Answer: a. has a lag period while B cells proliferate and differentiate into plasma cells
Explanation:
When the body comes in contact with foreign antigen for first time it is accompanied by primary immune responses, a lag period occurs in which no antibody is produced but activated B cells are transformed into plasma cells, this is called lag phase. The lag period may be as short as 2-3 days but is sometimes longer.
white blood cells consist of B cells which are formed in the bone marrow. Growing B cell (after first exposure) produces several copies of one type of antigens as a surface antigen receptor. The entire population of B cells has the ability to directly bind to millions of different antigens. If the antibody on a B cell's surface bind to an antigen, the cell will be primed to undergo proliferation and differentiation.
Hence, the correct option is a.
Final answer:
The primary immune response has a lag period while B cells proliferate and differentiate into plasma cells. The secondary immune response occurs more rapidly and is stronger than the primary response.
Explanation:
The primary immune response has a lag period while B cells proliferate and differentiate into plasma cells. During the primary response, some of the cloned B cells are differentiated into memory B cells programmed to respond to subsequent exposures. In contrast, the secondary response occurs more rapidly and forcefully than the primary response, with a decreased lag period and higher levels of antibodies produced.
All scientific investigations are initially founded upon
Answer:
a hypothesis
any scientific investigation must be started on a theory, or hypothesis
Which actions are involved in the immune response
The steps in immune response are;
RecognitionActivationPhagocytosisAntibody productionT cell activationInflammationCytokine releaseMemory formationWhat is immune response?The immune system identifies and recognizes foreign substances, such as pathogens or antigens, that enter the body. Once recognized, the immune system triggers an immune response by activating immune cells, such as white blood cells (leukocytes), to take action against the invader.
Certain immune cells, called phagocytes (e.g., macrophages and neutrophils), engulf and destroy pathogens through a process called phagocytosis. They recognize, engulf, and break down the foreign particles.
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A mutation takes place in a protein-coding gene that changes one codon resulting in a single amino acid replacement. Which type of replacement is least likely to result in a disruption of protein structure and function?
a) a hydrophobic amino acid to a hydrophilic amino acid
b) a polar amino acid to a hydrophobic amino acid
c) an acidic amino acid to a basic amino acid
d) a hydrophilic amino acid to a hydrophobic amino acid
e) a polar amino acid to a polar amino acid
Answer:
The answer is A
Explanation:
The least likely replacement is a polar amino acid to a polar amino acid ( e )
when a mutation takes place in a protein coding gene that changes a single codon ( replacement of an amino acid ) , the amino acid is either replaced with another amino acid with similar properties or it is replaced with an amino acid with different properties.
when a polar amino acid ( hydrophilic ) is replaced by non-polar amino acid ( hydrophobic ) the protein will loses its function ( i.e. the most effect is experienced ) but when a polar amino acid is replaced by another polar amino acid the protein will retain its function ( i.e. the least effect on the protein structure )
Hence the least likely replacement on the protein structure is the replacement of a polar amino acid to a polar amino acid
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An Emergency Medical Responder reports that a male patient, injured while playing football, has bruising to the lumbar area of the back. Based on this statement, the EMT should expect to find bruising in which area?A) Upper back
B) Neck
C) Lower back
D) Buttocks
Answer:
C) Lower back
Explanation:
The lumbar area is located between the chest, the spine and the sacrum. This area corresponds to the lower back and has five vertebrae: L1-L5. According to this, the answer is that based on this statement, the EMT should expect to find bruising in the lower back.
Why are biotechnology companies eager to design genetically modified organisms to express therapeutic proteins, particularly ones that would otherwise have to be isolated from blood products (e.g., human antithrombin) or animal organs (e.g., insulin, originally isolated from pig pancreas)?
Answer:
This is because of reasons of-
safety,
cost-effectiveness and
difficulty in accessibility of needed protein
Explanation:
In order to reduce cost of production for maximal profit, bio.companies usually design their production of therapeutic proteins in possible cost -effective way.This is to ensure maximal yields from production sales. Therefore maximum cost effectiveness is achieved through GMO rather through isolation from blood products or other sources which are expensive and capital intensive to get
In addition safety concerns during production is of ultimost importance to theses companies.Therefore when using of protein from different sources high safety measures are needed to be put in place to achieve best results. whereas GMO comes with little risks.
These companies experiences difficulty in collecting required amount of low abundant protein needed for the synthesis of therapeutic proteins, thus they will rather prefer the design of GMO for abundant supply.
The lateral compartment of the leg contains which muscles?
Peroneus longus, extensor digitorum longus
Abductor hallucis, lumbricals, interossei
Tibialis anterior, extensor hallucis longus,
Peroneus brevis, peroneus longus
Final answer:
The lateral compartment of the leg contains the fibularis longus (peroneus longus) and the fibularis brevis (peroneus brevis), which are responsible for eversion and plantar flexion of the foot and stability of the ankle joint.
Explanation:
The lateral compartment of the leg contains the fibularis longus (peroneus longus) and the fibularis brevis (peroneus brevis). These muscles are responsible for eversion and plantar flexion of the foot, as well as providing stability to the ankle joint.
Sides of the retina are referred to either as nasal or temporal. Nasal is ______ where temporal is ______ A. closest to the forehead; closest to the chin B. closest to the nose; closest to the temples C. closest to the temples; closest to the nose D. closest to the left; closest to the right Reset Selection
Answer: The correct answer to the question is option B
Closest to the Nose; Closest to the temples.
Sides of the retina are referred to as either as nasal or temporal.
Masai is closest to the NOSE while temporal is closest to the TEMPLES.
Explanation: The retina is the innermost layer of the eye,it is made of nerve fibers that transmit impulses to the visual centre in the brain via the optic nerve and the macula lutea which contains light sensitive cells.
The retina is divided into the Nasal retina and the temporal retina.
The nasal retina is the part of the retina that is nearest to the nose.
It is from this nasal side of the retina that the nerve fibers that are going to the opposite side of the cerebrum are projected after they desiccate in the optic chiasma.( X-shaped structure they is formed as a result of crossing if optic nerves in the brain)(crossing over)
Just like the nasal retina,the temporal retina is the part of the retina that is nearest to the temples and it is from this side of the retina that nerve fibres that are going to the same side if the cerebrum are projected after they pass through the optic chiasma. X-shaped structure they is formed as a result of crossing if optic nerves in the brain)(crossing over)
The nasal side of the retina refers to the part closest to the nose, while the temporal side refers to the part closest to the temples (sides of the head). Thus, the correct answer to the question is option Nasal is closest to the nose; Temporal is closest to the temples'.
Explanation:The terms 'nasal' and 'temporal' when referring to the retina indicate their relative positions within the eye. The nasal side of the retina is the part closer to the nose, whereas the temporal side is closer to the temples, that is, the sides of the head. This can be remembered because the term 'nasal' is related to the nose and 'temporal' is related to the temples. Therefore, in the provided options, the correct choice would be B. 'Nasal is closest to the nose; Temporal is closest to the temples'.
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An ecologist hypothesizes that predation by a particular owl species is the major factor controlling the population of a particular rabbit species. If this is the case, which of the following population effects could be expected in this rabbit-owl pair?
A) A fall in the owl population should cause a fall in the rabbit population.
B) A fall in the rabbit population should cause an increase in the owl population.
C) An increase in the diseases in the rabbit population should not change the owl population.
D) An increase in the owl population should cause a fall in the rabbit population.
D) An increase in the owl population should cause a fall in the rabbit population.
Which of the following statements about bryozoans (ectoprocts) is correct? a. Adult bryozoans are sessile, but their larvae make up much of marine plankton. b. Bryozoans are colonial, build reefs, and are related to corals. c. Bryozoans build reefs and have lophophores that extend through a hard exoskeleton. d. Bryozoans are colonial and live amongst mosses.
Answer:
c. Bryozoans build reefs and have lophophores that extend through a hard exoskeleton.
Explanation:
Bryozoans are sessile and colonial, typically settling on hard substrate including sand grains, rocks, and shells, as well as on blades of kelp or other algae, although some species settle on softer sediment.
The correct statement about bryozoans (ectoprocts) is b. Bryozoans are colonial, build reefs, and are related to corals.
To determine the correct statement, let's analyze each option:
a. Adult bryozoans are sessile, but their larvae make up much of marine plankton.
- This statement is true. Bryozoans, also known as ectoprocts, are primarily marine and freshwater sedentary (sessile) animals. Their larvae are indeed planktonic, meaning they drift in the water column as part of the plankton. However, this statement alone does not fully characterize bryozoans.
b. Bryozoans are colonial, build reefs, and are related to corals.
- This statement is correct. Bryozoans are colonial organisms, meaning they live in groups of interconnected individuals. Some species of bryozoans do contribute to reef formation, although they are not the primary reef-builders in modern oceans (that role is primarily filled by corals). Bryozoans are distantly related to corals as both are members of the phylum Lophotrochozoa, but they belong to different classes
c. Bryozoans build reefs and have lophophores that extend through a hard exoskeleton.
- This statement is partially true. While bryozoans do have lophophores (a crown of tentacles surrounding the mouth, used for filter feeding), these structures do not extend through a hard exoskeleton. The lophophore is typically withdrawn into a protective skeletal structure called a zooecium when not feeding. While some bryozoans contribute to reef structures, they do not build reefs in the same way that corals do.
d. Bryozoans are colonial and live amongst mosses.
- This statement is misleading. While the name ""bryozoan"" means ""moss animal,"" this is a historical misnomer. Bryozoans do not live amongst mosses; they are aquatic animals and the ""moss"" in their name likely refers to their colonial, branching appearance that might superficially resemble moss.
Given the information above, option b is the most accurate statement regarding bryozoans. They are indeed colonial, some species contribute to reef structures, and they are related to corals within the Lophotrochozoa phylum.
5. What is the decay product of Uranium-238?
Answer:
Pb-206
Explanation:
A biologist conducts an experiment designed to determine whether a particular type of molecule is transported into cells by simple diffusion, facilitated diffusion, or active transport. He collects the following information: 1) The molecule is very small. 2) The molecule is polar. 3) The molecule can accumulate inside cells even when its concentration inside the cell initially is higher than it is outside the cell. 4) Cells use up more energy when the molecule is present in the environment around the cells than when it is not present. The biologist concludes that the molecule moves across cell membranes by facilitated diffusion. Do you agree with his conclusion?
Answer:
No, this is not a facilitated diffusion but an Active transport process.
Explanation:
This is an active transport process because -
The molecules are moving against the concentration gradient from higher concentration to lower concentration. It is using up energy. The energy is stored in the form of ATP. To move across the concentration gradient ATP is needed.So, we can say that the whole experiment undergoes the Active transport process.
Final answer:
No, the biologist's conclusion is incorrect; the described properties suggest that the molecule is transported across cell membranes by active transport, not facilitated diffusion.
Explanation:
The conclusion drawn by the biologist does not appear to be correct based on the information provided. When considering the information given:
The molecule is polar and small in size.It can accumulate inside cells even when its concentration inside the cell is higher than outside, suggesting movement against the concentration gradient.More energy is used by cells when the molecule is present, indicating an energy-requiring process.These observations are not consistent with facilitated diffusion which is a form of passive transport requiring no energy and occurs down a concentration gradient. Instead, the characteristics described fit active transport, where molecules move against a concentration gradient with the use of energy (ATP).Hypothesize as to why coronaviruses may have glycoproteins in their membranes. What may be the purpose and function of these structures?
Answer:
Viral glycoprotien play important role in virus entry to the cell and virus pathogenicity
They may help viruses avoid the host immune system. Glycoproteins on the surface of the envelope serve to identify and bind to receptor sites on the host's membrane.
Explanation:
Viral glycoproteins play important roles throughout the life cycle of coronaviruses. Viral glycoproteins interact with receptors on the host cell membrane and are required for penetration of the viral genome into cells by fusion of the viral envelope with the plasma membrane or endosomal membrane
The viral glycoproteins participate in assembly of virions, and the intracellular location of viral glycoproteins may determine the location of Coronavirus budding. Viral glycoproteins on the surface of infected cells may permit fusion with adjacent cells, and may make the cell susceptible to immune cytolysis or cell-mediated cytotoxicity, or permit hemadsorption. Epitopes of viral glycoproteins may be recognized by neutralizing, non-neutralizing or hemagglutination-inhibiting antibodies. Thus, elucidation of the structure and functions of Coronavirus glycoproteins is of central importance in understanding the replicative cycle and pathogenesis of coronaviruses.
Final answer:
Glycoproteins in coronavirus membranes serve critical functions in the viral lifecycle, including attachment to host cells, penetration of the cell membrane, replication inside the cell, and release of new virions.
Explanation:
Coronaviruses may have glycoproteins in their membranes to facilitate attachment to host cells. These glycoproteins recognize and bind to viral receptors on the cell surface, allowing the virus to infect specific cell types. For instance, HIV makes use of the CD4 molecule on T lymphocytes. Glycoproteins serve not only for attachment but also play a role in the virus's ability to penetrate the cell membrane, inject its genome, and replicate within the host cell.
Spikes, such as those found on the influenza virus, are extensions of these glycoproteins that allow viruses to both attach and enter a host cell, or detach from it after replication. Known spikes like hemagglutinin (H) and neuraminidase (N) greatly influence the identification and characterization of influenza viruses, denoting specific strains responsible for historical pandemics.
Therefore, these glycoproteins and spikes are vital for the virus's lifecycle, ensuring successful attachment, penetration, replication, and ultimately the release of new virions to infect other cells.
A series of waves with decreasing wavelength labeled A, B, C, D, E, F, G from left to right as wavelength decreases. D is at a place with colored bands crossing the waves with dotted lines down to a colored spectrum from red to blue labeled in nanometers from 700 to 400. Use the drop-down menus to identify the electromagnetic waves. Label A: Label C: Label D: Label G:
Answer:
label A= radio waves, label C= infrared, Label D= visible Light, Label G= gamma rays.
Explanation:
Electromagnetic radiation consists of electromagnetic waves which has frequency of their oscillations. Here label A is radio waves, label C is infrared, Label D is visible Light, Label G is gamma rays.
What are designations of electromagnetic waves?Waves are usually transverse and longitudinal,electromagnetic waves are transverse wave. Electromagnetic spectrum is usually divided into 7 regions, i.e.,
Radio waves.Microwaves.Infrared (IR).Visible light.Ultraviolet (UV) light.X-raysGamma-rays.All these are in order of decreasing wavelength and increasing frequency.
Thus, here label A is radio waves, label C is infrared, Label D is visible Light, Label G is gamma rays.
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The process by which our sensory systems convert stimulus energies into neural messages is called
Answer:
transduction
Explanation:
Sensory transduction is the process by which our sensory systems convert stimulus energies into neural messages which are communicated to our nervous system. It can involve stimuli being compared with or integrated with other stimuli or memories of previous stimuli. Different systems perform sensory transduction, involving either sensory receptors or sensory nerve endings responding to the stimuli.
Explanation:The process by which our sensory systems convert stimulus energies into neural messages is called sensory transduction. This process is carried out by our senses, which convert different types of stimuli into chemical or electrical signals, which are then transmitted to our central or peripheral nervous system. This kind of sensory input involves stimuli being compared with or integrated with other stimuli or memories of previous stimuli.
Just as an example, consider a baseball player at bat. Seeing a baseball pitched does not automatically cause the batter to swing. The trajectory and speed of the ball, and other factors such as the count and the state of the game, are all stimuli that are communicated to the nervous system where they're integrated to generate the specific response - to swing or not swing.
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Humans have changed the selective landscape of Plasmodium, the infectious agent that causes malaria, by developing drugs that kill this parasite. To which drugs have resistant strains of Plasmodium been identified?
Answer:
Doxycycline Drugs in the quinine family ArtemesinsExplanation:
Malaria, a mosquito-borne illness that is life-threatening due to the Plasmodium falciparum parasite, affects more than 200 million people worldwide every year. Several medications are used in the procedure like artemisinin, doxycycline and quinine.
All three drugs artemisinin, doxycycline and quinine carry resistant strains of P. falciparum which prevents malaria.
The ovarian cycle describes the monthly events of a post-pubescent ovary that causes a small number of primary follicles to grow, mature, and ovulate each month. what is the order of the events in one ovarian cycle? drag and drop the events below in the proper sequence.
Answer:
The ovarian cycle regulates endocrine tissue preparation, and egg release in female body.
The first half of the ovarian cycle as the follicular process. Slowly growing rates of FSH and LH are causing follicle development on the ovary surface. This cycle makes the egg primed for ovulation. As the follicles develop they start releasing estrogens and low progesterone levels. Progesterone locks the endometrium in order to help ensure pregnancy. It takes about seven days to travel ovum through the Fallopian tube and to get implanted in uterus. There are 30-60 cells at this point of evolution, called the morula. If there is no pregnancy implantation the lining would be sloughed off. estrogen levels increase after around 5 days, and the menstrual cycle enters the proliferative process. The endometrium starts to regrow, replacing the weakening blood vessels and glands at the end of the last cycle.
Explain how competition limits a population's growth.
Answer: they compete to gather food
Explanation: so therefore the food is in a shortage. So then the weakest/oldest and youngest die out.
How many sex chromosomes does a human haploid cell contain?
Answer:
2
Explanation:
A human haploid cell has two sex chromosomes, a XX (female) and a XY (male)
Who were the main astronomers that named the constellations?
Answer:
In 150 A.D., the Greek scientist Ptolemy published a book, known by its Arabic name, The Almagest, which contained a summary of Greek astronomical knowledge, including a catalog of 1022 stars, with estimates of their brightness, arranged into 48 constellations.
Explanation:
The ancient Greeks and Romans named the constellations based on mythology and cultural beliefs. Astronomers like Giovanni Riccioli and Johann Bayer also contributed to naming features on the Moon and stars in constellations. The brightest stars have names derived from ancient languages.
Explanation:The main astronomers that named the constellations were the ancient Greeks and Romans. They grouped stars into patterns or constellations and gave them names based on mythology and cultural beliefs. The Greeks named sections of the sky in honor of characters in their mythology and then fit the star configurations to animals and people as best they could. The Romans also named the planets after their chief gods.
Later, astronomers like Giovanni Riccioli and Johann Bayer played a role in naming features on the Moon and stars in constellations. Riccioli named lunar craters after famous astronomers, while Bayer assigned Greek letters to the brightest stars in each constellation.
The brightest stars have names that have been passed down from ancient times, with some derived from Greek, Latin, and Arabic languages. Examples include Sirius, which means "the scorched one," and Vega, which means "swooping Eagle."
An action potential releases neurotransmitter from a neuron by opening which channels?
Answer:
Calcium channels.
Explanation:
The arrival of action potential at the presynaptic neuron, cause the opening of Ca+ channels, at the presynpatic neuron membranes. This leads to influx of Ca+ . The latter caused the Acetycholine contained vesicles in the presynaptic neuron to migrate to the tip of the presynaptic neurons, and fused with the neuronal membrane to empty their contents into the synaptic cleft.
Diane wanted to demonstrate which pruning technique was best for controlling the growth of certain types of shrubs. She selected ten shrubs of the same type and randomly assigned each one to receive one of ten different pruning methods. Two weeks after pruning, she measured the regrowth, in inches, of the shrubs; the pruning method that minimized regrowth was recommended as the best method. Which of the following best describes why this is not a well-designed experiment?
A. The shrubs were not randomly selected.
B. Pruning methods were not randomly assigned to shrubs.
C. Each pruning method was used on only one shrub.
D. Each shrub did not receive all ten pruning methods.
E. Only two treatments should be used in an experiment.
Answer:
C. Each pruning method was used on only one shrub.
Explanation:
Reproducibility is one of the most important factors contributing to the reliability of scientific research. The researcher must be able to achieve the same results two to three times. In biological research, this is usually done in the from of triplicates i.e. one experiment is repeated three times. This is done for two reasons:
Producing reproducible resultsRuling out false positives (a negative result that presents as positive due to error) and negatives (a positive result that presents as negative due to error)Triplicates rule out the possibility that the observed change was caused by another factor or through mere chance. Therefore, in the current scenario, each pruning method should have been applied to multiple (at least 3) samples of a shrub.
Food chains demonstrate the flow of ______ and materials through ecosystems
Answer:
energy
Explanation:
what r the pros and cons of renewable energy resources
Answer: Pros: It is abundant, and can be used without interruption, cleaner than fossil fuel. Cons: Can result in air pollution, takes a lot of energy to produce, can be seasonable and competes with food production. Landfill gas, solid waste energy comes from harnessing the decomposition of organic material.
Explanation:
Final answer:
Renewable energy resources have pros, such as sustainability and reduced greenhouse gas emissions, but also cons, including lower efficiency and environmental impacts.
Explanation:
Renewable energy resources have several pros and cons. Some of the pros include:
Renewable resources can be replaced as quickly as they are used, making them sustainable in the long run.Renewable energy sources do not produce greenhouse gas emissions or other air pollutants, reducing the impact on climate change.Renewable energy can provide decentralized control over power, allowing homes and businesses to generate their own electricity without relying on a grid.However, there are also cons to consider:
Renewable energy sources tend to have lower efficiency and higher initial costs compared to fossil fuel technologies.Some renewable energy sources, such as wind and hydro, can have environmental impacts, such as habitat disruption and wildlife disturbance.Availability of suitable land, technological limitations, and competition with other energy technologies can affect the future deployment of renewable energy sources.Which of the following correctly lists the parts of the water cycle?
a Evaporation, condensation, temperature, precipitation, collection
b Condensation, build-up, runoff, precipitation, collection
c Runoff, precipitation, evaporation, melting, condensation
d Evaporation, condensation, precipitation, runoff, collection
Answer:
D
Explanation:
The following sections of the water cycle are correct: Evaporation, condensation, precipitation, runoff, and collection are in Option D as the water cycle is the continuous movement of water in ecosystems.
What are the steps of the water cycle in the ecosystem?The steps of the water cycle consist of evaporation, where water from oceans, lakes, rivers, and even soil is converted into water vapor; condensation, where water vapor rises and cools; and precipitation, where clouds become heavy with water droplets. Then Precipitated waters flow into rivers, and this water can also be collected in man-made structures such as reservoirs and lakes.
Hence, the following sections of the water cycle are correct: Evaporation, condensation, precipitation, runoff, and collection are in Option D as the water cycle is the continuous movement of water in ecosystems.
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Before Alonzo prepares potatoes for dinner, he takes them out of the refrigerator and allows them to sit by a sunny window for about 30 minutes. To prepare them, he peels the potatoes, cuts them into small pieces, and boils them in water. Which of his actions can lead to losses of minerals from the vegetable?
A) Exposing the potatoes to sunlight
B) Cooking the potatoes at high temperatures
C) Storing the potatoes in the refrigerator
D) Using excess water to cook the potatoes
Answer:
D. Using excess water to cook potatoes
Explanation:
Using excess water to cook potatoes can reduce its mineral content.
Answer:
The action that can lead to losses of minerals from the vegetable is D) Using excess water to cook the potatoes.
Explanation:
Due to cooking many losses of minerals for example sodium, potassium, phosphorus, calcium, magnesium, iron, zinc, manganese, copper and various other food materials can be seen.Before and after cooking following changes take place in the mineral content of the vegetables.
(1) The mineral contents of cooked foods in mass cooking were on an average about 60-70 percent of those in raw or uncooked foods.
(2) Cooking losses were particularly high in minerals of vegetables.
(3) Among various cooking methods, loss of mineral was largest in squeezing after boil and in soaking in water after thin slice, followed by parching, frying and stewing.
(4) Cooking losses of minerals in meals cooked in home brought about the similar results as those by the mass cooking procedures.
The measures to prevent cooking loss are
(a) eating the boiled food with the soup
(b) addition of small amount of salt (about 1% NaCl) in boiling
(c) avoidance of too much boiling
(d) selection of a cooking method causing less mineral loss (stewing, frying or parching).
What cell types within bone are responsible for the breakdown of bone tissue to permit reabsorption of calcium?
Answer:
Explanation: Osteoclasts are responsible for resorbing bone matrix and releasing key minerals, including calcium, back into the bloodstream. They are stimulated by parathyroid hormone when blood calcium levels are low.
Explanation:
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What kind of plant life dominates the coniferous forest biome?
Answer:
Gymnosperms (pine trees)
Explanation:
Gymnosperms, or trees that reproduce using cones instead of flowers, are the primary plane life in a coniferous forest.
Some scientists feel that dinosaurs became extinct when a cloud of dust and gas kept sunlight from penetrating the atmosphere for a long period of time. Based on what you now know about photosynthesis, is this a reasonable conclusion? Support your answer.
Answer:
Yes, it is a reasonable conclusion.
Explanation:
The long lasting gas that kept sunlight from penetrating the atmosphere was the key factor that promote a disturbance on the chain food. Without sunlight, plants could not produce their own energy, therefore they could not resist to this environment condition and die. That way, the herbivores could not feed and die as well. Also the carnivore could not survive because their supply of food of herbivores are not alive anymore. This scenario would promote a mass extinction of every dinosaur.
Which of the following statements is false ?
A. Spermatozoa can generally be found in the vagina of a living female three days after sexual intercourse.
B. Semen is unequivocally identified by the presence of spermatozoa.
C. Semen will contain the enzyme p30.
D. The likelihood of finding seminal acid phosphatase in vaginal swabs decreases with time.
Answer:
Option A, Spermatozoa can generally be found in the vagina of a living female after three days
Explanation:
The average life of spermatozoa in the female reproductive tract after ejaculation determines the fertility. Sperm survive for a longer period of time after it reaches the cervix. A spermatozoon (motile sperm) survives for nearly 2.5 hours in the vagina and 48 hours in the oviduct.
However, spermatozoa irrespective of its motility or viability can be found after coital ejaculation in the cervix and vagina even after 12 and 9 days respectively.
Hence, option A is the correct choice of answer
The LPS, or endotoxin, of Neisseria gonorrhoeae is slightly different from most Gram-negative organisms because of the absence of repeating O-antigens; hence, it is called LOS instead of LPS. How could LOS be a major virulence factor for Neisseria gonorrhoeae
Answer:
Neisseria gonorrhoeae the human pathogen that causes the sexually transmitted disease (STD) gonorrhea and is commonly transmitted by exchanging needles through the use of medications or by infected blood products.
LOS is a major virulence factor in Neisseria gonorrhoeae, since LOS causes autolysis during infection and the release of LOS endotoxin damages the host cells is the main cause of most gonorrhoea symptoms including greater frequency or urgency of urination, swelling or redness at the opening of the penis, and swelling or pain in the testicles..