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What does biogenesis propose about the origin of life?
Which scientist is credited with the 3 Jar experiment that disproved spontaneous generation?
What is one of the primary functions of the cell membrane?
Which of the following statements is NOT part of the cell theory?
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What is the main role of mitochondria in a cell?
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What function do vacuoles serve in plant cells compared to animal cells?
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What is the primary composition of ribosomes?
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Peroxisomes are important in which of the following processes?
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What happens to enzymes when the temperature exceeds optimal levels?
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What is the optimal pH range for enzyme activity?
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How does increasing substrate concentration affect the reaction rate?
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What effect does temperature have on enzymes during a fever?
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What happens when the pH level becomes too acidic or too alkaline for enzymes?
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What is the primary role of the Golgi apparatus in a cell?
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Which structure is responsible for enabling movement and chemotaxis in some cells?
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What distinguishes eukaryotic cells from prokaryotic cells?
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Which structure in plant cells is characterized by being rigid and non-living?
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What is the function of the smooth endoplasmic reticulum in a cell?
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What term describes the pressure in plant cells that helps maintain their structure?
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Which of the following best describes cilia?
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What are extremophiles known for?
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What is the primary mechanism of cytokinesis in animal cells?
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Which term describes the failure of chromosomes to separate during cell division?
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What is an example of a structural chromosomal aberration?
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Which syndrome is associated with having an extra X chromosome?
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What forces are primarily responsible for the spontaneous formation of lipid bilayers?
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What is the defining property of lipids that makes them amphipathic?
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Which of the following describes the process of gametogenesis?
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What is the chromosomal condition associated with severe intellectual disability and physical abnormalities?
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What factor does NOT affect the fluidity of the cell membrane?
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How does cholesterol affect membrane fluidity at warm temperatures?
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Which model describes the structure of the plasma membrane as a mosaic of lipids and proteins?
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During sonication, what is the primary purpose of using sound waves?
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What happens to the membrane as temperatures cool?
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What is the consequence of lipid bilayers being semi-permeable?
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Which of the following types of fatty acids lead to a more fluid membrane?
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What structural characteristic defines the phospholipid bilayer of the plasma membrane?
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Study Notes
Abiogenesis and Biogenesis
- Life came from non-living things (abiogenesis).
- Life came from living things (biogenesis).
- Francesco Redi disproved spontaneous generation using a three-jar experiment.
- Louis Pasteur is credited for disproving spontaneous generation.
Cell Theory
- Hooke, Leeuwenhoek, Schleiden, Schwann, and Virchow's discoveries led to the Cell Theory.
- All living things are composed of one or more cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Cell Organelles
- Cell Membrane (Plasma Membrane): Contains a phospholipid bilayer, separates the cell from the external environment, and controls the passage of molecules.
- Cytoplasm: Gelatinous liquid filling the cell, provides structure, and is the site of metabolic reactions.
- Nucleolus: An area within the nucleus made of RNA and proteins, responsible for ribosome synthesis.
- Nucleus: Organelle that houses DNA and directs synthesis of ribosomes and proteins.
- Ribosomes: Composed of RNA and protein, responsible for protein synthesis.
- Mitochondria: Generate chemical energy (ATP - Adenosine Triphosphate) needed for cell processes.
- Peroxisomes: Organelles involved in metabolism, reactive oxygen species detoxification, and signaling.
- Vesicles: Transport materials, regulate waste, and destroy toxic substances and pathogens.
- Vacuoles: Membrane-bound organelles that store waste (animal cells) or maintain water balance (plant cells).
- Centrosome: Cellular structure involved in cell division.
- Chloroplast: Site of photosynthesis (plant cells).
- Cell Wall: A rigid, non-living permeable wall found in most plants, bacteria, fungi, and algae, provides structural support.
- Smooth and Rough Endoplasmic Reticulum: Dynamic structure involved in calcium storage, protein synthesis, and lipid metabolism.
- Golgi Apparatus: Processes and packages proteins and lipids for export out of the cell.
- Cytoskeleton: Maintains cell shape, secures cell position, and allows for intracellular movement.
Prokaryotic and Eukaryotic Cells
- Prokaryotes are single-celled organisms lacking a membrane-bound nucleus. They include bacteria and archaea. Some prokaryotes are multicellular, but most are unicellular.
- Prokaryotes exhibit three main shapes: cocci (round), bacilli (rod-shaped), and spirilla (helical).
- Eukaryotes are organisms with cells containing a membrane-bound nucleus and other membrane-bound organelles.
- Eukaryotes can be unicellular (e.g., protozoa) or multicellular (e.g., plants, animals, fungi).
Cell Division
- Mitosis: A type of cell division that results in two daughter cells with the same number of chromosomes as the parent cell.
- Cytokinesis: The division of the cytoplasm during cell division. It occurs differently in animal and plant cells. In animal cells, a cleavage furrow forms, constricting the cytoplasm until two daughter cells are formed.
- Meiosis: A type of cell division that produces gametes (sperm and eggs) with half the number of chromosomes as the parent cell.
- Spermatogenesis: The process of sperm production.
- Oogenesis: The process of egg production.
Chromosomal Aberrations
- Nondisjunction: The failure of chromosomes to separate during cell division, leading to daughter cells with abnormal numbers of chromosomes.
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Aneuploidy: A condition of having missing or extra chromosomes.
- Turner Syndrome: Missing one X chromosome.
- Klinefelter Syndrome: Extra Y chromosome (XXY).
- Metafemale (Triple X Syndrome): Three X chromosomes (XXX).
- Jacob's Syndrome (Criminal Syndrome): Extra Y chromosome (XYY).
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Autosomal Aberration: Aberration happening to chromosomes 1-22.
- Trisomy 21 (Down Syndrome): Extra chromosome in the 21st pair.
- Trisomy 18 (Edward's Syndrome): Extra chromosome in the 18th pair.
- Trisomy 13 (Patau Syndrome): Extra chromosome in the 13th pair.
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Structural Aberrations: Changes in chromosome structure.
- Deletion: A portion of a chromosome is lost.
- Duplication: A portion of a chromosome is duplicated.
- Inversion: A portion of a chromosome is flipped.
- Translocation: A portion of a chromosome is moved to another chromosome.
Lipids and Cell Membrane
- Lipids: Amphipathic molecules with both hydrophilic and hydrophobic properties.
- Lipid Bilayer: Formed by lipids with bulky polar tails (e.g., glycolipids, phospholipids, cholesterol lipids).
- Micelles: Structures formed by lipids in water.
- Hydrophobic Effect: The key driving force in membrane formation.
- Sonification: Use of sound waves to create artificial liposomes (vesicles).
Membrane Transport Mechanisms
- Plasma Membrane: Regulates the passage of solutes and separates the living cell from its surroundings.
- Semi-permeable Barrier: Due to the lipid bilayer, the plasma membrane is selectively permeable.
- Fluid Mosaic Model: Describes the cell membrane as a fluid bilayer of phospholipids with embedded proteins.
- Davson-Danielli Model: An older model depicting the cell membrane as proteins sandwiched between two lipid layers.
Fluidity of the Cell Membrane
- Factors Affecting Fluidity: Temperature, saturation of fatty acid tails, cholesterol presence, mosaic nature of proteins.
- Temperature and Fluidity: Raising temperature increases fluidity, until extreme temperatures cause denaturation.
- Unsaturated Fatty Acids: Membranes rich in unsaturated fatty acids are more fluid.
- Cholesterol: Moderates fluidity at different temperatures.
Enzyme Function and Activity
- Optimum Temperature: Enzymes have an optimal temperature for activity (often around 37°C for human enzymes).
- High Temperatures: Can denature enzymes and lose their function.
- Denaturation: Destruction of the enzyme's shape, rendering it inactive.
- pH: Enzymes have an optimal pH range for activity. Too acidic or too alkaline can affect enzyme activity.
- Substrate Concentration: Increasing substrate concentration increases the reaction rate until all enzyme molecules are saturated.
- Enzyme Concentration: Increasing enzyme concentration speeds up the reaction rate as long as there is sufficient substrate.
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Description
Explore the concepts of abiogenesis and biogenesis, and their historical significance in the study of life. This quiz also covers the foundational principles of cell theory and details about various cell organelles. Test your understanding of these fundamental biological concepts!
