midterm review Flashcards
what are the similarities of the cells
- requires o2 and energy yielding nutrients to sustain life
- removal of c02 and other waste products
- biochemical mechanism to convert nutrietns to energy
- replication: the ability to reporducce new cells from older- cells some exceptiosn
what are the 4 primary tissue types
muscle
nervous
epithelial
ct
what types of cells are in the 4 primary tissues
muscle: for contraction: skeletal cardiac smooth
nervous; for communication; neurons glia
e.t: for forming membranes and glands
membranes: squamous, columnar, cuboidal
glands: exocrine, endocrine
c.t: specialized for providing nutrients structure and support
what is an organ
composed of 2 or more primary tissues (often all 4)
largest organ in body
skin
what is a system
organs that are located in diff regions of the body and that perform related fnctions
examples of systems
integumentary, nervous, endocrine, skeletal, muscular, circulatory immune respiratory urinary, digestive reproductive
idea behind homeostasis
bodys way of maintaining appropriate environmental state to provide optimum function
how does homeostasis apply to physiology
phyisiology is largeyly about maintaining homeostasis in the body
what molecules does the cell membrane pass and not pass without channels
pass: anything without a charge
channel needed: charge
what molecules found primarily in extracellular space
know: cl- na+
and o2
what molecules found primarily in intracellular space
know: K+
and Mg+, phosphate ions (atp, adp, crp,)
what is plasma
circulating blood without erythrocytes
what does the interstitial space resemble
intracellular
how does hemoglobin maintain homeostasis in blood ox
oxygen-buffering function of hemoglobin: hemo carries 02 in blood and regulates o2 concentration in extra fluid.
if o2 is high hb does not release it
if o2 is low, o2 released to reestablish concentration
how does the brain maintain carbon dioxide concentrations from becoming to high
higher then normal co2 excites the respiratory center in bran and causes person tobreakth faster and deeper, this increases amount of co2 returning to the lungs
what cranial nerve are involved with the process of regulating co2
vagus and glossopharyngeal
what is the name of the sense organ/receptor that detects carbond diozide levels
chemoreceptors and carotid body
what brain area acts as the major thermostat fro the body
hypothalamus
wuse a negative feedback loop model to explain how blood glucose levels are maintained
- eat food, stimulus: rising blood glucose level
- high blood glucose level is detected by insulin secreting cells of pancreas
- pancreas secretes insulin causing liver to take up glucose and store it as glycogen and cells take up glucose
- as body cells take up blood glucose, glucose levels in the blood decline and insulin release stops
- return to homeostatic blood glucose level
explain how positive feedback loop works
its like a snowballing effect
how is positive feedback diff then neg feedback
positive causes more stuf too happen
negative causes stuff to stop if too much
pos or neg more common in body
neg
how does oxytocin act in the feedback loop of uterine contractiosn during childbirth
- head of fetus pushes against cervix
- nerve impusles from cervic goes to brain
- brain stimulates pituitary gland to secrete oxytocin
- oxytocin carried in bloodstream to uterus
- oxytocin stimulates uterine contractsion and pushes fetus toward cervix.
- which makes head of fetus pushes against cervics
what are some other examples of positive feedback looops
blood clothing: tissue cut, clotting factors come until a clot is formed
child birth:
nerve signals: na+ leaking into tissue, cause membrane to change and it has to continule until reaches fibers
hemorrhaging: blood not reaturining to heart (vicious cycle)
allostasis
when you reset the normal set point
examples of allostasis
changing salt levels in body cause of high salt diet
stress and cortisol
plasma membrane
amphipathic bilayer made mostly of phospholipids separating intercellular (protoplasm) from extracellular environment
nucleus
membrane bounded organelle that contains genetic material
cytoplasm
jelly like substance that contains the organelles between the cell mrmbane and the nuclea membrane
nuclear envelope
2 phospholipid bilayer (4 lines phospholipid involved) that has pores that allow transfer of substances in and out
the outer layer joins e.r
cytoskeleton
structural part of protoplasm, microtubules and microfilaments, intermediate fibiers
nucleolus
no membrane surrounding it, a mass of ribosomal rna
ions mainly in extracellular fluid
na, cl, ca2+
what types of proteins found in cytoskeleton
microtubules, microfilaments
how are they similar and diff (microtube and microfilm)
tubule : support, main system for protein transport of big things
filament: motility, important for cell moving nad cell division and maintaining general shape
both are shaped similarily but fil is smaller
what types of lipids are found in cell membranes
phospholipids: main part of layer
cholesterol: creates kinks in cell so membrane is more fluid and on schwann cells
what roles do carbs serve in cell
for nutrition, confer special properties to proteins by changing their structure when attached
i.d. tag stuff
name 3 major functions of the cell membrane
- allows selective communication between intracellular and extracellular compartments
- aids cellular movement
- gives cell its form
which part of the cell membrane is hydrophobic
nonpolar tail
which part of cell membrane is hydrophilic
polar head
what is a micelle
a bunch /small group of phospholipids that form a sphere
liposome
ABUNCH lot of phospholipids that form a bilayer and sphere
how are integral and peripheral proteins structurally different
integral: protrudes the bilayer
peripheral: only attached to 1 layer
how are integral and peri proteins functionally diff
integral: provides channels/pores, carrier proteins in active transport, enzymes and receptors
peripheral: attaches to integral proteins, mostly enzymes
glycocalyx
loose cho coating on the outer surface of the cell membrane which has several functions
glycolipid
membrane carb combined with lipid
glycoprotein
membrane carb combined with protein
function of glycocalyx
- makes cell sticky and bind to other cells
- makes it receptors for binding hormones like ligans
- gives surface a negative charge and repel negative molecules
- assist with immune reactions
what is extracellular matrix
fluid outside of cell
basic properties described by the fluid masaic model of the cell membrane
cell is not stuck
there are lots of things in phopholipid
what part of cell involved in making long term changes to diff environmental signals
nucleus
difference b/w genetic vs epigenetic effect on gene expression
genetic: alters directly on dna transcription
epigenetic: changes NOT ON dna but on gene expression
ex: of diff of genetic vs epigenetic
X-chromosome inactivation
histone acetylation/deacetylation
describe how histone acetylation works
dna (neg charge) wrapped around histone protein (pos), prevents dna from being exposed and transcribed
addition of acetyl group unwinds and exposes dna allowing transcription (therefore expression)
chromosome
contains genes cause dna has genes (larger visible chromatin)
chromatid
Each of the two threadlike strands into which a chromosome divides longitudinally during cell division. Each contains a double helix of DNA
chromatin
smaller version of chromosome (dna around histone)
heterochromatin
state of chromatin where dna is tightly around histone so not transcirbable
euchromati
loose chromatin that is ready to be transcribed
why dna naturally wrap around histone protein
because dna is neg histone is positive
nucleolus
has no membrane surrounding it, a mass of ribosomal rna
similar and diff between plasma membrane nad nuclear envelope
plasma membrane surrounds entire cell
nuclear envelope surround nucleus
where in cell find ribosome
nucleolus and cytoplasm and e.r
molecular component of ribosome
1 rna, 1 ribosomal protein (5 carbon sugar)
function of ribosome
protein making factories
how e.r. connected to nucleus
it is a continuation of outer membrane of nuclear envelope
how 2 types of e.r. diff structure
rough er has ribosome
how. 2 types of e.r. diff functionally
smooth: synthesizes lipid substances
rough: synthesizes new proteins in cell
name of process where carb tag is added to synthesized protein in e.r or Golgi ap
glycosylation
how proteins get transported from e.r. to golgi
small e.r vesicles pinch off e.r and fuse with Golgi apparatus
what is characteristic structure of Golgi apparatus
cisternae: stacked layers of thin vesicles
what types of functions do vesicles realsed from Golgi apparatus have
- form lysosoems
- form secretory vesicles
- for other cytoplasmic components
- take proteins and enzymes to outer cell membrane
5 make chondroitin sulfate - make hyaluronic acid
how lysosomes formed
from breaking off of the Golgi aparatus
what is lysosome function
digesting food particesl that have been digested by the cells
destroying bacterial components
digesting damaged cellular components
what type of biochemical process does a lysosome use to digest larger material
autophagy
how are lysosome related to apoptosis
certain enzymes pass through the semi-permeable membrane of lysosome and destroy cell in ordered fashion preventing relase of cell components into extracellular environment
how lysosome related to necrosis
contents of lysosome are emptied and hydrolytic enzymes attack host cell
whats difference of apoptosis and necrosis
necrosis is uncontrolled
how are peroxisomes formed
from self replication of budding off the smooth er (not Golgi)
what are functions of peroxisomes
they contain oxidases rather then hydrolases. the oxidases combine O with H to form hydrogen peroxides which oxidizes poisonous substrances
what kind of molecules are broken down by peroxisomes
detoxify alcohol and break down long chain fatty acids
what biochemical process do perosixomes use
pentose phosphate pathway or glycolysis?
what structural characteristics of mitochondria
has 2 bilayers (like nuclear fold)
major function of mitochondria
atp synthesis by infolding to for shelves for ribosomes and oxidative enzymes
how mitcochondria replicate
mtdna is replicated but some could be replicated more then other
how has mitochondria replication been used in genetic studies
mtDNA is passed on maternally so can trace it back
pinocytosis
lil nibble, cell drinking,
ingestion of minute particles by foring vesicles of extracellular fluid and the particles suspended in it
invagination
receptor mediated endocytosis
molecules bind to protein receptors in coated pits, when pit is full the entire pit invaginates and forms a vesicle
phagocytosis
similar to pinocytosis but for larger particles
major purpose of pino, receptor mediated endo, phago
pino: invaginates and takes stuff from extracellular fluid
receptor: brings in specific molecules cause of the receptor process
endo: to take things out
phago: eats and destroys things
how does a lysosome function with pino, receptor med endo, phago
in all three endocytosis, lysosomes attach to the vesicles nad empty their digestive enzymes into the vesicles
multivesicular body
a lysosome that is a membranous sac containing numerous small endocytic vesicles
what are the molecules that carry heritable information
dna
what are the molecules that carry out the functions of this infor withitn the cell
proteins
how woudld you explain clarify the statemvent “ive got defective gene for dancing so that is is biologically more accurate
you have the gene because you are born with ti, it just isn’t being expressed
it expresses at 2 diff points: during development and when adapting to outside environment
gene: hair color
allele: specific brown haircolor
what is central dogma
dna - rna - protein
what is a nuclesome
dna surrounded by a pile of histones
how is a nucleosome organized
it has the dna strand wrapped around the histone, tight
what is the structure of dna
dna is a double helix with alternating phosphate and deoxyribose molecultes
what are the specific molecules that are found in dna
phosphate, deoxyribose
nitrogen bases: adenine, thymine, guanine, cytosine
how are base pairs organized in dna
a-t
c-g with hydrogen bonds
how does the organization of dna base pairs compare /contrast to mrna
a-u
c-g
mrna does not use t
what structurally defines a gene
idk its expression by transcription factors?
what is attached differentlay to the 5’ end of dDNA rather than the 3’ end
5’: phosphate
3’: oH
what is the name of the enzyme hat unzips dna for both replicaion and transcription
dna helicase
what is a transcription factor
could be an enhancer, repressor, co-activator that affects the expression of genes
qhat is the major enzyme involved in initiating transcription and polymerizing mrna
rna polymerase
in what direction does elongation take place
5’ to 3’
what molecular actors affect the differentiation and specialization of cells in developoment
transcription factors
how do molecular actors affect the differentiation and speicialiation of cells in deveklopment
(helps determine how the zygote divides and differentiates into specialized cell types)
what type of base pair bonding takes place between dna and polymerizing mrna
a-u
c-g
how many mrna molecules can be transcribed from the same dna at the same time
many/?
what factors affect termination of transcription
coding sequence of dna or automatic folding and dissoacitaion of mrna once produced
what are micro rna
mini strands of mrna
what function do micro rna have
that swim their way between mrna strands and ribosomes to prevent translation
how are mrna different than trna
mrna is a specific ribonucleic acid and it codes straight from dna,
trna binds to mrna codons and carry the amino acid end products
where do u find rrna
in ribosome
what are some of the differences betwwn pre mrna and mature mrna
premrna is the nuclear mrna created from transcription, it has introns and exons
mature mrna has only exons in it (translocation)
what does a spliceosome do
cleaves out portions of mRNA that will not be translated to proteins
how can the same strand of dna creat different mrna splice variants
splicing of specific introns and exons allows for different splice variants to be created from the same dna sequence
what is a UTR
Untranslated Region
what functions does a 5’ cap and poly A tail serve
5’cap tells where transcription start
poly a tail: makes it stable so that nucleases eats the small rna pieces
what part of the premRNA (and DNA0 will be spliced out of the mature mrna strand
introns
which part will be remain in from the premrna strands in the now mature mrna
extrons
what part of the cell does most rna splicing take place
nucleus
in what part of the cell does translationtake place
cytoplasm
what is a codon
triplet sequence of nucleotides
what type of molecule will have a codon
mrna
what is an anti-codon
A sequence of three nucleic acid bases on transfer RNA molecules which recognizes and binds to three corresponding bases (called a codon
what type of molecule will have an anitcodon
trna
what is the start codon
ATG
what is the amino acid associated with it
methionine
what are the stop codons
UAA, UAG, UGA or TAA aka
what are the amindo acids associated with it stop
none
why is it that most point mutations in a base result ina funcitional protein without major pathophysiology (there are multiple answers)
because it only affects one gene not the whole chromosome (usually the gene mutation just affects like the neding of a protein or switches amino acids)
also most mutations occur in the gray intron areas so even tho on dna its not trascnribed to protein
where would one expect to find most mutations between individuals in mRNA
in the middle where you do splicing out (the introns)
why would one expect to find most mutations between individusl in mrna
because that is the begning of the transcription and there are lots of places to remove stuff
cause it decides what becomes a protein
what is the directionality of translation of the mrna
5’ to 3’
what molecule provides most of the neryg to creat the new peptide bonds between the amino acids in the newly formed chain
atp
describe a negative feedback mechanism on DNA synthesis
purines and pyrimidines are needed in equal amounts for dna synthesis tooccur
purines inhibit enzymes for purine formation and activates enzymes for pyrimidine (opposite of pyrimidine)
describe a generic model for negative feedback in enzymatic synthesis of products
enzymes help make stuff and as more of that stuff is made,the enzyme is inhibited (allosteric conformational change)
describe the stages of the cell cycle, what occurs during each of thediff maor stages
G1: normal time of cells
checkpoint: start to build up metabolites
S synthesis stage: everything in cells has doubled, dna replicated
G2 growth 2: everything is priming for division, fixing errors in dna replication
M: cell division
how much of the cell’s life cycle is spent in mitosis
5%
how does dna replication work
in the S phase: both strands of DNA is replicated completely and dna is exposed
what enzymes are involved in dna replication
dna polymerase dna ligase (not in rna)
how does dna replication differ from transcription
its different then transcription because it neds the entire strand replicated and nothing is deleted out and there are 2 strands being developed so there are lil gaps while replicated that are put together
would dna ligase act in transcrtion why or why note
no because dna ligase puts the pieces of dna together because of the unwinding of the dna makes it hard to make a solid strand of new dna
what enzymes are involved in dna proofreading
dna ligase and polymerase
what happends when dna proofreading fails
mutation
are the consequences of failed proofreading always dire or mostly negligible
causes abnormal proteins , can lead to cell malfunction or cell death
majo even in prophase
chromosomes are condensed and paired up to form chromatids, centromeres start to line in the poles of the cell
major even in prometaphase
nucleus envelope dissolves, microtubules legs go out to grab chromatids
major event in metaphase
chromatids line up
major event in anaphase
chromatids pulled apart
major event in telophase
cytokinesis, nuclear envelope forms
what is cytokinesis
cells pinch off from each other
how is a totipotnent stem cell different tha a pluripotent stem cell
toitipotent stem cells: have unlimited capability of forming things, ex: embryo
pluripotent: are capable of giving rise to most tissues ex: inner mass cells but not every like toitipotent
how is a totipotent sten cell different then a multipotent stem cell
toitipotent: anything
multipotent: only give rise to cells with a sepcific function like blood stem cells (the most specific stem cell of htem all)
be able to explain how ccervical cancer can be c acused bby hpv. should involve transcription, translation, cell division (proliferation) and apoptosis
the virus is a nucleic acid that uses central dogma to start making proteins
hpv 16 and 18 cause it
virus invades cells genomes and becomes rna and prteins. e5-7 come together and get rid of check points in cell division
usually cell kills itself with apoptosis but virus wont let it with the e5-7 proteins
what are some of the major ions foundi n higher intracellular concentrations relative to the extracellurlar fluid
intra: K+ <—- KNOW mg + phosphate atp, adp, crp
what about higher extracell concetrations (whats more ions in extra)
Na+ Cl- Ca2+ <—KNOW o2
what are some of the charges on these ions (intra and extra)
mainly + except for Cl- (extra)
there are some proteins with - charge intra
charges of other molecules intra and esxtra
proteins - in intracellular
what type of energy source fules the diffeusion of molecules
goes from high concentration to low; DONT need atp
what are the different charges fo the components of the lipid ilayer
polar charged head
nonpolar unchard tail
what molecules are kept from passing thorugh the membrane cause of charged bilayer
polar things
what molecules are free to pass throught eh membrane (charge solubility)
nonpolar thigns fatty things
what are some expamples of lipid soluble molecules
steroid hormones (testosterone, estrogen cortisol)
What is the name of the specialized channels in the cell membrane that allows water to pass through freely?
aquaporins
Why can’t ions pass through these channels
hydration shell (water around ions) make it too big
What must happen for a K+ ion to become small enough to travel through a leaky K+ channel? How does this occur?
they have to strip their hydration shell (by the integral channel) once gets into cytosol, the hydration molecules attach back
Does this require energy from ATP? (K+ shell)
no
What are two common mechanisms for Na+ ions to travel across the membrane through Na+ channels?
ligand gated channels/chemically gated
voltage gated
What is the name of the common ligand-gated Na+ channel found at the neuromuscular junction.
nicotinic receptor (the gate) is ligand gated chanells
How does a voltage-gated Na+ channel contribute to the action potential positive feedback loop?
as more and more charge builds up, it makes the actional potential happen
In facilitated diffusion, is ATP required?
no
In the facilitated diffusion of glucose, insulin signaling to cells promotes what process that inserts carrier proteins into the cell membrane?
membrane trafficking (brings more glut 4 to membrane)
What is the specific name of the carrier protein in the insulin-glucose example above?
Glut 4
What are the 3 factors that affect net diffusion?
- size of concentration gradiatent
- electromotive force/Nernst potential (compare pull of ions)
- pressure difference across the membrane
What is the definition of osmosis?
diffusion of water caused by a concentration difference of water
In a 0.9% NaCl solution, what is the solute, what is the solvent?
solute: nacl
solvent: water
Which solution has greater osmotic pressure, 0.9% NaCl, or 19% NaCl?
19% nacli
What would happen to your red blood cells if you received an IV of distilled water rather 0.9% NaCl? Why?
cells become stuffed with water nad be hypotonic because water wants to go into the cell cause it has less h20 in it and has solute in it
Where are the cells that detect changes in plasma osmolarity? How do they work?
osmoreceptors
when plasma has low water concentration the cells lose water to hyperotinc blood and deform cells which signals osmoreceptors to release adh
the name of the hormone secreted that tells the kidneys to conserve urine? Where is it secreted from?
adh,
posterior pituitary
Does osmosis explain why our fingers become wrinkled after spending a long time in the shower? Why or why not? What other mechanisms might be at work?
m
What is the difference between primary and secondary active transport?
s
How are carrier proteins different in active transport vs. facilitated diffusion?
s
In the Na+/K+/ATPase pump, how many ions of each type, and in what direction, do they go relative to the cell membrane?
d
Is this towards or against the concentration gradients?
d
How does this pump alter osmolarity to regulate cell volume?
d
How does this pump contribute a net division of charge (electromotive force) to the cell membrane?
d
Where do you find the highest concentrations of calcium?
s
How do you bring calcium into the cytoplasm? Describe one mechanism, and include the number of ions and the energy requirements.
d
Contrast symport from antiport transport mechanisms. Give an example of each
s
What type of mechanisms exist for bulk transport? How does each type compare relative to the size of molecule or molecules it can shuttle into or out of the cell?
s
