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