Cellular Structures Flashcards
7 cards from real Histology Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Cellular Structures flashcards as text
Which organelle is responsible for post-translational modification and sorting of proteins destined for secretion?
Answer: Golgi apparatus
The Golgi apparatus processes, modifies (e.g., glycosylation), and sorts proteins received from the RER for secretion, lysosomal targeting, or membrane insertion.
In histological sections stained with H&E, mitochondria are best described as:
Answer: Eosinophilic structures that are generally below the resolution of light microscopy as individual organelles
Mitochondria are too small (~0.5–1 µm) to be individually resolved by light microscopy; their collective contribution gives cytoplasm a diffuse eosinophilic hue.
The inner mitochondrial membrane is characterized by extensive folding into structures called:
Answer: Cristae
Cristae are infoldings of the inner mitochondrial membrane that dramatically increase surface area for oxidative phosphorylation.
Which cellular structure forms the primary diffusion barrier between the cytoplasm and the extracellular environment?
Answer: Plasma membrane
The plasma membrane's phospholipid bilayer is the principal selective permeability barrier regulating molecular exchange between the cell and its environment.
Free ribosomes in the cytoplasm predominantly synthesize proteins destined for:
Answer: Cytosolic use or import into mitochondria and nucleus
Free ribosomes synthesize proteins used within the cytosol or targeted post-translationally to organelles like mitochondria, peroxisomes, and the nucleus.
The nuclear lamina, located on the inner surface of the nuclear envelope, is composed primarily of:
Answer: Intermediate filaments called lamins
Lamins are type V intermediate filaments that polymerize to form the nuclear lamina, providing mechanical support to the nuclear envelope and anchoring chromatin.
Which cellular compartment maintains an acidic pH (~4.5–5.0) essential for the activation of hydrolytic enzymes?
Answer: Lysosome
Lysosomes maintain a luminal pH of ~4.5–5.0 via V-type H⁺-ATPase pumps, which is required to activate acid hydrolases for intracellular digestion.