General Biology 1st Semester - VOCABULARY Flashcards (Cell Theory & Cell Structures)

Vocabulary flashcards covering key concepts from cell theory, cell structures, tissues, cell division, membranes, enzymes, and related processes as described in the notes.

Cell theory

Principle that all living things are made of cells; the basic unit of life; and new cells arise from preexisting cells.

Cell

The basic unit of life; the smallest unit that can perform all life processes.

Preexisting cell

A cell that exists prior to another cell’s formation; new cells come from division of existing cells.

Robert Hooke

Scientist who used a thin cork slice to observe cells and coined the term 'cell'.

Cork

Thin slice of dead plant used by Hooke to observe cell-like boxes.

Anton van Leeuwenhoek

Pioneer who built a simple microscope and first observed microorganisms (1673).

Compound microscope

Early microscope with multiple lenses, enabling higher magnification.

Omnis cellula e cellula

Latin phrase meaning 'all cells come from preexisting cells.'

Zacharias Janssen

Inventor of the first compound microscope.

Energy flow

Concept in the modern cell theory that energy transfer happens within cells.

DNA

Genetic material carried by cells and passed from cell to cell during division.

Organelles

“Little organs” inside the cell that perform specific functions.

Cell membrane

Thin, double-layered boundary of the cell made of phospholipids and proteins; regulates passage of materials.

Phospholipid

Major component of the cell membrane with a hydrophilic head and hydrophobic tail.

Cell wall

Rigid layer surrounding plant cells that provides protection and structure.

Nucleus

Membrane-bound organelle that houses DNA and regulates cell activities.

Ribosome

Protein-RNA complex; site of protein synthesis; not membrane-bound.

Mitochondria

Double-membrane organelle with own DNA; powerhouse of the cell producing ATP.

Endoplasmic Reticulum (Rough)

ER with ribosomes; site of protein synthesis.

Endoplasmic Reticulum (Smooth)

ER without ribosomes; lipid synthesis and other reactions.

Golgi body

Organelle that sorts, tags, packages, and ships proteins and lipids.

Lysosome

Organelle that digests nutrients and worn-out organelles.

Chloroplast

Site of photosynthesis in plant cells.

Vacuole

Membrane-bound sac that maintains water balance and stores substances.

Cytoskeleton

Network of fibers that gives the cell its shape and enables movement.

Vesicle

Small, membrane-bound transport container within the cell.

Eukaryotic cell

Cell with a nucleus and membrane-bound organelles; includes plants, animals, fungi, and protists.

Prokaryotic cell

Unicellular organism lacking a nucleus and membrane-bound organelles; includes Archaea and Bacteria.

Tissue

Group of similar cells performing a common function.

Epithelial tissue

Tissue that lines cavities and glands; protective and/or absorptive.

Connective tissue

Tissue that binds, supports, or separates other tissues; develops from mesoderm.

Nervous tissue

Tissue composed of neurons and glial cells that transmits impulses.

Muscular tissue

Tissue specialized for movement; includes skeletal, smooth, and cardiac types.

Adipose tissue

Fat-storing tissue that provides energy storage and insulation.

Fibrous connective tissue

Tissue with dense fibers; includes tendons and ligaments.

Cartilage

Rigid connective tissue with collagen and proteoglycans providing support.

Bone

Osseous tissue containing osteocytes; supports and protects body structures.

Blood

Fluid connective tissue containing plasma, red and white cells, and platelets.

Red blood cell (erythrocyte)

Cell that carries oxygen via hemoglobin; disk-shaped and flexible.

White blood cell (leukocyte)

Immune cells that defend against pathogens; include various subtypes.

Lymphocytes

White blood cells with large nuclei; key role in immune response.

Phagocytes

White blood cells that engulf and destroy bacteria.

Ciliated epithelial cell

Epithelium cell with cilia that traps and moves debris in airways.

Nerve cell

Neuron; transmits electrical impulses in the nervous system.

Muscle cell

Muscle fiber rich in mitochondria; enables contraction and movement.

Sperm

Male gamete; carries paternal DNA.

Egg

Female gamete; carries maternal DNA; forms embryo.

Root hair cell

Plant cell that absorbs water and minerals; many mitochondria; no chloroplasts.

Palisade cell

Leaf cell rich in chloroplasts; specialized for photosynthesis.

Xylem vessel

Water-conducting cell in the vascular system; lacks end walls and organelles.

Parenchyma

Alive plant tissue involved in storage and photosynthesis; bulk tissue.

Collenchyma

Plant tissue with thickened, living cell walls providing support.

Sclerenchyma

Plant tissue with thick, lignified walls; usually dead at maturity for support.

Xylem

Vascular tissue that transports water and minerals; provides support.

Phloem

Vascular tissue that distributes sugars and nutrients.

Epidermal

Dermal tissue that covers plants; protects against water loss.

Guard cells

Specialized epidermal cells that regulate stomatal openings for gas exchange.

Cell division

Process by which a parent cell divides to form daughter cells.

Interphase

Cell cycle phase where growth, DNA replication, and metabolism occur.

G1

First growth phase; cell grows and prepares to synthesize DNA.

S

Synthesis phase; DNA replication occurs.

G2

Second growth phase; cell prepares for mitosis.

Chromatin

Uncondensed DNA-protein complex inside the nucleus.

Chromosome

Condensed structure of DNA and proteins visible during division.

Chromatid

Identical copy of a replicated chromosome.

Centromere

Region where sister chromatids are held together and where kinetochores attach.

Centriole

Organelle that organizes spindle fibers during cell division.

Mitotic spindle

Microtubule structure that separates chromosomes during mitosis.

Prophase

Early mitosis; chromatin condenses, centrosomes move apart; nucleolus disappears.

Metaphase

Chromosomes align at the cell equator; spindle fibers attach to kinetochores.

Anaphase

Sister chromatids separate and move to opposite poles.

Telophase

Nuclei form at poles; chromosomes de-condense.

Cytokinesis

Division of cytoplasm; results in two separate daughter cells.

Meiosis

Cell division that produces four haploid gametes; introduces genetic variation.

Prophase I

Meiosis I stage where homologous chromosomes pair and crossing over occurs.

Crossing over

Exchange of genetic material between homologous chromosomes, increasing variation.

Chiasma

Visible crossover point between homologous chromatids during meiosis.

Homologous chromosomes

Chromosome pairs of similar size and gene loci that pair during meiosis.

Tetrad

Group of four chromatids (two homologous chromosomes) formed during meiosis I.

Metaphase I

Homologous chromosome pairs align at the equator in meiosis I.

Anaphase I

Homologous chromosomes separate and move to opposite poles in meiosis I.

Telophase I

Two haploid cells form; nuclei reassemble and chromosomes condense.

Prophase II

Meiosis II stage; chromosomes condense and spindle forms in each cell.

Metaphase II

Chromosome centromeres align at the equator in each cell.

Anaphase II

Sister chromatids separate and move to opposite poles.

Telophase II

Nuclei form around chromosomes; four haploid daughter cells result.

Fluid mosaic model

Membrane model describing a phospholipid bilayer with embedded proteins in a dynamic arrangement.

Phospholipid bilayer

Two-layer arrangement of phospholipids forming the cell membrane's basic structure.

Hydrophilic

Water-loving head of a phospholipid molecule.

Hydrophobic

Water-fearing tail of a phospholipid molecule.

Cholesterol

Sterol molecules interspersed in the membrane to modulate fluidity.

Glycoprotein

Transmembrane protein with carbohydrate chains; involved in cell recognition.

Receptor protein

Membrane protein that binds signaling molecules to initiate cellular responses.

Globular protein

Protein that aids in transport across membranes via facilitated diffusion.

Osmosis

Diffusion of water across a selectively permeable membrane.

Aquaporin

Water channel protein that facilitates osmosis.

Endocytosis

Process of transporting material into the cell by vesicle formation.

Phagocytosis

Endocytosis process where cells engulf large particles or microbes.

Pinocytosis

Endocytosis process where cells engulf liquids and dissolved substances.

Enzymes

Proteins that act as biological catalysts to speed up chemical reactions.