Biology Exam 1
what factors make up the scientific method?
observations
hypothesis
experiment
analysis data
conclusion/re-test if hypothesis failed
What is the difference between anabolism and catabolism?
What does NOT occur during the M phase of the cell cycle?
Replication of the DNA
What is a state function/property?
Property that does not depend in any way on the system’s past or future.
Example: Energy
**Concept Check**
This type of electrolyte completely dissociates in water and produces a strong conductive solution. Examples include compounds like NaCl and HCl.
What is a strong electrolyte?
Which is the central dogma of biology?
DNA -> (transcription) RNA -> (translation) Protein
What are the 3 types of tonicity? Describe each of their impacts on a cell.
Isotonic: water gain/ lose is equal the solute concentration is the same as inside the cell
Hypertonic: loses water the solute concentration is greater than the inside of the cell
Hypotonic: gains water the solute concentration is less than the inside of the cell
Following DNA replication, each eukaryotic chromosome consists of two identical DNA molecules known as __________
sister chromatids
What is the difference between Exothermic and Endothermic Reactions?
Exothermic reactions: Energy flows out of the system
Example: Combustion reactions
Endothermic reactions: Absorption of energy from the surroundings
Example: Formation reactions
**Precipitation**
The insoluble solid that forms when MgCl2(aq) is mixed with Na2CO3(aq).
What is Magnesium Carbonate. (MgCO3)
__________ refers to all the chemical reactions that occur in the body
Metabolism
What 2 organelles are thought to have arisen from an endosymbiotic relationship with a prokaryote?
Mitochondria and Chloroplast
If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following statements describes the genetic or chromosomal contents of this cell?
A. It is genetically identical to another cell from the same meiosis
B. It has twice the number of chromosomes
C. It has half the chromosomes but twice the DNA of the originating cell
D. It has half the amount of DNA of the cell that began meiosis
D. It has half the amount of DNA of the cell that began meiosis
How much heat is released when 1 gram of iron is reacted with excess Oxygen?
4Fe(s) + 3O2(g) --> 2Fe2O3(s) Change in Heat=-1652 kJ
A) 34.32 kJ
B) 400.74 kJ
C) 7.39 kJ
D) 1652 kJ
C) 7.39 kJ
**REDOX**
The oxidation state of manganese in KMnO4
What is +7
WHAT IS KNOWN: (K= +1; O: -2 x 4 = -8)
WHAT IS ASKED: the value of Mn
WHAT CAN BE DERIVED: (((+1) ± (Mn) ± (-8)) = 0) --> ((-7) ± Mn = 0)) --> Mn must equal positive 7.
Which of the following correctly describes the forms by which energy flows through an ecosystem from entry to exit
Light --> Chemical --> Heat
What are the six major functions of membrane proteins? Briefly describe each
Transport: movement of substances in and out of cells (some involve energy; some don’t)
Enzymatic activity: can be series of multiple enzymatic activity
Signal transduction: cells pick up signals fro function and cause a chain reaction
Cell-Cell recognition: used for tissue and immune system
Intercellular joining: cells way of connecting
Attachment to the cytoskeleton and extracellular matrix (ECM): (self explanatory)
List and explain 3 processes or what phase it occurs in, that occur in meiosis but not in mitosis.
1. Synapsis & Crossing over: When homologous split DNA through specific proteins to create variation within the offspring. (During Prophase I)
2. Joining of Homologous Pairs: When the homologous meet in the middle of the metaphase plate and join together. (During Metaphase I)
3. Separation of Homologous Pairs: Homologous pairs begin to separate by being pulled to the poles. (During Anaphase I)
What is Hess's Law?
The total enthalpy change for a reaction is the sum of all changes.
**Molarity**
The molarity of a solution prepared by dissolving 2.40g of NaOH (mm = 40.00g/mol) in 250 mL of solution.
What is 0.240 M NaOH
Calculation: (mass / molecular mass) = mol; (mol / amount of solution in Liters) = Molarity. --> (2.40g/40.00 g/mol) = 0.0600 mol; (0.0600 mol / 0.250 L) = 0.240M
Name 9 structures of an eukaryotic cell and their basic functions
Cytoplasm: gel-like fluid that fills a cell
Plasma Membrane: phospholipid bilayer that regulates the movement of substances in and out of the cell
Nucleus: membrane-bound structure housing the cell's DNA organized into chromosomes
Mitochondria: energy production through cellular respiration
Smooth ER: involved in lipid synthesis and detoxification processes within the cell
Rough ER: network of membranes involved in protein synthesis and transport
Ribosomes: responsible for protein synthesis
Golgi Apparatus: Modifies, packages, and sorts proteins for secretion
Lysosomes: containing enzymes for intracellular digestion
What are the two stages of photosynthesis? Explain both.
Light Reaction (occurs in thylakoid)
Photosystem 1: functions second; absorbs 700mm wavelength best (P700);
Photosystem 2: functions first; absorbs 680mm wavelength best (P680);
Calvin Cycle (occurs in stroma)
Phase 1 Carbon fixation (ribulose biphosphate → 3-phosphoglycerate)
Phase 2 Reduction ( phosphorylation of 3-phosphoglycerate to G3P {6 ATP+6 NADPH → 6 G3P})
Phase 3 Carbon Regeneration (regenerates initial CO2 receptor {RuBP})
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of the crosses BbTt x BBtt will be expected to have black fur and long tails?
1/2
-Would possibly produce the following:
Bbtt or BbTt or BBTt or BBtt
-Bbtt=black fur and long tails.
What is the standard enthalpy of formation of O2(g)?
0 just like any element in the form in which it exists under conditions of 1atm and 25 degrees Celsius. Other examples-->Na(s), Hg(l), F2(g)
**ACID-BASE REACTION**
The concentration of excess H+ or OH- remaining after this reaction occurs:
25.0 mL of 0.200 M HCL ⇌ 35.0mL of 0.150 M NaOH
What is 0.00417 M OH-
Solution: ** mL need to be converted to Liters**
Step 1: Find Moles of HCl to Determine which compound is limiting.
0.200 M HCl x 0.0250 L HCl = 0.00500 mol H+ (remember comparing H+ and OH- concentration)
Step 2: Find Moles of NaOH to Determine which compound is limiting.
0.150 M NaOH x 0.0350 L NaOH = 0.00525 mol OH-
Step 3: Determine excess now that we know H+ is limiting.
((0.00525 OH-) - (0.00500 H+) = 0.00025 mol OH-
**NOTE: think conceptually if we know the mols of OH- (aka the excess) and the total volume of the solution, then we can find molarity using (Mols/Volume)
Step 4: Find Total Volume
25.0 mL+ 35.0 mL = 60 mL ≈ 0.0600 L
Step 5: Find Molarity Using (Mols/Volume) Formula.
((0.00025 mol OH-) / (0.0600 L) = 0.00417 M OH-