Basic Sciences Stuff Flashcards

Question

Lung volumes, 01

Answer 1

**TLC, Total lung capacity**: the volume in the lungs at maximal inflation, the sum of VC and RV. **TV, Tidal volume**: that volume of air moved into or out of the lungs during quiet breathing (TV indicates a subdivision of the lung; when tidal volume is precisely measured, as in gas exchange calculation, the symbol TV or VT is used.) **RV, Residual volume**: the volume of air remaining in the lungs after a maximal exhalation **ERV, Expiratory reserve volume**: the maximal volume of air that can be exhaled from the end-expiratory position **IRV, Inspiratory reserve volume**: the maximal volume that can be inhaled from the end-inspiratory level **IC, Inspiratory capacity**: the sum of IRV and TV IVC, Inspiratory vital capacity: the maximum volume of air inhaled from the point of maximum expiration **VC, Vital capacity**: the volume of air breathed out after the deepest inhalation. **FRC, Functional residual capacity**: the volume in the lungs at the end-expiratory position RV/TLC%, Residual volume expressed as percent of TLC

Answer 2

VA, Alveolar gas volume VL, Actual volume of the lung including the volume of the conducting airway. FVC, Forced vital capacity: the determination of the vital capacity from a maximally forced expiratory effort FEV, tForced expiratory volume (time): a generic term indicating the volume of air exhaled under forced conditions in the first t seconds FEV1, Volume that has been exhaled at the end of the first second of forced expiration FEFx, Forced expiratory flow related to some portion of the FVC curve; modifiers refer to amount of FVC already exhaled FEFmax, The maximum instantaneous flow achieved during a FVC maneuver FIF, Forced inspiratory flow: (Specific measurement of the forced inspiratory curve is denoted by nomenclature analogous to that for the forced expiratory curve. For example, maximum inspiratory flow is denoted FIFmax. Unless otherwise specified, volume qualifiers indicate the volume inspired from RV at the point of measurement.) PEF, Peak expiratory flow: The highest forced expiratory flow measured with a peak flow meter MVV, Maximal voluntary ventilation: volume of air expired in a specified period during repetitive maximal effort

Answer 3

calculated for premature babies OI = (FiO2 X Mean Airway pressure) / PaO2 > 40 - consider ECMO support

Answer 4

**cAMP** = Adrenaline, GHRH, Glucagon, LH, FSH, PTH, TSH **MAP kinase pathway**: Insulin, GH, Prolactin **Ca++/Phospoinositide**: TRH, GnRH, Vasopressin **cGMP**: = Nitric Oxide, ANP **Intra-cellular receptors** = for T3 thyroxine **Cytosolic receptors**: = Steroids (Progesterones, Testosterone, Estradiol, Cortisol)

Answer 5

Corticosteroids Vitamin D Retinoic Acid Sex Steroids

Answer 6

During normal breathing, vagal impulse activity of stretch receptors increases with onset of inspiration dying down as expiration begins. **Stimulation of stretch receptors by maximally inflating lungs in the humans INHIBITS INSPIRATION further** thereby limiting tidal volume and also slows respiratory rate, called as Hering Breuer reflex which is **protective** and important during exercise. It is **inactive in adults until tidal volume increases 1 Liter** - after which reflex increases respiratory rate and shortens inspiration.

Answer 7

Hydrogen ions reduce Hemoglobin’s affinity for oxygen by altering the structure of Hb so that it binds less easily to Oxygen and is known as **Bohr effect**.

Answer 8

Haemoglobin reacts more readily with CO2 to form Carbamino compounds as it releases Oxygen increasing CO2 carrying capacity of blood. Opposite occurs as Hb is saturated with oxygen. Approximately 0.7 ml CO2 per 100 ml is unloaded for 1 mm Hg drop in CO2 pressure. Helps in minimising CO2 changes.

Answer 9

for some genes either maternally or paternally derived, copy is preferentially used (not both) and other is inactivated **Examples** - 1. **Prader Villi Syndrome**: in 70% deletion on paternal chromosome 15, in 30% maternal uniparental disomy ie none from father. Has neonatal hypotonia, Poor feeding, moderate learning disability, Hyperphagia, Obesity, small genitals. 2. **Angelman syndrome**: 80% deletion on maternal chromosome 15, 2-3% paternal uniparental disomy. Happy puppet, unprovoked laughter or clapping, Microcephaly, severe learning disability, ataxia, Broad based gait, convulsions, EEG characteristic **Other examples**: Albrights hereditary Osteodystrophy Becekwith Wiedman Syndrome Russel Silver syndrome Familial Paraganglinomas (Pheochromocytoma)

Answer 10

**IgG**: monmeric, 1,2,3,4 > 75%, crosses placenta **IgM**: pentameric, first to respond to any new infection **IgE**: monomeric, binds allrgens, causes most degranulation involved in Type 1 hypersensivity reactions (inhibited by Omalizumab) **IgA**: dimeric, deficiency associated with auto-immunity as coeliac disease, mucosa association, IgA deficiency is **commonest Primary Variable deficiency**, = levels < 0.05 gms/Lit = presents as recurrent otitis media, pneumonias, Chronic sinusitis, reactions to blood products (check anti IgA antibodies prior to transfusions) **IgD**: monomeric, Hyper-IgD- syndrome is a rare autosomal recessive condition with periodic fevers

Answer 11

Immunoglobulins which precipitates on exposure to cold as in cold fingers. these proteins may clump together at temperatures below 98.6 F (37 C). These gelatinous protein clumps can impede your blood circulation, which can damage your skin, joints, nerves and organs — particularly your kidneys and liver. **Presentation:** most commonly fatigue, joint pain, numbness or weakness, and a particular rash called **purpura** that looks like red spots or purple bruises, usually over the lower legs. **Type I Cryoglobulins** Monoclonal IgM cryoglobulins, causes hyperviscosity as in Waldernstrom's **Type II Cryoglobulins**: mixed mono/ polyclonal cryoglobulins seen with Hepatitis C, chronic infections **Type III Cryoglobulins**: Polyclonal cryoglobulins seen in CTDs as Sjogrens, SLE

Answer 12

**Classic pathway**: Antigen + antibody = C1 complex activation = C1q, C1r, C1s = (C2 to C2a, C4 to C4a) = final common pathway = C5 TO C9 activation = membrane attack complex **Lectin Pathway**: Sugar residues on pathogens activates C2 +C4 then final common pathway follows **Alternative Pathway**: Bacterial, fungal cell wall, causes C3 activation to C3a, C3b =Factor B + D = Final common pathway of C5 to C9 activation = membrane attack complex formation deficiency in common final pathway increases Neisseria infections.

Answer 13

Phase 0 = depolarization and overshoot, initial upstroke Phase 1 = early repolarization to plateau voltage Phase 2 = Action potential plateau Phase 3 = full repolarization back to resting membrane potential Phase 4 = resting membrane potential with gradual depolarization during this phase in pacemaker cells

Answer 14

**Southern Blot**: to transfer DNA fragments from a agar gel to a membrane **Western Blot**: proteins are transferred **Northern Blot**: RNA is bound to a membrane

Answer 15

**Blood agar**: grows most organisms **Chocolate agar**: for Haemophillus, Neisseria **Nutrient Broth**: for anaerobes **Cooked meat Broth**: aerobes, anaerobes **Brain Heart infusion Broth**: for fastidious organisms, fungi **Sabaraud's agar**: for fungi **Anaerobic Blood agar**: Peptococcus, propiniobacterium **Thioglycolate agar**: anaerobes **Lowenstein Jenson medium**: for TB **E coli seeded agar**: for Entamoeba

Answer 16

PVT TIM HiLL 1. Phenyl alanine 2. Valine 3. Tryptophan 4. Threonine 5. Isoleucine 6. Methionine 7. Histidine 8. Leucine 9. Lysine

Answer 17

encoded on chromosome 6 Class I HLA: = A, B, C Class II HLA: = DP, DQ, DR HLA-A3: = Haemochromatosis HLA-B5 = Behcet's disease HLA-B27 = Ankylosis, Reiters, Anterior uveitis HLA-DQ2/ DQ8 = Coeliac disease HLA-DR2 = Narcolepsy, Goodpastures HLA-DR3: = Primary biliary cirrhosis, Sjogrens, Dermatitis herpetiformis HLA-DR4 = Rheumatoid arthritis, IDDM

Answer 18

located on chromosome 6 short arm Encodes for proteins known as HLA which are expressed on surface of variety of cell types mainly leucocytes. Class I HLA (a,b,c) are expressed on virtually all body cells except RBCs and trophoblasts Class II HLA (dr, dq, dp) are expressed on B cells, monocytes, macrophages, follicular dendritic cells Most unstimulated T cells do NOT express class II antigens but they are induced to express them following antigen presentation/stimulation. Class I presents endogenous peptides to T cell receptor of CD8 cells Class II presents exogenous peptides to T cell receptors of CD4 types

Answer 19

G0 phase: most cell in adult tissue are in this phase G1 phase: First gap phase, prior to initiation of DNA synthesis S phase: phase of DNA synthesis G2 phase: second gap phase, errors repaired here M phase: Mitosis phase, which completes cell cycle

Answer 20

**Adrenal Cortex**: **3 layers** Zona GFR-Miner Gluco Andro 1. **Zona Glomerulosa** (Outer): produces mineralocorticoids, 2. **Zona Fasciculata** (middle): produces glucocorticoids 3. **Zona Reticularis** (Inner): roduces androgen precursors (mostly DHEA with some androstenedione). Each layer produces steroid hormones synthesized from cholesterol. Adrenal **medulla** produces the catecholamines, epinephrine, and norepinephrine.

Answer 21

**Hypothalamic-Pituitary-Adrenal (HPA) Axis** - is involved in the production of glucocorticoids and adrenal androgens from the zona fasciculata and zona reticularis. In response to circadian rhythms or stressors, paraventricular neurons (PVN) in the hypothalamus make and secrete **corticotropin-releasing hormone** (CRH). CRH binds receptors on the anterior pituitary gland, which leads to the synthesis of ACTH (or corticotrophin) from pre-pro-opiomelanocortin (pre-POMC). Of note, cleavage of POMC also yields other hormones such as alpha-melanocyte-stimulating hormone (MSH). **ACTH from the anterior pituitary** is released into the circulation and engages the melanocortin type 2 receptors (MC2-R) in the zona fasciculata of the adrenal cortex predominantly to induce the synthesis of glucocorticoids. It is a GPCR and has an associated protein (MRAP) produced by the adrenal that appears to function as a chaperone to escort MC2-R to the cell surface to allow engagement by ACTH. Circulating glucocorticoids negatively feedback on the hypothalamus (long loop) and the anterior pituitary (short loop), suppressing the release of CRH and ACTH, respectively. This prevents the continued rise of glucocorticoid levels. ACTH is released from the anterior pituitary in a pulsatile pattern that parallels the fluctuating levels of cortisol. **Both ACTH and cortisol levels rise to a peak in the morning (6:00 AM to 8:00 AM)** and decline throughout the day, reaching their nadir at around midnight.

Answer 22

**Renin-Angiotensin-Aldosterone-System** - The zona glomerulosa produces mineralocorticoids. While pituitary ACTH regulates adrenal glucocorticoid and androgen synthesis, it is not the primary regulator of mineralocorticoid synthesis. The 2 primary regulators of aldosterone are (1) the renin-angiotensin-aldosterone system (RAAS) and (2) potassium levels. The kidney releases renin in response to decreased renal perfusion sensed by the juxtaglomerular apparatus. Renin converts angiotensinogen to angiotensin I (AT-I), which is then converted to angiotensin II (AT-II) via angiotensin-converting enzyme (ACE) in the lung. **AT-II stimulates aldosterone synthesis in the zona glomerulosa by activating aldosterone synthase**.

Answer 23

**Mineralocorticoids** The mineralocorticoids, which include: 1. **corticosterone**, 2. **11-deoxycorticosterone**, and 3. **aldosterone**, act on the kidney to increase sodium reabsorption and potassium excretion. Water reabsorption follows increased sodium reabsorption, resulting in an increase in effective circulating volume and therefore increased blood pressure. Specifically, mineralocorticoids achieve this via **increased synthesis of epithelial sodium channels (ENaC) and sodium-potassium ATPases** on the principal cells of the distal nephron. Mineralocorticoids also promote potassium ion secretion at the principal cells because of the gradients produced by the above channels. In high potassium states, aldosterone synthesis is increased to promote potassium excretion. Lastly, mineralocorticoids promote hydrogen ion secretion at the intercalated cells. Interestingly, 11-deoxycorticosterone and corticosterone also have mineralocorticoid effects. These are weaker than aldosterone but can produce a strong mineralocorticoid effect when present in excess levels, as in some forms of congenital adrenal hyperplasia (CAH), for example, 11-beta-hydroxylase deficiency resulting in hypertension.

Answer 24

Cortisol is the major glucocorticoid and increases in response to stress which activates the HPA axis. Therefore, all of its functions can be thought of as allowing the body to function with increased stress. Upon engaging glucocorticoid receptors, cortisol increases the expression of genes that will regulate metabolism, the immune system, cardiovascular function, growth, and reproduction. Cortisol is essential for maintaining blood pressure because it increases the sensitivity of vascular smooth muscle to vasoconstrictors like catecholamines and suppresses the release of vasodilators like nitrous oxide.[1] Cortisol suppresses the immune system, which is the basis for immunosuppressive drug therapy with glucocorticoids. Regarding metabolism, cortisol increases gluconeogenesis and decreases peripheral glucose uptake. These oppose the actions of insulin, and the net effect is an increase in serum glucose. Cortisol also activates lipolysis and stimulates adipocyte growth, which leads to fat deposition. Generally, growth is inhibited, leading to muscle atrophy, increased bone resorption, and thinning of the skin. Of note, glucocorticoids can act on mineralocorticoid receptors. However, aldosterone effects predominate in the kidney because the renal enzyme, 11-beta-hydroxysteroid dehydrogenase-2 (11-beta-HSD-2) converts cortisol to cortisone.[6] The 11-beta-HSD-1 converts cortisone into cortisol. Hence, these enzymes add another layer of regulation to cortisol. Licorice toxicity inhibits 11-beta-HSD-2, causing hypertension and hypokalemic alkalosis with normal aldosterone levels. Also, there can be a loss of function mutations in 11-beta-HSD-2, resulting in hypertension with low aldosterone.

Answer 25

The adrenal androgens, primarily **DHEA**, require **peripheral conversion to active sex steroids** in the gonads and peripheral tissue. Circulating DHEA-sulfate is the best measure of adrenal androgen excess. Some DHEA is also converted to androstenedione. Ultimately, both are converted to **testosterone** in peripheral tissues, which is converted to **5-alpha-dihydrotestosterone** (DHT), the most potent androgen.[2] Adrenal androgens do not play a major role in the adult male because the testes are the major source of testosterone. However, adrenal androgens are important in puberty for both males and females and are the main source of circulating testosterone in females. The rise in adrenal gland androgen synthesis is responsible for adrenarche, which precedes gonadarche.

Answer 26

Adrenal catecholamines, epinephrine, and norepinephrine are involved in executing the fight-or-flight response of the sympathetic nervous system. They increase blood pressure via alpha-1 receptors on vascular smooth muscle. They help increase serum glucose by activating glycogenolysis and increasing glucagon secretion via beta-2 receptors and decreasing insulin secretion via alpha-2 receptors.[

Answer 27

For example, **if Cushing syndrome is suspected**, then evidence of hypercortisolemia is sought. This can be achieved by measurement of evening plasma cortisol and or salivary cortisol, and a 24-hour urine free cortisol. Also useful are plasma ACTH levels to identify the site of the lesion and the cortisol responses to dexamethasone suppression as detailed recently. **If Addison disease (primary adrenal insufficiency) is suspected**, then one can assess the cortisol response to synthetic ACTH (short synacthen test) , and if peak levels are less than 18 ug/dl then the diagnosis is confirmed, and an elevated ACTH is adjunctive evidence. **If primary hyperaldosteronism** is suspected since the patient has hypokalemic alkalosis and hypertension, then the measurement of the plasma aldosterone (PAC) coupled with the aldosterone to renin ratio (ARR) is the most useful screening tests. PAC is generally greater than 15 ng/dl and the ARR greater than 30.[10] **If a pheochromocytoma is suspected**, measurement of plasma or urine metanephrines is the test of choice. In the commonest form of adreno-genital syndrome due to a **deficiency of 21-hydroxylase** resulting in glucocorticoid and mineralocorticoid deficiency and ambiguous genitalia in females and iso-sexual precocity in males, the most useful test is 17-OH-progesterone levels.

Answer 28

Law governing diffusion of gases from high to low concentration gradient Rate of diffusion = dn/dt x D X A X dc/dx where, n = quantity, t = time, d = diffusion D = diffusion coefficient (cm2/second) A = surface area dc = diffusion in partial pressures of gas dx = thickness of barrier

Answer 29

Resistance = 8x Length x Viscosity of Gas ------------------------------------------ pi x radius rest to 4 describes resistance of laminar airflow indicates that resistance increases dramatically as airways narrows (low radius)

Answer 30

**P =2 x Surface Tension / Radius** inside a bubble The law explains that as the radius of a tube or sphere increases, the pressure gradient across the wall decreases. It also states that as the surface tension increases, the pressure gradient across the wall also increases.

Answer 31

Most abundant on nucleated RBCs in bone marrow, helps with Iron deficiency assessment The **sTfR level is elevated in IDA** but is unaffected by inflammation and, therefore, has the potential to better differentiate IDA from Anemia of chronic disease (ACD). Adjunct diagnostic criteria for IDA: - microcytosis with an MCV <80fL, - the sTfR of >55.0nmol/L and - sTfR-ferritin index of>1.4.

Answer 32

**Hepcidin is an iron-regulating peptide hormone** made in the liver. It controls the delivery of iron to blood plasma from intestinal cells absorbing iron, from erythrocyte-recycling macrophages, and from iron-storing hepatocytes. During conditions in which the **hepcidin level is abnormally high**, such as inflammation, serum iron falls due to iron trapping within macrophages and liver cells and decreased gut iron absorption. This typically leads to anemia due to an inadequate amount of serum iron being available for developing red blood cells. **When the hepcidin level is abnormally low** such as in hemochromatosis, **iron overload occurs** due to increased ferroportin mediated iron efflux from storage and increased gut iron absorption.

Answer 33

The **median arcuate ligament** is a ligament formed at the **base of the diaphragm** where the left and right diaphragmatic crura join near the 12th thoracic vertebra. This fibrous arch forms the anterior aspect of the aortic hiatus, through which the **aorta, thoracic duct, and azygos vein** pass. The median arcuate ligament usually comes into contact with the aorta above the branch point of the celiac artery. However, in up to one quarter of normal individuals, the median arcuate ligament passes in front of the celiac artery, compressing the celiac artery and nearby structures such as the celiac ganglia. In some of these individuals, this compression is pathologic and leads to the **median arcuate ligament syndrome**

Answer 34

TeZ BuMaC **Temporal branch**: contract the forehead and elevate eye brow **Zygomatic branch**: open and shut eyes **Buccal branch**: smiling **Mandibular branch**: frowning **Cervical branch**: contract the platysma muscle

Answer 35

Peripheral vasodilation Increased CO & Heart rate Increase circulatory volume Increased MV/ tidal volume Increased O2 consumption

Answer 36

**Inverse Square Law:** The most common relationship between magnetic force and distance is the inverse square law. This means if you double the distance, the force weakens to one-quarter (1/2 squared). If you triple the distance, the force becomes one-ninth (1/3 squared), and so on.

Answer 37

CPP = MAP - ICP Normal ICP, 5-15 mmHg ICP correlates with CVP Cerebral blood flow autoregulation is lost below CPP of 40 mmHg

Answer 38

**Paired Branches**: 1. Inferior Phrenic Arteries: Supply the diaphragm. 2. Middle Adrenal Arteries: Supply the adrenal glands. 3. Renal Arteries: Supply the kidneys. 4. Gonadal Arteries: Supply the ovaries in females (ovarian arteries) and testes in males (testicular arteries). 5. Lumbar Arteries: Supply the muscles and spinal cord in the lumbar region. **Unpaired Branches**: 1. Celiac Artery: divides into the common hepatic artery, splenic artery, and left gastric artery, supplying the stomach, liver, spleen, and pancreas. 2. Superior Mesenteric Artery: Supplies the small intestine, pancreas, and parts of the large intestine. 3. Inferior Mesenteric Artery: Supplies the remaining parts of the large intestine. 4. Median Sacral Artery: Supplies the sacrum and coccyx. **Terminal Branches**: Common Iliac Arteries: Each common iliac artery then divides into the internal and external iliac arteries. The internal iliac artery supplies the pelvic organs and perineum, while the external iliac artery continues into the lower limb as the femoral artery.

Answer 39

**Segment 1 (Caudate Lobe)**: Located posteriorly, between the fissure for the ligamentum venosum and the inferior vena cava (IVC). **Left Lobe**: Further divided into medial (S4) and lateral segments (S2 and S3). Segment 2: Left lateral superior. Segment 3: Left lateral inferior. Segment 4: Medial segment, further divided into superior (4a) and inferior (4b) parts. **Right Lobe**: Divided into anterior (S5 and S8) and posterior segments (S6 and S7). Segment 5: Right anteroinferior. Segment 6: Right posteroinferior. Segment 7: Right posterosuperior. Segment 8: Right anterosuperior.

Answer 40

Each change triggers another which cycles and can go on forever if no limiting mechanism. 1. Fetus pressure on cervix send feed back signals to brain = 2. Oxytocin is released from hypothalamus = 3. Oxytocin increases forces of uterine contractions = 3. This exerts more pressure on cervix = 4. More oxytocin is releases increasing further uterine contractions. This goes on until baby is delivered and pressure on cervix is released.

Answer 41

Indicates amount of free H ions in a solution. Water has 10(-7) mole/Lit of free H ions and represent neutral solution. More H than this makes it acidic and PH drops. Less H than this makes it basic and pH increases. Difference between pH of 6.8 and 8 (range for sustaining life) is only 148 nmols (1.48 x 10(-7) moles/Lit) of H ions.

Answer 42

Conjugate pairs: Acid = H + Base A strong acid completely dissociates in a solution. **Law of mass action**: reactions depends on the concentration if the chemicals involved ie if H is added, more acid is formed. K = [H] [base]/ [acid] Where, K = dissociation constant pK = -log10K 1. **CO2-HCO3 Buffer** - removes H as co2 through lungs by formula: CO2 + H2O = H2CO3 = H + HCO3 Capacity 18 mmols of H/Lit 2. **Hemoglobin buffer**: large capacity - 8 mmols of H /lit CO2 + Hb = HbCOO + H 3. **Phosphate buffer**: Humans secret PO4 in urine which can absorb H secreted in urine. Inside body H is only absorbed by buffers but not removed hence its excretion in urine is important. H2PO4 = HPO4 + H

Answer 43

Expresses the relationship between H and the concentration of the buffer pair. pH = pK + log10[base]/ [acid] **For HCO3/CO2 system**: pH = pK + log10[HCO3]/ [H2CO3] ie pH = pK + log10[HCO3] /[CO2] As most CO2 is converted to H2CO3 Normal ratio of HCO3:CO2 is 20:1 in ECF Hence pH = 6.1 + log10[20/1] = 7.4 Where, HCO3 = 24 mmols and [CO2] = 1.2 mmols/Lit

Answer 44

Hydrogen in urine is buffered by 2 mechanisms: 1. H combines with Na and Phosphate to form NaH2PO4 which is then excreted 2. H combines with ammonia(NH3) synthesised by tubule cells from glutamine - to form ammonium (NH4) which is then excreted. This ensures that pH of ursine doesnot fall below 4.5 and H does not diffuse back to body.

Answer 45

Atom has central nucleus containing protons and neutrons surrounded by cloud of electrons. **Atomic number**: number of protons in atom, example- Carbon has 6 proton and hence its atomic number is 6. **Atomic mass**: total of protons and neutrons together in an atom and is variable, example - Carbon has 6 protons + 6/7/8 neutrons and hence different isotopes with atomic mass 12 for C-12, 13 for C-13 etc **Electrons** are in fixed shells and innermost shell can carry only 2, next shell can contain 8 and third can hold upto 18. These numbers are fixed.

Answer 46

1. **Ionic bonds**: between atoms, they dissolve in water or solution as charged particles, NaCl become Na(cations, +ve) and Cl (anions, -ve) 2. **Covalent bonds**: sharing of electrons between atoms, maximum possible 3 pairs of them, to stabilize themselves. They can be - **single, double or triple** and more stronger. 3. **Stereoisomers**: Stereoisomers of carbon are molecules with the same molecular formula and connectivity but differ in the three-dimensional arrangement of atoms around carbon atoms. The main types are enantiomers (mirror images) and diastereomers (non-mirror stereoisomers, including cis/trans and E/Z forms). They rotate polarised light in either a clockwise (dextro-rotatory) or anticlockwise (Levo-rotatory) 4. **Carbon=Carbon double bonds** Between carbon atoms, atoms can be **cis** ie same side of double bonds or **trans** ie opposite sides of double bond. Some fatty acids, commercial ones are trans type and raise blood cholesterol.

Answer 47

Electrons are shared between atoms but not equally - they ie electrons tend to lean to one atom more, Example 1.- in H2O - shared electrons tends to be closer to Oxygen making them partially negative and away from hydrogen making it partially positive. Thus it has two charge molecules known as **dipoles** and such a bond is **polar covalent** bond. Example 2: non polar bonds has equally shared electrons with no charged atoms, such as methane (CH4)

Answer 48

A weak type of bond Partial positive H+ atom attracts to partial negative atom such as oxygen or nitrogen and forms this bond Can be disrupted easily by heat/acidity example as in ice - easily become water in response to heat

Answer 49

Glycine (non polar aliphatic) Alanine Valine Leucine Isoleucine Tyrosine (non polar aromatic) Phenyl alanine Tryptophan Serine (polar uncharged) Threonine Asparagine Glutamine Aspartic acid (Polar negative charged) Glutamic acid Histidine (Polar +ve charged) Lysine Arginine Cysteine (sulphur containing) Methionine Proline (Imino)

Answer 50

1. **Acetylation**: addition of acetyl (CH3CO) to N-terminal, increases lifespan 2. **Glycosylation**: A. Glycoproteins - addition of carbohydrates to serine/Threonine to OH group known as O-glycosylation via amide group to asparagine (N-glycosylation) or hydroxylysine amino acid side chains, only possible with these. B. Proteoglycans: core protein linked to large chains of carbohydrates 3. Lipid modifications: fatty acids attached to proteins 4. Phosphorylation: Additional of PO4 group by kinases or their removal by phosphatases

Answer 51

1. **Oxio-reductases**: oxidation & reduction reactions, often with Coenzymes as NAD, Ex- dehydrogenase, Oxidase, peroxidase, reductase 2. **Transferases**: Transfer of amino, carboxyl, acyl, carbonyl, methyl, phosphate groups from one molecule to other, Ex- transaminase, transcarboxylase 3. **Hydrolases**: cleave bond between carbon & another atom by inserting water, Ex- esterase, petite, amylase, phosphatase, pepsin, trypsin 4. **Lyases**: breaks carbon-carbon, carbon-sulphur, carbon-nitrogen but not peptide bonds, Ex- decarboxylase, aldolase 5. **Isomerases**: Racemisation of optical or geometric isomers Ex- Epimerase, mutate 6. **Ligases**: formation of bonds between carbon-oxygen, sulphur, nitrogen, etc often hydrolysing ATP to provide required energy Ex- synthetase, carboxylate

Answer 52

Exists in 4 forms, all freely convertible in water, 1. Straight chain: aldehyde at C1, <1% 2. Alfa-D-Glucose, a pyramids ring, C1 attached to C5 through O, 3. Beta-D-Glucose, alfa beta are anomers and has H-OH attachment differences to C 4. D-Glucofuranose: C1 attached to C4

Answer 53

**Mannose**: an Aldose ie aldehyde side chain, tends to form pyranose rings ie 5 carbon with Oxygen, only difference with glucose, H-OH bind at C2 is reverse **Galactose**: also an aldose, tends to form pyranose rings, different from glucose by only H-OH bond at C4 reverse **Fructose**: a ketose, forms both furanose & pyranose rings

Answer 54

**D-Ribose**: H-OH at C2 and **Deoxyribose** l: H-H at C2

Answer 55

**Glucosamine** - amino groups replacing OH group in glucose at C2 **Galactosamine** - amino group replacing OH groups at C2 in galactose

Answer 56

**Sucrose**: alfa-Glucose + b-Fructose **Lactose**: b-Galactose + b-Glucose **Maltose**: alfa-Glucose A + b-Glucose **Isomaltose**: alfa-Glucose + b-Glucose

Answer 57

**Starches:** polymers of glucose, such as - amylose, amylopectins **non-Starches**: **Cellulose**: unbranches polymers of glucose with beta 1-4 linkage **Glycogen**: large glucose polymer Branching at every 10th glucose molecule (instead 13th as in amylopectin)

Answer 58

Chains of carbon and hydrogen like CH2-CH2-CH2 with CH3 group at one end and COOH at other end. They can be: **Saturated** - all carbon single bonded **Mono-Un-Saturated** - one carbon has double bond **Polyunsaturated** - more than one carbon has double bond They all have one end CH3 and other end COOH

Answer 59

Cis means next carbon is present on same side of double C=C bond Trans means next carbon atom is present on other side of C=C double bond Trans means

Answer 60

**Palmitic acid** also named as 1. CH3(CH2)14 COOH 2. n-hexa-decanoic acid 3. C16:O means has 16 carbon & no double bonds Another example: **Arachidonic acid** 1. Cis-5,8,11,14-eicosatetranoic acid 2. C20:4 w-6 (indicates position of first C=C double bond)

Answer 61

1. Prostaglandins 2. Thromboxanes/Prostanoids 3. Leucotriens **Arachidonic acid** (Eicosa-tetra-enoic acid) is one of the FA incorporated into membrane phospholipids by enzyme **Phospholipase A2** **Eicosa-pentanoic acid** is another FA which has 3 double bonds and one of bond is at C17 which is 3 carbon away from omega carbon hence the name omega-3 FA

Answer 62

1. Sugar is ribose or deoxyribose (pentoses) 2. Phosphate: PO4 3. Bases are Purine or Pyrimidines **Purines**: contains 2 rings & are Adenine and Guanine **Pyrimidines** are single rings and are Cytosine, Thymine, Uracil

Answer 63

Nucleosides are nucleotides without phosphate group ie has only ribose and base, example - ATP AMP breaks down & releases 7.3 kcal/mol but can be upto 50 kj/12kcal. 1 glucose molecule generates 36-38 ATP ie energy transfer of 1130 KJ, 270 kcal/mol. This energy is used for other cellular processes.

Answer 64

These are like lysosomes - large complexes of proteins arranged in 4 rings around a central core. Proteins to be degraded are labelled with multiple copies of protein called **Ubiquitin**. Only proteins labelled with ubiquitin are forwarded to central core where they are degraded into smaller peptides.

Answer 65

Microtubule associated protein (MAP) Normally present Accumulation leads to formation of **neurofibrillary tangles** present in Alzheimer’s disease and hallmark cause.

Answer 66

These are 1. Micro filaments, smallest, 7 nm, made of actin 2. Intermediate Filaments, 10 nm Forms rope like structures 3. Microtubules - has tubulin fibres made of alternate alfa and beta tubulins

Answer 67

**The short version** Hyperchloremic acidosis happens because adding chloride forces the body to give up bicarbonate, lowering the strong base in plasma and shifting pH toward acidity. **The Core Mechanism: Electrically Neutral Plasma** Plasma must remain electroneutral: [Na+] + [K+] +… = [Cl-] + [HCO3-] + … When chloride rises, the body compensates by lowering bicarbonate to maintain this balance. Less bicarbonate → less buffering capacity → metabolic acidosis. This is the classical “anion exchange” explanation. --- The Deeper, More Modern Explanation: *Stewart’s Strong Ion Theory* pH is determined by three independent variables: • Strong ion difference (SID) • Total weak acids • PCO2 *For plasma:* {SID} = [{Na}^+] - [{Cl}^-] A normal SID is around 38–42. **What hyperchloremia does** When chloride rises disproportionately: {SID decreases} A lower SID means the plasma has more strong anions relative to strong cations, which forces water to dissociate in a way that increases ([{H}^+]). This is a physicochemical inevitability, not a compensatory process. So in Stewart terms: • ↓ SID → ↑ H\(^+\) → acidosis This explanation doesn’t rely on bicarbonate as a causal agent; instead, bicarbonate falls because pH changes. --- **Why saline (0.9% NaCl) is the classic culprit** Normal saline has: • Na⁺ = 154 • Cl⁻ = 154 This gives an SID of 0, far below plasma’s ~40. Infusing it drags the plasma SID downward, producing hyperchloremic metabolic acidosis. This is why balanced crystalloids (e.g., lactated Ringer’s, Plasma‑Lyte) are preferred in many clinical settings.

Answer 68

MIBG scanning is most useful for tumors that originate from chromaffin or sympathetic nervous system cells, including: **Most common uses** • Neuroblastoma (especially in children) • Pheochromocytoma • Paraganglioma • Medullary thyroid carcinoma • Carcinoid / other neuroendocrine tumors Cleveland Cl... **Additional uses:** • Cardiac sympathetic imaging (heart failure, cardiomyopathy) • Differentiating Parkinson’s disease from similar disorders (because Parkinson’s damages cardiac sympathetic nerves) scienceinsig...

Basic Sciences Stuff Flashcards

(145 cards)