Mcat 3 Flashcards
How ligase enzymes work?
Catalyzes addition or synthesis reaction between two molecules by coupling them with the hydrolysis of energy rich bonds such as those between ATP phosphate group.
What is receptor enzymes?
Are transmembrane proteins that catalyzes chemical reactions in response to ligand binding. Upon ligand binding to the extracellular domain of the proteins conformational change occurs that allows the intracellular domain to become catalytically active. Antagonists are molecule that bind to receptor proteins and reduce the overall response to the normal ligand (agonist), either through competition for the same binding site or by other means.
Receptor tyrosine kinases are one of most common type of receptor enzyme that dimerize and phosphorylation each other when ligands bind.
How hypothesis test is performed?
It assess the validity of a claim made about 2 groups.
H0- theorizes that there is no difference between these 2 groups
Ha- rivals the null by claiming that a difference does exist.
P values evaluate how well the data support Ho, assuming Ho is true. Statistical significance is determined by p value is equal or less than alpha, the predetermined level of significance. In general alpha is set to equal to 0.05
What is conformational stability of a protein? How it can be measured?
Is it’s ability to maintain its 3D folded forms and can be measure by the melting temperature Tm, at which half of the proteins in solution are folded and half are denatured. Conformational stability doesn’t necessarily affect protein function as long as the protein is maintained at a temperature that allows proper folding
What is hills coefficient numbers for positive, negative and no cooperativity?
n>1 positive cooperativity and have sigmoidal dependence on substrate concentration.
n=1 no cooperativity hyperbolic shape
n is between 0-1: negative cooperativity even more hyperboltic shape.
Hills cooperativity is always positive value
Derivation of lineweaver burk equation from Michaelis- Menten equation?
Michaelis- Menten equation: Vo=Vmax [S]\Km+[S]
Reciprocal equation: 1/Vo=km+[S]/Vmax [S]\
Lineweaver burk equation: 1/Vo=km/Vmax 1/[S] + 1/Vmax
Generic equation: y=mx+b
** Michaelis Menten equation is also: Vo=kcat[E][S]/km+[S]
Vmax=kcat[E]
What Upward shifts in the y intercept and leftshift in x intercept corresponds to on lineweaver burk plot!
Decreased Vmax and decreased km
What bond proteases break?
Peptide bonds in proteins via hydrolysis reaction. During peptide hydrolysis a water molecule is used to cleave CN bond in the peptide linkage
What is the formula for rate constant and enzymes change the rate constant?
K=Ae^-Ea/RT
Enzyme increases the reaction rate in both forward and reverse directions
What are the three assumption Michaelis Menten equation relies on?
- The free ligand approximation- [S] is constant during the reaction. It is only true during the initial phase of the reaction.
Substrate can also be depleted when it binds to the enzyme to form enzyme substrate complex . To fix that the total concentration of enzyme in the solution should be smaller than any substrate concentration tested. - the steady state Sumption - states that the concentration of ES remains consistent over the course of the reaction. once concentration of substrate becomes significantly depleted, ES levels decrease and the reaction slows.
- Irreversibility assumption-
States that reaction proceeds only in the forward direction and product does not get converted back to substrate. But once product accumulates the reverse reaction occurs at non-negligible levels and further slow the net rate of product formation
What is attribution theory!
It suggests that individuals tend to explain behavior their own or that of others as resulting from internal or external causes.
Internal or dispositional attribution’s describe behavior to personal factors such as personality ability or attitude. The external or situational attributions ascribe behavior to environmental factors such as task difficulty, presence of others or lack
How enzymatic reactions that involve more than one substrate form?
2 most common mechanisms:
1. Formation of ternary complex which can form in a random order or specific order
2. Ping pong mechanism - always ordered. One substrate binds to enzyme first and reacts, changing the structure of the enzyme itself. This substrate then leaves the active site, allowing 2nd substrate to enter and react, restoring the enzyme to its original form.
Which inhibitors bind to enzyme and enzyme substrate complex with equal affinity?
Noncompetitive inhibitors
What shortens and what doesn’t during muscle contraction?
Shortens:
1. I band - consists of only actin ( thin) filament.
2. H band- consists of only myosin (thick) filaments
Doesn’t change:
A band - which consists of both actin and myosin filament, marks the length of the myosin filaments.
Other lines that is on the sacromeres;
M line - marked the center of each sacromere
Z line - line delineates the boundary between each sarcomere
What are the main four tissue types in human body?
- Epithelial tissue - lines surfaces, protection, absorption, filtration and secretion. Eg skin, lining of hollow organs (digestive tract, trachea)
- Muscle tissue - voluntary and involuntary (cardiac and smooth muscle) movement. Eg skeletal, cardiac. Smooth
- Connective tissue - support and protection, attachment tissues, insulation, thermoregulation, transport eg bone, blood, fat, tendons/ligaments, cartilage
- Nervous tissue- transmission and receipt of electrical signal, response to internal and external stimuli. Examples are brain spinal cord and nerves
Is muscle tissue is a connective tissue?
All the connective tissue comes into contact with muscle tissue, muscle is not considered to be a type of connective tissue
What is sarcoplasmic reticulum
Is specialized endoplasmic reticulum found in skeletal muscle fibers. It stores Ca2+ necessary for skeletal muscle contraction to occur. A specific Ca channel permits diffusion of Ca out of the SR, and a specific ATPase pumps Ca from the cytosol back into the SR
What is pyruvate dehydrogenase complex and how it works?
Is an enzyme composed of a 3 subunits E1, E2, E3. It catalyzes the oxidative decarboxylation of pyruvate to form acetyl CoA, along with the reduction of NAD+ to NADH. During this process, electrons passed from one subunit to next until they can be transferred to NAD+. This transfer is facilitated in part by the cofactor lipoic acid.
How multiple polypeptide chains (subunits) of proteins can be separated in reducing SDS gel?
In their native form, many proteins consist of multiple polypeptide chains (subunits) and are know as multimers (eg dimers; trimers, etc). Reducing SDS gel separate multimers subunits by size. Identical subunits migrate the same distance and form a single band whereas distinct subunits migrate different the distances and form separate bands.
How is western blot works?
Western blot analysis is a technique used to detect the presence of a specific proteins. It is performed by gel electrophoresis of the protein of interest, followed by a transfer to protein binding membrane and intubation with antibodies specific to the protein of interest. Primary antibody or a label secondary antibody is then detected by florescence or chemiluminescence.
What is an anomeric carbon
The carbon that has two bonds to oxygen
What is glycosidic bond
Is a bond between anomeric carbon of a carbohydrate and any other biological molecule including proteins lipids nucleotides and other carbohydrates. Single carbohydrate can participate in multiple glycosidic bonds, one through its own and anomeric carbon (the carbon carbon that is bonded to two oxygen) and others through bonds from its hydroxyl groups to the anomeric carbon of other sugars.
What is sphingolipids?
They are a structural lipids that help influence the fluidity and curvature of biological membrane. It has hydrolyzable bond and nonhydrozible bond. Has one single fatty acid acyl chain with hydrolyzable head.
The long hydrocarbon chain of the sphingosine head group cannot be readily hydrolyzed and sphingolipids are not primary means of energy storage. They
What is liver and platelets do together?
Platelets form a plug at the site where a blood vessel has been damaged. Blood clotting factors that have been synthesized in the liver in the inactive form then participate in a cascade that that leads to blood clot
How long- bones grow in length?
By process of where chondrocytes (cartilage producing cells) divide and produce collagen to which calcium phosphates attaches to form hardened bone. This process stops when linear growth of long bones is complete. Chondrocytes located at the interface between long shaft (diaphysis) and the widened ends (epiphyses) of long bones
What is cervix?
Is the most inferior portion of the uterus and serves as the opening into the vagina. During childbirth the cervix thins and the fetus passes through the cervix into the vagina.
What muscle uterus has?
It is muscular organ responsible for protecting and nourishing the embryo and fetus. It is lined with inner layer called endometrium which changes thickness at different points in the monthly uterine cycle. It has thick layer of smooth muscle (myometrium) involved in contractions during child birth.
What is morphogens?
Are signaling molecules that change patterns of embryonic cell differentiation in a concentration dependent manner. Interfering with the signaling pathways induced by morphogens can change patterns of differentiation in an embryo.
What is senescence?
Is a natural aging process during which cell acquire damage and eventually diminish in function over time. Over time this aging process can cause cells to diminish in function. This may result from the degradation of chromosomes ends (telomeres) that occur over time. But some cells (eg stem cells express an enzyme telomerase, a reverse transcriptase that allow synthesis of chromosomes ends and the prevention of sensescence (cell immortalization)
What is cell immortalization?
Occurs when the cells adapt to aging in away that allow them to continue dividing indefinitely, unlike typical (mortal) cells.
What molecules regulates checkpoints in cell cycle?
Molecules called cyclind and cyclin dependent kinases. If cells have abnormalities that can’t be repaired, these cells will undergo apoptosis rather than completing the cell cycle.
What are the different phases of mitosis?
Prophase - characterized by condensation of chromatin and nuclear envelope disintegration
Metaphase- in which chromosomes align in the metaphase plate (central region of the dividing cell) and become attached to spindle fibers.
Anaphase - in which shortening of spindle fibers causes sister chromatids to separate and migrate away from one another.
Telophase- characterized by reversal of condensation of chromatin and nuclear envelope reformation
What is tissue regeneration
Is the regrowth of the same functional tissues or organs previously present in an organism after loss due to injury. For example the human liver can regenerate after it has been damaged.
What is DNA sequencing is used for?
To determine the nucleotide sequences of DNA
How southern blot works?
- DNA is isolated and cut into smaller fragments by restriction enzymes
- The purified DNA fragments are separated by size via gel electrophoresis and then denatured.
- DNA fragments are transferred from the gel to a blotting membrane and immobilized
- The membrane is incubated with a single strand of DNA probe complementary to the DNA sequence of interest. If the sequence of interest is present, the probe will bind to it (hybridize). The label allows regional detection of the probe.
- Sample is washed to remove unbound prompts
- The researchers determine if the visual signal is present. A visual signal indicates that hybridization occurred, meaning the sample contain the DNA sequence of interest. The lack of visual signal means the target DNA sequence is absent.
What is prostrate do in male reproduction system?
A gland that produces prostatic fluid containing enzymes necessary to prevent the coagulation of sperm in the vagina.
What is bulbourethral glands do in male reproductive system
Glands that secrete thick, alkaline mucus to lubricate the tip of the penis. The alkalinity of the mucus neutralize acids in the urine to protect the sperm from the acidic environment of the urethra
What is seminal gland do in male reproductive system?
Accessory glands that produce the largest portion of seminal fluid
What are the order of human embryo develops?
Fertilization - formation of single celled zygote
Morula formation - zygotes undergoes successive mitotic divisions (cleavage) to form a ball of cells known as a morula
Blastulation - the morula is transformed into a hollow ball of cells knows as the blastocyst. At this stage, embryo implant in the uterine wall. The blastocyst consist of two layers, the trophoblast (hollow cell sphere) and inner cell mass
Gastrulation - the double layered blastocyst becomes a triple layered gastrula. It is through gastrulation that developing embryo forms germ layers.
Neurulation - nervous system develops. Neural tube becomes the central nervous system.
The remaining portions of neural fold are know as the neural crest, give rise to most of the peripheral nervous system
What is the steps of fertilization?
- Sperm reaches oocyte- the sperm weaves past follicular cells the corona radiata
- Sperm contact- sperm binds receptors in the Zona pellucida, a thick matrix of glycoproteins that surrounds the oocyte
- Acrosome reaction- the acrosome is a specialized vesicle filled with hydrolytic enzyme, located in the sperm head. When this enzymes are released, the zona pellucida is degraded, enabling the sperm to reach the oocyte’s plasma membrane
- Fusion - the plasma membranes of the oocyte and sperm are fused.
- Sperm contents enter oocyte - the nucleus, mitochondria and a pair of centrioles enter the oocyte
- Cortical reaction - the contents of the cortical granules in the oocytes are released into the space between plasma membrane and the zona pellucida, fusing with the plasma membraneS this hardens the zona pellucida into a protective envelope, blocking additional sperm from entering
What happens in neurulation?
Is the formation of nervous systems. The notochord, a mesodermal cylindrical structure, releases signals promoting the extenders above to thicken and form neural plate. Neural plate folds inward, forming neural groove and then edges of the plate (neural folds) converge to create the neural tube.
Neural tube is the precursor to CNA, then punches off the ectoderm. The remaining sections of neural folds not included in the neural tube comprise the neural crest which migrate away from the tube and toward the periphery of embryo to give rise to most of the PNS
Examples of germ layer derivatives?
Ectoderm- give rise to the nervous system and develops into the integumentary system which includes hair, skin, nails and the lining of the mouth, nostrils and anus. Epidermis, neurons, melanocytes
Mesoderm - gives rise to the circulatory system, muscles, bones and parts of urinary and reproductive system. Myocytes, osteocytes, and erthrocytes.
Endoderm- gives rise to accessory digestive organs (eg liver, pancreas) as well as the lining (epithelium) of the digestive and respiratory tracts. Mucous cells, islet beta cell, aveolar cells
What is different potency of cell development?
Totipotent stem cells, found in only in zygote and in the embryo up to its eight cell stage. Can give raise to both placental and fetal cells.
Pluripotent stem cells are the cells of inner cell mass of blastocyst. Can give rise to only fetal cells. (Any three primary germ layers.
Multipotent - found in both adult and fetus. It is specific resident cell are preserved in each developing tissue and function to replace damaged/ages cells throughout the organism’s life span. They are able to differentiate only into the specialized cells of certain tissues
What is inductive signaling in cell fate?
Cell fate is influenced by inductibe signaling between cells in the early embryo. In inductive signaling, an inducer (the signaling cell) releases chemical signals that act on competent neighboring cells by regulating the expression of specific genes required for cell determination.
What is three segment of sperm?
Head - containing acrosome (encapsulates the tip of the nucleus and is Rich in specialized lysosome like enzyme for piercing the outer shell of an oocyte during fertilization) and nucleus.
Mid piece - packed with mitochondria, also contains pair of central micro tubules and extend down the length of the flagellum.
Tail
What is overall developmental pathways of sperm?
Spermatogonia undergo mitosis to two daughter cells. One remains spermatogonia stem cell to maintain the line and the other one differentiates into spermatocyte which goes under meiosis 1 and 2 become spermatids.
Then it becomes matured spermatozoa through series of morphological changes.
Spermatogonium- spermatocyte- spermatid- spermatozoon
How is the process of oogenesis happens?
Is a hormone driven process and it involves mitosis and 2 meiotic divisions.
Before birth (5 months gestation) oogonia (germ cells, diploid) goes through mitosis and become primary oocytes. It goes though 1st meiotic division but arrested in meiosis 1 until puberty. During puberty normal mentrual cycle hormones stimulate some primary oocytes to resume differentiating into secondary oocyte. However, prior to fertilization secondary oocytes are arrested in metaphase II of meiosis.
What is differences between spermatogenesis and oogenesis?
They involve cells that undergo meiosis 1 and 2. However, oogenesis in females begins in the embryo and ends at menopause. Whereas spermatogensis in males doesn’t begin till puberty and continues throughout male’s life. They occur without interruption and produces similarly sized daughter cells. 4haploid sperm cells results.
Oogenesis arrested at certain stages and produce unequal size. 1haploid ovum plus 2-3 polar bodies that eventually degenerate.
How body regulates its water content?
By sensing blood volume, osmolarity and pressure. Special sensors ( like stretch receptors) monitor the degree of strain stretching in the heart(blood volume) and transmit this information to the hypothalamus which then sends signal to posterior pituitary to adjust ADH.
What hormones are released from anterior pituitary gland?
FLAT PEG
FSH
LH
Adernocorticad simulating hormones
Thyroid simulating hormone
Prolactin - milk production
Endorphin
G- growth hormone
PEG- direct hormone
What posterior pituatary hormones
ADH antiduratic hormone
Oxytocin
Those are made in hypothalamus and stored in posterior pituitary gland
How two pituitary glands differ in releasing of the hormones?
Anterior pituitary is derived from epithelial cells from the developing roof of mouth and contain grandular endocrine cells.
Posterior pituitary is derived from ectodermal neural tissues in the developing brain and doesn’t contain glandular endocrine cells. Its hormones are transported to axon terminals and stored in vesicles. Depolarization causes release of hormones into blood vessels.
What are the main appetite hormones?
Leptin - appetite suppressed
Ghrelin - appetite stimulated
What are the classifications of hormones?
Peptide hormone - small proteins, consist of amino acids linked via peptide bonds
Steroid hormones - are lipids derived from cholesterol that has been modified via a series of chemical reactions
Amino acid derived hormones - molecules derived from either tyrosine or tryptophan
Another scheme of classification of hormone is based on their influence on other hormones:
Direct - act directly on target cells to elicit nonendocrine responses
Tropic - can target endocrine tissues to influence the secretion of another hormone
Some hormones act as both direct and as tropic hormones
What is the main regions of phospholipids?
Consist of polar head region and non polar tail region. The polar head consists of glycerol, a phosphate and terminal group that is linked to phosphate. Non polar tail consists of two fatty acid lined to the remaining two carbons of glycerol.
What are the three enzymes that is irreversible in glycolysis
Hexokinase
Phosphofructosekinase 1
Pyruvate kinase
Those can’t be used in gluconeogeneis so they are bypassed by distinct enzyme catalyzed reactions unique to gluconeogenesis.
Glucose 6 phosphatase
Fructose 1,6 biphosphatase
Pyruvate carboxylase, phosphoenolpyruvate carboxykinase
What is calcitonin and parathyroid hormone do?
The thyroid gland is responsible for helping to regulate basal metabolism and calcium level. The thyroid gland secretes calcitonin, synthesized from c cells. It reduces free calcium levels in the blood.
It reduces osteoclast activity
It reduces ca reabsorption in kidneys.
It antagonize parathyroid hormone which serves to increase the free calcium levels in blood.
What is antiduretic hormone do?
Maintains fluid homeostasis when blood pressure is low by stimulating the insertion of aquaporins in the membrane of kidney collecting duct cells. This leads to increased water reabsorption which raises the overall blood volume and blood pressure.
What is effect of aldosterone on kidney function?
Aldosterone promotes Na+ reabsorption in distal tumble and collecting duct. Interstitial fluid becomes more concentrated, water reabsorption increases via osmosis. Filtrate becomes more negatively charged due to Na+ reabsorption, promoting secretion of K+ and H+
What are the main types of hormones
- Peptide hormones: dissolved in plasma of the blood, receptor located on cell membrane, after binding activation of second messenger system happens.
Examples: insulin, glucogen,vasopressin (ADH), adrenocorticotropic hormone. - Steroid hormone: bound to carrier protein in blood, receptors located in cytosol or nucleus, in response regulation of gene expression happens.
Examples: cortisol, androgens, estrogens. - Amino acid derivative hormones: 1. Catecholamines: dissolved in plasma of the blood, receptors located on cell membranes. Activation of second messenger system happens.
Examples: norepinephrine epinephrine - Thyroid hormones: bound to carrier protein in the blood, receptor located in nucleus, regulation of gene expression, examples: thyroxine T4, triiodothyrine T3
How endocrine signaling happens?
Hormones are secreted into the bloodstream by specialized cells and transported throughout the body via the circulatory system. Once the hormone reaches its target tissue; it alters cellular function in one of the following ways:
Water soluble (hydrophilic) hormones generally bind to a cell surface receptor and initiate a second messenger cascade, leading to changes in protein activity (eg enzyme, membrane channels)
Water insoluble (hydrophobic) hormones generally diffuse across the lipid bilayer of the plasma membrane and bind to cytosolic receptor to ultimately regulate gene expression in the nucleus.
Hormones can effect the function of diverse and distant tissues in the body. Any cell type that expresses a hormone receptor will respond to serum levels of the hormone
What is the function of liver cells?
- Regulation of blood glucose via glycogenesis, glycogenolysis, gluconeogenesis
- Storage of glycogen, mineral (iron) and vitamins
- Synthesis of macromolecules such as plasma proteins (clotting factors and albumin), fats, ketone bodies and cholesterol.
- Production and secretion of bile
- Breakdown/ detoxification of numerous drugs and metabolic waste products (bilirubin, ammonia)
What is hypothalamus do?
Is the brain structure located inferior to the thalamus that regulates the synthesis and secretion of multiple classes of hormones. It services as the interface between the nervous and endocrine systems by processing both cortical inputs from brain and sensing the plasma concentration of numerous hormones.
What is SRY gene?
Testosterone production in males is related to the presence of the sex determining region Y (SRY) gene on Y chromosomes, a sex chromosome that exists alongside one X chromosome in male cells. It controls male sex determination and promotes development of testes where testosterone is produced.
Hypoglycemia triggers which hormones?
Glucagon and epinephrine.
1. Autonomic nervous system: Hypothalamus sends sympathetic nerve impulses to adrenal medulla which secretes epinephrine in response. Epinephrine promotes glycogenolysis.
2. Hormone glucagon is secreted from the alpha cells of the pancreas. It promotes gluconeogenesis (the synthesis of glucose from other molecules) and glycogenolysis
How does G protein activate adenylate cyclase?
Glucagon acts on target cells by binding its stimulators G protein coupled receptor on the cell membrane and including the adenylate cyclase/cAMP second messenger.
The G protein attached to transmembrane cell surface receptor is composed of three subunits alpha beta and gamma.When inactive, the alpha subunit is bound to GDP which is then replaced with GTP on ligand receptor binding.
The GTP bound G a dissociate from the beta and gamma subunits and proceeds to activate adenylate cyclase, an enzyme that catalyzes the conversion of ATP to cAMP, a second messenger. aCAMP then activates protein kinase A which subsequently phosphorylates the proteins necessary to produce ligand specific physiological effects.
Where is Leptin and ghrelin released from?
In energy rich state (high concentration of glucose and lipids), hormone Leptin is released by white adipose tissue. This triggers feelings of satiety by communicating to the hypothalamus that the stomach is full thereby suppressing appetite. In energy poor state ghrelin is released by stomach gasteric cells to trigger hunger and food seeking behavior via the hypothalamus.
What is somatostatin do?
Delta cells of pancreas produces them. It is a hormone that has a generalized effect on digestive function and has been shown to suppress insulin and glucagon release
What is external intercostals and inter costals do when breathing?
During inspiration external intercostals contract, elevate rib cage, reducing the pressure by increasing intrapulmonary volume.
During expiration internal intercostals contract, depress rib cage, increasing the pressure by decreasing intrapulmonary volume.
The external intercostals are inspiratory muscles
The internal intercostal are expiratory muscles
Why alveoli is efficient at gas exchange?
To their structure and extensive surface area. The small size and sheer number of alveoli in the lungs provide an enormous surface area available for gas exchange. The destruction of alveolar walls in emphysema is expected to decrease the lungs’ ability to perform respiratory gas exchange
What is asthma do to body?
Is due to allergen hypersensitivity can be identified by temporary airway inflammation which causes the bronchioles to narrow. The narrowing of airways increase resistance to airflow which decreases the volumetric rate of forcibly exhaled air. The narrow airways May also trap air in the lungs, decreasing the total volume air that can be exhaled
The regulation of respiratory rate is most sensitive to?
PCO2 in the blood. PCO2 of blood sensed by central and peripheral chemoreceptors. These receptors directly detect the [H+] in the blood, which is dependent on the perils pressure CO2 in the blood through the bicarbonate buffer system.
CO2+H2O=H2CO3=HCO3- +H+
What is intrapleural space?
Is the thin space between the lungs and the thoracic wall. The contraction of the diaphragm and the elevation of the rib cage decreases the pressure in the intrapleural space, causing the lungs to expand.
How inspiration occurs?
Is primarily initiated by the diaphragm l. The diaphragm is a sheet of skeletal muscle below the lungs and when it is relaxed it curves upward to adopt a dome shape. When the diaphragm contracts, it flattens, pulling down on the lungs and causing them to expand. In addition, the external intercostal muscles ( aground of muscles at the rib cage) and scalenes (muscles attached to ribs near the neck) can contract to elevate the rib cage (thereby preventing the diaphragm from pulling the lower ribs inward) and further expand the lungs
What is coughing and sneezing help for respiratory system?
Are forms of forced expiration that help clear trapped particles from the pharynx
What is cilia do in respiratory system?
Are hair like organelles that are found in some specialized cells. They are involved in the defense mechanisms of the respiratory system.
- nasal hairs- fillet out relatively large particles before they enter the respiratory tract.
- mucociliary escalator- specialized cells lining the upper respiratory tract produce mucus, a thick and sticky secretion that traps inhaled bacteria and particles. Ciliated cells beat synchronously to sweep foreign bodies trapped in mucus up the pharynx. From the pharynx, those foreign bodies can be coughed out or swallowed and destroyed by the harsh acidity of the stomach
-phagocytosis - alveolar macrophages are the type of white blood cell that engulf and digest
How blood vessel injury can be repaired?
- Formation of the platelet plug- endothelial damage exposes connective tissue (collagen fibers) normally present outside the blood vessel. Circulating cell fragments called platelets (derived from the bone marrow) readily bind to these collagen fibers, aggregating to form a platelet plug. In addition, bound platelets and endothelial cells continue to release signals that enhance platelet aggregation.
- Strengthening of the clot- clotting factors are specialized proteins that become activated in response to platelet aggregation and signaling factors outside the vessel. Activated clotting factors induce processes that lead to the formation of enzyme thrombin which induces protein strands to form an adhesive mesh like structure over the platelet plugs
What is gene therapy
A technique in which functional gene is introduced into a patient’s cells to replace a mutant gene. The new gene can the. Be transcribed and translated into functional proteins. A common gene therapy method uses retroviral vectors to insert functional gene copies into the stem cells of patients exhibiting specific genetic mutations
What is capillaries?
Are the smallest of the blood vessels. Their small diameter and thin walls allow for the efficient exchange of gases and water with the interstitial fluid. The balance between several forces determines the net direction of fluid movement in capillary beds.
Capillary hydrostatic pressure
Capillary oncotic pressure
Interstitial fluid hydrostatic pressure
Interstitial fluid oncotic pressure
What is systolic and diastolic pressure?
Systolic- heart muscles contract and pump blood into arteries. Arterial pressure increases. Increased volume of blood flowing through the arteries on contraction of the heart exerts increased pressure on the arterial walls. Arterial blood pressure is highest during systole and is measured as the systolic blood pressure.
Diastolic pressure - heart muscles relax and fills with blood returning to the heart via veins. Arterial pressure decreases and it is lowest.
What are the different blood components?
- Plasma- 90% water
10%- electrolytes, gases, hormones, nutrients, metabolic water, blood proteins - White blood cells and platelets
- Red blood cells
How hemoglobin’s affinity for oxygen works?
Hemoglobin consists of four subunits each of which can exist in either of two conformations:
T- tense, low oxygen affinity
R- relaxed, high oxygen affinity
Oxygen’s binding to one subunit stabilizes the subunit’s R state. The bound subunit then positively cooperates with other subunits inducing them to change from T to the R conformation and making oxygen finding easier
What is Bohr effect?
During exercise, individuals experience an increase in the H+ concentration in the blood. (ATP +H2O =ADH +P+ H+)
Accumulated H+ ions can bind to hemoglobin and recur its affinity for oxygen in a phenomenon known as the Bohr effect. This reduced affinity appears as the right shift in the oxyhemoglobin dissociation curves
What is the effect of 2,3 BPG on oxyhemoglobin dissociation curve?
It decreases oxygen affinity by stabilizing the oxyhemoglobin conformation. Increasing concentrations of 2,3 BPG produce a right shift in the oxyhemoglobin dissociation curve and faster oxygen delivery to tissues.
Bisphosphoglycerate mutase converts 1,3 Bisphosphoglycerate into 2,3 Bisphosphoglycerate
What is left shift on the oxyhemoglobin dissociation curve?
It signifies an increase in the affinity of hemoglobin for oxygen. This affinity is inversely related to CO2 and H+ concentrations. Therefore left shift in the ODC often indicates lower CO2 and/or acid levels in blood
How reactive oxygen species can damage the cell?
Oxidation stress occurs when reactive oxygen species such as hydrogen peroxide are overly abundant near cell membrane. ROS can react with lipids in cell membrane and cause membrane ruptured also known as lysis. When this occurs in red blood cells; hemoglobin can leak out as and denature, becoming nonfunctional and causing hemolytic anemia
What is hematocrit?
Measured as a percentage of the total blood volume, indicates the amount of red blood cells in a blood sample. Hemolysis induced by oxidative stress can reduce hematocrit
What does lymphatic system do?
It collects protein containing fluid leaked from blood capillaries and transports it back to the bloodstream.
In addition, large lipid droplets absorbed by the small intestine are also transported to the bloodstream via lymph vessels. Fluid is collected by lymph capillaries, flows into larger lymph vessels and is transported into lymph ducts that drain into veins near the heart.
It also involved in the immune system
Which situation will increase pH levels in blood?
Increased alveolar gas exchange increases blood pH.
How obesity can effect ventilation?
Ventilation is movement of air into and out of the lungs, facilitate gas exchange in alveoli. Anatomical features (eg body position, amount of adipose tissue) can influence respiratory and cardiovascular functions.
What is cardiac output?
Is the volume of blood pumped by the heart per minute. This volume is pumped by the right ventricle to the lungs and by the left ventricles to the rest of the tissues in the body.
Cardiac output = mean arterial pressure/ vascular resistance
What are the three segments of large intestine?
Cecum- receives chyme from the ileum of the small intestine
Colon- absorb water and electrolytes from material not digested by the small intestine. Concentrates feces (human waste product composed of water, indigestible material, bacteria, bile and enzymes.
Rectum - stores feces until excretion through the final opening in the rectum, the anus.
What is the main three components of cytoskeleton of eukaryotic cells?
Microfilaments 7nm
Intermediate filaments 10nm
Microtubules 25nm
What is intermediate filaments do?
Composed of several protein types (eg keratin, lumen) and perform:
- work with Microfilaments to determine cellular shape.
- make up the nuclear lamina (inner lining of nuclear envelope)
- assist in anchoring organelles to specific compartments within the cell
- provide crucial support for the cell to be able to withstand mechanical forces. (Eg compression)
What is Microfilaments do?
Are made out of actin protein subunits organized into double stranded rods. They help determine the overall shape of a cell and assist in some cellular locomotion. They also responsible for muscular contractions and forms the cleavage furrow during cytokinesis.
What is microtubules do?
Are made of alternating alpha and beta tubulin subunits organized into hollow tubes. They form mitotic spindle during the cell division process. They also involved in movement within the cell. Also forms cilia and flagella.
What is sequence of gastrointestinal tract?
Mouth
Esophagus
Stomach - chyme is formed
Small intestine
Large intestine
Nutrient absorption is affected by?
The diversity of intestinal bacteria (gut flora), the surface area of the small intestine, and the functions of intestinal proteins (digestive enzyme, nutrient transporters, structure proteins)
What are the excretory system organs?
Kidney
Ureter
Bladder
Urethra
What are the muscles that control urination?
It is under control of both smooth and skeletal muscle along the urinary tract (the system for removing urine from the body). Layer of smooth muscle lining the bladder known as the detrusor muscle is relaxed while urine is stored in the bladder. During this storage process, two sphincter muscles are contracted so that urine can’t exit the body:
1. The proximal sphincter muscle is known as the internal urethral sphincter (IUS). The IUS is composed of smooth muscle and is under involuntary control by the autonomic nervous system
2. The distal sphincter or the external urethral sphincter EUS is compressed of skeletal muscle and is under voluntary control by the somatic nervous system.
What is insulin do?
Food digestion leads to increased glucose level and stimulates specialized cells of the pancreas called beta cells to release insulin. It is a glucose metabolism hormone that decreases the concentration of glucose in the blood. It accomplishes by promoting glucose uptake by tissues (eg adipose, muscle) and decreasing liver glucose production (via gluconeogenesis, glycogenolysis) while at the same time promoting liver glycogen formation (glycogenesis)
What is intestinal lumen?
The cavity ( hooson zai) of intestine. Digested food is inside. Surrounding it there is epithelial cells, surrounding that interstitial fluid, then capillary.
How nutrients are absorbed into the body?
They absorbed by intestinal epithelial cells and transported into surrounding interstitial fluid before diffusing into capillaries, increasing osmotic pressure interstitial fluid and subsequently in the blood plasma
How active transport of NaCl is necessary for reabsorption of salt in renal medulla?
Ascending limb of henle is highly permeable for NaCl but impermeable for water. Initially NaCl is passively reabsorbed into the medulla as filtrate moves up the ascending limb. However, as the ascending limb nears the cortex, NaCl is actively transported from the filtrate into the medulla, preserving the medulla’s high salt concentration
What does colon absorb?
Electrolytes (eg sodium, chloride) and additional water from the mass of undigested material
What does enzyme lined immunosorbent assay detect??
Elisa can detect and quantify proteins. Initially a primary antibody (linked to reporter enzyme) is added, which bind to the antigen (protein). The samples are washed to remove unbound proteins, and the reporter enzyme is added. The enzyme-substrate reaction creates a product that results in a quantifiable/ detectable signal
Where is transcription factors located?
They bind to specific DNA sequences and control the rate of gene transcription. They are initially transcribed in the nucleus but are translated in the cytoplasm. Inactive transcription factors which are not bound to their DNA substrate, are found in the cytoplasm. However, during cell signaling, the nuclear localization sequence found in transcription factors allows nuclear import proteins to direct transcription factors back to the nucleus via nuclear pores to alter gene expression.
What does bile do in digestion of lipid?
The liver synthesizes bile, a nonenzymatic solution stored in the gallbladder and released into the small intestine to aid in the mechanical digestion of lipids. Bile is composed of bile salts, bile pigments and cholesterol. Bile salts act as detergents to solubilize fats during digestion, they possess both a hydrophobic region that associates with the surface of lipids and a hydrophilic region that associates with water. Consequently, bile salts break down large lipid globules into smaller droplets (micelles) in a process known as emulsification. Emulsified lipids chemically digested by pancreatic lipase
How pH of the stomach is maintained
By gastric juice which is composed primarily of hydrochloric acid which is secreted by parietal cells in the stomach. This acidic environment is required for protein digestion and to kill harmful bacteria. When gastric juice mixed with food (chyme) enters the duodenum, it is neutralized by bicarbonate ions (produced in the pancreas) and bile (released from storage in the gallbladder).
What are the sphincters in gastrointestinal tract?
At certain sections along the gastrointestinal tract, sphincters or rings of muscle, divide the tract into segments with distinct functions. Ingested food passes from the esophagus into the stomach through the cardiac sphincter and from the stomach into the duodenum through the pyloric sphincter.
What cells stomach secrete?
- G cells (gastrin) signals parietal cells to secrete hydrochloric acid.
- Parietal cells: A. Hydrochloric acid B. Intrinsic factor (aids in absorption of vitamin b12 in the ileum.
- Chef cells- A. Pepsinogen B. Gastric lipase
- Mucous cells - mucus and bicarbonate, protects the stomach walls from auto digestion by gastric juice, which contains acids and proteases
What is peritoneum and peritoneum cavity?
Peritoneum comprises two membranes that line the abdomen; the parietal layer which line the abdominal wall, and the visceral layer which covers the abdominal organs. The peritoneal cavity is a potential space between the parietal and visceral layers of the peritoneum.
What is perineum?
Is the area between anus and the scrotum (in males) or vulva (in females).
What product liver contribute that can be used in duodenal lumen?
Bile is a substance synthesized by the liver and stored by the gallbladder. When released into the duodenal lumen, it aids in the mechanical digestion of lipids. Other functions of the liver include blood glucose regulation, macromolecule synthesis, molecular storage and detoxification.
Which cells in small intestine involved in absorption of nutrients?
It occurs across epithelial cells. Any undigestible material passes to the large intestine
How gut bacteria helps with digestive system?
The large intestine contains many bacterial species that aid digestive process. Some of these bacteria can process ingested foods that would be undigestable otherwise into molecules that can then be absorbed by the body and used for energy. Other bacterial species in the large intestine synthesize certain vitamins.
What is neutral theory of molecular evolution?
The majority of genetic mutations are neutral which means they don’t effect the fitness of an organism. Within species, these neutral mutations are randomly fixed or lost due to genetic drift and occur at fairly constant rate over time
What is molecular clock model?
Is based on the theory that most genetic mutations are neutral and occur at fairly constant rate across organisms. It allows researchers to measure evolutionary time by analyzing random changes in the genome over time. For example species that diverged more recently from a common ancestor have accumulated fewer mutations across the short time and are therefore more genetically similar to one another (more closely related).
What are the similarities between meiosis and mitosis?
- DNA synthesis occurs prior
- In a given organism, parent cells have the same chromosomes number
- Divided into same stages PMAT
- One parent fell undergoes cell division to produce multiple daughter cells
What are the different kinds of evolution?
- Parallel evolution- occurs when two species more closely related (descended from a recent common ancestor) continuous to evolve the same characteristics to adapt to similar environments.
- Divergent evolution- occurs when two species descended from a recent common ancestor inhabit contrasting environments and evolve distinct characteristics that allow them to better adapt to their differing environment pressures.
- Convergent evolution l- leads to similar characteristics in distinctly related species that are exposed to similar pressures
What are the hardy weinberg equilibrium equations?
P+q=1
P^2+2pq +q^2=1
What is genetic linkage?
Refers to the tendency of alleles in close proximity to remain on the same chromosome and be inherited together by offspring. This tendency occurs because of fewer crossover events between these loci during meiosis, resulting in a greater number of haploid gametes with nonrecombinant genotypes
How truncated protein is produced from translation?
Nonsense mutation is a mutation in which nucleotide change creates a premature stop codon, causing early translation termination and production of a truncated (shortened) protein.
Where is erythropoietin produced?
The adult kidney produce it. It is a hormone that signals bone marrow to increase red blood cell production
When dominant mutated allele can survive eradication from gene pool by natural selection?
Can remain in the gene pool if the organism’s fitness remains unaffected, even when the deleterious alleles reduce survival after the reproductive years. In addition, deleterious recessive alleles evade elimination by natural selection through phenotypic masking in heterozygotes.
