Exam 1 Flashcards
Levels of hierarchical organization
chemicals, cells, tissues, organs, organ systems, organism
Epithelial tissue function
secretes, absorbs, protects
Connective tissue function
holds it together
Muscle tissue function
contracts & moves
Nervous tissue function
communication & control
What animals do not make vitamin C
primates & guinea pigs; mutations in the gene encoding the last step in the pathway
Vitamin C is used for what
collagen synthesis by fibroblasts
Scurvy affects connective tissue, which means clinical signs are noted where
skin, mucous membranes, & blood vessels
Cholesterol is important for what
membranes & a precursor to steroid hormones & bile acids
Cells acquire cholesterol by what
endocytosis of circulating LDLs
Cholesterol is water insoluble & needs to be transported out the lysosome by
protein machines (NPCs)
With a NPC mutation, what happens to cholesterol
its unable to be removed from the lysosome
Neurological effects from NPC disease due to the toxic accumulation of cholesterol
clumsiness, learning disabilities, & loss of body control (ataxia); premature death
Parasites avoid the spleen by sticking to what
vascular endothelium
Effects of malaria on the body
microvasculature blockage, endothelial activation, organ failure, & cerebral malaria
Medical genetics definition
study of genetic info based on inherited disease
Commodity species are selected for what
production traits
Companion species are selected for what
health & performance
Define genomics
field of studying function & nature of whole genomes/ associated sequence databases
Polymorphism definition
change in DNA sequence relative to a consensus sequence for a species or population
Is polymorphism synonymous to mutation
yes, but mutation implies some lost or changed function
Nature of polymorphisms
single nucleotide changes; large deletions or insertions; other complex changes
Causes of polymorphisms
DNA repair failure; chemical mutagenesis; ionizing radiation; transposable & retro-transposable elements
Different consequences of polymorphisms
none; gain of function; loss of function; attenuated function
Describe gain of function
mutations that changes gene function in a pathological way
Describe loss of function
null defects; usually an absent or totally non-functional protein; critical “site sensitive” mutations (ex: AAs in an enzyme active site; obliteration of a critical signaling sequence)
Describe attenuated function
may confer a trait; may be associated w/ significant disease that is attenuated compared to the more severe (null) form; intermediate function
Coefficient inbreeding equal to 0 means
no in-breeding
Coefficient inbreeding equal to 1 means
completely in-bred (like mice in a lab)
Founder effect definition
rate of disease increases in a new population just by chance
Popular sire & dam effect
same dogs being bred may cause genetic defects in breeds
Most common genetic issues seen in vet med
involves recessive genes since dominant mutations would not be incorporated into breeding programs
Complex inheritance of genes includes what
polygenic; multifactorial; epigenetic; combined effects
Multifactorial includes
environmental & genetic interaction
Epigenetic definitions
non-sequence associated inheritance
Examples of epigenetic
DNA methylation that activates/ inactivates gene expression
Levels of defects (mutations)
developmental; subcellular; direct cell/ cell interactions; soluble ligand defects
Type of developmental defect
cell migration
Subcellular defect
organellar; cytoskeleton; signaling defect; plasma membrane associated defects (receptors; cytoskeleton/ extracellular matrix interface)
Chromatin is what
DNA + histones
Packing & level of expression of heterochromatin vs euchromatin
Heterochromatin is more tightly packed & less actively expressed
What passes through nuclear pores
Small molecules-> diffuse freely
Large macromolecules-> transport regulated
What is the nuclear lamina
nuclear cytoskeleton (scaffolding)
What species have nuclei in RBCs
birds, reptiles, & fish
Nucleated RBCs in mammals can be a sign of what
infection
Nucleolus are one or more dense compartments w/in the nucleus that are the site of
ribosomal RNA transciption & assembly of ribosomal proteins
Describe cause of primary lens luxation
splicing mutation causes early termination during translation; protein important for maintenance of fibers is not correctly made; breakdown of fibers that holds lens in place
Point mutation in what gene causes primary lens luxation in dogs
ADAMTS17; dysfunctional protease results
Proteases play important roles in what
development & maintenance of extraceullar matrix
Dysfunctional protease ADAMTS17 results in what
failure to maintain fibers that hold the lens in place
Ribosomes are called what
translation machines
Synonymous mutation results in
same AA being added
Non-synonymous mutation results in
incorrect AA being added
Single base-pair deletion results in
frameshift mutation- catastrophic
Lens luxation genetic background
autosomal recessive; does not appear until 3 years of age
Primary lens luxation frameshift mutation occurs how
G to A mutation in intron of ADAMTS17 gene causes a splcing error that results in skipping exon 10
Subunit for prokaryotic ribosome
70S = 50S + 30S
Subunit for eukaryotic ribosome
80S = 60S + 40S
Many antibiotics are used to inhibit protein synthesis b/c
prokaryotic ribosomes are sensitive & eukaryotic ribosome are insensitive
Components of the small subunit
protein; 16S rRNA
Components of the large subunit
protein; 23S rRNA; 5S rRNA
Ribosome is mostly made up of
RNA
Where are ribosomes assembled
nucleolus
Where are ribosomal proteins made
cytoplasm
How are ribosomes transported out of the nucleus
via nuclear pores
Where are ribosomes assembled w/ rRNA
in nucleolus, then exported to cytoplasm
What occurs if the assembly of ribosomes is interrupted
nucleolar stress-> cell death
Ribosomal protein haploinsufficiency occurs when
mutation in one allele of a ribosomal protein leading to half as much of that subunit
Depletion of one subunit causes what
excess in other subunits
When the assembly of ribosomes is disrupted & nucleolar stress occurs, what does this mean
proteins leak out
Excess ribosomal subunits activate what
p53 signaling
p53 is responsible for what
cell cycle arrest and/or apoptotic cell death
Disease ex that results from ribosome dysfunction
Diamond Blackfan Anemia
Describe Diamond Blackfan Anemia
mutation in ribosomal subunit protein; fewer erythroid progenitors; production of RBCs impaired; severe anemia
Why is it believed that some organelles arose from endosymbiosis
organelle genome & double membrane
The mitochondrial genome encodes for
tRNAs & mRNAs for translation of mitochondrial genome; proteins for oxidative phosphorylation
Functions of mitochondria
energetic roles; metabolic synthesis roles (nucleotides, lipids, heme); signaling roles
Mitochondria are key regulators of programmed cell death & enact this response by
leakage of cytochrome-C that trigger apoptosis
Known genetic abnormalities of mitochondria are most often evident where
high energy tissues-> CNS, muscle, visual, auditory
Causes of mitochondria diseases
nuclear or mtDNA mutations
Mitochondria DNA genetic disorders are acquired how
maternally inherited
Sperm mitochondria is used for what
propellant
Heteroplasmy refers to what
variation in mutant mitochondrial load depending on how many mitochondria are in the particular oocyte
Causes of Sensory Ataxic Neuropathy in Golden Retrievers
mutation in mitochondrial gene & impaired mitochondrial function in all tissues
Signs of Sensory Ataxic Neuropathy in Golden Retrievers
mild to moderate pathology; wobbly gait; postural deficits; diminished spinal reflexes
Mutation that causes Sensory Ataxic Neuropathy
(triangle)T5304 in the Tyrosine tRNA gene which results in low levels of Tyrosine tRNA & inhibits translation of mitochondrial genes
Parasites may have a non-photosynthetic plastid that is essential for
parasite metabolism
Plastids have their own what
ribosome (prokaryotic in nature)
Certain drugs (like clindamycin) can do what
inhibit the prokaryotic plastid ribosome
Function of cytoskeleton
gives cells shape; network of protein tubes & filaments
Smallest of the three tubes/ filaments discussed
microfilaments
Largest of the three tubes/ filaments discussed
microtubules
Structure of microfilaments
double helix of polymerized actin
Properties of microfilaments (flexible? directional?)
semi-flexible & directional
Roles of microfilaments
structure, adhesion, movement, & cell division
Structure of intermediate filaments
woven “rope-like” bundle of keratin, vitamins, etc
Properties of intermediate filaments (flexible? directional?)
in b/w semi-flexible/ rigid & non-directional
Roles of intermediate filaments
tension bearing, mechanical stability, & cell/ECM or cell/cell adhesion
Structure of microtubules
hollow cylinder of polymerized alpha-beta tubulin dimers
Properties of microtubules (flexible? directional?)
rigid & directional
Roles of microtubules
cell division, intracellular transport, & flagella/ cilia
Actin is made of what
globular subunits that polymerize into filaments
How is actin involved in cell division
cleavage furrow
Microfilaments are used to support & shape what
plasma membrane at cell periphery
Microfilaments are involved in adhesion of what
cytoskeleton to ECM
How are microfilaments involved w/ movement
actin polymerization of myosin motor proteins
Different directional arrangements of microtubules
gel-like network; tight parallel bundle; contractile bunde; dendritic network
Describe actin treadmilling
constant flux-> polymerization/ depolymerization
simultaneous gain & loss of monomers-> filament stays the same length
Describe dynamic instability of microtubules
constantly polymerizing/ depolymerizing
rapid alteration necessary for support of dynamic cellular processes
Proteins ex of intermediate filaments
keratin, laminins, & desmins
What are intermediate filaments specific to
cell-specific
Cause of Epidermolytic Hyperkeratosis
splice mutation in keratin 10 gene; results in a frameshift mutation & truncated protein
Symptoms of Epidermolytic Hyperkeratosis
causes skin to be fragile & prone to blister; increases pigmentation
Laminin does what
supports nuclear envelope
Dystrophin does what
scaffolding protein that links actin to ECM of muscle cells
Cause of muscular dystrophy
exon 50 deletion leading to a frameshift/ truncated protein
Genetic basis of muscular dystrophy
X-linked recessive
In the experiment discussed, how was the Cas9 & guide RNA transported to muscle cells
adeno-associated virus
Outcomes of study
1) repair of double strand break in dystophin exon 51 restores reading frame
2) single nucleotide addition resulted in some incorrect nucleotides in exon 51, but then correct reading frame
3) double deletion upstream lost exon 51, but restores reading frame
Gated trafficking route
cytosol to nucleus
Transmembrane trafficking route
from cytosol to mitochondria or ER
Vesicular trafficking route
from ER to golgi to late endosome/ lysosome/ early endosome/ secretory vesicles/ cell exterior
What proteins are inserted into the ER through a membrane translocon
those w/ a signal peptide
What proteins are released into the ER membrane
those w/ a transmembrane domain
How is cargo transported b/w compartments
in vesicle packages that bud & fuse from membranes
Protein folding is assisted by
ER chaperones
Proteins are transported to the golgi for
modification & sorting
What proteins stay in the ER
those w/ retention signals
What proteins leave the ER
those w/ exit signals
Condition for proteins to be able to leave the ER
must be folded correctly
Cause of Cystic Fibrosis
(triangle)F508 in chloride channel results in a minor defect in folding that prevents proteins from leaving ER
Does the chlorine channel still function is Cystic Fibrosis
yes, but it cannot reach the plasma membrane
Symptom of Cystic Fibrosis
thick mucus in lungs
What mediates vesicle formation
coat proteins
How do coat proteins form vesicles
recruit cargo via receptors & bend membranes to form vesicles
What guides vesicles to target membranes
rab proteins
What enables fusion of vesicles
SNARE proteins
Target for transport from golgi to lysosome
hydrolytic enzymes
Signals needed for hydrolytic enzymes
mannose 6-phosphate & decreased pH
Describe constitutive exocytosis
involves newly synthesized soluble proteins for secretion & newly synthesized plasma membrane fusion
Is constitutive exocytosis regulated
no, unregulated membrane fusion
Describe regulated exocytosis
involves secretory vesicle(molecuole) w/ secretory proteins
How is regulated exocytosis controlled
by hormones or neurotransmitters
Describe receptor-mediated endocytosis
involves uptake of specific macromolecules from extracellular millieu; receptors recycled to cell surface
Describe phagocytosis, a type of endocytosis
uptake of large particles; ex: macrophages, neutrophils, & dendritic cells
Cause of disease from Botulinum toxin
SNAREs are cleaved at neuromuscular junction, which prevents release of acetylcholine
Symptom of Botulinum toxin
flaccid paralysis
Exercise Induced Collapse occurs most often in what breed
labs
Cause of Exercise Induced Collapse
mutation in gene for dynamin-1; vesicle recycling can’t keep up / periods of high activity; synaptic tranmission cannot be sustained