Biology 160 exam 1

Define biology.

Biology is the scientific study of life and is the branch of science that studies living organisms and the way organisms interact with their environments.

Emergent Properties

Characteristics of a system that do not appear in any one of its component parts alone, but that appear when all parts are combined.

Viruses contain genetic information in the form of either...

DNA or RNA.

Electrons are found outside of the nucleus, in zones that are called "shells."

Electrons have almost no mass.

Hydrophobic

Hydrophobic, or water-fearing, molecules do not interact with water and are characterized by a complete lack of electronegative atoms. In aqueous solutions the hydrophobic molecules are driven together to the exclusion of water.

The atoms retain their ____ through the processes of life, even though they can be combined with other atoms in different ways.

Identity

Humans maintain a blood pH between 7.35 and 7.45. In order to maintain homeostasis, how will your body respond if your blood pH drops to 7.0?

If you blood pH is 7.0, your body will raise your pH.

Neon. Neon (Ne) has an inner shell with two electrons and a full second shell with eight electrons.

In fact, all of the elements in that column of the periodic table have full outer shells, are stable, and do not react with other elements

Any matter an organism needs but cannot make for itself is considered a _____ for that organism

Nutrient

Involves the attraction of the hydrogen with a partial positive charge to the electronegative atom with a partial negative charge.

Only hydrogen covalently bonded to an electronegative atom can participate in hydrogen bonding.

How many covalent bonds can oxygen form to fill its outer shell?

2

How many hydrogen atoms will probably form covalent bonds with oxygen?

2

Oxygen has an atomic number of eight. How many electrons are in its outermost shell?

6

Independent Variable

A cause or factor; a variable that is thought to cause another variable to change. In an experiment, an independent variable is deliberately changed in one group at the beginning of the study.

The changes in the atomic composition of a substance that occur as a result of the attraction or repulsion of two or more atoms is called a chemical reaction.

A chemical reactions produce one or more products resulting from a chemical change that transforms a set of molecules.

Organelle

A compartment inside the cells of eukaryotes that contain specific groups of macromolecules and carry out specific cellular functions.

Enzyme

A protein that speeds up the rate of chemical reactions that support life.

Evolution

A scientific theory explaining how and why genetic changes occur in populations or higher-level groups over generations of time.

Dependent Variable

An effect; a variable that is thought to change as a result or consequence of some other variable. In an experiment, a dependent variable is used to describe the result, or outcome.

Carry a negative charge, because they have more electrons than protons...

Anions...They readily take on one or more extra electrons. charge of -1.

What are the characteristics of life?

Be made of materials organized in a hierarchical pattern. Use energy and raw materials to survive. Sense and respond to changing environments and maintain internal stability, or homeostasis. Grow, develop and reproduce with the help of DNA. Evolve.

Radioactive isotopes emit energy in the form of radiation when they decay into different isotopes.

Radioactive isotopes can be used to visualize certain tissues for medical diagnosis.

Hydrophilic

Substances that dissolve in or are attracted to water. Hydrophilic (from Greek meaning "water-loving") refers to molecules that are water soluble. Ionic and polar substances are hydrophilic. That is, hydrophilic molecules contain polar functional groups that can form hydrogen bonds or ionic bonds with water.

Electronegativity

The ability of an atom to draw shared electrons closer to itself. Strongly electronegative atoms bonded to weakly electronegative hydrogen atoms, in a molecule, result in hydrogen bonding.

Atom

The basic unit of matter that cannot be further broken down without losing its unique properties. One atom consists of a dense nucleus surrounded by a cloud of electrons.

Energy

The capacity to do work or to make a change in the location, temperature, or structure of matter.

The electrons that occupy the outermost shell are called valence electrons and are the electrons that are involved in chemical bonding...

The chemical properties of an element depend mostly on the number of valence electrons.

Count the number of protons in the atom's nucleus, and that will tell you what kind of element that atom is..

The number of protons in an atom is denoted by the atomic number displayed for each element in the periodic table

Homeostasis

The tendency of organisms and cells to maintain stable internal conditions. The term comes from the Greek words homeo (same, alike) and stasis (standing).

Isotopes

Two atoms with the same atomic number , but different atomic mass Carbon-12 (the number after the hyphen, 12 in this example, indicates the atomic mass), which has 6 protons and 6 neutrons and Carbon-13, which has 6 protons and 7 neutrons are two isotopes of carbon.

four properties of water that make it such a unique and important molecule...

Water is an excellent solvent and can dissolve a wide range of substances. Water is cohesive. Water's temperature tends to remain stable. Solid water (ice) is less dense than liquid water.

Sharing of electrons is called...

a covalent bond

The first carbon actually formed two bonds with the oxygen atom; this is called...

a double bond.

When two atoms are joined by a covalent bond, the new structure that forms is called...

a molecule

Reproduction occurs when an individual organism passes on its genetic information to...

a newly independent organism, or offspring.

evolutionary processes explain both the unity and....

adaptive diversity of life

To be classified as biotic.....

all of the required conditions for life must be met or have been met in the past.

Matter is....

any substance that has mass and takes up space.

hierarchy of life consists of.....

atom, molecule, Macromolecules, cell, organelles, microorganisms. Tissues, Organs, organ system, Organisms, population, community. ecosystem. Biosphere

Chemical bonds are attractions between...

atoms that hold atoms and molecules together.

Matter is made of...

atoms.

All matter can be classified in one of two categories:

biotic (living) or abiotic (nonliving)

major elements

carbon (C), hydrogen (H), nitrogen (N), oxygen (O), phosphorus (P), and sulfur (S). These elements represent more than 95% of the mass of a cell.

Conversely, elements on the left side of the periodic table tend to give up one or more electrons and become....

cations with a positive net charge

What is the first level of hierarchical organization that possesses the emergent property of "life?"

cell

Cells typically keep their internal pH (acidity) within a narrow range. This is important because....

changes in pH can cause molecules like enzymes to change their shapes.

Other variables must be kept as similar as possible between the study groups and are called...

control variables

Ultimately, if homeostasis is not restored, an organism will....

die.

Atoms come in different types, called...

elements. Also, atoms are the smallest unit of elements.

Calories is a measure of...

energy

On the periodic table, elements to the right (with the exception of the last column) are likely to take on...

extra electrons.

Energy flows through living systems, changing...

forms as it goes

Structure determines...

function.

Life is organized into....

hierarchical levels of increasing complexity

Living organisms maintain.....

homeostasis.

Solutions are..

homogeneous mixtures.

Nonpolar molecules are hydrophobic. Examples, include...

hydrocarbons and fatty acids with their abundant nonpolar C-H bonds

Ionic substances like table salt (NaCl) are...

hydrophilic.

Polar molecules also are...

hydrophilic.

solvent: the component of the solution...

in the greatest quantity.

Life's components are....

interconnected and interdependent

Contrast to the structure formed when two atoms are joined by an ionic bond, which is called an...

ionic compound

Ionic bonds are the interactions between...

ions of opposite charges. Elements in the outer columns of the periodic table often react in this manner.

Energy flows through living systems; matter....

is recycled

The structure of something is determined by two factors....

its three-dimensional shape, and the materials from which it is made.

Matter cycles within...

living systems.

solutes: the component(s) present in...

lower quantities

Both nutrients and wastes are made of atoms; they occupy space and have....

mass

Ionic bond...

moderate strength, occurs between atoms in the same molecule (i.e., between the ions), Electrons transfer from one atom to another, resulting in a moderately strong electrostatic attraction between oppositely charged ions

By summing the atomic mass of all the atoms in a molecule, one can estimate the...

molecular mass of the molecule.

Everyday objects are mostly mixtures of....

molecules, which in turn are made up of atoms.

Scientific Method

observation, question, hypothesis, scientific experiment, and conclusion

Hydrogen bonds are not like the covalent bonds.. They do not join atoms into molecules. Instead, they are the attraction...

of an electronegative atom to a hydrogen that is covalently bonded to another electronegative atom.

water behaves the way it does because..

of the hydrogen bonds that attract water molecules to each other.

Protons and neutrons reside in the nucleus (center) of the atom and have a mass of...

one atomic mass unit (amu) each

The most stable situation for an atom is to have its..

outer shell completely filled with electrons

The most important strongly electronegative elements in biological systems are...

oxygen and nitrogen.

Bonds in which electrons are unequally shared between the atoms are called...

polar covalent bonds.

What level of organization is found within all of the other levels

population

All atoms have a nucleus, made up of...

protons (+) and neutrons(+-), and are surrounded by electrons(-).

The electron is the reactive part of the atom. The number and location of electrons determines the interactions between atoms. As you recall, negatively charged electrons are....

pulled toward the positively charged nucleus. But electrons are kept in orbit by kinetic energy. Electrons that are close to the nucleus are less energetic than those electrons farther from the nucleus.

Organisms grow, develop, and....

reproduce.

The two fundamental tenets of evolution are...

shared ancestry and natural selection.

The first shell can hold two electrons; the second and third...

shells can hold up to eight electrons.

Hydrogen bonds are fairly stable...

so quite a bit of energy is released when they are formed.

Water is the ____ and the salt is the ____.

solvent, solute

Covalent bond...

strongest bond, occurs between atoms in the same molecule, Electron pairs are shared, creating a strong bond between atoms

All organisms grow and develop. Growth is just an increase in size. In development...

structure and function change in an orderly way as an organism passes through its life cycle

Life is an emergent property, and one that appears at...

the cellular level of organization.

Molecules are not alive, but they are...

the components of life.

In order to reproduce, a virus must infect a host cell and hijack...

the host cell's machinery.

The interaction between a polar bond on water and polar bonds on hydrophilic molecules is given a special name....

the hydrogen bond, because it involves a hydrogen that forms a bridge between the two molecules.

The molecular mass or weight of a molecule is the sum of...

the individual atomic weights.

An individual's pattern of development is partly determined by genetic instructions. DNA....

the molecule of inheritance, encodes proteins and other molecules that build cells and make them work.

The atomic mass is the sum of....

the number of protons and the number of neutrons.

The cell is.....

the smallest unit that displays all of these characteristics. Also, the fundamental unit of life.

Many of the important molecules of life, like DNA, proteins, and even ordinary water, share a key characteristic:

they all form hydrogen bonds.

A key characteristic of atoms is that they are most stable when...

they have full outer electron shells

A single pair of shared electrons makes a single covalent bond. Atoms can share...

two pairs of electrons (in a double bond), or even three pairs of electrons (in a triple bond).

Hydrogen bond...

weak, Occurs between atoms in different molecules or parts of molecules, Weak electrostatic attraction between areas of molecules with opposite partial charges