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Questions and Answers
What is the primary role of mitochondria within a cell?
Which process results in the formation of two identical daughter cells?
What component of the cell is primarily responsible for storing DNA?
During which phase of the cell cycle does DNA replication occur?
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Which of the following is NOT a function of lysosomes?
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What is produced during meiosis that differs from mitosis?
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What is the term for the process that reduces chromosome numbers for the formation of gametes?
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What occurs during prophase in cell division?
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What does the term 'centromere' refer to in a chromosome?
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What happens to sister chromatids during anaphase?
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Which statement accurately describes the metaphase stage of mitosis?
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Which of the following describes the role of the cell membrane?
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Which type of molecules can pass through the lipid bilayer without assistance?
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What is meant by the term 'selectively permeable' in reference to the cell membrane?
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Which of the following substances would most likely require facilitated diffusion to enter a cell?
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What is the primary requirement for active transport to occur across a cell membrane?
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What is the main characteristic of passive transport across the cell membrane?
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Which statement best describes the sodium-potassium pump?
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Which of these substances needs assistance to cross the cell membrane?
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Which process is used to move very large molecules across the cell membrane?
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What is a characteristic of facilitated diffusion?
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During endocytosis, what happens to the molecules that are engulfed?
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What is the main function of carrier proteins in facilitated diffusion?
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Which of the following statements about facilitated diffusion is false?
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What is the primary source of energy used in active transport?
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Which type of passive transport specifically refers to the movement of water?
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What happens to a cell placed in a hypertonic solution?
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Which of the following describes isotonic solutions?
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Which type of molecules typically move through cell membranes by simple diffusion?
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What effect does a hypotonic solution have on a cell?
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Osmotic pressure is determined primarily by what?
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Which of the following best describes facilitated diffusion?
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What is the primary function of endocytosis in a cell?
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Which of the following best describes phagocytosis?
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Receptor-mediated endocytosis is characterized by what key feature?
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What process is described as 'cellular drinking'?
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Which statement correctly describes exocytosis?
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What role do feedback mechanisms play in homeostasis?
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What key factor differentiates passive transport from active transport?
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Which component is NOT part of the feedback mechanisms that help maintain homeostasis?
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Study Notes
Physiology & Pathophysiology
- Physiology is the study of how things work normally within the body while pathophysiology focuses on how things work during disease.
- Cells are the most basic building blocks of the body, and they organize to form tissues, organs, and organ systems.
Cell Components
- The cytoplasm is an aqueous mass within the cell membrane that contains organelles, including:
- The nucleus: holds DNA, responsible for cellular division and reproduction.
- Mitochondria: fuel cellular activity by producing ATP.
- Ribosomes and the endoplasmic reticulum: synthesize proteins.
- Lysosomes: contain enzymes for cytoplasmic digestion.
Cell Division and Reproduction
- Mitosis produces two identical daughter cells for body cell growth and repair.
- Meiosis is a two-step process that creates sperm and egg cells, reducing the chromosome number from 46 to 23.
- During interphase, the cell duplicates its contents and copies its DNA, creating two sister chromatids connected by a centromere.
- The four phases of mitosis are:
- Prophase: Chromosomes condense, the nuclear envelope breaks down, and mitotic spindles form.
- Metaphase: Chromosomes line up along the metaphase plate.
- Anaphase: Sister chromatids are pulled apart.
- Telophase: The nuclear envelope reforms, chromosomes unfold, and cytokinesis (cytoplasm division) occurs.
Transport Across the Cell Membrane
- The selectively permeable cell membrane regulates the concentration of substances within the cell, including ions, nutrients, and waste products.
- The cell membrane acts as a gate, allowing only specific substances to enter or leave the cell.
- Two categories of transport exist:
- Passive transport: requires no cellular energy.
- Active transport: requires energy from ATP.
Types of Passive Transport
- Simple Diffusion: The movement of substances from an area of higher concentration to an area of lower concentration (down the concentration gradient). Example: oxygen moving into cells and carbon dioxide moving out.
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Osmosis: The diffusion of water across a semipermeable membrane down its concentration gradient, driven by osmotic pressure created by solutes.
- Hypertonic solution: Higher solute concentration, water moves out of the cell, causing it to shrivel.
- Hypotonic solution: Lower solute concentration, water moves into the cell, causing it to swell and potentially burst.
- Isotonic solution: Same solute concentration, water moves in and out at the same rate.
- Facilitated diffusion: Uses transport proteins and channel proteins for polar molecules like glucose to move across the cell membrane, which they cannot pass through via simple diffusion.
Types of Active Transport
- Active transport: Requires energy (ATP) to move substances across the cell membrane, often against their concentration gradient, with the help of protein carriers and pumps.
- Sodium-potassium pump (Na+/K+/ATPase): Moves sodium out of the cell and potassium into the cell, maintaining an electrical gradient.
- Vesicle transport: For large molecules like proteins, uses vesicles for movement into and out of the cell (endocytosis and exocytosis).
Types of Endocytosis
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Endocytosis: Cell membrane invaginates to form a pocket (vesicle) around a particle, taking it into the cell.
- Phagocytosis: Cellular eating, engulfing large particles like bacteria.
- Pinocytosis: Cellular drinking, taking in fluid.
- Receptor-mediated endocytosis: Selective process where external receptors bind a ligand and the cell responds by endocytosing it.
Exocytosis
- Exocytosis: Expels material from the cell into the extracellular fluid. A vesicle containing the material fuses with the cell membrane, releasing the contents outside the cell.
Homeostasis
- The body strives to maintain a state of internal balance called homeostasis.
- External stressors like lack of nutrients or invasion by parasites can disrupt homeostasis and lead to disease.
- Homeostasis is maintained through feedback mechanisms with three components:
- Sensor (receptor): Detects disruptions in homeostasis. - Control center: Regulates the body's response to disruptions. - Effector: Acts to restore homeostasis.
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Description
This quiz explores the fundamental concepts of physiology and pathophysiology, focusing on cell structure and function. It covers key components such as the nucleus, mitochondria, and the processes of mitosis and meiosis. Test your understanding of how these mechanisms contribute to health and disease.