Abby Anderson Flashcards

1
Q

How do the bases of DNA nucleotides pair up, what type of bonding

A

Adenine (purine) pairs with thymine or uracil in RNA (pyrimidines)

Guanine (purine) pairs with cytosine (pyrimadine)

Pair via hydrogen bonds

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2
Q

What is the process of transcription

A
  1. Section of DNA containing gene unzips and unwinds under control of DNA helicase at start codon breaking H bonds
  2. The sense strand 5’-3’ contains code for protein
  3. Free RNA nucleotide bases pair with complementary bases on the antisense strand
  4. RNA polymerase forms phosphodiester bonds between RNA nucleotides
  5. Transcription stops at stop codon forming mRNA
  6. mRNA leaves through nuclear pore to ribosome as DNA helix reforms
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3
Q

What is the process of translation

A
  1. mRNA bonds to small subunit of ribosome at Start codon
  2. Complementary tRNA binds to start codon carrying the corresponding amino acid
  3. Next tRNA binds to next codon (max 2 tRNAs at once)
  4. First amino acid attaches to amino acid on second tRNA by peptide bond catalysed by peptidyl transferase
  5. Ribosome moves along mRNA to stop codon and polypeptide released
  6. May be modified further at golgi
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4
Q

What are autosomal traits

What are X linked traits

A

Genes present on non sex chromosome

A trait which gene is located on the X chromosome, diseases that are x linked usually affect males as they only have one allele of the gene

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5
Q

Explain monogenic inheritance

A

Inheritance of a trait through one gene with autosomal dominant traits being always expressed if present and autosomal recessive traits being expressed only if two copies of the allele are present

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6
Q

Explain polygenic inheritance
Define multi factorial traits

Give examples

A

Characteristics influenced by several genes showing continuous variation such as skin colour

Traits influenced by more than one gene plus environmental factors such as height

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7
Q

Define germ line mutation

Define somatic mutation

A

A mutation passed through gametes to the next generation so every cell in the new organism will carry the mutation

A mutation that occurs in a particular cell and cannot be passed on in reproduction

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8
Q

What is substitution mutation and what are the types of substitution mutation

What is deletion/insertion mutation and what can this lead to

A
When a single base or series of bases is swapped in the DNA code causing:
Silent mutation
Nonsense mutation
Missence conservative
Missense non conservative

Where a base is inserted or deleted into the DNA sequence, this can lead to frameshift mutation if not in multiples of 3

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9
Q

What happens in epigenetics

A

The structure of a base in DNA is modified but not changed to a new base, this can carry extra information which impacts how the code is expressed

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10
Q

What is the brocess of blastocyst formation (3 stages)

When does this occur

A

First week

On day 1: fertilization forming zygote
Day 2-3: diploid germ cell divides to form small bundle of cells called the morula
Day 3-4: morula develops into blastocyst consisting of the blastocyst cavity, inner cell mass and trophoblast (outer cell mass)

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11
Q

What characteristic do the cells of the blastocyst have

A

They are pluripotent- having the ability to develop into all tissue types in response to specific enviromental stimuli but not whole organism

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12
Q

What causes down syndrome

A

Caused by extra chromosome 21 in 95% of cases

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13
Q

When does the bilaminar germ disk develop

What is the process of bilaminar germ disc formation

A

Second week

Day 9: blastocyst develops into bilaminar germ disc as the inner cell mass divides into two layers, the epiblast and the hypoblast, the amniotic cavity develops inside the epiblast

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14
Q

When does gastrulation occur

What happens during gastrulation

A

Third week

The epiblast gives rise to 3 embryo layers under the control of locally acting cytokine growth factors
Mesoderm
Ectoderm
Endoderm

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15
Q

What is the process of gastrulation (3 stages)

A
  1. Cells from epiblast proliferate downwards from primitive streak and migrate laterally to form mesoderm between epiblast and hypoblast
  2. After proliferation epiblasts form ectoderm
  3. Once mesoderm comes into contact with hypoblast cells closest to hypoblast differentiate into cells of the endoderm
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16
Q

When does notocord formation occur

What is the notocord

What is the process of notocord formation

A

Third week

Notocord: rod shaped mesenchymal structure which defines the long axis of the embryo eventually to be replaced by vertebral column

Day 16-17: cells invaginating from primitive streak migrate cranially in midline between epiblast and hypoblast to give mesoderm layer, cells in the midline form the notocord

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17
Q

When does neural crest formation occur?

What is the process of neural crest formation? ( 4 points)

A

Third week

Day 19 onwards:

  • notocord sends signals to endoderm causing neural plate to form and infold forming neural folds and groove
  • this causes changes in crest of neural folds so some of the endoderm cells become neural crest cells
  • neural folds fuse to form neural tube and neural crest cells become a distinct population
  • neural crest cells migrate throughout the body
18
Q

What causes spinal bifida and what does it result in?

A

Incomplete closure of embryonic neural tube

Leading to some vertibrae overlying the spinal cord after not forming fully and remaining unfused and open

19
Q

How do neutrophils reach the infected area

A

Extravasion:

Rolling, integrin activation by chemokine, stable adhesion, migration through epithelium

20
Q

What is the process of phagocytosis

4

A
  1. Microbe binds to receptor on phagocyte
  2. Phagocyte engulfs microbe creating phagosome
  3. Phagosome fuses with lysosome forming phagolysosome
  4. Microbe destroyed by lytic enzymes
21
Q

What substances do NK cells use to destroy infected cells

What cells do NK cells target

A

Perforin and granzyme

Cells that have lost their class 1 MHC molecules

22
Q

What is the compliment pathway

A

Pathway activated by classical pathway (antibody)/ alternative pathway(microbe) / lectin pathway (mannose binding lectin)
C3 splits into C3a (inflammation) and C3b (opsonisation and phagocytosis)
This triggers C5 to split into C5a (inflammation) and C5b
Proteins of complement cascade form MAC causing lysis of microbe

23
Q

What are some innate immune components of the oral mucosa

5

A
Toll like receptors 
SLgA
B defensins 
Mucous coat
Intra epithelial lymphocytes
24
Q

What are some innate immune components of the nasopharynx and tonsils
2

A

SLgA

B cells

25
Q

What are some innate immune components of the tongue

3

A

Microbial antagonism
Von ebner glands
Flora

26
Q

What are some innate immune components of saliva and salivary glands
6

A
SLgA
Lysozyme 
Lactoferin
Peroxidase
Mucins
Agglutinins
27
Q

What are some innate immune components of the tooth and GCF

5

A
Complement proteins 
Enamel pellicle 
IgM, IgG
Peroxidase activity 
Lysozyme
28
Q

What are the features of chronic inflammation

4

A

Tissue destruction and ulceration
Inflammatory infiltrate consisting of macrophages, plasma cells, lymphocytes
New fibrous tissue production
Granulation tissue formation

29
Q

What is histamine released by

What does it bind to

What does it cause

A

Mast cells, basophils, platelets

G protein coupled trans membrane receptors on target cells

Vasodilation, neurotransmitter release, cAMP release, gastric acid secretion, smooth muscle constriction, mucous secretion, increase in endothelial permeability

30
Q

What are the types of histamine
Where are they located
What is each of their functions

A

H1 - smooth muscle and endothelial cells - allergic response

H2 - gastric parietal cells - gastric acid secretion

H3 - central nervous system- neurotransmission

H4- mast cells, eosinophils, T cells, dendritic cells- regulate immune response

31
Q

What is a granuloma

What are some granulomatous diseases
5

A

A collection of activated macrophages which may aggregate to for giant cells such as langerhan cells

Tuberculosis 
Leprosy
Sarcoidosis 
Crohn’s disease 
Oro facial granulomatosis
32
Q

What is tuberculosis

What is the histopathology of TB

A

A chronic granulomatous disease caused by mycobacterium tuberculosis generally affecting lungs

Mycobacterium ingested and engulfed by macrophages, this excites Tcell response but as mycobacterium intra cellular they are protected. Intra cellular mycobacterium in macrophages drive ongoing inflammation causing tissue damage during type 4 hypersensitivity reaction

33
Q

What is the process of rheumatoid arthritis development

4

A

Unknown stimulus leads to chronic inflammation of joints

Fibrous repair occurs in response to tissue damage

Fibrous tissue remodelling and contraction

This creates characteristic deformation and ankylosis of the joints

34
Q

When do the brachial arches first appear

How many brachial arches are there

What are they lined with

A

3rd week

5 pairs (12346)

Lined on outside by epithelium derived from ectoderm
Lined on inside by endoderm derived from endoderm tissue

35
Q

What is the associated nerve of the 1st brachial arch

What are the skeletal elements

What are the muscular elements

What are any other elements

A

Trigeminal nerve 5

Malleus, incus, spine of sphenoid, lingula of mandible, mental ossicles

Muscles of mastication, tensor tympani, tensor veli paltini

Auditory tube, tympanic cavity

36
Q

What is the associated nerve of the 2nd brachial arch

What are the skeletal elements

What are the muscular elements

What are any other elements

A

Facial nerve 7

Stapes, lesser horn of hyoid, upper part of bony hyoid

Muscles of facial expressions, stylohyoid, posterior belly of digastric, buccinator

Palatine tonsils

37
Q

What is the associated nerve of the 3rd brachial arch

What are the skeletal elements

What are the muscular elements

What are any other elements

A

Glossopharyngeal nerve 9

Greater horn of hyoid, lesser body of hyoid

Stylopharyngeus

Inferior parathyroid thymus

38
Q

What is the associated nerve of the 4th brachial arch

What are the skeletal elements

What are the muscular elements

What are any other elements

A

Superior laryngeal branches of vagus 10

Thyroid cartilage, epiglottis

Cricothyroid

Superior parathyroid glands

39
Q

What is the associated nerve of the 6th brachial arch

What are the skeletal elements

What are the muscular elements

What are any other elements

A

Recurrent laryngeal branches of vagus 10

Cricoid, arytenoid cartilage

Intrinsic muscles of larynx

Ultimobrachial body

40
Q

Which brachial arch forms the mandible and maxilla

A

First brachial arch

Grows ventraly and splits to give maxillary process and mandibular process

41
Q

Which brachial arch forms the anterior two thirds of the tonge

Which nerves innervate it

A

First brachial arch

Trigeminal nerve

42
Q

Which brachial arch forms the posterior third of the tongue

What nerve innervates it

A

Third and fourth arches

Glossopharyngeal and vagus nerve