Exam 1 Flashcards
What is biology
- The scientific study of life
- Biology encompasses a wide scale of size a huge variety of life, both past and present.
What are the seven common properties of life?
- ) order : All living organisms are composed of specific molecules ( Nucleic acids, Proteins, Carbohydrates, Lipids)
- ) Regulation: Regulate their internal processes.
- ) Growth and development
- ) Energy processing : Need and use energy
- ) Response to the Environment
- ) Reproduction:
- ) Evolution: Adapt/evolve as a population
Define the term science
derived from a Latin verb meaning “to know.”
– Science is a way of knowing, based on inquiry.
What two key features distinguish science from other types of inquiry?
Science depends on observations and measurements that others can verify
What are the two types of scientific approaches? What is the difference between them?
– Discovery science is mostly about describing nature.
– Hypothesis-driven science is mostly about explaining nature
What is the scientific method? Be sure you can list the steps in order.
- ) Define the problem
- )Create a good working hypothesis
- )Design an experiment to test your hypothesis
- ) predict the outcome of your experiment
- ) Test your hypothesis ( run the experiment).
- ) Examine the results and draw conclusions. Evaluate and re-work hypothesis if necessary.
Give the two requirements for a good hypothesis
– It must be testable
– It must be falsifiable
Distinguish between a hypothesis, prediction, theory, and law.
- A hypothesis needs to be tested whereas a theory has been tested and supported by evidence.
- A prediction is a statement of the expected experimental results based on the hypothesis.
- A scientific law is a description of a natural relationship or principle. Describes how things are, not an explanation of “why”
- A theory is supported by a large body of evidence from different areas of inquiry
What is a control variable? What is a positive control? What is a negative control?
Control variable receive no treatment. Positive control receives a treatment with a known result. Negative control is a group with no response to be expected.
What is the independent variable? What is a dependent variable? Standardized variables?
- Independent variables are manipulated by the scientists.
- Dependent variables are whats being measured. –
- Standardized variables ( with the exception of the variable being tested) must be kept constant.
Define the following: element, trace element, atom, isotope, ion, compound, and molecule.
-An element is a substance that cannot be broken down into simpler substances by chemical means.
- Trace elements are elements that are
– required in only very small amounts
– essential for life.
Atom: the smallest unit of matter that still retains the property of an element .
- Isotopes are alternate mass forms of an element.
- Ions are charged atoms.
- compounds (substances that contain two or more elements in a fixed ratio).
-molecule (two or more atoms held together by covalent bonds).
Describe the “anatomy” of an atom. What subatomic particles make up an atom and where are they located? You should be able to draw this out.
- Protons (positive charge): in the nucleus [central core] • -Neutrons (no charge): in the nucleus
- Electrons (negative charge): orbit the nucleus
How many electrons can the innermost electron shell hold? How many can the second electron shell hold? How many in the 3rd? What is the significance of having an unfilled outer shell? (Hint –define chemical reaction)
- First electron shell can only hold 2 electrons. 2nd shell can hold up to 8 electrons. the 3rd shell can hold up to 18 electrons.
- Atoms whose outer shells are not full tend to interact with other atoms (i.e. participate in chemical reactions).
Make sure you are familiar and can define/identify the following on the periodic chart: Element symbol, atomic number, mass number.
Element symbol in the middle, atomic number is located on the top of the element symbol, mass number is located under the element symbol.
What is an ionic bond? A covalent bond? A hydrogen bond?
- Ionic bonds are formed between oppositely charged ions
- A covalent bond forms when two atoms share one or more pairs of outer-shell electrons.
- Hydrogen bonds are weak bonds between two molecules.
What is a chemical reaction? What is the difference between a reactant and a product?
- Chemical reactions enable atoms to give up or acquire electrons, completing their outer shells.
- reactants are the starting materials
- products are the end materials
Water is a polar molecule. Describe what this means and why water is a polar molecule.
Water is a compound in which the electrons in its covalent bonds are not shared equally resulting in an uneven distribution of charge, hence a polar molecule.
What is the significance of the fact that water is a polar molecule?
Water’s polarity allows it to dissolve other polar substances very easily. The dissolving power of water is very important for life on Earth.
List the four key life-supporting properties of water. Give at least one example of each and how that property contributes to supporting life.
Properties of water:
- Water’s cohesive nature.
- molecules stick together due to hydrogen bonding. Vital for the transport of water from roots to the leaves of plants.
- Cohesion allows surface tension - Water’s ability to moderate temperature.
- Hydrogen bonds give a strong resistance to temperature change. - Ice floats.
- Life in water could not survive if bodies of water froze solid.
- Ice floats because it is less dense than liquid water. - The solvent of life.
- A solution is a liquid consisting of a homogeneous mixture of two or more substances.
What is heat? What is temperature?
- .Heat is the amount of energy associated with the movement of the atoms and molecules in a body of matter.
- Temperature measures the intensity of heat (the average speed of the molecules).
What is evaporative cooling?
is the process of removing heat from a surface due to the evaporation of water.
Define the following: solution, solute, solvent, aqueous solution.
- A solution is a liquid consisting of a homogeneous mixture of two or more substances.
- The dissolved substance is the solute.
- The dissolving agent is the solvent.
- When water is the solvent, the result is an aqueous solution.
Define pH. What is an acid? What is a base?
- We use the pH scale to describe the acidity of a solution.
- Acid: a chemical compound that releases H+ ions when placed in water.
- Base: a compound that accepts H+ ions (removes them from the solution) when placed in water.
What is a buffer?
Buffers are substances that resist pH change.