IB Biology: Seniors
Study Guide Test 2
Kerry Zimmerman
Chapter 3: Cellular Chemistry
Chemical bonding (examples?):
-Hydrogen Bonding between Water molecules.
-Covalent bonding between atoms w/in a water
molecule. Polar vs. non-polar?
Properties of water:
 Heat capacity
 Cohesive & adhesive
 Solvent: like dissolves like
-Ionic bonding between atoms w/ opposing
charges
o In humans: blood is mostly water w/ lots ‘o
dissolved solutes & a medium for the transport
of WBC & RBC
Organic Molecules: what elements? Subcomponents? Condensation & hydrolysis reactions?
I. Lipids: energy storage
phospholipids vs. fats vs. fatty acids
Steroids: big molecules with carbon rings
Differences vs. similarities
II. Carbohydrates
- monosaccharides vs. disaccharides vs. polysaccharides
-glucose polymers?
III. Proteins
 What is the structure of an amino acid? What makes each one unique?
o Peptide bonds between the AAs to form the proteins
 Condensation vs. hydrolysis reactions (think about linking amino acids together!)
 Levels of structure of proteins
o What causes the different levels?
o The structure of an amino acid?
 Types/examples of proteins?
o Enzymes: catalysts. Reduce rate of reaction.
 Factors affecting enzyme activity
 Inhibition:
(pH/Temp/Conc.)
 Competitive
 Anabolic vs. Catabolic
 Non-competitive
 Induced Fit model
 End product
 Mechanism of enzyme action
IV. Nucleic acids/nucleotides etc… (examples: DNA/RNA/ATP).
 General Structure consists of:
- single PO4 + Ribose + nitrogenous base (RNA)
- single PO4 + DeoxyRibose + nitrogenous base (DNA)
- three PO4 groups + Ribose + nitrogenous base (ATP)
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Be able to draw a nucleotide, double stranded DNA with antiparallel strands
Role of histones: protecting & packaging DNA
o If DNA wrapped around histones….a method of regulating transcription?
Types of sequence
o Exons (coding) vs. Introns
o An evolutionary reason to have lots (~98%) of non-coding DNA?
IB Biology Srs
Study Guide Test 2
Kerry Zimmerman
V. Replication: 5’ to 3’ (leading & lagging strands)
 Meselson & Stahl expts: semi conservative replication. Draw this?
 dNTP: deoxynucleoside triphosphate. Losing the two phosphate groups provides E for forming
bonds in the formation of DNA
 Figures 7.5 & 7.7. Know these
o Importance of replication bubbles…simultaneous replication
VI. Transcription.
 Where? Why? Which strand?
 Sense vs. antisense strand. Antisense is what is transcribed. So the sense strand is like?
 Promoter & terminator sequences
 Processing of transcript:
o Removal of introns prior to translation
o Cutting into separate mRNAs
VII. Translation: know Fig 7.12. 5’ to 3’.
 What is needed? Where does it occur?
 Ribosomes
o Subunits: large subunit with A,P, E binding sites
 Codons: AA & commands (start & stops)
 Phases
o Initiation: AUG, the start codon......read by ribosome…a tRNA w/ anticodon UAC binds to
mRNA/ribosome complex
o Elongation: tRNAs bring correct AA to form the protein
 Translocation: movement of tRNAs across ribosomal binding sites during elongation
o Termination: one of the stop codons in the mRNA in binding site A.
 A release factor (a protein) catalyses release of the tRNA in binding site P…releasing
the peptide.
Cellular Respiration: (overview stuff from Chapter 3).
Part I. Anaerobic Respiration
 Glycolysis (where does it happen? what is the result?)
 What is lactic acid (when might it build up on muscles?)
Part II. Aerobic Respiration
 Pyruvate > Acetyl CoA (oxygen present!) (Link reaction? where does this occur?)  Krebs cycle...Acetyl CoA plus 4 Carbon Oxaloacetate > 6 carbon Citrate
o What important molecules are produced here? Where does this cycle occur?
 Electron Transport Chain (H+ Buildup!! ADP turns into ATP via ATP Synthase)
o Where? Photosynthesis:
 Main products of the light reactions vs. The dark reactions
 Where do they occur?
 Effects of changing: temp, light intensity, carbon dioxide
IB Biology Srs
Study Guide Test 2
Kerry Zimmerman
IB Biology Srs
Study Guide Test 2
Kerry Zimmerman
 Essay Questions: answer to help you study? NO, I repeat No essays on
this test…but some short answer…and drawings…and m/c.
Essay #1
Part a. Please explain the basic structure of a DNA nucleotide. (draw a picture) How do we know which
end of the DNA double helix is the 3’ end and which end is 5’ end? Additionally, how does one side of the
DNA molecule serve as a template for the other side? semiconservative replication: how demonstrated by
Meselson & Stahl?
Part b. What is DNA replication? Why does it occur? In other words - why is it such an important process?
Describe the major steps involved in DNA Replication & the function of the enzymes we discussed in class
(DNA polymerase I, III, Helicase, Primase, LIgase). Form of the free nucleiotides? Be sure to thoroughly
compare and contrast continuous DNA replication & discontinuous DNA replication? (remember Okasaki
fragments - lagging strands)
Essay #2
Part 1 a. What is DNA transcription? Where and why does it occur? In other words - why is it such an
important process? Describe the major steps involved in transcription & explain how DNA serves as a
“Code” (or template)for the production of the building blocks of an organism. Think helicase to unwind and
RNA polymerase.
Part b. What is DNA translation? Where and why does it occur? In other words - why is it such an important
process? Describe the major components involved in translation & explain how mRNA codons play a vital
role in directing the synthesis of a very important type of organic molecule. Do not forget to thoroughly
explain what tRNA’s are and their vital role! Remember: mRNA, rRNA, tRNA, nucleotides, AA, codons,
anticodons
Essay #3
Part a. What are all organic molecules are comprised of, and where are organic molecules found? What
elements? Most of the atoms within organic molecules are bound together with covalent bonds...what is a
covalent bond? Why does such a bond form?
Part b. Explain the four main categories of organic molecules we discussed in class. What is the general
structure of each organic molecule made up of? (for example, what is the general structure of all
nucleotides, compared to the general structure of all proteins, etc.). Describe two (2) important functions for
each one of the four types of organic molecules.
Essay #4
Part a. What is the overall purpose of cellular respiration? In very simple terms, what is the relationship
between cellular respiration - which occurs in all heterotrophs and photosynthesis - which occurs in all
autotrophs.
Part b. Please outline the main steps of cellular respiration. Break this process up into two separate
processes anaerobic (or glycolysis) & aerobic respiration rxns. In each process be sure to emphasize the
main inputs and outputs (aka...products) What happens when NAD+ or FAD is reduced? What do they
bring to the electron transport chain? Flow charts, or labeled diagrams are very helpful!
Finally, ATP is main output of the electron transfer chain. What is the electron transfer chain, and where
does energy come from to operate this final phase of cellular respiration?
IB Biology Srs
Study Guide Test 2
Kerry Zimmerman