principles Flashcards by a pov

the human placenta is comprised of two parts - from which cell population is the fetal part of the placenta derived?

trophoblast

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drug works by binding to an intracellular receptor that then activates gene expression in the nucleus

steroid hormone

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what accurately describes hydrogen bonds

three atoms usually lie in a straight line

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The production of ATP is required to produce the basic currency of energy for all cellular processes. Rapidly contracting human muscle cells start producing lactic acid.
which statement best explains this finding?

the cells have to convert NADH to NAD+

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which statement best described ligand-gated ion channels?

they conduct ions more quickly than carrier molecules

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signals must be transmitted between cells and within cells to maintain homeostasis. a variety of cell surface receptors may perform this function. which statement best describes the G-protein cycle?

signalling is terminated by the hydrolysis of GTP to GDP at the alpha-subunit

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maintaining electrolyte balance in the extra and intra cellular environment is part of normal homeostasis. which statemement describes transport across the cell membrane

sodium-glucose co-transport is an example of secondary active transport

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which underlying physiological mechanism is responsible for signs of being pale, cold and sweaty?

increased sympathetic activity

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what is the risk of a female child inheriting an x-linked dominant inheritance with complete penetrance

100%

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which cell type is the predominant mediator of allergic reactions

mast cell

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immune cell contains granules filled with enzymes such as myeloperoxidase

neutrophil

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HIV patients with enlarged firm but painless right cervical lymph node - biopsy shows multiple granulomata containing langerhans-type giant cells with central caseation

Ziehl-Neelsen stain

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describe the organisms E.Coli

most strains of this organism are common as part of the normal bowel flora, but a few are pathogenic and cause severe gastroenteritis

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describe the mechanism underlying white cell margination in a blood vessel

the vessel dilates reducing flow

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which pathological process does the cervical screening test diagnose

dysplasia

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what type of study would provide the highest quality evidence

meta-analysis of trials

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what is likely to happen in the event of an influenza pandemic?

school closure

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which measure is the most effective way to measure the success of a programme

incidence

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what nerve is damaged if a knife goes into the right side of the root of his neck

phrenic

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what is the inner most layer of the heart

epicardium

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what layer is continuous with the blood vessels connected to the heart

endocardium

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what WBC has granules and is multi-lobed

neutrophil

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what cell has red granules and bi-lobed nucleus

eosinophil

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what cell has a kidney bean/horse shoe shaped nucleus and lacking cytoplasmic granules

monocyte

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which venous system drains blood from absorptive parts of the GI tract and associated organs to the liver?

hepatic portal venous system

what is the name of the blood vessel of the great venous trunk that returns deoxygenated blood from the head and neck to the RA

superior vena cava

what term describes the alternative vascular routes through which arteries connect with each other directly

collaterals

in which organ does ovulation begin?

ovary

what is the long bone in the forearm

ulna

which bones are in the axial skeleton

sternum, skill, vertebral column, thoracic cage

which bones are in the appendicular

upper and lower limbs and shoulder and pelvic girdles

the spherical shape ball of cells without a cavity 3-4 days after the fertilisation of an ovum

morula

formed 5 days after fertilisation and possesses an inner cell mass which subsequently forms the embryo and an outer layer consisting of cells collectively

trophoblast

when is a foetus considered a foetus

week 9 -> birth

when is a blastocyst formed?

4 days after fertilisation- when cavity forms

what is an acrosome

is a secretory vesicle covering the anterior portion of the sperm head underneath the plasma membrane and is a derivative of the golgi apparatus that helps during fertilisation

16 cells in a solid ball contained within the zona pellucida

morula

which describes the single cell stage of the fertilised ovum

zygote

when is an unborn considered an embryo

fertilisation to the end of week 8

when is an unborn considered a conceptus

between fertilisation and week 3

in which sub-cellular organelle are ribosomes produced?

nucleolus

across which cell structure does an electrical impulse travel from one cell to another

gap junctions

where are lipids produced

SER

which avascular, typically polarised tissue, forming cohesive sheets, lines his abdominal cavity

epithelium

what tissue has very long, elongated cells with each cell having multiple nuclei and no abnormality

skeletal muscle

what tissue is described as being packed extracellular bundles of collagen fibres which are arranged in random direction

dense irregular connective tissue

striated cells that are branched and have a single nucleus located near the centre with no abnormality

heart myocytes

which is a form of glia responsible for producing myelin in the CNS

oligodendrocytes

what glia cell supports and maintains homeostasis in the extracellular environment

astrocytes

what are microglia for

immune surveillance cells

what cell produces myelin in the PNS

Schwann cells

what is the total number of ADP molecules that are phosphorylated to ATP during the complete catabolism of glucose to pyruvate

which mechanism is used for ATP synthesis in the glycolytic pathway

substrate phosphorylation

what happens when a stop codon is reached by a ribosome (in the A site)?

a termination protein binds to the codon and is used to release the growing peptide from the P site tRNA. the ribosome then is likely to dissociate

which describes the quaternary structure

the relative orientation of one polypeptide to another polypeptide in a multisubunit protein

what is the direction of synthesis of DNA

from 5' end to the 3' end on both strands

describe buffering capacity

the extent to which a buffer can counteract the effect of added acid or base

describe the reduction of pyruvate to lactate

the rate of reaction is matched by NADH regeneration by glyceraldehyde 3-phosphate dehydrogenase

the substrate concentration at which the reaction velocity is 50% of the Vmax

michealis constant (KM)

increase in Km but no change in Vmax

competitive

decreased vmax and Km

uncompetitive

transcription factor binding to a specific DNA sequence highly ocnserved RNA polymerase II general transcription factor that binds to the core promoter and intitiates the assembly of complexes in prep for transcription

TATA box binding protein

what is an example of an enzyme important for transcription

RNA polymerase

in the normal human heart which receptors mediate the increase in rate and force due to stimulation of the sympathetic division of the autonomic nervous system

B1 receptors

where are all the places B1 receptors are found

heart, kidney, fat cells

G-protein-coupled receptor communicating through the Gs alpha subunit

beta-1 adrenergic receptor

describe the physiology of the heart

by signalling Gs, a cAMP-dependent pathway is initiated through adenylyl cyclase, and this results in potentiation of the receptors function. targeted activation of the b1 receptor in the heart increases SA nodal, AV nodal and ventricular muscular firing this increasing HR and contractility. hence SV, CO increases during physical exercise

an effect of the stimulation of the parasympathetic division of the autonomic nervous system

decreased heart rate through release of acetylcholine

how long would it take a drug obeying first order elimination kinetics with a half-life of 4 hours administered by constant IV infusion to reach steady state plasma conc

20 hours BECAUSE steady state conc is reached in approx 5 half-lives

the rate of elimination of a drug obeying first order kinetics is ____ proportional to the drug conc

directly

what is the resting membrane potential in a nerve cell and what is it maintained by

-70mV | balance of extracellular sodium and intracellular potassium ions

what happens when membrane potential is at -60mV and what is it known as?

in response to stimulus, sodium ions enter the cell through ligand-gated or mechanically-gated channels causing the membrane potential to become less negative THRESHOLD POTENTIAL

why does the membrane potential rise to +40mV

voltage-gated sodium channels open to trigger an action potential with depolarisation

what is a result of the baroreceptor response to decreased MABP

arteriolar vasoconstriction

what is the anterior hypothalamic centre stimulated by

warmth

vasoconstriction of the skin arterioles is caused by ____ nerves

sympathetic

what is a characteristic of a disease due to a heritable mutation in mitochondrial DNA

the condition can only be transmitted from an affected mother to her children

autosomal recessive mode of inheritance characterisitic

where one child is affected in the family, the risk of the next child, to the same parents, being affected in 1 in 4

where is there no male to male transmission of a genetic condition

x-linked recessive disorder

deletion of the long arm of chromosome 5, deletion of the short arm of chromosome 17 and an extra copy of chromosome 8 - what is this in technical description

del(5q), del (17p), trisomy 8

in which part of the chromosome does a robertsonian translocation commonly occur

near or at centromeres

47 XY +21

down syndrome

45 X

turner syndrome

47 XY +18

edward syndrome

47 XXY

Klinefelter syndrome

extra genetic material from chromosome 13

patau syndrome

which protein expressed on the surface of macrophages mediates recognition of bacteria

PRRs

protein that bind directly to extracellular bacteria and cause cell death by osmotic lysis

MAC

which proteins function as an opsonin

C-reactive protein | C3b and IgG

which molecules function as pattern recognition receptors (PRRs)

lectin-like molecules

which immunoglobulin sub-types against Epstein-Barr virus will be useful to diagnose a recent infection?

IgM

which protein is expressed on cytotoxic T cells

CD8

what provides resistance against intracellular microorganisms

t cells

purple

positive

grape like clusters

staphylococcus

gram positive organisms are know to produce ___toxins

exo

the genetic material associated with all the micro-organisms colonising the body

microbiome

which type of pathogen causes malaria

a protozoa

which genra of prokaryote is gram positive

clostridia

fungus that stains as gram positive

candida

what is endotoxin shock caused by

lipopolysaccharide

cell wall antimicrobial

penicillins, glycopeptides, cephalosporins

antibiotics that affect nucleic acids

metrondiazole | ciprofloxacin

antibiotics targeting protein synthesis

aminoglycosides (gentamicin) | tetracyclines (doxycycline/minocycline) and macrolides (erythromycin)

beta-lactam ring to inactivate cell wall transpeptidases

amoxicillin

does vanomycin have a b-lactam ring

no, only amox

what is associated with malignant epithelial tumours in humans

human papilloma virus

carcinoma of the colon with liver metastasis, mutation in a gene that is normally involved in cell cycle arrest and apoptosis, mutant gene can make the tumour resistant to chemo

p53

where is a site of transitional epithelium

urinary tract