Answer: The lac operon is an operon used to transport and metabolize lactose. In the presence of lactose, it functions as an inducer, it binds to the Lac I repressor protein and generate a conformational change that decreases its affinity for the operon region. Thus, the operon region is left free, the RNA polymerase can transcribe the structural genes.
Explanation:
An Operon is a group of structural genes whose expression is regulated by the same control elements and genes. The lac operon is an operon used to transport and metabolize lactose in Escherichia coli bacteria. Lactose is a disaccharide formed by the union of a glucose molecule and a galactose molecule (monomers). Upon breaking the glycosidic bond of lactose, both monomers are released and become available for use for energy. Remember that glucose is the main source of energy, and bacteria will always prefer to metabolize glucose rather than any other sugar, which they will only metabolize as an alternative energy source if glucose is not available.
The operon consists of several structural genes:
Lac z gene: encodes the enzyme β-galactosidase, which catalyzes the hydrolysis of lactose into glucose and galactose.Gene lac y: encodes the protein galactoside permease, for the transport of lactose into the bacterium.Promoter: region of DNA upstream of the above-mentioned genes that controls their expression, and where RNA polymerase binds to carry out gene transcription (synthesis of RNA from DNA that involves the expression of a gene).Operator: region of DNA located between the promoter and the beginning of the structural genes, which is recognized by the repressor protein Lac I.Repressor gene: encodes the Lac I repressor protein, which binds to the operator region and thus prevents transcription of genes under the control of this promoter. When the repressor is removed from the operator (in the presence of inducer which is lactose), RNA polymerase is ready to bind and start transcription.So, the lac operon is under a type of negative regulation, where genes can always be transcribed, except when the Lac I repressor protein is bound to the operator region. The promoter of the lac I gene is constitutive, so the Lac I protein is permanently expressed and remains bound to the operator, preventing the transcription of structural genes. That is, preventing the action of the lac operon in the absence of lactose. However, in the presence of lactose, it functions as an inducer of the operon. It is able to bind to the Lac I repressor protein and generate a conformational change that decreases its affinity for the operon region. Thus, the operon region is left free, the RNA polymerase can freely transcribe the structural genes, the enzyme β-galactosidase is synthesized which can degrade lactose to glucose plus galactose (and thus metabolize the lactose in the medium).
It should be clarified that in reality, the true inducing molecule of the lac operon is allolactose, an isomer of lactose obtained by a transglycosylation occasionally carried out by β-galactosidase. But usually to simplify terms, lactose is referred to as the inducer.
So, the lac operon is always inactive unless there is lactose in the medium. As mentioned, E. coli prefers glucose, so the lac operon will not be activated in the presence of lactose if glucose is present in the medium. If both glucose and lactose are present in the medium, the repressor is inactivated, so the operon is transcribed but at a basal (low) level due to the presence of glucose.
which definition best describes a buffer?
Answer:
where are the options
Explanation:
One statement is an example of a scientific observation. Another statement is an example of a scientific explanation. Identify the correct statement for each category to illustrate how scientific explanations are inferred from scientific observations.
Cloning has the potential to
significantly benefit a great many
people, so it should not be
considered immoral or risky.
A scientist thinks that he might
find serious inconsistencies in the
fossil record if he conducts an
excavation in a new location.
The rocks present in western Africa
and eastern South America formed
at the same place and at the
same time.
Even if modern organisms are
found in ancient portions of the
fossil record, this wouldn't challenge
the theory of evolution in any way.
The cloning of organisms is an
exciting area of study, and more
resources should be be devoted
to it.
The age, type, and composition of
ancient rocks in western Africa are
nearly identical to the age, type,
and composition of rocks in
eastern South America.
Answer:
2, 4, and 5 refers to scientific revolution while on the other hand, the remaining statements shows scientific observation.
Explanation:
Cloning has the potential to significantly benefit a great many people, so it should not be considered immoral or risky is refers as scientific observation.
A scientist thinks that he might find serious inconsistencies in the fossil record if he conducts an excavation in a new location is refers scientific explanation because explanation is needed for it which can drawn from the scientific observation.
The rocks present in western Africa and eastern South America formed at the same place and at the same time is scientific observation because the scientists takes the data.
Even if modern organisms are found in ancient portions of the fossil record, this wouldn't challenge the theory of evolution in any way is refers to scientific explanation.
The cloning of organisms is an exciting area of study, and more resources should be be devoted to it so it is refers as scientific explanation.
The age, type, and composition of ancient rocks in western Africa are nearly identical to the age, type, and composition of rocks in eastern South America is scientific observation which is taken by the scientist through research.
Describe the structure and function of the following organelles: nucleus, endoplasmic reticulum, Golgi body, mitochondria, lysosomes, ribosomes, and centrioles
Answer: A cell organelle is defined as a cellular structure which has a specific function. The structure and function of these organelles as explained below.
Explanation:
--> NUCLEUS: This is the largest and most important cell organelle. It is enclosed by a double- layered nuclear membrane with many pores. The structure of the Nucleus makes it the 'control center' of the cell. This, it contains genetic materials( chromosomes) which controls the Production of a new cell or the whole organism itself and it controls the type and quantity of proteins( enzymes) produced in the cytoplasm.
--> ENDOPLASMIC RETICULUM(ER): this is a system of membrane-lined sacs that form channels throughout the cytoplasm. It's membrane is continuous with the nuclear membrane. There are two types of endoplasmic reticulum: rough and smooth. The rough ER packs and transports proteins made by ribosome while the smooth ER is involved in lipid and steroid synthesis.
--> GOLGI BODY: This is a stack of membrane-lined sacs. It is continuously formed at one end and broken off as bubbles or vesicles at the other end. These vesicles carry 'export materials' like enzymes and hormones which the cell makes.
--> MITOCHONDRIA: This is a sausage-shaped body surrounded by a double-membrane layer. The inner membrane is folded to form partitions which project into the inside of the mitochondria. The energy producing reactions of cellular respiration take place in the mitochondria. It is thus often called the cell's 'power- house'.
LYSOSOMES: These are small round sacs that contains digestive enzymes which break down structures and substances. They are also involved in the transport of materials in and out of the cell.
RIBOSOME: These are found on the surface of rough endoplasmic reticulum and are sites for protein synthesis of the cell.
CENTRIOLE: Two rod-like centrioles are found at right angles to each other in an animal cell. They are found near the nucleus and seem to be concerned with cell division.
Name the newly and recent discovered ocean? comment
Nêu 2 cách hoạt động của glutathion trong tế bào hồng cầu
Answer:
Glutathione
GlutathioneGlutathione là một trong những thành phần tự nhiên bên trong cơ thể con người, đóng vai trò vô cùng quan trọng đối với sức khỏe mỗi chúng ta. Ngoài việc được sản xuất tự nhiên bởi cơ thể, glutathione có thể được tiêm qua đường tĩnh mạch, dạng viên uống hoặc dưới dạng thuốc hít.
GlutathioneGlutathione là một trong những thành phần tự nhiên bên trong cơ thể con người, đóng vai trò vô cùng quan trọng đối với sức khỏe mỗi chúng ta. Ngoài việc được sản xuất tự nhiên bởi cơ thể, glutathione có thể được tiêm qua đường tĩnh mạch, dạng viên uống hoặc dưới dạng thuốc hít.1. Glutathione là gì?
GlutathioneGlutathione là một trong những thành phần tự nhiên bên trong cơ thể con người, đóng vai trò vô cùng quan trọng đối với sức khỏe mỗi chúng ta. Ngoài việc được sản xuất tự nhiên bởi cơ thể, glutathione có thể được tiêm qua đường tĩnh mạch, dạng viên uống hoặc dưới dạng thuốc hít.1. Glutathione là gì?Glutathione (GSH) là một chất tự nhiên được sản xuất tự nhiên bởi gan và được tìm thấy trong hoa quả, rau và thịt và được tổng hợp từ tế bào bằng 3 amin gồm: Cysteine, glutamic và glycine.
GlutathioneGlutathione là một trong những thành phần tự nhiên bên trong cơ thể con người, đóng vai trò vô cùng quan trọng đối với sức khỏe mỗi chúng ta. Ngoài việc được sản xuất tự nhiên bởi cơ thể, glutathione có thể được tiêm qua đường tĩnh mạch, dạng viên uống hoặc dưới dạng thuốc hít.1. Glutathione là gì?Glutathione (GSH) là một chất tự nhiên được sản xuất tự nhiên bởi gan và được tìm thấy trong hoa quả, rau và thịt và được tổng hợp từ tế bào bằng 3 amin gồm: Cysteine, glutamic và glycine.Nồng độ glutathione trong cơ thể có thể bị suy giảm bởi một số yếu tố, bao gồm dinh dưỡng kém, độc tố từ môi trường và sự căng thẳng. Ngoài ra, nồng độ của nó cũng có thể bị suy giảm dần theo tuổi tác.
GlutathioneGlutathione là một trong những thành phần tự nhiên bên trong cơ thể con người, đóng vai trò vô cùng quan trọng đối với sức khỏe mỗi chúng ta. Ngoài việc được sản xuất tự nhiên bởi cơ thể, glutathione có thể được tiêm qua đường tĩnh mạch, dạng viên uống hoặc dưới dạng thuốc hít.1. Glutathione là gì?Glutathione (GSH) là một chất tự nhiên được sản xuất tự nhiên bởi gan và được tìm thấy trong hoa quả, rau và thịt và được tổng hợp từ tế bào bằng 3 amin gồm: Cysteine, glutamic và glycine.Nồng độ glutathione trong cơ thể có thể bị suy giảm bởi một số yếu tố, bao gồm dinh dưỡng kém, độc tố từ môi trường và sự căng thẳng. Ngoài ra, nồng độ của nó cũng có thể bị suy giảm dần theo tuổi tác.2. Công dụng của Glutathione
GlutathioneGlutathione là một trong những thành phần tự nhiên bên trong cơ thể con người, đóng vai trò vô cùng quan trọng đối với sức khỏe mỗi chúng ta. Ngoài việc được sản xuất tự nhiên bởi cơ thể, glutathione có thể được tiêm qua đường tĩnh mạch, dạng viên uống hoặc dưới dạng thuốc hít.1. Glutathione là gì?Glutathione (GSH) là một chất tự nhiên được sản xuất tự nhiên bởi gan và được tìm thấy trong hoa quả, rau và thịt và được tổng hợp từ tế bào bằng 3 amin gồm: Cysteine, glutamic và glycine.Nồng độ glutathione trong cơ thể có thể bị suy giảm bởi một số yếu tố, bao gồm dinh dưỡng kém, độc tố từ môi trường và sự căng thẳng. Ngoài ra, nồng độ của nó cũng có thể bị suy giảm dần theo tuổi tác.2. Công dụng của GlutathioneTùy thuộc vào từng cách sử dụng cũng như mục đích sử dụng của người bệnh mà Glutathione mang đến những công dụng khác nhau, cụ thể là:
GlutathioneGlutathione là một trong những thành phần tự nhiên bên trong cơ thể con người, đóng vai trò vô cùng quan trọng đối với sức khỏe mỗi chúng ta. Ngoài việc được sản xuất tự nhiên bởi cơ thể, glutathione có thể được tiêm qua đường tĩnh mạch, dạng viên uống hoặc dưới dạng thuốc hít.1. Glutathione là gì?Glutathione (GSH) là một chất tự nhiên được sản xuất tự nhiên bởi gan và được tìm thấy trong hoa quả, rau và thịt và được tổng hợp từ tế bào bằng 3 amin gồm: Cysteine, glutamic và glycine.Nồng độ glutathione trong cơ thể có thể bị suy giảm bởi một số yếu tố, bao gồm dinh dưỡng kém, độc tố từ môi trường và sự căng thẳng. Ngoài ra, nồng độ của nó cũng có thể bị suy giảm dần theo tuổi tác.2. Công dụng của GlutathioneTùy thuộc vào từng cách sử dụng cũng như mục đích sử dụng của người bệnh mà Glutathione mang đến những công dụng khác nhau, cụ thể là:2.1 Sử dụng Glutathione dạng uống để điều trị
A species of wasp dies out in a prairie ecosystem. This species used to perform the important task of pollinating a widespread plant species. This ecosystem will be less damaged by this local extinction if
Answer:
C.
there are other insect species that also pollinate the plant.
Explanation:
2. Would a footprint be considered a fossil?
Answer:
yes i think so
Explanation:
Some microorganisms cause human disease. Other microorganisms are used in making cheese, yogurt, and bread. Based on this information, the relationship between humans and microorganisms can be
A) beneficial, only
B) harmful, only
C) beneficial or harmful
Given the above result, Daniel’s doctor prescribes him antibiotics to be taken for 10 days. Daniel doesn’t like to swallow pills and decides to see if he will improve on his own without the antibiotics. Approximately 20 days after his initial symptoms Daniel notices new symptoms that included painful, swollen joints, shortness of breath, chest pain, and a skin rash that developed ring-shaped eruptions on the upper parts of his legs/arms and on his trunk. His doctor confirms that he has carditis (inflammation of the heart). Daniel’s disease has progressed to a more serious condition, what is this new condition?
Answer:
below
Explanation:
Myocarditis
1. Which of the following reproduce using spores?
wild flowers
pine tress
vegetable plants
mosses and ferns
PLEASE HELP MEEE
ASAP
URGENT
Answer:
pine trees
Explanation:
pine trees grow in cold areas where seed cannot be placed in flowers or fruits. hence they are placed in pine cones which protect the seed from cold and harsh weathers
Answer:
Mosses and Ferns
I did the test and this was the answer, hope this helps
Which organism is an example of a producer?
moth
mushroom
rose bush
cheetah
Answer
Rose Bush
Explanation:
Rose bush is an example of a producer. Therefore, the correct statement is option C.
What are producers?Producers are organisms that produce their own food through photosynthesis and form the base of the food chain by providing food for all other organisms in the ecosystem. For example, plants, algae, and some bacteria are few examples of producers.
The rose bush is a producer belonging to the kingdom Plantae and can produce its own food through photosynthesis where it converts light energy into chemical energy. The rose bush also contains specialized structures called chloroplasts to carry out photosynthesis.
Moths and cheetahs cannot produce their own food. Moths, on the other hand, are insects belonging to the class Lepidoptera and feed on plants or other insects and mushrooms obtain their nutrients from dead organic matter and are decomposers which play an important role in breaking down organic matter in the ecosystem.
Therefore, rose bush is an example of a producer.
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state two functions of blood plasma
Answer:
"The main role of plasma is to take nutrients, hormones, and proteins to the parts of the body that need it. Cells also put their waste products into the plasma."
Why are Thermophiles important in science
Answer:
Thermophiles, predominantly bacilli, possess a significant potential for the degradation of environmental pollutants, including all major classes
Explanation:
i know.
Answer:
Thermophiles, predominantly bacilli, possess a significant potential for the degradation of environmental pollutants, including all major classes.
So as thermophiles have become increasingly important in biotechnological research, the number of bioprospecting groups searching for useful organic compounds in nature have dramatically increased as well.
Hope it helps >3!
Please help asap
Write the name of each structure on the lines below indicated by a letter in the image above. a. _______________________ b. _______________________ c. _______________________ d. _______________________
Answer:
The correct answer is -
A. axon
B. dendrite
C. neurotransmitter
D. Synapse
Explanation:
The given diagram is the representation of two neurons connected by the chemical signal. Each neuron has a nerve fiber that carries the nerve signal from one neuron to another covered with sheath, this body is called Axon.
Axon is connected with dendrite, which receives a signal from other neurons and is arise from the cell body of neurons in various numbers. The site where two neurons meet called synapse which is releases neurotransmitters a chemical signal molecule.
Marco is given an immortal cell line of epithelial cells to dilute. The initial concentration is 12.5 million cells. If he does four 1:10 serial dilutions, what will be the concentration of the last serial dilution
Answer: 12.5 x 10^6/10000 = 1250 cells.
Explanation:
A serial dilution is the step-by-step reduction of the concentration of a solution. Usually, the dilution factor at each step is constant, resulting in a geometric progression of the concentration, which is logarithmic. Serial dilutions are used to create very dilute solutions by accurately reducing the concentration of a substance.
It is usually carried out in experiments where highly dilute solutions are needed, for example, those involving logarithmic scale concentration curves or those used to determine the density of bacteria. To do this, prepare several test tubes with, for example, 9 ml of dilution liquid and first add 1ml of the undiluted sample to the first tube and then make serial dilutions in the following tubes. The first tube will contain a 1:10 dilution, the second 1:100, the third 1:1000, the fourth 1:10000 and so on.
Use 1 ml of undiluted (stock) solution with a pipette into the first test tube, containing 9 ml of a liquid, which can be for example water, Phosphate-buffered saline (PBS) and mix. This is the 1:10 solution. For the second dilution, take 1 ml of the dilution from the 1:10 tube and add it to the 9 ml of liquid to make the 1:100 tube and mix. The third tube is prepared with 1 ml of the 1:100 solution and 9 ml of liquid and this will be the 1:1000 dilution. The last one is prepared with 1 ml of 1:1000 and 9 ml of liquid and it will be 1:10000 (the fourth dilution).
So, if you start with 12.5 million cells and dilute four times with serial dilutions of 1:10 each, the final concentration will be four times lower:
12.5 x 10^6/10000 = 1250 cells.
Compare your observations of micrograph obtained from your the optical microscope, the scanning electron microscope and the transmission electron microscope?
Answer:
Scanning Electron Microscopes (SEM) Transmission Electron Microscopes (TEM)
Electron stream Fine, focused beam Broad beam
Image taken Topographical/surface Internal structure
Resolution Lower resolution Higher resolution
Magnification Up to 2,000,000 times Up to 50,000,000 times
Explanation:
Answer:
Scanning electron microscope: is useful for detailed study of the topography of a specimen.
Transmission electron microscope: is used to study the internal structure of cells.
Use the diagram to answer the question below. The cell membrane plays an essential role in
the life of the cell. How does the cell membrane help maintain the health of the cell in the figure
below?
Vacuole
Cell
membrane
Nucleus
Cell
wall
Chloroplast
a. The cell membrane contains genetic information of the cell.
b. The cell membrane provides support and protection for the cell.
c. The cell membrane is where protein molecules are manufactured in a cell.
d. The cell membrane regulates the movement of materials in and out of the cell.
Answer:
D for me
Explanation:
correct me if I'm wrong
loved to help people :)
Answer:
A.selectively permeable
Source:trust me bro
ATP → ADP + Pi is an example of a(n) ________ reaction.
Answer:
ATP → ADP + Pi is an example of a(n) catabolic reaction.
ATP → ADP + Pi is an example of a decomposition reaction.
A decomposition reaction is a type of reaction where a molecule breaks down into two or more molecules/products.Decomposition reactions can be divided into three classes: Thermal decomposition reactionPhoto decomposition reactionElectrolytic decomposition reactionAdenosine thiophosphate (ATP) is the primary energy source for cellular processes in the cells.ATP can be hydrolyzed to Adenosine diphosphate (ADP) and monophosphate (Pi) by the addition of water, thereby releasing energy.In conclusion, ATP → ADP + Pi is a type of decomposition reaction.
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help please!
Is there a physical or behavioral characteristic that allows red beetles to be so
successful?
what bond is broken when energy is released?
Answer:
Bonds are both broken and made in chemical reactions but many biology teachers and textbooks state that "Breaking ATP bonds releases energy." In reactions bonds are broken and made. If the strength of the bonds formed exceeds the strength of the bonds broken the reaction is exothermic.
Explanation:
Hope this helps. :)
Write Ratio 10 :35 in the form 1:n
1:3.5
Hope this helps! :)
A dialyzing machine has a membrane that is permeable to water, urea, uric acid, ammonia, salts, and
glucose. The membrane is impermeable to protein molecules. In relation to the blood flowing
through the dialysis machine, the dialyzing solution must have:
a. the same concentrations of urea and salts
b. lower concentrations of glucose and protein
c. lower concentrations of urea, uric acid, and ammonia and higher or equal concentrations of glucose
d. higher concentrations of urea, uric acid, and ammonia and lower or equal concentrations of glucose
Answer:
C. lower concentrations of urea, uric acid, and ammonia and higher or equal concentrations of glucose
Explanation:
Hope it helps!!!
The photograph shows soil layers. What is the bottom layer of soil?
Answer:
bed rock
Explanation:
ok ok ok ok ok ok ok ok ok ok ok
which of the following is a type of wave that does not need a medium though which to travel?
A.) equilibrium
B.) longitudinal
C.) amplitude
D.) transverse
Answer:
The answer is D) Transverse
Explanation:
Electromagnetic waves which are in transverse (by nature) can travel withought a medium.
Why earth is warmer at the equator?
Answer:
Why is it hotter at the equator than it is at the poles? ... Because the sun's rays hit the earth's surface at a higher angle at the equator.
The inheritance of genetic traits from parents to children follows predictable rules. Knowing that each parent contributes genes equally to each child, what determines an inherited trait such as eye color? Select one: a. Only the interaction between dominant genes. b. Only the interaction between recessive genes. c. The interaction between dominant and recessive genes does not determine inherited traits. d. The interaction between dominant and recessive genes.
Answer:
The correct answer is - D. The interaction between dominant and recessive genes.
Explanation:
The inheritance of genetic traits come from both parents and based of their gene it can be predicted what traits might found in the offspring. There two types of traits of a single gene, known as alleles. These alleles can be dominant which means they can mask the effect of another allele if present together. The allele that get masked by the dominant allele called the recessive allele. The interaction of both recessive and dominant alleles determines an inherited trait such as eye color.
Termite guts hosts a wide variety of microorganisms: bacteria, archaea and various protists exhibiting diverse ways of acquiring their nutritional needs. Which of the following modes of feeding is NOT found in the termite guts? a. Chemotrophs b. Heterotrophs c. Photoautotrophs d. Parasites e. Decomposers
Answer:
The correct answer is - C. Photoautotrophs.
Explanation:
Photoautotrophs are autotrophs or organisms that are able to obtain their food by using photosynthesis. Photosynthesis is the process in which sunlight trapped by the organism and converts to inorganic material such as CO2 and H2O to organic material which is glucose or sugar molecules.
In termite's guts, various types of diverse ways of getting their nutritional needs are found according to the microbes are Chemotrophs, Heterotrophs, parasites, and decomposers.
number of cell that undergo meiotic division to produce a 216 gametes in gymnosperms is
meiotic devision this is the answer it might help you
In which season(s) are the most populations limited in Mono Lake?
Answer:
Mainly winter i think
Explanation:
If a DNA sample were composed of 15% adenine, what would be the percentage of thymine?
a. 15.
b. 30.
c. 35.
d. 50.
Answer:
C: 35
Explanation:
if DNA molecule contains 15% adenine then C and G will constitute 70%,of which guanine will be 35%