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Jack Westin Bio Flashcards

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1
Q

what type of bond in peptide bond?

A

amide - between carboxyl and amino group

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2
Q

what level of protein structure are disulfide bonds found?

A

tertiary

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3
Q

what level of protein structure are hydrogen bonds found?

A

all except primary

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4
Q

are ester bonds present in proteins?

A

no

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5
Q

DNA point mutation - does not result in wobble codon, leads to the D159E mutation. Which protein structure most affected?

A

amino acid substitution – affects primary structure

aspartic acid to glutamic acid - no big difference in charge so not affecting other structures dramatically

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6
Q

what is the reason behind beta pleated sheets’ zig zag shape?

A

planar geometry of c-c and C-N bonds

planar due to resonance

h bonds do not occur between r groups

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7
Q

what kind of intermolecular interaction aids in the formation of alpha helices?

A

h bonding - between slightly negative oxygen atoms and slightly positive hydrogen atoms of the backbone of the peptide chain

no hydrophobic interactions – outward protrusion of r groups

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8
Q

primary structures are held together by ___ bonds.

A

Amide

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9
Q

Secondary structures are held together by __bonds.

A

h bondings

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10
Q

tertiary structures are held together by what three forces

A

disulfide bonds
hydrophobic effects
ionic effects

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11
Q

only covalent bond that aids in the folding of proteins

A

disulfide bonds - cysteine residues

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12
Q

which AA least likely to be found in alpha helices?

A

proline

contains a ring that makes it rigid and disrupts the formation

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13
Q

chaperone proteins

A

folding

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14
Q

proteinases

A

cleave peptide chain

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15
Q

anhydrases

A

solubilization of molecules

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16
Q

factors responsible for denaturing proteins?

A

pH - charge interactions
temp
reducing agents - disrupt disulfide bridges
solvent type - organic solvents can disrupt folding because usually folded in aqueous solutions leading to hydrophobic residues in the core. organic solvent can flip it inside out

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17
Q

roles of lymphatic system

A

fat absorption
fluid balance
immune surveillance

removal of fluid from tissues, which accumulate due to pressure exerted by capillaries, preventing edema.

immune cells and free antigens which enter the interstitial fluid are carried by lymph through lymph nodes, allowing for antigen presentation and immune surveillance.

large fats are absorbed directly from the intestines to the lymphatic system and are then transported into the bloodstream. Fluid (containing fats, immune cells, and miscellaneous proteins) returns to circulation through subclavian veins, which dump into the vena cava.

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18
Q

where does erythrocyte recycling occur?

A

spleen and liver

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19
Q

where do blood cells origininate

A

bone marrow

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20
Q

erythrocytes

A

rbc

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21
Q

thrombocytes

A

platelet producing

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22
Q

leukocytes

A

wbc

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23
Q

erythrocytes, thrombocytes, leukocytes are derived from the ___ stem cell lineage within the ___.

A

hematopoietic

bone marrow

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24
Q

hematopoietic stem cells differentiate into:

A

common myeloid and lymphoid cells in the bone marrow which differentiate into common blood cells

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25
cells of the lymphoid lineage:
differentiate into lymphocytes (T and B Cells) and natural killer cells
26
myeloid cells differentiate into:
innate immune cells erythrocytes thrombocytes
27
antigens
small molecules or parts of molecules that can be presented by immune cell MHC receptors to immune cells
28
lymphocytes (t or b cells) function
can bind an antigen presenting cell (APC)'s MHC receptor to determine whether the antigen is self or foreign
29
autoimmune disease
immune cells trigger response when lymphocytes bind self antigen and think it is foreign
30
how does the body prevent autoimmunity?
the body eliminates t or b cells that cannot bind MHC receptors or react against self antigens
31
where does positive and negative selection of t cells occur?
thymus
32
positive selection of t cells
tested for the ability to recognize and bind APC MHC receptors - if cannot recognize, eliminated via apoptosis.
33
negative selection of t cells
bound MHC receptor contains a self antigen - t cell tested for ability to not mount immune response - if it does then apoptosis
34
processes of antigen presenting cells (apcs)
dendritic cells and macrophages 1. phagocytose pathogenic organisms 2. digest a pathogen's pp into smaller epitopes 3. display those epitopes on MHC class II surface receptors 4. migrate to lymph nodes to present those antigens to T and B cells 5. secrete proinflammatory cytokines to stimulate the activation of the adaptive immune system
35
enzymatic step of HPT (thyroid) axis?
TSH secreted by the pituitary stimulates rate limiting steps involved in the enzymatic splitting of the thyroid hormones from thyroglobulin
36
hpt axis: hypothalamus recognizes low levels of
t3 and t4
37
molecule important to t3 and t4 production?
iodine - thyroid uses active transport to take up iodine from the blood. precursor amino acid is iodinated forming t3 and t4.
38
two types of cells at thryoid gland: follicular and parafollicular
thyroid gland made of follicles filled with a core of thyroglobulin containing colloid rim of each follicle has follicular cells - secrete t3 and t4 in between follicles = parafollicular cells - secrete calcitonin
39
leptin
appetite-inhibiting secreted from white adipose tissue -- concentration is proportional to body fat level. feeding increases leptin levels obese = leptin resistance
40
ghrelin
appetite stimulating secreted from stomach stimulation of GH release in fasting conditions or in individuals with low body mass, increased desire to consume food = ghrelin secretion increased
41
peptide hormone description
large polar
42
steroid hormone description
small nonpolar, can cross plasma membrane by diffusion
43
receptors for steroid hormones and their domains
inside the cytoplasm or nucleus of target cells after steroid binds, hormone-receptor complex can function as a DNA transcription factor and stimulate or inhibit gene expression domains (1) DNA binding domain (bind specific DNA sequences) (2) nuclear localization domain (3) ligand binding domain specific for steroid (4) some have dimerization domain to make fully active transcription factor (two receptors together to make capable of binding DNA)
44
what is the hormone opposite of calcitonin?
parathyroid hormone
45
how does parathyroid hormone increase blood calcium levels?
action through bone, kidney, and digestive tract bone: increase calcium reabsorption, release of calcium into plasma kidney: decrease phosphate reabsorption and increase calcium reabsorption... increase urinary excretion of phosphate and decrease excretion of calcium... increase calcium reabsorption at intenstine
46
kidney: opposite reabsorption vs. calcium
phosphate
47
acetyl-coA synthesized in the mitochondria must be converted to ____ before shuttled in the cytosol and converted back to acetyl coA by ___.
citrate ATP citrate lysase
48
acetate can be converted to acetyl coA by the cytosolic enzyme___
acyl-coA synthetase short chain family member 2
49
fatty acid synthesis
occurs in the cytosol, conversion of acetyl co A to fatty acids decrease in fatty acid synthase activity would increase acetyl coA levels
50
pyruvate dehydrogenase
produces acetyl coA from pyruvate
51
pyruvate carboxylase
enzyme that converts pyruvate to oxaloacetate, which combines with acetyl coA to form citrate. citrate shuttled to the cytosol where it is broken down into acetyl coA.
52
citrate synthase
step 1 of the TCA cycle is condensation reaction catalyzed by citrate synthase. two carbon acetyl group of acetyl coA is condense with a four carbon oxaloacetate to form 6 carbon citrate. coA is lost as a byproduct
53
in addition to acetyl coA, which of the following is required for fatty acid synthesis?
NADPH ATP anabolic - requires energy and reducing power
54
where does lipogenesis (fatty acid synthesis) take place?
cytoplasm
55
increased activity of actyl coA synthetase ___ kreb's cycle flux
acetyl coA synthetase converts acetate to acetyl coA in the cytosol. decreases - increased transport of acetyl co A out of the mitochondria
56
increased activity of actyl coA synthetase ___ lipid synthesis flux
makes precursor for fatty acid synthesis.
57
promotion of gene expression from histones
need to make the genes more accessible to RNA polymerases.... dna interacts with histones due to the attraction between negatively charged backbone and positively charged residues on histones.... lysine groups on histones can be enzymatically acetylated by histone acetyltransferase enzymes to decrease their positive charge.
58
dna interacts with histones due to the attraction between ___ charged backbone and ___ charged residues on histones..
negative positive
59
why AA residue is acetylated on histones to promote gene expression?
positively charged lysine
60
beta oxidation
process by which fatty acids are oxidized into acetyl coA for entry into the TCA cycle to produce ATP. heightened during times of fasting when glucose is depleted there would also be increased gluconeogensis as well as lipolysis to make fatty acids available for beta oxidation during fasting
61
what is the earliest stage of mitosis that spindle fibers attached to kinetochores could be observed?
metaphase
62
osteoclasts
specialized macrophage that break down the mineralized bone matrix
63
osteoblasts
deposit bone's extracellular matrix and regulate the differentiation of osteoclasts.
64
the neural plate is induced to fold into the neural tube in respond to morphogenic signals secreted by a structure from which germ layer?
mesoderm notochord forms from mesoderm cells soon after gastrulation is complete > signals from notochord cause inward folding of ectoderm at the neural plate > ends of neural plate fuse and disconnect to form an autonomous neural tube neural plate folds into the neural tube which forms the NS. induced by the secretion of morphogens from the notochord, a mesodermal structure that is present during development.
65
signal sequence
peptide sequences located at the n terminus of a protein that directs it towards the secretory pathway, which may lead to export from the cell. receptor proteins are often sent through this pathway to reach the plasma membrane.
66
products of beta oxidation
acetyl coA NADH FADH2 used to generate ATP in the ETC
67
NADPH is produced primarily by the ___
pentose phosphate pathway
68
control of skeletal muscle contraction via Ca2+?
somatic NS signals for Ca2+ release from the sarcoplasmic reticulum into the sarcoplasm
69
which of the following factors would contribute to a decrease in blood pH? I. decreased bicarbonate levels II. increased H+ secretion at the kidney II. decreased respiratory rate
I. decreased bicarbonate levels II. decreased respiratory rate CO2 + H2O <> H2CO3 <> H + + HCO3- increases in blood acidity occur due to an increase in H+ ions shift the buffer to the left. increase in CO2 levels shift right (decreased respiratory rate) or decreases in blood HCO3-) II. = no because increased H+ secretion would reduce total blood H+, thus increasing pH.
70
bicarbonate buffer system
prevents drastic shifts in blood pH CO2 + H2O <> H2CO3 <> H + + HCO3- increases in blood acidity occur due to an increase in H+ ions shift the buffer to the left. increase in CO2 levels shift right (decreased respiratory rate) or decreases in blood HCO3-).

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