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Question 1

Can fats be converted to glucose during starvation? What about glucose converted to fats?

Answer 1

No, humans don’t have the enzymes to do so. Yes, in the liver: glu = converted to FAs, which are converted to triacylglycerides

Question 2

Can bases catalyze peptide bond hydrolysis?

Answer 2

Yep —> can lose enzyme activity

Question 3

PROKS HAVE CIRCULAR DNA AND EUKS HAVE LINEAR Ds DNA

Answer 3

YOU BETTER REMEMBER THIS AND KNOW WHICH ENZYMES ACT ACCORDINGLY

Question 4

Bohr effect

Answer 4

Hemoglobin’s affinity to O2 based on pH and CO2; its affinity to O2 dec when low pH and high CO2

Question 5

GLUT1 vs GLUT2 vs GLUT4

Answer 5

glucose transporter into cell vs glucose transporter into cell; found in liver, intestines, kidneys, beta islet cells of pancreas vs glucose transporter into cell, insulin-regulated, found in adipose tissue and striated muscle (ie. skel and cardiac muscle). All to do glycolysis

Question 6

What does it mean to be a colligative property?

Answer 6

depends on amount of molec, not identity

Question 7

What’s the general idea of Michaelis and Menten? What’s the eqn? What are the 4 asmptns?

Answer 7

find K_M at 1/2Vmax. V = (Vmax*[S])/(Km+[S]) where V=initial vel

COFACTORS ARE NOT PART OF M-M KINETICS

1) this eqn = only used to describe initial rxn vel
2) steady state approximation (ie. [S]»>[P])
3) free ligand approximation (ie. [S]»>[E])
4) rapid equil approximation (ie. Lower Km means higher enzyme-substrate affinity)

Question 8

What are prostaglandins? What can prevent their production?

Answer 8

Unsaturated CAs derived from arachidonic acid that act as autocrine and paracrine signal molecs; they help regulate synthesis of cAMP; also help with inflammation, pain and smooth muscle function. NSAIDS like aspirin

Question 9

x-ray crystallography vs fluorescence in situ hybridization (FISH)

Answer 9

determines proteins’ 3D structure vs molec technique that uses fluorescent probes to bind to DNA to visualize their action)

Question 10

Gs vs Gi vs Gq

Answer 10

Activates adenylate cyclase to inc cAMP vs inhibits adenylate cyclase to dec cAMP vs activates phospholipase C to cleave phospholipid from membrane into PIP2 which then gets cleaved into DAG and IP3, IP3 opens Ca channels in ER which inc Ca in cell

Question 11

Pos inducible operon vs pos repressible operon vs neg inducible operon vs neg repressible operon

Answer 11

activator protein nmlly can’t bind to DNA; inducer molec binds to activator –> activator binds to DNA –> transcpxn vs activator protein always bind to DNA –> constant transcpxn until inducer molec binds to activator protein –> stop transcpxn vs absence of lactose –> repressor binds to operator –> no transcpxn; presence of lactose –> (allo)lactose binds to repressor –> repressor can’t bind to operator –> transcpxn (this described lac operon coding proteins for lactose metab) vs low conc of trp –> repressor can’t bind to operator –> transcpxn; high conc of trp –> trp (as inducer molec) binds to repressor –> repressor binds to DNA –> stops transcpxn (this described trp operon coding proteins for trp biosynthesis)

Question 12

What are operons? Pos vs neg control in gene expression

Answer 12

Inducible or repressible cluster of genes transcribed as single mRNA IN PROKS; no euks!
Presence of activator protein —> turn on gene expression vs gene expression will stay on till a repressor protein turns it off

Question 18

G protein receptors

Answer 18

Have alpha, beta and gamma subunits; when activated, alpha dissociates and binds w/ GTP and activate necessary enzymes (like adenylate cyclase); after doing its function, GTP becomes GDP —> alpha rebinds to beta and gamma subunits. Initiates second messenger cascade like enzyme linked receptors

Question 19

Transition mutation. Are translocations frameshift mutations?

Answer 19

a type of point mutation; changes from purine to purine, pyr to pyr
nope

Question 20

DeltaG for anabolic (monomer to polymer) vs catabolic (polymer to monomer) rxns

Answer 20

> 0, energy-requiring rxns vs < 0, energy-releasing rxns

Question 21

A 3-base system can code how many aa?

Answer 21

64 aa: 4-nitrogen-bases^3-letter-codon

Question 22

DNA wounds around histone via what?

Answer 22

electrostatic interactions

Question 23

Where is glycogen produced and stored? Where is glycogen broken down into glucose?

Answer 23

Produced and stored in liver and skeletal muscle; can also be stored in brain. Only in liver to inc blood sugar b/c skeletal muscle don’t have glucose-6-phosphatase; skeletal muscle uses glycogen for high intensity exercise (epinephrine tells skeletal muscles to do glycogenolysis and glycolysis), brain uses glycogen as cerebral source for emergencies

Question 24

Thiols = more acidic than alcs

Answer 24

Thiols = more acidic than alcs

Question 25

Which cellular environment favors reduced and oxidized form of cysteine?

Answer 25

intracellular environ favors [H] form and extracellular environ favors [O] form

Question 26

What are some ways to turn a tense enzyme (ie. Off) into a relaxed enzyme (ie. On)?

Answer 26

Phosphorylation of enzyme, allosteric regulation (allosteric activator/inhibitor)

Question 27

Native PAGE vs SDS PAGE vs isoelectric focusing vs x-ray crystallography

Answer 27

Analyzes proteins in their native states —> separate by mass to size or mass to charge ratio, you can recover proteins after analysis vs separating proteins based only on mass or size b/c SDS denatures proteins —> gives everything a neg charge, you can’t recover proteins after analysis; SDS = detergent —> amphipathic vs separating proteins based on pI: proteins stop moving when pH = pI (anode is A+ —> anode is acidic and has pos charge) vs detects proteins’ tert structure

Question 28

Most polar basic aa

Answer 28

lysine

Question 29

How to move groups from Haworth projection to chair conformation

Answer 29

Up groups become equatorial and down groups become axial

Question 30

Aldonic acids and alditols

Answer 30

Aldoses can be oxidized to CAs => aldonic acids; aldonic acids have been reducing sugars. Ketones can’t be oxidized to CAs directly but they can tautomerize into aldoses and then get oxidized
Aldoses that have been reduced to alcs

Question 31

Which aa can be phosphorylated?

Answer 31

ser and thr; and his (in proks)

Question 32

Know the structure of triglycerides. Know their purpose and what type of bond and type of rxn bond makes. Know chylomicron

Answer 32

3 fatty acid chains + glycerol (a 3 C alc)
dehydration –> 3 water molec released
ester bond
Purpose: storage lipids
Chylomicron = lipoproteins consisting of triglycerides, phospholipids, proteins and cholesterol

Question 33

Most polar vs least polar of nonpolar aa

Answer 33

proline vs isoleucine b/c long alkyl chain

Question 34

T/F: arginine has resonance

Answer 34

T

Question 35

What factors affect enzyme activity?

Answer 35

High temp (optimal = 37 degrees C/310 K), pH not 7.4 physiologically and affecting ionization, high salinity affecting H bonds and ionic bonds

Question 36

What are restriction enzymes/restriction endonucleases? Type I vs II vs III vs IV restriction enzymes

Answer 36

Enzymes that recognize specific dsDNA seq, particularly palindromic —> once they find the seq, they break the DNA backbone; sometimes they yield sticky ends. These enzymes = found in bacteria and even help protect them from viruses (so they can chop up the infected DNA)
cuts DNA at or near restriction sites which = remote from recognition sites, require ATP and S-adenosyl-L-methionine vs cleaves w/in short distances from recognition sites, requires Mg vs cleaves w/in short distances from recognition sites, requires ATP vs targets modified DNA (like methylated DNA)

Question 37

Beta vs alpha amylase

Answer 37

Cleaves at nonreducing ends (end of acetal) —> yields maltose vs cleaves randomly —> yields maltose and glucose

Question 38

Benedict’s reagent

Answer 38

there’s aldehyde because it’s copper

Question 39

How does ketogenesis occur?

Answer 39

Prolonged starvation, excess acetyl CoA in liver, beta [O] occurs in mito matrix

Question 40

Why is more energy stored as fats than glycogen?

Answer 40

Fats are more reduced and carry more weight —> more energy

Question 41

Which carbons do phosphate vs nitrogenous base bond to in pentose sugar of nucleotide?

Answer 41

C5 of pentose sugar vs C1 of pentose sugar

Question 42

Aminoacyl tRNA synthetase

Answer 42

Transfers aa to respective tRNA, requires ATP

Question 43

RNA pol I vs II vs III in euks

Answer 43

Synthesizes rRNA vs synthesizes mRNA and snRNA vs synthesizes tRNA and some rRNA

Question 44

Gap junctions vs tight junctions vs desmosomes vs hemidesmosomes

Answer 44

aka connexons made up of connexin, direct cell to cell communication by connecting cytoplasms vs prevents solutes from leaking out into space b/w cells via paracellular route vs act as spot welds to attach adjacent cells by anchoring their cytoskeletons vs act as spot welds to attach epithelial cells to underlying structures

Question 45

Types of fac diffusion

Answer 45

carrier proteins (open 1 side except in occluded state - not open on either side), channel proteins (open both sides)

Question 46

pinocytosis vs phagocytosis

Answer 46

endocytosis of fluids AND DISSOLVED PARTICLES vs solids