BIO101 LEC Lesson 2: Cell Structure and Function - VOCABULARY Flashcards

Vocabulary flashcards covering key terms related to cell structure, organelles, membranes, transport mechanisms, and basic genetics from Lesson 2 notes.

Cell

The basic unit of life; contains organelles that perform cellular functions.

Prokaryote

A single-celled organism that lacks a nucleus (e.g., bacteria).

Eukaryote

Organisms with cells that have a nucleus and membrane-bound organelles.

Nucleus

Command center of the cell; contains DNA; site of RNA synthesis.

Nuclear envelope

Double membrane surrounding the nucleus; contains nuclear pores.

Nuclear pore

Channels in the nuclear envelope that regulate transport into and out of the nucleus.

Nucleolus

Region inside the nucleus where ribosomal subunits are assembled.

Nucleoplasm

Fluid within the nucleus, surrounding the chromatin.

Cytoplasm

Region of the cell outside the nucleus; contains cytosol and organelles.

Cell membrane

Plasma membrane; outer boundary of the cell; selectively permeable.

Phospholipid bilayer

Two-layer membrane of phospholipids forming the barrier of the cell.

Hydrophobic

Water-fearing region; nonpolar tails of phospholipids.

Hydrophilic

Water-loving region; polar heads of phospholipids.

Cholesterol

Sterol in the membrane that adds stability and regulates fluidity.

Membrane proteins

Proteins in the membrane that function as channels, carriers, or receptors.

Receptor molecules

Proteins on the cell surface that bind specific substances to trigger responses.

Ribosome

Molecular machine that synthesizes proteins; can be free or attached to rough ER.

Rough Endoplasmic Reticulum

ER with ribosomes; major site of protein synthesis.

Smooth Endoplasmic Reticulum

ER without ribosomes; major site of lipid synthesis.

Golgi apparatus

Modifies, packages, and distributes proteins and lipids; forms secretory vesicles.

Secretory vesicles

Vesicles that carry substances from the Golgi to the cell membrane for release.

Lysosome

Vesicle with enzymes that digest waste and foreign material; cell garbage collector.

Peroxisome

Organelle that digests fatty acids and hydrogen peroxide.

Mitochondrion

Powerhouse of the cell; site of ATP production via cellular respiration.

ATP

Adenosine triphosphate; main energy currency of the cell.

Cytoskeleton

Internal framework of the cell that supports the cytoplasm and organelles.

Microtubule

Hollow tubes that move organelles and form the spindle during cell division.

Microfilament

Actin filaments involved in maintaining and changing cell shape.

Intermediate filament

Filaments providing mechanical support for the cell.

Centrioles

Paired microtubule structures in the centrosome; organize spindle during division.

Centrosome

Microtubule-organizing center near the nucleus in animal cells.

Cilia

Short hair-like projections that move substances across cell surfaces.

Flagella

Long whip-like extension that propels sperm and some cells.

Microvilli

Finger-like extensions that increase surface area for absorption.

Cell wall

Rigid boundary of plant cells outside the cell membrane.

Diffusion

Passive transport where solutes move from high to low concentration.

Osmosis

Diffusion of water across a selectively permeable membrane.

Concentration gradient

Difference in solute concentration; drives diffusion from high to low.

Isotonic

Solution with the same solute concentration as the cell; no net water movement.

Hypotonic

Solution with lower solute concentration; water enters the cell.

Hypertonic

Solution with higher solute concentration; water leaves the cell.

Carrier-mediated transport

Transport using membrane proteins (carriers) to move substances.

Facilitated diffusion

Carrier-mediated diffusion down a concentration gradient without energy.

Active transport

Carrier-mediated transport against a gradient; requires ATP.

Endocytosis

Process of taking substances into the cell via vesicles.

Exocytosis

Release of materials from the cell via vesicles fusing with the membrane.

Endocytosis subtypes

Phagocytosis = solid particles; Pinocytosis = liquids.

Gene expression

Process by which genetic information directs protein synthesis.

DNA

Deoxyribonucleic acid; genetic material organized as a double helix.

RNA

Ribonucleic acid; involved in transcription and translation for protein synthesis.

Chromosome

Tightly coiled DNA molecule that carries genetic information during division.

Chromatid

One copy of a replicated chromosome; held to the other by a centromere.

Chromatin

Uncoiled DNA and proteins; chromosomes loosely arranged before division.

Gene

A sequence of nucleotides that codes for a specific protein.

DNA double helix

Two DNA strands wound around each other forming a double helix.

36 trillion cells

Approximately the number of cells in the human body.

Neurons

Longest cells in the body; also among the longest-living cells.

Sperm cell

Smallest cell in the human body.

Egg cell

Largest cell in the human body.

Red blood cells (RBCs)

Live about 120 days; essential for oxygen transport.

White blood cells (WBCs)

Live about 13 days; part of the immune system.