BIOCHEMISTRY

Question 1

Describe the different types of bonds

Answer 1

1. Dipole-dipole: attraction between polar molecules due to opposite partial charges.
2. Ionic bond: In ionic bonding, one atom donates electrons to the other. (cation + anion) (metal + non-metal)
3. Covalent bond: Sharing of electron pairs between two atoms to form molecules (non-metal + non-metal)
4. Hydrogen bond: Strong attraction between a hydrogen atoms and a highly electronegative atom in another molecule.

Question 2

What are the four major biochemical reactions and describe each reaction.

Answer 2

1. Hydrolysis: Water is used to break down a larger molecule into smaller units
2. Condensation: Smaller molecules are joined together to make a larger molecule, with water as a product. (dehydration synthesis)
3. Redox (Oxidation Reduction): Electrons are lost by one atom and gained by another
4. Neutralization: An acid and a base react together to form water and a salt
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Question 3

What are the monomers that makes up the macromolecules (1) carbohydrates, (2) proteins, (3) lipids and (4) nucleic acids

Answer 3

1. monosaccharides
2. amino acids
3. glycerol and three fatty acids
4. nucleotides

Question 4

What features affects the solubility of all functional groups?

Answer 4

Polarity

Question 5

If given an element in the periodic table specify if it will lose or gain electrons to reach stable configuration.

Answer 5

(Practice)

Question 6

Describe each functional group (Carbonyl, Amino, Hydroxyl, Phosphate, Carboxyl)

Answer 6

1. Carbonyl: O double bonded to C
2. Amino: N and Two H
3. Hydroxyl: -OH
4. Phosphate: Very complicated but the main takeaway is that it contains a P and two OH
5. Carboxyl: O double bonded to C and OH
6. Sulfhydryl: S-H (main takeaway is the S from the name)

Question 7

What type of biomolecule is an enzyme?

Answer 7

Protein

Question 8

What is anabolic and catabolic?

Answer 8

anabolic: joining smaller molecules to larger one.
catabolic: breaking dow large molecule into smaller molecules.

Question 9

How do we test for biological molecules in food?

Answer 9

Carbs:

1. Benedict’s reagent (for simple sugas): light blue reagent hat turns color depending on how much sugar there is.
2. Lugol’s Solution (for polysacharides): light brown to deep purple-black if present.

Lipid:
3. Sudan IV (lipid testing): Pink to Red.

Protein:
4. Biuret (protein testing): changes from light blue to deep purple.

Question 10

Describe Passive transport

Answer 10

Passive transport can be described as materials moving from a region high concentration to a region of low concentration. No energy is required. Selective permeability. Essential for essential cellular functions. (diffusion is a type of passive transport) (moves with the concentration gradient)

Question 11

Describe Active Transport

Answer 11

ATP is required for this type of movement from an area of a lower concentration to an area of high concentration. It is facilitated by integral membrane proteins embedded in the cell membrane. (Moves against concentration gradient)

Question 12

Hypertonic, Hypotonic and Isotonic

Answer 12

Hypertonic: putting a cell in a more salty solution. (the cell has more water than salt in this situation) and the water will move out of the cell. Shrinks the cell (plasmolysis).

Hypotonic: putting a cell in a less salty solution. (more NaCL and less water in cell) so the water will move into the cell. The cell will swell and even burst (cytolysis).

Isotonic: the cell and solution are able the same amount of saltiness and water. chemical equilibrium, the solvent going in and out will equal to no net movement. Concentration of solutes (salt) inside and outside is balanced.

Question 13

Enzymes

Answer 13

Enzymes lower the activation energy need for reactants to form products. Once an enzyme is bound to an active site, the reactants form an enzyme-substrate complex. Enzymes have an active site onto which smaller subunits can bind. Enzymes are very pH-sensitive, each enzyme has an optimal pH at which it functions most efficiently. Changes in pH can affect the ability to bind to substrates and can even denature enzymes.

Question 14

Muscle cells require more cellular energy (ATP) to carry out their role of muscle contraction

Answer 14

(T or F)

Question 15

How does an enzyme “lower the activation energy” of a reaction?

Answer 15

-For a reaction to occur, the reactions must overcome the activation energy (Ea) barrier.
-The activation energy is the amount of energy that must be available in order for a reaction to occur.
-Enzymes work by lowering the activation energy (so basically they make it so that reactions won’t need as much energy in order to happen)
-So to summarize, with the enzyme, the path the reactants take to become products is much shorter and faster.

Structure and function
-The structure of enzymes allow them to lower the activation energy of reactions and increase the speed of chemical reaction.
-This is because enzymes attach to the reactants and position themselves for optimal orientation to break or make chemical bonds between them.

Active site and Substrate
-The reactants attach to special sites on the enzyme called “active sites”
-When reactants begin to interact with enzymes, they are called substrates.
-Each substrate binds to the active site that is shaped exactly to fit that particular substrate. (enzyme-substrate complex)

Attachment and Release
-Once the substrate begins to attach, the active site changes shape slightly to perfectly hold the substrate.
-The change in shape (conformation) is called induced fit.
-Finally the substrate is bound and optimally positioned by induced fit the reaction can proceed to form or break chemical bonds.

-Enzymes can also change the chemical environment around a molecule to encourage a reaction
-Enzymes may work with coenzymes for extra help.

-Finally, the enzyme is released unchanged, ready to react again with a new substrate molecule.

Question 16

Allosteric Site

Answer 16

This site in the enzyme will not bind substrates that bind to the active site.
This site is a place on an enzyme that will bind to other specific molecules that will change the shape of the enzyme and influence its ability to be active or not.
This site is involved in turning the enzyme on and off.

Question 17

Compare and describe Enzyme competitive vs non-competitive inhibition

Answer 17

Competitive:
If an enzyme activation or inhibition happens on an active site, it is competitive. Once the inhibitor has attached to the active site, the enzyme is unable to catalyze any reactions at that site. Many poisons act as competitive inhibitors.

Levels of Competition:
-If an enzyme has more than one active site the competitive inhibition can act to slow down the rate of reaction of the enzyme by blocking some active sites, but leaving other active sites open to hold substrate.
-The enzyme becomes completely initiative only if all of the active sites are blocked by inhibitors.

Non-Competitive: (Also called Allosteric)
If the enzyme activation or inhibition happens as a result of changes on the allosteric site, it is classified as non-competitive. The allosteric inhibitor is a molecule that will bind to the allosteric site and force a change in the enzyme making it unable for substrates to bind to the active site.

-Allosteric activation (ON): Activation of enzyme activity occurs when allosteric activators change the enzyme’s shape and stabilize it. - Activation
-Allosteric inhibitors (OFF): Inhibition of enzyme activity occurs when allosteric inhibitors bind to the allosteric site and change the enzyme’s shape and stabilize it to make all of the active sites unavailable to substrates.