biology Flashcards
four fundamental tenets of cell theory
A - all living things are made of cells
B - basic fundamental unit of life
C - cells from from pre-existing cells
D - DNA
prokaryotic organisms are always ________, while eukaryotic organisms can be ________
single-celled
unicellular or multicellular
eukaryotic cells contain a _______ while prokaryotic cells do not have this
a true nucleus
in eukaryotic cells, most organells are _________
membrane bound
the membranes of eukaryotic cells consist of what
phospholipid bilayer
eukaryotic cells reproduce by _______
mitosis
linear DNA is wound around organizing proteins known as __ and is further wound into linear strands called ____
histones
chromosomes
rRNA is synthesized where
nucleolus
the inner membrane of mitochondria are arranged into infoldings called
cristae
cristae contain the molecs and enzymes of the ______, and also help to increase the ____ available for this as well
electron transport chain
surface area
mitochondria replicate independetnly how
binary fission
cytoplasmic or extranuclear inheritance is what
the transmission of genetic material independent of the nucleus
mitochondria are thought to have originated when
when the engulfing of an aerobic prokaryote by an anaerobic prokaryote resulted in a symbiotic relationship
mitochondria are also capable of killing the cell how
release of enzymes from electron transport chain - apoptosis
lysosomes are what
membrane bound structures containing hydrolytic enzymes that are capable of breaking down substrates
they function in conjunction with endosomes
endosomes do what
transport, package and sort cell material
the er is what
a series of interconnected membranes that are actually contiguous with the nuclear envelope
the rough er is studded with ___ which permit the translation of _____ destined for secretion directly into its ___
ribosomes
proteins
lumen
smooth er lacks ribosomes and is utilized primarily for _______ and the __ of certain drugs and poisons
lipid synthesis
detoxificationthe golgi
apparatus consists of _______
stacked membrane bound sacs
when inside the golgi apparatus, cellular products may be modified by the addition of groups like what
carbs
phosphates
sulfates
the golgi apparatus can also modify ceullular products through the introduction of what
SIGNAL SEQUENCES
cells that require a lot of energy or locomotion like sperm cells will have a lot of what
mitochondria
cells that are involved in secretion like pancreatic islet cells have high conc of what
RER
peroxisomes contain what
hydrogen peroxide
one of the primary functions of peroxisomes is the ___________. they also participate in the synthesis of ___ and contain some of the enzymes involved in the ____ pathway
breakdown of long chain fatty acids via beta-oxidation
phospholipids
pentose phosphate pathway
three components of cytoskeleton
microfilaments
microtubules
intermediate filaments
microfilaments are made of solid polymerized rods of _____
actin
actin filaments can also use ATP to generate force for movement by interacting with ___
myosin
microfilaments also play a role in __, by forming the _______ in mitosis, by oranizing into a ring at the site of division between two new daughter cells
cytokinesis
cleavage furrow
microtubules are hollow polymers of _ proteins
tubulin
microtubules provide the primary pathways along which motor proteins liek ____ and ___ carry vesicles
kinesin
dynein
cilia are __
projections from a cell that are primarily involved in the movement of materials alon ght esurface of the cell
flagella are
structures involved in mvmt of cell itself
9 + 2 structure
nine pairs of microtubules which form an outer ring, with two microtubules in the centre - structure of cilia and flagella
centrioles are found where and what are they
centrosome
organizing centers for microtubules and are structured as nine triplets of microtubules with a hollow centre
intermediate filaments include what
keratin, desmin, vimentin, lamins
intermediate filaments are involved in what
cell cell adhesion or maintenance of overall integrity of cytoskeleton
four tissue types
epithelial
connective
muscle
nervous
epithelial tissues cover the body and line its cavities, and in certain organs, are involved in ___________. they are tightly joined to each other and to an underlying layer of connective tissue known as the ___
absorption
secretion
sensation
basement membrane
in most organs, epithelial cells constitute the _______ - functional parts of organs
parenchyma
epithelial cells are often ______
polarized
simple epithelia
stratified
psuedostratified
cuboidal
columnar
squamous
one layer of cells
multiple layers
appear to have multiple layers - due to diffrences in height but are only one layer
cube
long and thing
flat and scalelike
whereas epithelial tissue contribute to the parenchyma of an organ, connnective tissues are the main contributos to the __ or support structure
stroma
in prokaryotes, dna is concentrated in an area of the cell called what
nucleoid region
three overarching domains into which all life is classified
archaea
bacteria
eukarya
which of the domains contain prokaryotes?
archaea and bacteria
historically, archaea were considered what
extremophiles
archaea contain a single circular ________, and divide by ______ or ________
chromosome
binary dission
budding
many antiobiotics target the bacterial ______, which is ______ than the eukaryotic one
ribosome
smaller
examples of mutualistic symbiotes
bacteria in human gut that produces vitamin K and biotin (B7) also help prevent growth of harmful bacteria
bacteria shape 3
cocci - spherical
bacilli - rod-shaped
spirilli - spiral shaped
the type of cell wall is determined by what
gram staining process
crystal violet stain, followed by counterstain with substance called safranin
if envelope absorbs crystal violet stain, it will be _ and is gram ___
deep purple
positive
if the envelop does not absorb the crystal violet stain, it will be __ and is gram _____
pink-red (absrosb safranin counterstain)
negative
gram positive cell walls consist of a thick layer of _____, a polymeric substance made from _____ and ______. in addition, the cell wall may also aid a bacterial pathogen by ________. it also contains ___ acid.
petidoglycan
amino acids
sugars
providing protection from host organism’s immune system
lipoteichoic
gram negative cell walls are very _ and also contain ____ in smaller amounts. these walls are separated from the membrane by the __ space. in addition to this, gram negative bacteria also have ______ containing ____ and _____. ___ are the part of gram negative bacteria that triggers an immune response in human beings
thin
petidoglycan
periplasmic
outer membranes
phospholipids
lipopolysaccharides
lipopolysaccharides
the inflammatory response to ___ is much stronger than the response to ___
lipopolysaccharides
lipoteichoic
the ability of a cellto detect chemical stimuli and move toward or away from them is called
chemotaxis
the hook in flagella do what
connects the filament and the basal body so that as the basal body rotates, it exerts torque on the filament which thereby spins and propels the bacterium forward
plasmids carry what
DNa that is not necessary for survival of the prokaryote
binary fission process
circular chromosome attaches to cell wall and replicates whi the cell continues to grow in size
eventually plasma membrane and ell wall begin to grow inward along midline of cell to produce two identical duaghter cells
in addition to genes that impart some benefit to bacterium, plasmids also carry
additional virulence factors = traits that increase pathogenicity - e.g. toxin production, projections that allow attachment to certain kinds of cells, or features that allow evasion of host’s immune system
subset of plasmids is called ________ they are capable of integrating into the genome of the bacterium
episomes
3 forms of genetic recombination
transformation
conjugation
transduction
transformation describe
results from integration of foreign genetic material into host genome - foregin genetic material most frequently comes from other bacteria that spill their contents into civinity of bacterium
many gram negative rods are able to carry out this process
conjugation describe
bacterial form of mating
two cells form a conjugation bridge, facilitates transfer of genetic material
transfer is unidirectional from donor male (+), to recipient female (-)
bridge is made from appendages called sex pili found on donor male
the best studies sex factor in bacteria is what in what
fertility factor in e.coli
bacteria that have this are called f+ cells
transduction describe
only genetic recombination process that requires a vector
bacteriophages can accidentally inforporate a segment of host DNA during assembly - when bacteriophage infects another bacterium, it can release this trapped DNA into new host cell
transposons
genetic elements capable of inserting and removing themselves tfrom genome - has been seen in both pro and eu karyotes
if transposon is inserted within coding region of gene, gene might be disrupted
lag phase
bacteria first adapting to new local conditions
exponential phase/log phase
rate of divison increases
stationary phase
reduction of resources slows reporduction
the protein coat in viruses is known as what
capsid
enveloped viruses are easier to kill t or f
t
viruses must express and replicate genetic info within a host cell bc they lack
ribosomes to carry out protein synthesis
tail sheath in bacteriophages can act like what and then what help the bacteriophage recognize and connect to correct host cell?
syringe - injects genetic material into bacterium
tail fibres
postive sense is what
implies genome may be directly translated to functional proteins by the ribosomes of the host cells - just like mRNA
negative sense RNA viruses are what
complicated - negative sense RNA strand acts as a template for synthesis of a complementary strand, which can then be used as a template for protein synthesis
negative sense RNA viruses must carry an _________ in the virion to ensure that the complementary strand is syntheiszed
rna replicase
retroviruses are what
enveloped, single stranded rna viruses
virion contains two identical rna molecules - carry an enzyme known as reverse transcriptase - synthesizes DNA from single stranded RNA
HIV utilizies what kind of life cycle?
retrovirs
most DNA viruses must enter the _ in order to be transcribed into ___
nucleus
mRNA
genetic material from poitive=sense rna viruses stay in the __, where it is directly translated into __ by the ________. negative sense RAN viruses require syntehsis of a _______ via rna replicase, which can then be translated to form ____
cytoplasm
proteins
host cell ribosomes
complementary RNA strand
proteins
viral progeny can be released how 3
initiate cell death, spilling of viral progeny
host cell may lyse
can leave cell by fusing with plasma membrane - extrusion
lytic cycle
bacteriophage maximizes use of cell’s machinery with little regard for survival of host cell - viruses termed virulent
lysogenic cycle
virus replicated as bacterium reproduces because now part of host’s genome
prions
infectious proteins and non libing things
triggers misfolding of other proteins through conversion of protein from alpha helical structure to beta pleated sheet
reduces solubility of protein, as well as ability of cell to degrade protein
protein aggregates form eventually, interfering with cell fuctnion
cause mad cow disease, familiaal fatal insomnia
viroids
small pathogens consisting of very short circular single stranded RNA that infect plants
bind to large number of RNA sequences and can silence genes in plant genome
prevents synthesis of necessary proteins - metabolic and strucutral damage to cell
widest part of fallopian tube
ampulla
what does the sperm form when in contact with secondary oocytes cell membrane?
tube like structure
acrosomal apparatus
cortical rxn
release of calcium ions
indeterminate cleavage vs determinate cleavage
- results in cells that can still develop into complete organisms
- cells with fates that are already determined
chorion
extraembryonic membrane that develops into placenta
allantois
extraembryonic membrane involved in early fluid exchange between embryo and tolk sac
archenteron
membrane invagination into blastocoel
opening of archenteron
blastopore
deuterostomes, the blastopore develops into what and in protostomes what
anus
mouth
ectoderm rise to
integument, epidermis, hair naisl epithelia of nose mouth lower anal canal lens of eye ns inner eare
mesoderm rise
musuloskeletal circulatory excretoryd
endoderm
internal organs
adrenal cortex is derived from the ___ but the adrenal medulla is derived from the ____
mesoderm
ectoderm (bc it contains some nervous tissue)
autocrine signals
act on same cell that secreted signal in first place
paracrine signals
act on cells in local area
juxtacrine signals
dont usually involve diffusion but involve a cell directly stimulating receptors of an adjacent cell
endocrine signals
involve secreted horomes
reciprocal development
differentiation of the lens then triggers optic vesicle to form the optic cup - ecomes retina
axons carry neural signals ____ from soma, and dendrites carry signals _____ soma
away
toward
axon hillock
integrates incoming signals - plays importnat role in action potentials
oligodendrocytes and schwann in which system?
cns and pns respectively
astrocytes
nourish neurons - form bbb
ependymal cells
line ventricles of brain and produce cbf
microglia
phagocytic cells inest and break down waste products and pathogens in cnsoligodendro
cytes + schwann
produce myelin around axons
neurons resting potential
-70mV - inside is neg relative to outside
K+ conc inside cell avg
140mM
4mM outside cell
potassium equilibrium potential
-90mV
equilibrium potential for sodium
60mV
temporal summation
multiple signals are integrated during relatively short period of timespa
spatial summation
additive effects are based on number and location of incoming signals
sodium channels being
closed
open
inactive
before cell reaches threshol and after inactivation has been reversed
from threshold to approx +35mV
from approx +35mV to resting potential
difference between electrical and chemical transmission
withint a neuron, electricity is used to pass signals own the length of the axon
between neurons, chemicals are used to pass signals to subsequent neuron
peptide hormones
amino acids - all derived from larger precursor polypeptides that are cleaved during posttranslational modification
peptide hormones have ____ receptors and act via ____
surface
second messenger systems
steroid hormones bind to ______ receptors and function by binding to ____ to alter gene transcription
intracellular
DNA
where are steroid hormones derived from?
cholessterol
nonpolar molecules - can easily cross cell membrane
the effects of ____ hormones are slower byt longer lived than ___ hormones bc they particilate in ____ causing alternations in amount of mRNA and protein present in a cell by direct action on DNA
steroid
peptide
gene regulation
in the heart, impulse initiation occurs where
at the SA node
all blood vessels are lined with _____ cells
endothelial
the classical pathway requires what whereas the alternative pathway doesn’t
binding of an antiboyd to a pathogen
MHC-1 pathway is called what
endogenous pathway
MHC 1 is all nucleated cells andpresente endogenous antiens
exogenous pathway
MHC-II
antien presenting cells and presents exogenous antigens
bladder has muscular lining known as what
detrusor muscle
internal and external uretrhal sphincter muscles
internal = smooth contracted in onroamls state
external - skeletal muscle - under voluntary control
micturition reflex
when bladder is full, stretch receptors convey to ns that bladder requires emptying - parasympatheti neurons to fire, and detrusor muscle contracts - also causes internal sphincter to relax
hypodermis
layer of connective tissue that connext skin to the rest of bod
arrector pili
muscles contract causing hairs of kin to stand up on end piloerection
define
filration
secretion
reabsorption
mvmt of solutes from blood to filtrate at bowmans capsule
mvmt of solutes from blood to filtrate anywhere bsides bowmans capsule
movement of solutes from filtrate to blood
countercurrent multiplier system
flow of filtrate through loop of henle is opposite direction from flow of blood through vasa recta
ascending and descending loops of henle permeable to what
a = salts and impermeable to water
d = maximizes water reabsorption
both smooth and cardaic muscle exhibit what activity
myogenic - respond to ns input but do not require exteranl signals to undergo contrction
axial skeleton
skull vertebral column ribcage and hyoid bone
appendicular skeleton
bones of the limbs pectoral girdle and pelvis
tendons and ligaments
muscle to bone
bones together at joints
longitudinal channels - axis parallel to bone
haversian canaels
transverse channels (axis perpendicular to bone_
volkmann’s canals
contain blood vessles nerve fibres and lymph vesses that maintain helath of bone
hardening of cartilage to bone
endochondral ossification
most long bones are formed like this
intramembranous ossification
undifferentaiated embryonic connective tissue is transformed into and replaced by bone
occurs in bones of skull
adductor
moves part of the body toward midline
abductor
moves part of body away from midline
penetrance
population measure defined as population of individuals in population carrying allele who actually express the phenotype
expressivity
different manifesataions of same genotype across population
mendels first and seconf law
segregation
independent assortment
divergent parallel and convergent evolution
independene developemtn of dissimilar charactersitcs in two or more lineages sharing a common ancestor
process whereby related species evolve in similar ways for long period of time in respnse to analogous enviornmental selection pressures
independent development of similar characteristics in two or more lineages not sharing a recent common ancestor
