BIO 141 FINAL EXAM NEWEST ACTUAL QUESTIONS AND

BIO 141 FINAL EXAM NEWEST ACTUAL / QUESTIONS AND

ANSWERSVERIFIED/GRADED A+!!

DNA - -----Answers----Deoxyribonucleic acid, contains all info to build and maintain an organism -Ensures a certain level of continuity from one generation to another.

Eukaryotes - -----Answers---Organisms composed of cells that contain nuclei

Prokaryotes - -----Answers---Composed of cells that lack nuclei

Components of DNA - -----Answers---Composed of nucleotides

1) Nitrogenous Base: Adenine, Thymine, Guanine, Cytosine

2) Deoxyribose 3) Phosphate

Phosphodiester bond: - -----Answers---5' end attaches to 3' end of

adjacent nucleotide creates DNA's backbone

DNA Organization: - -----Answers----Double stranded, double helix,

-anti-parallel (one runs 3' to 5', the other 5' to 3')

DNA Packaging - -----Answers---Long pics of DNA are tightly looped, coiled and folded so they fit easily in a cell.-Eukaryotes wrap around histones to create chromatin 1 / 4

Karotype - -----Answers---Composite picture of chromosomes

Replication: - -----Answers---Process by which double-stranded DNA

is copied to produce 2 identical DNA molecules.

Steps:

1) Double helix is opened at origin (specific location of separation) by helicase 2) Priming of template strand. (primase) 3) Assembly of new DNA segment. (via DNA polymerase)

Helicase - -----Answers---Attaches to DNA strand and breaks hydrogen bonds between bases to open double helix.

Primase - -----Answers---Attaches to each strand and assembles the short stretch of nucleotides (primer)

DNA Polymerase - -----Answers---Wraps around strand and attaches new nucleotides to exposed nitrogen bases. (Relies upon pool of free- floating nucleotides to build new strand)

Anti-sequence - -----Answers---new strand exactly matched to complimentary strand.

RNA Polymerase - -----Answers---attaches to DNA template and begins assembling complimentary RNA strand

Transcription Factors - -----Answers---Proteins that help determine which DNA sequences should be transcribed. 2 / 4

Transcription Steps: - -----Answers---1) Initiation: RNA polymerase binds to specific area that facilitates transcription.

-Promoter region: "TATA box"

2) RNA polymerase moves 3' to 5' and creates mRNA -Uracil replaces Thymine, RNA is single-stranded 3) mRNA molecules carry message to ribosomes in cytoplasm where proteins are assembled.

Termination - -----Answers---When elongation ends and mRNA separates from DNA template via termination sequence or termination factor.

Introns - -----Answers---Noncoding nucleotides sequence -Clipped out post-termination

Poly-A tail - -----Answers---Sequence of Adenine is added to 3' end of mRNA

Purines - -----Answers---Guanine and Adenine, 2 rings linked by nine atoms

Pyrimidines - -----Answers---Cytosine, Uracil, Thymine, 1 ring linked by six atoms

RNA Primary Structure - -----Answers---Sugar-phosphate backbone, n-bases -OH groups make RNA less stable but can support catalytic activity

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RNA Secondary Structure - -----Answers---Hydrogen bonds occur on a single strand- folds on itself -Hairpin structure

RNA Tertiary Structure - -----Answers---When secondary structure folds into more complex shapes.

Gibbs free-energy change - -----Answers---ΔG=ΔH-TΔS -ΔG<0: exergonic: reactions are spontaneous -ΔG>0: endergonic: reactions are nonspontaneous -Entropy becomes more important as temperature of molecules increases.-Thermal energy increases amount of disorder.-Spontaneous chemical reactions run in the direction that lowers free energy in the system.

How do Temperature and Concentration affect reaction rates: - -----

Answers----When the concentration of reactants is high, more collisions occur and reactions should proceed more quickly -When temperature is high, reactants should move faster and collide more frequently again increasing rate of reaction.

Energetic Coupling - -----Answers---Chemical energy released from one reaction drives another.-Transfer of high-energy electrons or transfer of phosphate group.

ATP - -----Answers---Adenine triphosphate -Makes things happen because it has a great deal of potential energy -4 Negative charges that repel each other.

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