Science Flashcards
Food Chain
Who eats who in an ecosystem step by step
Food Web
All the food chains in an ecosystem
Primary Succession
succession that occurs when no soil exists except for bare rock. The pioneer species is the first species to colonize these areas
Secondary succession
succession that takes place on areas that already support life
Exponential growth
Growth that occurs when there are no limiting factors, and when organisms can reproduce at a consistent rate
Logistical growth
growth that happens when there are limiting factors, occurs when a population has been growing exponentially slows or stops
Valence Electrons
single electron or one of two or more electrons in the outer shell of an atom that is responsible for the chemical properties of the atom
Valence electrons determine how reactive an atom will be.
Atoms want to have an outer shell that is full of electrons. The magic number is 8. The closer an atom is to 8 (either 1 or 2 on one end or 6 or 7 on the other), the more reactive it will be. If an atom has a full outer shell, it will not be reactive at all. These element are considered inert, meaning that they are not reactive.
Covalent
formed with atoms share electrons
Ionic
Formed when electrons are transferred from one atom to another
What elements are essential for life?
oxygen, carbon, hydrogen, nitrogen, and sulfur
What makes carbon such a good atom for life?
Carbon can readily form bonds with other atoms.
What is a hydrogen bond?
Hydrogen bond: a special type of dipole-dipole attraction between molecules, not a covalent bond to a hydrogen atom
Reactants
independent variable, the chemicals that exist in the beginning
Products
dependent variable, the chemicals that exist after the reaction are called products
What is an enzyme?
Enzymes are biological catalysts.
Substrate
the reactants of an enzyme-catalyzed reaction
Products
the result of chemical reactions
Active Site
binds to substrate
Enzyme substrate complex
binds substrate to the enzyme
How do enzymes speed up chemical reactions and how can they be affected by changes in pH and temperature?
Enzymes speed up chemical reactions as they decrease the activation energy needed to occur. Changes in pH alters the enzymes structure and changes in temperature can make the enzyme move more or less, affecting chemical reactions.
What is an organelle?
Organelles are “little organs”.
Valence Electrons
single electron or one more in the outer shell of an atom that is responsible for the chemical properties of the atom
Valence Electrons
single electron or one of two or more electrons in the outer shell of an atom that is responsible for the chemical properties of the atom
