MCDB MIDTERM 1

Which is a prokaryotic domain?

Archaea

There are _____ naturally occurring elements

94

What are the 4 most abundant elements found in living organisms?

Hydrogen, oxygen, nitrogen and carbon

Which of the following molecules has the shape of a completed tetrahedron?

Methane (CH4)

Which of the following is a trace element?

Copper

Hydrophilic substances, but not hydrophobic substances, _________

Have charges or partial charges to which water molecules can adhere

Adhesion is best described as

The clinging of one substance to another substance

Ionic bonds form as a result of

Attraction between ions that have opposite charges

Coastal climates are more moderate than inland climates primarily because of water’s high

specific heat

How many electrons would be present in the valence shell of a sulfur atom (atomic number 16, mass number 32)

Six electrons

When the number of protons and electrons possessed by an atom are unequal, the atom is an

ion

Which has negligible mass?

electron

Isotopes of an element will always differ in

atomic mass

An atom that normally has _____ in its outer shell would not form chemical bonds with other atoms.

Eight electrons

Sweating has a cooling effect because of water’s high

heat of vaporization

Cells are surrounded by water and they consist of about 70 to 95 percent water. As a result

• Dissolved substances can be easily transported within a cell or between cells in multicellular organisms.

• A variety of nutrient molecules is readily available as dissolved solutes

• The temperature of living things tends to change relatively slowly

• Waste products produced by cell metabolism can be easily removed.

The number of protons in an uncharged atom

equals the number of electrons

When the number of protons and electrons possessed by an atom are unequal, the atom

is an ion

A covalent bond will be polar if

one of the atoms sharing electrons is more electronegative

The tendency of water molecules to stay close to each other as a result of hydrogen bonding

• is called cohesion

• provides the surface tension that allows leaves to float on water

• acts to moderate temperature

• keeps water moving through the vessels in a tree trunk

The chemical characteristics or reactivity of an element depend mostly on the

number of electrons on its outermost shell

You can fill a glass of water to just slightly above the rim without it spilling over. What property of water best explains this phenomenon?

Surface tension

Which of the following functional groups increases the solubility of organic compounds in water

• OPO32

• OH

• NH2

• COOH They all have either oxygen or hydrogen in their compounds

Emergent properties of living systems are defined as properties that

are due to the arrangement and interactions of parts as complexity increases

Which of the hydrocarbons has a double bond in its carbon skeleton?

C2H4

Manufacturers make vegetable oils solid or semisolid at room temperature by

adding hydrogen atoms to the fatty acid hydrocarbon chains

Which of the following components of a tossed salad will pass through the human digestive tract and be digested the least

cellulose (in the lettuce)

Cellulose is a

polymer

Cellulose is made of many

glucose molecules

In what polysaccharide form do plants store glucose to be available later as an energy source?

starch

Amylase is an enzyme that breaks down starch. Why can’t the same enzyme break down cellulose?

The monosaccharide monomers in cellulose are bonded in a different orientation than in starch

The lipids that form the main structural component of cell membranes are

phospholipids

What is the appropriate term for a group of all the individuals that can mate with each other living within a specified area?

Population

Some lipids are formed when fatty acids are linked to glycerol. These subunits are linked together by

ester linkages

Which of the following are properties of hydrocarbons?

• hydrophobic

• nonpolar

• good source of stored energy

The sex hormones estrogen and testosterone belong to which class of molecules?

lipids

Which is an organic molecule?

CH4

Which is a polymer?

Cellulose, a plant cell wall component

The process that accounts for the unity and the diversity of life is

evolution

Eukaryotic organisms that decompose dead organisms and absorb dissolved nutrients from their surroundings would be found in which kingdom?

Fungi

Energy_____ an ecosystem

flows through

Chemical elements______ an ecosystem

cycle within

Which of the following is the fundamental unit of structure and function in living organisms?

cell

All the organisms on your campus make up___

a community

Capillary action involves the following three properties of water: adhesion, _________, surface tension

cohesion

On large scale, the earth is 75% water. What property of water provides the insulation and warmth of the Earth’s surface?

specific heat

The first falling leave of the season has tumbled from the air and landed on top of the pond. It does not sink, but yet float on top of the surface. What is happening on a molecular level that is preventing the leaf from sinking?

There is not enough weight to break the hydrogen bonds between water molecules at the surface of the water.

The organisms depicted above (mushrooms) belong to the following group

eukaryotes

The organism depicted above most likely belongs to

bacteria

Water molecules bond in a crystalline form as the temperature of water drops. This creates more space between water molecules. What characteristic of water does this change describe?

density

What is meant by the fact that water is a “polar” molecule?

It has an uneven distribution of charge, like a tiny magnet with positive and negative ends.

What is the primary source of energy that makes life on earth possible?

the sun

What type of bonds interconnect the molecules by… shown in this image?

hydrogen

Which of the following is a trace element?

zinc

What is the sequence that correctly lists life’s hierarchy of levels of organization from lowest to highest?

molecule, organelle, cell, tissue, organ, organism