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BIOS 251 Test
- Name five fundamental characteristics shared by all living organism.
- Cells
- Energy consumption
- Information
- Replication
- Evolutionary adaptation
- Describe the two components of cell theory.
- All living things are made up of cell or cells.
- Cells come from other cells.
- Define energy, and describe the major forms it can take. Understand in what way chemical
- Explain, both in mathematical terms and in plain English, how changes in entropy and
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bonds can be considered a form of energy.–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
potential energy determine whether or not a reaction is spon- taneous. Understand under what conditions a nonspontaneous reaction can occur.–Answer ”G(ibbs free energy) = ”H (enthalpy) - T ”S (entropy) If ”G is negative (big loss of potential energy, and/or big gain of disorder) –Answer the reaction is Exergonic (Exit of energy). SPONTANEOUS If ”G is positive (big gain of potential energy, and/or big loss of disorder) –Answer the reaction is Endergonic (Input of energy). NOT SPONTANEOUS 1 / 4
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- Explain and give examples of why proteins are essential to cell function.
- Sketch the basic structure of an amino acid, and describe why and how the side chains affect
–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)
the function and structure of each amino acid.–Answer Structure –Answer 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 –Answer slide 4)
- Sketch a nucleotide, label its three basic parts, and identify the 2', 3', and 5' carbons.
- Describe the primary, secondary, tertiary, and quaternary structures of RNA, and explain in
–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.
what ways RNA differs from DNA.–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 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. 2 / 4
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- Explain why and how the secondary structure of DNA allows organisms to store and copy
- Explain why RNA, and not DNA, was probably the first self-replicating mol- ecule, and
- List the features shared by all carbohydrates.
- Sketch several representative monosaccharides, illustrating three ways in which
- Give examples of the four major functions that carbohydrates can perform in cells (raw
information.–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
describe at least one piece of experimental evidence that supports this hypothesis.–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
–Answer A molecule made up of a bunch of carbon, hydrogen, and oxygen. These atoms are arranged in a few specific ways –Answer they have a carbon atom that's bonded to a carbonyl group (>C=O), several hydroxyl functional groups (-OH), and many C-H bonds.
monosaccharides can differ from one another.–Answer Monosaccharide have a carbonyl group at various locations , several hydroxyl functional groups at variouslocations, and many carbon-hydrogen (C-H) bonds (energy). Linear form, ring form, alpha vs beta form.
materials, structure, cell identity, and chemical energy storage).-
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Raw materials –Answer Sugars frequently furnish the raw "carbon skeletons" that are used as a building blocks in the synthesis of important molecules. Amino acids use sugars as a starting point.Structure –Answer Cellulose and chitin, along with modified polysaccharide peptidoglycan, are key to structural compounds. They form fibers that give cells and organisms strength and elasticity.Cell identity –Answer Enormous number of structurally distinct monosaccharides make it possible for an enormous number of unique oligosaccharides to exist. As a result, each cell type and each species can display a unique identity Chemical energy storage –Answer Kinetic energy in sunlight is converted to chemical energy stored in bonds of carbohydrates by photosynthesis.
- Sketch a phospholipid's molecular structure, and explain why phospho- lipids
- Predict which way a certain substance will diffuse, given its concentration on either side of
- Describe at least three ways in which membrane proteins can help sub- stances cross a cell
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spontaneously form bilayers in water.–Answer Phospholipids have polar ends and nonpolar tails. The hydrophobic tails on the phospholipid molecules react with one another, and are repelled by water. The polar head groups on the phospholipids are hydrophilic and react with water. For these reasons, the phospholipids organize themselves in such a way as to maximize the hydrophobic and hydrophilic interac- tions. The form that accomplishes this the best is a bilayer.
a selectively permeable membrane.–Answer If a solution is hypertonic (the solution surrounding the cell has higher concentration of solutes) water will rush out of the cell, shrinking it. If a solution is hypotonic, (the solution surrounding the cell has less concentration of solutes) water will rush into the cell, enlarging it. If a solution is isotonic, (the concentration of solute is the same inside and outside the cell) the water stays as is.
membrane.