Foundations 1 Week 1 Flashcards
When a cell is engaged in catabolism, what metabolic intermediate is it typically making, and why?
The cell is going to make acetyl-CoA (from either glucose, fatty acid or protein breakdown). Acetyl-CoA which feeds into the first Step of the TCA cycle and then can be made into pretty much anything in a cell!
Lecture: SM 5 The Tricarboxylic Acid Cycle
Objective: 4. Identify the biosynthetic functions of the TCA cycle. (MKS1a)
Which type of DNA repair is most likely to introduce mistakes and why?
A) Base excision repair
B) Nucleotide excision repair
C) Mismatch repair
D) Non-homologous end joining
E) Homologous repair
Correct answer: D) non-homologous end joining – repair of double stranded break which relies on the trimming of the DNA strand and thus can introduce mutations
A) Base excision repair – repair of damaged nitrogen base by DNA removing surrounding nucleotides and replacing using DNA polymerase and ligase.
B) Nucleotide excision repair – similar to base excision, but modification has a helix-distorting effect
C) Mismatch repair – repair of base pairs misincoporated during DNA replication, relies on homologous base pair
E) Homologous repair – repair of double stranded break which can only occur during S and G2 phase during which matching of sister chromatids allows for high fidelity repair
Lecture SM10 DNA Replication and Repair Objective 3. Identify the mechanisms used to repair DNA damage. (MKS1a)
Aminoacyl—tRNA synthetases must be capable of recognizing which of the following?
A. A specific amino acid and the 40S ribosomal subunit
B. A specific amino acid and the 60S ribosomal subunit
C. A specific ribosomal RNA (rRNA) and a specific amino acid
D. A specific tRNA and a specific amino acid
E. A specific tRNA and a specific mRNA codon
Correct Answer: D. A specific tRNA and a specific amino acid
Lecture SM8 Protein Homeostasis
Objective 1. Describe the genetic code and how it is “read” by tRNAs. (MKS1a)
Which of the following molecules is correctly matched with its function?
A) Signal recognition particle (SRP) is an organic compound off of which an oligosaccharide chain is built in the ER
B) BiP is a chaperone protein binds to proteins being translated within the ER and maintains them in a state competent for subsequent folding and oligomerization
C) Calnexin binds to a ribosome protein complex stalling translation
D) Dolinchol phosphate is a calcium binding protein that facilitates glycoprotein folding
Correct answer B) BiP is a chaperone protein binds to proteins being translated within the ER and maintains them in a state competent for subsequent folding and oligomerization
All answers matched correctly:
A) Signal recognition particle (SRP) binds to a ribosome protein complex stalling translation
B) BiP is a chaperone protein binds to proteins being translated within the ER and maintains them in a state competent for subsequent folding and oligomerization
C) Calnexin is a calcium binding protein that facilitates glyprotein folding
D) Dolinchol phosphate is an organic compound off of which an oligosaccharide chain is built in the ER
Lecture: SM 4 Membrane Proteins and the Secretory Pathway
Objective: 1. Describe the events in the folding and modification of vesicular, membrane and secreted proteins in the ER. (MKS1a)
What processing does the pre-mRNA undergo to become mRNA? How do these affect the final mRNA?
1) 5’ capping – protects mRNA from exonucleases
2) removal of introns by spliceosome – can alter final sequence introducing sequence variability
3) poly(A) addition – protects from stabilized against nuclease degradation Lecture
SM9 Transcription and RNA Processing
Objective 5. Describe key events in the processing of different types of RNA transcripts including trimming, splicing, polyadenylation, and base modification. (MKS1a)
The interconnecting bonds that connecting the nucleotides of RNA and DNA are termed:
A) N-glycosidic bonds
B) 3’-5’-phosphodiester linkages
C) Phosphomonoesters
D) 3’-2’-phosphodiester linkages
E) Peptide nucleic acid bonds
F) Hydrogen bonds
Correct answer: B) 3’-5’-phosphodiester linkages
Lecture SM10 DNA Replication and Repair
Objective 1. Describe the mechanism for replication of eukaryotic DNA. (MKS1a)
Increased altitude is associated with decreased oxygen to which the body reacts by increased the depth and rate of breathing. This is an example of [homeostasis or allostasis].
Allostasis
Allostasis: The process of achieving homeostasis through physiological or behavioral change.
Homeostasis maintains stability; allostasis gets the system to a stable state.
SM1 Introduction to the Human Body, and other Musing
Objective 1. Describe homeostasis and allostasis, and their central place in understanding health and disease.
Diabetic cataracts have been linked to the excessive build up of sorbitol in the lens and associated hyperosmotic effects of sorbitol. The difference of rate in which two enzymes leads to the excessive build-up of sorbitol?
A) Fructokinase and sorbitol dehydrogenase
B) Aldolase B and triose kinase
C) Aldose reductase and sorbitol dehydrogenase
D) Aldose reductase and triose kinase
Correct answer: C) Aldose reductase and sorbitol dehydrogenase
In the polyol pathway, glucose is converted by aldose reductase to sorbitol which is then converted to fructose by sorbitol dehydrogenase. In diabetes, there is an increased concentration of glucose which is quickly converted to sorbitol by aldose reductase. However, sorbitol dehydrogenase is slower and therefore unable to keep up with the conversion. Therefore, there is a build-up of sorbitol which is more polar than glucose and fructose and remains stuck within the lens.
Note that you did not have to know the pathophysiology of diabetic cataracts, simply the polyol pathway.
- Fructokinase converts fructose into F-1-P and is mutated in essential fructosuria.
- Aldose B converts F-1-P into either glyceraldehyde or dihydroxyacetone and is mutated in inherited fructose intolerance.
- Triose kinase convers glyceraldehyde into glyceraldehyde-3-P.
Lecture: SM6 Glucose Metabolism
Objectives: 4. Describe how the dietary monosaccharides glucose, fructose and galactose are oxidized to pyruvate to generate ATP. (MKS1a) 5. Identify the synthetic pathways for which intermediates of glycolysis are substrates. (MKS1a)
What would be the molecular and physiologic consequence of carnitine deficiency when glycogen stores are depleted?
Carnitine is used to transport long chain fatty acids into the mitochondria for further break down into acetyl CoA, therefore long chain fatty acids would be unable to enter mitochondria. There would be build-up of long chain fatty acids and decreased ATP production leading to weakness, hypotonia, and hypoketotic hypoglycemia (low blood glucose with low ketone bodies).
Lecture: SM7 Lipid Metabolism
Objective: 1. Describe how fatty acids are activated and oxidized to acetyl CoA. (MKS1a)
In order to provide energy to a reaction ATP will undergo [reduction or oxidation] to become ADP + Pi.
Oxidation.
ATP is a more reduced molecule and therefore is storing energy. ATP is oxidized into ADP + Pi.
SM2 ATP and Energetics
Objectives: 1. Describe the role of ATP as an energy currency. (MKS1a) 2. Describe what occurs in an oxidation-reduction reaction. (MKS1a)
Which of the following sugars can bypass the phosphofructokinase-1 step of glycolysis? What are the implications of this for the cell’s energetics?
A. Glucose
B. Fructose
C. Galactose
D. Maltose
E. Lactose
F. Melibiose
Correct answer B) Fructose
Maltose (2 glucose molecules),
Lactose (galactose + glucose),
Melibiose (diastereomer of lactose—not metabolized by humans)
Phosphofructosekinase-1 is a key enzyme in glycolysis which is regulated by AMP, F-2,6-bisP, ATP, and citrate. F-2,6-bisP is further regulated by insulin/glucagon ration. Therefore, PFK allows the cell to closely regulated glycolysis based on energy requirements. Since, fructose is able to bypass this regulatory step, it is able to ignore energetic requirements and intracellular phosphate depletion and the rapid generation of uric acid due to activation of AMP deaminase, which could damage the cell.
Lecture: SM6 Glucose Metabolism
Objectives: 3. Identify the key enzymes in glycolysis and their regulation. (MKS1a)
Kinesins are different from dyneins in that they:
A) Require ATP for movement
B) Move towards the plus end of microtubules
C) Move towards the minus end of microtubules
D) Binds to actin
Correct answer: B) Move towards the plus end of microtubules
A) All motor proteins require ATP for movement
C) Dyneins move towards the plus end of microtubules
D) Myosin binds to actin
SM3 Cell Organization and Function
Objective 5: Describe how motor proteins move cargo on cytoskeletal networks and organize the cytoplasm. (MKS1a)
Lysine and leucine are purely ketogenic and are unable to be made into glucose, they are not glucogenic. Which compound are these amino acids converted to so they are able to be harvested for energy in the TCA cycle?
A) Oxaloacetate
B) α-ketoglutarate
C) succinyl CoA
D) acetyl CoA
Correct answer: D) acetyl CoA.
As these amino acids are ketogenic, they can be converted into acetyl CoA which can be made into ketone bodies. Here are the other AA-intermediate matchings:
- oxaloacetate: asparagine, aspartate
- α-ketoglutarate: glutamate, proline, arginine, histidine; fumarate: phenylalanine, tyrosine
- succinyl CoA: methionine, valine, isoleucine, threonine
- acetyl CoA: leucine, isoleucine, lysine, tryptophan
Lecture: SM 5 The Tricarboxylic Acid Cycle & SM 6 Glucose Metabolism
Objective:
For SM 5: 6. Describe the steps in the conversion of amino acids to carbon skeletons that can be oxidized in the TCA cycle. (MKS1a)
For SM 6: 7. Describe how carbon skeletons from amino acids are used to synthesize glucose. (MKS1a)
