Biology Chapter 4 Vocabulary

52 terms by lpheiner 

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Actin

Muscle protein making up the thin filaments in a sarcomere; its movement shortens the sarcomere, yielding muscle contraction. Actin filaments play a role in the movement of the cell and its organelles.

Adenosine Triphosphate (ATP)

Nucleotide with three phosphate groups. The breakdown of ATP into ADP +P makes energy available for energy-requiring processes in cells.

Adhesion Junction

Junction between cells in which the adjacent plasma membranes do not touch but are held together by intercellular filaments attached to buttonlike thickenings.

Apoptosis

Programmed cell death involving a cascade of specific cellular events leading to the death and destruction of the cell.

Capsule

Gelatinous layer surrounding the cells of blue-green algae and certain bacteria.

Cell

Smallest unit that displays the properties of life; composed of cytoplasm surrounded by a plasma membrane.

Cell Theory

One of the major theories of biology, which states that all organisms are made up of cells; cells are capable of self-reproduction and come only from preexisting cells.

Cell Wall

Structure that surrounds a plant, protistan, fungal, or bacterial cell and maintains the cell's shape and rigidity.

Cellular Respiration

Metabolic reactions that use the energy from carbohydrates, fatty acid, or amino acid breakdown to produce ATP molecules.

Centriole

Cell organelle, existing in pairs, that occurs in the centrosome and may help organize a mitotic spindle for chromosome movement during animal cell division.

Centrosome

Central microtubule organizing center of cells. In animal cells, it contains two centrioles.

Chloroplast

Membrane-bound organelle in algae and plants with chlorophyll-containing membranous thylakoids; where photosynthesis takes place.

Chromatin

Network of fibrils consisting of DNA and associated proteins observed within a nucleus that is not dividing.

Chromosome

Structure consisting of DNA complexed with proteins that transmit genetic information from the previous generation of cells and organisms to the next generation.

Cilia

Short, hairlike projection from the plasma membrane, occurring usually in large numbers

Crista

Short, fingerlike projections formed by the folding of the inner membrane of mitochondria.

Cytoplasm

Contents of a cell between the nucleus (nucleoid) region of bacteria and he plasma membrane.

Cytoskeleton

Internal framework of the cell, consisting of microtubules, actin filaments, and intermediate filaments.

Endomembrane System

Collection of membranous structures involved in transport within the cell.

Endoplasmic Reticulum (ER)

System of membranous saccules and channels in the cytoplasm, often with attached ribosomes.

Eukaryotic Cell

Type of cell that has a membrane-bounded nucleus and membranous organelles; found in organisms within the domain Eukarya.

Extracellular Matrix

Meshwork of polysaccharides and proteins that provides support for an animal cell and affects its behavior.

Fimbriae

In bacteria, small, bristle-like fibers on bacterial cell surface that enables bacteria to adhere to surfaces.

Flagella

Long, slender extension used for locomotion by some bacteria, protozoans, and sperm.

Gap Junction

Junction between cells formed by the joining of two adjacent plasma membranes; it lends strength and allows ions, sugars, and small molecules to pass between cells.

Golgi Apparatus

Organelle consisting of saccules and vesicles that processes, packages, and distributes molecules about or form the cell.

Grana

Stack of chlorophyll-containing thylakoids in a chloroplast.

Lysosome

Membrane-bounded vesicle that contains hydrolytic enzymes for digesting macromolecules.

Matrix

Unstructured semifluid substance that fills the space between cells in connective tissues or inside organelles.

Microtubule

Small, cylindrical organelle composed of tubulin protein around an empty central core; present in the cytoplasm, centrioles, cilia, and flagella.

Mitochondrion

Membrane-bounded organelle in which ATP molecules are produced during the process of cellular respiration.

Nuclear Envelope

Double membrane that surrounds the nucleus in eukaryotic cells and is connected to the endoplasmic reticulum; has pores that allow substances to pass between the nucleus and the cytoplasm.

Nuclear Pore

Opening in the nuclear envelope that permits the passage of proteins into the nucleus and ribosomal subunits out of the nucleus.

Nucleoid

Region of prokaryotic cells where DNA is located; it is not bounded by a nuclear envelope.

Nucleolus

Dark-staining, spherical body in the nucleus that produces ribosomal subunits.

Nucleus

Membrane-bounded organelle within a eukaryotic cell that contains chromosomes and controls the structure and function of the cell.

Organelle

Small, often membranous structure in the cytoplasm having a specific structure and function.

Plasma Membrane

Membrane surrounding the cytoplasm that consists of a phospholipid bilayer with embedded proteins; functions to regulate the entrance and exit of molecules from cell.

Plasmodesmata

In plants, cytoplasmic strands that extend through pores in the cell wall and connect the cytoplasm of two adjacent cells.

Polyribosome

String of ribosomes simultaneously translating regions of the same mRNA strand during protein synthesis.

Prokaryotic Cell

Lacking a membrane-bounded nucleus and organelles; the cell type within the domains Bacteria and Archaea

Ribosomes

RNA and protein in two subunits; site of protein synthesis in the cytoplasm.

Rough ER (Endoplasmic Reticulum)

Membranous system of tubules, vesicles, and sacs in cells; has attached ribosomes.

Secretion

In the cell, release of a substance by exocytosis from a cell that may be a gland or part of a gland; in the urinary system, movement of certain molecules from blood into the distal tubule of a nephron so that they are added to urine.

Sex Pili

In a bacterium, elongated, hollow appendage used to transfer DNA to other cells.

Smooth ER (Endoplasmic Reticulum)

Membranous system of tubules, vesicles, and sacs in eukaryotic cells; lacks attached ribosomes.

Stroma

Fluid within a chloroplast that contains enzymes involved in the synthesis of carbohydrates during photosynthesis.

Surface-Area-To-Volume Ration

Ratio of a cell's outside area to tis internal volume.

Thylakoid

Flattened sac within a granum whose membrane contains chlorophyll and where the light reactions of photosynthesis occur.

Tight Junction

Junction between cells when adjacent plasma membrane proteins join to form an impermeable barrier.

Vacuole

Membrane-bounded sac, larger than a vesicle; usually functions in storage and can contain a variety of substances. In plants, the central vacuole fills much of the interior of the cell.

Vesicle

Small, membrane-bounded sac that stores substances within a cell.

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