Answer:
Charged tRNA
Explanation:
The first time the expereiment was performed was on the 15th of May in 1961 by two men Marshall W. Nirenberg and his post doc, J. Heinrich Matthaei. This experiment is now called the Nirenberg and Matthaei experiment where they used ruptured E.coli cells, RNA and labelled tRNA to decipher the triplet codon that matched to specific amino acid. By the time the experiment was complete the men had found 64 amino acid codons which was a large contribution to genetics and molecular biology.
Which regions of the vascular bed is the actual site of gas exchange with surrounding tissue?
Explanation:
Explanation:
Many biofilm-specific phenotypes are controlled by "quorum sensing." This system allows bacteria to regulate gene expression according to the concentration of in its immediate environment.a) trueb) false
Answer:
True
Explanation:
this has been seen as an evolutionary step in bacteria activity. it also allows them to control the activity of the the whole community
Answer: A) True
Quorum sensing is the system that allows bacteria to regulate gene expression according to the concentration of in its immediate environment.
Explanation: Quorum sensing is the process by which bacteria cells communicate among/within themselves and share information about their density and as well adjust their gene expression accordingly.
In quorum sensing ,there is production, detection and response of bacteria cells to Autoinducers (extracellular signalling molecules).
Increase in bacterial population density brings about the accumulation of autoinducers in the environment,the bacteria cell now monitors the information of the autoinducers inorder to track changes in their cell number and collectively alter their gene expression.
Quorum sensing controls the disease causing ability of a bacterial cell.
Transcription in eukaryotes requires which molecules in addition to rna polymerase?
Answer:i d k
Explanation:
Answer:
several transcription factors
Two-component regulatory systems rely on a balance of phosphorylation and dephosphorylation of sensor kinases and response regulators. If the response regulator became permanently phosphorylated due to lack of phosphatase activity, which of the following would NOT happen? Hints O The cell would become more sensitive to the environmental stimulus The cell would become insensitive to the environmental stimulus. The cell would not be able to "reset" its response cycle. O The operon controlled by the response regulator would be always transcribed or never transcribed, depending upon the regulatory role of the response regulator.
Answer:
The correct answer is the first statement.
Explanation:
A fundamental stimulus-response coupling mechanism that helps various species to react and sense different modifications taking place in various distinct environmental circumstances is known as a two-component regulatory system. Though this system is found in almost all the domains of life, however, it is generally witnessed in species like bacteria, mainly in the Gram-negative and cyanobacteria.
In case, if the response regulator turns completely phosphorylated because of the absence of phosphatase activity, the cell would become insensitive towards the environmental stimulus. This generally happens as the cell will lose its tendency to sustain the response cycle because of the imbalance in the dephosphorylation and phosphorylation system that helps in sustaining the response of the cell towards a specific environmental stimulus.
Hair turns color when we age because the follicles at the base of the hair shaft cease to produce melanin. Melanin is a chemical that gives the hair shaft its color (black, brown, blond, red, and all shades in between). The darkness or lightness of your hair depends on how much melanin each strand contains. With age, the cells in the follicle that produce melanin die off. As they do so, that hair strand will become silver, grey, or white, as it grows. a. Argument; conclusion: The follicles ... cease to produce melanin.
b. Argument; conclusion: Hair turns color when we age.
c. Argument; conclusion: With age, the cells in the follicle ... die off.
d. Nonargument.
e. Argument; conclusion: The darkness or lightness ... each strand contains.
Answer:
Explanation:
D
The inner membranes of both mitochondria and chloroplasts are folded into various arrangements. What is the advantage of having a folded membrane rather than a simple interior membrane that follows the same oval shape as the exterior membrane?
The question is incomplete as itt does not have the options which are:
A) The folds in the membranes are a physical barrier for compounds that attempt to enter the organelle.
B) The folds allow for more surface area for the chemical reactions that occur across the inner membranes.
C) The folds allow these organelles to interact more efficiently with Golgi bodies.
D) The folds cause a necessary change in the organelles' internal pH.
Answer:
B) The folds allow for more surface area for the chemical reactions that occur across the inner membranes.
Explanation:
The mitochondria and chloroplast are double-membrane organelle that contains the outer and inner layer.
The outer layer is usually smooth of both the chloroplast and mitochondria but the inner membrane is not regular but folded.
The folding is an adaptive feature of these organelle to increase the surface area. The increased surface area allows the more ATPase in the inner membrane, therefore, increases the amount of ATP generated.
Thus, Option-B is correct.
Answer: Increased surface area.
Explanation:
The inner membrane of the chloroplast and mitochondria is folded because they provide maximum surface area for the processes takes place in the organelles.
The mitochondria helps in energy production by converting the glucose in adenosine triphosphate.
The chloroplast helps in providing maximum surface area for the process of photosynthesis.
The main advantage is the surface area which helps the organelle perform its function more efficiently.
What is the best way to promote fusion between two related populations of mosquitofish, one of which lives in a predator-rich pond and the other of which lives in a predator-poor pond?
Answer:
Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators.
Explanation:
On the Bahaman island of Andros mosquitofish populations live in various, now isolated, freshwater ponds that were once united. Currently some predator-rich ponds have mosquito fish that can swim in short, fast bursts, while other predator-poor ponds have mosquito fish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquito fish exhibit exclusive breeding preferences.
One device used for electrical safety involves a metal strip that bends when it gets hot. This bending flips a switch which interrupts the current. What is this device called?
Answer: An Electrical fuse
Explanation: An electrical fuse is a small, thin metallic conductor designed to melt and/or separate into two pieces for the purpose of breaking a circuit. electrical fuse interrupts circuit current in the event of electrical hazard. A circuit breaker is designed to automatically disconnect to an overcurrent condition.
Suppose two plant populations exchange pollen and seeds. In one population, individuals of genotype AA are most common (9,000 AA, 900 Aa, 100 aa), while the opposite is true in the other population (100 AA, 900 Aa, 9,000 aa). If neither allele has a selective advantage, what will happen over time to the allele and genotype frequencies of these populations?
Answer:
selection is not important at this locus; furthermore, the populations are no small, and hence the effects of genetic drift should not be pronounced, gene flow is occurring via the movement of pollen and seeds, thus, allele and genotype frequencies in these populations should become more similar over time, with regards to this locus, as a result of gene flow.
Explanation:
A microbiologist inoculates a growth medium with 100 bacterial cells/ml. If the generation time of the species is 1 hour, and there is no lag phase, how long will it be before the culture contains more than 10,000 cells/ml? a) 2 hours
b) 3 hours
c) 24 hours
d) 7 hours
Answer:
Option D
Explanation:
Given -
The lag phase is zero.
Generation time is the time required to double the population of bacteria.
This means that after every one hour the population of bacteria will get double.
Bacterial count at the starting when t is
Bacterial count at t is
Bacterial count at t is
Bacterial count at t is
Bacterial count at t is
Bacterial count at t is
Bacterial count at t is
Bacterial count at t is
Hence, after seven hours the culture will contains more than 10,000 cells/ml
Option D is correct
The earth's atmosphere:_______. a) is made mostly of oxygen helps recycle water b) protects the earth from harmful radiation c) reduces the temperature extremes between day and night recycles d) carbon dioxide and oxygen
Explanation:
Answer:
c
Explanation:
Salts and sugars work to preserve foods by creating A) lower osmotic pressure. B) hypotonic environment.
C) lower pH.
D) hypertonic environment.
E) depletion of nutrients.
Answer:
D) hypertonic environment
Explanation:
A hypertonic environment consists of a solution in which amount of solute outside the cell is more than the amount inside the cell. When the concentration of solutes is greater on the outside of a cell, water would move from inside the cell to outside of the cell, where the concentration is lower, hence causing shrinking of the cell.
Salt and sugar create a hypertonic environment in foods, thereby making the cells of food spoilage organisms to shrink and unable to thrive in the environment.
Is the flower the cantaloupe in the plant?
Answer:
The cantaloupe is not a flower but it is the fruit the plant bears
Air masses are defined by which key terms? A Polar
B Tropical
C Maritime
D Continental
E all of the above
Answer: b
Explanation:
Air masses are defined by which key terms? A Polar
B Tropical
C Maritime
D Continental
E all of the above
Answer:
E - all of the above
Explanation:
In meteorology, an air mass is a volume of air defined by its temperature and water vapor content.
Colder air masses are termed polar or arctic. While warmer air masses are deemed tropical.
The four types of air mass are
Maritime
Continental
Polar and
Tropical
What is bok choy in a plant?
Answer: It is a whole plant.
Explanation:
It is a whole plant.
If you are interested in generally edible part it is stem.
What are the terms describes the dna–protein complexes that look like beads on a string?
Answer: The question is incomplete,below is the complete question.
What are the terms describes the dna–protein complexes that look like beads on a string?
A) Chromatin
B) 30-nanometer fibre
C) Histones
D) Nucleosome
The correct answer is option D
Explanation: A Nucleosome is the basic fundamental unit of a DNA, and the fundamental sub-unit of a Chromatin.
The Nucleosome is the basic packing unit of DNA,it is built from histone proteins. A nucleosome is made up of 8 histones proteins resembling a thread wrapped round a spool.
The smallest bundle of DNA is known as a Nucleosome,a Nucleosome is produced through interaction between DNA and histone proteins.
Lumbar vertebrae have which series of characteristics?
Etoposide is used as anti-cancer drug:_______. a) It inhibits tRNA synthestase. b) It inhibits the activity of human topoisomerase II. c) It incorporates into DNA and inhibits the function of DNA polymerase III. d) It binds to the minor groove of DNA and prevents DNA replication. e) It inhibits bacterial synthesis of folic acid.
Explanation:
(b) It inhibits the activity of human topoisomerase II.
Susan was examining a cell under the microscope and noticed the formation of a cell plate in the midline of the cell and the formation of nuclei at opposite poles of the cell. The cell under examination was most likely ______.
Answer:plant cell undergoing Cytokinesis
Explanation:
Cytokinesis is the final stage of cell division process, during which the cytoplasm splits into two and the cell divides.
In plant cells, a cell plate forms along the middleline of the cell. Then, a new nuclei form along each side of the cell plate.
Answer:
The cell under examination was most likely a plant cell undergoing cytokinesis.
Explanation:
Cytokinesis is the final step in cell division, coming right after mitosis (the process in which a eukaryotic cell divides itself into two identical daughter cells). Cytokinesis consists of the split in two of the cytoplasm.
In plant cells, cytokinesis begins when a cell plate forms along the equator, from which new cell membranes will form to wrap the new daughter cells.