Biochemistry Flashcards
Protein functions
Catalytic Structure Transport Mobility Immunity Communication
Primary protein structure
Unique sequence of amino acids arranged to form polypeptide chain
Secondary protein structure
Maintained by hydrogen bonds formed between carbonyl oxygen and amine hydrogen in the polypeptide backbone
Secondary protein structure no regular patterns
Bends
loops
Turns
Tertiary protein structure
Pattern of the secondary structural elements folding into unique 3D conformation.
Maintained by interactions between side chains of aa
Quaternary protein structure
Association of individual polypeptide chain subunits in a geometrically and stoichiometrically specific manner.
Dimer vs tetramers
Protein structural classification
Globular proteins- myoglobin
Fibrous protein - collagen
Transmembrane proteins - GPCR
Protein denaturation
Destruction of protein’s quaternary, tertiary and secondary structures
N
What affects protein denaturation
Nonenzymatic modifications (glycosylation, oxidation, etc)
High temperature
Very low or very high pH
Oxidoreductases
Catalyze oxidation reduction reactions
Lactate > pyruvate
Transferases
Catalyze transfer of c n or p containing groups
Serine> glycine
Hydrolases
Catalyze cleavage of bonds by addition of water
Urea> nh3 and co2
Lyases
Catalyze cleavage of cc CNS and certain cn bonds
Pyruvate> acetaldehyde
Isomerases
Catalyze arrangement of optical or geometric isomers
Methylmalony coa> succinylcholine coa
Ligases
Catalyze formation of bonds between carbon and o s and n. Couples to hydrolysis of high energy phosphates
Pyruvate> oxaloacetate
Synthase
No atp required
Synthetase
Requires atp
Oxidase
Uses o2 as acceptor without incorporating it
Oxygenase
One or both o2 atoms are incorporated
Phosphatase
Uses h2o to remove phospho group
Phosphorylase
Uses pi to break bond and generate phosphorylated product
Cofactors
Non protein components Inorganic substances that are required for or increase the rate of catalysis Zn2+ Mg2+ Fe3+ Fe2+
Coenzymes
Non protein enzyme component Organic molecules that are required by certain enzymes to carry out catalysis Vitamin derivatives NAD+ FAD NADP+ CoQ CoA
Holoenzyme
Enzyme + non protein component = active
Apoenzyme
Enzyme without non protein component = inactive
Enzyme property function
Efficiency
Extremely high. 10^3 to 10^14 faster than uncatalyzed reactions
K cat
Turnover number.
Number of substrate molecules converted to product per enzyme molecule per second
Enzyme properties function
Specific
Highly specific
Only one or a few substrates
Only one type of chemical reaction
Set of enzymes present in cell determines which reactions will occur in that cell
Free energy
Gibb’s free energy
Quantitative measure of the energy transfers between chemical reactions
Free energy of activation
Difference in free energy of reactants and high energy intermediate.
How do enzymes work
Enzymes work by lowering the free energy of activation without affecting the energies of the reactants and products.
Do NOT change the equilibrium, but accelerate the rate at which equilibrium but accelerate the rate at which equilibrium is achieved
Factors affecting reaction velocity
Temperature
Ph
Substrate concentration
Reaction velocity ph
For human enzymes ph optimum is dependent on enzyme localization
Affects ionization of the active site and enzyme integrity
Allosteric enzymes concentration curve
Allosteric enzymes show a sigmoidal curve.
Some enzymes have allosteric regulators that bind a different site on molecule and change enzyme activity
Michaelis menten kinetics
Model to describe how reaction velocity varies with substrate concentration at a given concentration of enzyme.
Must assume:
[s] is much greater than [e]
[es] does not change with time.
No pack reaction from product to substrate
What must you assume with the michaelis menten kinetics
[s] is much great than [e]
[es] does not change with time
There is no appreciable back reaction from product to substrate
Km
Defined as amount of substrate need to half maximal velocity
what only form of proteins are found in the human body
l amino acids
which amino acids are nonpolar alipathic
glycine alanine proline valine leucine isoleucine
which amino acids are aromatic
phenylalanin
tyrosine
tryptophan
which amino acids are sulfur containing
methioine
cysteine
which amino acids are polar uncharged
asparagne
glutamine
serine
threonine
which amino acids are negative/ acidic
aspartate
glutamate
which amino acids are positive/basic
arginine
lysine
histidine
what is the 21st amino acid
seleniumcysteine
modified aa
posttranslational
nonpolar alipathic acids
highly hydrophobic glycine alanine proline caline leucine isoleucne
aromatic acids
hydrophobic, though try and trp and a little more hydrophilic
phenylalanine
tryptophan
tyrosine
tyrosine is the precursor for
catecholamines
polar uncharged aa
highly hydrophilic groups can be modified (phosphorylation, glycosylation) asparagine glutamine serine threonine
sulfur containing groups
able to sulfide bond
methione
cysteine
methionine
serves as a methyl donor for methylation
cysteine
hghly reactive and easily oxidized
essential amino acids
cannot be synthesize in humans histidine methionine threonine valine isoleucine phenylalanine truptophan leucine lysine
Gluconeogenic
Alanine Arginine Asparagine Aspartate Cysteine Glutamate Glutamine Glycine Proline Serine Histidine Methionine Threonine Valine
Glucogenic and ketogenic amino acids
Tyrosine
Isoleucine
Phenylalanine
Tryptophan
Ketogenic
Leucine
Lysine
DNA
Storage of genetic information
RNA
Mediator in the expression of genetic information
Purines
Adenine
Guanine
Pyrimidines
Cytosine
Uracil
Thymine
Nitrogenous bases
Adenine Guanine Cysteine Thymine Uracil
Nucleoside bases
Adenosine Guanosine Cytidine Thymine Uridine
3 5 phosphodiester bonds
Formed between the oh group on c3 of one sugar and c5 on next one
Link nucleotides together forming backbone of rna and dna polymers
N glycosidic bonds
Formed between the nitrogenous bases and c1 of sugar
Orientation / directionality of dna rna
5’ end = phosphate group
3’ end = hydroxyl end
Nucleoside
Ribose and nitrogenous base
N glycosidic bonds
Formed between nitrogenous bases and c1 of sugar
Double helix Watson and crick model
2 allele complementary strands
2 deoxyribose phosphate backbones
N bases bond to one another by h bonds
B dna
Watson and crick
Majority of dna
Right handed helix
10 base pairs per turn
A form
Right handed helix
11 bp per turn
More compact
Z form dna
Left handed helix
12 bp per turn
Chargaffs rule
Complementary
A=t
g= c
How many bonds does at have
2 h bonds
How many bonds does gc have
3 h bonds
DNA denaturing alkali
Remove surname contamination of dna
Denaturation of dna heat
Melt
Melting temperature temperature 50% of dna is separated
DNA packaging and organization nucleoside
DNA 146 bp
Histidine proteins (arg and lys)
8 core histones
H1 linker histone
Euchromatin
Relaxed transcriptionally active
Lightly stained
Heterochromatin
Highly condensed inaccessible for transcription
Dark stained
Chromosome
Highly condensed form
Visible in metaphase only
DNA accessibility
All cells within organism have same dna but different chromatin structure which determines tissue specific function
Because different cells need different genes for different proteins and functions.
When dont need the genes > heterochromatin
Control of dna accessibility further condense
Methylation of dna further condenses dna
How dna relaxes dna
Acetylation of histones
So dna relaxes and is able to be transcribed.
Mitochondrial dna
Circular double stranded High mutation rate Contains very few untranslated sequences Encodes 13 protein subunits - for etc Large and small MT rRNAs 22 MT tRNA molecules Genetic code differs slightly from standard code
Deviations of genetic code in mtDNA
Uga standard stop codon is read as trp
Aga and agg (standard codons for arg) are read as stop codons.
Rna general structure
Single stranded linear molecule
5>3 direction
Uracil instead of thymine
Hairpin loops (intramolecular double stranded regions)
Major types of rnas in human cells
Messenger rna Transport Ribosomal Micro Others- snRNA, snoRNA, piRNA, incRNA, siRNA
Messenger RNA
Coding RNA
Carries genetic info from DNA to ribosomes for use in protein synthesis
Transport RNA
No coding RNA
Present amino acids to the ribosomes for synthesis of polypeptide chain
Ribosomal RNA
No coding RNA
Together with ribosomal proteins form ribosomal usubunits
Micro RNA
No coding RNA
Regulatory functions
MiRNA precursor fragments associate with protein complex
MRNA structure
Mose diverse group in length and base sequence
Monocystronic in eukaryotes
Produced as larger precursor (hnRNA)
Common modifications of mRNA
5’ cap and 3’poly a tail for protection from cytoplasmic nucleases
Splicing of introns
5’ and 3’ utr- regulate localization stability translation efficiency
mRNA function
Carries the genetic info from dna to ribosomes for use in protein synthesis
tRNA structure
Smallest in size
More than 1 tRNA for each aa
Extensive secondary and tertiary structures forming cloverleaf.
3’ acceptor end for aa attachment
Anticodon loop - complementary to respective codon on mRNA
Variable loop
tRNA function
Present aa to ribosomes for synthesis of polypeptide chain
rRna structure
80% of all rnas
Four different sizes
Produced from larger precursors in nucleolus and modified subsequently
Rrna function
Together with ribosomal proteins form small and large ribosomal subunits to carry on protein synthesis
Rna catalysts
Ribozymes
Small rna molecules with catalytic activity
Diverse structures and mods
Rybozymes function
Nuclease
Participate in processing of rrna, tRNA, and mRNA
Rna catalysts rybozymes
Peptides transferase
Part of large ribosomal subunit catalyze condensation condensation of amino acids to form polypeptides
Snrnas
Small nuclear rnas
100-300 nucleotides
Rich in uracil
Form small nuclear ribonucleoprotein particles
Small nucleolus rnas
In nucleolus
Piwi interacting rnas
Form complexes with piwi proteins
Diploid
2n
Two sets of 23 homologous chromosomes
Somatic cells
Haploid
N
One set of 23 chromosomes
Mature gametes
Karyotype analysis
Diagnostic tool to detect chromosome abnormalities in
Genetic diseases
Staging of tumor progression
Gender identification
Structure of human genes
Regulatory region Promoter Exons Introns Terminator - poly a signal 3’ and 5’ utr
Single copy genes
Protein coding dna
Tissue specific- only expresses in particular tissues
House keeping - in all cells. Cytoskeleton.
Satellite dna
Generally not transcribed, highly repetitive cluster together
Alpha
Mini
Micro - trinucleotide repeats > undergo expansion in certain diseases
Dispersed repetitive dna
Lines- long interspersed elements
Sines- short interspersed elements
Transposones
DNA replication cycle
Mitosis Nondividing >cell death G0 Stimulus G1 growth and metabolism dna =2n S dna replication dna = 2n >4n G2 preperation for cell division dna = 4n
DNA replication
Semiconservative
Origin
Replication fork
S phase of cell cycle
DNA replication
DNA replication steps
- DNA strands separate at origin, creating 2 replication forks
- Primers req’d to initiate dna synthesis leading strand begins in direction of replication fork. Lagging strand opposite direction in Okazaki fragments
- Leading strand elongates and second Okazaki fragment made
- Leading strand continues to elongate. Third Okazaki fragment made. First and second Okazaki are connected
DNA polymerase iii
Elongates a new dna strand by adding dNTPs to end of growing chain
Primase
Synthesizes short stretches of rna on lagging strand
Topoisomerase i and I (gyrase)
Remove super oils in helix by transiently cleaving one for both dna strands
Gyrase is bacterial prokaryotes
Target for anticancer drugs and antibiotics
DNA helical
Unwinds short segments of parental duplex dna
DNA ligase
Catalyzes sealing of nicks / breaks remaining in dna on lagging strand
Single strand binding proteins
Prevent premature annealing of ssdna to dsdna
Dnt
Deoxynucleotides
Direction of fork movement
5’ to3’
5’ to 3’ polymerase activities
Free end of new strand 3’ end has free oh. Phosphate is then attached to dnt
3-5 exonuclease activity
DNA polymerase activity
Take out the mistakes of base pairing
Proof reading
Polymerase alpha function
Replication (in a complex with primase and aids in starting primer)
DNA repair
No exonuclease activity
Polymerase delta function
Replication (processive dna synthesis on lagging strand)
DNA repair
3’ to 5’ exonuclease activity
Polymerase epsilon function
Replication (DNA synthesis on leading strand)
DNA repair
3’to 5’ exonuclease activity
Telomerase
Complex of protein test and short piece of rna template
Tert acts as reverse transcriptase
Translocates to the newly synthesized end and process is repeated multiple times
When 3’ overhang is elongated, primase binds and synthesis of the complementary strand is initiated
Telomerase TERT
Active in germ line cells and stem cells
Not activated in somatic cells
Reactivated in disease states
Telomere repeat adds to end of telomere
Reverse transcriptase
Found in retroviruses (rna viruses)
Uses single stranded rna template to make a dna copy (complementary dna)
cDNA is then used to produce complementary strand of double stranded cDNA
Once ds cDNA is produced it can become integrated into human genome.
Upon integration viral genes may be inactive or transcribed - causing diseases (AIDS)
Integration event may also disrupt an adj cellular gene and lead disease
Inhibitors of dna replication
Nucleoside analogs that dont allow nucleotides to be added so cant continue replication
enzyme properties : regulation
availability of substrates post translational modifications enzyme protein production regulation through specific local environment enzyme compartmentalization regulation by allosteric effectors
effectors / modifiers
bind to sites other than the active site noncovalently
alter the affinity of the enzyme for its substrate (affect km)
alter the max catalytic activity (vmax)
alter both
Mutation
Change in genomic sequence
Generally used for disease causing genetic variants
Point mutation
Single base change
Silent mutation
Changes that specifies the same amino acid
Missense mutation
Change that specifies different amino acid
Nonsense mutation
Change that produces stop codon
Insertion mutation
An addition of one or more bases
Deletion mutation
Loss of one or more bases
Polymorphism
Genetic variant in which the rare allele occurs with a frequency of at least 1% in population
Independent of the functional or pathogenic relevance of this alteration
Single nucleotide polymorphism
Snps
Number of alleles
Substitution of one or another base pair at a particular location in genome
Number of alleles: usually 2
Insertion/deletion polymorphism
Indels
Simple vs microsatellites
Number of alleles
Simple: presence or absence of short segment. Number of alleles:2
Microsatellite: generally 2,3,4 nucleotide unit repeated in tandem 5-25 times. Number of alleles: typically 5 or more
Copy number variants
Number of alleles
Typically presence / absence of 200 bp to 1.5 mb segments of dna. Although tandem duplication of 2,3,4 or more copies can occur
2 or more alleles
Inversions
Number of alleles
A dna segment present in either two orientations with respect to surrounding dna
2 alleles.
Types of point mutations
Base substitution
Transition
Transversion - Base addition , base deletion
Transition base substitution
One purine is changed to the other purine or one pyrimidines is changed to other pyrimidine
Transversion
Purine is changed to pyrimidine or vice versa
Types of mutations and their frequency
Missense
50%
Deleterious with medical significance
Mutation and frequency
Nonsense
10%
Produces truncated protein
Deleterious with medical significance
Mutation and frequency
Frameshift
25%
Deleterious with medical significance
Mutations that are deleterious with medical significance
Missense Nonsense Frameshift Rearrangements Dynamic mutations Rna processing
Clinical consequences of mutations
Somatic vs Germline
Somatic cells - made lead to cancer
Germline cells - transmitted to offspring
Molecular consequences of dna mutations
Gain of function mutation produces novel or excess protein product
Loss of function mutation reduces or eliminates protein product - need 2 alleles for complete loss of function
Dominant negative mutation (allele 2) produces abnormal protein product that interferes with normal protein produced by allele 1
Sources of dna damage
Endogenous
Mistakes during replication
Basal mutation rate
Tautomeric shift
Sources of dna damage
Exogenous
Ionizing radiation - uv sunlight, x ray, radioactive agents
Hydrocarbons - cig smoke
Reactive oxygen species
Chemotherapy agents
Types of mutation consequence
Lethal and silent
No medical significance
Happen early in development but as so detrimental that there is no more organism development
Miscarriage
Basic mechanisms of dna repair
DNA proofreading
Mismatch repair
Excision repair
Dsdna repair
DNA repair: proofreading
Polymerase function
Incoming nucleoside triphosphate is correctly matched to its complementary base on dna template and is added to monophosphate to growing dna chain
Enzyme advances
DNA repair: proofreading
Proofreading function
If DNA polymerase mispairs nucleotide with template, uses 3’>5’ exonuclease activity to excise mismatched nucleotide
DNA repair
Mismatch repair
Newly replicated daughter strand contains g mismatched to t in parent strand (g and t not hydrogen bonded)
DNA mismatch
Repair proteins
Removal of newly synthesized strand and DNA polymerase and ligase repair
Dysfunctional dna mismatch repair
Hereditary nonpolyposis colorectal cancer (aka hnpcc or lynch syndrome)
Features and type of repair defect
Proximal bowels tumors, increased susceptibility to several other type of cancer
Mutations in any of 6 dna mismatch repair genes
Mismatch repair
Repair proteins
Msh2 Mlh1 Msh6 Pms1 Pms2
Trinucleotide repeat expansion
Huntington’s disease
Tandem repeats of cag, coding for glu.
Aggregated protein polyglu
Trinucleotide repeat expansion
Fragile x
Cgg repeat in utr
Trinucleotide repeat expansion
Monotonic dystrophy
Cug repeat in utr
Trinucleotide repeat expansion diseases
Huntington’s disease
Fragile x
Monotonic dystrophy (classic / type1)
DNA excision repair options
Nucleotide excision
Base excision
Tautomeric shift
Isomerize of nitrogenous base
Dysfunctional dna repair
Xeroderma features and repair defect
Features: skin tumors, photosensitivity, cataracts, neurological abnormalities
Type of repair defect: nucleotide excision repair defects, including mutations in helicase and endonuclease genes
Dysfunction dna repair
Cockayne syndrome
Features and type of repair defect
Features: reduced stature, skeletal abnormalities, optic atrophy, deafness, photosensitivity, mental retardation
Type of repair defect: defective repair of uv induced damage in transcriptionally active dna, considerable etiological and symptomatic overlap with xeroderma pigmentosum and trichothiodystrophy
Nucleotide excision
Pyrimidine dimer Uv specific endonuclease Nicks strand Removal of damaged oligonucleotide DNA polymerase places deoxynucleotides DNA ligase seals up
Base excision
Switches only the base out.
DNA replication
Makes dna copies that are transmitted from cell to cell and from parent to offspring.
Transcription
Produces rna copy of a gene
Messenger rna
Temporary copy of a gene that contains info to make polypeptide
Translation
Produces a polypeptide using information in mrna
Central dogma
Replication (DNA)
Transcription (RNA)
Translation (protein)
Transcription steps
Initiation
Elongation
Termination
Difference between structures of prokaryotes and eukaryotes
Prokaryotes: structural genes transcript multiple proteins (polycistronic)
Eukaryotes: monocystronic.
How does initiation start in eukaryotes
Proteins are bound at the promoter region so polymerase can bind there and transcribe
Which direction is transcription happen
5’ to 3’
Prokaryotic transcription elongation enzyme
Rna pol holoenzyme (4 subunits core)
Rna polymerase i product
Ribosomal rna
Rna polymerase ii product
Messenger rna
Rna polymerase iii product
Transfer rna
Which stand do you use for template strand
Antisense strand
Goes 3’ to5’
mRNA matches which strand
Matches sense strand, the nontemplate strand.
Goes from 5’ to 3’.
Same code (except u)
Transcription termination prokaryotic 2 ways
Rho dependent - requires protein rho
Rho independent - spontaneous doesn’t need additional enzymes. Nascent rna has regions that are complementary to itself so forms hairpin loop, strand separates then.
Rho independent termination pathway
spontaneous doesn’t need additional enzymes. Nascent rna has regions that are complementary to itself so forms hairpin loop, strand separates then.
Eukaryotic transcription termination
Contain poly a polymerase signal
Poly a sequence is transcribed
Termination factors help free rna from poly a site - cpsf cstf
Inhibitors of transcription
Prokayotic
Actinomycin d -antibiotic. Intercalated between dna bases inhibits initiation and elongation
Rifampin binds to rna polymerase and percents chain growth beyond 3 nucleotides.
Eukaryotic inhibits
A amanitin Inhibits rna polymerase ii From mushrooms. No antidote Death
Capping of mRNA
mRNA processing in eukaryotes
mRNA processing Occurs co transcriptionally Decreases rate of degradation Recognition site for binding to ribosome. 5’ end
mRNA processing in eukaryotes
Capping of mrna 5’ end
Poly a tail 3’ end
Removal of introns
Addition of poly a
mRNA processing in eukaryotes
3’ end
Poly a polymerase adds a with atp used.
40-100 adenosine added
Protects rna from degradation
Removal of introns
mRNA processing in eukaryotes
Splicing
Rich in uracil.
Form snurps
Small nuclear rnas.
Translation genetic code characteristics
Specific Universal Degenerative Continuous Non overlapping
tRNA structure
High % of unusual bases
Extensive secondary and tertiary structures- cloverleaf
Cloverleaf parts on tRNA
3’ acceptor end
- site for aa attachment
Cloverleaf trna structure
Anticodon loop
Complementary to respective codon on mrna.
Codons for start signal
Aug
Methionine
Codon for stop signal
Uaa
Uag
Uga
rRNA function
Together with the ribosomal proteins form the small and large ribosomal subunits to carry on protein synthesis
Unusual bases in trna
Play role in recognition of trna
3 steps of translation
Initiation
Elongation
Termination
Sequences in translation in prokaryotes
Shine delgarno sequence
3 initiation factors
Formulated met
Translation characteristics in eukaryotes
5’ cap directs binding
Many initiation factors.
Protein folding
Spontaneous
Many proteins
Require suitable physiological conditions
Protein folding
Chaperone assisted
Large number heat shock proteins and chaperonins
Funciton as molecular chaperones
Require atp
Proteasomal degradation
Selectively degrade damaged or short lived proteins
Uses ubiquitous modification to target proteins for degradation by cytosol by proteasomes
Energy dependent
Post translational modifications
Carbohydrate addition
Lipid addition
I cell disease
Caused by deficiency in enzyme that phosphorylates mannose at c6.
Autosomal recessive inheritance
Protein mistargeting
Inducible operon
Transcription is usually off but can be stimulated or induced.
Repressible operons
Transcription is usually on but can be inhibited or repressed
Gene expression
Formation of Functional product. Rna or protein.
Prokaryotic regulation
Only at transcription.
Eukaryotic levels of regulation
Epigenetic Transcription Post transcription Translation Post translation
Lac operon cell type
In prokaryotic cells
Lac operon
Glucose only present
Lac operon is off/ repressed
- Repressor protein encoded by lacl gene is always present and bound to operator - blocks rna polymerase
- Glucose inhibits ardently cyclase, cannot form camp complex, cannot initiate transcription.
Lac operon
Lactose only present
Lac operon is on/ induced
- When glucose absent adenylyl cyclase makes camp, camp complex forms, binds to cap binding site, rna can efficiently initiate transcription
- When lactose present - small amount of allolactose (lactose isomer) is produced that binds to repressor and prevents binding to operator
Lac operon
Glucose and lactose are present
Lac operon is off/ uninduced.
- When glucose is present it inhibits adenylyl cyclase, no camp, cant form camp complex, cannot initiate transcription
- When lactose is present - small amount of allolactose is produced that binds to repressor and prevents binding to operator.
- Although repressor is inactive, transcription cannot be initiated because cap site is empty
Transcriptional regulation - eukaryote
Regulatory molecules
Cis acting elements
Part of dna
Core promoter
Regulatory - distal and proximal
Transcriptional regulation - eukaryote
Regulatory molecules
Trans acting
Proteins: transcription factors
General - required to initiate transcription
Specific - regulate how much to be transcribed
Transcriptional regulation by steroid hormones steps
- Binding of steroid hormone to its nuclear receptor causes a conformational change in the receptor that uncovers its zinc finger dna binding domain.
- Hormone receptor complex interacts with specific regulatory DNA sequences such as gre
- Hormone receptor complex in association with coactivator proteins controls the transcription of targeted genes
Post transcriptional regulation
Alternative splicing
Alternative polyadenylation
mRNA editing
mRNA stability
Alternative polyadenylation
mRNA with different 3’ ends, altering.
Ex: prod of 2 different if molecules - igm, igd
mRNA editing
Modification in which 1 base in mrna is altered.
Example: liver and small intestine cells produce apoBs of different length
Rna interference
Mechanism of reducing gene expression by either:
Repressing translation
Increasing degradation of specific mrna s
Rna interference mediated by
Endogenously produced short micro rna - mirna
Exogenous short interfering rnas siRNA
Roles of rna interference
Fundamental role in cell proliferation, differentiation and apoptosis
Widely used as tool in research
Huge therapeutic potential
Translational regulation
Phosphorylated - translation is blocked
Not phosphorylated then translation occurs.
Examples aa starvation, heme deficiency, accumulation of misfolded proteins in rer
Posttranslational regulation
Phosphorylation Hydroxylation Carboxylation Biotinylated enzyme Farnesylated protein Glycosylation
Epigenetic changes to chromatin may result from
Development Environmental chemicals Drugs/ pharmaceuticals Aging Diet
Epigenetic changes may result in
Cancer
Autoimmune disease
Mental disorders
Diabetes
Variations in dna
Transposition
Rearrangements in dna
Transposition
Mobile segments of dna that move in random manner from one site to another on the same or different chromosome Enzyme mediated (transposase) Movement can be direct or replication In genome structural variations
Rearrangements in dna
Play a role in generation of a lot of different immunoglobulins from single gene, providing the diversity needed for the recognition fo an enormous number of antigens.
Transposition clinical correlation
Duchenne muscular dystrophy
Rare cases of hemophilia a
Antibiotic resistance in bacteria
Clinical correlation of rearrangements in dna
Pathological dna rearrangement is seen with chromosomal translocations in which 2 different chromosomes exchange dna segments.
Nonreducing sugar
Both rings are locked
Dietary macronutrients
Carbohydrate
Starch
Polysaccharide - ALL glucose
Dietary macronutrients
Sucrose
Disaccharide - glucose and fructose
Dietary macronutrients
Lactose
Disaccharide - glucose and galactose
Dietary macronutrients
Lipids
Mostly triacylglycerols
Essential fatty acids
Dietary macronutrients
Protein
Non essential and essential amino acids
