Chapter 1-4 Homework

What are the tenets of the Cell theory?

All organisms are composed of one or more cells. The cell is the structural unit of life. Cells can arise only by division from a preexisting cell.

Why are free ionic bonds of little importance and relatively unlikely to form in living organisms?

Cells are composed mostly of water, which interferes with ionic bonds between free ions

What characteristics are the basic properties of cells?

Cells are highly complex and organized. Cells possess a genetic program and the means to use it. Cells are capable of producing more of themselves. Cells acquire and utilize energy.

What major feature distinguishes the theoretical first eukaryotic common ancestor (FECA) from prokaryotes?

Closed internal compartments

What characteristics distinguish prokaryotic and eukaryotic cells?

Eukaryotes have membrane-bound organelles; prokaryotes do not. Prokaryotes have relatively little DNA; eukaryotes generally have much more. Eukaryotic chromosomes are linear; prokaryotic chromosomes are circular. Prokaryotic DNA is naked or nearly naked; eukaryotic DNA is usually heavily associated with protein.

Which interaction is MOST important in enhancing the solubility of macromolecules in water?

H bonds

____________ help(s) unfolded or misfolded proteins achieve their proper three-dimensional conformation.

Molecular chaperones

Which of the following tripeptides would be MOST likely to be soluble in an organic (hydrophobic) solvent like benzene?

N - proline - phenylalanine - leucine - C

The MOST electronegative atoms typically present in biological molecules are ____ and ____

O, N

What factors discovered with electron microscopy distinguished prokaryotic from eukaryotic cells?

Their size and the types of their internal structures or organelles

Animal cells do not have:

chloroplasts

Proteins are often composed of two or more distinct modules that fold up independently of one another. They often represent parts of a protein that function in a semi-independent manner. These modules are called ______

domains

Virtually all chemical changes that take place in cells require _________, molecules that greatly increase the rate at which a chemical reaction occurs.

enzymes

The MOST stable atoms and thus those that are typically nonreactive are the atoms that have _______

full outer shells

Which amino acid is MOST likely to be found in the core of a protein?

methionine

What is the MOST appropriate unit of measurement for MOST types of cells?

micrometers

A student observes an object under the microscope that measures about 3 micrometers. The object is most likely a(n):

prokaryotic cell

What is a nucleotide made of?

sugar, phosphate, nitrogen base

Where are hydrophobic interactions MOST likely to occur?

the core of a water-soluble protein

The primary structure of a polypeptide is:

the specific linear sequence of amino acids that constitutes the polypeptide chain

Phospholipids have:

two fatty acid chains and the glycerol backbone is bonded to a small polar group