Cellular Structure and The Cell Cycle Flashcards
cytology
study of cells
cell theory
- all living organisms are made of one or more cells
- cells are basic structural and functional units
- all activities of organism stem from activities of its constituent cell
- all cells arise from preexisting cells
squamous
thin flat scaly shaped often with bulge where nucleus is
cuboidal
squarish looking in frontal section, equal height and width
columnar
distinctly taller than wide
polygonal
irregular angular shapes with 4,5 or more sides
stellate
multiple pointed processes projecting from cell
spheroidal/oval
round to oval
discoidal
disc shaped
fusiform
spindle shaped, elongated with think middle and tapered ends
fibrous
long, slender and threadlike
micrometer
one millionth of a meter
cytoplasm
fluid between the nucleus and surface membrane
plasma membrane
made of proteins and lipids, surrounds the cell
cytosol/intracellular fluid
cell juice, holds cytoskeleton, organelles and inclusions
extracellular fluid
body fluids not contained in cells
tissue fluid
ECF located amid the cells
cytoskeleton
network of protein filaments and cylinders that structurally support a cell, determine its shape, organize its contents, direct the movement of materials within cell and contribute to movements of the cell as a whole
microfilaments
made of protein actin
-concentrated in fibrous mat call terminal web, provides physical support
-form supportive cones of the microvilli and play role in cell movement
intermediate filaments
more stiff, give cell its shape, resits stress and form junctions that attach cells
microtubules
cylinders made of 13 parallel strands (protofilaments)
-hold organelles in place, form bundles to maintain cell shape and rigidity, act as monorail tracks for motor proteins
organelles
organs of the cell
nucleus
largest organelle, contains cells chromosomes, genetic control center of the cell
nuclear envelope
double membrane that encloses nucleus
nuclear pores
holes in nuclear envelope formed by ring of proteins, regulate molecular traffic through envelope
nucleoplasm
material in the nucleus - chromatin, nucleoli
endoplasmic reticulum
system of interconnected channels enclosed by a unit membrane, synthesizes steroids/lipids, detoxifies alcohol/drugs and manufactures most membranes
rough ER
parallel flattened sacs covered with ribosomes
- produces phospholipids and proteins
smooth ER
more tubular, branches more extensively and lack ribosomes
-engage in detox, synthesize stride hormones, store/release calcium and synthesis lipids
ribosomes
small granules of protein and RNA in nucleoli, cytosol, mitochondria, and surfaces of rough ER and nuclear envelope
-read coded messages, mRNA, and assemble amino acids into proteins
-make enzymes and other proteins
Golgi complex
small system of cisterns that synthesize carbs and put finishing touches on protein and glycoprotein synthesis
lysosome
package of enzymes bounded by a membrane
- hydrolyze proteins, nucleic acids, complex carbs, phospholipids and other substrates
autophagy
when lysosomes digest and dispose of surplus or nonfatal organelles and other cell components in order to recycle their nutrients to more important cells
autolysis
digestion of surplus cells by their own lysosomal enzymes
peroxisomes
resemble lysosomes but contain different enzymes
- use oxygen to oxidize organic molecules, produces hydrogen peroxide and then used to oxidize other molecules
proteasomes
hollow cylindrical complexes of proteins located in cytoplasm and nucleus
-helps with protein disposal
mitochondria
specialized for synthesizing ATP, energy is extracted from compounds and transferred to ATP
centrioles
short cylindrical assembly of microtubules
-9 groups of 3 each
- play role in cell division
centrosome
small patch of cytoplasm containing pair of perpendicular centrioles
inclusions
-accumulated cell products like glycogen granolas, pigments, oil droplets
or
- foreign bodies such as viruses/bacteria
G1, first gap
between cell division and DNA replication
- synthesizes proteins, grows and carries out preordained tasks for body
S, synthesis phase
makes duplicate copy of centrioles and nuclear DNA
G2, second gap
between DNA replication and cell division
-exhibits further growth, makes more organelles, finishes replicating centrioles and synthesizes enzymes that control cell division
M, mitotic phase
replicates nucleus, pinches in 2 to form n ew daughter cells
mitosis
mechanism of cell division
prophase
chromosomes condense and nuclear envelope breaks down, spindle fibers grow from centrioles and centrioles migrate to opposite sides
metaphase
chromosomes lie along midline of cell, spider fibers start to attach
anaphase
centromeres divide in 2, chromatids get pulled apart
telophase
chromosomes gather at each pole of cell and decondense, nuclear envelop appears, new nucleoli appear, cleavage furrow appears
cytokinesis
division of cytoplasm into 2 cells
contact inhibition
cessation of cell division in response to contact with other cells
cyclins and cyclin dependent kinases
key elements of molecular timer, rise during interphase and levels falls at end of miomeretosis
- control replication of DNA, and centrioles, condensation of chromosomes, breakdown of envelope, formation of spindle and attachment of chromosomes, splitting of central
