chapter 6 tour of the cell Flashcards
(95 cards)
What are the three main parameters of microscopy?
- Magnification
- Resolution
- Contrast
These parameters help differentiate and clarify microscopic images.
What is the main difference between scanning electron microscopy (SEM) and transmission electron microscopy (TEM)?
- SEM focuses a beam of electrons onto the surface, providing 3D images
- TEM focuses a beam of electrons through a specimen
SEM provides surface images, while TEM is used for internal structure analysis.
What is cell fractionation?
A process that takes cells apart and separates major organelles from one another
It enables scientists to study the functions of individual organelles.
What are the two main types of cells based on cellular structure?
- Prokaryotic cells
- Eukaryotic cells
Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have both.
What is the role of ribosomes in eukaryotic cells?
Ribosomes use the information from DNA to make proteins
They can be free in the cytosol or bound to the rough endoplasmic reticulum.
What are the components of the endomembrane system?
- Nuclear envelope
- Endoplasmic reticulum
- Golgi apparatus
- Lysosomes
- Vacuoles
- Plasma membrane
These components are involved in regulating protein traffic and performing metabolic functions.
What functions does the smooth endoplasmic reticulum (ER) perform?
- Synthesizes lipids
- Metabolizes carbohydrates
- Detoxifies drugs and poisons
- Stores calcium ions
The smooth ER does not have ribosomes attached.
True or False: The Golgi apparatus modifies products of the rough endoplasmic reticulum.
True
It also manufactures certain macromolecules and sorts materials into transport vesicles.
What is the primary role of lysosomes?
Digest macromolecules using hydrolytic enzymes
They also recycle the cell’s own organelles through a process called autophagy.
What are the primary functions of mitochondria?
Sites of cellular respiration, generating ATP using oxygen
Mitochondria convert chemical energy into a usable form for the cell.
What is the function of chloroplasts?
Sites of photosynthesis
They capture light energy and convert it into chemical energy.
What is the endosymbiont theory?
States that some organelles in eukaryotic cells were once prokaryotic microbes
Mitochondria and chloroplasts are examples, as they have similarities with bacteria.
What are the three types of fibers that compose the cytoskeleton?
- Microtubules
- Microfilaments
- Intermediate filaments
These fibers organize structures and activities within the cell.
How do microtubules contribute to cell function?
Help shape the cell, guide movements of organelles, and separate chromosomes during cell division
They are the thickest component of the cytoskeleton.
What is the function of microfilaments?
Bear tension and resist pulling forces within the cell
They are involved in cellular motility and structural support.
What do plant cell walls protect against?
Excessive uptake of water and help maintain shape
They are made of cellulose fibers embedded in polysaccharides and proteins.
What is the extracellular matrix (ECM) in animal cells made of?
Glycoproteins such as collagen, proteoglycans, and fibronectin
The ECM provides support, adhesion, movement, and regulation.
List the types of intercellular junctions.
- Plasmodesmata
- Tight junctions
- Desmosomes
- Gap junctions
These junctions facilitate communication and adhesion between neighboring cells.
What are plasmodesmata?
Channels that perforate plant cell walls allowing water, small solutes, sugars, and sometimes proteins and RNA to pass from cell to cell
Plasmodesmata are essential for communication and transport between plant cells.
What is the function of tight junctions?
Prevent leakage of extracellular fluid by pressing membranes of neighboring cells together
Tight junctions are crucial for maintaining the integrity of epithelial tissues.
What are desmosomes?
Anchoring junctions that fasten cells together into strong sheets
Desmosomes provide mechanical stability to tissues that experience stress.
What is the role of gap junctions?
Allow small molecules to pass between adjacent cells, serving as communicating junctions
Gap junctions facilitate cell communication and coordination of activities.
What does it mean that the cell is a living unit greater than the sum of its parts?
Cells rely on the integration of structures and organelles to function effectively
This concept emphasizes the importance of cellular organization and cooperation among components.
Which components coordinate in a macrophage to destroy bacteria?
Cytoskeleton, lysosomes, and plasma membrane
The coordination of these components allows macrophages to effectively engulf and digest pathogens.