This occurs when two sperm nuclei reach the interior of a female gametophyte, where one sperm will fertilise the egg cell to form a zygote, whereas the other usually fuses with the binucleate central cell, forming a primary endosperm cell, effectively constituting an organism separate from the growing embryo. Approximately 70% of angiosperm species have polyploid endosperm cells which are typically triploid (containing three sets of chromosomes), but can vary widely from diploid(2n) to 15n.
The group of enzymes able to relax supercoils in dna is called
Which of the following is not a piece of molecular evidence supporting the endosymbiotic theory?
The mitochondria and chloroplasts are much different in structure than bacteria. Hence the correct option is a.
One piece of molecular evidence supporting the endosymbiotic theory is the similarity between the DNA of mitochondria and chloroplasts and that of bacteria. This similarity suggests that mitochondria and chloroplasts may have originated from free-living bacteria that were engulfed by ancestral eukaryotic cells and formed a symbiotic relationship.
Additionally, the presence of ribosomes in mitochondria and chloroplasts that resemble those found in bacteria further supports this theory. Moreover, the mechanism of division by fission, which is similar to bacterial reproduction, observed in some organelles like mitochondria and chloroplasts provides further evidence for their bacterial origins.
However, the structural differences between mitochondria, chloroplasts, and bacteria do not directly support the endosymbiotic theory but rather suggest evolutionary adaptations that have occurred over time. Therefore, option A is not a piece of molecular evidence supporting the endosymbiotic theory. Hence the correct option is a.
Complete question:
Which of the following is not a piece of molecular evidence supporting the endosymbiotic theory?
A. The mitochondria and chloroplasts are much different in structure than bacteria.
B. Ribosomes of some organelles are like that of those found in bacteria.
C. Some organelles divide by fission just like bacteria.
D. Mitochondrial and chloroplast DNA is similar to bacterial DNA.
2.) The seafloor holds promise as a source of many natural resources, including valuable metals. As demand for natural marine resources increases, mining these resources from the seafloor also increases. One concern of seafloor mining is the disruption of the seafloor habitat. Which of the following describes the most likely impact of seafloor mining on the surrounding marine environment?
A.) Alteration in seafloor sediments rich in carbon would cause loss of species and an unbalanced population in marine food webs.
B.) Increased levels of metals in the ocean would result in decrease of marine bivalves due to weakened shells.
C.) Methane gas would pollute the marine environment and cause an overabundance of bacteria that feed on it.
D.) Nonrenewable resources in the marine environment would become depleted and affect the balance of the ecosystem.
Answer: A.) Alteration in seafloor sediments rich in carbon would cause loss of species and an unbalanced population in marine food webs.
Explanation:
The seafloor mining will have a drastic impact over the sea ecosystem. The mining process will expose the partially decomposed organic matter to the sea water. This will result in the increase in abundance of the organic carbon in the sea water. This will readily absorbed by the aquatic plants but the increase in abundance will likely to kill sea animals because carbon is the waste material discharged by the organisms and oxygen is the basic requirement for all the cells of the body. This will negatively influence the populations of the marine food webs.
In some species, young individuals float freely as plankton while mature members are fixed on the seafloor. this is an effective strategy because
Which is not correctly paired concerning parasympathetic outflow? which is not correctly paired concerning parasympathetic outflow? the glossopharyngeal nerve innervates salivary glands the oculomotor nerve innervates smooth muscle in the eye that allows for pupil constriction the nerves coming from the thoracic region innervate stomach and liver the nerves coming from the sacral section innervate lungs and heart the vagus nerve stimulates many glands in the head like lacrimal and salivary glands?
The breathing center in the brain is most sensitive to the ________________. concentration of carbon dioxide in the lungs amount of oxygen in the cells concentration of oxygen concentration of carbon dioxide in the blood
What is a metabolic pathway? see section 16.1 (page 337) . view available hint(s) what is a metabolic pathway? see section 16.1 (page 337) . a process that results in mutations in genes a series of steps that convert a precursor to arginine a series of steps only found in neurospora crassa a series of steps in which enzymes work one at a time to convert a compound to a related compound?
The answer is a ‘series of steps in which enzymes work one at a time to convert a compound to a related compound’. The intermediate products of metabolic pathways are called metabolites. An example of a metabolic cycle is the Glycolysis and Krebs cycles. The product in each step of the metabolic pathways becomes the substrate of the next step in the pathway. There are two types of metabolic pathways; anabolic and catabolic
The scientific name for a white oak is Quercus alba; the scientific name for a red oak is Quercus rubra. What does this tell you about the organism? A. White oaks are grouped in the genus Quercus. B. Red oaks are grouped in the genus alba. C. Red oaks are grouped in the species Quercus. D. White oaks are grouped in the same species category as red oaks.
Answer:
rong
Explanation:
Functions of the cell membrane include physical isolation of the cell from its surroundings, regulation of exchange, structural support, and which other function? functions of the cell membrane include physical isolation of the cell from its surroundings, regulation of exchange, structural support, and which other function? binding and delivery of oxygen extracting energy from the environment for cell survival radiation of heat to prevent protein denaturation and cell stress. communication between the cell and its environment
Which subatomic particle contains the energy stored in chemical bonds? isotope , neutron , electron , proton
For the eighth observation (i=8), identify the animal phylum, xi, and yi.
Why a flash of green light might cause the Flubber to become so energetic
Answer:
A flubber is a rubber like polymer that absorbs and amplifies energy. A flubber absorbs energy from a light source and electrons present in it are excited in order to emit light of higher wavelength. The green light absorbed by the flubber to emit longer wavelength of light emitting more energy.
Flubber is a slime-like polymer material that is made up of cross-linked boron with polyvinyl alcohol. It is used for educational experiments and leisure activities.
Flubber absorbs and amplifies energy. It absorbs energy from the source and reflects it.
The electrons present in the polymer gets excited and emit a wavelength of a high order.
The green lights excite the flubber material and make them energetic which leads to the emission of high wavelength.
Therefore, the green light makes the flubber more energetic.
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Explain how trees can be produced and yet the smallest trophies level in a pyramid of numbers
Sugar is a compound of which Of the following?
A) carbohydrates
B) lipids
C) nucleic acids?
Which organism is most closely related to canis familiaris?
Alarm, resistance, and exhaustion are all considered part of the body's ___________response.
adrenaline
stress
panic
autonomic nerve
im not sure if its autonomic nerve or stress,
Which of the choices below is the parent cell for all formed elements of blood?
a. megakaryocyte
b. hemocytoblast
c. polymorphonuclear cell
d. natural killer cell
e. myeloid cell?
Answer:
b. hemocytoblast
Explanation:
Hemocytoblasts are the pluripotent stem cells present in the red bone marrow and have the ability to give rise to all types of cells present in the blood. For example, the formation of red blood cells from hemocytoblast includes myeloid stem cell, proerythroblast, intermediates stages of accumulation of hemoglobin and enucleation and finally the red blood cells. Likewise, hemocytoblast can also from various white blood cells and platelets from different cell pathway.
The parent cell for all formed elements of blood is the hemocytoblast, also known as a hematopoietic stem cell.
Option (b) is correct.
Hemocytoblasts are multipotent cells found in the bone marrow that have the ability to differentiate into various types of blood cells. They give rise to all the different types of formed elements found in blood, including red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).
Megakaryocytes are responsible for producing platelets, but they are derived from hemocytoblasts themselves. Polymorphonuclear cells and natural killer cells are specific types of white blood cells that are formed through the differentiation of hemocytoblasts within the bone marrow. Myeloid cells refer to a group of cells that include erythrocytes, granulocytes, monocytes, and platelets, all of which originate from the hemocytoblast.
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What do biologists call groups of cells that are specialized to secrete substances outside the cells?
Is balamuthia mandrillaris a public health concern worldwide?
Which of the following is a feature of the sun's radiation?
It cannot travel through air.
It cannot travel through vacuum.
It is made up of rays of the same frequency.
It is made up of rays of different wavelengths.
The common ancestor of the protostomes had a coelom. what does this suggest?
The client is admitted with paroxysmal supraventricular tachycardia at a rate of 140 beats per minute. the client's blood pressure is 110/55 mm hg, and the client is asymptomatic except for a "fluttering feeling" in the chest. which treatments should the nurse be prepared to administer
Why do you think macarthur chose inchon as his landing place?
The diagonal arrow of a cladogram shows us that we are moving _________ in time.
The diagonal arrow of a cladogram shows us that we are moving forward in time.
Are carbohydrates used for long term energy storage?
All living things are made of organic compounds which contain the element A) carbon. B) hydrogen. C) oxygen. D) phosphorus.
A black guinea pig crossed with an albino guinea pig produces 12 black offspring. when the albino is crossed with a second black one, 7 blacks and 5 albinos are obtained.
Which of these allow nutrients to diffuse form the central canal to all the osteocytes within an osteon?
Mr. jones has a large kidney stone that is obstructing the flow of urine in his left kidney, resulting in kidney enlargement and backing up of urine into his ureter. this is known as:
Which factor would not increase the production of glucose by photosynthesis in plants?
Lack of water would not increase glucose production by photosynthesis in plants because water is crucial for the light reactions to produce NADPH and ATP, which are needed in the Calvin cycle to synthesize glucose. Insufficient water impacts the entire photosynthetic process, leading to decreased glucose production.
Explanation:A factor that would not increase the production of glucose by photosynthesis in plants is a lack of water. Water is essential for the light reactions of photosynthesis, where water molecules are split to form oxygen, electrons, and protons. These electrons and protons are then used to generate NADPH, which, along with ATP produced in the light reactions, is used in the Calvin cycle to synthesize glucose. Without sufficient water, these processes can't occur optimally, and the production of glucose by photosynthesis would decrease.
Regarding the statement about how an increase in temperature causing faster diffusion of CO2, and consequently, a potential increase in the rate at which plant leaves lose CO2; if all other conditions are favorable for photosynthesis, the increased loss of CO2 may lead to reduced availability of CO2 for the Calvin cycle. This can result in a decrease in photosynthesis (as per option d.), since there would be less CO2 to be fixed into glucose.
The products of the Calvin cycle are glucose and other sugar molecules as well as the regeneration of the molecule RuBP which is necessary for the cycle to continue.
If a plant lacks a photosystem II complex due to a mutation, it would not be able to initiate the light-dependent reactions of photosynthesis, leading to a failure to produce the essential compounds like ATP and NADPH required for the Calvin cycle, thus disrupting the synthesis of glucose.
Plants that lack sunlight or sufficient water would not be able to perform photosynthesis efficiently, which would impact not only the plant's survival but also the organisms that rely on those plants for food, leading to broader ecological consequences.
Exposure to only red light can still support photosynthesis, although the rate may vary depending on the specific species of plant and its adaptations to light conditions (as per options b. and c.).
Factors not increasing photosynthesis include a lack of water or insufficient CO₂, both crucial for the Calvin cycle. A mutation removing photosystem II would inhibit photosynthesis, and only red light exposure can also affect the rate of photosynthesis. Plants without sunlight or water would produce less glucose, impacting dependent organisms.
Explanation:Factors that do not increase the production of glucose by photosynthesis in plants include a lack of water or inadequate carbon dioxide (CO₂). A lack of water would prevent hydrogen ions (H+) and NADP+ from forming NADPH, which is essential for the Calvin cycle of photosynthesis. Not enough CO₂ would limit the number of carbon molecules available to be fixed into glucose during the Calvin cycle. Additionally, an increase in temperature might lead to a faster loss of CO₂ from plant leaves, affecting the Calvin cycle by slowing it down due to insufficient carbon to fix in the system. This could potentially lead to lower glucose production if light and water are adequate.
The products of the Calvin cycle, which depend on carbon fixation, are carbohydrates and regenerated RuBP (ribulose bisphosphate), which is critical for the cycle to continue. If a plant had a mutation that eliminated its photosystem II complex, it would not be able to split water molecules to generate oxygen, hydrogen ions, and electrons essential for the formation of NADPH and ATP, thus hampering the photosynthetic process and preventing glucose production.
With only red light exposure, the rate of photosynthesis in a plant could potentially decrease or follow a complex pattern where it decreases and then increases, depending on the specific wavelength of the red light and the plant's individual response to it. For plants lacking sunlight as an energy source or sufficient water, photosynthesis would be inhibited, reducing glucose production and potentially affecting those organisms that rely on plants for survival.