The Cell/ Microscopes Flashcards
What is the role of water in biological systems?
The solvent of life, dissolving polar and charged molecules due to its polarity.
Water is essential for various biochemical reactions and processes in living organisms.
What are the four main types of macromolecules?
- Carbohydrates
- Lipids
- Proteins
- Nucleic Acids
Each type of macromolecule plays a critical role in biological functions.
Define carbohydrates.
Polymers of sugars (e.g., glucose).
Carbohydrates serve as energy sources and structural components.
What are lipids?
Not true polymers but hydrophobic molecules (e.g., fats, oils).
Lipids are important for energy storage and cellular membrane structure.
What defines proteins?
Polymers of amino acids; their structure is determined by the sequence and properties of amino acids.
Proteins perform a wide array of functions in biological systems.
What are nucleic acids?
Polymers of nucleotides (e.g., DNA, RNA).
Nucleic acids are essential for storing and transmitting genetic information.
What is polymerization?
The process of linking monomers together (dehydration synthesis).
This process is crucial for forming macromolecules.
What is depolymerization?
Breaking down polymers by adding water (hydrolysis).
This process is important for digestion and recycling of biomolecules.
What is the primary structure of proteins?
Linear sequence of amino acids.
The primary structure is critical for determining the protein’s overall structure and function.
What occurs during the secondary structure of proteins?
Formation of a-helices and B-sheets through hydrogen bonding.
Secondary structures contribute to the overall stability of proteins.
Define tertiary structure in proteins.
Folding of the polypeptide into a 3D structure determined by chemistry of amino acid sidechains.
The tertiary structure is essential for the protein’s functional capabilities.
What is quaternary structure in proteins?
Interaction of multiple proteins to form a complex.
Quaternary structure is important for the functionality of multi-subunit proteins.
What are the core principles of cell theory?
- All living organisms are composed of one or more cells
- The cell is the basic unit of structure and function in living organisms
- All cells arise from the division of pre-existing cells
Cell theory is fundamental to understanding biology and the organization of life.
What is light microscopy?
Uses light to view cells and tissues.
Variants include brightfield, darkfield, and phase contrast microscopy.
What is brightfield microscopy?
Direct light transmission, often requires staining for better contrast.
This method is commonly used for observing fixed and stained specimens.
What is darkfield microscopy?
Illuminates the sample from the side, so that only light that is scattered by the specimen reaches the objective lens.
This technique enhances contrast in unstained samples.
What is phase contrast microscopy?
Enhances contrast by shifting in light phases and gives a pseudo-3D appearance to specimens.
This method is useful for viewing live cells and their internal structures.
What is Transmission Electron Microscopy (TEM)?
Provides detailed internal views of thinly sliced samples.
TEM is capable of very high resolution, allowing for the visualization of cellular organelles.
What is Scanning Electron Microscopy (SEM)?
Produces detailed 3D images of surfaces.
SEM is used to study the surface morphology of samples.
What is resolution in microscopy?
The ability to distinguish two objects as separate entities.
What is magnification?
Increasing the apparent size of the specimen, as a lens does.
How does higher magnification affect resolution?
Higher magnification increases resolution.
What is contrast in microscopy?
Enhances the visibility of structures within the sample.
Does contrast increase resolution?
No, it does not increase resolution.
What are the types of microscopy?
Light Microscopy, Fluorescence Microscopy, Electron Microscopy (EM)
Light Microscopy includes techniques like brightfield, darkfield, phase-contrast, and Differential Interference Contrast (DIC).
What is Light Microscopy?
Techniques that enhance contrast by exploiting light-scattering properties
Includes methods such as brightfield, darkfield, phase-contrast, and DIC.
What does Fluorescence Microscopy utilize?
Fluorophores to visualize specific structures
It emits light when excited by photons, allowing observation of live specimens.
What is the primary advantage of Fluorescence Microscopy?
Visualization of specific cellular structures and ability to observe live cells
Applications also include imaging molecules like proteins and actin filaments.
What is Electron Microscopy (EM)?
A microscopy technique providing higher resolution due to shorter wavelength of electrons
Includes Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM).
What is Transmission Electron Microscopy (TEM)?
Imaging thin sections of specimens to create 2D images with high detail
It provides detailed images of internal structures.
What is Scanning Electron Microscopy (SEM)?
Visualizes 3D surface contours of specimens, typically at lower magnifications
It provides detailed surface images of specimens.
Define fluorescence in the context of microscopy.
Occurs when an electron absorbs light, moves to a higher energy state, and emits light at a longer wavelength.
Which type of microscope provides higher resolution?
Electron microscopes
They require fixed (dead) specimens.
What are prokaryotes?
Typically small (1-3 um), unicellular organisms such as bacteria and archaea.
What distinguishes prokaryotes from eukaryotes?
Prokaryotes have a nucleoid and a single circular chromosome, while eukaryotes have a nucleus and linear chromosomes.
What are eukaryotes?
Larger cells (10-100 um) that include animals, plants, fungi, and protists.
List the fundamental features shared by prokaryotes and eukaryotes.
- Plasma membrane
- Cytoplasm
- Ribosomes
- Cytoskeleton
Fill in the blank: Eukaryotes can be _______ or multicellular.
unicellular
True or False: Prokaryotes have membrane-bound organelles.
False
What are the shared features of prokaryotes and eukaryotes?
Both cell types have essential components like DNA, ribosomes, a plasma membrane, and cytoplasm.
What is a key difference between prokaryotic and eukaryotic cells?
Prokaryotic cells lack a true nucleus and membrane-bound organelles, while eukaryotic cells have a nucleus and organelles.
What is the composition of the plasma membrane?
Composed of a phospholipid bilayer with embedded proteins.
What is contained within the cytoplasm?
Cytosol and organelles where many metabolic reactions occur.
What are ribosomes and their function?
Complexes of proteins and RNA that synthesize proteins from mRNA.
What is the size difference between prokaryotic and eukaryotic ribosomes?
Prokaryotic ribosomes are 70S while eukaryotic ribosomes are 80S.
What is the function of the cytoskeleton?
Maintaining cell shape, aiding in cell division, and transporting substances within the cell.
What is differential centrifugation?
A technique used to separate cell components based on size and density.
How does differential centrifugation work?
Involves spinning samples at different speeds to isolate organelles of interest.
What is Green Fluorescent Protein (GFP)?
A protein derived from jellyfish that emits green light when exposed to blue light.
What is GFP used for in biology?
To visualize cellular structures, processes, and dynamics in living specimens.
Fill in the blank: Prokaryotic ribosomes are _______ while eukaryotic ribosomes are 80S.
70S
True or False: Eukaryotic cells have a true nucleus.
True
What is the structure surrounding the nucleus called?
Nuclear envelope
The nuclear envelope is a double membrane that contains nuclear pores.
What regulates the entry and exit of molecules in the nucleus?
Nuclear pore complex
The nuclear pore complex gates the movement through nuclear pores.
What is chromatin composed of?
DNA and associated proteins
Chromatin is found within the nucleus.
What is the function of the nucleolus?
Assembling ribosomal subunits
The nucleolus is a distinct region within the nucleus.
What does nucleoplasm refer to?
The ‘cytoplasm’ within the nucleus
Nucleoplasm is the viscous fluid filling the nucleus.
What are the primary functions of the nucleus?
Stores genetic material and coordinates activities such as growth, metabolism, and protein synthesis
The nucleus is essential for cellular operations.
What is the Endomembrane System?
A network of membranes that compartmentalizes the cell and regulates the movement of molecules within cells.
What is the Nuclear Envelope?
Continuous with the rough endoplasmic reticulum.
What are the two types of Endoplasmic Reticulum (ER)?
- Rough ER
- Smooth ER
What is the function of Rough ER?
Involved in protein synthesis, folding, and modification.
What is the function of Smooth ER?
Involved in lipid synthesis and detoxification.
What is the role of the Golgi Apparatus?
Modifies proteins received from the ER, adds finishing touches like sugars, and sorts them for delivery.
What do Vesicles do in the Endomembrane System?
Transport materials between different parts of the endomembrane system.
What are Lysosomes?
Contain digestive enzymes to break down waste materials and cellular debris.
What is the function of the Plasma Membrane?
Regulates what enters and exits the cell.
What does Compartmentalization in cells allow for?
Different metabolic processes can occur in specific, controlled environments within the cell.
What is Membrane Trafficking?
Movement of proteins and other molecules through vesicles between organelles.
Fill in the blank: Proteins are synthesized in the ER, modified in the ________, and transported to their final destinations.
Golgi
True or False: The Smooth ER is studded with ribosomes.
False
What is exocytosis?
The process where vesicles move materials from the ER to the Golgi and then to the plasma membrane to be secreted from the cell.
What is endocytosis?
The process where the plasma membrane engulfs external materials and brings them into the cell in vesicles.
Give an example of exocytosis.
Neurotransmitter release.
Give an example of endocytosis.
Viral entry into cells.
Fill in the blank: _______ is the process where vesicles move materials from the ER to the Golgi.
[Exocytosis]
Fill in the blank: _______ is the process where the plasma membrane engulfs external materials.
[Endocytosis]
True or False: Exocytosis involves bringing materials into the cell.
False
True or False: Endocytosis is a process that involves the secretion of materials from the cell.
False
What is the function of the Nuclear Envelope?
Controls what enters and exits the nucleus
The nuclear envelope is a double membrane that surrounds the nucleus in eukaryotic cells.
What are the two types of Endoplasmic Reticulum (ER)?
- Rough ER: Protein synthesis and folding
- Smooth ER: Lipid synthesis and detoxification
The Rough ER is studded with ribosomes, while the Smooth ER lacks ribosomes.
What is the role of the Golgi Apparatus?
Modifies proteins and sorts them into vesicles for transport
The Golgi apparatus is often referred to as the cell’s ‘post office’.
What is the purpose of Vesicles in the Endomembrane System?
Transport materials between cellular compartments
Vesicles can carry proteins, lipids, and other molecules.
What is the function of Lysosomes?
Digestive organelles that break down waste and engulfed materials
Lysosomes contain hydrolytic enzymes for digestion.
What do Vacuoles do in plant and fungal cells?
- Regulate turgor pressure
- Store nutrients
Vacuoles can also store waste products.
What is the function of the Plasma Membrane?
Regulates what enters and leaves the cell
The plasma membrane is selectively permeable.
Fill in the blank: The __________ is involved in lipid synthesis and detoxification.
[Smooth ER]
The Smooth ER is crucial for the metabolism of lipids.
True or False: The Rough ER is involved in lipid synthesis.
False
The Rough ER is primarily involved in protein synthesis.
What are the two main types of semi-autonomous organelles?
Mitochondria and Chloroplasts
What do mitochondria generate?
ATP
What do chloroplasts generate?
Sugars
What process do mitochondria participate in?
Respiration
What process do chloroplasts perform?
Photosynthesis
What unique features do both mitochondria and chloroplasts share?
They have their own DNA and ribosomes, replicate independently, and have double membranes
Mitochondria and chloroplasts originated from _______.
[ancient prokaryotic symbionts]
What are the components of the cytoskeleton?
Microtubules, Microfilaments, Intermediate Filaments
Each component has distinct roles in maintaining cell structure and function.
What are microtubules composed of?
Polymers of tubulin
Microtubules maintain cell shape, aid in cell division, and serve as tracks for organelle movement.
What are the functions of microfilaments?
Support organelle movement, cell movement, division, and structural support
Microfilaments are polymers of actin.
What are intermediate filaments made of?
Polymers of intermediate filament proteins
Intermediate filaments are found in some eukaryotes like animals, but not in plants or fungi.
What is one function of the cytoskeleton?
Maintain cell shape
The cytoskeleton provides mechanical support and facilitates cell adhesion.
Fill in the blank: Microtubules aid in _______.
cell division
They also maintain cell shape and serve as tracks for organelle movement.
True or False: Intermediate filaments are found in plants.
False
Intermediate filaments are found in some eukaryotes like animals but not in plants or fungi.
What are the components of the cytoskeleton?
Intermediate Filaments, Microtubules, Microfilaments
Intermediate filaments provide structural support, microtubules maintain cell shape and facilitate transport, and microfilaments support cell shape and movement.
What are intermediate filaments made of and what is their primary function?
Made of proteins like keratin and collagen; provide structural support and adhesion
Found in animal cells; plants and fungi lack intermediate filaments.
What is the primary role of microtubules?
Maintain cell shape, enable intracellular transport, facilitate cell division
Composed of tubulin; motor proteins kinesins and dyneins move along microtubules.
What are microfilaments composed of?
Actin
They support cell shape, movement, and division.
How do myosin motor proteins interact with microfilaments?
They walk along microfilaments, playing a role in muscle contraction and cellular migration
Myosin is essential for movement in muscle cells.
What functions do microtubules and microfilaments serve in relation to cell shape?
Help maintain cell shape
They contribute to cell polarity and structural integrity.
What role do microtubules play in cell division?
Organize chromosomes during mitosis
They are crucial for the proper segregation of chromosomes.
What aids in cytokinesis?
Microfilaments
They assist in the division of the cytoplasm during cell division.
What is the function of motor proteins in the cytoskeleton?
Transport organelles and vesicles
They move along microtubules and microfilaments to facilitate intracellular transport.
What structures facilitate cell movement or fluid movement over cell surfaces?
Cilia and flagella
Driven by microtubules and dynein.
What is the primary composition of the Extracellular Matrix (ECM) in animals?
Primarily proteins (e.g., collagen) and glycoproteins
The ECM in animals provides structural support, cell adhesion, and cell shape.
What do the ECM components consist of in plants, fungi, and bacteria?
Cell walls
Plant cell walls are primarily composed of cellulose, fungi use chitin, and bacteria have peptidoglycan.
What is one of the main functions of the ECM?
Support
The ECM provides structural integrity to tissues and organs.
What role does the ECM play in cell adhesion?
Holds cells together or attaches them to surfaces
This function is crucial for maintaining tissue structure.
How does the ECM provide protection?
Acts as a barrier against physical damage and pathogens
The protective role is essential for maintaining tissue health.
What is a function of the ECM in intercellular communication?
Facilitates selective transport through structures like plasmodesmata and gap junctions
Plasmodesmata are found in plants, while gap junctions are present in animals.
Fill in the blank: The ECM in animals provides _______ support, cell adhesion, and cell shape.
[structural]
True or False: The ECM is only found in animal cells.
False
ECM is also found in plants, fungi, and bacteria, taking different forms.
