Cell structure Flashcards
What is the fundamental concept of cell theory?
Cell theory states that all living organisms are composed of one or more cells, which are the basic structural and functional units of life.
Why are cells considered the basic structural unit of life?
Cells are the smallest units that can carry out all life processes, including metabolism, growth, and reproduction, making them essential for all living organisms.
How does cell theory apply to newly discovered organisms?
Based on cell theory, scientists can predict that any newly discovered organism will consist of one or more cells, regardless of its complexity.
What is deductive reasoning in the context of biology?
Deductive reasoning involves generating predictions based on established theories, such as predicting the cellular structure of new organisms based on cell theory.
What types of organisms are made up of a single cell?
Unicellular organisms, such as bacteria and yeast, consist of only one cell and perform all necessary life functions within that single unit.
What types of organisms are multicellular?
Multicellular organisms, such as plants, animals, and fungi, are composed of many cells that work together to perform specialized functions.
How do cells contribute to the complexity of multicellular organisms?
In multicellular organisms, cells differentiate into various types (e.g., muscle cells, nerve cells) that perform specific functions, allowing for greater complexity and specialization.
What is an example of a specialized cell type in multicellular organisms?
Neurons are specialized cells in animals that transmit electrical signals throughout the body, playing a critical role in communication and response to stimuli.
Why is understanding cell structure important in biology?
Understanding cell structure helps explain how different cellular components work together to sustain life processes and how dysfunctions can lead to diseases.
How does the study of cells relate to advancements in medicine?
Insights into cellular structures and functions have led to developments in medical treatments, including targeted therapies for diseases like cancer and regenerative medicine techniques.
What is the primary purpose of microscopy in biology?
Microscopy allows scientists to observe and study cells and tissues at a magnified scale, revealing details that are not visible to the naked eye.
What is a temporary mount in microscopy?
A temporary mount is a preparation method where specimens are placed on a slide with a cover slip for observation under a microscope, allowing for the examination of living or freshly prepared samples.
Why is staining important in microscopy?
Staining enhances contrast in specimens, making specific structures more visible and allowing for better differentiation between different cell types or components.
What is an eyepiece graticule?
An eyepiece graticule is a measuring device fitted into the eyepiece of a microscope, used to measure the size of objects observed through the microscope.
How do you calculate actual size using an eyepiece graticule?
To calculate actual size, measure the size of the object using the graticule, then use a stage micrometer to determine the calibration factor for converting graticule units to actual measurements.
What is the difference between coarse and fine adjustments on a microscope?
Coarse adjustments are used for making large changes in focus, while fine adjustments allow for precise focusing on the specimen.
How do you produce a scale bar in microscopy images?
A scale bar can be produced by measuring an object of known size in the image and then drawing a line representing that size, providing a reference for scale in photographs.
Why is taking photographs of microscopic specimens useful?
Taking photographs allows for documentation and analysis of specimens, enabling comparison over time and sharing findings with others in the scientific community.
What type of observations are considered quantitative in microscopy?
Measurements taken using instruments, such as sizes of cells or structures using an eyepiece graticule, are forms of quantitative observation that provide numerical data.
How can microscopy skills contribute to advancements in biological research?
Mastery of microscopy techniques enhances understanding of cellular structures and functions, leading to discoveries in areas such as cell biology, genetics, and disease pathology.
What are the advantages of electron microscopy?
Electron microscopy offers high resolution and magnification, allowing for detailed visualization of cellular structures at the nanometer scale, which is not achievable with light microscopy.
How does freeze fracture microscopy work?
Freeze fracture microscopy involves freezing a specimen and then fracturing it to reveal internal structures, providing insights into membrane organization and protein distribution.
What is cryogenic electron microscopy (cryo-EM)?
Cryo-EM is a technique that allows for the imaging of biological specimens at very low temperatures, preserving their native state and providing high-resolution images without the need for staining.
What are the benefits of using fluorescent stains in light microscopy?
Fluorescent stains enhance contrast by binding to specific cellular components, allowing for visualization of structures and processes within cells, such as protein localization and dynamic cellular events.
What is immunofluorescence, and how is it used in microscopy?
Immunofluorescence uses antibodies labeled with fluorescent dyes to detect specific proteins or antigens in cells, providing valuable information about protein expression and localization.
How does electron microscopy compare to light microscopy?
Electron microscopy provides significantly higher resolution than light microscopy, enabling the observation of smaller structures like ribosomes and viruses, but it requires more complex sample preparation.
Why is cryo-EM considered a breakthrough in structural biology?
Cryo-EM allows researchers to visualize large macromolecular complexes in their native environments without crystallization, facilitating the study of proteins and other biomolecules in detail.
What challenges are associated with using electron microscopy?
Challenges include the need for a vacuum environment, potential damage to biological samples due to electron beams, and complex sample preparation techniques that can be time-consuming.
How do fluorescent stains contribute to dynamic studies in live cells?
Fluorescent stains can be used to label live cells, allowing researchers to observe real-time cellular processes such as cell division, movement, and interactions between proteins.
Why is it important to continually develop new microscopy techniques?
Advancements in microscopy techniques enhance our understanding of cellular structures and functions, leading to new discoveries in biology, medicine, and materials science by providing deeper insights into complex biological systems.
What is the primary genetic material found in all living cells?
DNA is the primary genetic material in all living cells, containing the instructions necessary for growth, development, and reproduction.
Why is DNA essential for cellular function?
DNA stores genetic information that guides the synthesis of proteins, which are crucial for cellular structure and function, enabling organisms to carry out life processes.
What is the composition of cytoplasm in typical cells?
Cytoplasm is primarily composed of water, along with dissolved ions, nutrients, and organic molecules, providing a medium for biochemical reactions.
How does water contribute to cellular processes?
Water serves as a solvent for biochemical reactions, facilitates transport of molecules within the cell, and helps maintain cell structure through turgor pressure in plant cells.
What role does the plasma membrane play in cells?
The plasma membrane encloses the cell, regulating the movement of substances in and out of the cell, thus maintaining homeostasis and protecting cellular integrity.
What is the structure of the plasma membrane?
The plasma membrane consists of a lipid bilayer with embedded proteins, allowing it to be flexible and selectively permeable to various substances.
Why are lipids important in forming the plasma membrane?
Lipids form the hydrophobic core of the membrane, preventing free passage of water-soluble substances while allowing lipid-soluble molecules to diffuse through.
How does the presence of a plasma membrane benefit cells?
The plasma membrane allows cells to maintain distinct internal environments, essential for optimal functioning and adaptation to external conditions.
What are some common features shared by all living cells?
Common features include DNA as genetic material, cytoplasm as a medium for biochemical reactions, and a plasma membrane that regulates cellular interactions with the environment.
How does understanding cell structures contribute to biology?
Understanding cell structures provides insights into how organisms function, interact with their environments, and evolve over time, forming the basis for fields such as genetics and biotechnology.
What are the main components of prokaryotic cell structure?
Prokaryotic cells typically consist of a cell wall, plasma membrane, cytoplasm, naked DNA in a loop, and 70S ribosomes.
What is the function of the cell wall in prokaryotes?
The cell wall provides structural support and protection, helping to maintain cell shape and prevent lysis in hypotonic environments.
How does the plasma membrane contribute to prokaryotic cell function?
The plasma membrane regulates the movement of substances in and out of the cell, maintaining homeostasis and facilitating communication with the environment.
What is the composition of the cytoplasm in prokaryotic cells?
The cytoplasm is a gel-like substance composed mainly of water, enzymes, nutrients, and other molecules necessary for cellular processes.
Describe the structure of naked DNA in prokaryotes.
Naked DNA in prokaryotes is typically found in a circular loop, not associated with histones, and is located in a region called the nucleoid.
What are 70S ribosomes, and why are they important in prokaryotic cells?
70S ribosomes are the site of protein synthesis in prokaryotic cells, composed of 50S and 30S subunits, allowing for efficient translation of mRNA into proteins.
How do Gram-positive eubacteria differ from other prokaryotes?
Gram-positive eubacteria have a thick peptidoglycan layer in their cell wall, which retains the crystal violet stain used in Gram staining, making them appear purple under a microscope.
What is one example of a Gram-positive eubacterium?
Bacillus and Staphylococcus are examples of Gram-positive eubacteria known for their thick cell walls and ability to form spores.
Why is it important to understand variations in prokaryotic cell structure?
Understanding variations helps clarify how different prokaryotic organisms adapt to their environments and perform unique functions, contributing to biodiversity.
What challenges do scientists face when studying prokaryotic cells?
Challenges include their small size, which makes observation difficult without advanced microscopy techniques, and their diverse structures that complicate classification and study.
What are the key features of eukaryotic cells?
Eukaryotic cells have a plasma membrane, compartmentalized cytoplasm, 80S ribosomes, a nucleus with double membranes, and various membrane-bound organelles.
What is the function of the plasma membrane in eukaryotic cells?
The plasma membrane regulates the movement of substances into and out of the cell, providing protection and maintaining homeostasis.
How does compartmentalization benefit eukaryotic cells?
Compartmentalization allows different cellular processes to occur simultaneously in specialized organelles, enhancing efficiency and organization within the cell.
What is the significance of 80S ribosomes in eukaryotic cells?
80S ribosomes are involved in protein synthesis, translating mRNA into proteins, which are essential for cell function and structure.
Describe the structure and function of the nucleus in eukaryotic cells.
The nucleus is surrounded by a double membrane (nuclear envelope) with pores, containing chromosomes made of DNA bound to histones, regulating gene expression and storing genetic information.
What are some examples of membrane-bound organelles found in eukaryotic cells?
Examples include mitochondria (energy production), endoplasmic reticulum (protein and lipid synthesis), Golgi apparatus (modification and transport of proteins), and lysosomes (digestion of waste).
How do mitochondria contribute to cellular function?
Mitochondria are known as the “powerhouses” of the cell, generating ATP through cellular respiration, which provides energy for various cellular activities.
What role does the endoplasmic reticulum play in eukaryotic cells?
The endoplasmic reticulum (ER) is involved in synthesizing proteins (rough ER) and lipids (smooth ER), as well as detoxifying harmful substances.
How does the Golgi apparatus function within a eukaryotic cell?
The Golgi apparatus modifies, sorts, and packages proteins and lipids received from the ER for secretion or delivery to other organelles.
