Answer:
I hope this helps!!
Explanation:
The existence and perpetuation of life depend on the functioning of cells and their divisions. There are two important processes of cell division, which are inextricably linked with each other to maintain the progress of life. These processes are Mitosis and Meiosis.
After fertilization, when a sperm cell and an egg cell unite to form a new organism, it is expected to carry a double number of chromosomes because both the parents contribute their whole number of chromosomes as appropriate for the respective species. But the process of meiosis prevents the doubling of the chromosomes.
It reduces the total number of chromosomes in half so that the offspring (newly formed cell) can retain the same number of chromosomes as the parents. On the other hand, mitosis facilitates in forming of two daughter cells from a single cell where each new cell resembles the parent cell in every respect. Unlike meiosis, mitosis involves duplithe cation of chromosomal pairs, which is essential for cellular reproduction, especially during growth.
The Mechanism of Mitosis:
A specific process is required for forming two daughter cells out of a mother cell. This process is known as mitosis and it is usually divided into four stages, prophase, metaphase, anaphase, and, telophase. In some cases, it is convenient to designate the transition from prophase to metaphase by the name of prometaphase. However, the whole process of the cycle of mitosis is a continuous one.
1. Prophase:
At the beginning of the prophase stage, the cell prepares itself to divide the chromosomes. It is the resting stage when the nucleus becomes a little larger. It also involves the condensation of the previously diffuse, invisible, or dispersed threads into visible chromosomes.
Each chromosome is optically double, which is composed of two identical and closely parallel strands or chromatids lying throughout their length. A chromosome bears a constriction or a narrow region of attachment to the spindle, which is called a centromere.
Constrictions other than the centromere are sometimes called ‘secondary constrictions’.At prophase s,tage the centromere and secondary constrictions look alike, but by metaphase, this distinction is clear because they develop entirely different relations to the spindle.
In this stage (prophase) the outlines of the chromatids present a slightly irregular woolly or hairy appearance. They do not, in general, show a series of granules (chromo-meres) as are seen at the meiotic prophase, and probably this is a real difference between the two. By the end of the prophase, the woolly appearance almost disappears and a smooth outline is visible.
2. Premetaphase:
At the end of the prophase, the nuclear membrane usually disappears and this stage may be defined as the period of spindle formation. During this stage, the chromosomes give an impression of struggling and pushing among themselves too to reach the equator of the developing spindle. The spindle is relatively a solid gelatinous body. It is composed almost entirely of protein with a very small amount of RNA.
The centrosome seems to act as an organizer of the spindle. The centrosome is the differentiated region of cytoplasm containing centriole, which is a minute granule present just outside the nuclear membrane. After the disappearance of the nuclear membrane, the centriole is doubled and the two centrioles move apart from each other to form the poles of the spindle.
The spindle fibers are probably bundles of protein molecules. A distinction may be made between continuous fibers and chromosomal fibers. The continuous fibers run from pole to pole whereas the chromosomal fibers connect the centromeres to the poles.
In the case of bipolar spindles, the equatorial plane is located perpendicular to the long axis, which is the midway between the poles. As the prometaphase proceeds, the chromosomes arrange themselves with their centromeres, on the equatorial plane of the spindle. It is the most dynamic stage which gives rise to a relatively static Metaphase.
describe how the surface of the earth moves, the way it moves and the effects of movement
Answer:
tectonic plates
Explanation:
and lose very very slowly but it moves towards each other or farther apart because there you are what you called Divergent tectonic plates convergent tectonic plates and contraction tonic plates
which two mammals do you think is the least closely related? why?
Answer:
Chimpanzees and man
Explanation:
Ever since researchers sequenced the chimp genome in 2005, they have known that humans share about 99% of our DNA with chimpanzees, making them our closest living relatives.
But there are actually two species of apes that are this closely related to humans: bonobos (Pan paniscus) and the common chimpanzee (Pan troglodytes). This has prompted researchers to speculate whether the ancestor of humans, chimpanzees, and bonobos looked and acted more like a bonobo, a chimpanzee, or something else—and how all three species have evolved differently since the ancestor of humans split with the common ancestor of bonobos and chimps between 4 million and 7 million years ago in Africa.
The international sequencing effort led from Max Planck chose a bonobo named Ulindi from the Leipzig Zoo as its subject, partly because she was a female (the chimp genome was of a male). The analysis of Ulindi's complete genome, reported online today in Nature, reveals that bonobos and chimpanzees share 99.6% of their DNA.
Which element is found in nucleic acids but not in amino acids
a. carbon
b. hydrogen
c. nitrogen
d. phosphorus
Answer:
d. phosphorus
Explanation:
Phosphorus is the only element that is identified with nucleic acids.
Hope This Helped
Where is the nucleus usually located?
A. outside of the cell
B. in the center of the cell
C. moves between cells
Answer:
B
Explanation:
usually in the center . depends on what cell prokaryotic or eu
Several bird species feed in a certain species of tree. each bird species feeds in a different part of the tree. which factor are the species of birds responding to in the environment?
a.) symbiosis
b.) competition
c.) parasitism
d.) omnivores
Competition factor are the species of birds responding to in the environment. Thus, the correct option is B.
What is competition?If numerous bird species eat on the same tree species, there will be fierce competition for food. As a result of the competition, each species will seek out a certain portion of the plant to feed on, most likely the part of the plant where it will be easiest to outcompete the competitors for food.
As a result, we may deduce that the right response is "They have evolved to diverse niches as a result of competition."
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Answer:
simply jus competition
Why isa DNA replication regarded as semi conservative?
Answer:
each helix that is created contains one strand from the helix from which it was copied.
Explanation:
What causes the doldrums to be calm winds?
o a. mountain ranges provide friction, slowing the doldrums.
b. trade winds from the north and south collide, pushing the air up.
c. earth revolves around the sun, keeping doldrums stationary.
d. frequent storms bring heavy precipitation, pushing the air down.
Earth revolves around the sun, keeping doldrums stationary causes the doldrums to be calm winds. Thus, the correct option is C.
Why are the doldrums so calm?The Intertropical Convergence Zone, also known as the doldrums or calms by sailors due to its constant lack of wind, is the area where the northeast and southeast trade winds meet. It encircles the Earth near the thermal equator, however its exact location changes with the seasons.
The sunlight beams down directly on the area around the equator, the Doldrums are caused by solar radiation from the sun. Instead of blowing horizontally, this heating causes the air to warm and climb straight up. As a result, there is little or no wind for weeks at a time.
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HELP!! Rank the following forms of water from most common (1) to least common (4) on Earth.
(a) ground water
(b) rivers and lakes
(c) glaciers
(d) oceans and seas
d\b\c\a
Match each field of study with its main focus.
Anthropology
?
Hydrology
?
Meteorology
?
Geophysics
?
Human culture
Water
Inside of Earth
Climate
A cross is performed between a bird that is homozygous for red feathers and a bird that is homozygous for blue feathers. Purple offspring result due to incomplete dominance. Then, two of the purple offspring are crossed. What proportion of the offspring from the second cross will be purple?.
The proportion of the offspring from the second cross that will be purple is 1/2 because parents are heterozygous.
What is incomplete dominance?In genetics, incomplete dominance makes reference to the phenomenon where both alleles are expressed in heterozygous individuals.
In this case, parents are heterozygous and therefore they can produce three types of offspring.
In this case, the genetic crosses include
Parental lines (P) AA x aaFilial 1 (F1) 100% AaFilial 2 (F2) generationA a
A AA Aa
a Aa aa
In conclusion, the proportion of the offspring from the second cross that will be purple is 1/2 because parents are heterozygous.
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The proportion of the offspring from the second cross will be purple is 1/2, i.e. 50% of the offspring will be purple.
What is Incomplete Dominance?Incomplete dominance may be defined as a phenomenon in which the F1 hybrid exhibits the characters intermediate for the parental genes.
Due to the heterozygous nature of both parents in the F1 generation, they produce offspring in the genotypic and phenotypic ratio of 1:2:1.
The Punnett square for this cross is described below:
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This technique allowed multiple peoples DNA to be compared to look for similarities and differences in order to solve crime
DNA Elimination
DNA Examination
DNA Fingerprinting
DNA Sequencing
DNA Fingerprinting allowed multiple people's DNA to be compared to look for similarities and differences in order to solve crimes (Option C).
What is DNA Fingerprinting?DNA Fingerprinting is a molecular biology technique used to compare the genetic material of different samples.
This technique (DNA Fingerprinting) can be used in order to identify a person in a criminal case.
In conclusion, DNA Fingerprinting allowed multiple people's DNA to be compared to look for similarities and differences in order to solve crimes.
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Plants growing in the dark start to fall over because they can no longer
support their own weight. Students want to find out why this is happening.
Which of these is a good hypothesis for an investigation of the problem?
OA. The plants need to absorb glucose from the soil so they can have
more energy.
OB. The plants should start using protein in order to support their
bodies.
OC. The plants need sunlight so they can produce more cellulose for
support.
OD. The plants need more water in order to keep their cellulose from
breaking down.
Answer: B
Explanation: its ez
Explain how a stent can be used to prevent a heart attack
Use the drop-down menus to answer the questions. the principle of dominance is a inheritance pattern. it states traits that are mask the traits that are .
The principle of dominance is a Mendelian inheritance pattern. It states traits that are dominant mask the traits that are recessive.
What is genetics?Genetics is the study of inheritance, the foundation of genetics was laid by Gregor Mendel. According to Mendel, the units of inheritance were called factors and are today called genes.
The principle of dominance is a Mendelian inheritance pattern. It states traits that are dominant mask the traits that are recessive.
Missing parts:
The principle of dominance is a ______ inheritance pattern.
It’s states traits that are ______ mask the traits that are______
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Answer:The principle of dominance is a
✔ Mendelian
inheritance pattern. It states traits that are
✔ dominant
mask the traits that are
✔ recessive
.
Explanation:
Which of the following is a characteristic of a scientific theory?
a
It explains how nature works.
b
It is based on a single experiment.
c
It should not be possible to replicate its results.
d
It should not be possible to replicate its observations.
Answer:
explains how nature works
Explanation:
Which method provides the most accurate evidence for scientists to use when determining evolutionary relationships between two species of animals?
O Identifying fossil patterns in rock strata where the animals live
O Looking for similar vestigial structures in both species of animals
O Comparing genetic sequences in the animals using samples of DNA
O Looking for similarities in the coloration and eating habits of the answer
How does the circulatory and respiratory system work together?
which of the following statements best captures the main point of paragraph 4? a cell is the smallest unit that is truly alive. all cells are surrounded by a cell membrane. cytoplasm is gell-like material that fills all cell. plant cells have cell walls
Answer:
all cells are surrounded by a cell membrane
Albinism is a recessive trait. A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation). What is the probability that their first child will be an albino
Answer:
use the generation tree starting by the grandparents as first generation and the parents as second generation until the child as third generation
Renewable energy
do you think renewable energy is gaining attention and progress is being made to increase the use of harnassing natural renewable power?
what do you think are the barriers that are preventing us from utilizing more renewable energy sources?
Answer:
yes it is doing
Explanation:
Renewable sources are those which can use again and again . We should use them to protect our natural resources
What could be a good effect of a mutation?
A. DNA does not function properly.
B. DNA is destroyed.
C. Less variety in a population.
D. More variety in a population.
Answer:
The answer is D
Explanation:
because there different type which creates variety
Substance A has a specific heat capacity of 0.452 J/g℃, Substance B has a specific heat capacity of 2.64 J/g℃. If an equal mass of both substances at room temperature was placed in a heated room, which substance would you expect to heat up faster?
Substance A or B?
The substance would you expect to heat up faster is Substance A, which has a specific heat capacity of 0.452 J/g℃.
What is specific heat capacity?The specific heat capacity is the amount of heat necessary to elevate 1 degree 1 kg of the substance. Its unity is J/gºC. We can calculate the heat that changes the temperature of a substance by the equation:
Q = mcΔT
Where Q is the heat, m is the mass, c is the specific heat capacity, and ΔT is the change in the temperature.
Thus, Substance A, has a specific heat capacity of 0.452 J/g℃.
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what are the functions of plasma membrane??
btw hii
Answer:
Hi
Explanation:
It separates the content of cell from their external environment.
It controls the entry and exit of materials in nd out of cell
What is a control group?
A. An experiment where you only test two variables at a time.
B. An experiment that you don't change any variables.
C.An experiment where you only make quantitative observations.
D An experiment where data is collected.
Answer:
B. An experiment that you don't change any variables.
Answer:
B. An experiment that you don't change any variables.
Explanation:
why viruses are kept in border line of living and non-living things.
Which of the following is a way that minerals are used?
a. industry
b. construction
c. technology
d. all of the above
Please select the best answer from the choices provided
O
Answer:
maybe its are technology??
What do we need from producers in order
to sustain all living organisms on Earth?
A. Producers need to harness solar energy.
B. Producers need to release energy.
C. Producers need to release carbon dioxide.
D. Producers need to break down energy from food. What is the answer
Answer:
d
Explanation:
Which sentence describes a river?
A. It contains water that is always in motion.
B. Many unusual organisms live there due to its unique water
chemistry.
C. It protects land from flooding by absorbing the force of ocean
storms.
O D. As sediments build up, it can turn into a marsh.
Answer:
I believe the answer is A; It contains water that is always in motion.
Explanation:
Can someone help me please?
The kind of population growth depicted by the graph is exponential growth.
What is exponential population growth?It is a kind of population growth that takes place in an environment where the population has no limiting factors. In order words, there are unlimited resources without any hindrance to the growth of the population.
Such a population grows rapidly as soon as it is able to adapt to its environment and continue growing at maximum biotic potential.
A graphical illustration of the exponential growth usually forms a J shape curve.
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I really need help my grades go in tonight and this is my last day you will get full points
Answer:
the flat horizontal lines indicate phase change
Explanation:
As the substance changes phase from solid to liquid and liquid to gas, the temperature remains contant due to latent heat energy.
Energy is being used to break the intermolecular bonds during phase change, therefore there is no change in temperature.