Cell Structure and Functions – Lecture Notes

Vocabulary flashcards covering major terms related to cell structure, organelles, cell types, and key scientists from the lecture notes.

The smallest, basic unit of life responsible for all life processes.

Cell

Robert Hooke

Scientist who first discovered and named the cell.

Anton van Leeuwenhoek

Observed living cells with a higher-magnification compound microscope.

Robert Brown

Scottish botanist who discovered the nucleus of the cell.

Unicellular Organism

An organism composed of a single cell (e.g., Euglena, Paramecium, yeast).

Multicellular Organism

An organism made up of more than one cell (e.g., plants and animals).

Micrometer (µm)

Unit of measurement commonly used to express cell size.

Ovum Cell

The largest human cell (~120 µm in diameter).

Nerve Cell

The longest human cell (can reach ~1 m in length).

Sperm Cell

The smallest human cell (~5 µm long).

Plasma (Cell) Membrane

Thin, selectively permeable layer that encloses the cell, giving shape and flexibility.

Cell Wall

Rigid outer covering of plant cells that provides additional support and protection.

Cytoplasm

Semi-fluid matrix surrounding the nucleus in which organelles are suspended.

Endoplasmic Reticulum (ER)

Network of membrane-bound channels acting as an intracellular transport system.

Rough ER

ER studded with ribosomes; synthesizes and transports proteins.

Smooth ER

ER lacking ribosomes; synthesizes lipids and detoxifies substances.

Golgi Apparatus

Series of flattened sacs that process, package, and sort secretory materials.

Mitochondrion

Powerhouse of the cell that generates ATP through oxidative metabolism.

Lysosome

Membrane-bound organelle containing enzymes that digest pathogens and worn-out parts.

Ribosome

Complex of proteins and RNA that synthesizes proteins.

Centrosome

Organelle that produces microtubules and contains a pair of centrioles in animal cells.

Centriole

Small cylindrical structure of microtubules aiding in cell division.

Cytoskeleton

Network of protein fibers providing cell shape, strength, and motility.

Microtubule

Long protein tube forming the spindle apparatus during cell division.

Microfilament

Thin protein filament that supports cell shape and aids movement.

Nucleus

Double-membraned organelle storing DNA and coordinating cellular activities.

Nuclear Envelope

Double membrane that separates the nucleus from the cytoplasm and continues with ER.

Nucleoplasm

Dense, protein-rich substance filling the nucleus.

Nucleolus

Nuclear structure rich in RNA and proteins; site of ribosome formation.

Nuclear Pore

Opening in the nuclear envelope that regulates exchange between nucleus and cytoplasm.

Chromatin

Complex of DNA and proteins that condenses into chromosomes during cell division.

ATP (Adenosine Triphosphate)

Energy currency produced mainly in mitochondria for cellular activities.

Selective Permeability

Property of membranes to allow certain substances to pass while restricting others.

Biconcave Shape

Form of human red blood cells that facilitates passage through capillaries.