Biology II - Exam 1

What is an organism?

All forms of life.

What is taxonomy?

Grouping of species based on common ancestry.

What are the bio themes?

Organization, Information, Energy and Matter, Interactions, Evolution.

What are the levels of organization from largest to smallest?

Biosphere, Ecosystems, Communities, Populations, Organisms, Organs, Tissues, Cells, Organelles, Molecules.

What is the relationship between structure and function?

Function provides insight into structure and organization.

What is the cell?

Smallest unit of organization of life.

What are the characteristics of eukaryotic cells?

Has membrane-enclosed organelles, largest of which is the nucleus.

What are the characteristics of prokaryotic cells?

Simpler and smaller, does not have a nucleus or membrane-enclosed organelles.

What is genetic information?

Genes are the units of inheritance, cells have chromosomes containing DNA.

How do living organisms use energy?

They use energy from the environment to maintain internal order.

Give examples of energy usage in living organisms.

Cellular respiration, metabolism, photosynthesis.

What are feedback regulations?

Output of a process regulates that very process.

What is the most common form of feedback regulation in living organisms?

Negative feedback, where the response reduces the initial stimulus.

What is positive feedback?

A process that once started, doesn't stop.

What is evolution?

The process of change in all forms of life over generations.

What is the biosphere?

The largest level of organization that encompasses all ecosystems.

What is an ecosystem?

A community of living organisms and their physical environment.

What is a community?

A group of living organisms in a particular area.

What are the three domains of life?

Bacteria, Archaea, Eukarya

What is Domain Bacteria?

Unicellular prokaryotes in diverse environments

What is Domain Archaea?

Unicellular prokaryotes in extreme environments

What is Domain Eukarya?

Unicellular and multicellular eukaryotes

What is a scientific discipline?

Observation, identification, investigation, and explanation of natural phenomena

What is the scientific method?

Observation, hypothesis, prediction, experimentation, conclusion

What is a hypothesis?

Possible explanation for an observation, must be tested for validity

What is deductive reasoning?

General to specific, based on established principles

What is inductive reasoning?

Specific observations to broader generalizations and theories

What is a controlled experiment?

Comparison between experimental group and control group

What are experimental variables?

Features or quantities that vary in an experiment

What is the independent variable?

Manipulated by the researchers

What is the dependent variable?

Predicted to be affected in response

How do scientists collaborate within a lab?

Students, postdocs, technicians, and PI work together

What are atoms?

Smallest units of matter that form all chemical substances.

What are compounds?

Substances formed by the bonding of two or more elements.

What are the elements of life?

Carbon, hydrogen, oxygen, and nitrogen make up 96% of living matter.

What are trace elements?

Elements required by an organism in only minute quantities.

What are subatomic particles?

Protons, neutrons, and electrons that make up atoms.

What is the overall charge of an atom?

No net charge, as protons and electrons are present in equal numbers.

What is an isotope?

Atoms of the same element with different numbers of neutrons.

What is the atomic number?

Number of protons in an atom, also equal to the number of electrons.

What is the unit of measurement for atomic mass?

Dalton.

How do radioisotopes lose energy?

By emitting subatomic particles and/or radiation

How many electrons can each shell hold?

2 electrons

What is the characteristic of energy in shells?

Shells have characteristic energy

What is a covalent bond?

Electrons are shared to fill the shell

What are the two types of covalent bonds?

Polar covalent or nonpolar covalent

What is a hydrogen bond?

Attraction between a hydrogen atom from one polar molecule and an electronegative atom from another molecule

What is an ionic bond?

Electrons are transferred, forming ions that are attracted to each other

What is the definition of covalent bonds?

Atoms share a pair of electrons

What type of atoms form covalent bonds?

Atoms with unfilled valence electron shells

What is the characteristic of covalent bonds?

Strong chemical bonds, shared electrons belong to each other

What are polar covalent bonds?

Form between atoms of different electronegativity, creating a polarity across the molecule

What are nonpolar covalent bonds?

Form between atoms with similar electronegativity, no charge difference across the molecule

What is a molecular formula?

Contains chemical symbols of elements in the molecule, with subscripts indicating the number of each atom

What is a compound?

Any molecule composed of two or more elements

What are ions?

Atoms or molecules that have gained or lost one or more electrons

What are weak bonds that can form and break easily?

Hydrogen bonds

What is the definition of chemical reactions?

When one or more substances change into other substances

What are the reactants and products in a chemical reaction?

Reactants -\> Products

What are the properties of chemical reactions?

Source of energy, use enzymes as catalysts, occur in liquid (water)

Are most chemical reactions reversible?

Yes

What is hydrogen bonding in water?

Uneven charge, oxygen negative, hydrogen positive

What are the properties of water?

Cohesive behavior, ability to moderate temperature, expansion upon freezing, versatility as a solvent

How does cohesion of water molecules contribute to plant transportation?

Counteracts gravity, helps transport water and nutrients

What is adhesion?

Attraction between water and other substances

How does water moderate temperature?

Absorbs and releases heat, slight change in temperature

What determines the properties of water?

Amounts of solutes

How are hydrophilic substances characterized?

They readily dissolve in water and have ionic and/or polar covalent bonds.

How are hydrophobic substances characterized?

They do not dissolve in water and are nonpolar, such as hydrocarbons and oils.

What are amphipathic molecules?

Molecules that have both polar (hydrophilic) /ionized and nonpolar (hydrophobic) regions.

What is the structure of a micelle?

Polar (hydrophilic) regions are at the surface, while nonpolar (hydrophobic) ends are oriented toward the interior.

What is concentration?

The amount of a solute dissolved in a unit volume of solution.

What are acids?

Substances that increase the H concentration of a solution.

What are bases?

Substances that reduce the H concentration of a solution.

What happens when strong acids and bases dissolve in water?

They completely dissolve in water.

What is the pH scale?

A scale used to measure the acidity or basicity of a solution.

What pH range is considered acidic?

pH 6 or below.

What pH is considered neutral?

pH 7.

What pH range is considered basic?

pH 8 or above.

Why do organisms need buffers?

To minimize changes in concentrations of H+ and OH- in a solution.

What do most buffers contain?

A weak acid and its corresponding base, which combine reversibly with H+ ions.

What is organic chemistry?

Study of carbon-containing compounds

Why is carbon versatile?

Can form four bonds, leading to diverse molecules

What are hydrocarbons?

Organic molecules with only carbon and hydrogen

What are the properties of hydrocarbons?

Nonpolar, hydrophobic, poorly soluble

What are isomers?

Compounds with same formula but different structures/properties

What are structural isomers?

Isomers with different covalent arrangements of atoms

What are cis-trans isomers?

Isomers with same bonds but different spatial arrangements

What are enantiomers?

Mirror image isomers

What are chemical groups?

Attached groups that give organic molecules unique properties

What are some examples of chemical groups?

Functional groups like hydroxyl, carbonyl, amino, etc.

What is the role of oxygen and nitrogen in organic molecules?

Form polar bonds, making molecules hydrophilic and soluble in water

What is the role of carbon in organic molecules?

Forms the backbone and can make up to four bonds

What is the significance of isomerism in organic chemistry?

Different structures lead to different functions and properties

What is the relationship between cis and trans isomers?

Mirror images of each other

What is the significance of enantiomers?

Different spatial arrangement affects biological activity

How do chemical groups contribute to the properties of organic molecules?

They determine the molecule's reactivity and function

What are functional groups?

Components of organic molecules involved in chemical reactions.

How do functional groups contribute to a molecule's properties?

The number and arrangement of functional groups give each molecule its unique properties.

Give an example of a functional group and its role.

Amino group acts as a base.