Week 1 - from Pset Flashcards
True or False: The DNA floats freely in the cytoplasm.
F - in eukaryotic organisms, the dna floats freely within the nucleus, which contains nucleoplasm, not cytoplasm. The nucleus is separated from the cell’s cytoplasm
True or False: The central dogma of molecular biology holds that RNA is transcribed into DNA which is then translated into proteins.
F - quite the contrary. The central dogma stats that DNA is transcribed to RNA which is then translated into Amino Acid chains (polypeptide chains), also known as “proteins”. Reverse transcription via reverse transcriptase is present in retroviruses, and some non-retro viruses, and in certain retrotransposons, as well as telomeres, but not in most of our DNA or cells.
True or False: Enhancers bind to DNA at specific sequences to upregulate the expression of genes.
Enhancers are regions/sequences of DNA that attract and are bound to by activators, which then upregulate the expression of genes
What do enhancers do?
regions/sequences of DNA that attract and are bound to by activators, which upregulate the expression of genes
Are enhancers always in close proximity to the genes that they affect?
No, enhancers can be very far away, and still serve to activate certain genes as the cromatin folds upon itself
How do you determine valence electrons?
Counting the number of electrons in a valence (outer) shell.
what is a polypeptide bond?
A peptide bond is a chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water (H2O).
is a peptide bond covalent?
yes!
The phosphoanhydride bonds between three phosphates in ATP are what types of bonds?
covalent
The glycosidic bond between glucose and galactose in lactose is what type of bond?
covalent
amphipathic
structure/molecule with both hydrophobic and hydrophilic properties
polar amino acids are ______
hydrophilic
nonpolar amino acids are______
hydrophobic
A phospholipid molecule consists of a ______ head and two _______ fatty acid tails. Because of their composition, phospholipids are considered _______ and will spontaneously form bilayers or micelles in water.
polar, non-polar, amphipathic
phospholipid _______
bilayer
3 parts of hydrophilic head of phospholipid molecule
polar group(choline), phosphate, glycerol
ATP stands for
adenoshine triphosphate
what is the basis for a van der Waals attraction
form of electrical attraction caused by fluctuating electric charges whenever two atoms are a vier short distance apart
3 functions of the plasma membrane (phospholipid bilayer)
receiving information (communication), import and export of molecules, cell growth and motility
most common phospholipid in most molecules
phosphatidylcholine
proteins account for ___ of the mass of most plasma membranes
50%
are transmembrane proteins hydrophobic?
they’re amphipathic
a polypeptide chain will usually cross the bilayer as what secondary structure?
Alpha helix
T/F - Energy from ATP is required to repair membrane tears.
False - membrane is self repairing/sealing
T/F? - The fluidity of a membrane does not depend on temperature, but it does depend on the structure of the hydrocarbon tails.
False - depends on temp and structure
T/F ? - Bilayers that contain a large proportion of unsaturated hydrocarbon tails are more fluid than those with lower proportions.
False - the opposite is true. cholesterol adds rigidity and structure
T/F? - Phospholipids are more likely to move laterally within their monolayer than to flip to the other side of the bilayer.
T - they’re highly unlikely to flip, and are much more likely to re-arrange
T/F? - The cell membrane allows for the internal and external cellular environments to accumulate different charges.
True
3 Stages of cellular metabolism
1: Breakdown of large macromolecules to simple subunits. 2: Breakdown of simple subunits to Acetyl CoA, plus production of small amounts of ATP and NADH 3: Complete oxidation of acetyl CoA to H2o and Co2, making large amounts of ATP in mitochondria
What does ADP stand for?
Adenosine diphosphate
ATP ____ energy in _____ to become ADP
loses , hydrolysis
ADP goes through a ______________ reaction to become ATP
phosphorylation
Because ATP loses energy while becoming ADP, it is energetically ________________
favorable
ATP hydrolysis is _______ with non-favorable reactions
coupled
Any reaction that involves the xfer of a phosphate group to a molecule is called a _______ reaction
phosphorylation
phosphorylation is a ________ reaction
condensation
Pi
inorganic phosphate
ATP hydrolysis yields between ___ and ___kcal/mole of usable energy
11 and 13
ADP + Pi =
ATP
ADP + Pi to ATP is energetically_________
unfavorable
ADP to ATP is a _______ reaction
condensation
by itself, is ATP hydrolysis fast or slow
slow, it needs a catalyst to overcome the activation barrier
T/F - our cells generate and store large amounts of ATP
False - it is continuously regenerated
the opposite of a condensation reaction
hydrolysis
heat is energy in its most ________ form
disordered
oxidation
addition of oxygen atoms, removal of electrons
reduction
addition of electons
T/F - The products of ATP hydrolysis are more stable than the reactants because they possess a more positive Gibbs free energy
False, the delta G is negative in this reaction, as the conversion of ATP to ADP + Pi is favorable
equation for delta G
G products - G reactants = delta G
3 ways that an enzyme serves as a catalyst
- binding with two molecules and encouraging a reaction.
- Changing positive/negative charges which results in a reaction.
- bending or contorting a molecule into a state / structure that favors a reaction
An active site in an enzyme includes the _________ and the __________
binding site and catalytic site
an enzyme bonds with a ________
substrate
allosteric regulation
regulation of protein by the binding of an “effector” to the allosteric site, which is NOT the active site
T/F The binding of the regulatory ligand always decreases the catalytic activity of the enzyme.
False - this isn’t always the case. The regulatory ligand my increase or decrease the catalytic activity, operating as either activators or inhibitors.
T/F - The regulatory ligand binds directly to the active site.
F - the regulatory ligands will bind to the allosteric, or regulatory site.
where does glycolysis take place?
the cell cytoplasm
which comes first, glycolysis or the citric acid cycle?
glycolysis
where does the citric acid cycle take place?
in mitochondria
where is acetyl coa produced?
in mitochondria
what is used to produce acetyl coa?
pyruvate
put these in the correct order: citric acid cycle, pyruvate–> acetyl coa , glycolysis
glycolysis, pyruvate–>acetyl coa, citric acid cycle
where does fermentation take place?
the cell’s cytoplasm
T/F - Many citric acid cycle intermediates are also crucial in producing amino acids, lipids, and nucleotides.
True - it provides the building blocks for many important molecules
T/F - The CO2 made from the CAC comes directly from O2.
F - the Co2 will occur in anaerobic conditions, as the CAC turns carbon atoms of the acetyl groups into Co2
T/F - The common entry point for both sugars and fatty acids is acetyl CoA.
True
What are the products of the CAC?
ATP (GTP), Co2,NADH,FADH2
Does the CAC result in Pyruvate?
no
