Ch. 3

This is a characteristic of double-stranded DNA:

2 nanometers in width, 10 base pairs per turn, and 0.34 nanometers per base pair

After 3 hours of exercise what are the main sources of energy?

blood glucose and plasma free fatty acids

The molecule the contains the least amount of energy is .

blood glucose.

An athlete asks you tells that even though he loses so much water when exercising, he still manages to gain muscles. His perception is that muscles are made up of mostly water. You explain that

his body must make bonds through a condensation reaction creating muscles and producing water

In the secondary structure of a protein, what bonds, other than peptide bonds, are formed?

hydrogen bonds

Where are most plasma free fatty acids obtained from?

hydrolysis of stored fat

The plasma membrane is made up of a phospholipid bilayer, with the _____________ of the phospholipids_____________.

hydrophilic heads; sticking out toward the interior and exterior of the cell

When forming a semi-solid gel such as gelatin, which molecules does the process of protein coagulation entrap?

water molecules

Olive oil and butter both contain fats; however, one is liquid at room temperature and the other is solid. Why?

The low melting point of unsaturated fats is due to double bonds forming structures that stop tightly bound formations

Unsaturated fats are found primarily in animals and animal products

False

The bond between a carbon and hydrogen atom is a polar bond

false

A mutation is an inheritable change in the DNA of a cell. Mutations are rare occurrences and are often caught by the cell's "proofreading" system during cell replication and so are not passed on to offspring. Why is it more likely for an A nucleotide to mutate to a G nucleotide than to a T nucleotide?

Because A and G are both purines, so the width between the base pairs across the double helix will not be distorted

Trans fats are synthetic saturated fats

False

The most accurate statement about the DNA double helix is

Complimentary base pairing across the double helix allows information to be transferred via RNA transcription and DNA replication

A protein that has many hydrophobic R-groups pointing to the outside of the protein would be found where?

Embedded within a membrane

Saturated fats have one or more double bonds along the carbon backbone

False

The most stable of the following DNA molecules is

GCGTGCAC CGCACGTG

The molecule that stores the MOST energy is

Muscle triglycerides

A carbon atom can form up to four covalent bonds

True

Asymmetrical spacing of the backbones of the DNA double helix generates major and minor grooves.

True

Saturated fats are solid at room temperature

True

Saturated fats have a higher melting point than unsaturated fats

True

Trans fats have a higher melting point than natural unsaturated fats and a lower melting point than natural saturated fats

True

Unsaturated fats have kinks in the hydrogen-carbon chain and therefore the molecules do not lay flat

True

Functional groups help define the properties of macromolecules. The _____ functional group(s) is/are found within amino acids, while carbohydrates contain the _____ functional

amino and carboxyl; hydroxyl

When proteins are denatured, which type of bond is not disturbed?

covalent bonds

A carbon atom has six electrons in its outermost shell

false

Bonds between carbon and other atoms are relatively unstable and readily dissociate, resulting in the formation of new molecules

false

Carbon is a relatively large atom allowing it to bind to more atoms than smaller atoms would, thereby making it more versatile

false

In the stable form of protein, what is generally oriented to the interior of the protein molecule?

hydrophobic portions

What happens to the amount of muscle glycogen used for energy as exercise continues?

it decreases

A gram of fat stores _____ energy than a gram of starch due to ______ within fat molecules relative to starch molecules.

more; a higher proportion of C-H bonds

A person who sprints for 45 seconds obtains most of their energy from

muscle glycogen

What type of bonds link individual amino acids together?

peptide bonds

The correct structure of DNA nucleotides can be presented as

phosphate-sugar-base.

The carbon backbone of a molecule is made up of a string of carbon atoms held together with either single or double bonds

true

DNA _______. RNA, on the other hand, ________.

provides the instructions for the specific sequence of amino acids used to build a protein; functions to convert a nucleotide sequence into an amino acid sequence

When an egg is fried, what happens to the protein in the egg?

the protein is denatured

What happens to the amount of plasma free fatty acids used for energy as exercise continues?

they increase

Oxygen and nitrogen have a stronger electronegativity than carbon (e.g., a strong pull on a shared electron

true

The carbon backbone of a molecule comes in a variety of shapes: linear, ring-like, or highly branched.

true