Cellular Structures: Nucleus & Cytology Vocabulary

Vocabulary flashcards covering nucleus, cytoplasm, organelles, and key membrane components based on the provided lecture notes.

Nucleus

Membrane-bound organelle in eukaryotic cells that houses DNA and regulates cellular activities.

Nuclear envelope

Double membrane surrounding the nucleus that contains nuclear pores for transport.

Nuclear pores

Channels in the nuclear envelope that allow selective exchange of molecules between the nucleus and cytoplasm.

Nucleoplasm

The semi-fluid substance inside the nucleus that contains chromatin and the nucleolus.

Nucleolus

Non-membrane-bound region inside the nucleus where ribosome assembly begins.

Chromatin

Uncondensed DNA-protein complex found in non-dividing cells.

Chromosome

Condensed DNA structure visible during cell division.

Multinucleated

Cells containing more than one nucleus.

Anucleate

Cells lacking a nucleus, such as mature red blood cells.

Cytoplasm

Region inside the cell membrane but outside the nucleus, containing cytosol, inclusions, and organelles.

Cytosol

Fluid component of the cytoplasm where many metabolic reactions occur.

Inclusions

Stored materials within the cytoplasm (e.g., granules, pigments).

Organelles

Membrane-bound or non-membrane-bound structures within the cytoplasm with specific functions.

Membrane-bound organelles

Organelles that have their own membranes, separate from the cell membrane.

Non-membrane-bound organelles

Organelles without a surrounding membrane (e.g., ribosomes, cytoskeleton components).

Plasma membrane

Selective, semi-permeable boundary of the cell composed mainly of lipids and proteins.

Phospholipid bilayer

Two layers of phospholipids with hydrophilic heads facing water and hydrophobic tails inside.

Amphipathic

Molecule with both hydrophilic (water-loving) and hydrophobic (water-hating) parts.

Glycolipid

Carbohydrate attached to a lipid on the outer surface of the plasma membrane.

Glycocalyx

Carbohydrate chains on the exterior surface of the cell, involved in cell recognition.

Glycoprotein

Protein with attached carbohydrate chains; important for cell recognition and signaling.

Integral protein

Membrane protein that is fully embedded within the phospholipid bilayer.

Peripheral protein

Membrane protein located on the surface of the membrane, not embedded.

Cholesterol (in membranes)

Lipid molecule within the membrane tails that helps regulate membrane fluidity and stability.

Rough endoplasmic reticulum (RER)

ER studded with ribosomes; site of protein synthesis and initial folding.

Smooth endoplasmic reticulum (SER)

ER without ribosomes; functions include lipid metabolism, detoxification, and calcium storage.

Ribosome

Ribonucleoprotein particle with two subunits (small and large) responsible for protein synthesis; can be free or attached to RER.

Golgi apparatus

Stack of flattened membranes that modifies, sorts, and packages proteins for secretion or delivery to destinations like lysosomes or the plasma membrane.

Lysosome

Membrane-bound organelle containing hydrolytic enzymes for intracellular digestion and autophagy.

Autophagy

Process of self-digestion where damaged organelles are degraded and recycled.

Peroxisome

Membrane-bound organelle that breaks down fatty acids and detoxifies reactive oxygen species; abundant in liver.

Mitochondrion

Double-membrane organelle (with cristae and matrix) that produces ATP; contains its own DNA.

Cristae

Folds of the inner mitochondrial membrane that increase surface area for ATP production.

Matrix

Fluid interior of the mitochondrion where metabolic reactions occur.

Centrosome

Cell center near the nucleus that organizes microtubules; contains a pair of centrioles in animal cells.

Centriole

Nine-triplet microtubule structure; pair forms the centrosome and organizes the mitotic spindle.

Cytoskeleton

Non-membrane-bound network of protein filaments (microfilaments, intermediate filaments, microtubules) that supports shape and transport.

Cilia

Short, numerous projections from a cell used for movement of substances over the cell surface.

Flagellum

Long, single projection (tail) used for cell movement; in humans, sperm cells possess a flagellum.

Microvilli

Dense, short projections that increase the cell’s surface area for absorption, common in the digestive system.