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ISOM > Biochemistry/Biology > Flashcards

Biochemistry/Biology Flashcards

1
Q

AAs

A

memorize structures and names

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2
Q

Henderson-Hasselbalch Equation

A

pH=pKa+log[A-][HA]

Association Constant: [A-][HA]

calculate the ionization of a weak acid or amino acid side chain at a particular pH given the pKa.

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3
Q

amino group pKa

A

9, becomes neutral above 9

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4
Q

carboxylate group pka

A

2, becomes -1 above 2

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5
Q

Isoelectric point

A

PH when there is zero net charge

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6
Q

bicarbonate (HCO3-) buffer

A

CO2+H20 –> (CA enzyme) H2CO3 –> H+ + HCO3-

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7
Q

Phosphate buffer

A

3 ionizible groups, biologically relevant, pKa of 7.2

phosphate in concert with calcium forms hydroxyapatite (bone)

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8
Q

most drug pHs

A

weak acid or weak bases

need to be able to transport across membranes

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9
Q

AA structures 1,2,3,4

A

1: AA sequence
2: alpha helical, Bturn/sheet, mixed a/b, random coil
alpha sheet (H bond between, peptide-bond, carbonyl oxygen and amid (N+4))- rigid formation side chains extend outward
Beta sheet- parallel or anti parallel, H bond between peptide segments
Beta turns:
proline kink
Glycine packing
3:3-D arrangement of AA with linear peptide chain, protein folding patterns
4- multiple subunits

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10
Q

what forms disulfide bond and what do disulfide bonds do?

where do these occur and under what conditions?

A

-2 cysteines

stabilize protein folds with crosslinks

oxidizing conditions in the ER or Golgi facilitate S-S formation

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11
Q

Alzheimer’s Disease

Protein folds

A

Deposits of intracellular tau form neurofibrillary tangles; extracellular aggregates of amyloid-β form amyloid plaques.

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12
Q

Parkinson’s disease

Protein folds

A

Formation of protein inclusion bodies (Lewy bodies) containing α-synuclein and ubiquitin.

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13
Q

Huntington’s Disease

Protein folds

A

CAG (glutamine) repeat number correspond to the severity

Expansion of polyglutamine (pQ) results in intracellular aggregation of proteins.

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14
Q

Amyotrophic Lateral Sclerosis (ALS)

Protein Folds

A

Formation of protein aggregates in motor neurons, associated with mutant superoxide dismutase proteins.

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15
Q

Retinitis pigmentosa

protein golds

A

Accumulation of misfolded mutant rhodopsin inside endoplasmic reticulum of retinal cells

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16
Q

Prion Protein (PrP)

A

causative agent of transmissible spongiform encephalopathies (TSEs), including Creutzfeldt-Jacob disease in humans, scrapie in sheep, and bovine spongiform encephalopathy in cattle.

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17
Q

Hb vs Mb

which one follows allostery

A

Hb-quaternary structure of Hb uses cooperation to bind and unbind oxygen (allostery)
On the other hand Mb is hyperbolics (no cooperativity, follows MM kinetics)

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18
Q

Collagen structure

A

long, rigid, 3 left handed- alpha helices wind forming triple helix

can form gel or strong fiber

rich in Pro and Gly

Small insertions of bulky groups into the alpha helices can dramatically modify the triple helix arrangement. Additional rigidity is created through cross-linking the chain together in a vitamin C dependent process.

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19
Q

Collagen formation

A
  1. Pro and Lys side chains are hydroxylated during biosynthesis
  2. α chains assemble through initial formation of disulfide chains at C-terminus to enable triple helix formation.
  3. Procollagen is secreted into extracellular matrix.
  4. Terminal polypeptides are cleaved in extracellular space to form triple-helical tropocollagen.
  5. Collagen is cross-linked via lysyl oxidase, creating a strong fiber.
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20
Q

Collagen diseases

A

EDS- stretchy skin, unable to process collagen correctly, mutations in AA sequences of 1,3,5

Osteogenesis imperfecta- brittle bones, results from reduced abundance of fibril forming collagen chains or mutations that interfere with helical packing.

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21
Q

Osteogenesis imperfecta types

A

1: early infancy
2: in utero (prevents helix formation by replacing gly with bulky side chain)

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22
Q

Elastin locations

A

Connective tissue protein in lungs, wall of large arteries, and elastic ligaments

degradation of elastin is required for tissue remodeling

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23
Q

Elastin related diseases

A

Marfan syndrome (mutations in fibrillin-1 protein results in impaired structural integrity in skeleton, eye, and cardiovascular system)

Emphysema
Elastase degrades elastin in alveolar walls, and other structural proteins.
α1-antitrypsin (serpin superfamily) is a serine protease inhibitor that protects tissues from proteases released by inflammatory cells (e.g., neutrophil elastase).

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24
Q

how smoking damages elastin

A

Smoking oxidizes methionines in α1-antitrypsin, inactivating this protease inhibitor causing elastase activity and lung damage (cleavage of elastin).

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25
Q

non polar

A

no O or N, oily

more likely to face interior or a protein facing towards the outside of a trans membrane sequence

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26
Q

do polar side chains enhance or decrease water solubility

A

enhance

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27
Q

2 common bio buffers

A

bicarb, phosphate

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28
Q

most fundamental properties of a molecule for drug action is

A

its acid and base properties

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29
Q

aspirin

acidic or basic

A

acidic

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30
Q

pyrimethamine

acidic or basic

A

basic

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31
Q

beta turns involve which AAs

A

proline and glycine

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32
Q

peptide bonds form through what type of rxn

A

condenstion

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33
Q

tissue remodeling

A

requires elastin degredation, mediated by protease elastase

Elastase activity is tightly controlled by alpha1-antitrypsin (a serpin). Smoking oxidizes methionine in alpha1-antrypsin, resulting in activation of elastase and lung damage (major cause of emphysema).

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34
Q

lys involvement in elastin formation

A

Lys side-chains in tropoelastin are oxidatively deaminated to enable cross-linking of the chains to form elastin.

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35
Q

Prion proteins

A

Prion protein adopts infectious structure and represents the first identified infectious disease that only involve protein. Prion protein in the noninfectious state contains largely alpha helices. In contrast, the infectious form contains beta sheet structures.

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36
Q

Histones

and Histone core structure

A

Histones- basic AAs, proteins which interact with negatively charged DNA, DNA wraps around this
Histone core: 145 bp DNA and octamer of histones

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37
Q

Heterochromatin

A

very condensed, usually at centromeric and telomeric regions

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38
Q

Euchromatin

A

less condensed

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39
Q

Nucleosome core particle

A

DNA and octamer of 8 protein subunits

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40
Q

Epigenetic regulation

A
  • control of gene expression by histone modification and modification of DNA bases but NOT the sequences (epigenetic- “on top of DNA modifications”)
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41
Q

subunits of core nucleosome particles

A

H2A with H2B 2 seperate, link with H3H4 tetramer (see pic)

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42
Q

Chromatin structure during Mitosis vs Interphase

A

Mitosis- chromosomes are condenses

Interphase (G1, S, and G2)- chromosomes are decondensed, euchromatin, available for transcription and translation

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43
Q

chromosome nomenclature

A

6p21.34

6-chromosome number
p-short arm
2-region
1-sub region
3-sub-band
4- sub-sub band
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44
Q

histone modification

acetylation on lysine

A

removes a positive charge on histones, may loosen interaction with DNA converted to more assessible

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45
Q

histone modification

methylation occurs on lysine

A

mono, di, or tri, attract heterochromatin specific protein and strength interaction with DNA

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46
Q

histone modification

phosphorylation on serine

A

adds negative charge to serine, reduces interaction from DNA and histones

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47
Q

effect of methylation on DNA

A

methylation of cytosines in CpG turns off the promoter

-more methylation in inactive chromatin

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48
Q

enzymes that control acetylation and methylation on histones

A

– Histone acetyl - transferases (HATs) add acetyl group
– HDACs (histone deacetylase complexes) remove acetyl group
– Histone methyl transferases add methyl group
– Histone demethylases remove methyl group

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49
Q

gene expression

A

Expression of a small fraction of genes depends on their origin: paternal origin or maternal origin.
One of the two alleles (maternal or paternal) is expressed, and the other allele is imprinted (inactive or not expressed).
Imprinted genes are not expressed. Imprinted may be in heterochromatin state

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50
Q

relationship between Prader-Willi syndrome (PWS) and Angelman Syndrome (AS)

A

AS and PWS- deletions in chromosome 15q11-q13

Two different syndromes but same deletion (depends on deletion from mother or father, parent specific inheritance)

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51
Q

Angelman Syndrome (AS)

A 
•	UBE3A
–	E3 ubiquitin ligase
–	Brain specific expression
–	Maternally expressed
•	Mutations in UBE3A gene are seen in AS individuals where maternal chromosome is not deleted
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52
Q

Prader-Willi syndrome (PWS)

A 
•	Genes
–	Multiple genes in the PWS region
•	Approximately 20 paternally expressed genes are missing
–	No mutations characterized
–	Some candidate genes 
•	Necdin (NDN)
•	SNURF-SNRPN
•	snoRNAs
•	Imprinting center
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53
Q

is warfarin dosing dependent on genotype?

A

yes, CYP (cytochrome p450) enzymes involve activation/inactivation of drugs
Warfarin dosing is depending on genotype isoforms of CYP enzymes of patient

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54
Q

history of determining DNA

A 
Mendel- unit factors  genes
Griffith’s experiments- virulent strain vs avirulent strain and mice, helped determine DNA had genes
Bacteriophages inject DNA
Chargaff’s rules- A=T, C=G
Watson and Crick Model
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55
Q

ribose vs deoxyribose

A

sugar w/wo O

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56
Q

Purines

A

AG

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57
Q

Pyrimidines

A

CUT

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58
Q

Nucleotide

A

Nucleoside + phosphate, make up back bone

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59
Q

Nucleotide uses

A 
DNA/RNA constituents, Cofactors, 
energy currency (ATP), 
cell signaling (GTP in G protein couple receptor)

More examples: FAD, NAD (electron carriers), cAMP, cGMP (2nd messengers), CoA (carbon carrier in FA metabolism)

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60
Q

analogs of base, nucleoside, and nucleotide therapeutic agents

A

– Base analog
5-fluorouracil (cancer therapeutic)

– Nucleoside analogs
Ganciclovir: 2’ deoxy guanosine analog (CMV retinitis therapy)
AZT (Zidovudine): 3’-deoxy-3’-azido-thymidine (HIV/AIDS)

– Nucleotide analog
Adefovir (Hepatitis)

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61
Q

distinct structural features, strand orientation and complementarity in DNA

A

Antiparallel strands, B 10 bases/turn, right handed turn= for humans

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62
Q

DNA denaturation kinetics

A

concentration indepenent

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63
Q

DNA renaturation

A

2nd order kinetics, dependent on concentration of strands

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64
Q

distinction between hyperchromicity of single and double stranded DNA and its application for determining base composition

A

Double stranded= S shaped curve because CG bonds are stronger
Single stranded= linear

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65
Q

non watson-crick basepairing

A

Non WC- can stabilize some single stranded conformation, used in gene regulation and telomere stability

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66
Q

I-motifs (intercalated motif)-

A

found in C rish regions of the genome at telomeres and promoters, they are formed between protonated C and neutral C in a single strand of a double stranded DNS
I motifs help visualize structures, vary with cell cycle phases

67
Q

Effects of alkylating agents such as cyclophosamide, nirosourea and cisplatin on DNA structure and their utility for therapy

A

DNA = damaged by alkylation

cyclophosamide, nirosourea and cisplatin, chemo drugs that cause cell death

68
Q

start codon

A

AUG (met)

69
Q

stop codon

A

UAG, UGA, UAA

70
Q

Protein vs enzyme

A

Enzymes are a group of proteins that catalyze chemical transformations

Proteins can be involved in:
catalysis/chemical transformation- phosphofructokinase, polymerases
Extracellular signaling (insulin, glucagon, anfiotensin)
Cell structure (actin, tublin)
Transport (hemoglobin, albumin)
Energy transduction (ion transport, muscle contraction)
Immunity (antibodies)

71
Q

Oxidoreductases

A

catalyze oxidation/reduction reactions that typically involve electron transfer involving NAD(P)+/NAD(P)H or FAD/FADH2
• NADH is electron donor, pyruvate is electron acceptor
• NAD(P)+ + 2e-  NAD(P)H
(Mobile Electron Carrier)
• FAD/FMN is a 2 e- oxidizing agent, which becomes reduced to FADH2/FMNH2
These rxns are important in cytochrome P450 (CYP) in oxidative metabolism

72
Q

Transferases

A

catalyze transfer of C-, N-, or P-containing groups
•Ex aspartate amino transferase
•Hexokinase

73
Q

Hydrolases

A

catalyze cleavage of bonds by addition of water

• Ribonuclease (RNase), Phosphodiesterase

74
Q

Lyases

A

catalyze cleavage of carbon-carbon, carbon-sulfur, and carbon-nitrogen bonds

75
Q

Isomerases

A

catalyze racemization of optical or geometric isomers (no net change in bonding)

76
Q

Ligases

A

catalyze the formation of bonds between carbon and oxygen, sulfur, or nitrogen coupled with input of energy (typically involving ATP).

77
Q

functional significance of a zymogen (proenzyme) in terms of the need to deliver proteases to proper compartment (extracellular matrix or plasma) prior to enzyme activation.

A

Zymogens are inactive and they prevent enzyme action in unwanted locations
Protease activation occurs after extracellular transport

78
Q

apoenzyme

active or inacive

A

inactive

79
Q

Holoenzyme

A

apoenzyme + cofactor

80
Q

isoenzymes

A

represent important biomarkers for dx
Ex: level of CK type in different tissues
Skeletal M, cardiac MB, brain B
Elevated CK can diagnose MI, skeletal muscle diseases (muscular dystrophy)

81
Q

to describe the different roles of the protein side chains within an enzyme active site in terms of binding and catalysis, and relationships to pH optimum.

A

Active site: substrate binds to enzyme active site where substrate is chemically transformed into product

Binding interactions: temporary bonds form with substrate in binding site

Catalysis involves distinct side chains: catalytic side chains medicate chemistry

82
Q

post-translational protein modifications (PTMs)

A

Protein phosphorylation (Tyr, Ser, Thr); global regulation of cell function
Glycosylation of extracellular proteins permit self-recognition
Ubiquitination and SUMOylation and respective involvement in protein degradation or protein localization and binding interactions
Oxidation/Reduction and role of disulfide bond formation in the stabilization of protein structure)
Acetylation and regulation of DNA packaging in histone complexes to regulate transcription (formation of mRNA)
Lipidation and membrane targeting
Methylation and mediation of protein recognition or modulation of other PTMs.

83
Q

Thiamin Pyrophoasphate (TPP) as a cofactor

A

co factor of oxidative decaboxylase

ex pyruvate to acetyl CoA

84
Q

FAD/FADH2 as a cofactor

A

oxidation/reducation, serves in electron storage, often couples with NAD+

85
Q

NAD(P)+/NAD(P)H as a cofactor

A

redox rxn, mobile electron carrier

86
Q

CoA-SH as a cofactor

A

acyl group transfer

87
Q

Pyridoxal Phosphate (PLP) as a cofactor

A

catalyzes transamination, deamination, and decarboxylation reations

involved in AA metabolism

88
Q

Biotin as a cofactor

A 
carboxylation reactions (Carries Activated CO2) 
Pyruvate to oxaloacetate
89
Q

tetrahydrofolate

A

transfer one carbon fragments

methylation of homocysteine to form methionine

90
Q

Semiconservative

A

1 old and 1 new strand when replicated

91
Q

Okazaki fragments

A

on lagging strand
bacterial okazaki fragments- 1.0 to 2.0 Kb
Human o frag- 0.1 to 0.2 Kb

92
Q

Proof reading

A

DNA polymerase can edit and proofread to reduce error rate

93
Q

Helicase

A

unwinds to strands

94
Q

Primase

A

in bacteria synthesizes RNA primers

95
Q

Polymerase a

A

in humans synthesizes RNA primers

96
Q

DNA polymerase III (replicase)

A

in bacteria adds new nucleotides to the 3’

97
Q

Polyemerase e and d

A

adds new nucleotides to the 3’

in humans

98
Q

DNA polyermase I

A

in bacteria- removes primers

99
Q

RNaseH

A

removes primers in humans (mutations in this cause neuro- inflammatory disorders and in systemic lupus)

100
Q

DNA ligase

A

joins fragments

101
Q

Type II topoisomerase (Gyrase in E coli)-

A

relieves unwinding, cuts both strands and allows DNA to rotate, heterotetromer (A2B2)
Type 1- makes nicks on 1 strand
Type II (bacterial DNA gyrase)- makes 2 guts

102
Q

DNA polymerase bacteria

A

Bacteria (multisubunit)
Polymerase Activities

Pol I 5’-3’ polymerization
5’-3’ exonuclease
3’-5’ exonuclease

Pol II 5’-3’ polymerization
3’-5’ exonuclease

Pol III (replicase)	5’-3’ polymerization
		3’-5’ exonuclease

Bacterial initiation protein
1 origin of insertion

103
Q

Human polymerase bacteria

A 
Human (multisubunits)- editing and proof reding
Polymerase a (primase)
Polymerase b (repair)
Polymerase g (mitochondrial replication)
Polymerase d (nuclear replication)
Polymerase e (nuclear replication)

Thousands of origins of replication

104
Q

gyrase

A

Point mutations in gyrase lead to antibiotic resistance:
N-terminal end of GyrA (most mutations).
C-terminal end of GyrB (few mutations).

105
Q

Replication inhibition in cancers

A

Mammalian Topo I is the target enzyme for anticancer drugs
Topoisomerase I makes a cut on one strand of the DNA and binds to 3’ end of the phosphodiester back bone
After it relieves the supercoiling, DNA is religated
Topotecan (Hycamtin) is FDA approved for ovarian cancer and small cell lung cancer
Topotecan stabilizes Topo I-DNA complex and prevents the religation step (inhibition of replication)

106
Q

End replication problem

A

E. coli has circular genome: replication starts at origin and proceeds around the circle to completion
In linear mammalian chromosomes, when replication fork reaches the end, RNA primer can’t be placed for the last Okazaki fragment
Once the RNA primer is removed from the 5’ end, it cannot be filled up.
No polymerase available with 3’-5’ activity
5’ ends will shorten after each replication cycle
What will be the consequences?
Coding sequences may be eventually lost
Senescence or death signal may be triggered
Does not occur in circular, bacteria, DNA

107
Q

Telomeres

A

seal the end of chromosomes to prevent undesirable fusion and aberrant recombination, attach chromosomes to nuclear envelope, facilitate replication

108
Q

Telomerase

A

RNA dependent DNA polymerase (reverse transcriptase), made of ribonucleoprotein and RNA, makes telomeric repeats
Telomeric repeats humans TTAGGG (up to 15 Kb)

109
Q

telomeres and aging

A 
shorter telomeres induce replicative senescence and induce cell death
Somatic cells (differentiated)- no detectable telomerase activity
Germ cells and stem cells- have detectable activity 
Elderly have shorter fibroblast telomeres
110
Q

telomeres and cancer

A

tumors have telomerase activity, inhibition or activity or disrupting structures would prevent tumor growth (effective in mice)
Germ cells also have telomerase activity
-therapeutic agents can inhibit nucleotide synthesis

Ex: thymidylate synthase (TS) converts dUMP to dTMP
5-Flurouracil inhibrits TS (Capecitabine (Xeloda)- chemo agent)

111
Q

AZT as a therapy for HIV replication

A

HIV- RNA virus, requires RNA  DNA, priming tRNA (tRNA-lys), cDNA formation by reverse transcriptase, then inserts into host genome by integrase
Targets for inhibition- replication, integrase, protease
Ex: AZT- analog for deoxythymidine, this prevents DNA chain elongation by reverse transcriptase

112
Q

Role thymidylate synthase in replication, and mechanism of 5-fluoro uracil as chemotherapeutic agent

A

therapeutic agents can inhibit nucleotide synthesis
Ex: thymidylate synthase (TS) converts dUMP to dTMP
5-Flurouracil inhibrits TS (Capecitabine (Xeloda)- chemo agent)

113
Q

Mismatch repair

A

wrong base pairing (methylated at the mistakes)

In bacteria Mut S, L, H
In Euks Mut S- recognizes mismatch, Mut L scans for nicks

114
Q

Depurination

A

removes purine from nucleotide, leads to baseless sugar- P, consequences: leads to deletion

115
Q

Deamination

A

methylated cytosine to thymine, C  U, consequences: changes base

116
Q

UV- consequences:

A

creates pyrimidine dimers form

117
Q

replication repairs

A

3’ to 5’ exonuclease activity, removes mismatched nucleotide

Also stranded-directed mismatch repair when DNA helix is altered

118
Q

post-replication repairs

A 
including transitions, transversions, frameshifts)
Purpose is to correct mismatched basepair
In E coli- methylation
In Euks- single strand breaks, nicks
Errors may occur due to: 
Structural alterations in DNA bases may occur due to:
Cellular metabolic activity
Heat 
Extreme pH
Radiations
Substances in environment
Spontaneous Changes:
Depurination
Deamination
UV damage
Pyrimidine dimers
119
Q

lynch syndrome

A

mismatch repair

hereditary non-polyposis colon cancer (HNPCC)
Mutations in human homologs of mutS (MSH2) and mutL (MLH1) are involved.

120
Q

BER

A

specific base removed and repaired, (ex. Uracil DNA Glycosylase)

121
Q

NER

A

stretch of DNA strand is removed and new strand with correct base is made (ex excision nuclease)

122
Q

missmatch repair

A

repair of non-Watson-crick basepairs

123
Q

double stranded break

A

see photo

Double strand breaks occur during:
Recombination (RAG-recombination activating gene-proteins catalyzing recombination of immunoglobulins)
Ionizing radiation, oxidizing agents 
Double strand breaks are repaired by:
Non-homologous end-joining (NHEJ)
Involves Ku protein, DNA-PK and Artemis
Homologous end-joining (HEJ)
Involves BRCA1 and BRCA2
124
Q

repair defect cause diseases

A 
Xeroderma pigmentosum (XP)
Skin malignancies
Cockayne syndrome (CS)-ERCC6/ERCC8 mutation
Premature aging, photosensitivity, hearing loss etc.
Breast cancer (BRCA1 and BRCA2)
17q21 and 13q12
Werner syndrome (WRN RecQ helicase mutation-helicase/exonuclease activity)
Cataracts, short stature, premature graying etc
Bloom syndrome (BLM RecQ helicase mutation-helicase activity only)
Stunted growth sunlight sensitivity, chromosome breakage, increased cancer risk etc.
125
Q

Transition state theroy

A

activation barrier to binding the substrate, but once bound that activation barrier is lower, making the reaction more likely and the rate of reaction increases. It is the reduction in the activation barrier, and not the chemical potential, that increases the rate of reaction.

126
Q

allosteric enzymes

A

multiple subunits
bind far from active side
S shaped sigmoidal substrate-velocity relationship

large change in activity over a narrow range of substrate concentrations

127
Q

Michaelis-Menton

A

hyperbolic substrate velocity relationship

128
Q

know inhibitor graphs and ES thing

A

know enzyme graphs`

129
Q

regulatory mechanisms to modify enzymes

A
  • Substrate concentrations
  • Allosteric regulators
  • Post-translational modifications (e.g., phosphorylation)
  • Abundance (i.e., translation/transcription or proteolysis)
130
Q

competitive inhibitor

A

Vmax- no change

Km- increases

131
Q

noncompetitive inhibitor

A

Vmax- decreases

Km- no change

132
Q

uncompetitive (mixed) inhibitor

A

Vmax- decreases

Km- decreases

133
Q

competitive inhibitor examples

A
  • statins (HMG-CoA reductase)
  • methyltrexate (dihydrofolate reductase)
  • Salicylate (cyclooxygenase 2, COX 2)
134
Q

noncompetitive inhibitor examples

A
  • cynaide (cytochromes)
  • D-JNKI-1
  • Nifedipine (CYP2C9)
135
Q

uncompetitive (mixed) inhibitor examples

A
  • pepstatin
  • trypsin inhibtor (trypsin)
  • ethanol (acid phosphatase)
136
Q

irreversible inhibitors

A

example: aspirin

Aspirin covalently modifies COX-1 and COX-2 by acylation of Ser near active site (blocks prostaglandin biosynthesis).

Advantages of covalent drugs include:
Selectivity
Lower doses and side effects
Prolonged duration of inhibition
Lower risk of drug resistance due to active site residue changes

Covalent drugs target more than 39 enzyme targets include:
H+/K+ ATPase (gastric acid)
β-lactamases (antibiotic detoxification)

137
Q

enzyme regulatory mechanisms

A
  • Allosteric Effectors (e.g., fructose-2-phosphate); Very Fast
  • Post-translational Modifications (e.g., enzyme phosphorylation); Fast
  • Enzyme Abundance (transcriptional regulation); Slow
138
Q

Zygote

A

fertilized egg, after nuclear fusion

139
Q

pre-implantation stages

A

first 2 weeks, zygote; 2-8 cell stages morala, blastocyst, bilaminar disc

140
Q

embryo

A

developing organism from 2-8 wks EDF

141
Q

fetus

A

developing organism from 9 wks to birth EDF

142
Q

trimester

A

1/3 of the human gestational periods, not related to developmental stages

143
Q

growth

A

Increase in cell number, cell size, and extracellular matrix

144
Q

differential growth

A

one side or part of a structure grows faster than another

145
Q

induction

A

a chemical signal (surface signaling molecule or chemical released into extracellular matrix) will cause a change in cells resulting in migration differentiation or other change

146
Q

cell differentiation

A

nonspecialized to specialized cells, some genes are activated (determination), others inactivated (restriction), usually permanent, metaplasia (pathologic de/re differentiation)

147
Q

Selective cell death

A

cells are programed to die for structure to develop normally, example hand cells between fingers die and brain large number of cells die in fetal life

148
Q

migration

A

physical movement of cells from one location to another, usually involves amoeboid movement and chemotaxis

149
Q

epithelial folding

A

upon appropriate induction, the edges of some type of poorly differentiated, flat epithelia can fold over on themselves to form a tube, example neural tube with actin filaments

150
Q

cavitation/canalization

A

opening of spaces in originally solid tissues as the cells move to a peripheral location

151
Q

morphogens

A

Diffusible molecules that create gradients which act directly on cells for specific developmental responses.

152
Q

notch signaling pathway

A

conserved intercellular signaling pathway using direct cell-to-cell contact.

153
Q

transcription factors

A

Binds to DNA, initiates transcription of mRNA. Many are Homeobox or HLH families.

154
Q

receptor tyrosine kinsases

A

Cell-surface receptors, includes growth factors which regulate cell migration, proliferation, and apoptosis, new growth, etc. (also in normal cells, where they involve cytokines and hormone receptors)

155
Q

important classes of developmental factors commonly involved in human development (4)

A
  • morphogens
  • notch signaling pathyway
  • transcription factors
  • receptor tyrosine kinases
156
Q

Meiosis

A

chromosomes 1 DNA replication, 2 divisions(4n to 2n (2 copies of 23 chromosomes) to n)

Gametogonium- 46 replicated chromosomes, divides by standard mitosis, daughter calls may differentiate into primary gametocytes
Gameotyocytes- 46 chromosomes which line up in homologous pairs (4n), divides in division I to form secondary gametocytes with 23 replicated chromosomes (2n)
Division II to form two gametes a piece (4 total) each with 23 nonreplicatd chromosomes (n)

157
Q

mitosis

A

All cells
1 DNA replication, 1 division (4n to 2n( 46 complete chromosomes)
IPMAT

158
Q

Spermatogenesis:

A

Spermatogonia undergo mitosis

Primary and secondary spermatocytes undergo meiosis

Spermiogenesis is the morphological differentiation of spermatids into spermatozoa.

159
Q

Oogenisis:

A

Primary oocyte 46, xx
Secondary oocyte 23, x a primary oocyte also forms a polar body to get rid of secondary DNA
Ovum 23, x meets with sperm 23 x or y
Zygote 46, XY or XX

160
Q

transcription growth factor beta (TGF-b)

A

example of morphogen

promotes cell growth and differentiation; uses SMAD pathway. Think angiogenesis, Mesoderm migration, Axons.

161
Q

Bone Morphogenic Proteins (BMP’s):

A

one of the pivotal developmental signaling molecules; think cell differentiation.

162
Q

Hedgehog series: (e.g. SHH)

A

critical developmental gene requires cholesterol to become active. SHH; think development of vertebrae, paraxial mesoderm.

163
Q

WNT (Wingless-related integration site):

A

Critical in pattern development and axis patterning among other things, it uses β-catenin to activate gene sequences. Think muscle development.

ISOM (9 decks)

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