1.
Describe Chlamydia Trachomatis
Correct Answer
Causes urethritis in males, cervaviatis in females . Can cause Prostatis and epidymitis in males and Pelvic inflammatory diease in females. Can lead to epotic pregnancy, infertility, and can cause occular infection leading to blindness.
Explanation
Chlamydia Trachomatis is a bacterial infection that can cause urethritis in males and cervicitis in females. In males, it can also lead to prostatitis and epididymitis, while in females it can cause pelvic inflammatory disease. If left untreated, Chlamydia Trachomatis can result in ectopic pregnancy, infertility, and ocular infections that can lead to blindness.
2.
True or false: Mycoplasma are the smallest free living ?
Correct Answer
A. True
Explanation
Mycoplasma are indeed the smallest free-living organisms. They are unique because they lack a cell wall, making them flexible and capable of taking on various shapes. Due to their small size and minimalistic structure, they have a reduced genome and rely on host organisms for many essential nutrients. Mycoplasma can be found in various environments, including soil, water, and the respiratory tracts of animals. Their small size and adaptability allow them to survive and thrive in diverse conditions.
3.
Why is Mycoplasma unstainable ?
Correct Answer
Because they have no peptioglycan in their cell walls.
Explanation
Mycoplasma is unstainable because it lacks peptidoglycan in its cell walls. Peptidoglycan is a substance found in the cell walls of most bacteria that helps retain the stain during the staining process. However, Mycoplasma is a unique type of bacteria that lacks peptidoglycan, making it difficult to stain using traditional staining techniques. This characteristic is one of the reasons why Mycoplasma is challenging to detect and study in the laboratory.
4.
Why are mycobacteria unstainable?
Correct Answer
Waxes do not allow it, must stain with ziehl-neelsen (Z/N) stain that is acid fast.
Explanation
The reason mycobacteria are unstainable is because their cell walls contain waxes that prevent the uptake of most stains. In order to visualize these bacteria, a special staining method called the Ziehl-Neelsen (Z/N) stain is used, which is acid-fast and can penetrate the waxy cell wall. This stain allows the mycobacteria to be stained and observed under a microscope.
5.
Describe Mycobacteria Tuberculosis - primary
Correct Answer
1) Primary Tuberculosis: after inhalation of aeorsol droplets, the M. Tuberculosis colonizes in the lungs and uses macrophages to begin multiplying. Move to the hilar lymph nodes. Can remain dormant for months or even years. During primary infection, some tubercule bacilli espcape lymphatics and blood stream and reach lungs, bones, kidneys where they produce a foci of infection. Primary Complex - complex formed by the local lesion in the lung, draining lymphatics and the reacting(enlarging lymph nodes ) .
Explanation
The primary tuberculosis infection occurs when M. Tuberculosis is inhaled through aerosol droplets and establishes itself in the lungs. It then uses macrophages to multiply and can spread to the hilar lymph nodes. The bacteria can remain dormant for extended periods of time. During the primary infection, some of the tubercle bacilli can escape the lymphatics and bloodstream and reach other organs such as the lungs, bones, and kidneys, where they cause localized infections. The primary complex refers to the combination of the local lung lesion, the draining lymphatics, and the enlarging lymph nodes.
6.
Which of the following describe clostridium?
Correct Answer
D. Can be carried in asymptomatic hosts
Explanation
Clostridium can be carried in asymptomatic hosts, meaning that individuals can have the bacteria in their bodies without showing any symptoms of infection. This is important because asymptomatic carriers can unknowingly spread the bacteria to others who may develop symptoms or become infected. It is worth noting that clostridium is actually an anaerobic gram-positive rod and is able to form spores. Disease from clostridium is not solely due to the host's response, but rather a result of the bacteria's virulence factors and toxins.
7.
Which of the following is a spore forming bacteria that can cause diarrhea in hospital patients?
Correct Answer
D. C. Difficile
Explanation
C. Difficile is a spore-forming bacteria that can cause diarrhea in hospital patients. It is a common cause of healthcare-associated infections, particularly in patients who have been on antibiotics or have weakened immune systems. C. Difficile produces toxins that damage the lining of the colon, leading to symptoms such as diarrhea, abdominal pain, and fever. It can spread easily in healthcare settings and is resistant to many disinfectants, making it difficult to eradicate. Prompt diagnosis and appropriate treatment are essential to prevent complications and further transmission.
8.
A patient on cephalosporins, clindamycin and ampicillin presents with a C. Diff infection. Which of the following are possible contributors to their infection?
Correct Answer
D. All of the above
Explanation
All of the listed options can be possible contributors to the patient's C. Diff infection. The use of cephalosporins, clindamycin, and ampicillin can suppress the normal flora in the patient's gut, which allows C. difficile to overgrow and cause an infection. Additionally, the patient may have been previously colonized by C. difficile, making them more susceptible to infection. Lastly, the acquisition of C. difficile spores after the normal flora has been suppressed can also contribute to the infection.
9.
Which microbe is the smallest?
Correct Answer
A. Virus
Explanation
Viruses are considered the smallest microbes because they are smaller than bacteria, fungi, and parasites. Viruses are microscopic infectious agents that can only replicate inside the cells of living organisms. They consist of genetic material (DNA or RNA) surrounded by a protein coat. Unlike bacteria, fungi, and parasites, viruses are not considered living organisms as they lack cellular structure and cannot carry out metabolic processes on their own. Due to their small size and unique structure, viruses can easily penetrate host cells and hijack their machinery to replicate and spread.
10.
The followings are the First Line of Defence in the body EXCEPT
Correct Answer
A. The production of antibodies by white blood cells
Explanation
The production of antibodies by white blood cells is not considered the first line of defense in the body. The first line of defense includes physical barriers like the skin epidermis, which acts as a protective barrier, and the acid produced in the stomach that helps kill germs. Tears produced by the tear glands also play a role in killing germs. The production of antibodies by white blood cells is part of the second line of defense, which is the immune response that occurs after the initial barrier has been breached.
11.
What is a pathogen?
Correct Answer
B. A disease-causing microbe
Explanation
A pathogen refers to a disease-causing microbe. Pathogens are microorganisms such as bacteria, viruses, fungi, or parasites that can invade the body and cause disease. They can infect various tissues and organs, leading to illness and symptoms. Pathogens can be transmitted through various means such as direct contact, airborne droplets, contaminated food or water, or insect bites. Understanding pathogens is crucial in preventing and treating infectious diseases.
12.
Which type of microorganisms are most pathogens?
Correct Answer
C. Viruses
Explanation
Viruses are considered the most pathogenic microorganisms because they have the ability to invade host cells and replicate inside them, causing various diseases. Unlike bacteria and fungi, viruses lack cellular machinery and can only reproduce by hijacking the host's cellular machinery. This enables viruses to rapidly multiply and spread throughout the body, leading to severe infections. Additionally, viruses can mutate quickly, making it challenging for the immune system to recognize and eliminate them effectively.
13.
Food poisoning may be resulted even the food is well cooked because
Correct Answer
D. Bacteria can produced toxins that can't be destroyed during cooking
Explanation
During the cooking process, bacteria can produce toxins that are resistant to high temperatures. These toxins are harmful and can cause food poisoning even if the food is well cooked. While cooking can kill a significant amount of bacteria, it is not always able to eliminate all of them. Therefore, if the bacteria present in the food produce toxins that are heat-stable, they can remain in the food even after cooking, leading to food poisoning.
14.
Which type of cells is responsible for body defence against infection?
Correct Answer
C. White blood cells
Explanation
White blood cells are responsible for body defense against infection. They are part of the immune system and help to fight off pathogens such as bacteria, viruses, and fungi. White blood cells are able to recognize and destroy these harmful invaders, playing a crucial role in protecting the body from infections and diseases.
15.
Which of the following caused by a virus?
Correct Answer
C. AIDS
Explanation
AIDS is caused by the human immunodeficiency virus (HIV), which is a virus that attacks the immune system. It weakens the immune system, making the body more susceptible to infections and diseases. Malaria, pneumonia, and cholera are caused by parasites, bacteria, and contaminated water respectively, not by viruses. Therefore, the correct answer is AIDS.
16.
One of the main problems with viruses is that they:
Correct Answer
C. Can't be killed by antibiotics
Explanation
Viruses cannot be killed by antibiotics because antibiotics are designed to target and kill bacteria, not viruses. Antibiotics work by interfering with the growth and reproduction of bacteria, but they are ineffective against viruses because viruses are structurally different and have different mechanisms of replication. Viral infections are typically treated with antiviral medications that specifically target the virus or by using supportive care to manage symptoms while the body's immune system fights off the infection.
17.
What is one way that antibiotics work?
Correct Answer
A.
They can stop bacteria from reproducing
Explanation
Antibiotics work by targeting the mechanisms that bacteria use to reproduce. They can inhibit the synthesis of bacterial DNA, RNA, or proteins, preventing the bacteria from replicating and dividing. By stopping bacteria from reproducing, antibiotics can effectively control and eliminate bacterial infections.
18.
The Eloba outbreak in 2014 has killed over 1000 people in Africa. What type of pathogen is Eloba?
Correct Answer
D. Virus
Explanation
Eloba is a virus. This is evident from the fact that it caused an outbreak and resulted in the death of over 1000 people. Viruses are known to cause infectious diseases and can spread rapidly among a population.
19.
What are "Superbugs"?
Correct Answer
C. Bacteria that are resistant to most antibiotics
Explanation
Superbugs are bacteria that have developed resistance to most antibiotics. This means that the usual treatments for bacterial infections are ineffective against them. This resistance can occur naturally or be acquired through genetic mutations or the transfer of resistance genes between bacteria. Superbugs pose a significant threat to public health as they can cause severe and difficult-to-treat infections, leading to increased mortality rates and healthcare costs. Efforts are being made to develop new antibiotics and promote responsible antibiotic use to combat the rise of superbugs.
20.
The following are Agents for Infectious Diseases EXCEPT
Correct Answer
B. Algae
Explanation
Algae are not agents for infectious diseases because they are not capable of causing infections in humans or other organisms. While viruses, bacteria, and fungi are all known to cause infectious diseases, algae are primarily photosynthetic organisms that are more commonly found in aquatic environments. They do not possess the necessary mechanisms to invade and infect host cells, unlike viruses, bacteria, and fungi. Therefore, algae are not considered agents for infectious diseases.
21.
What is the definition of vector?
Correct Answer
D. An organism that transfers a disease from one organism to another organism
Explanation
The correct answer is "An organism that transfers a disease from one organism to another organism." A vector is typically an organism, such as a mosquito or tick, that can carry and transmit a disease-causing pathogen from one host to another. This can lead to the spread of infectious diseases.
22.
What is a Pandamic disease?
Correct Answer
B. The rapid spread of a disease across the world
Explanation
A pandemic disease refers to the rapid spread of a disease across the world. This means that the disease is not limited to a specific country or region but has spread globally, affecting multiple countries and populations. Pandemics often result in widespread illness and can have significant social and economic impacts on a global scale.
23.
The second line of body defence is
Correct Answer
A. Inflammation response
Explanation
The second line of body defense refers to the inflammation response. Inflammation is a natural and protective response of the body to injury or infection. It involves the dilation of blood vessels, increased blood flow, and the release of chemicals to recruit white blood cells to the site of infection or injury. This response helps to isolate and destroy pathogens, remove damaged cells, and initiate the healing process. Inflammation is an essential part of the immune system's defense mechanism and plays a crucial role in fighting against infections.
24.
Which is not a way to prevent infectious disease?
Correct Answer
B. Low fat diet
Explanation
A low fat diet is not a way to prevent infectious diseases. While maintaining a healthy diet is important for overall health, it does not directly prevent the spread of infectious diseases. Vaccination helps the body build immunity against specific pathogens, personal hygiene practices such as handwashing help prevent the transmission of germs, and using disinfectants helps kill or reduce the number of pathogens on surfaces. However, a low fat diet does not have a direct impact on preventing the spread of infectious diseases.
25.
Name the form of nucleic acid that acts as a "messenger" to direct the production of proteins.
Correct Answer
mRNA
Explanation
mRNA, or messenger RNA, is a form of nucleic acid that carries genetic information from the DNA in the nucleus of a cell to the ribosomes in the cytoplasm. It serves as a "messenger" molecule that directs the synthesis of proteins by providing the instructions for the order and arrangement of amino acids. This process, known as protein synthesis or translation, is essential for the functioning and development of living organisms. mRNA plays a crucial role in the central dogma of molecular biology, where genetic information is transcribed from DNA to mRNA and then translated into proteins.
26.
Fill in the gap:Transcription produces an mRNA molecule that is __________ to one strand of DNA.
Correct Answer
Complementary
Explanation
Transcription is the process by which an mRNA molecule is synthesized using a DNA template. During transcription, the mRNA molecule is created in a complementary manner to one of the DNA strands. This means that the mRNA molecule will have a sequence that is complementary to the DNA strand it was transcribed from. Therefore, the correct answer is "complementary."
27.
In RNA, an alternative base replaces DNA's thymine. Name this base.
Correct Answer
uracil
Explanation
In RNA, the base that replaces DNA's thymine is called uracil. Thymine is found in DNA, but in RNA, uracil takes its place. Uracil is one of the four bases that make up RNA, along with adenine, cytosine, and guanine. This substitution allows RNA to perform its functions, such as protein synthesis, without the need for thymine.
28.
Name the sugar in RNA.
Correct Answer
Ribose
Explanation
Ribose is the correct answer because it is a sugar molecule that is found in RNA. RNA, or ribonucleic acid, is a type of nucleic acid that is essential for protein synthesis and gene expression. Ribose is a five-carbon sugar that forms the backbone of RNA molecules, connecting the individual nucleotide units together. It provides the necessary structure and stability for RNA to carry out its functions in the cell.
29.
True or false:DNA is less stable than RNA.
Correct Answer
B. False
Explanation
FALSE: RNA is less stable than DNA, both genetically and chemically.
30.
RNA is chemically less stable than DNA.Why?
Correct Answer
A. It is more reactive than DNA
Explanation
RNA is chemically less stable than DNA because it contains a ribose sugar molecule that has an additional hydroxyl group compared to DNA's deoxyribose sugar. This extra hydroxyl group makes RNA more prone to hydrolysis, which can lead to the degradation of the RNA molecule. Additionally, RNA is typically single-stranded, making it more susceptible to damage from enzymes and other reactive molecules. Overall, these factors contribute to RNA's higher reactivity and lower stability compared to DNA.
31.
What property of the RNA molecule makes it more reactive than DNA?
Correct Answer
A. Its sugar, ribose, has a 2' OH group
Explanation
RNA is more reactive than DNA because its sugar, ribose, has a 2' OH group. This hydroxyl group at the 2' position of ribose makes RNA more susceptible to chemical reactions compared to DNA, which lacks this group. The presence of the 2' OH group increases the reactivity of RNA, allowing it to participate in various enzymatic and chemical processes.
32.
Which of the following reasons are correct for why RNA is genetically less stable than DNA?
Correct Answer(s)
A. Single stranded, so no back-up of genetic information
B. More prone to mutate; cytosine --> uracil cannot be detected and repaired
Explanation
RNA is genetically less stable than DNA because it is single stranded, which means there is no back-up of genetic information. Additionally, RNA is more prone to mutate because the base cytosine can be converted to uracil, which cannot be detected and repaired.
33.
Name the enzyme that synthesises RNA from a template strand of DNA.
Correct Answer(s)
RNA polymerase
Explanation
RNA polymerase is the enzyme responsible for synthesizing RNA from a template strand of DNA. It binds to the DNA template and catalyzes the formation of phosphodiester bonds between nucleotides, resulting in the synthesis of an RNA molecule that is complementary to the DNA template. RNA polymerase plays a crucial role in gene expression by transcribing the genetic information encoded in DNA into RNA, which can then be used as a template for protein synthesis.
34.
In what direction is RNA synthesised?
Correct Answer
A. 5' to 3'
Explanation
RNA is synthesized in the 5' to 3' direction. This means that the RNA molecule is built by adding nucleotides to the 3' end of the growing chain. The 5' end of the RNA molecule is formed first, and as new nucleotides are added, they attach to the 3' end. This directionality is important for the proper functioning of RNA in processes such as transcription and translation.
35.
And so in which direction is the DNA template strand read?
Correct Answer
A. 3' to 5'
Explanation
The DNA template strand is read in the 3' to 5' direction. This means that during DNA replication or transcription, the enzyme responsible for synthesis (such as DNA polymerase or RNA polymerase) moves along the template strand in the 3' to 5' direction, synthesizing the complementary strand in the 5' to 3' direction. This is because DNA and RNA polymerases can only add nucleotides to the 3' end of a growing strand. Therefore, the template strand is read in the opposite direction, from 3' to 5'.
36.
What is the name given to the molecules that line up along the DNA template strand during transcription?
Correct Answer
NTPs
NTP
nucleoside triphosphates
nucleoside triphosphate
Explanation
During transcription, the molecules that line up along the DNA template strand are called nucleoside triphosphates (NTPs). NTPs are the building blocks used by RNA polymerase to synthesize RNA molecules. They are composed of a nitrogenous base (adenine, guanine, cytosine, or uracil), a sugar molecule (ribose), and three phosphate groups. As RNA polymerase moves along the DNA template, it adds complementary NTPs to the growing RNA strand, resulting in the formation of a new RNA molecule that is complementary to the DNA template strand.
37.
Which of the following provides energy for polymerisation of the mRNA strand?
Correct Answer
A. PyropHospHate is lost from NTP, and breakage of pHospHoanhydride bond provides energy for polymerisation
Explanation
During the polymerization of the mRNA strand, energy is required to form the phosphodiester bond between nucleotides. In this process, pyrophosphate (PPi) is lost from the nucleoside triphosphate (NTP) molecule, which releases energy. The energy is then used to break the phosphoanhydride bond, which is present between the phosphate groups in the NTP molecule. This breakage of the phosphoanhydride bond provides the necessary energy for the polymerization reaction to occur.
38.
Fill in the gap: RNA polymerase interacts with other proteins, _____________, when it binds to the promoter.
Correct Answer
transcription factors
Explanation
RNA polymerase is responsible for transcribing DNA into RNA. When it binds to the promoter, it interacts with other proteins called transcription factors. These transcription factors help to initiate and regulate the transcription process by assisting in the binding of RNA polymerase to the promoter region of the DNA. They play a crucial role in determining when and where gene expression occurs.
39.
The ________ is the set of all RNA molecules, depending on cell or cell type, and including mRNA.
Correct Answer
Transcriptome
Explanation
The term "transcriptome" refers to the complete set of RNA molecules present in a cell or a specific cell type, which includes messenger RNA (mRNA) along with other types of RNA. It encompasses all the RNA transcripts that are produced from the DNA in the cell, providing valuable information about gene expression and regulation. The transcriptome is dynamic and can vary depending on the cell's specific needs and environmental conditions.
40.
MRNA must be processed before it leaves the nucleus.Which of the following is true?
Correct Answer
A. The 5' end is "capped" with an atypical nucleotide.
Explanation
mRNA must undergo processing before it leaves the nucleus, and one of the modifications that occur is the addition of a "cap" at the 5' end. This cap consists of an atypical nucleotide called 7-methylguanosine. This cap plays a crucial role in various processes, including protecting the mRNA from degradation, facilitating its export from the nucleus, and promoting translation initiation. Therefore, the correct statement is that the 5' end is "capped" with an atypical nucleotide.
41.
MRNA must be processed before it leaves the nucleus.Which of the following is true?
Correct Answer
A. The 3′ end of the mRNA gets a tail of poly-A nucleotides
Explanation
mRNA must undergo processing before it can leave the nucleus. One of the modifications that occur during this processing is the addition of a tail of poly-A nucleotides to the 3' end of the mRNA molecule. This poly-A tail helps to stabilize the mRNA, protect it from degradation, and facilitate its translation into protein. Therefore, the statement "The 3′ end of the mRNA gets a tail of poly-A nucleotides" is true.
42.
Fill in the gap:Before mRNA leaves the nucleus, it is processed.During this process __________, non-coding sequences, are 'spliced' from the mRNA.
Correct Answer
Introns
Explanation
Before mRNA leaves the nucleus, it undergoes a processing step called splicing. During this process, non-coding sequences known as introns are removed from the mRNA molecule. This ensures that only the coding sequences, known as exons, are present in the mature mRNA molecule, which can then be used as a template for protein synthesis.
43.
What form of RNA performs the splicing reaction of introns from mRNA?
Correct Answer
A. Small nuclear RNAs (snRNAs)
Explanation
Small nuclear RNAs (snRNAs) are responsible for performing the splicing reaction of introns from mRNA. These small RNA molecules are found in the nucleus of eukaryotic cells and are part of the spliceosome, a complex responsible for removing introns and joining exons together in the process of mRNA splicing. SnRNAs recognize specific sequences at the intron-exon boundaries and catalyze the splicing reaction, resulting in the production of mature mRNA molecules that can be translated into proteins. Transfer RNAs (tRNAs) are involved in protein synthesis, small interfering RNAs (siRNAs) and microRNAs (miRNAs) are involved in gene regulation, but they do not perform the splicing reaction of introns from mRNA.
44.
The splicing reaction is primarily performed by small nuclear RNA molecules (snRNAs) that bind to proteins to form small nuclear ribonucleoprotein particles (snRNPs) that form the core of the _______________.
Correct Answer
Spliceosome
Explanation
The splicing reaction is primarily performed by small nuclear RNA molecules (snRNAs) that bind to proteins to form small nuclear ribonucleoprotein particles (snRNPs) that form the core of the spliceosome. The spliceosome is responsible for removing introns and joining together exons in pre-mRNA to generate mature mRNA. It is a complex molecular machinery involved in the process of RNA splicing, which is essential for gene expression and the production of functional proteins.
45.
Pseudomembranous colitis is linked to antibiotic use and which of the following bacteria?
Correct Answer
B. Clostridium
Explanation
Pseudomembranous colitis is a condition characterized by inflammation of the colon, usually caused by the overgrowth of Clostridium difficile bacteria. This bacterium is commonly associated with antibiotic use, as antibiotics can disrupt the normal balance of bacteria in the gut, allowing Clostridium difficile to multiply and cause infection. Therefore, the correct answer is Clostridium.