Saturday, December 11, 2010

Answers to Mastering Biology - Biology 100

02. Introduction to Biology
Chapter 1 Reading Quiz Question2
Q: In Pasteur's experiment, the purpose of the swan neck on the flask was to _____.
A:  trap cells from the air before they reached the growth mediu

Chapter 1 Reading Quiz Question 3
Q: Pasteur's results showed that _____.
A: when growth medium is not contaminated by preexisting cells, the growth medium remains sterile

03. Chemistry
Activity: Covalent Bonds
Q: What type of bond is joining the hydrogen 2 atoms?
A: Covalent
Q: A(n) _____ refers to two or more atoms held together by covalent bonds.
A: molecule
Q: This atom can form up to _____ single covalent bond(s).
A: 4
Q: A(n) _____ bond joins these two oxygen atoms.
A: double covalent

Chapter 2 Blue Thread Question 1
Q: Which of the following statements most accurately describes the relative locations of the covalently bonded electrons in methane ({\rm CH_4}) and ammonia ({\rm NH_3})?
A: Electrons are shared equally in {\rm CH_4} and unequally in NH3.

Activity: Nonpolar and Polar Molecules
Q: Which of these figures correctly illustrates the nature of the bonding of H2O?
A: The correct answer is the illustration where oxygen atom is negative and the hydrogen atoms are positive.
Q: What type of bond joins the carbon atom to each of the hydrogen atoms?
A: single (nonpolar) covalent

Chapter 2 Question 6
Q: You isolate a molecule and determine it is nonpolar. Based on this property, the molecule is largely composed of the elements _____.
A: carbon and hydrogen

Activity: Dissociation of Water Molecules
Q: What name is given to this molecule?
A: hydronium ion
Q: How did this molecule form?
A: A water molecule gained an hydrogen ion from another water molecule.
Q: What name is given to this molecule? (There is one oxygen and one hydrogen atom)
A:  hydroxide ion
Q: Click on the diagram to begin the animation. This animation illustrates the _____ of water. 
A:  dissociation
Q: Which of these is the correct equation for the dissociation of water? 
A: H2O + H2O <==> H3O+ + OH-
Q: What is the charge of a hydronium ion?
A: 1+
Q: What is the charge on a hydroxide ion? 
A: 1-
Q: About _____ molecules in a glass of water are dissociated. 
A: 1 in 500,000,000

Activity: Hydrogen Bonds
Q: The brackets are indicating a(n) _____ bond.
A: hydrogen
Q: What name is given to the bond between water molecules? 
A: hydrogen

Chapter 2 Question 26
Q: To act as an effective coolant in a car's radiator, a substance has to be a liquid at the temperatures found in your car's engine and have the capacity to absorb a great deal of heat. You have a reference book with tables listing the physical properties of many liquids. In choosing a coolant for your car, which table would you check first?
A: specific heat

Carbon Bonding and Functional Groups
Q: Which molecules show an appropriate number of bonds around each carbon atom?
A: 3 apply- the molecule that has the circular structure, the molecule that has a double bond between 2 carbon atoms in it, and the one with only one oxygen atom.
Q: The molecule shown here contains four functional groups. Highlight all the atoms of the four functional groups by clicking on them. When you click on each atom, it will change color. To deselect an atom, click on it again. Do not highlight any bonds.
A: There are a total of 11 atoms you are going to need to highlight. The H and the S all the way to the left, The O and H that extend off the top of the molecule, the N and 2 H's that branch off of the right of the molecule, the phosphate group on the bottom consisting of one P and 3 O's.
Q: Functional groups confer specific chemical properties to the molecules of which they are a part. In this activity, you will identify which compounds exhibit certain chemical properties as well as examples of those six different compounds. Drag one molecule (white label) and one chemical property (blue label) to each bin.
A: Alcohol will need the molecule where one O and one H is highlighted and "is highly polar and may act as a weak acid". Carboxylic acid will need the molecule where 2 O's a C and an H molecule are highlighted, also "acts as an acid". Aldehyde needs the molecule where 1 O and 1 C atom are highlighted and "may be a structural isomer of a ketone". Thiol will need the molecule where and S and an H atom are highlighted and "forms disulfide bonds". Amine will need the molecule where an N and 2 H molecules are highlighted and "acts as a base". Organic Phosphate will need the molecule with 1 P and 4 O atoms and "contributes negative charge".

Chapter 2 Blue Thread Question 8
Q: Which list shows the correct positions of the molecules on an electron-sharing continuum, with equal sharing on the left and no sharing (i.e., transfer of electrons) on the right?
A: O2, CO2, CaCl2

Chapter 3 Blue Thread Question 2
Q: The figure illustrates a reaction between two amino acid monomers that produces a "dipeptide." What type of reaction is shown and what kind of bond is formed between the two monomers?
A: a condensation reaction that forms a covalent bond

Chapter 3 Blue Thread Question 3
Q: Each of the figures above represents a peptide with three amino acids linked together (a "tripeptide"). In which figure are the N-terminus, C-terminus, Amino Group, and Carboxyl Group correctly labeled?
A: The answer is the molecule where N-terminus is in the top left corner and Amino Group is in the bottom right corner.

Chapter 3 Question 20
Q: You disrupt all hydrogen bonds in a protein. What level of structure will be preserved? 
A: primary structure

Amino Acid Functional Groups
Q: Classify these amino acids as acidic, basic, neutral polar, or neutral nonpolar. Drag each item to the appropriate bin.
A: The acidic bin will have none. The basic bin will have arginine. The neutral polar bin will have asparagine, cysteine, and glutamine. The neutral nonpolar will have Alanine.
Q: Classify these amino acids as acidic, basic, neutral polar, or neutral nonpolar.
Drag each item to the appropriate bin.
A: Acidic - none. Basic - lysine. Neutral Polar -  serine. Neutral nonpolar - proline, phenylalanine, methionine.
Q: Classify these amino acids as acidic, basic, neutral polar, or neutral nonpolar. Drag each item to the appropriate bin.
A: Acidic - glutamic acid. basic - none. neutral polar - tyrosine, threonine. neutral nonpolar - tryptophan, valine.

Chapter 3 Reading Quiz Question 6
Q: Which of the following statements about the primary structure of a protein is true? 
A: Primary structure is produced by the unique sequence of amino acids in a protein. 
Chapter 3 Question 22
Q: When polymerization of a protein is complete, but the protein is still completely linear, what is the highest level of structure that has been completed? 
A: primary
04. Mitosis, meiosis, genetics 

The Phases of Mitosis
Q: Which event does not take place before the start of mitosis?
A: The nuclear envelope disintegrates.
Q: True or false? Mitosis takes place during M phase, which is the longest phase of the cell cycle.
A: False.
Q: Which term describes two recently replicated DNA strands that are joined together just before cell division?
A:  Sister chromatids 
Q: During which stage of mitosis are chromosomes lined up in the center of the cell?
A: Metaphase
Q: Which stage of mitosis is characterized by the disintegration of mitotic spindles and the formation of two new nuclear membranes?
A: Telophase
Q: To which part of the centromere do mitotic spindle fibers attach during prometaphase?
A: Kinetochore
Q: During which substage of mitosis do sister chromatids break apart and start moving to opposite poles of the cell?
A: Anaphase

 Chapter 11 Reading Quiz Question 2
Q: During what phase of the cell cycle does the DNA become replicated?
A: S

Activity: Cell Cycle
Q: Which of these phases encompasses all of the stages of mitosis?
A: E
Q: During _____ both the contents of the nucleus and the cytoplasm are divided.
A: the mitotic phase
Q: During _____ the cell grows and replicates both its organelles and its chromosomes.
A: interphase

Chapter 12 Blue Thread Question 1
Q: For the male lubber grasshopper shown in the figure what are the (1) haploid number, (2) ploidy, and (3) total number of chromosomes?
A: (1) 12; (2) 2n; (3) 23 

Chapter 12 Reading Quiz Question 1
Q: A non-sex chromosome is _____.
A: an autosome 

Chapter 12 Reading Quiz Question 4
Q: In an organism in which 2n = 6, how many chromosomes will be in each gamete?
A: 3

Chapter 12 Question 1
Q: Which of the following processes contributes directly to genetic variation?
A: meiosis

Chapter 12 Blue Thread Question 6
Q: Which statement is FALSE concerning gametes produced by meiosis?
A: Gametes contain nonrandom combinations of maternal and paternal chromosomes. 

Chapter 12 Blue Thread Question 10
Q: For species that alternate between sexual and asexual reproduction, which statement is most accurate?
A: Sexual reproduction is common when environmental conditions are changing rapidly. 

Chapter 13 Question 1
Q: Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6022 yellow and 2001 green (8023 total). The allele for green seeds has what relationship to the allele for yellow seeds?
A: recessive

Chapter 13 Question 9
Q: Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. (a) What is the most probable genotype of each parent? (b) Based on your answer in (a) above, what genotypic and phenotypic ratios are expected in these progeny? (Assume the following symbols: G = gray and g = white.)
A: (a) Gg × Gg; (b) genotypic = 1:2:1, phenotypic = 3:1 

Chapter 13 Blue Thread Question 1
Q: In peas, the allele for yellow seeds (Y) is dominant to the allele for green seeds (y). What would be the genotype and phenotype ratios of offspring from a cross between Yy and yy individuals?
A: Genotype: ½ Yy : ½ yy; Phenotype: ½ yellow : ½ green 

 Chapter 13 Blue Thread Question 3
Q: Assuming independent assortment, an individual of genotype SsYyAa would produce gametes of what genotypes (in their correct proportions)?
A: 1/8 SYA, 1/8 SYa, 1/8 SyA, 1/8 Sya, 1/8 sYA, 1/8 sYa, 1/8 syA, 1/8 sya  

05 Nucleic Acids, DNA 

 Activity: Structure of RNA and DNA
Q: Which structure is not a component of a nucleotide?
A: Sulfhydryl Oxygen group 

Which of the following statements about nucleotide structure is false?
A: The phosphate group is bonded to the nitrogenous base. 
Q: True or false? Guanine and uracil are examples of nitrogenous bases.
A: True
Q: Which linkage forms the backbone of a nucleic acid?
A: A sugar-phosphate linkage 
Q: Which of the following statements about DNA structure is true?
A: The nucleic acid strands in a DNA molecule are oriented antiparallel to each other.   
Q: What is the complementary DNA sequence to 5’ ATGCATGTCA 3’?


  1. i love you! biology is a pain in my butt right now, i have 300 questions due by sunday RIGHT BEFORE FINALS and were barely assigned this week. thanks so much for destressing me.

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