Biology Class 1 Flashcards
What are the 4 relevant macromolecules?
Proteins
Lipids
Carbohydrates
Nucleic Acids
How are macromolecules formed?
Through dehydration synthesis/condensation (join two monomers and get water removed)
What are protein monomers?
Amino acids (20)
What bond do 2 amino acids form?
Peptide bond
Which direction does protein synthesis occur in?
N-C synthesis because amino acid is added on the C terminus
What are the different protein structures?
Primary - a.a.
Secondary - alpha helix & beta pleated sheets (h-bonding between the backbone)
Tertiary - folding with side chain interactions WITHIN the polypeptide
Quaternary - Folding with side chain interactions BETWEEN different polypeptides
What are carbohydrate monomers?
Monosaccharides
3 Common Monosaccharides
Glucose
Fructose
Galactose
3 Common Disaccharides
Maltose
Sucrose
Lactose
What is the chemical formula of monosaccharides
C6H12O6
3 Common Polysaccharides
Starch
Cellulose
Glycogen
Difference between functions of carbohydrates and lipids
Short term energy storage vs long term storage
What is the monomer structure of lipids?
Hydrocarbons
What is a saturated fatty acid?
Maximimum number of hydrogens are attached
What is a triglyceride formed with?
Glycerol molecule + 3 fatty acids
Forms ester bond through esterfication
What is a phospholipid composed of?
Glycerol + phosphate + 2 fatty acids
If a molecule has a polar & non-polar end, what is it called?
Amphipathic
What is the function of phospholipid?
Formation of lipid bilayer thus, formation of lipid membrane
What is a terpene composed of?
At least 2 isoprene units
What is the function of terpenes?
Cholesterol
Formation of ear wax
What is a terpenoid?
Modified version of terpene; vitamin A
What are the functions of cholesterol & its derivatives?
Bile salts (to help with fat digestion)
Steroids
Cell membrame
What is cholesterol composed of?
3 six -carbon rings + 1 five-carbon ring
Thermodynamic Formula
ΔG = ΔH - TΔS ΔH = PE TΔS = KE
Definitions of ΔG
ΔG = 0 means it’s in equilibrium
ΔG > 0 means it’s nonspontaneous, endergonic
ΔG <0 means it’s spontaneous, exergonic
What is the energy of activation?
Amount of energy needed to produce transition state
How can you make a reaction faster?
Add a catalyst which will decrease the energy of activation without changing ΔG & will stabilize the transition state
What are 3 characteristics of enzymes as physiological catalysts?
- Not used in reaction
- Must increase reaction rate
- Very specific in what they catalyse
What is the first law of thermodynamics?
Energy is constant
What is the second law of thermodynamics?
Entropy tends to increase
- ΔS= entropy decreases
+ ΔS=entropy increases
Exergonic vs Endergonic
Exergonic (-) - energy is exiting system
Endergonic (+) - energy is added to system
Endothermic vs Exothermic
Endothermic (+ΔH) - inputting heat
Exothermic (-ΔH) - liberating heat
What are two ways enzymes can be turned on or off?
- Phosphorylation
- Allosteric Activator - turns on
Allosteric Inhibitor - turns off
What does Vmax depend on?
- Type of enzyme
2. [E]
What is Km
[S] required for 1/2 of Vmax
As affinity for [E] and [S] increases = Km decreases
Competitive Inhibition
Binds at the active site
Vmax will stay the same
Km will increase
Noncompetitive Inhibition
Binds at the allosteric site
Vmas will decrease
Km will stay the same
Uncompetitive Inhibition
Binds at ES complex
Vmax will decrease
Km will decrease
Mixed Inhibition
Binds at allosteric site
Vmax will decrease
Km will decrease (if binded to ES complex) or increase (if binded to enzyme alone)
9 essential amino acids that cannot be synthesized by adult humans & must be obtained from diet
Lysine Histidine Threonine Valine Leucine Isoleucine Phenylalanine Tryptophan Methionine
Purpose of reaction coupling
- Allows for generation of products that would not normally be formed spontaneously
- Reaction coupling allows for a spontaneous process to drive a nonspontaneous process to make the overall reaction spontaneous
- As this is affecting a thermodynamic property, it is unlikely to have an impact on kinetics (reaction rates would not increase, but would be limited by the slow reaction)
What is a direct enzymatic regulation?
- Protein hydrolysis, phosphorylation/dephosphorylation, allosteric activity (even downstream) NOT modification of transcription factors
What happens when a molecule covalently links to an enzyme site?
This would be known as an irreversible inhibitor; negligible enzyme activity
How is dietary fat broken down?
Dietary fat is broken into 2 fatty acids and 1 monoglyceride prior to absorption. Due to the activity of lipase, triglycerides are broken down into two fatty acids and a monoglyceride before absorption and ultimate reassembly into a triglyceride in the enterocyte.
Which linkage can be cleaved by human amylase?
B(1-6) (starch).
B(1-4) cannot & will pass undigested (cellulose)
