2. Identify and describe three types of stress.

Describe three observations an astronaut might make while viewing Russia at night.(Site 1)

olga55 [171]

One observation would be the physical size of Russia compared to other countries, despite a lack of visible borders from space. In addition, part of Russia's outline would likely be obscured by the various clouds and objects in the stratosphere; this would allow the astronaut to view potential cloud and weather patterns on earth. Also, an astronaut could see outlines of Russia's geography such as mountain ranges.

4 0

3 years ago

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1) How is DNA condensed to form a chromosome?

Bumek [7]

Answer:

1) DNA is wrapped around histone proteins to form chromatin

2) The genes are the functional units, the segments between them are used for regulation

3) The genetic code is the language used, gene expression is how the cell uses the information, the activity of the genes.

Explanation:

1) DNA forms a DNA/protein complex called chromatin. It does this by wrapping around histone proteins. These histone proteins are usually present in the form of a nucleosome, which is a unit containing 2 copies of 4 histones (H2A, H2B, H3 and H4). The chromatin fibre at its most compact forms tightly coiled structures called chromosomes. These structures are only present during cell division. When the cell is in interphase (i.e. not dividing), the chromatin is not as tightly condensed, and instead the chromatin is more relaxed to allow the genes within to be expressed.

2) Genes are the functional units that the cell uses to make RNA and protein. The genes are first transcribed into RNA, which is processed and then translated into a polypeptide chain, which forms a complete protein that performs activities in the cell/tissue/organism. However, the whole genome does not form genes, there are regions that do not correspond to a gene. These regions are called "non-coding DNA" or sometimes even "junk DNA". However, that does not mean that these regions do not have important roles. The role of this DNA is usually in regulating the activity of the nearby genes. This DNA might contain important regulatory sequences such as promoters/enhancers/silencers that control how the gene is used by the cell, by for example, recruiting transcription factors or silencing proteins.

3) The genetic code is the language used by the cell. It explains how the cell can transcribe the information in the DNA, to RNA, process the RNA, and then translate the RNA into a polypeptide, and eventually a mature protein. In contrast, gene expression represents how the cell actually uses this information. Not all the genes are transcribed at the same time, instead, the activity of genes is carefully controlled to produce appropriate gene expression patterns, allowing the cell to properly perform its functions. Gene expression is hugely different between cells in an organism, for example the gene expression patterns of a muscle cell will be hugely different to that of a blood cell.

5 0

3 years ago

What kinds of environmental problems result from population growth in (a) developing countries and (b) developed countries? Whic

Alecsey [184]

Answer:

Environmental problems result from population growth in:

a) Developing countries-

Air pollution due to burning of fuels and wood.
Water and soil pollution due to improper waste disposal.
Improper resource use due to illiteracy etc.

b) Developed country-

Overuse of natural resource
Deforestation.
Air pollution due to increased number of industries and automobiles.etc

Explanation:

A developing country is the one which is economically backward and are still combating poverty and illiteracy.

The major reason behind the population growth is illiteracy and unsafe coitus.

This results in unwanted childbirth.

The second reason is the want for earning members to support the family.

Increasing population creates an outstanding demand of resources and creates a pressure on environment.

More and more fuels are burned and hence add up to air pollution.

Improper disposal of waste is also a major issue in these countries as most of the people being illiterate are unaware of proper ways of disposing such waste.

A developed country is at the epitome of economic growth.

The major reason behind the population growth in these country is the immigration of people from developing countries.

Being economically advance , these countries can afford best of technologies that make the utmost use of resources available.

Increase demands of settlements, industries and resources has lead to clearing of large forest lands and deforestation.

Industries and automobiles has added up to the air pollution too.

According to me the effect of population growth in developed countries is a greater threat because these lead to overexploitation of resources by technology. more the population will grow the demand for development will also grow. Thus, this is quite difficult to control.

In case of developing countries, proper education and training will create difference to a greater extent.

4 0

3 years ago

Where is the 1% of Earth’s liquid freshwater located?

ANTONII [103]

The anwser of d I’m sure of it

5 0

2 years ago

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Summarize the process of fertilization and implantation.

Aneli [31]

The process of fertilization involves the deposition of sperms into the vagina to the egg cell during sexual intercourse. Sperms make their way towards the cervix and uterus, and eventually goes to the fallopian tubes. Only a few hundred will remain as they interact with the egg through the use of their heads and movement patterns.

The process of implantation happens when the embryo, the fertimized eggs develops inside the fallopian tube after three days, and then travels to the uterus.

7 0

3 years ago