Biochemistry review 1 Flashcards
β-pleated sheets are the examples of
Secondary structure
A coiled peptide chain held in place by hydrogen bonding between peptide bonds in the same chain is?
α-helix
Which of the following is not true about secondary protein structure?
The hydrophilic/hydrophobic character of amino acid residues is important to secondary structure
Two chains of amino acids in an insulin molecule are held together by
Disulfide bridges
Hemoglobin is a
Tetramer
Which of the following is an amino acid?
Proline
Number of hydrogen bonds between adenine and thymine?
2
Which ratio is constant for DNA?
a) A + G / T + C
Which of the following statements is not true about RNA?
Thymine is present
Which of the following statements is true?
The bases in nucleotides are attached to a pentose sugar moiety by a glycosidic linkage
What is the composition of nucleoside?
a base + a sugar
What is the composition of nucleotide?
a base + a sugar + phosphate
Group of adjacent nucleotides are joined by
Phosphodiester bond
DNA denaturation is measured by absorbance at
260nm
Which of the following is false about denaturation?
Disruption of phosphodiester linkage
Which of the following nucleotides is not present in DNA?
UMP
Which of the following involves carrying genetic information from DNA for protein synthesis?
m-RNA
The molecule which acts directly on an enzyme to lower its catalytic rate is
Inhibitor
Which of the following enzyme catalyzes the first step of glycolysis?
Hexokinase
What is the general mechanism of an enzyme?
It acts by reducing the activation energy
Which out of the following statements is true about the regulation of metabolic pathway?
Most of the metabolic pathways are regulated
What is the general term used for the anaerobic degradation of glucose to obtain energy?
Fermentation
Whenever the cell’s ATP supply is depleted, which of the following enzyme’s activity is increased?
Phosphofructokinase-1
- Glycolysis converts
Glucose into pyruvate
When glucose is converted to lactate by anaerobic glycolysis, equivalent number of ATPs derived is?
2
Which enzyme is involved in the pathway of synthesis of acetyl-coA?
Pyruvate dehydrogenase
Which of the following is not an important precursor of glucose in animals?
Glucose 6-phosphate
- Gluconeogenesis involves the conversion of
Pyruvate to glucose
What is the main source of glucose carbons for gluconeogenesis?
Alanine
Which of the following are the ketone bodies?
Acetoacetate and Betahydroxy butyrate
The enzyme ‘Thiolase’ catalyzes the conversion of-
2 Acetyl co A to Acetoacetyl co A
In cystic fibrosis, the pancreatic ducts become obstructed by viscous mucus.
Consequently digestion of which of the following substances would be most
Lipids
Insulin promotes which of the following ?
Transport of glucose in to cells
A 15-year-old female has been diagnosed with anorexia nervosa. In this patient breakdown of fatty acids is required to provide energy. Prior to fatty acid oxidation activation of fatty acid takes place in the cytosol. Which of the following is the product of fatty acid activation ?
Fatty acyl Co A
A fatty acid with 14 carbon atoms will undergo how many cycles of beta oxidation
6
An obese, 40- year-old woman, who recently underwent gastric bypass surgery, presents with severe vomiting due to rapid intake of large quantities of food, which must be avoided after gastric bypass surgery. She had successfully lost 10 pounds over the last month after the surgery due to mobilization of fat stores to provide acetyl co A and Energy. When Stearic acid (18 carbon atoms long-chain fatty acid) is oxidized, how many Acetyl co A are produced?
9
A 4 month -old infant presents with a seizure. His mother reports that her infant has been irritable and lethargic over the past several days. The infant is found to have a profoundly low serum glucose and ketone body level. The infant is diagnosed with medium chain acyl co A dehydrogenase deficiency. What is the biochemical basis of infant’s symptoms?
Beta oxidation of fatty acid is impaired
β- oxidation of long chain fatty acids occurs primarily in which of the following locations?
Mitochondria
How many carbons are removed from fatty acyl co A in one turn of β-oxidation spiral ?
2
- Folic acid is important for which of the following processes?
One carbon metabolism
A 20-year-old male presents with hypertension. He has been prescribed a drug that work by inhibiting the synthesis of catecholamines. Which of the following vitamins participates in the synthesis of catecholamines?
Vitamin C
A bone marrow aspirate of a strictly vegetarian female, confirms the suspicion that she has a pernicious anemia because it showed a greater than normal number of red and white blood cell precursors, most of which were larger than normal. What is the cause of pernicious anemia in this patient?
Vitamin B12 deficiency
A 3 –year-old girl has been brought for consultation. She is well below the 5th percentile for both height and weight with multiple rachitic deformities of the skeleton to include severe bowing of the tibias bilaterally, pigeon chest and thickened/widened wrists bilaterally. Which of the following vitamins can be recommended as a part of treatment?
Vitamin D
A 2 –year-old child presented with chronic cough and Bronchitis, growth failure and passage of light-colored, foul-smelling stools. Mother of the child reported that the child was finding it difficult to locate things in the dim light and during night-time. Which of the following vitamins might be deficient in this child?
Vitamin A
Choose the odd one out-
Vitamin C
Which of the following cofactors is correctly matched with the vitamins it is derived from?
TPP- Vitamin B1
Which of the following is not a clinical outcome of niacin deficiency?
Night blindness
A 70-year-smoker presents with weight loss, blood in the sputum, and fatigue. Imaging shows a nodule in his lung that is diagnosed as cancer by biopsy. It has been proposed that reactive oxygen species may induce mutagenesis
and contribute to the initiation of cancer. Which of the following is an antioxidant vitamin?
Folic Acid
A 2-year- old child presents with chronic cough, bronchitis, growth failure, chronic diarrhea and growth failure. A deficiency of which of the following vitamins should be considered?
Vitamin A
Which of the following is the coenzyme form of Thiamine?
TPP (Thiamine pyrophosphate)
