Midterm Practice (AP Biology)

What is a compound?

Any substance consisting of two or more different elements in a fixed ratio; A substance consisting of atoms or ions or two or more elements that are chemically bonded together

Define element.

Any substance that cannot be broken down into other substances by ordinary chemical means

A rain forest primate called an aye-aye has a long middle finger that it uses to probe for insects in cracks and crevices in tree bark. This connection between structure and function develeoped gradually as a result of

natural selection

In an ecosystem, there are many interactions among organisms, and between organisms and their _______ environment

nonliving

The exchange of matter and energy in an ecosystem involves a complex web of ______________

relationships

Plants absorb mineral nutrients from the ____

soil

What is adhesion?

the binding of a cell to another cell, or a cell to a surface via specific cell adhesion molecules; joining of two different substances due to attractive forces that hold them; keeps the water drops on the surfaces of leaves and flowers in place; fibrous bands that form between tissues and organs, often as a result of injury during surgery

What is cohesion?

the binding together of alike molecules; water being attracted to another water molecule—also causes water molecules to form drops. Helps to explain the occurrence of surface tension and capillary action

Define carbon skeleton

the chain of carbon atoms in an organic molecule ex butane and isobutane

What is an atomic number?

the number of protons normally found in an atom of a given chemical element. The higher the atomic number, the heavier the atom is. In a neutral atom, the number of protons and electrons is the same

What is life's chemistry tied to?

Water.

What makes some isotopes radioactive?

When any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays.

Distinguish between ionic bonds, nonpolar covalent bonds, polar covalent bonds, and hydrogen bonds, noting their relative strengths and where they form

covalent = bond between atoms formed by sharing a pair of valence electrons, strong chemical bond, can form between two nonmetals; structural formula = formula which represents the atoms + bonding within a molecule (e.g. H — H) The line represents a shared pair of electrons; molecular formula = formula which indicates the number and types of atoms (e.g. H2); nonpolar covalent bonds = covalent bond formed by an equal sharing of electrons between atoms. Occurs when electronegativity of both atoms is about the same (e.g. CH4). Molecules made of one element usually have nonpolar covalent bonds (e.g. H2, O2, Cl2, N2); polar covalent bonds = covalent bond formed by an unequal sharing of electrons between atoms that have different electronegativities. Shared electrons spend more time around the more electronegative atom; ionic bond = can form between nonmetals and metals, bond formed by the electrostatic attraction after the complete transfer of an electron from a donor to an acceptor. Acceptor attracts electrons because it is much more electronegative than the donor atom

There are many interdependencies in an ecosystem. Prokaryotes and fungi play an important role in the ecosystem primarily because they

decompose the remains of dead organisms

_______ such as bacteria and fungi convert dead matter to simpler nutrients

decomposers

Extrapolating from general premises to specific results is a kind of logic called

deductive reasoning

What is a molecule?

A cluster of atoms held together by bonds

What is more common than a pure element?

A compound

What is a double bond?

A covalent bond resulting from the sharing of two pairs of electrons; eg., H2C==CH2 (ethylene)

What is an organelle?

A functional component of a cell

What is a tissue?

A group of similar cells with a specific function

What is a cell?

A living unit, separated from its environment by a membrane

What is a buffer?

A solution that resists a change in pH when acids or bases are added. Solutions that are acidic contain high concentrations of hydrogen ions (H+) and have pH values less than seven; a solution containing either a weak acid and a conjugate base or a weak base and a conjugate acid, used to stabilize the pH of a liquid upon dilution

What is a base?

A water-soluble compound that reacts with acid and forms salt; a substance capable of donating a pair of electrons to an acid; substance that accepts protons (hydrogen ions); has a pH higher than seven

What is a community?

All the organisms in a particular ecosystem

What is population?

All the organisms of one species in a given area

What is the smallest unit of matter that still maintains the properties of an element?

An atom

____ has characteristics that result from the organization of its component _____

An organism...organ systems

__________ are consumers: they eat plants and each other

Animals

Charge of protons, neutrons, and electrons?

(+), (-/+), (-)

What is acid precipitation?

(as rain or snow) having increased acidity caused by environmental factors (as atmospheric pollutants). Occurs when industrial gas emissions (especially sulfur dioxide and nitrogen oxides) combine with water

What is an acid?

A chemical substance that neutralizes alkalis, dissolves some metals, and turns litmus red; typically a corrosive or sour-tasting liquid of this kind. Has a pH of less than seven

Biologists group living things into _ domains

3

About how many elements in nature? What is unique about them?

92; only a few exist in a pure state

What is an organ?

A body structure consisting of several tissues, performing particular functions

What is a trace element?

A chemical element present only in minute amounts in a particular sample or environment. Essential, but only in a minute quality

About how many elements are essential to life?

25

What is a biosphere?

All environments on Earth that support life

Describe matter.

All living things are composed of matter; matter is anything that occupies space and has mass

What is an Ecosystem?

All of the organisms of a particular area plus the nonliving environment that surrounds them

What makes radioactive isotopes dangerous and what are their uses?

Dangers: can cause cancer in humans and other living things. can also cause burns; Uses: to see how medications are absorbed and transported throughout the body; nuclear power plants; mantles for gas and kerosene lamps (Thorium); smoke detectors; nuclear weapons; bullets and other shells; watch lights; treatment of cancer

Define carboxyl group

Carboxylic acids are polar. Because they are both hydrogen-bond acceptors (the carbonyl -C=O) and hydrogen-bond donors (the hydroxyl -OH), they also participate in hydrogen bonding. Together the hydroxyl and carbonyl group forms the functional group carboxyl.

Define denaturation

Denaturation is a process in which proteins or nucleic acids lose the quaternary structure, tertiary structure and secondary structure which is present in their native state, by application of some external stress or compound such as a strong acid or base, a concentrated inorganic salt, an organic solvent

What is at the base level of the biological hierarchy?

Chemicals

Rabbits function as ________ in an ecosystem

Consumers

Why are certain chemicals added to the human diet?

To help preserve food, to make it look better, or to make it more nutritious.

What can trace elements sometimes be used to prevent?

Disease

The information in ___ underlies all of the properties that distinguish life from nonlife

DNA

Explain how electron configuration of an atom influences its chemical behavior.

Electron configuration = distributions of electrons in an atom's electron shells. If an atom does not have enough electrons to fill all shells, the outer shell will be the only one partially filled. Chemical properties of an atom depend on the number of valence electrons. Valence electrons = electrons in the outermost energy cell; octet rule = rule that a valence shell is complete when it contains eight electrons; incomplete valence = chemically reactive; atom with same number = similar chemical behavior

Define a compound and explain how compounds in living organisms are different from compounds in nonbiologicalmaterials

In 1828, German chemist Friedrich Wohler discovered that vitalism was untrue, showing that living organisms had one thing in common: they all contain carbon. They may also contain other elements like hydrogen, oxygen, and nitrogen. Wohler disproved vitalism by creating urea. A compound is a substance consisting of atoms or ions or two or more elements that are chemically bonded together.

Define dehydration reaction

In chemistry and the biological sciences, a dehydration reaction is usually defined as a chemical reaction that involves the loss of a water molecule from the reacting molecule. Dehydration reactions are a subset of condensation reactions.

Define carbonyl group

In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups.

How and why is iron added to the human diet?

Iron is added to the diet to help increase oxygen flow. It is added into food.

How and why is fluoride added to the human diet?

It is often mixed in with municipal water and dental products to help reduce tooth decay.

How and why is iodine added to the human diet?

It is often mixed in with the common substance, table salt (NaCl) to help prevent against thyroid problems such as goiter.

What are contained in an atom's nucleus?

Neutrons and Protons

What is an organ system?

Organs that work together to perform a particular function

What are the four elements that make up most of the weight of living organisms, and what percentage to they make up?

Oxygen, Carbon, Hydrogen, and Nitrogen; 96%

Almost all of the organisms in Kingdom _______ are photosynthetic

Plantae

________ are the main producers in a forst

Plants

What do atoms consist of?

Protons, neutrons, and electrons

What is an isotope?

Same kind of element. Contains the same number of protons, but a different number of neutrons.

What is the scientific name of table salt?

Sodium Chloride (NaCl) - Composed of equal parts of both Na and Cl

What is an atom's mass number?

Sum of the number of neutrons and protons in the nucleus; approximately equal to the atomic mass.

What causes the formation of organisms?

The gradual arrangement of chemicals into higher and higher levels of biological hierarchy`

What can chemicals be defined as?

The stuff that makes up our bodies, the bodies of other organisms, and the physical environment

All organisms have what in common?

They respond to stimuli; they store genetic information in DNA molecules; they utilize energy; they reproduce

A crop scientist noted that, over a period of 10 years, a beetle species that feeds on rice gradually became resistant to insecticide. Which of the following best explains this in terms of natural selection

Those beetles with natural resistance to the insecticide had the most offspring

Decomposers _________ chemical nutreints

recycle

A bacterium and an amoeba are placed in different domains because

a bacterial cell is much simpler

What is a covalent bond?

a bond between two or more atoms that is provided by electrons that travel between the atoms nuclei, holding them together but keeping them a stable distance apart. Sharing electrons between two or more atoms.

Define cholesterol

a compound of the sterol type found in most body tissues, including the blood and the nerves. Cholesterol and its derivatives are important constituents of cell membranes and precursors of other steroid compounds, but high concentrations in the blood (mainly derived from animal fats in the diet) are thought to promote atherosclerosis.

Define chitin

a fibrous substance consisting of polysaccharides and forming the major constituent in the exoskeleton of arthropods and the cell walls of fungi.

Define double helix

a pair of parallel helices intertwined about a common axis, especially that in the structure of the DNA molecule.

What is a chemical reaction?

a process in which substances are chemically changed into one or more new substances (products). Chemical changes may involve motion of electrons in the forming and breaking of chemical bonds.

What is a chemical bond?

a rearrangement of electrons in two atoms that generates a force, causing the atoms to be bound to each other, forming a molecule

Define amino acid

a simple organic compound containing both a carboxyl (-COOH) and an amino (-NH2)

What is an aqueous solution?

a solution in which water is the dissolving medium or solvent

Define enzyme

a substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction.

Define anabolic steroid

a synthetic steroid hormone that resembles testosterone in promoting the growth of muscle. Such hormones are used medicinally to treat some forms of weight loss and (illegally) by some athletes and others to enhance physical performance

Different isotopes of an element ________________

behave identically in different chemical reactions.

The ______ is the highest level in life's structural hierarchy

biosphere

Define amino group

an NH2 group, consisting of a nitrogen atom attached by single bonds to hydrogen atoms, alkyl groups, aryl groups, or a combination of them; also called amino radical.

What is an organism?

an individual living thing

Define cellulose

an insoluble substance that is the main constituent of plant cell walls and of vegetable fibers such as cotton. It is a polysaccharide consisting of chains of glucose monomers.

Define carboxylic acid

an organic acid containing a carboxyl group. The simplest examples are methanoic (or formic) acid and ethanoic (or acetic) acid.

Define amine

an organic compound derived from ammonia by replacement of one or more hydrogen atoms by organic groups; compound that contains an amino group

Define disaccharide

any of a class of sugars whose molecules contain two monosaccharide residues.

Define carbohydrate

any of a large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and typically can be broken down to release energy in the animal body

Each element consists of one kind of ________?

atom

Define deoxyribonucleic acid

deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information. the fundamental and distinctive characteristics or qualities of someone or something, especially when regarded as unchangeable.

Living things interact with their _______

ecosystem

_________ comes into an ecosystem in the form of sunlight

energy

An educated guess posed as a tentative explanation is called a

hypothesis

What is atomic mass?

is roughly equal to the sum of the individual particle masses of an atom; dependent upon the atom's protons and neutrons and will be different for each individual element.

Researchers testing new drugs usually give the drug to one group of people and give placebos, "sugar pills", to another group. The group receiving the sugar pills

is the control group

At the most fundamental level in life's hierarchy, all living things contain the same basic kinds of

molecules

An ecologist studied the effect of nutrients and predators on the population growth of bacteria on the bottom of a pond. His study of bacteria could not involve which of the following levels in life's structural hierarchy?

organ

Plants carry out _________, producing food for other organisms

photosynthesis

________ make food that supports the ecosystem

producers