Answer:
There is various kind of proteins found in the human body, which exhibits an array of functions and applications. All the proteins are formed of similar monomers, that is, amino acids, though one can witness different kinds of proteins.
This has been made possible because of the existence of different sequences of amino acids coded for in the DNA. Due to different sequences of amino acids, each protein will fold distinctly and therefore, will exhibit distinct functions inside the body.
Thus, the distinct sequences of amino acids permit for the great diversity of proteins and their functions in the human body even though each of the protein comprises similar kinds of monomers.
Which of the following combinations is most likely to result in digestion?
a. amylase, starch, water, body temperature, testing immediately
b. amylase, starch, water, body temperature, testing after 30 mins
Explain.
Answer:
Option (b).
Explanation:
Digestion may be defined as the process of breakdown of large food particles into smaller substances. The product of digestion must be absorbed in the blood stream.
The digestion process can be seen in laboratory as well. Starch, water, body amylase,temperature, testing after 30 mins result in the process of digestion. The digestion takes time to digest the starch by the enzyme amylase and result of digestion will be seen after 30 minutes rather than testing immediately.
Thus, the correct answer is option (b).
What advantage does crossing over provide for organisms that undergo meiosis over those at only undergo mitosis throughout their life-cycle?
Answer:
Explanation:
Crossing over is a complex mechanism which allows the exchange of the DNA sequence during meiosis.
Crossing over serves many purposes:
1. form genetically different daughter cells from parents.
2. leads to genetic diversity
3. leads to variation in the organism which proves useful.
The crossing over does not take place in the mitosis type of cell division which produces genetically similar daughter cells.
State what you would expect to see in a urine sample that was positive for laxative abuse.
Answer:
Laxatives, which enhance bowel movements, are abused by the individuals who desire to lose weight and are suffering from eating disorders. Laxative abuse leads to extreme symptoms like hypokalemia, diarrhea, abdominal pain, acid-base disturbance, and weight loss.
The majority of the laxatives are captivated by the colon and are discharged in feces or urine as metabolites. In the analysis of urine, the volume of urine gathered within a 24 hours duration is more than two liters. The level of sodium and chlorine reduces in urine and the levels of potassium will enhance in the urine.
A change in electrolyte balance and changes in acid-base results, hypokalemia is the clinical characteristic of laxative abuse. The pH of urine will decline on the basis of the extremity of the abuse. The levels of creatinine will increase, and one can witness elevation in the secretion of renin and aldosterone because of the loss of fluid.
Infants between the ages of six and 12 months are especially at high risk for contracting measles because they are too young to receive the vaccine. Infants are often protected until they are about 6- months-old by maternal antibody. Their mothers either had measles, or were vaccinated against it, before they became pregnant, but as these babies get older, that protection fades. Which of the following is the maternal antibody that protects infants for the first six months of life?
a. IgA
b. IgD
c. IgE
d. IgG
e. IgM
Answer:
The correct answer is d. IgG
Explanation:
During pregnancy the fetus is attached to the mother body by placenta and IgG is the only antibody which can cross the placenta and reach the fetus. This antibody is very important for an infant to get protection from infections.
Measles is a viral disease that usually infects infants who are not vaccinated against it. Until the vaccination is done the infant is protected by the passive immunity given by his mother through passing the IgG antibody.
This maternal antibody is capable of protecting infants for the first six months of life after which vaccination is required to protect the infant from measles.
What is an example of a cell that has specialized domains of plasma membrane?
Answer:
Epithelial cell
Explanation:
A typical epithelial cell is characterized by the presence of special domains of the plasma membrane. An epithelial cell has an apical domain and a basolateral domain.
The apical domain of the epithelial cells is present towards the lumen of the organ while its basolateral domain covers the rest part of the cell.
The two domains differ from each other structurally and perform specific functions. Specialized appendages such as cilia are mostly present in the apical domain of the epithelial cells.
The specific distribution of proteins and lipids is maintained by tight junctions that do not allow the passage of substances between the two domains.
The respiratory system branches like the circulatory. Oxygen and carbon dioxide diffuse between the end of these branches and the bloodstream. What are the ends of those branches called?
What is the purpose of the sphincters where the arterioles branch into the capillary beds?
A. To slow down blood flow so the capillaries don't burst under pressure
B. To block blood from coming back out of the capillary bed too quickly to allow for more complete diffusion of oxygen
C. To control blood flow to different areas of the body depending on activities
D. To speed up blood flow into the capillary bed for faster oxygen exchange
E. They remove carbon dioxide from blood passing through.
Answer:
1. Ends of the respiratory branches are called alveoli.
2. C. To control blood flow to different areas of the body depending on activities
Explanation:
1. The trachea divides into left and right primary bronchi which in turn divide multiple times upon entering the lungs and make the bronchial tree.
The final branches of the bronchial tree are the terminal bronchioles that lead to alveoli. The alveoli are the balloon-shaped structures and serve as the site of gas exchange between the blood and inhaled air.
2. The opening and closing of sphincters of capillary beds regulate the direction of blood flow. The opening of sphincters allows the blood to flow into associated branches of capillary beds while closed sphincters direct the blood from arterioles to venules via thoroughfare channel.
This local change in blood flow is responsible for the autoregulation of blood flow to different tissues to match their respective metabolic demands. For example, during physical activity, more blood is directed to skeletal and cardiac muscles.
Escherichia coli cells are about 2.85 μm long and 0.650 μm in diameter. i) How many E. coli cells laid end to end would fit across a pinhead of diameter 0.5 mm? Number of cells = cells ii) Calculate the volume of an E. coli cell, assuming the cell to be cylindrical in shape. The volume of a cylinder is: Cell volume = m3 iii) Calculate the surface area and surface area to volume ratio of an E. coli cell. The surface area of a cylinder is: Surface area = m2 Surface area:Volume = m-1
Answer:
i) 769 E. coli cells should be laid end to end would fit across a pinhead of diameter 0.5 mm.
ii) [tex]4.1466\times 10^{-18} m^3[/tex] is the volume of an E. coli cell.
iii) The surface area of E coli cell is [tex]1.8578\times 10^{-11} m^2[/tex] and surface area to volume ratio of an E. coli cell is [tex]4,480,297.110 m^{-1}[/tex].
Explanation:
Diameter of the Escherichia coli cell ,d= 2.85 μm = 0.00285 mm
1 μm = 0.001 mm
Length of the Escherichia coli cell ,h= 0.650 μm = 0.000650 mm
Let the number of Escherichia coli cell laid end to end to total length of 0.5 mm be x
[tex]x\times h =0.5 mm[/tex]
[tex]x=\frac{0.5 mm}{0.000650 mm}=769.23\approx 769 [/tex]
769 E. coli cells should be laid end to end would fit across a pinhead of diameter 0.5 mm.
Radius of the Escherichia coli cell r = d/2 = [tex]\frac{0.00285 mm}{2}=0.001425 mm[/tex]
Length of the Escherichia coli cell ,h = 0.000650 mm
Volume of the cylinder = [tex]\pi r^2h[/tex]
Volume of the E coli cell: V
[tex]V=3.14\times (0.001425 mm)^2\times 0.000650 mm[/tex]
[tex]V=4.1466\times 10^{-9} mm^3=4.1466\times 10^{-18} m^3[/tex]
[tex]1 mm^3=10^{-9} m^3[/tex]
Total surface area of cylinder :[tex]2\pi r (r+h)[/tex]
Area of the E coli cell: A
[tex]A=2\times 3.14\times 0.001425 mm\times (0.001425 mm+0.000650 mm)[/tex]
[tex]A=1.8578\times 10^{-5} mm^2=1.8578\times 10^{-11} m^2[/tex]
[tex]1 mm^2=10^{-6} m^2[/tex]
Surface area to volume ratio of an E. coli cell:
[tex]\frac{A}{V}=\frac{1.8578\times 10^{-11} m^2}{4.1466\times 10^{-18} m^3}[/tex]
[tex]=4,480,297.110 m^{-1}[/tex]
Approximately 175 E. coli cells would fit across a pinhead. An individual cell has a volume of approximately 0.971 μm³, a surface area of approximately 5.77 μm², and a surface area to volume ratio of approximately 5.95 m-1.
Explanation:Let's tackle these calculations one at a time:
i) Number of E. coli cells that can fit on a pinhead
To answer this, we need to convert the pinhead's diameter from millimeters (0.5 mm) to micrometers (500 µm) because the length of an E. coli cell is given in micrometers (2.85 µm). If we divide the diameter of the pinhead by the length of the E. coli cell, it will give us the number of cells that can fit across a pinhead. Therefore: 500 µm / 2.85 µm = approximately 175 cells.
ii) Volume of an E. coli cell
Given the E. coli cell can be represented as a cylinder, the formula for the volume of a cylinder is V=πr²h. The radius (r) is the diameter divided by 2, and the height (h) is the length of the cell. Calculating the volume, we get: V = π * (0.325 µm)² * 2.85 µm = approximately 0.971 µm³.
iii) Surface Area and Surface Area to Volume Ratio of an E. coli cell
For a cylinder, the Surface Area(A) = 2πrh + 2πr². Substituting the values: A = 2π*0.325 µm * 2.85 µm + 2π*(0.325 µm)² = approximately 5.77 µm². Finally, the ratio of surface area to volume is 5.77 µm² / 0.971 µm³ = approximately 5.95 m-1.
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Why do women's rights matter when it comes to controlling population growth?
A. Men always want more children than women do, and if women have no power, they don't get a choice.
B. Women with an education and career won't have children.
C. Empowering women gives them control over their own reproduction and they typically will chose to postpone having children.
D. Women generally make the major family decisions.
E. There is no way for men to control their own reproduction.
Answer:
The correct answer is option C.
Explanation:
Empowering women provides them with the power to decide over their own reproduction and they usually should have the choice to postpone having children. All women should possess the right to autonomy and choice of reproduction.
Women should possess the right and social accountability to decide about when and how to have children and should possess the right to decide about how many to have, no women can be forced to bear a child or should be inhibited from doing so against her desire.
Which of the following is not an observation or inference on which natural selection is based?
a. There is heritable variation among individuals.
b. Poorly adapted individuals never produce offspring.
c. Species produce more offspring than the environment can support.
d. Only a fraction of an individual’s offspring may survive.
Answer: B. Poorly adapted individuals never produce offspring
Explanation:
Natural selection is a theory that states organisms adapts to its environment due to differences in their phenotypes. So, individuals with favorable traits are more likely to survive and reproduce. It is a key mechanism of evolution, which is the change in traits of a population over generations.
Populations respond to natural selection if they contain heritable variation among them, wich means that individuals differ in the traits they transmit to their offspring.
Because of the environmental selection pressures, individuals produce more offspring than their environment can support. The pressure determines which individuals will survive and reproduce, while others will die because of predation or diseases. So, natural selection is based on the observations of adapted individuals.
Answer:
i think it is b but i ill let you know since im taking the test rn
Explanation:
k i took the test and re edited this it is b poorly adapted one so yeah have a great day
How does ADH work and what does it do?
A. It binds to the collecting tubules in the kidney, opening pores to allow water to flow back out of the kidney into the blood.
B. It binds to blood cells, making them more porous to water so it more easily diffuses back into them and is not lost in urine filtration.
C. It binds to water molecules, making them too large to diffuse out of the blood stream, retaining water when the body needs it.
D. It binds to nerve cells in hypothalamus, signaling that the body is dehydrated and should retain water.
E. It binds to the kidney tubules, making them less porous to water so less water filters out.
Answer:
The correct answer will be option-A.
Explanation:
ADH or anti-diuretic hormone is a chemical messenger produced by the hypothalamus in response to the water level in the blood, maintain blood pressure.
ADH is released in response to the osmolarity of the blood that is a low amount of water which is perceived by the osmorecpetors in neurons. The low level of water leads to the production of ADH from neurons which binds to the ADH receptors in the collecting tubules of the kidneys.
They allow insertion of aquaporins-2 in the membrane which allow re-absorption of the water to maintain the water level of the body.
Thus, option-A is the correct answer.
A patient is admitted to hospital with a suspected bacterial illness. Describe two immunological techniques that may be used in diagnosing the patient.
Answer:
For the diagnosis of patients having bacterial infection, many immunological tests can be performed by the doctor's like agglutination test and enzyme immunoassays.
Agglutination test: This test confirms the bacterial infection based on antigen-antibody interaction. In this test, patient serum is taken which contains antibody, and latex beads with attached specific antigens are added into it. Agglutination of blood serum confirms the infection of that bacteria whose antigen is used in the test.
Enzyme immunoassays: In this test, the antibody is used which has attached enzyme. This antibody binds to the antigen and the enzyme converts some substrate into a product which have fluorescence. Higher the fluorescence higher is the amount of antigen.
What would happen to the hormone levels in a man's bloodstream if his hypothalamus continuously produces releasing hormones?
a. LH and FSH levels would be low
b. Testosterone would be low
c. LH levels would be high and FSH levels would be low
d. FSH levels would be high and LH levels would be low
e. LH, FSH and testosterone levels would be high
Answer:
e. LH, FSH and testosterone levels would be high
Explanation:
Releasing hormones produced by the hypothalamus stimulate the anterior pituitary gland to release the tropic hormones which in turn stimulate the release of hormones from other glands.
The gonadotropin-releasing hormone produced by the hypothalamus makes anterior pituitary to release gonadotropins (LH and FSH).
The LH stimulates the Leydig cells of testes to release the androgens (testosterone). Therefore, continuous release of releasing hormone from the hypothalamus in a male would increase the LH, FSH and testosterone levels.
If a man's hypothalamus continuously produces releasing hormones, it would lead to high levels of LH, FSH, and testosterone in the bloodstream owing to a successive chain of hormonal stimulation leading up to increased testosterone production in the testes.
Explanation:The hypothalamus is a small region in the brain that plays a crucial role in many important functions, including sending signals to the pituitary gland to release hormones into the bloodstream. When the hypothalamus continuously produces releasing hormones, it stimulates the pituitary gland to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These hormones, in turn, stimulate the testes to produce more testosterone. Thus, the answer is e. LH, FSH, and testosterone levels would be high.
Here's a breakdown of this process:
The hypothalamus produces gonadotropin-releasing hormone (GnRH).GnRH signals the pituitary gland to produce and release LH and FSH.LH and FSH travel via the bloodstream to the testes.LH prompts the testes to produce and secrete testosterone, while FSH is involved in sperm development.The increased levels of these hormones in the bloodstream then lead to the various effects on the body and behavior.Learn more about Hypothalamic-pituitary-gonadal axis here:https://brainly.com/question/29869336
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What
is the only amino acid with a substituted alpha amino group?the
presence of this amino acid influences protein folding byforcing a
bend in the chain- draw its structure.
Answer:
Proline
Explanation:
Proline's unique characteristic it's that it is the only amino acid where the side chain is connected to the backbone twice forming a nitrogen-containing ring, this means it has a substituted alpha-amino group. This characteristic is important to the structure of proteins, because, contrary to glycin which adopts many main chain conformations, proline if most commonly found in tight turns because of its rigidity.
Hope you find this information useful! Good luck!
According to the phylogeny presented in this chapter, which protists are in the same eukaryotic supergroup as land plants?
a. green algae
b. dinoflagellates
c. red algae
d. both a and c
Answer: d. both a and c
Explanation:
Green algae are present in the most diverse environments. The vast majority of species, approximately 90%, are freshwater, with a cosmopolitan distribution, that is, they have a wide distribution on the planet. It is the predominant group of freshwater plankton. BASIC CHARACTERISTICS: Eukaryotic, Chlorophyll a and b, Xanthophylls (mainly lutein) and Carotenes (mainly β-carotene), Reserve: starch, Cell wall: mainly cellulose, Presence of flagella at some stage of the life cycle.
Red algae: Cell wall - consists basically of two parts, one internal and rigid, formed by cellulose microfibrils (most red algae), and the other outer, mucilaginous, formed by galactan polymers, such as agar and carrageenans. Certain groups of red algae have calcium carbonate deposition on the wall, giving the stalk great rigidity. This deposition may be in the form of aragonite or calcite. BASIC CHARACTERISTICS: Eukaryotic, Chlorophyll a and Phycobiliproteins (b, re-phycoerythrin, allophycocyanin and echo-cytocyanin), Xanthophylls (zeaxanthin, lutein, etc.) and carotenes (mainly β-carotene), Reserve: Cellular starch: cellulose, agar and carrageenan, Absence of flagella at all stages of life, including gametes and spores.
What is the nature of "second signal molecules" in signaling pathways?
Answer:
The target receptor is expressed in the membrane, the activity of the receptor can instigate the production of small molecules known as the secondary messengers that coordinate and initiate the intracellular signaling pathways. For example, cyclic AMP is a secondary signal molecule.
When the signal molecules stimulate the receptor, the signal is carried into the cell generally by means of secondary messengers.
Second signal molecules, also known as second messengers, are crucial components of cell signaling pathways. They relay the signal from the cell surface receptor to the interior of the cell, helping to propagate or even amplify the signal for a larger cellular response. Examples include cyclic AMP, inositol trisphosphate, and calcium ions.
Explanation:The nature of "second signal molecules" in signaling pathways refers to a significant part of cell communication. These molecules are often termed second messengers because they relay the signal from the receptor on the cell surface, which is first to identify the signaling molecule, to the interior of the cell. The function of these intermediates is to propagate the signal and sometimes amplify the signal to produce a larger cellular response. Biologically essential second messengers include cyclic AMP (cAMP), inositol trisphosphate (IP3), and calcium ions.
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Describe how the population of the Earth increase if the number of children being born is less?
Answer:
As this ratio of land and man was given by demographer Thomas Malthus who said population on grew in an arithmetic and earth production in a geometric fashion.
Explanation:
The population or the production capacity of the earth will double and increase as long as it's kept stable i.e no interference from the outside world or human world. Even when there are lower birth and population is still decreasing the earth still will produce less as comparatively due to the slow growth of resources. This population may increase due to the number of medical aid facilities provided or may increase due to the population reaches its maturity and gets fixed or stabilized. Population and growth in resource distribution are always linked to the demographic changes in the population distribution around the world. \As the country of Africa has large scale childbirth and is next after Asia in terms of the population even after several years when its population stabilizes there still going to be pressure on the natural resources as these are finite in numbers.Explain how the ears of a human help control balance.
Answer:
Human ear is not only responsible for hearing by also control balance.
Human ear has three sections the outer; middle; and inner ear.
The outer ear consist of pinna and ear lobe, middle ear consist of three tiny bones the malleus, incus and stapes, and inner ear contains cochlea and the vestibular system.
The inner ear carry vestibular system which consist of three semicircular canals, saccule and utricle, responsible for maintaining balance.
The outer ear collects sound waves from outside and guide it to middle ear, and the middle ear changes the sound waves into vibrations and pass it to inner ear. the inner ear utilizes vibrations and send it to nerve impulses. The semicircular canals in the inner ear contains hair cells and fluid and hair cells. When anyone moves their head the fluid in semicircular canals moves along. the motion is then detected by hair cells, which are then send nerve impulses to the brain and functions in maintaining balance.
Answer:
The semicircular canals of the inner ear help you with balance. When you move your head, fluid inside the semicircular canals moves as well. This movement of the fluid moves the hairs of the canals, creating nerve impulses that travel up to your brain and let it know that your head is off balance.
Explanation:
Gene expression in eukaryotes can be regulated at many different levels. List the different levels of regulation, and explain what each means.
Answer:
Transcription, mRNA (processing, transport, localization and stability), translation.
Explanation:
Transcription is regulated in two levels, though chromatin regulation (methylation and acetylation) to loose or increase histone's affinity to DNA and through cis and trans elements such as promoters, enhancers, and silencers (cis) to active/deactivate and RNA polymerase and transcription factors and co-factors (trans).mRNA can be regulated using poly-A tails or 5'-caps to shorten or give them more time before they degrade, it could also be spliced to eliminate introns. In the translation stage, the regulation occurs during the initiation through a scanning procedure that ensures the 40s ribosomal subunit bind correctly to the untranslated portion of RNAHope this information is useful to you!
Systems biology is mainly an attempt to
a. analyze genomes from different species.
b. simplify complex problems by reducing the system into smaller, less complex units.
c. understand the behaviour of entire biological systems by studing interactions among its component parts.
d. build high-throughout machines for the paid acquistion for biological data.
The correct answer is C. Understand the behavior of entire biological systems by studying interactions among its component parts.
Explanation:
Systems biology refer to a field of study that aims at understanding complex biological systems or network of biological factors and organizations using a holistic approach, which means systems are analyzed according to its components from different perspectives. Due to this, systems biology is widely used to understand the way biological system work and the ways these are affected if one of their component parts changes. According to this, the statement that shows the purpose of systems biology is "Understand the behavior of entire biological systems by studying interactions among its component parts".
Systems biology is a field that aims to understand the behavior of entire biological systems by studying the interactions among its components, integrating a variety of biological data for a more comprehensive understanding.
Explanation:Systems biology is an interdisciplinary field that focuses on understanding the behavior of entire biological systems through the study of interactions among its component parts, rather than studying components individually. Therefore, the best answer to your question would be:
c. understand the behaviour of entire biological systems by studying interactions among its component parts.This approach integrates a wide range of biological data, including genomic, proteomic, and metabolomic, to develop a more comprehensive understanding of complex biological processes and systems.
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A sex linked trait can be defined by which genotypes. Choose all which apply.
a. Coded for on the X and Y chromosomes
b. Coded for on the X but not Y chromosome
c. Coded for on the Y but not X chromosom
d. a dominant allele on any chromosome
Answer:
a. Coded for on the X and Y chromosomes
b. Coded for on the X but not Y chromosome
c. Coded for on the Y but not X chromosome
Explanation:
The X and Y chromosomes are the sex chromosomes as they are involved in sex determination. All the genes that are present on the X and Y chromosomes are inherited along with these chromosomes and therefore, exhibit sex-linked inheritance.
X and Y chromosomes share a homologous region. Therefore, the sex-linked genes are defined as the ones present on both X and Y chromosomes as well as the ones that are present on either X or Y chromosomes.
For example, the gene for hemophilia is present on the X chromosome; but not on the Y chromosome. The SRY gene is present only on the Y chromosome.
In which step of the light independent reaction is G3P producod?
a. CO2 production
b. CO2 reduction
c. CO2 fixation
d. Regeneration of RuBP
Answer:
The correct answer will be option-B.
Explanation:
Photosynthesis process takes place in two phases: light-dependent reaction and light-independent reaction.
The light-independent reaction takes place in the fluid-filled space called stroma of a chloroplast and is involved in the formation of glucose molecules. The light-independent reactions take place in cycles and are known as the Calvin cycle.
Calvin cycle proceeds in three phases: carboxylation or carbon fixation, reduction and regeneration. During reduction, the ATP and NADPH provides energy and hydrogen atom to the 3-PGA which gets converted to glyceraldehyde-3-phosphate (G3P).
Thus, Option-C is the correct answer.
In DNA, which base is complementary to guanine?
a. andenine
b. thymine
c. cytosine
d. guanine
Answer:
Guanine is complementary to Cytosine.
Explanation:
The DNA molecule is made up of different components one of them is pairing of nitrogenous bases. The nitrogenous bases are the A, G, C, T. The A , G are the purine and C, T is the pyrimidine.
The A pairs with T by double hydrogen bond, and C pairs with G by a triple hydrogen bond. Thus the helix is arranged in antiparallel order.
The pairing of nitrogenous bases obeys Chargaff's rule. According to this rule, the combination of adenine and thymine is approximately equivalent to the combination of guanine and cytosine.
If the DNA bases do not obey this rule then the helical structure can't be possible. The pairing of purine, purine, and pyrimidine, pyrimidine results too short and too broad helix. Thus proper order of the helix can't be possible.
This is the very reason A double bonds with T and C triple bonds with G.
Answer:
cytosine
Explanation:
Organisms that live in virtually every environment on Earth belong to the Domain Archaea.
a. True
b. False
Answer:
False
Explanation:
The organisms in Domains Bacteria and Archaea are able to thrive in every possible environment present on the earth. They are found in oceans, air, fresh water, soil, inside the body of living beings, hot water springs and even in hydrothermal vents.
Some of these organisms can thrive in the absence of oxygen as they perform anaerobic metabolism. For example, the enteric bacteria are anaerobic as oxygen is not available to them.
The evolution of unique ability to withstand the extremes of the conditions allows the archaeans to thrive under extreme climatic conditions. It includes halophiles, thermophiles, etc.
Explain how regulation of gene expression can alter gene function.
Answer:
Explanation:
The genetic information present in all cells can be compared to a book of blueprints prepared for the construction of a large, multipurpose building.
-At different times, all of the blueprints will be needed, but only a small subset is consulted during the work on a particular floor or room.
-Similarly in the case of cells all the necessary genetic information is present but but only a subset of genes is expressed in any particular cell.
Regulation of gene expression alters the gene function in many ways.
For example in prokaryotes-
The lac operon is an inducible operon, in which the presence of a key metabolic substance which is lactose in this case, initiates transcription of the operon, allowing synthesis of the proteins encoded by the structural genes.
In case of repressor operon: Transcription of the structural genes is controlled by a repressor protein that is synthesized by a regulatory gene, which is also part of the operon. It binds to the operon and blocks the movement of Rna polymerase.
All of the following statements regarding the pathogens that cause tetanus, anthrax, and botulism are correct except:
(If all of the statements are correct, choose the final answer.
a. all three pathogens are soil-bacteria.
b. all three pathogens are obligate anaerobes.
c. all three pathogens produce endospores.
d. all three pathogens produce exotoxins
e. all of the above are true for tetanus, anthrax, and botulism
Answer:
b. all three pathogens are obligate anaerobes.
Explanation:
Tetanus is caused by an exotoxin produced by the bacterium Clostridium tetani, which is normally found in the soil, although it may be present in the intestines of mammals. It is an anoxic and spore-forming bacteria. It enters the body through wounds or deep punctures, finding in the wound the anoxic conditions to germinate its spores, producing its potent toxin.
Anthrax is caused by the bacterium Bacillus anthracis, which is a stationary and endospore-forming bacteria that is resistant to high temperatures and chemicals. It is a strictly aerobic bacterium and can be found naturally in the soil. Both animals and humans can breathe or ingest spores of this bacterium by consuming meat or contaminated water. When spores get into the body, their turn into active cells and produce exotoxins
Botulism is caused by the pathogen Clostridium botulinum, a strict anaerobic bacillus, producing endospores and 8 different types of toxins. Being a soil-borne bacterium, it usually appears in the food of animal and vegetable origin.
Mammals are diphyodont which refers to the fact that
a. in adulthood, the post canine teeth can be replaced twice
b. they have a variety of tooth shapes that allow for them to process a wider variety of foods.
c. adults only have two types of teeth and so can process food differently in the front of the mouth and the back of the mouth
d. they have two successive sets of teeth including milk teeth and permanent adult teeth
e. they have a set number of incisors, premolars, and molars
The correct answer is D. They have two successive sets of teeth including milk teeth and permanent adult teeth
Explanation:
In biology, a diphyodont is an animal that has two different sets of teeth, this often means the animal has a set of baby teeth that are later replaced by permanent teeth, this occurs in most mammals including humans. Additionally, diphyodont differ from other types of animals that have either only one set of teeth (monophyodonts), for example, toothed whales or change their teeth permanently (polyphyodont), for example, crocodiles. Thus, mammals are diphyodont because "they have two successive sets of teeth including milk teeth and permanent adult teeth".
Autotrophic means organisms __________
a. do not produce light
b. produce their own food
c. do not produce their food
d. produce light energy using food
Answer:D
Explanation:
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
a. NADPH -> O2 -> CO2
b. H2O ->S NADPH -> Calvin cycle
c. H2O -> photosystem I -> photosystem II
d. NADPH -> electron transport chain -> O2
Answer: b. H2O ->S NADPH -> Calvin cycle
Explanation:
Photosynthesis can be compartmentalized into two phases: one that depends directly on the light - photochemical phase and one that does not depend on the light, called chemical phase.
The first uses H2O to produce ATP and a reduced electron carrier (NADPH + H +), the second uses ATP, NADPH + H + and CO2 to produce sugar. In the photochemical phase, light energy is used to produce ATP from ADP + Pi, through a set of reactions mediated by groups of molecules - the photosystems - in a cycle called photophosphorylation.
There are two types of photophosphorylation: one non-cyclic that produces NADPH and ATP and one cyclic that produces only ATP. In the chemical phase, which is not directly dependent on light, non-cyclic photophosphorylation products - NADPH and ATP - and CO2 are used to produce glucose, in the so-called Calvin-Benson cycle. Although it is also called the dark phase, it is not independent of light, since for the enzyme responsible for fixing CO2, RuBisCo, requires light to be reduced and to be in its active state.
Mendel's second law is the Law of Independent Assortment. According to that law and according to other facts that Mendel discovered, what statement or statements are true in the following list?
a. genes behave like fluids rather than like separate particles
b. genes behave like separate particles rather than like fluids
c. the alleles of the different genes separate independently of one another during meiosis
d. both a. and c. are correct
e. both b. and c. are correct
Answer:
Option (c).
Explanation:
The Mendel's give the two most important laws to explain the transmission of the characters in the organism. Mendel is known as father of genetics and explained his work on the pea plant Pisum sativum.
The Mendel's law of independent assortment explains that in the combination of different genes the alleles of the genes separate or assort independently to one another during the meiosis process. The genes must be present on different chromosome to assort independently.
Thus, the correct answer is option (c).
Mendel's second law, the Law of Independent Assortment, supports that genes behave as separate particles and alleles of different genes separate independently during meiosis, making the answer both b. and c. are correct.
The question pertains to Mendel's second law, known as the Law of Independent Assortment. This law highlights how alleles of different genes separate independently of one another during the process of meiosis, leading to the gametes containing a mix of alleles. It refutes the concept of blending inheritance, where genes were thought to behave like fluids, and instead, supports the idea of particulate inheritance, where genes behave as discrete units or particles.
Therefore, the statements that are true according to Mendel's second law and his other discoveries are that genes behave like separate particles rather than like fluids, and the alleles of different genes separate independently of one another during meiosis. Hence, the correct answer is: both b. and c. are correct.
What do we mean when we refer to a cell as differentiated?
Answer:
We mean that a cell changes to another type of cell.
Explanation:
Stem cells are a type of cell that has the potential to become a specialized cell, this change or differentiation, is possible thanks to the activation or deactivation of certain genes that promote (or inhibit) the expression of certain proteins that origins different types of cells (fmuscle cells, osteocytes, neurons). This differentiation happens when the cells receive cues internally ( through signals or contact between a group of cells and another or through transcription factors) or externally.
Then, a differentiated cell is a cell that had gone under the previously described process.
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