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Unit 1 > Unit I Deck 5 > Flashcards

Unit I Deck 5 Flashcards

1
Q

Name three effects of signal transduction in a cell.

A
  1. Regulation of a metabolic pathway
  2. Regulation of gene expression
  3. Changes in cytoskeleton
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2
Q

Why is signal amplification important?

A

Fewer receptors are needed to produce a response.
Time needed to produce response is shorter
2nd messengers can spread throughout the cell, and perhaps to neighboring cells through gap junctions

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3
Q

Rapid changes in signal strength require a __1__ half life signal.

A

Short - that is, fast rate of removal through degradation or clearance.

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4
Q

Steroid hormones generally have what kind of half life?

A

Hours or days (long)

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5
Q

Peptide hormones generally have what kind of half life?

A

Seconds or minutes (short)

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6
Q

How might a cell adapt to prolonged high hormone levels?

A

Adaptation many involve down regulation by desensitization, either by decreased # of receptors, or decreased affinity for the ligand, or decreased sensitivity of the second messenger pathway.

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7
Q

What is the threshold effect in signal transduction?

A

Little or no response to a signal is seen until a certain ligand concentration is reached (a small change in concentration at that point is almost like an all or none response)

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8
Q

What 3 types of cellular signals involve short distances?

A
  1. Autocrine - acting on self
  2. Paracrine - acting locally
  3. synaptic - from one cell to the next
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9
Q

Very low concentrations of a signal, ie in __1__ signals, require __2__ receptors.

A
  1. Endocrine

2. High affinity

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10
Q

Very high concentrations of a signal, ie in __1__ signals, are needed to overcome very low __2__.

A
  1. neurotransmitters

2. receptors on post-synaptic cells

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11
Q

Small, rapidly diffusing molecules that pass into the cell and alter enzyme activity directly include:

A
  1. NO

2. CO

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12
Q

In the transmission of a signal induced by NO, what is the target for the nerve conduction?

A

Nerve acts on the endothelial cells which line the smooth muscle, and causes dilation in the arteriole walls.

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13
Q

Name 3 kinds of signaling molecules that pass directly through the plasma membrane due to their high hydrophobicity.

A
  1. steroids
  2. retinoids
  3. thyroid hormones
    * *receptor is in nucleus or in the cytosol and they bind and travel to the nucleus**
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14
Q

Name 3 characteristics of the eicosinoid signaling molecules.

A
  1. hydrophobic, derived from phospholipids, prostaglandins etc.
  2. engage in autocrine sugnaling
  3. involved in inflammatory response/blood clotting
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15
Q

Aspiring inhibits:

A

cycloogenase, an eicosinoid

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16
Q

Insulin, erythropoietin, glucagon and oxytocin, are examples of:

A

Peptide signaling molecules

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17
Q

Acetylcholine, histamine, serotonin, and glutamate are examples of:

A

“small hydrophilic signaling molecules”

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18
Q

What are “primary response” genes?

A

Genes activated by a hormone-occupied receptor

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19
Q

Hydrophilic signals act through for distinct mechanisms:

A
  1. Trimeric G-protein-coupled receptors
  2. Ligand-gated ion channels
  3. Enzyme-linked receptors
  4. Catalytic receptors
    * *Each typically involves an ensuing second messenger cascade.
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20
Q

Ligand-gated channels are common in ____

A

synaptic signaling pathways

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21
Q

The most common enzyme-linked receptors are those that stimulate membrane-associated:

A

Tyrosine-specific protein kinases, ie the Src kinase.

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22
Q

What is the difference between enzymatic receptors and catalytic receptors?

A

Enzymatic receptors do not have enzymatic activity, while catalytic receptors have cytoplasmic domains that function as enzymes (when an extracellular ligand is bound).

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23
Q

Name 4 types of catalytic receptors.

A
  1. Serine/threonine kinases
  2. Tyrosine kinases
  3. Phosphatases
  4. Guanylate cyclases
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24
Q

Cell signaling involves what kind of binding?

A

Non-covalent

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25
Q

If a patient has 20/40, what does this mean?

A

The patient sees at 20 ft what a normal person sees at 40 ft

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26
Q

What kind of hearing is conductive phase?

A

External ear through the middle ear

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27
Q

What kind of hearing is sensorineural phase?

A

The cochlea and cochlear nerve

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28
Q

In the Weber test, sound vibration lateralizes:

A

toward the impaired ear in **conductive hearing loss

away from the impaired ear **in sensorineural hearing loss (cochlear damage)

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29
Q

In the Rinne test, what would you find in someone with conductive hearing loss?

A

AC = or < BC

30
Q

In the Rinne test, what would you find in someone with sensorineural hearing loss?

A

AC > BC

31
Q

Name some diseases in which molecular diagnosis techniques are commonly used:

A 
Hep C
HIV
Cytomegalovirus
Enteroviruses
Herpes simplex
Chlamydia
C. Gonorrhoeae
(Most by PCR)
32
Q

True or False: Normal flora may be differentiated from pathogenic bacteria based on Gram stain results.

A

False!

33
Q

What bacterial shape is Listeria monocytogenes?

A

GPR

34
Q

What two kinds of bacteria could be responsible for impetigo?

A

Staph aureus, Strep pyogenes (Strep A)

35
Q

IgM is consistent with

A

Current or very recent infection, appears in serum in 1-2 weeks, lasts for 2-3 months

36
Q

Why use molecular testing to diagnose an infectious disease?

A
  1. Good for difficult to culture viruses
  2. Good for highly infectious agents that are dangerous to culture
  3. Good for detecting carrier/colonization (MRSA)
  4. Good for determining how much virus is in the blood
  5. More sensitivity over current methods (though false positives and false negatives both occur)
  6. Fast
37
Q

What is the film array pouch?

A

Developed by the army, fast and easy detection of a ton of respiratory viruses and bacteria and yeast, nested, multiplex PCR, good for live and dead organisms, BUT not that sensitive, risk of false positives or contamination

38
Q

True or False: Homologous recombination is carried out by the same enzymes as in DNA repair.

A

True

39
Q

What are the three components for Haldane’s Rule to apply?

A

The disease must be X-linked, recessive

The disease must show reduced fitness (f mutations

40
Q

Name the enzyme that attaches carbohydrates to Asn residues in proteins.

A

Oligosaccharyltransferase

41
Q

ABO blood group antigens are oligosaccharide components of glycoproteins and:

A

Glycolipids

42
Q

What is the glycoprotein component of mucus?

A

Mucins

43
Q

Endoglycosidases remove _____ from glycoproteins

A

Carbohydrates

44
Q

The O blood group is _____ compared with the A and B alleles.

A

Recessive

45
Q

What are disease caused by defects in proteoglycan degredation?

A

Mucoploysaccharidoses

46
Q

Individuals with blood type AB have blood group alleles that are:

A

Codominant

47
Q

A linear or branched polymer of sugars is a _____.

A

Polysaccharide

48
Q

Cys residues in mucins allow them to:

A

Polymerize

49
Q

What is encoded by the ABO gene locus?

A

Gycosyltransferases

50
Q

What is the MOI for Hemophilia A?

A

X-linked recessive

51
Q

What is the MOI for DMD?

A

X-linked recessive

52
Q

Read over the characteristics for multifactorial inheritance.

A
  1. Although the disorder is obviously familial, there is
    no distinctive pattern of inheritance within a single family.
  2. The risk to first-degree relatives, determined from family studies, is approximately the square root of the population risk.
  3. The risk is sharply lower for second-degree than for first-degree relatives, but it declines less rapidly for more remote relatives.
  4. The recurrence risk is higher when more than one family member is affected.
  5. The more severe the malformation, the greater the recurrence risk.
  6. If a multifactorial trait is more frequent in one sex than in the other, the risk is higher for relatives of patients of the less susceptible sex.
  7. If the concordance rate in DZ twins is less than half the rate in MZ twins, the trait cannot be autosomal dominant, and if it is less than a quarter of the MZ rate, it cannot be autosomal recessive.
53
Q

What is pleiotropy?

A

When one gene influences many phenotypic effects, ie phenylketonuria

54
Q

A LOD score of 3 or greater in an autosomal chromosome is evidence of?

A

Gene and polymorphism are linked!

55
Q

A LOD score of -2 or lower is evidence of?

A

No linkage

56
Q

What is the MOI of neurofibromatosis?

A

Autosomal dominant

57
Q

True or False: If two loci are within 50cM of each other, they must be on the same chromosome.

A

True

58
Q

True or False: Most intragenic markers have insignificant recombination rates with the rest of the gene.

A

True, except for DMD

59
Q

If the recombination distance between a disease and a marker is 15 cM, it the physical distance closer to 10 megabases or closer to 20 megabases?

A

Closer to 20. With things further apart, the instance of double crossovers increases, therefore the cM underestimates the actual distance.

60
Q

What is the analogy for a linked extragenic marker?

A

String on a suitcase. Easy to lose

61
Q

What is the analogy for an intragenic marker?

A

Label is on suitcase, very unlikely to separate

62
Q

What is the analogy for disease-causing mutations?

A

The bomb inside the suitcase, do not need label to know that.

63
Q

For chromosomal deletions, what is the take home message?

A

Size is NOT as important as which genes, and how many are missing.

64
Q

When do translocations present problems?

A

In reproduction, if unbalanced

65
Q

What kinds of translocations will likely produce problems in offspring?

A

Adjacent 1
Adjacent 2
3:1 (liveborns rare)

66
Q

Robertsonian transloaction only occurs with:

A

Acroentric chromosomes

67
Q

Integrons are ___1___ DNA elements with the ability to capture genes, but they are often housed in transposons, which are ___2___.

A
  1. Nonmobile

2. Mobile

68
Q

What is the difference between insertion sequences and transposons?

A

IS’s ONLY encode for functions involved in insertion events. Transposons code for more, ie, antibiotic resistance.

69
Q

What does ESBL stand for?

A

Extended spectrum beta lactamase - resistant to penicillins, 3rd and 4th generation cephalosporins, and monobactams…use a carbapenem to treat.

70
Q

What are the four major mechanisms of antibiotic resistance?

A
  1. Enzymatic inactivation
  2. Decreased permeability
  3. Efflux
  4. Alteration of the target site
71
Q

What bacteria carry ESBL’s?

A

Klebsielle pneumonia
E. Coli
P. mirabilis

Unit 1 (5 decks)

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