Cells can be prokaryotic or eukaryotic. Which of the following structures is present in eukaryotic cells but not in prokaryotic cells?
Answer:
nucleus
Explanation:
eukaryotic has a nucleus, prokaryotic does not
Early genetic manipulation of petunias included an attempt to engineer dark purple petals. To this end, extra copies of the gene that causes purple pigment was engineered to be produced in the petunia. However, to the surprise of many, the plants carrying the extra copies of the purple gene were completely white or only had patches of color. Molecular analysis revealed that the purple gene was reduced 50-fold in the engineered plants compared to wild type. Provide a possible explanation how this occurred. Also, provide a possible experiment that may overcome this setback
Answer:
The altered pigmentation in transgenic petunia plants is caused by the RNA interference (RNAi) mechanism
Explanation:
The RNA interference mechanism is a naturally occurring mechanism by which single-stranded RNA molecules can bind to complementary mRNAs in order to inhibit gene expression, blocking translation and leading to mRNA degradation. The example above described is a classical genetic experiment (Napoli et al. 1990 ) that showed the existence of the RNAi pathway by the overexpression of a chimeric chalcone synthase (CHS) gene in pigmented petunia flowers, which blocked anthocyanin biosynthesis. In this experiment, irregularly bicolored/white flowers in transgenic petunias containing exogenous pigmentation genes were developed. The co‑suppression of gene expression was produced by the high-copy-number transcription of the CHS transgene, showing the existence of an undescribed RNAi silencing mechanism. Somatic reversion of the altered phenotype can be achieved by restoring the normal mRNA levels for these pigmentation genes, e.g., by a progeny testing in order to eliminate transgenic CHS expression.
mRNA has 1500 bases. If all of them are used for coding amino acids, the number of amino acids in polypeptides will be ?
Answer:
499
Explanation:
What does polar ice do to much of the incoming sunlight?
Answer:
Arctic sea ice keeps the polar regions cool and helps moderate global climate. Sea ice has a bright surface; 80 percent of the sunlight that strikes it is reflected back into space. As sea ice melts in the summer, it exposes the dark ocean surface.
Explanation:
what are the two phases of the respiratory movement of man? Are they the same in a grasshopper or a fish?
The two phases of the respiratory movement of man is inspiration ( or inhalation) and expiration (or exhalation). The phases of the respiratory movement of men is the same in fish because they also inhale and exhale.
What is inspiration (inhalation ) ?
Inspiration (inhalation) is the process of taking air into the lungs. It is the active phase of ventilation because it is the result of muscle contraction.
What is expiration (exhalation)?
Expiration (exhalation) is the process of letting air out of the lungs during the breathing cycle.
To learn more about inspiration and expiration here
https://brainly.com/question/21822744
#SPJ2
All stories must have words.
A. True
B. False
Answer: False
Explanation: Because a story can be told with actions or signals.
Answer:
False
Explanation:
Stories can be told with an object or a series of photos not exclusively words. I hope that this helps :)
PLEASE HELP PLEASE!!!!!
why is it difficult for scientists to study the mechanism of evolution
Answer:
Because evolution is not a simple process and it is hard to accurately determine how a species evolved or what the species evolved from.
Which best compares self-renewal and differentiation?
Answer:
Only differentiation creates more of the same types of cells. ... Only self-renewal creates more of the same types of cells. Only self-renewal depends on gene expression
Answer:
Only differentiation creates more of the same types of cells. ... Only self-renewal creates more of the same types of cells. Only self-renewal depends on gene expression.
Explanation:
please give me brain list and follow
Tubelike cells that carry food from the leaves to other parts of the plant are called?
Question 1 options:
Xylem
Phloem
Chloroplasts
Answer: Phloem carry food from the leaves to other parts of the plant
Explanation: Xylem carry water and Chloroplasts are organelles in cells wich allow the plant to photosynthesise
What temperature system is used by most of the world
Answer:
The temp system used by most of the world is Celcius
Answer:
The metric system, including Celsius, is the official system of measurement for almost all countries in the world. Most scientific fields measure temperature using the Celsius scale. Zero degrees Celsius is the freezing point of water, and 100 degrees Celsius is the boiling point of water.
Explanation:
The English moth, Biston betularia, is often cited as an example of observed evolution. There are two colors of this moth, light and
dark (typica and carbonaria). Kettlewell found that dark moths constituted less than 2% of the population prior to 1848. Then, the
frequency of the dark coloration began to increase. By 1898, the 95% of the moths in Manchester and other highly industrialized
areas were of the dark color. Using the moth example, analyze the events in order to identify support for the statement: natural
selection changes populations, not individuals. Choose ALL that apply.
A)
Variation in the population existed.
B)
Color variation is a result of different gene combinations.
C)
In response to environmental change, moth coloration changed from light
to dark.
D)
Due to natural selection, the ratio of different genetic combinations is
changing
E)
Predator pressure resulted in the light colored genotype being removed
from the gene pool.
Answer:
A,B,C,F
Explanation:
A, B, C and D all of these statements support the idea that natural selection changes populations, not individuals.
What is natural selection?Natural selection is a process by which organisms that are better adapted to their environment are more likely to survive and reproduce, passing on their advantageous traits to their offspring. This leads to changes in the genetic makeup of a population over time, as advantageous traits become more common and less advantageous traits become less common.
Natural selection is driven by environmental pressures, such as predators, competition for resources, or changes in climate. It is a key mechanism of evolution, and helps to explain the diversity of life on Earth and the ways in which different species have adapted to their environments.
Learn more about natural selection, here;
https://brainly.com/question/2725702
#SPJ6
Which observation best explains how the landform in the image was created ! PLEASE HELP !!!!!!!
Answer:
dreams have been formed through the process of erosion
Explanation:
because it looks like little water streams cutting through the rock so it must have been eroded
Poiseille's law is often used to calculated the arteriolar blood flow. According the this law, the following all affect blood flow:-radius of vessel-length of vessel-viscosity of blood-pressure gradientWhich of these has the GREATEST affect on blood flow?
Answer:
a. radius of vessel
You are studying ion channels and have set up model lipid vesicles containing the three following transporters:
1. a Na+ /H+ antiporter driven by the Na+ concentration gradient.
2. The common 3Na+ /2K+ pump.
3. K+ leak channels. The experiments are designed such that all three transporters are oriented in the model lipid bilayers in the same direction they would be in the plasma membrane of a cell and that concentration gradients in vitro mimic the concentration gradients experienced by cells (e.g., the extracellular Na+ concentration is similar to the concentration outside of the vesicle whereas the concentration in the lumen of the model vesicles is similar to intracellular Na+ levels).
Required:
a. Draw the arrangement and ion flow of the three types of transporters in the model membranes.
b. What do you predict will happen to the pH of the vesicle lumen if you treat the model membranes with the drug oubain that impairs function of the 3Na+/2K+ pump? Briefly explain your answer in terms of what happens with each transporter.
Answer and Explanation:
a) you will find the arrangement and ion flow of the three types of transporters in the model membranes in the attached files.
K+ leak channels are channel proteins that allow K⁺ to leave the cell in favor of its concentration gradient. It keeps a stable equilibrium by taking out K⁺ that the 3Na+ /2K+ pump brings into the cell. Any alteration in the pump leads to an alteration in the leak channel functioning. Na+ /H+ antiporter is an integral membrane protein, and a secondary transporter is responsible for the interchange of H+ and Na+ through the membrane with no use of energy. It regulates pH within the cell. It responds to the Na+ and H+ concentration gradient, determined by the 3Na+ /2K+ pump. An alteration in the pump functioning produces a change in the Na gradient and consequently affects the antiporter interchange action. 3Na+ /2K+ pump is an integral protein that transports K+ and Na+ against the electrochemical gradient. A significant amount of energy is used to make the pump function. It brings K+ into the cell and takes Na+ out of it. It keeps the membrane potential and the electrochemical gradient constant. The pump function is associated with the leak channels and the antiporters function.Under normal conditions, the cell interior has a lower pH than the exterior. The K+ concentration is higher in the interior, while the Na+ concentration is higher in the cell exterior. The interior of the cell is always more electronegative than the cell exterior.
b)
The drug ouabain inhibits the pump. It impedes the Na+ exit and the K+ entrance. It occurs a sharp increase in the Na+ intracellular concentration, which influences the Na+ /H+ antiporter that changes the ions´ direction, taking out Na+ and bringing in H+ to compensate the intracellular Na+ excess. There is also a decrease in the leak channel function, which does not allow K+ to leave the cell.
Whenever the pump is inhibited, there is an increase in the intracellular pH, because Na+ concentration increases in the interior.
What the consequences would be if the entire water surface was covered with water lilies
Answer: There can be a ton of damage done if water lilies overgrow.
Explanation:
Water lilies protect the organisms under the body of water and provide shade to the plants and organisms underneath. These are very important for organisms, as they also provide a place to rest. But if the entire water surface were to be covered with water lilies, this would be a major problem, because sunlight would have no way of reaching below the surface, and this would decrease oxygen levels for plants and organisms. Without air and sunlight, plants will start to die and organisms of the body of water will also start to die because of no air to breathe. Also, overgrowth of water lilies causes water stagnation and leads to excessive algae blooms. The stagnant water attracts insects like mosquitoes, cockroaches, termites, and more pests which can harm plants and organisms.
Signals from nearby cells on how to differentiate are examples of an:
internal cue
external cue
Answer:
External Cue..........
Answer:
I just want points
Explanation:
What is the importance of living systems?
A phycologist is interested in testing the claim that the proportion of algae from a local rivulet that belonged to the particular phylum cyanobacteria is at least half. A random sample of 50 alga was obtained and each alga was categorized as either being cyanobacteria or not. It was found that 38 were, in fact, cyanobacteria. The test statistic for this hypothesis test is...
Answer:
The test statistic for this hypothesis test is - 3.68.
Explanation:
A test statistic is a random variable that is calculated from sample data and used in a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis.
Sample proportion = 38/50
= 0.76
Hence,
Test statistic
[tex]= \frac{0.76-0.50}{\sqrt{0.50*0.50/50}}[/tex]
= 3.68
The organelle that is the site of cellular respiration is the
o mitochondrion
O nucleus
o chloroplast
o ribosome
Answer:
hope this helps
Explanation:
mitochondrion
Answer:
mitochondrion
Explanation:
Plz mark brainliest thanks
How do organisms obtain energy from an ecosystem?
Answer:
Plants obtain food by photosynthesising
Herbivores obtain food by eating plants
Carnivores obtain food by eating an animal
Where do substrates bind on an enzyme?
active site
surface receptor
voltage-gated
channels
calcium channels
An unknown bacterium has been inoculated onto a Mannitol Salt Agar plate and incubated at 37 degrees C. After 48 hours, you observe the plate. What interpretations and conclusions can be made from this result
Explanation:
Halotolerant is the ability of the organism to grow at the higher concentration of salt than the required concentration for its growth.
As we know Mannitol salt is used as selective medium for isolation of pathogenic bacteria. The medium has mannitol salt, phenol red indicator, 7.5% sodium chloride. This high salt concentration inhibits the growth of most bacteria.
The interpretations and the conclusion regarding to the given situation should be explained below.
What is Halotolerant?It is the capability of the organism for growing at a higher concentration of salt as compared to the concentration with respect to the growth. Since Mannitol salt should be applied as the selective medium for isolation of pathogenic bacteria. The medium contained the mannitol salt, phenol red indicator, 7.5% sodium chloride.
learn more about bacteria here: https://brainly.com/question/16537143
While they aren't spiders, Grandaddy Long legs, Horseshoe Crabs, and
Scorpions all belong to this group of organisms. *
Insecta
Crustacea
Arachnida
Nemertea
wait i may be dum but it sounds like your stating something rather then asking.. could you maybe reword the question?
The unit of measurement for forces is called
Answer:
I am pretty sure its called a Newton=unit of force
what type of symbiotic relationship is between the anémone and the clow fish?
A.Commensalism
B.Paratism
C.Predation
D.Mutualism
The answer is D. Mutualism
HELLLPPPP REMEMBER IS DUE SOON !!!!! I WILL GIVE YOU A BRANLIEST !!!!!!!!!!!!!|
A scientist finds a tiny fragment of a bone too small to be classified by its appearance. The scientist studies the tiny fragment and concludes that it belonged to an ancient primate species. How was the scientist able to classify the bone?
Answer:
Through a microscope.
Explanation:
A stereozoom microscope is a handy instrument for magnifying small features on the surface of a bone.
Answer:
Through a microscope
Explanation:
I just know
Mode of Action of the Herbicide DCMU When chloroplasts are treated with 3-(3,4- dichlorophenyl)-1,1-dimethylurea (DCMU, or diuron), a potent herbicide, O2 evolution and photophosphorylation cease. Oxygen evolution, but not photophosphorylation, can be restored by addition of an external electron acceptor, or Hill reagent. How does DCMU act as a weed killer
Answer:
It acts as a weed killer by blocking photosynthesis
Explanation:
Photosynthesis is important to plants because it is their principal form of energy.
When DCMU is introduced to weeds, what it does is to block or slow down the process of photosynthesis. Carbon dioxide fixation is slowed down causing weeds to die off. DCMU strongly slows down photosystem II. When this is done, lipid and protein membranes would get destroyed and the weed cells would begin to dry and shed off
When fruits or vegetables are left exposed to the air after they have been boiled, they don't turn brown. How can you explain this?
Answer:
I guess cuz u didn't use direct heat with fire, just hot water
Explanation:
2. What does proper disposal of hazardous waste prevent?
function of nervous tissue