Cell Functions Chapter 2 and 3

kms013's version from 2015-09-23 19:33

Section 1

Question Answer
Signal transductionactivating a series of intracellular intermediaries producing changes in either cytoplasm, mucleus, or both
Hydrophobic signlaing moleculessuch as steroids and thyroid hormones...bind reversibly to carrier protiens in the plasma for transport through the body
plasma membranephosphlipid bilayer containing cholesterol and proteins (integral and peripheral) and some carbohydrates (externally); FUNCTIONS forms a SPM; acts as 1. physical barrier 2. regulates material into and out of cell 3. keeps electrical charge difference across the PM 4. functions in cell communication
Ciliashort; numerous membrane extensions supported by microtubles, which occur on the exposed membrane surfaces of some cells; FUNCTION: Move substances (mucous and dissolved materials) over cell surface
FlagellumLong, singular membrane extension supported by microtubules; presented on sperm cells; FUNCTION: propels sperm
MicrovilliNumerous thin membrane folds projecting from the free cell surface; supported by microfilaments: FUNCTION: Increase membrane SA for greater absorption
NucleusLarge structure enclosed within a double membrane; contains chromatin, nucleolus, and nucleoplasm; FUNCTION: houses the DNA that serves as the genetic material for directing protein synthesis
Nuclear EnvelopeDouble membrane boundary b/w cytoplasm and nuclear contents; continuous with rER; FUNCTION: separates nucleus from cytoplasm
Nuclear PoresOpenings through the nuclear envelope; FUNCTION: Allow passage of materials b/w the cytoplasm and nucleoplasm including RNA, proteins, ions, and small water-soluble molecules
NucleolusLarge, prominent structure within the nucleus; FUNCTION: Functions in synthesis of ribosomes; houses ribosomes and rDNA; where rDNA transcription and ribosomal subunits assemble
CytoplasmContents of cells b/w the PM and nuclear envelope; FUNCTION: Responsible for many cellular processes
CytosolViscous fluid medium with dissolved solutes (ios, proteins, carbohydrates, lipids) FUNCTION: Provides support for organelles; serves as the viscous fluid medium through which diffusion occurs
OrganellesMembrane-bound and non-membrane bound structures; FUNCTION: Carry out specific metabolic activities of the cell
rERExtensive interconnected membrane network that varies in shape (cisternae tubules); ribosomes attached on cytoplasmic surface; prominent in cells specialized in protein secretion; sacliek and parallel; stacks of cisternae; FUNCTION: Modifies, transports, and stores proteins produced by attached ribosomes; these proteins are secreted, become components of the PM or serve as enzymes or lysosomes
sERExtensive interconnected membrane network lacking ribosomes; lipid biosynthesis;FUNCTION: sythesizes, transports, and stores lipids (steroids); metabolizes carbohydrates; detoxifies drugs, alcohol, and poisions; forms vesicles and peroxisomes; temporary Ca2+ sequestration
RibosomesOrganelles composed of both protein and ribosomal RNA that are organized into both a large and small subunit; may be bound to a membrane or free in cytosol; FUNCTION: Engage in protein sythesis; bound ribosomes produce prteins that are secreted, incorporated into PM and within lysosomes; free ribosomes produced protiens used within the cell
cell differentiationprocess by which cells of an embryo become specialized structurally to augment specific cytoplasmic activites for functions at the level of tissues and organs
ERconvoluted network of membrane enclosing continuous spaces called cisternae and extending from the nucleus to the PM
cisternaeseries of intercommunicating channels and sacs in ER
Golgi Apparatusorganelle with stacked membranous cisternae that modifies, packs, and sorts materials that arrive from the ER in transport vesicles; forms secretory vesicles and lysosomes
transport vesiclesmembrane enclosed carriers; proteins in transport vesicles enter the cis or recieving face of the Golgi, move through medical cisternae of the Golgi network for enzymatic modifcations, and are released in other vesicles at the trans face
Lysosomespherical-shaped membrane-bound organelles formed from the Golgi apparatus; contain digestive enzymes; FUNCTION: Digest cirobes or materials (ingested by cell, worn-out cellular components, or the entire cell)
Mitochondriamajor site of ATP synthesis and are abundant in cells or cytoplasmic regions where large amounts of energy are expended; Outer membrane contains thransmembrane proteins (porins), Inner membrane- many folds called cristae (increase SA) enclosing a gel-like matrix; the inner membrane includes enzyme assemblies of electron-transport system and ATP synthase; FUNCTION: Synthesize most ATP during aerobic cellular respiration by digestion of fuel molecules (glucose) in the presence of O2; also, mitochondria of stressed cells may release cytochrome c from the inner membrane, triggering a regulated series of events culminating in cell death (apoptosis)
intermembrane spacemitochondria has 2 separate and very different membranes: Innermost matrix and narrow intermembrane space: both contain a higher density of protein molecules than other membranes in the cell and have reduced fluidity
MicrotubulesHollow cylinders composed of tubulin protien: FUNCTIONS: Maintain cell shape and rigidity; organize and move organelles; support cilia and flagella; participate in vesicular transport; separate chromosomes during cell division; tracks for transport of vesicles and organelles by the motor proteins kinesin and dynein
cytoskeletonorganized network of protein filaments and hollow tubules; including microfilaments, intermediate filaments, and microtubules; FUNCTION: maintain intracellular structural support and organization of cells; participates in cell division; facilitates movement
Microfilaments (actin Filaments)Actin protein monomers organized into two thin, interwined protein filaments (actin); FUNCTION:Provide strutural support; stabilize junctions b/w cells; important in changing cell shape during cell division, locomotion, and change of cells SA; give direction to a cells crawling movment; more flexible than microtubules
Intermediate filamentvarious protein components: FUNCTION: Provide structural support; stabilize junctions b/w cells
apoptosisRole of mitochondria; occurs at times of cell stress when cytochrome c is released from the intermembranous space in the cytoplasm activating sets of proteases that degrade al the cellular components; "rapid cell death"
"cell suicide" vs. apoptosisCell suicide is cell death not because of injury, but because of factors within the cell that determine this route; lysosomes start killing substances in cell and degradation occurs
chromatincombination of DNA and its associated proteins
histonesproteins that DNA wraps around to form nucleosomes (beads on a string)
mitosiscell division where a parent cell divides and each of the two daughter cells receives a chromosonal set identical to that of the parent cell: 2 diploid cells: IPMAT
Interphasethe long growht period between mitoses; cell is normal and doing its job
prophase1st stage of mitosis; when the chromosomes condense, the nuclear envelope disassembles, and the microtubular spindle forms
metaphase2nd stage of mitosis: when chromosomes are aligned
anaphase3rd stage of mitosis: when the chromosomes begin to separate toward the two centrosomes
telophase4th stage of mitosis: when nuclear envelope re-forms around the separated chromosomes; ends with cytokinesis or cell cleavage into two daughter cells by a contractile ring of actin filaments and myosin.
stem cellsoccur in all tissues with rapid cell turnover; allow creation of more cells
Embryonic stem celleventually decides what the cells become
meiosisporcess by which two successive cell divisions produce cells called GAMETES containing half the number of chromosomes found in somatic cells
gameteSex cells---sperm and egg cells
haploidhaving just one chromosome from each pair present in the body's somatic cells; having 1/2 the number of chromosomes (23 not 46)...during meiosis II, turns into haploid; the union of haploid eggs and sperm at fertilization forms a new diploid cell (the zygote) that can develop into a new individual
crossoverDurig a synapsis (chromosomes coming together) double stranded breaks and repairs occur in the DNA, some of which result in reciprocal DNA exchanges called crossovers
nucleosomestructure that produces the initial organization of free double-stranded DNA into chromatin
histologystudy of tissues
cytologystudy of cells; a single cell and individual characteristic of that cell; have to know normal cell to know an abnormal

Section 2