AMS Exam 2 Flashcards
What is transamination
one of two main processes of Amino acid metabolism
the process of removing an amine group from one amino acid and adding it to a metabolic intermediate to create another amino acid
Important transamination examples:
pyruvate → alanine;
α-ketoglutarate → glutamate;
oxaloacetate → aspartate
With transamination, pyruvate and intermediates of the citric acid cycle provide the carbon skeletons needed for the synthesis of nonessential or dispensable amino acids.
What is the role of ZPA
The zone of polarizing activity (ZPA)
is an area of mesenchyme that contains signals which instruct the developing limb bud to form along the anterior/posterior axis.
Limb bud is undifferentiated mesenchyme enclosed by an ectoderm covering.
Eventually, the limb bud develops into bones, tendons, muscles and joints
The master gene for this regulation is the sonic hedgehog whose product is secreted by these cells
What is the Fab portion of an antibody for?
Antigen binding
What makes up antibodies?
2 heavy chains and 2 light chains
There is an Fab portion (top of “y”) and a Fc portion (bottom of “Y”)
There are constant portions and variable portions
The two sides of the Y are held together by disulfide bonds
Describe IgG antibodies.
IgG = 70-75% of antibodies
can pass throught the placenta
involved in activating the comlement system
provides long term protection because it persists for months or years after the antigen that has triggered their production - bacteria, virus, binds antigens to enhance phagocytosis by other cells
IgG is found throughout the body, mainly in most of the bodily fluids
IgG is a much more specific antibody to the antigen, therefore it binds the antigen more tightly
IgG takes the body longer to create but it stays within the body on memory cells
Describe IgA antibodies.
IgA binds antigens on microbes before they invade tissues
Causes antigen aggregation
Are teh first defense for mucosal surfaces such as intestines, lungs and nose
What percentage of T cells are TCR2 cells
90-95% of T cells
heterodimer of alpha and beta chains
MHC dependent in their recognition of antigen
subdivided into CD4 and CD 8 cells
What are the functions of the complement system
Kill pathogens
Opsonization
Complement proteins coat the outer surface of the pathogen and attract macrophages
Membrane attack complex
Enhance inflammation
Explain C5a in classical pathway
It comes from C5
When C5 is cleaved by C5 convertase (C4b2a3b)
it becomes C5a and C5b
C5a is a chemo attractatn for macrophages and neutrophils
C5a binding to these cells primes the cells for mediating their host defense functions
It increases the expression of adhesion molecules on leukocytes and the vascular endothelium so that leukocytes can squeeze out of the blood vessels and enter the tissue (diapedesis).
It also causes neutrophils to release toxic oxygen radicals for extracellular killing; and it induces fever.
Describe dendritic cells
These are antigen presenting cells (APC’s)
Process and present antigens to T cells
Express MHC II
Phagocytosis
can act as a messenger between innate and adaptive immunity
Functions of T cells
Recognition of antigens through t cell receptors
helper and regulatory finctions
activate B cells
activate other cells of the immune response through cellular interactions or production of regulatory factors
Killing of target cells (foriegn cells, infected self cells, transfromed or aged cells)
Complement proteins
Soluble Proteins in the blood, part of the innate immune system
30+ types of proteins produced by the liver
Circulate in blood in inactive form – so they don’t attack the body
Become activated when they interact with an antigen
Complementary activation cascade
Complementary proteins activate each other
What are the granulocytes
Neutrophils = Multi-lobed, granules,
phagocitize pathogens or debris (50-70%)
Eosinophils = Bi-lobed, granules, kill parasitic worms, role in allergies and asthma (2-4%)
Basophils = single nuclei, lobed, releases histamine, anitcoagulant (<1%)
Describe Unsaturated Fat
Non-Saturated Fat:
Fewer hydrogen bounds bounds to carbons
1 or more double bonds (kinks in the tails)
Liquid at room temperature
Low melting point
Most plant fats are unsaturated or polyunsaturated
Example: Oils
Describe Oligosaccharides
Condensation products of 3-10 monosaccharides
Indigestible à humans lack enzymes to break them down in the small intestine
Most are soluble fibers that help prevent constipation
Describe a Type 4 hypersensitivity reacion?
Type 4 = Regulated by T cells and are delayed reactions to antigens associated with cells
Tuberculin reactions, chronic asthma and contact dermatitis are type 4 reactions
What is deamination
one of two main processes of Amino acid metabolism
the process of removing an amine group and breaking down amino acids
With deamination, after the amino acid gets broken down, the amino nitrogen is excreted as urea
What is WNT Genes
genes that inhibited certain BMP to aid in heart development
What is Bmp (BONE MORPHOGENETIC PROTEIN)
further express dorsal and ventral regions by interacting with signals at the node
- -bmp is secreted as a growth factor in all regions and cells * *if inhibited, mesoderm layer becomes “dorsalized” forming the axial skeleton and notochord. * * if not inhibited (active), the mesoderm becomes “ventralized” to from the urogenital system, the limbs and ventral wall body
What is TBX Genes
transcription factors that specify limb direction and formation
Describe IgM antibodies.
produced during primary immune response
also enhances ingestion of cells by phagocytosis
best at activating complement system
IgM is the immediate antibody that is produced once a human body is exposed to a bacteria, virus or a toxin
IgM is larger in size compared to IgG
IgM is temporary and disappears after a few weeks. It is then replaced by IgG.
IgM is found mainly in the blood and lymphatic fluids.
Describe conjoined twins
overexpression of Goosecoid in frogs causes double-headed tadpoles:
too much goosecoid induces additional head regions
What happens when a Naive B cell is activated
After immunization or infection, Naive B cells become activated and can switch from expressing IgM or IgD on their surface to expressing IgG, IgE or IgA
What is Hox genes
play many roles in development; identity of the pharyngeal arches, limb location on the body
What is chemiosmosis in the ETC
The chemiosmotic theory explains the functioning of electron transport chains.
According to this theory, the tranfer of electrons down an electron transport system through a series of oxidation-reduction reactions releases energy.
This energy allows certain carriers in the chain to transport hydrogen ions (H+ or protons) across a membrane.
Steps in gluconeogenesis
Pyruvate → → → → → Pyruvate carboxylase Oxaloacetate → → → → → PEP carboxykinase PEP
PEP → → Fructose 1,6, bisphosphate (reverse glycolysis)
→ → → → → Fructose 1,6, bisphosphatase
Fructose 6 phosphate
Fructose 6 phosphate → → Glucose 6 phosphate
Glucose 6 phosphate
→ → → → → Glucose 6 phosphatase
Glucose
Systemic defenses of innate immune system
Systemic defenses
The elimination of foreign agents that made it through external barriers
Cellular component- Phagocytes
in acquired immunity - T cells
Soluble (humoral) Component
Antibodies
complemnt proteins
antimicrobial proteins
What results from the trilaminar disc
3 germ layers; Ectoderm, Mesoderm & Endoderm (outer/dorsal, middle, inner)
The dorsal germinal layer becomes the ectoblast/-derm.
The middle germinal layer (3rd germinal layer) becomes the mesoblast/-derm.
The ventral germinal layer receives the name endoblast/-derm.
What is the role of AER
The apical ectodermal ridge (AER)
is a structure that forms from the ectodermal cells at the distal end of each limb bud and acts as a major signaling center to ensure proper development of a limb
FGFs are secreted by the AER
What are APC cells
Antigen presenting cells
These are cells that express the MHC II
These can present antigens to T cells
Langerhans cells in skin
Dendritic cells
macrophages B cells
Describe Acquired immunity
Aquired or adaptive immunity can be active or passive
Active is exposure to deisease or vaccine and build antibodies accordingly
passive is gettting antibosie sfom another sourec ie breast milk placenta etc.
What is Fibroblast growth factor (FGF)
secreted by the node; initiates secretion of nodal from the primitive node that becomes concentrated on the left side; aids in limb growth, bone formation
Describe innate immune system
Activated cells produce their effects via the release of cytokines, complement and other systems: cytokines
What does the Embyroblast become
The embryo
Originate from Morula
inner cells from trophoblast
What are TCR 1 cells made up of
These are T cells
make up less than 10% of t cells
heterodimer of gamma and delta chains
What is the Fc portion of the antibody for?
Effector portion
Describe sacrococcygeal teratoma
tumor of the sacral area
contains every type of tissue derived from all 3 germ layers: gut from endoderm, neural tissue from ectoderm, and bones or teeth from mesoderm
This tumor may be derived from the fact that gastrulation went on too long
Is complement system innate or adaptive
Mostly Innate (both)
C1q part of the C1 complex can assist the adaptive immune response by binding to antigen antibody complexes on the surface of bacterial cells.
In most cases, this would be after the adaptive response has been initiated.
The classical pathway of complement system can also be involved in innate immunity if the complement proteins recognize and bind to the bacterial cell.
What is neurulation
Neurulation is a process in which the neural plate bends up and later fuses to form the hollow tube that will eventually differentiate into the brain and the spinal cord of the central nervous system.
Describe crouzon syndrome
Wide-set, bulging eyes and vision problems caused by shallow eye sockets
Mutation of FGFR2
beak nose, dental, jaw, hearing, cleft, eye issues
Normal intelligence
Describe diapedesis
Process of entering the tissue
attracted to endothelial cells via selectins
and bind via integrins
(this is a prcess of entering the tissue and is known as diapedesis)
Describe a Type 3 hypersensitivity reacion?
Type 3 = Results from the formation of antigens-antibody complexes that settle on tissue and organs in an attempt to remove these complexes underlying tissue is also damaged
Serum sickness and rheumatoid arthritis are type 3 reactions
What is the transverse septum
At start of 4 weeks gestation, there in only one continuous body cavity.
There is partial separation of the body cavity by a layer of mesoderm cells called the septum transversum
It will help to form the diaphragm (considered a major central tendon)
It is derived from the visceral mesoderm surrounding the heart. It is the folding of the head region that carries the septum transversum into the thoracic cavity.
creates the pericardioperitoneal cavities.
Forms the connective tissue of the liver as hepatic cells grow
What are the 2 types of light chains in antibodies?
Kappa and lamda
Describe achondroplasia
Mutation in FDFR3
Short limbed dwarf
Describe Polydactyl
Programmed celll death is interruppted
leaves too many fingers
Describe thalidomide induced limb defects
Disruption of AER
-Dactyl defects
Describe pfeiffer syndrome
Affects the shape of head and face, abnormalities in hands and feet
Mutations
Type 1 = FGFR1 or 2
Type 2 and 3 FGFR2
Most have normal intelligence and life span
What are the molecular signals of differentiation
Anterior visceral endoderm (AVE) expresses the head forming genes thus inducing the cranial region.
Goosecoid—a transcription factor which is the main head induction gene; encodes for the formation of the head
Bmp (BONE MORPHOGENETIC PROTEIN)—further express dorsal and ventral regions by interacting with signals at the node
- -bmp is secreted as a growth factor in all regions and cells * *if inhibited, mesoderm layer becomes “dorsalized” forming the axial skeleton and notochord. * * if not inhibited (active), the mesoderm becomes “ventralized” to from the urogenital system, the limbs and ventral wall body
Chordin—growth factor secreted by goosecoid
Noggin, follistatin, and nodal—growth factors secreted by the node and are proteins that inhibit BMP
Fibroblast growth factor (FGF)—secreted by the node; initiates secretion of nodal from the primitive node that becomes concentrated on the left side; aids in limb growth, bone formation
Nodal—secreted by the primitive node; its concentration on the left side of the embryo helps to establish left-sidedness by enhancing transcription factor, PItX2
PITX2—main transcription factor that induces left-sidedness
Hox genes—play many roles in development; identity of the pharyngeal arches, limb location on the body
TBX Genes- transcription factors that specify limb direction and formation
WNT–genes that inhibited certain BMP to aid in heart development
NKX2.5—the main transcription factor that encodes for heart development
What is Noggin, follistatin, and nodal
growth factors secreted by the node and are proteins that inhibit BMP
Activation of lectin pathway
Triggered by mannan-binding lectin, a normal serum constituent, that binds some encapsulated bacteria
Aka: Triggered by Lectin binding to pathogen surface
Cells: Factor D, Factor B, Prepardin, C3
What are the hypoblast cells
Hypoblast- important for early signaling to establish the cranial-caudal axis. Are eventually displaced
About 1 or 2 days after implantation, the embryo/embryoblast begin to differentiate into 2 layers
The dorsal layer, the epiblast,
and a ventral layer, the hypoblast
Explain C5a in classical pathway
It comes from C5
When C5 is cleaved by C5 convertase (C4b2a3b)
it becomes C5a and C5b
C5a is a chemo attractatn for macrophages and neutrophils
C5a binding to these cells prime sthe cells for mediating their host defense functions
What are the Agranulocytes
Lymphocytes = spherical, single nucleus, mount immune response by direct cell attack or via antibody production (20-40%)
Monocytes = U shaped nucleus, develop into macrophages in tissue and phagcitize pathogens or debris
What is a phospholipid
Glycerol molecule
two fatty acid non polar tails and a phosphate polar head
hydrophobic tails
hydrophilic heads
plasma membrane
External barriers of innate immune system
Physical barriers
skin,cilia
Chemical barriers
lysozymes in teras/saliva, mucin in mucous
Mechanical barriers
Cough, sneeze, flushing of urinary tract
microbial barriers
common flora, (gut, vagina, skin etc)
What cells are most responsible for transplant rejection
T cells
Explain C3a in classical pathway
It comes from C3
When C3 is cleaved by C3 convertase (C4b2a)
it becomes C3a and C3b
C3a is a potent chemo attractant
C3a attracts Mast cells to sites of complement activation.
Binding of C3a to mast cells and basophils induces degranulation and release of histamine.
What percentage of T cells are TCR1 cells
less than 10%
What happens when naive b cells are activated
naïve B cells become activated and can switch from
expressing IgM and IgD on their surface to expressing IgG, IgE or IgA
Describe Neutrophils
Last for 6 hours in circulation
account for 95% of circulating graulocytes and leukocytes
work through phagocytosis, can release granules causing damage to host
first cells to arrive at site of inflammation
(one way journey from bone marrow)
attracted to endothelial cells via selectins and bind via integrins
(this is a prcess of entering the tissue and is known as diapedesis)
Increased count = infection
