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.