Quiz 1 Flashcards
5 functions of Plasma Membrane
- Signaling 2.Transport 3.Growth 4.Motility 5. divide cells into compartments
How thick is the plasma membrane
8 to 9 nm
What is the most abundant phospholipid?
Phosphatidylcholine
5 most common phospholipids
1.sphingomyelin 2.phosphatidylserine 3.phosphatidylinositol 4.phasphatidyl-ethanolamine 5.glycolipids
Structure of glycerol
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phospholipid structure
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True or false phospholipids are distributed symmetrically
false
What class of enzymes maintains asymmetry of plasma membrane
Filpases
Glycolipids are made in which organelle
Golgi
Inside of golgi looks like which surface of cell membrane
outer
Phospholipids in membrane are usually turned over how frequently?
matter of hours
5 functions of transmembrane proteins
- transporters
- Receptors
- Anchors
- Enzymes
- Structural
3 ways porteins/channels can gin access to inside of the cell
- Diffusion
- carrier proteins
- Channel Proteins
What is spectrin?
A protein that is important in forming the RBC’s unusual shape.
Proteins with longer carbohydrate chains are called _____
Proteins with shorter chains are called _____
proteoglycans
glycoproteins
What is lectin
Molecule that recognizes and binds to carbohydrates attached to the memebrane of some WBCs
Which phospholipid commonly interacts with proteisn to form lipid rafts?
spingolipids
What is GPI and why is it important?
Glycosylphosphatidylinositol (GPI) important for stability
3 Ways material can enter the cell
- diffusion
- Integral Membrane Protein
- Endocytosis
2 types of endocytosis
- Pinocytosis
- Phagocytosis
What is size of particles ingested with pinocytosis
<150nm
2 types of Pinocytosis
- Clathrin independent
- Receptor mediated Endocytosis
True or false clathrin-independent pinocytosis is a constitutive process
true
What is the main protein we discussed that is involved in clathrin-independent pinocytosis
Caveolin
What is the protein that cuts off a pinocytotic vessel from the plasma membrane
dynamin
What source of energy does dynamin use to cut off vesicle from plasma membrane?
GTP
What is the main protein associated with receptor mediated endocytosis?
Clathrin
What is adaptin/aP-2
binds clathirin to receptor
What word is used to desribe the shape of Clathrin
triskelion
What is Rab-5
labels vesicle for transit through the endosomal pathway
Is dynamin used with clathrin coated vesicles as well?
yes
4 types of ligands that eter the cell via receptor-mediated endocytosis
- Hormones
- Growth factors
- Lymphokines
- Nutrients
What distinguishes early endosomes?
lack of acid hydrolases
T/F all endosomes have a H+ ion pumps
T
- pH of early endosome
- pH of late endosome
- pH of lysosome
- ~6
- 5.5-6
- ~5
What are ESCRT proteins?
Endosomal sorting complex required for transport…label proteins for passage through endocytotic pathway
Where are endosomes synthesized?
Where are endosomes packaged and coated?
- ER
- Golgi
What two things determine [H+]
- number of H+ pumps
- Volume of vescile they have to cover
What does mannose-6-phosphate do
tags hydrolases to transport to endosomes and lysosomes
Why do lysosomes need highly glycosylated coating?
To protect their membranes from destruction
What are rubbery bumps of fatty deposits called?
xanthomas
Is Familial Hypercholesterolemia dominant or recessive?
Dominant
What is affected/ wrong in patients with Familial Hypercholesterolemia?
There is an absense or malfuction of LDL receptors, so recpetor can’t bind to AP-2, so LDL is not endocytosed.
Which ethnic group has particularly high prevanelce of Familial Hypercholesterolemia
French Canadian
True of false, Phagocytosis is always triggered by activated receptors
true
What size particles are ingested via phagocytosis
>250
Which two cell tpes are “professional phagocytes”
- Macrophage
- Neutrophils
In phagocytosis, how does formation of psedopodia occur?
reorganization of actin cytoskeleton
What is it called when a bacterium/particle is coated by antibody or complement?
opsonization
What is complement?
protein constituent of blood that is involved in immune reactions
Which organelle’s membrane is used for autophagy?
ER
How is it possible to distinguish between a phagosome and an autophagosome
autophagosome has two laters of membrane since the membrane comes from the ER
What are vesicles called that have byproducts in lysosomes that can’t be recycled and that aren’t excreted ?
lipofuscin
2 othe rnames for lipofuscin
- wear and tear pigment
- residual bodies
Organelles satisfy which two needs for eukaryotic development
- Increased membrane surface area
- Specialization to attain complexity
4 Benefits of organelles
- Surface area for membrane dependent functions
- Compartmentalization
- Directed flow of proteins
- Degradation
Two categories of organelles
- Membranous
- Macromolecular complexes
What occurs in ER
protein and lipid synthesis and important storage depot for Ca2+
What happens in Golgi?
Proteins from ER are modified and sorted to their specific final locations
In cell fractionation of hepatocyte, what percentage of volume is in cytosol.
What percentage is in membrane bound organelles.
Which organelle took up the most %
What was percentage of nucleus
50
50
Mito
6
In hepatocyte membrane study…What percentage of the membrane did hte plasma membrane account for? What about ER and mito?
2
50
40
What is size range of mitochondria
.5-1 micrometer diameter
T/F mito involved in procceses besides aerobic respiration
T
ex urea cycle
Mitochondira are associated with which cytoskeleton element
microtubues
Mito has how many membranes
how many compartments
2
2
In inner membrane of mito the ratio of protein to lipids is
3:1
Production of ATP occurs where in mito?
matrix side of inner membrane
The business end of the mito is where?
inner membrane
How much more energy from oxidation of pyruvate then from glycolyis
15x
How many protons need to be pumped to make 1 atp
3
How much ATP per second from each ATP synthase?
100 ATP
What are two things that are increased in regards to mitochondra and increased energy demand
- number of mitochondria
- Increased cristae
What makes mitochodrial replication complex?
having two-mebranes and two compartments
What is different about mtDNA
no histones
Most known mtDNA mutations affect hwat?
electron transport/ ATP synthesis
MERRF
Myocolonic Epilepsy with Ragged Red Ribers
affects a gene that does what?
encodes tRNA -lysine
majority of RNA is what kind of RNA?
rRNA
Ribosomes translate which kind of RNA to protein?
mRNA
During translation mRNA moves in what order through the different sites in the ribosome?
A, P, E
____ subunit of ribosomes some as frame where tRNA anticodon reads mRNA codo, ____ subunit catalyzes peptide bond formation
small
large
DNA is translated in which direction
5-3
during replication, which subunit of hte ribosome moves first
large
Ribosome has how many binding sites and what are they named
4
- for mRNA
- A site (aminoacyl)
- P-Site Peptidyl
- E-Site Exit
Any peptide that will be in a membrane-enclosed structure msut enter the
ER
What guides protein to ER
SRP signal recognition particle
Any peoptide that will be inserted into the membrane with in the cell will enter the
ER
Erythomycin blocks which channel
exit
tetracyclines block which site
A site
Chloramphenicol blocks what?
Peptidyl transferase rxn
are proteasomes abundant?
yes
Where are proteosomes located –2 places
cytosol and nucleus
how do proteasomes recognize which proteins have to be degraded?
ubiquination
4 functions of sER
- synthesis of membrane lipids
- synthesis of steroid hormones
- Durg detox
- sequestration of calcium
Cis face of Golgi is closest to what
ER
What kind of modifications are done in Golgi?
glyco modifications of proteins
enzymes for protiens are produced where?
ER and then sent to Golgi for packaging
what is a secondary lysosome/ heterolysosome?
lysosome in which ingested material is degraded
Which enzyme is deficinet in Tay-Sachs
hexosaminidase
What accumulates and wherein Tay-Sachs
Glycolipids in lysosomes of neurons
Is Tay-Sachs
autosomal recessive/dominant
recessive
What happens in Hurler Syndrome
One of the enzymes that breaks down GAGs is affected
Besides tay sachs and hurlers, what other type lysosomal disorder?
around 10 glycogen storage disease
Besides endocytosis what else uses clathrin
vesicle formation from golgi
secretory vesicles have what fold concentration
200-400
size of peroxisome?
0.5 micrometer
Where are peroxisomes most abundant
liver
kidneys
Function of peroxisome–3
- Beta ox of fatty acids
- detox of alcohol and drugs
- synthesis in plasmalogens which make myelin sheaths
2 main rxns of Peroxisome?
- Oxidation
- Peroxidation
IN peroxisomes what two things can happen to hydrogen peroxide
- reduced to Water
- Reduces fatty acid
What happens in Zellweger Syndrome? Most likely what kind of issue
- Absense of peroxisomal enzymes
- probably packaging issues…enzymes are made, but aren’t packaged correctly
What happens in Adrenoleukodystrophy
failure of B-ox of fatty acids
Lipids accululate in nervous system and adrenal glands
Surface area generates what 3 things.
- Complexity
- Differentation
- Longevity
which type of heterochromatin will probably never be unwound? and where is it located
What type of heterchromatin will sometimes be transcribed and where does it go
Constitutive
Stays close to nuclear lamina around the perimeter of the nuclear envelope.
Facultative
More towards the center of the nucleus
how big is the perinuclear space
20-50 nm
How many pairs of chromosomes do humans have
23
How many base paris are wound around 1 pair of histones?
~150
solenoid is how many nm
30
nucleosome is how many nm
11
DNA/ Nucleosome / Solenoid interaction with which portein forms 300 and 700 nm loops
condensins
Which protein complex is capable of moving histones in the nucleosome and also of decondensing solenoids to increase avaiilability of a starand of DNA for transcription?
-Does this require energy?
- Nucleosome remodeling complex
- yes
What are steps for getting something into the nucleus
4 steps
1) Proteins need NLS
2) Proteins with NLS bind to importin
3) Importins bind to nucleoporins
4) GTP is hydrolyzed and protein is released
Which side of nucleus has high [GTP]
nuclear side
Where is tRNA synthesized
The nucleolus
Where does DNA for rRNA come fro?
DNA from 5 pairs of chromosomes
Average size of eukaryotic cell
Aversize of nucleus
10-50micrometers
5–10 micrometers
Is rDNA being transcribed in Fibrillar Center
Is rDNA being transcribed in dense Fibrillar Zone
What’s happening in Granular Zone
no
yes
ribosomal packaging and processing
What are the two subunits of Ribosomes
60s and 70 s
What 3 phases are included in interphase
G1, s, G2
How long is prophase `
+/- an hour
How long is Metaphase
<1 hour
How long is anaphase
<1/2 hour
how long is telophase
minutes
How long is S phase
8 hours
how long is g1
25
about how long is total cell cycle
38 hours
What is division of hte nucleus called
karyokinesis
___ ____ in centrosome are the nucleation sites for MTs
y-tubulin rings
When does nucleolus disappear
prophase
how does nuclear envoelop break down?
lamin phosphorylated by M-CDK
What is the protein called that binds sister chromatids together?
cohesin
around how many proteins make up the kinetochore?
over 60
astral kinetochores are pulled by which motor protein
dynein
polar MTs are pushed by which motor protein
kinesins
What are the steps in the break down of cohesin
- Anaphase Promoting complex (APC) is phosphorylated
- Securin is ubiquinated and destroyed
- proteolytic enzyme (separase) is no longer inhibited by securin and it goes and breaks cohesin
What phosphorylates the APC
CDK
What happens in Anaphase A
Chromes are pulled poleward
What happens in Anaphase B?
Poles are pushed apart
S-Cdk promotes which phase and is present when?
M-Cdk promotes which phase and is present when?
S phase
Middle of G1, to Middle of M
Mitosis
Beginning of G2 to middle of M
How many checkpoints are there
Where are they
What do they check
3.
1) G1 Checkpoint Before S phase
Checks to see if environment is favorable and if there is any DNA damage
2) G2 Checkpoint Before Mitosis
Checks to see if all of the DNA is replicated and if damaged DNA has been repaired
3) Mitosis Checkpoint
Checks to see if all chromosomes are properly attached to spindle
How does Rb protein work?
when active it inactivates transcription regulators, An activated G1/S Cdk phosphorylates it and Rb becomes inactive and the transcription regulator becomes active
What are the two types of kinsases that activate p53
1) activated during cell stress
2) activated when there’s DNA damage.
How does p53 work
p53 is phosphorylated by cdk
active p53 causes production of a protein that inhibits the cyclin/Cdk complex that promotes the S phase
If dna doesn’t get repaired p53 activates mechanisms for apoptosis
Is there an inflammatory response with apoptosis
no
What is one of the most powerful activators of cell suicide
release of cytochrome C from damaged mitochodria
What does Bc1 2 do?
blocks apoptosis
was does caspase do?
trigger cell death
4 types of tissues
epithelium, connective tissue, muscle, nerve
5 functions of connective tissue
- Protection
- absorption
- secretion
- sensory perception
- contractility
What kind of stains do you have to use to see basal bodies
eosinophilic
What is PKD
polycystic kidney disease
inherited defects in the assembly of cilia
What is Bardet-Biedl?
Genes that produce proteins necessary for intraflagellar transport and the formation of cilia
Which type of cellular connector (zona occluda, adherens, and desmosome) has cadherins
zona adheres/ adherent junction and desmosomes
Waht kind of stain do you have to use to see Basement Membrane/ Basal Surface
PAS
what kind of epithelial cells are in respiratory airways
pseudostratifed columnar
GI tract is usually what kind of epithelia
simple columnar
- In cigarette smokers what happes to epithelium
- acid reflux
- pseudostratified to stratified squamous
- stratified squamous to columnar
Type 1 Collagen is found where?
Dermis, tendons, ECM, ligaments,bone
Type 2 Collagen fibers are found where?
Cartilage–fibro, hyaline, and elastic
Type 3 Collagen fibers are found where?
Reticular Fibers–organ stroma
Type 4 Collagen fibers are found where?
basement membranes
What is different about type 4 collagen
no fibers
Steps in collagen synthesis
- pro alpha chain is produced
- post translational modification select lysines and prolines are hydroxylated/ hydrolysines are glycosylated
- 3 pro alpha chains self assemble
- secreted outside of cell
- propeptides cleaved–tropocollagen
- Assemble into fibrils
Which co-factor is needed for collagen to synthesize correctly?
vitamin c
What kind of staining is needed to see type 3 collagen
silver
What two type of fibers make up elastic fibers
Elastin and Fibrillin
Marfan’s syndrome is a deficiency in
Fibrillin
What are two common examples of structural glycoproteins
Laminin
Fibronectin
T/F Fibrillin and Elastin don’t require special staining
false
GAGs are made up of ___ ____ which are then covalently bonded to ___ ___ with the exception of ________ (specific GAG)
disaccharide chains
core protein/proteoglycan
hyaluronic acid (hyaluronan)
Mucous CT is only present during
the embryonic and fetal periods and i the umbilical cord
Macrophage in the liver are called
Kupffer cells
Macrophages in the skin are called
Langerhans
Macrophages in the bones are called
osteoclasts
macrophages differentiate from
monocytes
Mast cells bind what type of antibody
IgE
2 divisions of connective tissues
- Cells and 2. ECM