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anyanavicka [17]
3 years ago
6

Some cells will undergo programmed death when _____.

Biology
2 answers:
Natalka [10]3 years ago
6 0
Would it be b because diseased cells will die.

Levart [38]3 years ago
4 0

Answer:

B. Diseased

Explanation:

The process of programmed cell death ensures that the older, damaged and diseased cells are removed from the body organisms and are replaced with new healthy cells. Each cell type has specific life span after which they undergo cell death. However, infected and diseased cells also experience programmed cell death so as to prevent the spread of infection.

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Which statement best describes a pattern shown in the data?
Rashid [163]
A is correct (ur welcome)
5 0
3 years ago
Indicate whether the following outcomes of cell division are observed in mitosis only, meiosis only, or both mitosis and meiosis
serious [3.7K]

Answer:

A. Both in mitosis and meiosis (II)

B. Mitosis

C. In both

D. Meiosis

E. Mitosis

Explanation:

Prior to every case of cell division in both mitosis and meiosis, the cell always ensures to duplicates its contents including its chromosomes. In both cases of cell division, the sister chromatids separates, apart from in meiosis I where homologous chromosomes separates to opposite poles. Only one cellular division occurs in mitosis which is involved in the growth and development of the diploid individual but in meiosis, two divisions takes place in the gametes (both male and female) to ensure that the haploid number of chromosomes is transfered from both parents each to the offspring ensuring a constant diploid offspring. Thus a diploid parent cell always produces a haploid daughter cell in the gametes during meiosis. In mitosis, the daughter cells are always identical to the parents cells.

4 0
3 years ago
A cell membrane has a double layer of molecules. These molecules are made up of a phosphorus-containing “head” and two long, fat
podryga [215]
D I believe, in the picture that is attached explains

6 0
3 years ago
Are viral infections curable? Why or why not?
Anna11 [10]

Answer:

no.

Explanation:

Viruses, on the other hand, are not cellular. We can't kill them simply by disrupting their cells. They are infective nucleic acids which cannot replicate outside of living cells. They must invade a human cell to reproduce, because they cannot produce energy or synthesize molecules on their own. Some viruses replicate inside human cells and then bud off from the human cell inside an "envelope" made from the human cell's own membrane, which helps them evade the immune system on their way to infecting another human cell. Many viruses are protected by protein capsids, which are extremely protective--unlike a bacterial cell wall or membrane, the virus doesn't have to be alive inside the capsid or exchange nutrients and waste with the environment across the capsid; the capsid is merely there to protect the nucleic acid of the virus.

Viruses need to match some sort of receptor in order to gain entry into human cells, and in some viruses, this receptor is one of the few good targets for drug therapy; however, unlike antibacterials, the drug will only work for that particular virus/receptor, because each virus uses a different receptor.

Viruses spend time inside human cells, which protects any outer antigens from some of the aspects of the immune system. There are times when viruses are especially vulnerable during replication, but there are reasons they are harder than bacteria to target with these antireplication drugs: 1) unlike for most bacteria, the drugs need to be small enough to enter the human cell where the virus is replicating, 2) unlike for most bacteria, the drugs can't simply target a protein shared by most viruses; furthermore, many viruses hijack human proteins which cannot be targeted. Overall, there are comparatively few antiviral drugs compared to antibiotics because of the huge difficulty in obtaining selective toxicity. And 3) most drugs available target a certain step of viral replication for a certain family of viruses; however, by the time the patient shows symptoms, the virus has already created countless copies of itself or become latent in human cells, and at that point it is too late for most of the antiviral drugs to be super helpful since they target the replication itself. Even when a good antiviral drug is developed, most of them work only against a single species (or at best, a family) of viruses, which is not the case for most antibiotics.

Many viruses don't spread in ways where they can easily targeted (Polio moves from the GI tract to lymph nodes and then to the blood stream on it's way to the spinal cord to cause paralysis; it is vulnerable to the immune system in vaccinated individuals while it is forced to travel in the blood. In contrast, some viruses like rabies, herpes, and varicella-zoster spread through neurons in order to evade the immune system. Other viruses form syncytia because they travel directly from cell to cell). Also remember that some viruses integrate themselves into human DNA and remain latent for long periods of time, which prevents them from being cleared by drugs or the immune system. The human immune system does have its ways of dealing with viruses, which I can get into in greater detail in another post. For certain viruses, the only way we have to treat them is to use interferons to ramp up the immune system (a very unpleasant therapy which must often be maintained for very long periods of time).

One of the reasons that vaccines for some viruses are not effective is that oftentimes, a live (attenuated) vaccine cannot be made for those certain viruses since the reversion mutation rate is too high to provide an acceptable risk; for many viruses, only killed strains can be used, if at all. Without a live attenuated virus strain multiplying inside cells, certain critical aspects of the immune system are not activated against these certain viruses. In cases where killed viruses are able to be used as vaccines, the protection is lesser (for instance, no type-switching to IgA antibodies which would be more effective than IgM) and shorter-lived.

7 0
3 years ago
Read 2 more answers
Finches that live in an isolated area with limited access to seeds and water is an example of what mechanism in Darwin's theory
Brums [2.3K]

Answer:

c. Limits on population growth

Explanation:

Darwin was heavily influenced by Malthusian theory of how population growth was influenced by growth limits. For Darwin, the population growth of species of living beings would be influenced by the limits imposed by the environment in which these species live, through the amounts of natural resources available to the population.

Thus, Darwin concludes that when the environment allowed an abundance of natural resources, such as water and food, the population of living beings would tend to grow more, however, when natural resources are limited, the population would grow less. This is called "population growth limits".

An example of this can be seen in the question above, where finches that live in an isolated area have limited access to seeds and water.

4 0
3 years ago
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