quiz #2 Flashcards
Four Bases of DNA
Adenine Cytosine Guanine Thymine
Purines
-have a pyrimidine + imidazole group combined
-structure: 3 & 5 C chain
Purines (example)
Purine,Adenine,Guanine
Pyrimidine
have 4C and 2C in aromatic ring
Pyrimidine (example)
Pyrimidine,Cytosine,Thymine
Base+Sugar
Nucleoside
Purine Nucleosides
end in “sine” (ex.adenosine,guanosine)
Pyrimidine Nucleosides
end in “dine” (ex.cytidine,thymidine)
In DNA Nucleosides are attached by a…
Phosphodiester Backbone
Nucleosides with phosphate groups are called
Nucleotides
Nucleotides are like the “….” of DNA.
amino acids
Watson Crick Base Pairing
1) hydrogen bonds
2) purine/pyrimidine
3)GC has 3 H-bonds
4)AT has 2 H-bonds
deoxy-
nucleotides found in DNA
DNA is
Antiparallel, right handed double helix, major and minor grooves
ribose (sugar)
OH on 2’
Base pairing for RNA
GC base pair
AU base pair
messenger RNA (mRNA)
codes for 1 sequence of proteins
transfer RNA ( tRNA)
binds amino acids & mRNA
ribosomal RNA (rRNA)
part of ribosome, which assembles polypeptides
Messenger RNA (mRNA) is almost identical to
the coding strand DNA
gene
coding DNA contains a functional unit of heredity that “codes” for the 1 sequence of a protein or RNA
Coding region codes for
each amino acid
histones organize what?
organize DNA
exon
coding DNA
introns
noncoding DNA
Open Reading Frame(ORF)
exons together
Protein Synthesis Starts with
Transcription
pre-mRNA
exons+introns
mature transcript
5’ cap + exons+ poly-A tail
untranslated region
cap and poly-A tail in 5’ and 3’ UTR
mRNA coding regions are EXACTLY the same as
DNA exons
Transcription and Splicing Occur in
the nucleus
codon
3 Nucleotides
Each codon(4^3 = 64) codes for an
amino acid or STOP codon
START codon is
M ( which is the initiator codon)
Anticodon is the
“opposite” sequence of mRNA
Always write Nucleic Acids from
5’ to 3’
Wobble Effect
explains at a biochemical level why the genetic code is degenerate
Translation occurs in the
cytoplasm
Protein Synthesis
Translation
Fat
Fatty Acids and Triglycerides
Lipids are
FA and trglycerides, phospholipids, bile/cholesterol
Saturated FA
no double bonds
Unsaturated FA
consecutive double bonds (usually cis)
that last carbon in a FA chain is called
the omega carbon (w)
FA names start with the
carboxylic acid group
Palmitate
C16:0
largest FA made by FASN
Arachidonate
C20:4
laureate
saturated FA
Palmitoleate
unsaturated FA
SDS is
-Sodium lauryl sulfate (SDS)
-saturated
Olen or Olestra
fat substitute to mimic oleate= ionized form/conjugate base of oleic acid
-unsaturated
cis double bond makes
a kink
FASN
Mammalian Fatty Acid Synthase
FASN is a
-quaternary protein + homodimer
-Sole enzyme responsible for de novo synthesis of long chain fatty acid
Acyl CoA has a
thioester bond attached to an acyl
A type of Acyl CoA is
Acetyl CoA
Acetyl CoA has a
thioester bond attached to an acetyl group
Acetyl CoA is a an activated coenzyme required for
fatty acid synthesis
Acetyl CoA is derived from
vitamin B5, glycolysis, FA and aa degradation
Acetyl CoA initiates
citric acid cyle
Acetyl CoA is more or less stable than an ester bond?
less
NADPH is required as an
electron donor for reduction reactions
Carbon Accounting
keeping track of how many carbons are present in each of the metabolites
synthesis of palmitate is made by a
anabolic process ( like protein synthesis)
FA synthesis Step 1
acetyl coA (2C) is oxidized to malonyl CoA (3C) by acetyl CoA carboxylase
-high regulated
ACC
Acetyl CoA Carboxylase
ACC1 inhinited by phosphorylation by
AMP dependent protein kinase
Pallmititoyl CoA(final product) inhibits
feedback inhibition ( recurring theme in enzymology & therefore metabolism)
FA Synthesis Step 2
-building the ACC
-Acetyl CoA (2C) and Malonyl CaA (3C) are loaded into a large ensyme complex called FASN
-joined together to make a 4C chain via ketoacyl synthase KS (CO2 is lost during condensation)
- process is repeated w, new malonyl joined to the C4 butyryl
How many enzymatic reactions does FA synthesis have in one round?
7
How many carbons does the product have in the FA biosynthesis?
4
KS
ketoacyl sythase
Mat
malonyl transferase
KR
ketoreductase
DH
dehydratase
ER
enoyl reductase
Why do we need 8 Acetyl CoA instead of 7?
malonyl CoA needs to be made
Fatty Acids can be used to construct
phospholipids for membrane synthesis
Fatty Acids can be stored in the form of
triacylglycerol or triglycerides
Phospholipids are
Amphipathic (very hydrophobic glycerol &hydrophilic head group)
Triacylglcerol or Triglyceride
storage form of FA in fat cells
intergral protein
embeded in the membrane had to get dettached
peripheral protein
located on the inner part of the membrane
endocytosis
Receptor binding on the surface of the cell induces the membrane to invaginate
Do Prokaryotes have membranes?
Yes , they have an outer and inner membrane or a thick cell wall
Permeability barrier
keep stuff in and keep stuff out
Protein Solvent
membrane is able to “dissolve” proteins . “garage for hydrophobic car”
Asymmetry
more of compound on the outside of the cell compared to the inside (vice versa)
Fluidity/Signaling
diffusion, concentrate proteins and lipids in 2 dimensions
Unsaturated FA C18:0 + C18:1
oleate, cis
creates high fluidity (kink)
Higher Tm =
high chain length and high saturation
cholesterol
membrane fluidity
LDL
transport mechanism of cholesterol
Cholesterol concentration impacts
stacking and membrane fluidity
Key Cholesterol Functions (4)
1.Membrane Fluidity
2.Precursors of vitamin D(COVID-19)
3.Precursor of bile salts for digestion
4.Precursors of steroid hormones such as testosterone and estradiol
Excess Cholesterol is linked to
Cardiovascular diseases such as atherosclerosis
What was the leading cause of death in the US compared to all cancers combined?
heart disease not including stroke
Anti-platelet drugs (ex.aspirin, clopidogrel)
the standard care for patients at high risk for thrombosis
What drugs competitively inhibit HMG CoA Reductase?
Statins (Lovastatin)
HMG CoA + 2 NADPH + 2H+
Mevalonate + NADP+ + CoA
Cushing syndrome
excess cortisol
