Biology
Biology Exam Review
Unit One – Biochemistry
What is an isotope?
Isotope
- An isotope is all atoms of the same element that have the same number of protons, but they may have different numbers of neutrons in the nucleus.
- This means that all atoms with the same atomic number can have different atomic masses.
- Because they have the same number of protons and electrons, they behave exactly the same in chemical reactions.
Radioisotope
- The nuclei of some isotopes of an element are unstable and tend to break down, or decay giving off particles of matter that can be detected as radioactivity
Example – Carbon has three isotopes.
- The decay process transforms an unstable, radioactive isotope into an atom of another element.
Example – As Carbon-14 decays, one neutron splits into a high energy electron and a proton.
- The isotope then has 7 neutrons, 7 electrons, and 7 protons which is characteristic of the most common form of the element nitrogen.
- Thus the decay of carbon-14 transforms the carbon atom into nitrogen-14, a nitrogen atom.
- Radioactive decay continues at a steady rate, with a constant proportion of radioisotope atoms breaking down during a given time interval.
- The radiation may damage molecules in living cells, however, some are useful in geological process to determine the age of organic material or in medical applications.
Radiocarbon Dating – http://www.youtube.com/watch?v=2io5opwhQMQ
- Used to determine how old living things are.
- Nitrogen in the atmosphere is hit by cosmic rays and converted to a carbon-14 atom.
- The atmosphere is made up of a bunch of carbon dioxide. Most of the carbon is going to be carbon-12. And occasionally the carbon will be carbon-14.
- Plants such as wheat take in the carbon-14 through a process called photosynthesis.
- The carbon-14 ends up in the cereal we eat and eventually ends up in our bodies.
- The amount of carbon-14 in the atmosphere is equal to the amount in our bodies as long
Unit One – Biochemistry
What is an isotope?
Isotope
- An isotope is all atoms of the same element that have the same number of protons, but they may have different numbers of neutrons in the nucleus.
- This means that all atoms with the same atomic number can have different atomic masses.
- Because they have the same number of protons and electrons, they behave exactly the same in chemical reactions.
Radioisotope
- The nuclei of some isotopes of an element are unstable and tend to break down, or decay giving off particles of matter that can be detected as radioactivity
Example – Carbon has three isotopes.
- The decay process transforms an unstable, radioactive isotope into an atom of another element.
Example – As Carbon-14 decays, one neutron splits into a high energy electron and a proton.
- The isotope then has 7 neutrons, 7 electrons, and 7 protons which is characteristic of the most common form of the element nitrogen.
- Thus the decay of carbon-14 transforms the carbon atom into nitrogen-14, a nitrogen atom.
- Radioactive decay continues at a steady rate, with a constant proportion of radioisotope atoms breaking down during a given time interval.
- The radiation may damage molecules in living cells, however, some are useful in geological process to determine the age of organic material or in medical applications.
Radiocarbon Dating – http://www.youtube.com/watch?v=2io5opwhQMQ
- Used to determine how old living things are.
- Nitrogen in the atmosphere is hit by cosmic rays and converted to a carbon-14 atom.
- The atmosphere is made up of a bunch of carbon dioxide. Most of the carbon is going to be carbon-12. And occasionally the carbon will be carbon-14.
- Plants such as wheat take in the carbon-14 through a process called photosynthesis.
- The carbon-14 ends up in the cereal we eat and eventually ends up in our bodies.
- The amount of carbon-14 in the atmosphere is equal to the amount in our bodies as long