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Early Life II
Integrated Science
Last time we looked at the most important elements that make up living things
on Earth, including ______, _______, ______, _______ , _______ and _____ .
We also looked at the central role that ______ plays and some of its unique
characteristics that make it ideal for things that living organisms must do.
From these few elements we have developed a large variety of living things that
seem to be much different from one another. However, on a microscopic level,
there are many similarities among all living things. This allows the question of
life’s origin to focus on the most basic one-celled organisms that have
characteristics shared by all living things. We will look now at some of these
similarities.
The first is that all living things have _________. All cells have an outer
membrane that provides a boundary with the external world. Across this
boundary selective transport of things into and out of the cell must occur. All
cells also have interiors where similar molecules and chemical reactions are
carried out.
The science that studies life on a molecular level is ____________________.
On the molecular level, there are many similarities among all living things. We
have already mentioned the basic elements from which life is formed. These
elements then combine into a few building blocks, such as _____, _____,
_____, _____, and _____ that combine into larger molecules. All of these
molecules can be classified into four types:
1.) __________________ that provide an immediate ________ source
2.) ______________ provide for energy ____________.
3.) __________________ combine to form ______________ that make
up the _____________ structures of life and catalysts that allow for
many cell functions.
4.) ______________________ that provide instructions for cellular
operations and communication within the cell and from one generation
to the next.
We will spend some time looking at general characteristics of each of these.
First are carbohydrates. These provide the energy source for our cells.
Carbohydrates are carbon atoms that combine with whole numbers of ______
molecules. The simplest reaction for forming a carbohydrate is:
________________________________________
We mentioned one important property of carbon is that it can exchange
electrons. If an element gains electrons it gains energy, if it loses electrons it
loses energy. Looking at this reaction, the charge of carbon in CO2 is ______.
The charge of carbon in CH2O is ______. Has carbon gained or lost electrons?
___________________. In gaining electrons, is it storing or releasing energy?
________________.
The gaining of electrons is referred to as _______________. An example of a
simple carbohydrate is the sugar glucose, with the formula ________________.
A glucose molecule is shown below. _____________ is another sugar with the
same formula, but a different arrangement of the atoms.
_________________ involves losing electrons. If electrons are lost, will energy
be taken in or released? ________________. When carbohydrates are
oxidized, then, they release energy. In our bodies, this release of energy is used
for activities needed in our cells. The reaction for this is:
_____________________________________________
Look again at the charges of carbon. In C6H12O6 the charge of carbon is
______. In CO2, the charge on carbon is _______. Has carbon gained or lost
electrons? ________________ Therefore, has energy been gained or released?
_______________. We mentioned that this reaction is important in our bodies.
When we breathe, what molecule do we need to take in that is one of the
reactants in this equation? ____________ Without taking in oxygen for more
than a few minutes we will die. When we breathe out, what molecule do we
remove as waste from our body that is on the product side of this reaction?
__________
We can see, then, that carbohydrates are vital to us, and this reaction is
continuously going on in our bodies.