Cell Structure and Functions – Vocabulary Flashcards (General Biology 1, University of Makati, A.D. 1972)

A comprehensive set of vocabulary flashcards covering core terms related to cell structure and functions as described in the notes.

Cell

The basic unit of life; building blocks of living things; a microscopic membrane-bound system that controls the chemicals and molecules needed for an organism; differences between unicellular and multicellular forms.

Cell membrane

Outermost boundary of the cell; gatekeeper that regulates entry and exit; phospholipid bilayer; semi-permeable.

Cytoplasm

Region inside the cell where organelles reside; cytosol is the liquid portion; contains enzymes; cytoskeleton helps maintain cell structure.

Cytoskeleton

Network of protein filaments and microtubules in the cytoplasm; supports cell shape, intracellular organization, and movement.

Cytosol

Fluid portion of the cytoplasm; contains enzymes.

Endoplasmic Reticulum (ER)

Membrane network involved in transport and synthesis; two types: Rough ER (with ribosomes) and Smooth ER (without ribosomes).

Rough Endoplasmic Reticulum (RER)

ER with ribosomes; synthesizes and modifies proteins.

Smooth Endoplasmic Reticulum (SER)

ER without ribosomes; synthesizes fatty acids and phospholipids.

Ribosome

Site of protein synthesis; can be free in cytoplasm or bound to RER.

Free ribosome

Ribosome floating in cytoplasm; synthesizes proteins for use inside the cell.

Bound ribosome

Ribosome attached to RER; synthesizes proteins for secretion or for lysosomes.

Nucleus

Control center of the cell; contains genetic material; enclosed by a nuclear envelope with pores and contains the nucleolus.

Nuclear envelope

Double-membrane surrounding the nucleus; contains nuclear pores.

Nuclear pore

Perforations in the nuclear envelope that regulate movement of molecules between the nucleus and cytoplasm.

Nucleolus

Region within the nucleus where RNA and ribosomal proteins assemble to form ribosomes.

Chromatin

Uncondensed DNA–protein complex inside the nucleus.

Chromosome

Rod- or thread-like structure carrying genes; condensed DNA during cell division.

Nucleoplasm

Fluid inside the nucleus (nucleoplasm) containing DNA, RNA and proteins.

Mitochondrion

Powerhouse of the cell; site of cellular respiration; produces ATP.

Golgi apparatus

Organelle that modifies, sorts, and packages macromolecules for secretion or delivery to other organelles.

Lysosome

Digestive organelle; contains enzymes; digests waste; may self-destruct to protect the cell (suicide bag).

Vacuole

Fluid-filled vesicle that stores chemicals; plant cells have a large central vacuole; both plant and animal cells have vacuoles.

Central vacuole

Large central vacuole in plant cells that stores water and waste.

Chloroplast

Site of photosynthesis in plants and some protists; contains chlorophyll; has outer and inner membranes, thylakoids, granum, and stroma.

Thylakoid

Membrane-bound sacs inside chloroplasts where light reactions occur.

Granum

Stack of thylakoids within a chloroplast.

Stroma

Fluid surrounding the thylakoids inside the chloroplast where the dark reactions occur.

Plastids

Family of plant organelles including chloroplasts, chromoplasts, and leucoplasts.

Chromoplast

Pigment-containing plastid giving color to fruits and flowers (carotenoids).

Leucoplast

Colorless plastid storing starch, oils, and proteins.

Plasmodesmata

Channels through plant cell walls that connect adjacent plant cells.

Plant cell

Cell type with cell wall, chloroplasts, and a large central vacuole; nucleus often at the periphery; plasmodesmata present.

Animal cell

Cell type lacking cell wall and chloroplasts; contains lysosomes and centrioles.

Cell wall

Rigid outer layer outside the cell membrane; present in plants and some bacteria; provides support and protection (often primary and secondary walls in plants).

Pili

Hair-like appendages on bacteria used for attachment to surfaces.

Capsule

Outer protective layer around some bacteria that aids in protection and attachment.

Nucleoid

Region in bacteria where the circular DNA chromosome resides; not membrane-bound.

Plasmid

Small circular DNA molecule separate from chromosomal DNA; carries genes and can be transferred between bacteria.

Mesosome

Folding of the bacterial plasma membrane; observed in some descriptions as a site of respiration and division (often considered an artifact).

Flagellum

Long whip-like organelle that enables bacterial movement.

Cilia

Short, hair-like projections used for movement or sensing the environment.

Microvilli

Finger-like extensions that increase the surface area of the cell membrane for absorption.

Tight junction

Junction that seals space between adjacent cells to limit passage of molecules.

Desmosome

Anchoring junction providing strong adhesion between cells.

Gap junction

Intercellular channels that allow passage of ions and small molecules between cells.

Prokaryotic cell

Cell with no defined nucleus or membrane-bound organelles; circular chromosome; found in bacteria; cell wall present.

Eukaryotic cell

Cell with a true nucleus and membrane-bound organelles; structurally more complex.

Chlorophyll

Green pigment in chloroplasts that captures light energy for photosynthesis.

Photosynthesis

Process by which chloroplasts convert light energy, CO2, and water into glucose and oxygen; involves light reactions and dark reactions (Calvin cycle).

Light reactions

Stage of photosynthesis in which light energy is captured and converted to chemical energy (ATP and NADPH) with oxygen released.

Dark reaction (Calvin cycle)

Stage of photosynthesis that uses ATP and NADPH to synthesize glucose from CO2.

ATP

Adenosine triphosphate; the cell’s energy currency.

NADPH

Nicotinamide adenine dinucleotide phosphate; electron carrier used in photosynthesis.

DNA

Deoxyribonucleic acid; genetic material containing the code for organisms.

RNA

Ribonucleic acid; roles in transcription and translation to produce proteins.

Gene

Basic unit of heredity; specific sequence of DNA or RNA that encodes a product.