Hierarchy of Life
Atom → Molecule → Organelle → Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere
Cells:
-
Prokaryotic – No nucleus (bacteria)
-
Eukaryotic – Has nucleus + organelles (plants, animals)
Control Group
Used as a benchmark to measure the results of the experiment
Comparing Technology with Science
Life is organized in a hierarchal manner
The steps of the scientific method:
1- Observation
2- Questioning
3- Hypothesis
4- Experiment
5- Conclusion
Living organisms are composed of matter
Matter is composed of chemical elements
Element: Cannot be broken down to something else
Only 92 exist in nature (Ex: Iron)
Changing the compound:
Adding salt to water doesn’t change the compound
Adding one more Oxygen does!
This is because adding to the compound changes the ratio that essentially gives that compound its identity
Atoms consist of protons, neutrons, and electrons
Neutrons: no charge (0)
Exists inside of the nucleus
cannot be predicted unlike electrons and protons
It’s contribution:
Contributes to the atomic mass
Protons: positive charge (+)
Exists inside of the nucleus
It’s contribution:
Contributes to the atomic mass
acts as the ID of the atom (changing it changes the identity of the atomic )
Electrons: negative charge (-)
Exists outside of the nucleus, and moves around it
It’s contribution:
It doesn’t change the atomic mass
It contributes to the atom’s electrical charge
Vital role in forming and breaking of bonds
Different isotopes of an element:
Same number of protons
Different number of neutrons
An isotope of an element is a variant that has the same amount of protons but a different number of neutrons
Reactive bonds
Stable bonds
Def a question in the exam:
Given the periodic table and asked to know the name and the symbol of the atom, and calculate the electrons, protons, and neutrons it consists of
class exercise
Ar = stable