Chapter 4 Flashcards
What is cytology?
The study of cells.
What is microscopy?
Using a microscope to view small-scale structures
What are the two types of microscopes used to study cells?
Light Microscope (LM) and Electron Microscope (EM).
What is the difference between a Light Microscope and an Electron Microscope?
A Light Microscope uses light to form a 2D image, while an Electron Microscope uses electron beams for higher magnification and resolution.
What is the function of a Transmission Electron Microscope (TEM)?
It directs an electron beam through thin-cut sections, producing a 2D image of internal cell structures.
How does a Scanning Electron Microscope (SEM) work?
It directs an electron beam across the surface of a specimen, producing a 3D image.
What are the three main structural features of a cell?
Plasma membrane, cytoplasm, and nucleus.
What is the function of the plasma membrane?
It forms the outer barrier of the cell and regulates movement of substances in and out.
What extensions of the plasma membrane help in movement or absorption?
Cilia, flagella, and microvilli.
What is the nucleus and what does it contain?
It is the largest cell structure that contains DNA and is enclosed by a nuclear envelope.
What are the components of the cytoplasm?
Cytosol, organelles, and inclusions.
What is cytosol?
intracellular fluid, contains dissolved macromolecules and ions
What are the two main types of organelles?
Membrane-bound and non-membrane-bound organelles.
What is a membrane-bound organelle?
enclosed by a membrane, separates contents from cytosol
What is a non-membrane-bound organelle?
not enclosed within a membrane, composed of protein
Name five membrane-bound organelles.
Endoplasmic Reticulum (ER), Golgi apparatus, lysosomes, peroxisomes, and mitochondria.
Name four non-membrane-bound organelles.
Ribosomes, cytoskeleton, centrosome, and proteasomes.
What is the function of the rough ER?
Protein production and transport.
What are the three main types of lipids in the plasma membrane?
Phospholipids, cholesterol, and glycolipids.
What is the structure of a phospholipid?
A hydrophilic (polar) head and two hydrophobic (nonpolar) tails.
What is the function of cholesterol in the plasma membrane?
Strengthens the membrane and stabilizes it against temperature changes.
What do glycolipids do?
Help form the glycocalyx, which is important for cell recognition.
What are the two main types of membrane proteins?
Integral and peripheral proteins.
What is the role of transport proteins?
To regulate the movement of substances across the membrane
What are cell surface receptors?
Proteins that bind specific molecules (ligands) to trigger cellular responses.
What are identity markers?
Proteins that help the immune system recognize normal cells from foreign ones.
What are the two main categories of membrane transport?
Passive and active transport.
What is the difference between passive and active transport?
Passive transport requires no energy (moves down the concentration gradient), while active transport requires energy (moves against the concentration gradient).
What are the two types of passive transport?
Diffusion and osmosis.
What is simple diffusion?
The movement of small, nonpolar molecules directly across the phospholipid bilayer.
What is facilitated diffusion?
The transport of charged or polar molecules through protein channels or carriers.
What is osmosis?
The passive movement of water through a selectively permeable membrane.
What happens in a hypotonic solution?
Water enters the cell, possibly causing it to burst (lysis).
What happens in a hypertonic solution?
Water leaves the cell, causing it to shrink (crenation).
What is primary active transport?
Uses ATP to move substances against their concentration gradient.
What is secondary active transport?
Uses the movement of one substance down its gradient to power the movement of another against its gradient.
What is endocytosis?
The process of bringing substances into the cell via vesicles.
What are the three types of endocytosis?
Phagocytosis (cell eating), pinocytosis (cell drinking), and receptor-mediated endocytosis.
What are the three types of membrane junctions?
Tight junctions, desmosomes, and gap junctions.
What is the function of tight junctions?
Prevent substances from passing between cells.
What is the function of desmosomes?
Provide mechanical strength by anchoring cells together.
What is the function of gap junctions?
Allow direct communication between cells through small tunnels.
What are the functions of the rough and smooth ER?
Rough ER: Protein synthesis and transport.
Smooth ER: Lipid synthesis and detoxification.
What does the Golgi apparatus do?
Modifies, sorts, and packages proteins for secretion or use in the cell.
What are lysosomes?
Small sacs containing digestive enzymes that break down waste.
What are peroxisomes?
Organelles that detoxify substances and perform lipid metabolism.
What is the main function of mitochondria?
Produces ATP through aerobic respiration (“powerhouse of the cell”).
What are ribosomes?
Structures that synthesize proteins.
What is the centrosome function?
Organizes microtubules and plays a role in cell division.
What do proteasomes do?
Break down damaged or unnecessary proteins.
What are the three components of the cytoskeleton?
Microfilaments – Smallest, provide cell shape.
Intermediate filaments – Provide mechanical support.
Microtubules – Largest, involved in cell transport and division.
hat is the function of flagella?
Propels the entire cell (e.g., sperm).
