1.
Which of the following is the mRNA start codon in most cases?
Correct Answer
C. AUG
Explanation
The mRNA start codon in most cases is AUG. The start codon is the sequence of nucleotides that signals the beginning of protein synthesis. AUG codes for the amino acid methionine and is recognized by the ribosome as the starting point for translation. UAA and UGA are stop codons that signal the end of protein synthesis, while AGU is a different codon that codes for the amino acid serine.
2.
Which of the types of RNA is the smallest?
Correct Answer
B. TRNA
Explanation
tRNA, or transfer RNA, is the smallest type of RNA. It is responsible for carrying amino acids to the ribosomes during protein synthesis. Unlike mRNA (messenger RNA) and rRNA (ribosomal RNA), which are larger and have various roles in protein synthesis, tRNA is the smallest and specifically functions to transfer amino acids.
3.
Which of the following is not considered a pyrimidine?
Correct Answer
D. G
Explanation
The question asks for a pyrimidine that is not considered as a pyrimidine. Pyrimidines are a type of nitrogenous base found in DNA and RNA. The options C, T, and U are all pyrimidines, while G is a purine. Therefore, G is not considered a pyrimidine.
4.
Which of the following is paired correctly?
Correct Answer
B. C-G
Explanation
The correct answer is C-G because in DNA, cytosine (C) always pairs with guanine (G) through hydrogen bonding. This pairing is essential for the structure and stability of the DNA double helix.
5.
Which of the following characterizes a Western blot?
Correct Answer
A. Antibody/protein hybridization
Explanation
A Western blot is a laboratory technique used to detect specific proteins in a sample. It involves the separation of proteins by size through gel electrophoresis, followed by their transfer onto a membrane. The membrane is then incubated with antibodies that specifically bind to the target protein. The antibodies are labeled with a detection molecule, such as an enzyme or fluorescent dye, which allows for the visualization of the protein bands on the membrane. Therefore, the correct answer is antibody/protein hybridization, as it accurately characterizes the process of using antibodies to detect proteins in a Western blot.
6.
Which of the following is the approximate prevalence ratio for cystic fibrosis?
Correct Answer
C. 1: 2,000
Explanation
The approximate prevalence ratio for cystic fibrosis is 1: 2,000. This means that for every 2,000 individuals in the population, one is estimated to have cystic fibrosis.
7.
Which of the following divisions of cell growth precedes Mitosis in the cell cycle?
Correct Answer
A. G
Explanation
In the cell cycle, the division of cell growth that precedes Mitosis is the G1 phase. During this phase, the cell grows in size, synthesizes proteins and organelles, and prepares for DNA replication. After the G1 phase, the cell enters the S phase where DNA replication occurs, followed by the G2 phase where the cell continues to grow and prepares for mitosis. Therefore, the correct answer is G.
8.
Down syndrome is directly linked to a genetic abnormality of chromosome?
Correct Answer
B. XXI
Explanation
Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21. This extra genetic material disrupts the normal development and causes the characteristic physical and cognitive features associated with Down syndrome. Therefore, the correct answer is XXI, which represents chromosome 21.
9.
Which of the following is a characteristic of the Hardy-Weinberg law?
Correct Answer
D. Genotype selection does not occur at the locus
Explanation
The Hardy-Weinberg law states that the frequencies of alleles and genotypes in a population will remain constant from generation to generation in the absence of evolutionary influences. This means that genotype selection does not occur at the locus, as there is no selection for or against specific genotypes. The law assumes that the population is large, mating is random, there is no migration, mutation rates are low, and natural selection is not acting on the gene in question.
10.
Which of the following is not a characteristic of Hurler's syndrome?
Correct Answer
C. Spasticity
Explanation
Hurler's syndrome, also known as mucopolysaccharidosis type I, is a rare genetic disorder caused by the deficiency of an enzyme called alpha-L-iduronidase. It is inherited in an autosomal recessive manner, meaning that both parents must carry the mutated gene for the child to be affected. The syndrome is characterized by various symptoms, including delayed mental development, corneal deficits, and skeletal abnormalities. However, spasticity, which refers to increased muscle tone and stiffness, is not typically associated with Hurler's syndrome.
11.
Which of the following is not a characteristic of Krabbe's disease?
Correct Answer
C. Nausea
Explanation
Krabbe's disease is a rare genetic disorder that affects the nervous system. It is characterized by progressive damage to the myelin sheath, which leads to symptoms such as spasticity and optic nerve deficits. Nausea, on the other hand, is not typically associated with Krabbe's disease. Therefore, the correct answer is nausea.
12.
Which of the following is not a characteristic of Fabry's disease?
Correct Answer
C. Profound muscular weakness
Explanation
Fabry's disease is an X-linked disease caused by low levels of alpha-galactosidase A, an enzyme that breaks down a type of fat called globotriaosylceramide. This leads to the accumulation of ceramide trihexoside in various tissues and organs, causing symptoms such as kidney problems, skin rashes, and pain in the hands and feet. However, profound muscular weakness is not a characteristic of Fabry's disease.
13.
Which of the following is not a characteristic of Sickle Cell Anemia?
Correct Answer
B. Autosomal dominant
Explanation
Sickle Cell Anemia is a genetic disorder caused by a mutation in the beta-globin gene, resulting in the production of abnormal hemoglobin. It is characterized by the sickling of red blood cells, leading to various complications. Sickle Cell Anemia is more common in individuals of African descent due to the protective effect it provides against malaria. The condition is inherited in an autosomal recessive manner, meaning that both parents must carry the mutated gene for a child to be affected. Therefore, the statement "Autosomal dominant" is not a characteristic of Sickle Cell Anemia.
14.
Which of the following is not a characteristic of the Southern blot?
Correct Answer
C. Activated by antigen/antibody reactions
Explanation
The Southern blot technique is used to detect specific DNA sequences in a sample. It involves DNA hybridization, which is the process of binding complementary DNA strands together. It also uses a filter and film combination to visualize the DNA bands. However, it does not involve antigen/antibody reactions. Antigen/antibody reactions are typically used in techniques such as the Western blot, which detects specific proteins rather than DNA. Therefore, the characteristic that is not associated with the Southern blot is being activated by antigen/antibody reactions.
15.
Which of the following is not a characteristic of S-adenosyl-methionine?
Correct Answer
B. Considered a rate limiting enzyme of glycolysis
16.
Which of the following is not an activated carrier?
Correct Answer
D. GMP
Explanation
An activated carrier is a molecule that carries energy or chemical groups to be transferred to other molecules in metabolic reactions. ATP (adenosine triphosphate) is a well-known activated carrier that carries energy in cells. SAM (S-adenosylmethionine) is another activated carrier that transfers methyl groups in various reactions. TPP (thiamine pyrophosphate) is an activated carrier of a two-carbon fragment in certain metabolic reactions. GMP (guanosine monophosphate), on the other hand, is not an activated carrier molecule. It is a nucleotide that serves as a building block for RNA and DNA, but it does not carry energy or chemical groups for transfer.
17.
The end product of the TCA cycle produces ____ NADH.
Correct Answer
A. 3
Explanation
The TCA cycle, also known as the citric acid cycle or Krebs cycle, is a series of chemical reactions that occur in the mitochondria of cells. During this cycle, one molecule of glucose is completely oxidized, resulting in the production of several energy-rich molecules, including NADH. NADH is produced three times during the TCA cycle, making it the correct answer.
18.
How many ATP are required to transform pyruvate into glucose?
Correct Answer
B. 6
Explanation
To transform pyruvate into glucose, a process called gluconeogenesis takes place. This process requires 6 molecules of ATP. ATP is used as an energy source for various cellular processes, and in this case, it is needed to drive the reactions involved in converting pyruvate into glucose. Therefore, the correct answer is 6.
19.
Which of the following is not a derivative of the amino acid (Tryptophan)?
Correct Answer
C. Creatine
Explanation
Creatine is not a derivative of the amino acid Tryptophan. Tryptophan is a precursor for the synthesis of both serotonin and melatonin, which are neurotransmitters involved in mood regulation and sleep-wake cycles respectively. Niacin, also known as vitamin B3, can be synthesized from Tryptophan as well. However, creatine is not derived from Tryptophan. Creatine is synthesized from the amino acids glycine, arginine, and methionine in the liver and kidneys.
20.
Pompe's disease is a type ___ glycogen storage disease.
Correct Answer
B. II
Explanation
Pompe's disease is a type II glycogen storage disease. This means that it is caused by a deficiency of the enzyme acid alpha-glucosidase, which is responsible for breaking down glycogen in the lysosomes. Without this enzyme, glycogen accumulates in various tissues, particularly in the muscles, leading to muscle weakness and other symptoms characteristic of Pompe's disease.