Biochemistry/Physiology Flashcards
What makes a sugar a reducing sugar?
If the oxygen atom on the first carbon is not attached to anything, it can be reduced.
What is a GAG?
glycosaminoglycans
What are the most abundant GAGs?
chondroitin sulfate
What is the most heterogenous GAG
Keratan sulfate
What is the most abundant GAG in a joint?
hyluronate
What is maltose?
two glucose
What is lactose?
glucose and galactose
What is sucrose?
glucose and a fructose
Where does final digestion of carbohydrates occur?
small intestine
What type of bond connects the monosaccharides in sugars like maltose, lactose and maltose?
O-glycosidic bonds
What is D-glucose?
a monosaccharide and a aldohexose
What is the most common configuration of sugars?
The D form (as opposed to the L form)
What are the two major components of starch?
amylose and amylopectin
What are the linkages of starch?
unbranched: a -1,4 linkages
branched: a-1,6 linkages
What are the linkages in glycogen?
a-1,4 linkages
Where is chondroitin sulfate normally found?
cartilage, aorta, cell membranes, tendons and ligaments,
What in the freak is a Dextran?
a polysaccharide of glucose that is produced extracellularly by bacteria and yeast using the enzyme glucosyl transferase, which cleaves sucrose into fructose and glucose and will link the glucose together, leaving a by product of fructose.
Which bacteria can produce dextrans?
strep mutans
What is the photopigment called that rods contain?
rhodopsin, which is retinal + opsin
What mineral is required to make rhodopsin?
vitamin A. This makes retinal, which is combined with opsin to make rhodopsin. Vit A deficiency can lead to night blindness.
Which part of the eye is like a shutter on a camera?
iris
Which part of the eye does the majority of bending of light for focusing an image?
the cornea (not the lens)
What part of the eye becomes “cloudy” in cataracts?
The lens
What things can cause conductive hearing loss?
stuff in the auditory canal
otosclerosis
anything in the middle ear
What things can cause sensorineural hearing loss?
stuff in the inner ear ototoxic drugs Meniere disease Acoustic neuroma Presbycusis
What is presbycusis?
hearing loss with age
What is miosis?
constriction of pupil of eye
What is mydriasis?
Dilation of pupil of eye
What is myopia?
nearsightedness, far things are blurry and are focused in FRONT of the retina
What is hyperopia?
farsightedness, close things are blurry, but far things can also be blurry and are focused BEHIND the retina.
What is albumin and what is unique about it?
it is a blood protein. It is very compact, which means it doesnt really effect the viscosity of the blood.
it makes up 60% of the plasma proteins, but provides 80% of the colloid osmotic pressure because it is so hydrophilic.
Basically, water loves it, it is small, and there is a lot of it.
What does PTH do?
parathyroid hormone increases serum calcium. It increases absorption of calcium in the gut and osteoclast activity in the bones
What does Calcitonin do?
Decreases serum calcium. It increases osteoblast activity.
How much of plasma is water?
91%
What is syneresis?
liquid that separates from a gel that is solidifying.
What happens if there is trauma to a tissue as far as the clotting pathway?
- Tissue factor converts VII to VIIa
- VIIa activates factor X to Xa using calcium
- Xa combines with V to make prothrombin activator
- Prothrombin activator turns prothrombin into thrombin
- Thrombin turns fibrinogen into fibrin, which forms the clot
Where is iron absorbed in the GI?
duodenum
How is iron stored in the body?
forming complexes called ferritin and hemosiderin
How does iron get from your diet to a cell being stored?
it is absorbed in the duodenum, and combines with apotransferrin to form transferrin in the bloodstream. This is a loose binding though so as it travels through the bloodstream, it can disconnect and go into any tissue for storage.
What is hemochromatosis?
iron storage disease that results in iron-containing pigments in peripheral tissues. It causes bronzing of the skin, diabetes and weakness.
Type O is the universal ______
donor, because it has no AB antigens. These people have anti A and anti B antigens, so can only receive type O blood.
What is the universal receiver for blood transfusions?
Type AB because they lack anti-A and anti-B antibodies
What are the two forms of hemoglobin?
T and R (tense and relaxed). Tense hemoglobin has a weaker affinity for oxygen (in the capillaries)
A right shift in the oxyhemoglobin dissociation curve indicates what?
a decrease in oxygen affinity to hemoglobin
What type of shift in the oxyhemoglobin dissociation curve happens during low pH?
right, so more oxygen gets released and more CO2 can get eliminated.
What type of shift in the oxyhemoglobin dissociation curve happens during increased temperature?
right
What type of shift in the oxyhemoglobin dissociation curve happens during decreased CO2?
left, so that co2 will not get eliminated as quickly.
What are the two major parts to a hemoglobin molecule?
the globin part: has 4 polypeptide chains (2 alpha and 2 beta)
the 4 ring-shaped heme molecules (non protein groups)
How many oxygen molecules can a hemoglobin hold?
4 molecules of O2
Where does the CO2 bind on a hemoglobin molecule? Where does the O2 bind?
CO2 binds to the protein part
O2 binds to the non-protein part
What are the types of Hemoglobin and what is each one?
MCASH
hemoglobin M: associated with methemoglobinemia
hemoglobin C: lysine instead of glutamic acid
hemoglobin A: 2 alpha and 2 beta (normal in humans)
hemoglobin S: valine replaced glutamic acid (sickle cell)
hemoglobin H: four beta chains (alpha-thalassemia)
Where is erythropoietin formed?
90% in the kidneys, the rest in the liver
What is polycythemia?
a ton of RBCs in the blood, making it really viscous
What do erythrocytes contain that aid in function of the RBC?
hemoglobin and carbonic anhydrase
What are the two important types of tubular glands in a stomach mucosa?
oxyntic glands and pyloric glands
Where are oxyntic glands located?
The proximal 80% of the stomach
Where are pyloric glands located?
the distal 20% of the stomach
What cells make up the oxyntic glands of the stomach and what do they do?
Mucous neck cells: secrete mucous
Chief cells: secrete pepsinogen and gastric lipase
Parietal (or oxyntic) cells: secrete HCl and intrinsic factor
What is intrinsic factor?
it is a mucoprotein that is required to absorb vitamin B12. it is secreted by parietal cells in the stomach.
What are the cells that make up pyloric glands of the stomach and what do they do?
G cells: secrete gastrin
Mucous cells: secrete mucous, bicarbonate, and pepsinogen
What are the 3 functions of brunner’s glands?
- secrete alkaline mucous
- secrete bicarbonate
- inhibit parietal cells by secreting urgastrone
What three hormones cause pancreatic secretions?
- Ach: increases GI activity
- Cholecystokinin: for bile
- Secretin: helps with alkalinity
Pancreatic enzymes that are secreted in the duodenum are called what?
Zymogens and they are inactive until they get to the small intestine
What is cobalamin?
vitamin B12
What are the three processes that take place in the stomach before the food can move on to the intestines?
propulsion- moves food toward the pylorus
grinding - breaks food to <2mm
retropulsion - moves arge chunks away from pylorus
What are the three phases of gastric HCl secretion?
Cephalic phase - HCl is secreted at the sight and smell of food. 30% of HCl happen here.
Gastric phase: 60% of HCl happen here
intestinal phase: 10% happen here
What causes dissociation of the actin-myosin complex?
ATP binding to the myosin head.
The finer the movement, the ______ number of muscle spindle fibers in the muscle.
greater
What is the difference between the golgi tendon organ and the muscle spindle fiber?
golgi tendon organ is a protective reflex to protect the tendons. It INHIBITS alpha motor neurons.
The spindle fiber, when stretched, activated the alpha motor neurons.
What is the function of basal ganglia?
To control complex patterns of motor activity
What other structures do basal ganglia work with?
the cortex and corticospinal motor system
What are types of structures that are considered basal ganglia?
the striatum, globus pallidus, substantia nigra etc…
What brain structure is stimulated when there is a reduction in core body temperature and what action does this produce?
posterior hypothalamus will produce shivering
What is the corpus callosum?
It is the mass of nerve fibers that connect the two hemispheres of the brain.
Which has a higher blood flow per minute, aorta or capillaries?
They are the same
What is the diameter of an arteriole?
30-400 micrometers (NOT mm!)
HIV/AIDS has what enzyme that can effect DNA?
reverse transcriptase
How do ribosomes differ in bacterial vs human cells?
bacterial: 70s ribosomes (30 and 50)
human: 80s ribosomes (40 and 60)
What direction is DNA formed, from 3’ to 5’ or 5’ to 3’
DNA is read by a DNA polymerase from 3’ to 5’ and as it reads it, it makes a copy from 5’ to 3’. So the complimentary strand is formed from 5’ to 3’.
What is topoisomerase?
it uncoils “supercoiled” DNA when replicating
What is DNA gyrase?
It takes a strand of newly formed DNA and recoils it.
What is a helicase?
it unwinds and DNA helix for replication
What is the difference between a nucleotide and a nucleoside?
nucleotides have a nitrogen base, a ribose/deoxyribose and a phosphate group, but a nucleoside doesnt have the phosphate.
Eating a diet rich in purine bases leads to the accumulation of __________. Why?
Uric acid. purine bases in the diet are turned to uric acid by xanthine oxidase.
What is the start codon? What is another name for it?
AUG or “methionine”
What are the stop codons?
UAA, UAG, UGA
What is the first heart enzyme to appear in the bloodstream following an MI?
creatine kinase
What are the 3 heart enzymes useful in a diagnostic test for MI’s?
Creatine Kinase (CK) Lactate Dehydrogenase (LDH) Aspartate transaminase (AST)
What is the coenzyme in transaminase reactions?
pyridoxal phosphate (PLP)
What is an oxidative deamination reaction?
it is a reaction under aerobic conditions where an amino acid is converted to a keto acid for energy.
What are the products of an oxidative deamination reaction of glutamate?
alpha ketoglutarate and free ammonia
What is a key enzyme in the production of aqueous humor in the eye?
carbonic anhydrase
What are the components of the electron transport chain?
- complex 1 (FMN): recieves electrons from NADH. transfers them via Fe-S to
- Coenzyme Q: receives e- from FMN and transports them to Complex 3. (skips complex 2)
- Complex 2: receives e- from FADH2 and transports them to complex 3
- Complex 3: has cytochromes a,b, and c.
- Cytochrome C transfers e- to complex 4.
- Complex 4 passes e- to oxygen.
- ATP synthetase
What vitamin is complex 1 derived from?
riboflavin
Which complex is a part of the krebs cycle?
complex II (succinate dehydrogenase)
What is a proenzyme?
an inactive precursor of the enzyme
what is an apoenzyme?
an inactive enzyme because a coenzyme was removed from it
Which enzyme dissolves blood clots?
plasmin. it will cleave the peptide bond in fibrin to dissolve the clot
How is a zymogen activated?
Zymogens are inactive due to a protein that is attached to it. So cleavage of that protein will activate the enzyme.
What is another name for amylase?
ptyalin (amylase breaks down starches, just FYI)
Which is faster, a-amylase or b-amylase?
a-amylase
Which amylase will cleave a-1,6 glycosidic linkages?
gamma amylase
What does glucose-6-phosphatase do?
it turns glucose-6-phosphate into glucose.
What organs is glucose-6-phosphate present in?
liver and kidneys but NOT skeletal muscle!
What is gluconeogenesis?
making glucose from lactic acid or amino acids
What is the substrate for glycogen synthesis?
UDP-glucose (the non-reducing end of glycogen is the other substrate)
What is the difference between a non-competative and un-competitive inhibitor?
both bind to an allosteric site on an enzyme, but the uncompetitive inhibitor will ONLY bind to the enzyme IF a substrate is already attached.
What converts Trypsinogen into its active form trypsin?
Trypsin itself, or enteropeptidases
How is pepsinogen activated?
By the low pH in the stomach
What else can trypsin activate other than trypsinogen?
ALL of the pancreatic enzymes
What is the bone enzyme?
alkaline phosphatase
What does the bone enzyme do as osteoblastic activity increases?
It increases in the blood serum
What is alkaline phosphatase derived from?
osteoblasts
What is an enzyme in the blood that is used in the diagnosis of organophosphate poisoning?
plasma cholinesterase
What enzymes are used to diagnose liver disease?
alanine transaminase and aspartate transaminase
What enzyme can help detect bile obstruction?
y-Glutamyl transferase
what enzyme will be elevated in prostate cancer?
PSA (prostate-specific antigen) and Acid phosphatase (ACP)
If an apoenzyme combines with a cofactor, what does it make?
A haloenzyme (the active form of an apoenzyme)
Which enzyme is vital to tissue respiration and is a cofactor for the enzyme pyruvate dehydrogenase?
Thaimine pyrophosphate
What is another name for growth hormone?
somatotrophic hormone
What is growth hormones inhibitory effect?
It inhibits the action of insulin metabolism
What cells in the body have both androgen and FSH receptors?
Sertoli cells
What is the most important target of cAMP?
protein kinase A
What degrades cAMP?
phosphodiesterases
What is the best-known stimuli for increasing the rate of TSH?
exposure to cold
Which part of the hypothalamus is oxytocin and ADH made?
ADH - supraoptic nuclei
Oxytocin - paraventricular nuclei
What receptors does insulin bind to?
tyrosine-kinase receptors on skeletal muscles.
What transporters work to bring glucose into the cell?
GLUT-4
What stimulation could cause BOTH insulin and glucagon release into the bloodstream?
increased levels of amino acid
What is the collective group of names for hormones secreted due to acid chyme in the duodenum that inhibit the stomach?
enterogastrins (like cholecystokinin and GIP)
Where is aldosterone secreted?
in the zona glomerulosa of the adrenal cortex.
What does aldosterone do?
it acts on the distal tubule of the kidney to reabsorbe sodium and water, and excrete potassium.
What is ANP and what does it do?
Atrial Natriuretic Peptide, causes sodium and water to be excreted in the urine (opposite of aldosterone)
How do oral contraceptives work?
They prevent the rise in luteinizing hormone which prevents ovulation.
What effect does TSH have on the body?
- normal growth and development (especially the brain)
- affects metabolic processes and rate of metabolism
- increases oxygen consumption and heat production
What amino acid is a precursor to catecholamines?
tyrosine
What does gastric inhibitory peptide do?
It is released into the upper small intestine by mucosa after a person eats a meal and begins increasing insulin in anticipation of increased blood glucose.
It also slows down the stomach when the upper small intestine is full.
It increases lipase activity in adipocytes
Type II diabetics are not responsive to which hormone, other than insulin?
GIP
What are the three zones of the adrenal gland cortex and what hormone is secreted at each zone?
Gooey Fart Rippers All Can’t Announce
Zona Glomerulosa - Aldosterone
Zona Fasciculata - Cortisol
Zona Reticularis - Androgens
What is secreted in the adrenal gland medulla?
epi and norepi
Mineralcorticoids have
an aldehyde group at C-18
What is unique about estrogens structure?
ring A is aromatic
What are the functions of cortisol?
promotes gluconeogenesis, lipolysis, breakdown of protein, glycogenolysis
What disease can happen due to excessive cortisol release?
Cushing’s Syndrome
What unique symptom is associated with Cushing’s Disease?
moon facies
What is another name for somatostatin?
Growth hormone inhibitory hormone
What functions do somatostatin have on the body?
They inhibit a bunch of stuff like:
Growth Hormone Insulin Glucagon many other GI hormones and more...
What cell produces prolactin?
lactotropes
What does phenylethanolamine-N-methyltransferase do? Where is this found?
it turns norepinephrine into epinephrine. it is ONLY found in the adrenal medulla
What hormones is tyrosine a precursor to?
catecholamines and Thyroid Hormone
Which hormone would cause increase in number of aquaporins in the kidney tubules?
ADH
What is a neurilemma?
The sheath of schwann cells that wrap around axons in the PNS. These allow the nerves to regrow if damaged, but only in the PNS!
What is another name for a nerve block caused by local anesthetics?
nondepolarizing nerve block
What is the site of action for local anesthetics
the lipoprotein sheath of a nerve
What is the difference between spatial summation and temporal summation?
spatial: multiple places of excitation at the same time
temporal: rapid succession of excitation at the same point
What does an increase in diameter of a nerve fiber do to the speed of nerve conduction?
it increases it
Is glycine excitatory or inhibitory?
inhibitory
Is serotonin excitatory or inhibitory?
inhibitory
What is monoamine oxidase?
an enzyme that aids in created excess neurotransmitters at postsynaptic sites.
What two structures make up the striatum?
caudate nucleus and putamen
What two structures make up the lentiform nucleus?
The putamen and globus pallidus
Is the basal ganglia generally excitatory or inhibitory for motor movements?
inhibitory
What is the system called that includes structures from the basal ganglia?
extrapyramidal system
What are the receptors for Ach called?
nicotinic and muscarinic
What is another name for the corticospinal tract?
pyramidal tract (as opposed to the extrapyramidal tract)
What is the “tract” called that cranial nerves are a part of?
corticobulbar tract
The corticospinal tract travels to the pyramids of the medulla and most of it decussates to run down the spinal cord. The part that decussates is called what? The part that remains ipsilateral is called what?
The part that decussates is called the lateral corticospinal tract or crossed pyramidal tract
The part that does not decussate is called the anterior corticospinal tract or direct pyramidal tract
What is an exteroreceptor?
A sensory receptor that detects stimuli external to the body
What is another name for a motor neuron?
“Final common pathway”
What is adaptation in a sensory receptor?
a change in the way the receptor responds (like you get used to a smell because your receptors desensitize)
What are meissner’s corpuscles?
sensory receptors to light pressure, fine touch, or low frequency vibration
what are Krause’s corpuscles?
sensory receptors to touch, low frequency vibration, or cold
What are Ruffini’s corpuscles?
sensory receptors to crude and persistant touch or heat
What are Pacinian corpuscles?
sensory receptors to deep pressure, high frequency vibration or stretch
What is an mEPP?
miniature end plate potentials. These are small depolarizations at the motor end plate of muscle. If enough of them occur, a full-fledged “End Plate Potential (EPP)” will occur and the muscle will contract.
What is the rubrospinal tract deal with?
Its a motor tract in the spine that deals with coordination of body movements
What is the vestibulospinal tract?
a motor tract that helps with balance
what are funiculi?
The areas of the white matter in the spinal cord
Where do the following transporters reside? GLUT-1 GLUT-2 GLUT-3 GLUT-4 GLUT-5
GLUT-1: RBC's and blood brain barrier GLUT-2: Liver and pancreas GLUT-3: neurons GLUT-4: muscle and adipose tissue GLUT-5: intestine and testis
What is massive, systemic edema called?
anasarca
What percentage of sodium chloride is considered isotonic?
0.9% solution or 5% glucose solution
What quality do inorganic salts give to bone?
They help the bone withstand compression
What quality do collagen fibers give to bone?
They increase the tensile strength of bone
What type of bond is a peptide bone?
A covalent bond
How much of a body is made up of water?
How much of that water is intracellular vs extracellular?
60%
40% - intracellular
20% - extracellular
What temperature does the skin need to be to start sweating?
37 degrees
What is the first antibody present during an infection?
IgM
What is the most common antibody in the body?
IgG
What is the most important antibody to a secondary infection?
IgG
Which antibody activates compliment?
IgM
Which antibody is the second most abundant antibody?
IgA
What is the main function of the proximal convoluted tubule?
reabsorbs 2/3 of filtered salt and water and all filtered organic solutes like glucose etc…
What is the main function of the descending limb of the loop of Henle?
it is permeable to water, but NOT to salt
What is the main function of the ascending loop of Henle?
It is not permeable to water, and salt is actively pumped out of the urine to the interstitial fluid.
What is the main function of the distal convoluted tubule?
Its mainly regulated by the endocrine system and will do what the hormones tell it to do.
How does the kidney help regulate the body’s pH?
It secretes H+ and reabsorbs bicarbonate. It can secrete either acidic or alkaline urine.
How is GFR increased?
- vasodilation of afferent arterioles (increase whats coming in)
- Vasoconstriction of efferent arterioles (decrease whats going out)
- decreased hydrostatic pressure in Bowman’s capsule
- Decrease plasma colloid osmotic pressure
How much glomerular filtrate and urine excretion happen in one day?
150-250 L of glomerular filtrate
1-2 L of urine
Where is the primary location for glutamine to be turned into ammonia?
kidneys
Which enzyme directly catalyzes urea formation in a cell?
arginase
How is the action potential different in cardiac muscles vs skeletal muscle.
It has a plateau, which makes it last 15 times longer in cardiac muscle
What are the 2 reasons why there is a plateau in cardiac muscle action potentials?
- Cardiac muscle has an additional channel called the slow calcium channel. They remain open for longer before repolarization.
- The permeability for potassium is 5x lower during an action potential in cardiac muscle, making potassium take longer to enter the cell.
How does the refractory period differ between atria and ventricles?
atria are only .15 seconds and ventricles are .25 to .30 seconds.
How do the refractory periods differ in skeletal muscle vs cardiac muscle?
skeletal muscle is faster, and allows contractions to happen before the muscle has relaxed.
The first heart sound is the closure of what valve?
What about the second heart sound?
first heart sound is the closure of the AV valves
The second is the closure of the semilunar valves
What does a P wave represent in an ECG?
atrial depolarization
What does a T wave represent in an ECG?
Ventricular repolarization
What does a QRS complex represent in an ECG?
ventricular depolarization (and also atrial repolarization)
What would you suspect if you see extra P waves before each QRS complex on a ECG?
partial heart block
What results on an ECG would you see in a complete heart block?
P waves and QRS complexes each at there own rhythm
What is the Bainbridge Reflex?
Also known as the atrial reflex. It’s a positive feedback mechanism in which you get an increased HR due to increased atrial pressure.
