Biochemistry

Question 1

Kinetic Energy

Answer 1

energy in motion

Question 2

Potential energy

Answer 2

stored energy

Question 3

Examples of kinetic energy

Answer 3

1. Electrons moving along ETC
2. Myofilament sliding during contraction
3. Blood flowing through vessels

Question 4

Examples of potential energy

Answer 4

1. The H+ gradient that builds in the space btwn the inner and outer membrane of the mitochondria
2. Energy from ATP stored
3. Pressure gradient generated from a systolic contraction of the heart

Question 5

1st Law of Thermodynamics

Answer 5

In a closed system, energy cannot be created or destroyed

Question 6

Apply the 1st Law to Phys

Answer 6

Instead of creating new energy, energy is converted to other forms through chemical reactions

Question 7

2nd and 3rd Law of Thermodynamics

Answer 7

Entropy will increase in a closed system and reach a constant value at absolute zero

Question 8

Apply the 2nd and 3rd Laws to Phys

Answer 8

There is no perfect energy conversion. Some of the energy in ATP drives the Na/K ATPase but some that energy is given off as heat.

People are not closed systems. They eat food and take in oxygen.

Question 9

Hydrogen bonds

Answer 9

weak bond because they are easily and rapidly formed and destroyed under normal physiological conditions).

Hydrogen has attraction between hydrogen and oxygen or nitrogen because of uneven distribution of electrons

Question 10

Ionic bonds

Answer 10

• Electrostatic attractions btwn cations and anions
• Dissociate in water.
• NaCl has an ionic bond that permits it to dissociate in water.
• Body fluids are solutions of ions

Question 11

Covalent bonds

Answer 11

• Bond through shared electrons
• Strongest bonds
• Store the most energy
• Their formation require enzymes to form and/or break
• Metabolism is regulated through the regulation of enzymes

Question 12

Free radical

Answer 12

• Have an unpaired electron in the outer shell
• It is not necessarily charged, but it is reactive
• . It can be formed where there are high levels of oxygen, and it will react with proteins, fats, and DNA.

Question 13

How are free radicals both beneficial and harmful?

Answer 13

• beneficial because they are important biological signaling molecules that protect against disease and play a pivotal role in the benefits of exercise.
• harmful because they will react with proteins and fats, causing DNA mutations and destruction of cell membranes.

Question 14

Polarity

Answer 14

the separation of an electric charge, leading to a molecule or its chemical groups having an electric dipole moment with a negatively charged end and a positively charged end.

Question 15

Examples of polar molecules

Answer 15

water
ethanol
ammonia

Question 16

Examples of non-polar molecules

Answer 16

oxygen, methane, and the noble gases

Question 17

Characteristics of polar molecules

Answer 17

• Polar molecules are highly water soluble and therefore are able to form hydrogen bonds
• The polarity influences its function in the cell because water participates in chemical reactions through hydrolysis and dehydration synthesis

Question 18

pH

Answer 18

measure of hydrogen ion concentration.

It is the negative log of H+ concentration in molars. As H+ ion concentration increases, pH decreases

Question 19

Protonation

Answer 19

the association of H ion with other molecules

Question 20

Rltsp of pH and protonation

Answer 20

Side chains tend to be ionized at physiological pH. If there is a more acidic environment, then protonation of a carboxyl group may occur.

Amino groups tend to be protonated at physiological pH. However, if the pH becomes quite alkaline, then the protonation could be lost.

Question 21

Amino acids

Answer 21

Amino acids have a repeating structure. They have a central carbon, a carboxyl (acid) group, an amino group, a hydrogen, and a remaining group

Question 22

Primary structure

Answer 22

The sequence of amino acids in a polypeptide chain. Determines how a protein will fold.

Question 23

Secondary structure

Answer 23

Secondary structure refers to a local, folded structure that forms within a polypeptide due to interactions between atoms of a backbone.

Question 24

Tertiary structure

Answer 24

Tertiary structure refers to an overall 3-dimensional structure of a polypeptide.

Question 25

Quaternary structure

Answer 25

Quaternary structure of a protein refers to proteins which are made up of multiple, polypeptide chains.

Question 26

Enzymes

Answer 26

globular proteins that function as biological catalysts

very specific. For example, kinases are a group of enzymes that add a phosphate group.

Question 27

How enzymes work

Answer 27

They increase reaction rates by increasing the frequency of collisions, decreasing the activation energy and providing correct orientation

Question 28

Enzymes and cell metabolism

Answer 28

Biological regulation of reactions occurs through regulating enzymes and sometimes through cofactors like Ca2+, Mg2+, and vitamins.

Question 29

Carbohydrates for nutrition purposes

Answer 29

• Hexoses are important energy source
• Glucose is essential for the brain. It is broken down via glycolysis and then further via the Krebs cycle to produce ATP
• Glycogen is a reservoir of available energy stored within bonds of individual glucose monomers. Hydrolysis of glycogen leads to the release of glucose monomers in the blood, preventing blood glucose levels to reach dangerously low levels.

Question 30

Hexoses

Answer 30

glucose, galactose, fructose

Question 31

Carbohydrates for structure

Answer 31

sugars added to lipids make glycolipids and sugars added to proteins make glycoproteins, which helps to generate a more complete structure in the cell membrane.

Question 32

Triglyceride

Answer 32

Three fatty acids covalently bonded to a glycerol backbone.

• High density energy storage molecule
• Hydrophobic

Question 33

Phospholipids

Answer 33

• similar to TGLs
• Have fatty acid tail, but only 2 and the glycerol backbone includes a polar group such as a choline or inositol
• Main component of bilayer
• Amphipathic which is why they form bilayers spontaneously
• major component in surfactant

Question 34

Steroids

Answer 34

4 ring cholesterol derivatives

• These molecules modify the stiffness of lipid bilayers.
• Function as hormones, e.g. estradiol, cortisol, vitamin D etc.

Question 35

Saturated TGLs

Answer 35

All single bonds within their carbon chains (these are easier to convert to cholesterol).

Question 36

Unsaturated TGLs

Answer 36

As double bonds are added, the molecules are unsaturated. Omega three fatty acids have a double bond at the end of the fatty acid chain.

Question 37

How are high energy compounds essential for cell physiology? Give examples

Answer 37

Needed to help the cell function, produce ATP, protection, respiration, and regulation

Examples: ATP, NAD and FADH (H+ carrier), coenzyme A (carrier in the Kreb cycle), and creatine phosphate (substrate phosphorylation).