Chapter 3 - Cells Flashcards
cytoplasm
a thick solution that fills each cell and is enclosed by the cell membrane
organelle
specialized structures within a cell
nucleus (biology)
a large, membrane-bound structure in most cells that contains the genetic code
three main parts of a cell
plasma membrane, cytoplasm, nucleus
plasma membrane
a membrane that surrounds the entire cell, forming its outer boundary; it is made up of phospholipids and cholesterol
hormone
a regulatory substance produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action
cytoskeleton
a microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence
ribosome
a minute particle consisting of RNA and associated proteins found in large numbers in the cytoplasm of living cells; it helps with protein synthesis
endoplasmic reticulum (ER)
a network of membranes inside a cell through which proteins and other molecules move, made of two types: rough ER and smooth ER
rough ER
part of endoplasmic reticulum that receives, folds, and transports newly made proteins
smooth ER
part of endoplasmic reticulum that creates the membrane for the cell
Golgi apparatus
a complex of vesicles (pouches) and folded membranes within the cytoplasm of most eukaryotic cells, involved in secretion (e.g. mucus) and intracellular transport
mitochondrion
an organelle in the cell that produces energy for the cell (e.g. ATP)
lysosome
the part of the cell that digests nutrients and helps to destroy harmful microbes
centrosome
an organelle in the cell that organizes microtubules; involved in the process of cell division
microtubule
a microscopic tubular structure present in numbers in the cytoplasm of cells, sometimes aggregating to form more complex structures
centriole
a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division
microvilli
small, fingerlike projections of the plasma membrane of some cells; these projections increase the surface area of the cell and thus increase its ability to absorb substances.
cilia
extremely fine, hairlike extensions on the exposed or free surfaces of cells; they allow the cell to sense its surroundings, can be used to move things, and in taste buds they help people taste food
flagellum
a single projection extending from the cell surface; a major example is the tail in a human sperm cell, which propels it forward
nuclear envelope
a highly regulated membrane barrier that separates the nucleus from the cytoplasm
nuclear pore
holes in the nuclear envelope that permit large molecules to move into and out of the nucleus
nucleoplasm
a special type of cell material in the nucleus that contains a number of structures, the two most important being the nucleolus and the chromatin granules
nucleolus
a dense region of the nuclear material that is critical in protein formation because it is where the cell makes the subunits that form ribosomes
chromatin granules
a complex of DNA and protein found in eukaryotic cells; the primary function is to package long DNA molecules into more compact, denser structures
chromosome
a long DNA molecule with part or all of the genetic material of an organism
active transport
the mass movement of substances into and out of cells that requires the use of energy (ATP)
passive transport
the mass movement of substances into and out of cells that through a method that does not require energy (e.g. osmosis, diffusion, or filtration)
filtration
in the context of cells it refers to the movement of water and small solute particles, but not larger particles, through a filtration membrane; movement occurs from an area of high pressure to an area of low pressure
crenation
a process resulting from osmosis in which red blood cells, in a hypertonic solution, undergo shrinkage and acquire a notched (a small cut or nick in something) or scalloped (having an edge or border marked with semicircles) surface
lyse
(verb) undergo or cause to undergo lysis
lysis
the breaking down of the membrane of a cell
dialysis
a process where some solutes move across a selectively permeable membrane by diffusion and other solutes do not; this also explains how dialysis machines work in people with kidney failure (by selectively removing waste)
phagocytes
a type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles
pinocytosis
an active transport mechanism used to incorporate fluids or dissolved substances into cells by trapping them in a pocket of plasma membrane that pinches off inside the cell
gene
the basic physical and functional unit of heredity. Genes are made up of DNA.
genome
the complete set of genes or genetic material present in a cell or organism
genomics
the branch of molecular biology concerned with the structure, function, evolution, and mapping of genomes
proteomics
the study of all the proteins produced by an organism
mitosis
a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth
interphase
the period of the cell cycle during which the nucleus is not undergoing active cell division
genetic counselors
people who use principles of genetics to advise clients who wish to produce offspring but are worried about possible genetic disorders
genetic engineers
people who develop ways to manipulate the genetic code to produce a variety of therapies and enhanced biological characteristics of agricultural products
genomics scientists
people who analyze the genetic codes of organisms to help us better understand structure and function, which may lead to better treatments for genetic disorders
stem cell
the body’s raw materials — cells from which all other cells with specialized functions are generated
spindle fibers
microscopic protein structures that help divide genetic material during cell division; they also help organize cellular components
