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Exam- BIO 251 |415 Exam Questions with Complete Solutions 100% Solved
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Exam- BIO 251 |415 Exam Questions with Complete Solutions 100% Solved
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Exam- BIO 251 |415 Exam Questions with CompleteSolutions 100% Solved
Name five fundamental characteristics shared by all living organism. Correct Answer-1.
Cells
2. Energy consumption
3. Information
4. Replication
5. Evolutionary adaptation
Describe the two components of cell theory. Correct Answer-1. All living things are made
up of cell or cells.
2. Cells come from other cells.
Define energy, and describe the major forms it can take. Understand in what way chemical
bonds can be considered a form of energy. Correct Answer-Energy is the capacity to do
work or to supply heat. Potential energy- may be stored. Kinetic energy- may be available in
the form of motion. When chemical bonds are formed, energy is released. The internal energy
of the system goes down
, Exam- BIO 251 |415 Exam Questions with Complete
Solutions 100% Solved
Explain, both in mathematical terms and in plain English, how changes in entropy and
potential energy determine whether or not a reaction is spontaneous. Understand under
what conditions a nonspontaneous reaction can occur. Correct Answer-ΔG(ibbs free
energy) = ΔH (enthalpy) - T ΔS (entropy)
If ΔG is negative (big loss of potential energy, and/or big gain of disorder): the reaction is
Exergonic (Exit of energy). SPONTANEOUS
If ΔG is positive (big gain of potential energy, and/or big loss of disorder): the reaction is
Endergonic (Input of energy). NOT SPONTANEOUS
Explain and give examples of why proteins are essential to cell function. Correct Answer--
Enzyme Catalysis (chemistry)
-Cell receptors (signalling and immune response)
-Transport (food uptake, e.g.)
-Support (cell/organism structure)
-Motion (muscles, flagella)
-Regulation (gene expression)
, Exam- BIO 251 |415 Exam Questions with Complete
Solutions 100% Solved
Sketch the basic structure of an amino acid, and describe why and how the side chains affect
the function and structure of each amino acid. Correct Answer-Structure: Central carbon
atom bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom and in
the 4th position, a side group (R-Group). The side chain is the chemical identity to the amino
acid and extends out from the backbone, making it possible for them to interact with each
other and with water. (Visual representation: slide 4)
Sketch a nucleotide, label its three basic parts, and identify the 2', 3', and 5' carbons.
Correct Answer-A nucleotide has a sugar or deoxyribose group, a phosphate that is
attached on the 5' carbon and an organic nitrogenous base which is attached to the 3' carbon.
Ribose has an -OH on the 2' carbon, Deoxyribose has a H' on the 2' carbon.
Describe the primary, secondary, tertiary, and quaternary structures of RNA, and explain in
what ways RNA differs from DNA. Correct Answer-RNA's primary structure consists of a
sequence of nitrogen-containing bases that contain information in the form of a molecular
code. Its secondary structure includes short double helixes and structures called hairpins that
holds RNA strands together. Its tertiary and quaternary structures that fold secondary
structures into complex shapes or hold different RNA strands together. RNA has Uracil instead
, Exam- BIO 251 |415 Exam Questions with Complete
Solutions 100% Solved
of Thymine, it is single stranded, its ribose has an extra -OH group, and it acts as a transcript
of DNA expression. Also, DNA does not have a tertiary and quaternary structure.
Explain why and how the secondary structure of DNA allows organisms to store and copy
information. Correct Answer-Complementary base pairing allows each strand of a DNA
molecule to be copied exactly, producing two daughter molecules. DNA's primary structure
serves as a mold or template for the synthesis of a complementary strand and DNA contains
the information required for a copy of itself to be made
Explain why RNA, and not DNA, was probably the first self-replicating molecule, and describe
at least one piece of experimental evidence that supports this hypothesis. Correct Answer-
To make a copy of itself, the first living organism had to provide a template that could be
copied and catalyze polymerization reactions that would link monomers into a copy of that
template. RNA is capable of both.
One experimental evidence is by Wendy Johnston and David Bartel. They found that
ribozymes isolated in each round are copied, the molecules that result are not identical in
terms of their primary sequence because mutations were introduced during the copying step.
By isolating the best enzyme and copying them in the next round, they continually selected
ribozymes that were more efficient. This was to mimic the process of natural selection
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