chapter 3-cellular organization Flashcards
cytology
study of cells
cytosol
fluid part of the cytoplasm
phospholipids
molecules that self-assemble into a bilayer to make up the majority of the plasma membrane
glycocalyx
-coating on the outside of the cell membrane
-functions for protection, anchoring, and recognition by the immune system
peripheral membrane proteins
adheres to only one side of the cell membrane
integral membrane proteins
span the whole width of the bilayer
osmotic lysis of a cell could occur in a strongly WHAT solution?
hypotonic
During phagocytosis, a cell reaches out with WHAT to grab onto a
large object and internalize it in a phagosome?
mircofillaments
transmembrane potential
-unequal charge distribution of positive on the outside and negative on the inside across the cell membrane
-ranges from -10 to -100mV
cisternae
membrane sacs of the endoplasmic reticulum
the Golgi functions to modify and sort proteins that are synthesized by the fixed
ribosomes on the WHAT ORGANELLE?
rough endoplasmic reticulum
three types of vesicles are produced at the trans face of the Golgi: secretory
vesicles, membrane renewal vesicles and WHAT?
lyosomes
peroxisomes
membrane sacs that contain oxidases and catalases to neutralize free radicals
proteins tagged with ubiquitin will be sent to the WHAT for recycling?
proteasome
cristae
inner folds of membrane in the mitochondria
aerobic cellular respiration
glucose is catabolized in the mitochondria into water and carbon dioxide in orderto create ATP
nucleolus
dense/dark spot in the nucleus where rRNA
synthesis is occurring
chromatin
loose open form of DNA
nucleosome
formed by DNA wound around histone proteins
in a gene, three bases of DNA make up a WHAT which is the instructions for one amino acid in the protein?
codon
transcription
process of making an RNA copy of a DNA gene
RNA polymerase binds to the WHAT on the template strand of DNA to begin the process of synthesizing RNA?
promoter
AUG
start codon for translation
if an mRNA has the codon CAU, the anticodon of the corresponding tRNA would
be WHAT?
GUA
why does translation stop at the stop codon?
no tRNA with anticodon to stop codon, no new amino acid arrives at ribosomes so the polypeptide chain is terminated
point mutation
-change in one base
-can be a silent mutation if the amino acid is not changed (common at the 3rd base in a codon)
apoptosis
the process of controlled cell death where lysosomes are neutralized
G1 phase
a cell duplicates its cytoplasm during interphase
During the S phase, DNA WHAT unwinds the DNA to allow copying of the information for replication?
helicase
DNA polymerase can add nucleotides only to the WHAT end of a growing DNA molecule
3’
DNA ligase functions to assemble the WHAT fragments into a
continuous lagging strand during DNA replication
okasaki
metaphase
the phase of mitosis where the chromosomes are lined up in the middle of the cell
the two sister chromatids are held together by a WHAT at the kinetochore?
centromere
cancer
caused by abnormal proliferation of cells due to mutations in oncogenes
how many cells does a human have?
~75 trillion cells & ~200 different types
sex cells
sperm and oocyte (eggs)- half of DNA (23)
somatic cells
-every other cell
-all contain full amounts of DNA
-unique morphology is related to function
-all cells surrounded by plasma membrane
cytoplasm
consists of cytosol (fluid) and organelles (structure)
interstitial fluid (outside membrane)
surrounds body cell
plasma/cell membrane
-phospholipids bilayer dynamic
-6 to 10 mm thick
-interface between cell and environment
-selective permeability of membrane allows
different conc. of molecules in/outside cells
-the inside surface is negatively charged due to the abundance of proteins
-outside surface is positively charged due to cations in extracellular fluids
functions of the plasma/cell membrane
-the physical barrier that maintains homeostasis
-regulates exchange with the environment
-provides sensitivity via receptors: cell communication
-provides structural support
phospholipids (membrane)
self assemble into bilayer
cholesterol (membrane)
resist osmotic lysis, stiffens
carbohydrates (membrane)
-linked to other molecules such as proteoglycans, glycoproteins, and glycolipids
-The carb part protrudes from the extracellular side creating outer carb layer called glycocalyx
functions of glycocalyx
-lubrication & protection
-anchoring & locomotion
-binding specificity (receptor bind ligands)
-self recognition by immune system
proteins (membrane)
-1/2 mass of membrane
-contain integral & peripheral proteins
integral proteins
-most common
-span within membrane
peripheral proteins
adhere to inner/outer surface
anchoring proteins
attachment
recognition proteins
self-identification by the immune system (glycoproteins)
enzymes
catalyzer in cytosol or extra cellular fluid
receptors
-binds ligands for signaling or import/export
-ex: ions, nutrient molecules, hormones
carrier proteins
transport solutes in/out
channels
moves ions & H20 in/out
passive tranport
require no energy from the cell, rely on diffusion principles
active transport
requires a transport protein which uses energy from ATP to pump a particular substance against its diffusion gradient
simple diffusion
-net movement of molecules from an area of high concentration to an area of low concentration across a diffusion gradient toward equilibrium
-transport of nonpolar & lipid soluble
rates of simple diffusion
-distance: shorter the distance, faster
-molecule size: smaller the molecule, faster
-temperature: hotter it is, faster
-gradient size: larger difference, faster
-electrical forces: opposite charge, faster
facilitated diffusion
-diffusion through a transporter substances
-rate of diffusion depends on the number of carrier molecules for the specific substance
carriers (facilitated diffusion)
proteins that bind a particular large or polar molecule
channels (facilitated diffusion)
proteins that act as selective pores for water or ions
leak channels
always open