A.W )         Re: Topic 2 DQ 1

Atoms are the building blocks for elements. Atoms are made up of protons, electrons, and neutrons and come together to form elements. Some elements only have on atom naturally while most have more. Oxygen can have multiple different make ups depending on how many atoms it has. O2 is the most important but O3 can also be found. Elements cannot be broken down any further than they already are. Everything we interact with can be broken down to the basic elements. The most important elements for human life are oxygen, carbon, hydrogen,and nitrogen. The atomic number of an element tells us how many protons are in that element. Each element has a different number of protons in it with helium starting at 2 and carbon at 7. An elements mass number comes from adding up the number of protons and neutrons in an element. An elements atomic mass is close to its mass number since electrons weigh almost nothing (Simon, Dicky, Hogan, & Reece, 2016). Scientists can use all this knowledge to figure out how things work and interact with each other. The elements interact in certain ways to create molecules that we use to create new things that humans use every day.

Simon, E., Jean, D., Reece, J., & Hogan, K. (n.d.). Essential biology with physiology (5th ed.). Pearson education.

2)A.B)   Re: Topic 2 DQ 1

  • Atoms are the smallest bits of matter and are composed of particles called protons (which carry a positive electrical charge), neutrons (which carry no electrical charge.ie,neutral) and electrons (which carry a negative electrical charge). The protons and neutrons cluster together in the central part of the atom, called the nucleus, and the electrons ‘orbit’ the nucleus(means revolve around the nucleus.That path is called orbit). A particular atom will have the same number of protons and electrons and most atoms have at least as many neutrons as protons.Atoms can join together to form molecules, which in turn form most of the objects around you
  • An element is a substance that is made entirely from one type of atom. For example, the element hydrogen is made from atoms containing just one proton and one electron..
  • The atomic number is the number of protons in an element, while the mass number is the number of protons plus the number of neutrons.
  • The periodic table is listed by the atomic number.Atomic number is usually represented by the symbol ‘Z’ .Actually we can call it as the identity of an element.
  • Mass number gives the atomic weight of the element.

Mass Numbers = (Number of Protons) + (Number of Neutrons)

It is represented by the symbol A

3) J.W)  Re: Topic 2 DQ 1

Hello Alrick,

The action of atoms is really interesting and even it components; protons, neutrons and electrons. The text book states that it would take a million carbon atoms to stretch across the period at the end of a sentence. (Simon et al. 2016) It is impressive when you think about it, there had to be a million tiny dots to make up one dot and inside each dot there are even more subatomic particles, to put it simply. The periodic table contains many elements that are very useful to life today but I always wondered if there were other elements that are in the universe that man has not yet discovered and what effect they would have on our life today and our future.



Dickey, J. L., Hogan, K. A., Reece, J. B., & Simon, E. J. (2016) Campbell Essential Biology with Physiology, Fifth Edition. Published by Benjamin Cummings. Pearson Education. Retrieved from https://www.gcumedia.com/digital-resources/pearson/2015/campbell-essential-biology-with-physiology_ebook_5e.php

4) J.W ) Re: Topic 2 DQ 1

Professor and class,

An element is a pure substance that one is unable to break down into smaller substances. There are 92 naturally occurring elements.(Simon et al., 2016) Some examples of elements are carbon, nitrogen, oxygen, neon, gold and silver. Some elements naturally occur in nature and others are man-made. There are 25 essential elements that the body needs such as oxygen, hydrogen and calcium. There are also elements referred to as trace elements because the body only needs them in very small amounts and they could be acquired from the foods we eat such as iodine from iodized salt and fluorine from toothpaste or drinking water. (Simon et al., 2016) The most basic unit of matter that retains the properties of an element is the atom. Atoms of each element are unique to that element, thus hydrogen atoms differ from oxygen atoms which differ from nitrogen atoms. Atoms are extremely small but they are also made up of their own subatomic particles called, protons, neutrons and electrons. Protons are found in the nucleus of the atom and are positively charged. Neutrons, also found in the nucleus of the atom, are neutral and thus have no charge. Electrons are found in the electron cloud surrounding the nucleus and they are negatively charged.

The atomic number is the number of protons in the atom of an element, this number is unique to each element and thus allows each of them to be easily identified. This number also represents the number of electrons in an element. The same number of protons and electrons in an element cancels out, thus giving it a net charge of zero. For example, carbon has an atomic number of 6, it has 6 protons and 6 electrons in its atom. The mass number is the sum of the number of protons and neutrons. The mass number is expressed in Dalton. For example the mass number of carbon is 12 because it has 6 protons and 6 neutrons. The mass number does not only indicate the mass of the protons and neutrons but it also indicates the isotopes of that element as well.



Dickey, J. L., Hogan, K. A., Reece, J. B., & Simon, E. J. (2016) Campbell Essential Biology with Physiology, Fifith Edition. Published by Benjamin Cummings. Pearson Education. Retrieved from https://www.gcumedia.com/digital-resources/pearson/2015/campbell-essential-biology-with-physiology_ebook_5e.php


1) A.B)  Re: Topic 2 DQ 2


There is theory named as Endosymbiotic theory which was proposed by lynn margulis. With this theory she tried to explain that the eukaryotic cell organelles are actually developed from the prokaryotic cells. she described that the prokaryotes are digested by the eukaryotic cells as they were small. According to her views, the mitochondria is developed from the bacteria when it was engulfed by the eukaryotic cell whereas the chloroplast is developed from a photosynthetic bacteria. Then, later they were modified into organelles as mitochondria and chloroplast. She said that this is the reason for the presence of DNA in mitochondria and chloroplast of eukaryotic organelles because they are descendents of prokaryotic cells.

2) A.W)  Re: Topic 2 DQ 2

Mitochondria an interesting part of the human cell. Their main function of supplying energy for the cell is vital to our survival. Compared to other organelles the mitochondria has its own set of DNA. This has led scientist to wonder how it ended up in us and to try and come up with an answer. Some scientists propose the endosymbiotic theory to explain why mitochondria are so different. This theory states that today’s mitochondria descended from specialized bacteria. At some point in time the ancestor bacteria survived endocytosis (brining in of a substance into a cell forming a vesicle or a vacuole) by another prokaryote. This would have been very helpful for thatprokaryote and would have given it the edge in survival and then could reproduce more. This would have caused this trait to be passed down until it became part of humans. Over time the DNA that produces the need proteinsfor the mitochondria as disappeared making it so it could not live on its own anymore (Rice University, 2005). Through time the mitochondria have adapted to us and us to them to form an important part of our everydaylives.

Rice University. 2005. Evolutionary origin of Mitochondria. Retrieved on 1/25/21 from https://www.ruf.rice.edu/~bioslabs/studies/mitochondria/mitorigin.html

3) J.W) Re: Topic 2 DQ 2

Professor and class,

Organelles such as chloroplasts and mitochondria are thought to have descended from prokaryotic cells because of their ability to function interdependently within another larger host organism like prokaryotic cells. This process is called symbiosis. “Symbiosis is the mutually beneficial relationship between different organisms which live in close physical association. This is usually beneficial to both or they could have no effect on each other.” (Britannica, 2021) They contain their own DNA and have their own ribosomes which produce their own proteins while functioning within a larger cell. They also contain a single, circular DNA chromosome which resembles a prokaryotic chromosome. These organelles also reproduce themselves by binary fission just like prokaryotes. They do not go through mitosis instead they “pinch” into two organelles. This is why they are thought to have evolved from prokaryotes into separate organisms from a symbiotic relationship with larger host. Even though they are found in eukaryotes their origin may be from prokaryotes, their DNA tells the story. 



Dickey, J. L., Hogan, K. A., Reece, J. B., & Simon, E. J. (2016) Campbell Essential Biology with Physiology, Fifth Edition. Published by Benjamin Cummings. Pearson Education. Retrieved from https://www.gcumedia.com/digital-resources/pearson/2015/campbell-essential-biology-with-physiology_ebook_5e.php

 Encyclopaedia Britannica (2021) Symbiosis. Retrieved from https://www.britannica.com/science/ecosystem

4) is missing and I will come back later

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