Cell: The Unit of Life - Vocabulary Flashcards

This set of flashcards covers the key vocabulary terms related to cell structure and function, as discussed in the provided lecture notes.

Unicellular Organisms

Organisms composed of a single cell capable of independent existence and performing essential life functions.

Multicellular Organisms

Organisms composed of many cells, like humans.

Cell Theory

All living organisms are composed of cells and products of cells and all cells arise from pre-existing cells.

Eukaryotic Cells

Cells that have a membrane-bound nucleus and other membrane-bound organelles.

Prokaryotic Cells

Cells that lack a membrane-bound nucleus.

Cytoplasm

Semi-fluid matrix that occupies the volume of the cell, the main arena of cellular activities.

Organelles

Distinct structures within eukaryotic cells, like the endoplasmic reticulum (ER), Golgi complex, lysosomes, and mitochondria.

Ribosomes

Non-membrane bound organelles found in all cells, responsible for protein synthesis.

Cell Wall

Non-living rigid structure forming an outer covering for the plasma membrane of fungi and plants, providing shape and protection.

Endoplasmic Reticulum (ER)

Network of tubular structures scattered in the cytoplasm of eukaryotic cells, dividing the intracellular space into luminal and extra luminal compartments.

Rough Endoplasmic Reticulum (RER)

Endoplasmic reticulum with ribosomes attached to its outer surface, involved in protein synthesis and secretion.

Smooth Endoplasmic Reticulum (SER)

Endoplasmic reticulum lacking ribosomes, the major site for lipid synthesis.

Golgi Apparatus

Cell organelle that principally performs the function of packaging materials and modifies proteins and lipids.

Lysosomes

Membrane-bound vesicular structures rich in hydrolytic enzymes, involved in digesting macromolecules.

Vacuoles

Membrane-bound spaces in the cytoplasm containing water, sap, excretory products, and other materials.

Mitochondria

Double membrane-bound organelles that are the sites of aerobic respiration and produce cellular energy in the form of ATP.

Plastids

Organelles found in plant cells and euglenoids, bearing pigments and classified into chloroplasts, chromoplasts, and leucoplasts.

Chloroplasts

Plastids containing chlorophyll and carotenoid pigments, responsible for trapping light energy for photosynthesis.

Chromoplasts

Plastids containing fat-soluble carotenoid pigments like carotene and xanthophylls, giving parts of the plant yellow, orange, or red color.

Leucoplasts

Colorless plastids of varied shapes and sizes with stored nutrients like carbohydrates, oils, and proteins.

Cytoskeleton

An elaborate network of filamentous proteinaceous structures consisting of microtubules, microfilaments and intermediate filaments present in the cytoplasm.

Cilia and Flagella

Hair-like outgrowths of the cell membrane involved in cell movement or the movement of surrounding fluid.

Centrosome

Organelle containing two cylindrical structures called centrioles, involved in cell division in animal cells.

Centrioles

Cylindrical structures within the centrosome, forming the basal body of cilia or flagella and spindle fibers during cell division.

Nucleus

Cell organelle containing chromatin, nuclear matrix, and nucleoli that controls cell activities and plays a role in heredity.

Chromatin

Extended and elaborate nucleoprotein fibers within the interphase nucleus, containing DNA, histones, and RNA.

Microbodies

Membrane bound minute vesicles that contain various enzymes.

Cell Membrane

The outer boundary of the cell, composed mainly of lipids and proteins, selectively permeable.

Fluid Mosaic Model

Improved model of the structure of the cell membrane, proposed by Singer and Nicolson (1972).

Passive Transport

Movement of molecules across the membrane without any requirement of energy.

Osmosis

Movement of water across the membrane by diffusion from higher to lower concentration.