-
Eosinophils
- Responsible for parasite infections
-
Natural Killer Cells
- Attack body cells with defective MHC1 via the release of perforins
-
Mast Cells
- Inflammation & histamine release
- Allergic responses & histamine release
Antigen Presentation
- Antigen presenting cells (APCs)
- Macrophages
- Dendritic cells
- Neutrophils
- APCs migrate to the lymph node and activate T-helper cells
- Cytokines are released from damaged tissue
- Immune cells move to the site of damage
- Mast cells release histamine
- Histamine causes:
- Leaky capillaries
- Vasodilation
- Site becomes hot, swollen, and red due to increased cellular activity
- Macrophages remove debris
Adaptive Immune Response
- Adaptive immune response provides long-term immunity to pathogens and protects against reinfection through the production of memory cells.
- The adaptive immune response is coordinated by the T-helper cell after antigen presentation
-
Humoral (B Cell) Response
- T-helper cell is activated by APC
- T-helper cell releases cytokines and activates naïve B-cell
- Naïve B-cell undergoes clonal selection to produce plasma B-cell and memory B-cell
- Plasma B-cell produces specific antibodies that bind to and neutralize foreign antigen
- Memory B-cell remains in the bloodstream and provides long-term immunity against subsequent infections
-
Cell-mediated (T Cell) Response
- T-helper cell is activated by APC
- T-helper cell releases cytokines and activates naïve T-cell
- Naïve T-cell undergoes clonal selection to produce specific cytotoxic T-cells
- Cytotoxic T-cells attack cells with specific defective MHC1, causing apoptosis or releasing perforins
- Memory T-cells provide long-term immunity
Plant Immunity
- Plants have no adaptive immune responses
-
Physical Barriers
- Thorns
- Trichomes (hairs)
- Waxy cuticle
- Lignin walls
-
Chemical Barriers
- Enzymes
- Essential Oils
- Phytoalexins
- Defensins
Preventing the Spread of Pathogens
- Identify the pathogen
- Identify its transmission
- Develop a vaccine
- Monoclonal antibodies are given as treatment
- Direct contact can also spread pathogens
Genetic Drift
- Genetic drift is a random change event that can cause changes in allele frequencies in populations.
- Genetic drift is not an example of natural selection.
Bottleneck Effect
- Chance event where randomly some members of the population survive a natural disaster and others do not
- Affects smaller populations more than bigger populations.
- Can result in the loss of alleles from the population
- Decreases variation in the population
Founder Effect
- Small number of members branch off to form a brand new population.
- Only the alleles present in the founding individuals will be present in the new population
- Causes a decrease in variation
- Decreases variation in the population
Natural Selection
- Natural selection is the driving force for evolution.
- Variation in a population allows for traits to be selected for (fit) or selected against (unfit).
- Over time, the allele frequency changes depending on the organism's environment
- Natural selection can lead to speciation.
- Natural selection reduces genetic variation in a population
Natural Selection Example: Bacterial Resistance
- VARIATION: In a population of bacteria, some have resistance to antibiotics, others do not.
- SELECTION PRESSURE: Exposure to antibiotics; only those with resistance survive and reproduce (no resistance = no survival).
- FUTURE GENERATIONS: Higher allele frequency of resistant bacteria.
- NATURAL SELECTION OCCURED.
Antigenic Shift and Drift
- Vaccines become ineffective due to random mutations in the virus over time.
- This can be gradual and minimal changes or can be abrupt.
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Description
This quiz covers key concepts of the Trp operon and DNA modification techniques such as restriction enzymes and ligase functions. Understand the mechanisms of gene regulation through the Trp operon and the importance of DNA modification in genetic engineering. Test your knowledge on these essential molecular biology topics.