Human Physiology Test 1 Exam 1 Answers

Which of the following is an important characteristic of lipids?

ANSWER : They are nonpolar.

Choose the correct example of signal amplification.

ANSWER : One hormone molecule causes the activation of more than one second messenger molecule

Which is the most abundant biomolecule in the human body?

ANSWER : Proteins

Which of the following BEST demonstrates solubility?

ANSWER : A teaspoon of salt disappears when stirred into a glass of water.

Hydrophobic solutes are generally soluble/insoluble (choose one) in water, due to the presence of _____ covalent bonds between the atoms in each solute molecule.

ANSWER : insoluble; nonpolar

Water readily dissolves ions because the atoms i water molecules are bonded by _____ bonds.

ANSWER : polar covalent

For ions in solution, the measurement unit that considers the number of electrical charges carried by each ion is the _____.

ANSWER : equivalent

Which compound is hydrophobic?

ANSWER : Butter

What is a substance that can moderate the change in pH of a solution?

ANSWER : A buffer

What would cause a protein response rate to be maximal?

ANSWER : The protein binding sites are saturated.

Which of the following builds new strands of DNA?

ANSWER : DNA plymerase

Which statement best describes strand characteristics as it relates to DNA replication?

ANSWER : The leading strand is built continuously, and the lagging strand is built in pieces.

Which protein joins together the Okazaki fragments of DNA in the lagging strand?

ANSWER : DNA ligase

Which statement about DNA is false?

ANSWER : DNA ligase adds nucleotides to the lagging strand.

Lemon juice has a pH of about 2.0, compared to a pH of about 1.0 for stomach acid. Therefore, the concentration of H+ in stomach juice is _____ than that of lemon juice.

ANSWER : 10 times higher

Proteins that bind signal molecules and initiate cellular responses are called _____.

ANSWER : receptors

A protein that no longer functions because its shape has changed (e.g., as a result of heating) has been _____.

ANSWER : denatured

Stanley Miller set out to demonstrate an explanation for the origins of organic molecules using a combination of simple organic molecules, heat and periodic burst of electricity through the mixture, ultimately producing what kind of molecules?

ANSWER : amino acids

Glycosylated molecules are those formed with which group of organic compounds?

ANSWER : carbohydrates

Cells regulate their level of activity by regulating the amount of proteins present in the cell at any given time, so an up regulation of enzymes would be expected to …

ANSWER : increase the level of productivity of chemical reactions that rely on them.

Which groups of elements make up more than 90% of the body’s mass?

ANSWER : O, C, H

The organic molecules know as phospholipids are key components of cell membranes and composed of 

what monomeric units?

ANSWER : both glycerol and fatty acids.

Which of the following is a way to recognize a carbohydrate by looking at its name only?

ANSWER : It ends in -ose.

Which of the following is NOT considered an essential element for a living organism?

ANSWER : mercury

The larges carbohydrate molecules are called polysaccharides because they are composed of _____ 

molecules bonded together with one another.

ANSWER : sugar

Essential amino acids that are used to build proteins…

ANSWER : can be derived from the foods we eat and digest.

Which of the following are examples of cations?

ANSWER : Ca2+

A positively charged ion is called a(n)

ANSWER : cation.

The most important polar molecule is _____ because it is practically a universal solvent.

ANSWER : water.

A free radical is a …

ANSWER : molecule with an unpaired electron.

The chemical bonding behavior of an atom is directly determined by…

ANSWER : the number and arrangement of electrons.

Atoms in a covalent molecule…

ANSWER : can share electrons in single pairs, double pairs, or triple pairs.

The weak interactions between atoms tat keep atoms near each other but don’t tightly bind them together are called..

ANSWER : hydrogen bonds and van der Waals forces.

All of these statements about carbohydrates are true except one. Identify the exception.

ANSWER : Glycogen is important both for energy storage and to provide structure for cells.

Each amino acid differs from others in the …

ANSWER : chemical structure of the R group.

Nucleic acids are polymers of units called …

ANSWER : nucleotides

A nucleotide consists of …

ANSWER : five-carbon sugar, a nitrogenous base, and a phosphate group.

The most important energy-transferring compound in cells is a nucleotide know as …

ANSWER : adenosine triphosphate

Which bases below are purines? 1. adenine 2. cytosine 3. guanine 4. thymine 5. uracil

ANSWER : 1 and 3 adenine and guanine

Polymers are a typical formation of____ molecules.

ANSWER : organic

Cholesterol is …

ANSWER : a precursor to steroid hormones and structural component of cell membranes.

A molecule referred to as highly soluble is …

ANSWER : very likely to dissolve in water and is called aqueous.

Which of the following is an important characteristic of lipids?

ANSWER : they are nonpolar

Which compound is hydrophobic?

ANSWER : butter

What would cause a protein response rate to be maximal?

ANSWER : The protein binding sites are saturated

Proteins that bind signal molecules and initiate cellular responses are called

ANSWER : receptors

A protein that no longer functions because its shape has changes has been

ANSWER : denatured

Stanley Miller produced what kind of molecules?

ANSWER : amino acids

Glycosylated molecules are those formed with which group of organic compounds?

ANSWER : carbohydrates

Cells regulate their level of activity by regulating the amount of proteins present in the cell at any given 

time, so an up regulation of enzymes would be expected to

ANSWER : increase the level of productivity of chemical reactions that rely on them

Which group of elements makes up more than 90% of the body’s mass?

ANSWER : O, C, H

The organic molecules known as phospholipids are key components of cell membranes and composed of 

what monomeric units?

ANSWER : both glycerol and fatty acids

How to recognize a carbohydrate by looking at its name only

ANSWER : It ends in -ose

The largest carbohydrate molecules are called polysaccharides because they are composed of ____ 

molecules bonded together with one another.

ANSWER : sugar

Essential amino acids that are used to build proteins

ANSWER : can be derived from the foods we eat and digest

The weak interactions between atoms that keep atoms near each other but don’t tightly bind them together are called

ANSWER : hydrogen bonds and van deer Waals forces

All of these statements about carbohydrates are true except one. Identify the exception.

ANSWER : Glycogen is important both for energy storage and to provide structure for cells

In regard to lipids, the term unsaturated refers to

ANSWER : the presence of double bonds between adjacent carbon atoms in a fatty acid

Each amino acid differs from others in the

ANSWER : chemical structure of the R group

Nucleotide consists of a

ANSWER : five-carbon sugar, a nitrogenous base, and a phosphate group

A nucleotide containing cytosine would pair with a nucleotide containing

ANSWER : guanine

The most important energy-transferring compound in cells is a nucleotide known as

ANSWER : adenosine triphosphate

which bases are purines?

ANSWER : adenine and guanine

Polymers are a typical formation of ____ molecules

ANSWER : organic

Cholesterol is

ANSWER : a precursor to steroid hormones and a structural component of cell membranes

Proteins containing more than one peptide chain

ANSWER : quarternary

Protein that is soluble in water

ANSWER : globular

Keratin

ANSWER : fibrous

Interactions between different globular or fibrous polypeptide chains result in which type of structure?

ANSWER : quaternary