Questions and Answers
What is the primary function of mitosis?
Which transport mechanism is characterized by the ingestion of large solid particles?
Which of the following statements is true about meiosis?
What is the role of the axon in nerve physiology?
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Which type of transport uses ATP to transport substances against their concentration gradient?
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What occurs during the telophase of cell division?
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Which structure is responsible for detoxifying free radicals such as alcohol?
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What is a characteristic of the cytoskeleton?
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What is the function of mitochondria in a cell?
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Which part of the cell is primarily involved in the synthesis and transport of proteins?
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What type of cell fluid accounts for 60% of the total water in the body?
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Which component of the cell membrane is hydrophilic?
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Which structure surrounds and protects the nucleus of the cell?
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What is the main role of lysosomes within the cell?
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Which type of fluid is found in the plasma?
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What do proteins in the cell membrane NOT serve as?
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Study Notes
Basic Biological Levels
- Cells are the fundamental unit of life in all organisms.
- The chemical level involves the combination of atoms forming molecules.
- Molecules combine to form cells, which aggregate into tissues.
- Tissues build organs, which further form organ systems.
- Organ systems together comprise an organism.
Cellular Composition
- Protoplasm is the substance filling the cell, with water being the most abundant component (60%).
- Water distribution: 40% intracellular fluid (ICF), 20% extracellular fluid (ECF), composed of 5% plasma and 15% interstitial fluids.
Cell Structure
- The cell membrane is the outer layer, characterized by:
- A bilayer of lipids, amphipathic nature with hydrophilic heads and hydrophobic tails.
- Semi-permeability allowing gas passage, specifically oxygen and carbon dioxide.
- Cytoplasm acts as the inner environment, housing organelles and separating the nucleus from the membrane.
Nucleus and Genetic Material
- The nucleus serves as the control center of the cell, containing DNA and surrounded by a nuclear envelope for protection.
- The nucleolus is integral for ribosome production.
Organelles and Their Functions
- Mitochondria are known as the powerhouse, generating ATP for energy.
- Endoplasmic reticulum is crucial for protein and lipid synthesis:
- Rough ER creates protein vesicles.
- Smooth ER focuses on lipid synthesis and detoxification.
- Golgi apparatus modifies and packages proteins from the rough ER.
- Lysosomes contain hydrolase enzymes for digesting unwanted substances and damaged cells, instrumental in macrophages and neutrophils.
Cytoskeleton and Cell Movement
- The cytoskeleton provides structural support.
- Cilia facilitate movement over the cell surface, while flagella enable sperm mobility (longer than cilia).
- Spindle fibers assist in chromosome separation during cell division, with centrioles being key to microtubule formation.
Cell Division Processes
- Mitosis results in two daughter cells with the same chromosome number, essential for growth and tissue repair; somatic cells are diploid.
- Meiosis creates four gametes, each with half the chromosome count; vital for sexual reproduction and results in haploid cells.
Phases of Cell Division (PMAT)
- Prophase: Chromosomes pair and condense.
- Metaphase: Chromosomes align at the midline.
- Anaphase: Chromatids split and move towards opposite ends.
- Telophase: Nucleus reappears, and cells begin to divide.
Cell Transport Mechanisms
- Exocytosis expels cellular contents; endocytosis ingests materials, including subtypes:
- Phagocytosis for large solid particles (cell eating).
- Pinocytosis for small liquids (cell drinking).
- Diffusion (passive transport) allows molecules to move from higher to lower concentration:
- Simple diffusion occurs spontaneously, while facilitated diffusion involves carrier proteins.
- Osmosis entails water movement from higher to lower solute concentration.
Active Transport Mechanisms
- Active diffusion moves substances against their concentration gradient, requiring energy:
- Primary active transport utilizes ATP directly.
- Secondary active transport derives energy from primary transport.
Nerve Physiology
- Dendrites transmit action potentials towards the cell body, while axons relay them away.
- The myelin sheath insulates electrical signals, with nodes of Ranvier enhancing conduction speed.
- The axon hillock triggers generation of electrical signals.
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Description
Explore the fundamental concepts of biology with this quiz focusing on the basic unit of life, the cell, and its organization into tissues, organs, and systems. Understand the chemical levels including molecules, protoplasm, and the significance of water in cellular function. This quiz delves into the composition of cells and their roles in the hierarchy of life.