Cells: basic units of life
Where are ribosomal subunits found?
They float freely in the cytosol or attach to mRNA when translation starts, joining together to form a complete ribosome.
What is the equation for pH?
pH = -log[H+]
What is the difference between a covalent bond and ionic bond?
Covalent: sharing of electrons
Ionic: transfer of electrons from one atom to another
Where are non polar proteins found?
What is positive delta G?
Non spontaneous
What is the structure and function of the nuclear envelope?
-To protect and separate the cell’s genetic material from the cytoplasm while regulating what enters and leaves the nucleus.
-Consisting of an inner and an outer membrane, is continuous with the membrane of the rough endoplasmic reticulum
Avogadro’s number was established as the total number of units (atoms or molecules) in a mole, and a mole of any substance is X grams of it, where X is equal to the substance’s molecular weight. A standard unit, the mole, allows scientists to calculate concentrations of
materials dissolved in solutions.
Example: Sulfur has a molecular weight of 32. Therefore, 32 g of sulfur = 1 mole of sulfur = 6 ×
10^23 sulfur atoms.
How many moles and atoms, respectively, are there in 120 grams of sulfur?
a. 3.75; 6 × 10^23
b. 32; 6 × 10^23
c. 1.75; 1.05 × 10^24
d. 3.75; 2.25 × 10^24
D
Which type of bond increases during reduction of an organic molecule, and which type increases during oxidation?
Reduction → C–H bonds
Oxidation → C–O bonds
What determines a proteins function and solubility?
The R group on the amino acids.
What does it mean for a reaction to be energetically favorable?
Spontaneous
What are the three tenets of cell theory?
1. All living organisms are composed of one or more cells
2. The cell is the most basic unit of life
3. All cells arise only from pre-existing cells
The pH of one acid solution is 1 and the pH of lemon juice is 4. How much more basic or acidic
is the acid solution than orange juice? (x-fold)
1000 fold
Fat droplets in the cytoplasm serve as lipid storage in many cells. Which lipid is most commonly stored in these droplets?
triaglycerol
What are disulfide bonds?
Disulfide bonds are covalent links between the sulfur atoms of two cysteine residues that help stabilize a protein’s structure, and they stabilize but do not change a protein’s final conformation.
What is the second law of thermodynamics? What increases when we drop NaCl into a glass of water?
states that the disorder in any system is always increasing.
-entropy is increasing
What are endosymbionts? And what are the two examples?
-endosymbionts are thought to have originated from free-living prokaryotes (bacteria) that were engulfed by ancestral eukaryotic cells and formed a symbiotic relationship inside them.
-However, they still depend on the cell for many proteins and molecules, so they cannot survive on their own for long.
-EX: Mitochondria and Chloroplast
You are asked to prepare a concentrated KOH stock solution in the lab. The molecular mass of KOH is 56 g/mol. How many grams of solid KOH will you need to weigh to make 250 mL of a solution with a concentration of 8 M?
You would need 112 g of KOH.
-moles = M x W = 8 mol/L x 0.25L = 2 mol
-grams = 2 mol x 56 g/mol = 112g
Which of the following statements best describes proteins that can undergo allosteric regulation?
A) Only enzymes are capable of being regulated allosterically.
B) All proteins, including structural proteins, are regulated allosterically.
C) Only membrane-bound receptors are subject to allosteric regulation.
D) Only transport proteins are capable of allosteric regulation.
A
Enzymes are considered the primary proteins subject to allosteric regulation because allosteric molecules bind to sites other than the active site to change the enzyme’s shape and activity.
What kind of interactions stabilize tertiary protein/structures? What is the exception?
Many different non covalent bonds between each subunit.
Disulfide bridges (–S–S–) form covalent links between cysteine residues.
A⇌B
can be expressed in terms of the concentrations of the reactant and product molecules. Which of the following correctly represents this relationship?
A) K = [A]/[B]
B) K = [A] × [B]
C) K = [B]/[A]
D) K = [B] – [A]
C
What are the 4 model organisms?
What are some reasons they are considered MODEL?
Flies (Drosophila), worms (C. elegans), fish (zebrafish), and mice
- short generation times
- easy and inexpensive to maintain in labs
- have well-mapped genomes
- share many conserved genes and biological pathways with humans
(making them ideal for studying fundamental biological processes and human diseases)
What is the pH of a 0.25 M solution of NaOH?
14 - pOH = pH
14 - (-log(0.25))
14 - 0.60 = 13.40
What is allosteric activation?
What is a "protein domain"?
A protein domain is a distinct part of a protein that can fold into a stable three-dimensional structure on its own and often carries out a specific function (such as binding DNA, interacting with other proteins, or catalyzing a reaction).
The standard free energy change (ΔG°) determines whether a chemical reaction will occur spontaneously under standard conditions. Based on the ΔG° values shown below, which reaction is the most energetically favorable?
A) ATP → ADP + Pi ΔG° = −7.3 kcal/mole
B) Pyruvate → Lactate ΔG° = −6.0 kcal/mole
C) Glutamate + NH₃ → Glutamine ΔG° = +3.4 kcal/mole
D) Palmitate (C16 fatty acid) → CO₂ + H₂O ΔG° = −2,340 kcal/mole
D
the largest energy released