Exam 1

What is a polar molecule?

A molecule that is slightly negative (δ–) at one end and slightly positive (δ+) at the other due to unequal sharing of electrons.

What is chemically nonsensical about the structure H-C=C-H?

The structure has too few covalent bonds; each carbon must form four bonds to satisfy the octet rule.

Chloroplasts function by harnessing what to produce energy?

Sunlight (via photosynthesis).

Which is NOT a characteristic of all living organisms?

Being composed of multiple cells; many organisms are unicellular.

What organelles are used to break things down in cells?

Lysosomes; they contain digestive enzymes.

Polymers are broken down into monomers through which type of reaction?

Hydrolysis (addition of water to break a bond).

Correctly describe the nature of a phospholipid's components.

The phosphate head is hydrophilic (polar), and the lipid tail is hydrophobic (nonpolar).

What best describes natural selection?

Unequal reproductive success.

Which statement best distinguishes hypotheses from theories?

Hypotheses are narrow in scope; theories are broad and supported by extensive evidence.

The membrane of a cell is often referred to as the blank of the cell.

The skin of the cell.

True or false: Cilia and flagella are synonymous terms.

False; they differ in length, number, and movement.

True or false: All compounds are molecules but not all molecules are compounds.

True; molecules can be one element (O₂), compounds must include ≥2 elements (H₂O).

The rough endoplasmic reticulum can best be described as:

The site of extensive protein synthesis (due to ribosomes).

If you change the number of the atom becomes a different element.

Protons.

Which term includes all the others (Polysaccharide, Carbohydrate, Monosaccharide, Disaccharide)?

Carbohydrate.

An atom can be changed into an ion by adding or removing .

Electrons.

Monomers are joined to form larger polymers through reactions.

Dehydration (synthesis) reactions.

Which statement about saturated fats is true?

Saturated fats have the maximum number of hydrogens (no double bonds).

Which of the following is part of the cytoskeleton?

Microtubules.

True or false: The flagella of both eukaryotes and prokaryotes are nearly 100% identical.

False; their structures are fundamentally different.

Which is the lowest level in level of organization?

Tissue (Cell → Tissue → Organ).

A shortage of phosphorus would make it especially difficult for a plant to manufacture:

DNA and RNA (phosphate backbone).

In eukaryotic cells, lipids are synthesized within the .

Smooth endoplasmic reticulum (SER).

Which structure includes all the others (RER, Golgi apparatus, SER)?

Endomembrane system.

Which of the following is not a chemical reaction?

Ice melting into liquid water (physical change).

The statement "People who ingest rotavirus will subsequently experience acute diarrhea" is classified as:

A hypothesis (testable prediction).

What would tell you whether an unknown cell is prokaryotic or eukaryotic?

Presence of a nucleus (eukaryotic) or lack thereof (prokaryotic).

Humans and other animals cannot digest wood because they:

Lack cellulase, the enzyme that breaks down cellulose.

The atomic mass number of an atom is determined by the sum of the number of .

Protons + neutrons.

One molecule of dietary fat is made by joining three molecules of to one molecule of .

Fatty acids to glycerol (forming a triglyceride).

Which has a higher concentration of hydrogen (H⁺) ions?

Vinegar, pH 2.8 (most acidic).

True or false: DNA and RNA share two nitrogenous bases.

False; they share three (A, G, C).

An atom is:

The smallest unit of an element.