Answer:
LEARNING OBJECTIVES
Identify important checkpoints in cell division
Explain how errors in cell division are related to cancer
The length of the cell cycle is highly variable, even within the cells of a single organism. In humans, the frequency of cell turnover ranges from a few hours in early embryonic development, to an average of two to five days for epithelial cells, and to an entire human lifetime spent in G0 by specialized cells, such as cortical neurons or cardiac muscle cells. There is also variation in the time that a cell spends in each phase of the cell cycle. When fast-dividing mammalian cells are grown in culture (outside the body under optimal growing conditions), the length of the cycle is about 24 hours. In rapidly dividing human cells with a 24-hour cell cycle, the G1 phase lasts approximately nine hours, the S phase lasts 10 hours, the G2 phase lasts about four and one-half hours, and the M phase lasts approximately one-half hour. In early embryos of fruit flies, the cell cycle is completed in about eight minutes. The timing of events in the cell cycle is controlled by mechanisms that are both internal and external to the cell.
Explanation:
Regulation of the Cell Cycle by External Events
Both the initiation and inhibition of cell division are triggered by events external to the cell when it is about to begin the replication process. An event may be as simple as the death of a nearby cell or as sweeping as the release of growth-promoting hormones, such as human growth hormone (HGH). A lack of HGH can inhibit cell division, resulting in dwarfism, whereas too much HGH can result in gigantism. Crowding of cells can also inhibit cell division. Another factor that can initiate cell division is the size of the cell; as a cell grows, it becomes inefficient due to its decreasing surface-to-volume ratio. The solution to this problem is to divide.
Whatever the source of the message, the cell receives the signal, and a series of events within the cell allows it to proceed into interphase. Moving forward from this initiation point, every parameter required during each cell cycle phase must be met or the cycle cannot progress.
Regulation at Internal Checkpoints
It is essential that the daughter cells produced be exact duplicates of the parent cell. Mistakes in the duplication or distribution of the chromosomes lead to mutations that may be passed forward to every new cell produced from an abnormal cell. To prevent a compromised cell from continuing to divide, there are internal control mechanisms that operate at three main cell cycle checkpoints. A checkpoint is one of several points in the eukaryotic cell cycle at which the progression of a cell to the next stage in the cycle can be halted until conditions are favorable. These checkpoints occur near the end of G1, at the G2/M transition, and during metaphase
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Describe how new hair fibers are formed
Answer:
Taking nutrients from the dermal papilla, the hair bulb generates new hair cells. As these cells move up through the hair root, they mature through a process called keratinization, fill with fibrous protein and lose their nucleus.
Explanation:
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A cell is placed in a hypertonic solution. Which will most likely occur as homeostasis is maintained in the cell?
A.
The cell will gain ATP molecules.
B.
The cell will gain water.
C.
The cell will lose water.
D.
The cell will lose sodium ions.
Answer:
B the cell will lose water
Explanation:
Because of the hypertonic solution water will move on the concentration gradient leaving the cell and entering the solution. Thus the cell looses water.
When a cell is placed in a hypertonic solution, it will most likely lose water (Option C) as homeostasis is maintained in the cell.
What is homeostasis?Homeostasis is the ability of an organism or a system to maintain a relatively stable internal environment, despite changes in external conditions. It is a key aspect of biology that helps living organisms survive in their environment. Homeostasis is maintained through a series of physiological processes that regulate different aspects of an organism's biology, such as temperature, fluid balance, and pH
A hypertonic solution is one that has a higher concentration of solutes (e.g. salts) outside the cell compared to inside the cell. This creates an osmotic pressure gradient, which draws water out of the cell and into the solution in an attempt to balance the concentration of solutes on both sides of the cell membrane. As a result, the cell will shrink and lose water.
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The photo shows a process called mosquito fogging.
What is one purpose of mosquito fogging?
O A To prevent people from getting stek from undercooked meat
Te treat people who have infeetiens caused by Viruses
e. Te eamy waste away from eities so people dont get siek
D. To kill insects that commonly spread diseases to people
Answer:
D. To kill insects that commonly spread diseases to people
Answer:
D. To kill insects that commonly spread diseases to people
Explanation:
Fogging is a technique used for killing insects that involves using a fine pesticide spray (aerosol) which is directed by a blower.
explain exocrine system??
Answer:
Exocrine: Pertaining to the secretion of a substance out through a duct. The exocrine glands include the salivary glands, sweat glands and glands within the gastrointestinal tract. Exocrine is as opposed to endocrine which refers to the secretion of a substance (a hormone) into the bloodstream.
When do populations increase?
Answer:
c
Explanation:
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John Ray introduced a new method of grouping by similarities in appearance.
True
False
Answer:
true
Explanation:
3. The picture on the right shows the sequence of nitrogen bases on part
of a DNA strand. Which string of letters below represents the nitrogen
bases in the order they would pair up with this part of the DNA strand?
A. C-T-G-C-A
B. G-A-C-G-T
C. A-G-T-A-C
(the picture is T-C-A-T-G)
Answer: C
Explanation: Thymine pairs with Adenine and Cytosine pairs with Guanine.
A large group of seals from Prince Harold Coast Antarctica has emigrated to Oates Coast Antarctica How will this impact the remaining seal population Prince Hard Coast
A The Prince Harold population will decrease
B. The Prince Harold population will increase
C The Prince Harold population will be reduced to zero
DThis will have no impact on the Prince Harold population
Answer:
B
Explanation:
Because now it’s a larger group
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Explain how sexual and asexual reproduction both lead to better evolutionary fitness.
Answer:
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Explanation:
To get diversity in individuals, genetic differences are required, and different phenotypes must be expressed. Since sexual reproduction is more conducive to driving evolution than asexual reproduction, much more genetic diversity is available for natural selection to work on. Evolution can happen over time.
During the day when the sun is shining the ground gets warm mainly as a result of
Answer:
The ground becomes warm by the effect of sunlight.
Explanation:
This is because the sun radiates huge amount of heat from its surface. This heat reaches the earth in the form of light energy. This heat is absorbed by the earth's surface and makes it warm.
Put "Polygenic Traits" in a sentence
Answer:
Polygenic traits are controlled by a number of separate genes.
Hope it helps! :D
Answer:
Polygenic traits are controlled by a number of separate genes
Explanation:
Hope this helps
What determines the code, or information, of a DNA molecule?
A - the structure of nitrogen bases
B- the color of nitrogen bases
C- The sequence (order) of nitrogen bases
D- the frequency of nitrogen bases
Answer:
C- The sequence (order) of nitrogen bases
Explanation:
please answer please, If we have a male hemophiliac (such as Leopold) marry a normal female, is there any way to have sons who have hemophilia? Provide a justification for your response.
which ecosystem has the greatest biological diversity and therefore the highest sustainability
Answer:
Tropical rain forests on land and coral reefs in marine systems are among the most biologically diverse ecosystems on Earth and have become the focus of popular attention.
Explanation:
definitely D because a rainforest is extremely vast when it comes to different species
Answer:
Species richness is greatest in tropical ecosystems. Tropical rain forests on land and coral reefs in marine systems are among the most biologically diverse ecosystems on Earth and have become the focus of popular attention.
What makes echinoderms unique to all other animals? (think of systems/structures they
have that no other animal has!)
If the sphincter allows any leakage from the stomach, some of this acid might move back into the esophagus, causing
1. Heartburn
2. Saliva
3. Constipation
4. Diarrhea
The diploid cells of a radish plant contain 18 chromosomes. How many chromosomes are in a radish plant's haploid cells?
Answer:
9
Explanation:
The diploid chromosome number for a radish is 18 and the diploid chromosome number for cabbage is also 18. The haploid number for these species is nine. Therefore, the gametes of the radish and cabbage contain nine chromosomes.
How does the oyster population
In the Chesapeake Bay ecosystem affect the floating to sea floor ratio of algae
populations
Answer:
Analysis of the data shows that the ratio of floating algae to sea floor algae dramatically increased at the same time that oysters were removed from the Bay. ... (It is also possible to infer from the graph that high floating algae levels led to the decline in oysters.
Answer: Analysis of the data shows that the ratio of floating algae to sea floor algae dramatically increased at the same time that oysters were removed from the Bay. ... (It is also possible to infer from the graph that high floating algae levels led to the decline in oysters.
II. Which animal is the top predator in many wetlands?
A. Raccoons
B. Alligators
C. Snakes
D Owls
Answer:
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Only a few natural elements have a greater density than gold. They are: ??
15 POINTS AND BRAINLIEST FOR CORRECT ANSWERS!!!
Plutonium
Neptunium
osmium
let me know if it's correct or not, these were the only ones I could think of.
Few natural elements have a greater density than gold are plutonium, neptunium, and osmium.
What is an element?
An element is define as a type of substance that is impossible to break into smaller pieces by the help of chemical process. There are several rules that should be followed at the time of assinging name of the elements. The first rule is name of the element is not a proper noun. The second rule is the symbols of the element that must be of one or more than one symbol.
Density is define as the mass per unit volume it means that 1 kg mass present in 1 meter cube is called density, density is also states that the how compact an material.
Mathematically
Density = mass/volume
S.I unit of density is kg/m^3
Density is higher in solid as compare to liquid and density of liquid is higher than gas so density is in order of SOLID>LIQUID>GAS. So we know that solid is compact in nature as compare to liquid and gas.
Therefore, Few natural elements have a greater density than gold are plutonium, neptunium, and osmium.
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Two plants were being tested for growth. Both were given water and proper soil, etc. However, one was placed in the closet, and one was placed in the window sill. Why did the one in the closet die?
Question 4 options:
It did not have chloroplasts.
It was not around other plants.
It did not receive sunlight.
It was not around people enough.
Answer:
It did not receive sunlight.
Explanation:
Plants need sunlight to survive along with water and nutrients from the soil.
The golden-cheeked warbler and the black-throated green warbler look nearly identical to each other. What type of information could be used to determine if the birds are separate species? Select all that apply. The birds breed with each other where their territories overlap. The birds breed with each other where their territories overlap. The birds show differences in mating songs and behaviors. The birds show differences in mating songs and behaviors. The birds do not breed with each other where their territories overlap. The birds do not breed with each other where their territories overlap. The birds compete for food and nesting sites. The birds compete for food and nesting sites.
Answer:
The birds do not breed with each other where their territories overlap.
Explanation:
The correct answer would be that the birds do not breed with each other where their territories overlap.
A species consists of organisms that are phenotypically similar and are capable of mating to produce fertile progeny.
Hence, the first thing to establish that two organisms are not of the same species is the inability to breed with each other. If an eventuality occurs and they are able to breed, the resulting progeny would be invalid.
Therefore the fact that the golden-cheeked warbler and the black-throated green warbler do not breed with each other where their territories overlap is enough information to determine that the birds are separate species.
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What specifically makes up a protein.
Answer:
The building blocks of proteins are amino acids, which are small organic molecules that consist of an alpha central carbon atom linked to an amino group, a carboxyl group, a hydrogen atom, and a variable component called a side chain
Explanation:
:)
Explanation:
The building blocks of proteins are amino acids, which are small organic molecules that consist of an alpha (central) carbon atom linked to an amino group, a carboxyl group, a hydrogen atom, and a variable component called a side chain.
Which of the following is a true
statement about queen ants?
a. They have shorter lifespans than other types of ants.
b. They are the only females that live in ant colonies.
c. They are the only types of ants that can lay eggs.
d. They are the only ants that protect defenseless
larvae.
Answer:
c. They are the only types of ants that can lay eggs.
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Spend one minute writing an explanation of
the FUNCTION of enzymes. YOU MUST USE
THE WORDS CATALYST, ACTIVATION
ENERGY, RECYCLABLE
Answer:
Enzymes help speed up chemical reactions in the human body. They bind to molecules and alter them in specific ways. They are essential for respiration, digesting food, muscle and nerve function, among thousands of other roles.
What is the function of an enzyme? They allow chemical reactions to occur at normal body temperature fast enough to sustain life. They reduce the activation energy needed to start a chemical reaction.
There are four steps in the process of an enzyme working. (1) An enzyme and a SUBSTRATE are in the same area. The substrate is the biological molecule that the enzyme will work on. (2) The enzyme grabs onto the substrate with a special area called the ACTIVE SITE.
There are four steps in the process of an enzyme working. (1) An enzyme and a SUBSTRATE are in the same area. The substrate is the biological molecule that the enzyme will work on. (2) The enzyme grabs onto the substrate with a special area called the ACTIVE SITE.
Enzymes create chemical reactions in the body. They actually speed up the rate of a chemical reaction to help support life. The enzymes in your body help to perform very important tasks. These include building muscle, destroying toxins, and breaking down food particles during digestion.
If the amount of CO2 in the atmosphere increases, do we expect to record an increase or decrease in the pH of the ocean? Why?
Answer:
As the atmospheric concentration of carbon dioxide above water increases, the acidity of the water will increase causing the pH to decrease.
What is involuntary muscle
Answer:
involuntary muscles can be defined as the muscles that functions or contracts without conscious control and are controlled by the autonomic nervous system.
Answer:
involuntary: A muscle movement not under conscious control e.g. the beating of the heart.
What are Hox genes?
A. genes that can produce large changes in adult animals during the embryological development
B. genes that are most often used to calculate a molecular clock
C. genes that have never gone through the process of crossing over
D. duplicate genes that are always responsible for speciation
Answer:
a
Explanation:
I haven't heard of them
Answer:
A.
Explanation:
Hox genes encode and correct positions of body structures making sure they form in the correct places in the body.
1 point
Which explanation best identifies the relationship between mitosis and
reproduction? *
Mitosis is a form of sexual reproduction because the daughter cells form from one
single parent cell.
Mitosis is a form of sexual reproduction because the daughter cells are genetically
different from the parent cell.
Mitosis is a form of asexual reproduction because the daughter cells form a new
nuclear membrane after reproduction.
Mitosis is a form of asexual reproduction because the daughter cells are genetically
identical to the parent cell.
How are environmental issues and food production related?
Answer: Food consumption and production have a considerable impact on the environment. Food production contributes
Explanation: , for example, to climate change, eutrophication and acid rain, as well as the depletion of biodiversity. It is also a considerable drain on other resources, such as nutrients, land area, energy, and water.