From Powerpoints Flashcards
Catabolism: ____________; Anabolism: ____________
Exergonic; endergonic
Converging; diverging
Competitive inhibitor of Suc-DH
Malonate (complex 2)
Rotenone and barbiturates such as amobarbital and amytal inhibit _______
NDAH-DH (complex 1)
Antimycin A and Dimercaprol inhibit _________
Cyt C reductase (complex 3)
Are lipid soluble weak acids; dissolve in the membrane and function as carriers for H+
Uncouplers
Oil drop or mixed micelle model of lipoprotein structure differ in A. Size of the neutral lipid core B. Lipid composition in the core C. Apolipoprotein D. All of the above
D. All of the above
Cofactors for enzymes C-II is for
Lipoprotein lipase
Cofactors for enzymes A-I is for
Lecithin and cholesterol acyltransferase (LCAT)
Enzyme inhibitors for lipoprotein lipase
A-III and C-III
Enzyme inhibitors for cholesteryl ester transferprotein (CETP)
C-1
Ligands for interaction with lipoprotein receptors in tissues for LDL receptor
B-100 and E
Ligands for interaction with lipoprotein receptorsintissues for HDL receptor
A-I
VLDLs are converted to LDL through the action of
Lipoprotein lipase and hepatic lipase
Cholesterol is incorporated into the plasma membranes and excess is re-esterified by
Acyl-CoA-cholesterol acyltransferase (ACAT)
A co-factor for the lecithin-cholesterol acyl transferase (LCAT)
Apoprotein A-1
Apo C and Apo E are synthesized in the
Liver
Major function of HDL
Repository for the ApoC and ApoE required in the metabolism of chylomicron and VLDL
HDL is a scavenger for cholesterol from
Peripheral tissues
Cholesterol esters can be transferred to VLDL and LDL via the action of
Cholesterol ester transfer lipoprotein (CETP) aka apo-D
Fatty acid synthesis requires
Malonyl CoA and acetyl CoA
A three carbon intermediate that initiates fatty acid synthesis
Malonyl CoA
Sources of acetyl CoA
A. Oxidative decarboxylation of pyruvate (carbs)
B. Oxidative degradation of some amino acids (proteins)
C. Beta oxidation of long chain fatty acids (fats)
D. All of the above
D. All of he above
Arrange the steps in fatty acid biosynthesis
- Condensation
- Reduction
- Dehydration
- Reduction
1-2-3-4
What group is reduced to an alcohol by NADPH
Beta-ketogroup
In FA biosynthesis, the elimination of water creates a
Double bond (dehydration)
All the reactions in the fatty acid synthetic process are catalyzed by a multi-enzyme complex called
Fatty acid synthase
How many cycles of condensation and reduction produce the saturated palmitoyl group
Seven
In FA synthesis, this enzyme catalyzes a hydrolisis reaction to release palmitate (16:0)
Palmitoyl thioesterase
FA synthase complex is found exclusively in the
Cytosol
Acetyl CoA production occurs in the
Mitochondria (mitochondrial inner membrane is impermeable to acetyl CoA)
Oxaloacetate cannot return to the mitochondrial matrix directly, so oxaloacetate is reduced to
Malate
Intra mitrochondrial acetyl CoA first reacts with oxaloacetate o form
Citrate
Citrate then passes into the cytosol through the mitochondrial inner membrane on the
Citrate tranposter
In the cytosol, citrate is cleaved by __________ regenerating acetyl CoA
Citrate lyase
Malate returns to the mitochondrial matrix on the _____________ transporter in exchange for citrate
Malate-alpha-ketoglutarate
In hepatocytes and adipocytes, cystosolic NADPH is largely generated by the _________ and by the ____________
Malic enzyme and pentose phosphate pathway
What is the major proton collector? A. NADH B. NAD+ C. NADPH D. A & B
D. A & B
Most important storage form of glucose derive from diet
Triglycerides
Major source of oxaloacetic acid
Glucose
Very important pathway in intermediary metabolism
Tricarboxylic acid
Allows for the complete oxidation of the major biomolecules including glucose
TCA cycle
Alternative pathway used for glucose metabolism for the cells that produce NADPH and other simple sugars
Pentose phosphate pathway
Used as an electron carrier in fatty acid synthesis or lipogenesis
NADPH
Important component of nucleic acids (RNA and DNA)
Ribose
Most important function of carbohydrates and glucose
Role as the only major biomolecule that could be used as a source of energy in the absence of oxygen
True or False: Oxidation of glucose can still continue even without oxygen
True
In the end stage of glycolysis, pyruvate may be converted to lactate with the help of what enzyme
Lactate dehydrogenase
Major storage form of glucose
Fatty acids
Because glycogen remains a polar molecule owing its partially oxidized state. As a result, glycogen is stored in the cell in a highly hydrated form.
A gram of glucose yields
4 kcal
A gram of fat yields
9 kcal
True of fatty acids
Most fatty acids in the body are saturated and highly reduced. They are hydrophobic and could be stored in a highly “dehydrated” state
True or false: glucose may be converted to fatty acids and vice versa
False
Glucose may be converted to fatty acids, but the reverse is not true
The only major contributor to synthesis of new glucose
Amino acids
The only major biomolecule that could be used by cells for energy in the absence of oxygen
Glucose
Regulates glucose, fatty acid and amino acid metabolism, but responds primarily to serum glucose levels
Insulin
Other hormones that respond primarily to glucose levels but affect not only carbohydrate but also fatty acid and amino acid metabolism
Thyroid hormone, epinephrine, glucagon
Insulin is released by what when serum glucose starts to increase
Beta cells of the pancreas
Insulin stimulates entry of glucose in certain cells as well as ________, ________ and ________
Glycogen synthesis, fatty acid synthesis and protein synthesis
Insulin inhibits what
Lipolysis, beta-oxidation and gluconeogensis
Saliva contains what
Amylase
Absorption of glucose through the intestines occurs primarily through
Facilitated transport
What glucose transporter is found in adipose tissue and skeletal muscle that is stimulated by insulin
Glucose transporter 4
Glucose transporter that is ubiquitous, expressed to largest degree in the brain, placenta and most cultured cells
GLUT1
Glucose transporter in liver, beta cells of pancreas and kidneys
GLUT2
Glucose transporter that is ubiquitous
GLUT3
Glucose transporter found in adipose tissue, heart and skeletal muscle
GLUT4
Glucose transporter found in small intestine
GLUT5
Glucose is immediately phosphorylated to glucose 6 phosphateby what enzyme
Hexokinase (glucokinase in the liver)
Which traps glucose inside the cell as G6P is more highly polarized that glucose and is of significantly larger size
Conversion to G6P
Decreases the concentration of glucose inside the cell, thus allowing for more glucose to enter
3 fates of G6P
Could be used in the pentose phosphate pathway to produce ribose and other sugars, used in glycogen synthesis, undergo glycolysis
Major energy producing reaction in carbohydrate metabolism and the initial stage in the conversion of glucose into fatty acids
Glycolysis
Enzymes that catalyze the conversion from glucose to glucose 6 phosphate
Hexokinase (in non-hepatic tissues) and glucokinase (in the liver)
Difference between glucokinase and hexokinase
Glucokinase has a higher Km that hexokinase and is not inhibited by G6P.
Hexokinase is neither regulated by insulin nor glucagon.
When serum glucose and insulin levels are high, the G6P ends up being stored as
Fatty acids and glycogen
When insulin levels are low, the glucose that is extracted is used for energy through
Glycolysis
The signal for glycogenolysis in the skeletalmuscle is
Epinephrine
The forward reaction is catalyzed by
Phosphofructokinase (PFK1)
The reverse reaction is catalyzed by
Fructose 1,6 biphosphatase
The phosphate donor is
ATP
So that the forward reaction is highly endergonic
Fructose 2,6 biphosphate stimulates
Phosphofructokinase 1 (glycolysis part)
Fructose 2,6 biphosphate inhibits
Fructose 1,6 biphosphatase (gluconeogenesis part)
Phosphoenol pyruvate —> pyruvate
Is strictly an irreversible reaction with the corresponding reactions in gluconeogenesis proceeding very differently
Phosphoenol pyruvate —> pyruvate is catalyzed by what enzyme and produces how many ATP
Pyruvate kinase and one ATP
Once pyruvate is formed, it is transported into the mitochondrion where it is converted to acetyl CoA by what enzyme
Pyruvate dehydrogenase
Strictly irreversible reaction and also explains why fatty acids could never be converted back to new glucose
Pyruvate kinase is inhibited by ATP and the amino acids _______ and ________
Alanine and phenylalanine
Acetyl CoA causes inhibition of pyruvate dehydrogenase by stimulating the
Pyruvate dehydrogenase kinase
Inhibits the kinase and activates PDH
Pyruvate
Oxaloacetate is easily converted to malate inside the mitochondrion by the enzyme
Malate dehydrogenase
Oxaloacetate is converted to phosphoenol pyruvate by the enzyme
PEP carboxykinase
Whole pyruvate -> PEP cycle consumes _______ while the reverseprodices only
2 ATP equivalents; 1ATP resulting in a net requirement of 1ATP
Insulin is responsible for
Protein synthesis
Glucagon is responsible for
Amino acid breakdown
Whereas glucose is the substrate for glycolysis, kt is the product of
Gluconeogenesis
The substrates for gluconeogenesis are the amino acids while the products of glycolysis are
ATP and NADH2
Step which determines the flux between glycolysis and gluconeogenesis
Fructose-6-phosphate: fructose 1,6 biphosphate substrate cycle
Removal of the phosphate group is done by this enzyme
Glycose 6 phosphate
Found only in the liver and to a lesser extent in the renal cells
Glycogen metabolism is controlled by regulation of the enzymes
Glycogen phosphorylase (involved in glycogenolysis) and glycogen (involved in glycogenesis)
The activation of protein kinase b is done in the presence of high levels of cyclic AMP, formed from ATP by the enzyme
Adenyl cyclase
Roundabout way of activating glycogen phosphorylase with a signal from glucagon or epinephrine is called
Amplification
The enzyme catalyzing the first reaction in fatty acid synthesis (the conversion of acetyl CoA to malonyl CoA
Acetyl CoA carboxylase
When fatty acid synthesis from glucose is taking place, degradation of fatty acids through beta-oxidation in the mitochondrion is prevented by inhibition of carnitine palmitoyl transferase I (CPT I) by ________
Malonyl CoA
Processes which allow for utilization and storage of glucose
Glycolysis and glycogen synthesis
Allows for regeneration of glucose
Glycogenolysis and gluconeogenesis
Inside the enterocytes, the lipids are aggregated into what
Chylomicrons
Enzyme that converts the surface phospholipid and cholesterol into cholesterol esters and lysolecithin
Lecithin cholesterol acyltransferase (LCAT)
Cholesterol is eliminated from the liver by being exerted as what
Bile acids
Involves the hydrolytic removal of the fatty acid moiety from the glycerol backbone of triglycerides
Lipolysis
The opposite process of lipolysis where fatty acid molecules are added to the glycerol backbone
Esterification
Cholesterol has role in
Atheroscelrosis and cardiovascular disease
Regulation of cholesterol synthesis is exerted at the step catalyzed by what enzyme
HMG CoA reductase
Multiple generations affected
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
A. Autosomal dominant inheritance
Males and females equally likely to be affected
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
B. Autosomal recessive inheritance
The incidence of the condition is much higher in males than in females
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
C. X-linked recessive inheritance
A male or female child of an affected mother has a 50% chance of inheriting the mutation and thus being affected with the disorder
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
D. X-linked dominant inheritance
Males and females affected in equal proportion
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
A. Autosomal dominant inheritance
Both parents must be carriers of a single copy of the responsible gene in order for a child to be affected
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
B. Autosomal recessive inheritance
All daughters of affected males will be carriers
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
C. X-linked recessive inheritance
All female children of an affected father will be affected (daughters possesses their fathers’ chromosome)
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
D. X-linked dominant inheritance
Male to male transmission does occur
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
A. Autosomal dominant inheritance
The risk is 25% for each child of carrier parents
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
B. Autosomal recessive inheritance
Sons of carrier females have 50% chance of being affected, 50% chance unaffected, in each pregnancy
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
C. X-linked recessive inheritance
Each offspring of an affected parent has 50% chance of being affected
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
A. Autosomal dominant inheritance
Ask about consanguinity
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
B. Autosomal recessive inheritance
The condition is never transmitted directly from father to son
A. Autosomal dominant inheritance
B. Autosomal recessive inheritance
C. X-linked recessive inheritance
D. X-linked dominant inheritance
C. X-linked recessive inheritance
Myotonic dystrophy, fragile X syndrome and Huntington disease are examples of
Triplet Repeat Expansion Disorders
An expansion of a segment of DNA that contains a repeat of 3 nucleotides such as CGGCGGCGGCGG…..CGG is called
Triplet Repeat Expansion Disorders
Only one copy of the gene is expressed, expression of the gene is variable depending on which parent the gene came from, the active gene is preferentially always from one parent over the other
Genomic Imprinting
Stop codons
UAG, UAA, UGA
Base + sugar =
Nucleoside
Base + sugar + phosphate =
Nucleotide
Source of nucleotides that use simple precursors e.g. Amino acids, CO2, one carbon groups
De novo pathways
Source of nucleotides that use preformed nucleosides and bases
Salvage reactions
Is the source of ribose group for de novo purine and pyrimidine nucleotide synthesis and salvage reaction
PRPP (phosphoribosyl pyrophosphate)
Conversion of IMP to GMP and AMP
Branched pathway of biosynthesis of purine nucleotides
What is built up from a molecule of PRPP synthesized from ribose-5-PO4 and ATP
Purine ring
What are the donors of atoms of purine ring
Amino acid and one carbon compounds
Formation of carbomyl phosphate from bicarbonate via
Carbomyl synthetase II (cytosol)
Major site of biosynthesis of purine nucleotides
Liver
Condensation of aspartate and carbamoyl phosphate via
Aspartate transcarbamoylase
Enzyme in pyrimidine biosynthesis
CTP synthetase
4 ribonucleoside diphosphates in the formation of deoxyribonucleotides
ADP, GDP, CDP, UDP
Enzyme in the formation of deoxyribonucleotides
Nucleoside diphosphate reductase or ribonucleotide reductase
A suicide inhibitor used to treat gout
Allopurinol
An estimate of the difference between the amount of nitrogen intake (in the form of dietary proteins) and all sources of nitrogen excretion (primarily as urea and NH4)
Nitrogen balance
What is the average DNA length of chromosomes
1.3 x 10^8 bp (~5 cm)
Diameter of the cell nucleus
10 micrometer
How many chromosomes does humans have?
46
Order of organization of a human genome
10 nm fibril -> 30 nm chromatin fiber -> looped domains -> condensed loops -> metaphase chromosome
Histone octamer for nucleosome formation
H2A and H2B dimers
Histone octamer for nucleosome stabilization
H3 and H4 tetramer
The process of accurate duplication of an organism’s genetic information
DNA replication
Two parental strands separate and serve as template for a new progeny strand because of complementary base pairing
DNA replication
A feature of DNA replication where each daughter DNA has one parental strand and one new strand
Semi-conservative
A feature of DNA replication where it has an anti-parallel DNA and 5’ to 3’ direction of DNA polymerase
Semi-discontinuous
A feature of DNA replication where DNA polymerase cannot initiate de novo synthesis
Priming of DNA synthesis
A feature of DNA replication where two replicating forks move in opposite directions away from the origin
Bidirectional
Deoxynucleotide polymerization
DNA polymerases
Processive unwinding of DNA
Helicases
Relieve torsional strain that results from helicase induced unwinding
Topoisomerases
Initiates synthesis of RNA primers
DNA primase
Prevent premature reannealing of dsDNA
Single-strand binding protein
Seals the single strand nick between the nascent chain and Okazaki fragments on lagging strand
DNA ligase
Equal and reciprocal exchange between homologous chromosomes during meiosis A. Recombination B. Transposition C. Gene conversion D. Mutation
A. Recombination
Jumping DNA; small DNA elements capable of transposing themselves in and out A. Recombination B. Transposition C. Gene conversion D. Mutation
B. Transposition
Pairing of similar sequences on homologous or non homologous chromosomes A. Recombination B. Transposition C. Gene conversion D. Mutation
C. Gene conversion
Eliminate mismatched sequences between them A. Recombination B. Transposition C. Gene conversion D. Mutation
C. Gene conversion
Alteration in the DNA structure that produce permanent changes in the genetic information A. Recombination B. Transposition C. Gene conversion D. Mutation
D. Mutation
The survival of an individual requires genetic stability A. Recombination B. Transposition C. Gene conversion D. Mutation
D. Mutation
Occasional genetic changes contribute to variation and enhances the long-term survival of a species A. Recombination B. Transposition C. Gene conversion D. Mutation
D. Mutation
Proofreading of DNA polymerase A. 5' to 3' exonucleic activity B. 5' to 3' endonucleic activity C. 3' to 5' exonucleic activity D. 3' to 5' endonucleic activity
C. 3’ to 5’ exonucleic activity
Methylation differentiates parental and daughter strands
A. Mismatch repair
B. Base excision repair
C. Nucleotide excision repair
A. Mismatch repair
Usually works on common, relatively subtle changes to DNA bases e.g. Deaminated Cs, alkylated bases, oxidized bases
A. Mismatch repair
B. Base excision repair
C. Nucleotide excision repair
B. Base excision repair
Deals with more drastic changes to bases (pyrimidine dimers)
A. Mismatch repair
B. Base excision repair
C. Nucleotide excision repair
C. Nucleotide excision repair
1% of total cellular DNA and encodes several peptides in the mitochondria, rRN, tRNA e.g. Cytochrome oxidase and ATP synthase
Mitochondrial DNA
Mitochondrial DNA is transmitted by
Maternal non-mendelian inheritance
Development of an entire organism from a cell as long as the genetic material is intact
Cloning
From a primordial cell to a terminally differentiated cell e.g. Skin cell
Cellular differentiation
Change in gene expression without actual change in DNA
Epigenic control
Dense, dark, highly packed (inaccessible), transcriptionally silent
A. Heterochromatin
B. Euchromatin
A. Heterochromatin
Loosely packed (accessible), light, active gene transcription
A. Heterochromatin
B. Euchromatin
B. Euchromatin
Silencing genes, reduces unnecessary gene expression
DNA methylation
High methylation =
A. Transcriptionally silent
B. Transcriptionally active or can be activated
A. Transcriptionally silent
DNA methylation is mediated by
MeCP1 and MeCP2 (methylated CpG binding proteins 1 & 2
Anytime that a cell differentiates, there is an increase/decrease in methylation (de novo synthesis)
Increase
Because differential gene expression is needed
Replication from fertilized egg to blastocyst increase/decrease in methylation
Decrease (demethylation in early embryo)
Inherited form of mental retardation
A. Fragile X syndrome
B. Fragile Y syndrome
A. Fragile X syndrome
Where DNA are wrapped around making it more accessible and subjecting it to control
Histones
Must be able to recognize the startpoint or transcription start site
RNA Polymerase II
Most important and fundamental element of cis-acting elements A. Promoters B. Terminator C. Enhancers D. Silencers E. Insulators F. Response elements
A. Promoters
A DNA sequence just downstream of the coding segment of a gene, which is recognized by RNA polymerase as a signal to stop transcription A. Promoters B. Terminator C. Enhancers D. Silencers E. Insulators F. Response elements
B. Terminator
A regulatory DNA sequence that greatly enhances the transcription of a gene A. Promoters B. Terminator C. Enhancers D. Silencers E. Insulators F. Response elements
C. Enhancers
