Question 1

Which concept describes the idea that the most closely related molecular sequences are those with the smallest number of differences between them?

Accepted Answer

Parsimony is a principle that suggests selecting the simplest explanation that fits the evidence. In molecular biology, parsimony is often used to determine the evolutionary relationships between species based on their molecular sequences. The idea that the most closely related molecular sequences have the smallest number of differences between them is a manifestation of parsimony.

Question 2

What kind of bond is formed between the 5′ phosphate group of one nucleotide and the 3′ hydroxyl (OH)group of the adjacent nucleotide?

Accepted Answer

The bond formation between the 5′ phosphate group of one nucleotide and the 3′ hydroxyl (OH)group of the adjacent nucleotide is called a phosphodiester bond.

Question 3

What is the process of synthesizing proteins from mRNA sequences?

Accepted Answer

The process of synthesizing proteins from mRNA sequences is called translation, during which ribosomes "read" the sequence of codons on the mRNA and use this information to string together a chain of amino acids that will fold into a functional protein. Replication involves copying DNA, transcription involves copying DNA into mRNA, transformation involves the transfer of genetic material between cells, and transduction involves the transfer of genetic material from one bacterium to another via a viral vector.

Question 4

Which term describes a set of organisms that descended from a single common ancestor and are more closely related to other members of the group than to organisms outside the group?

Accepted Answer

A monophyletic group is defined as a group of organisms that descended from a single common ancestor and includes all of the descendants of that ancestor. This group is also known as a clade and is considered to be a natural group, unlike a paraphyletic group which excludes certain descendants of the common ancestor. A phylogeny is a diagram that shows the evolutionary relationships between different organisms or groups of organisms, while a species is a group of organisms that can interbreed and produce viable offspring. Parsimony is a principle used in constructing phylogenetic trees that chooses the simplest explanation for the observed data.

Question 5

What is the process of synthesizing single-stranded RNA from template DNA?

Accepted Answer

Synthesizing single-stranded RNA from template DNA is the process of transcription.

Question 6

Which evolutionary process describes the movement of members of a species from one population to another?

Accepted Answer

Migration refers to the movement of individuals from one population to another, and is an evolutionary process that can result in gene flow and influence the genetic makeup of both populations. Natural selection, mutation, and random genetic drift involve changes in allelic frequencies within populations, while population genetics is the study of genetic variation and its distribution within and among populations.

Question 7

What kind of bond is formed between complementary base pairs to join the two DNA strands into a double helix?

Accepted Answer

Hydrogen bonds are formed between complementary base pairs to hold the two DNA strands together in a double helix structure.

Question 8

Which enzyme is active in DNA replication?

Accepted Answer

DNA replication involves the creation of a new strand of DNA complementary to the original template strand. DNA polymerase is the enzyme responsible for catalyzing the formation of the new DNA strand by adding nucleotides in a specific sequence dictated by the template DNA strand.

Question 9

Which evolutionary process involves the slow addition of allelic variation that increases the hereditary diversity of populations,ultimately leading to evolutionary change?

Accepted Answer

Mutation is the process that introduces new alleles into a population, thus increasing genetic variation. This can lead to evolutionary change over time as new traits are introduced and selected for or against by other evolutionary processes such as natural selection or genetic drift.

Question 10

What kind of bond is formed between successive amino acids during translation?

Accepted Answer

Peptide bonds are formed between the carboxyl group (-COOH) of one amino acid and the amino group (-NH2) of the next amino acid during translation. This involves a dehydration synthesis reaction in which a water molecule is released, resulting in the formation of a covalent peptide bond.  Ionic bonds involve the attraction between charged ions, phosphodiester bonds form between nucleotides in DNA/RNA, and disulfide bonds form between the sulfhydryl groups (-SH) of two cysteine residues in a protein. Hydrogen bonds, while important in protein structure, do not form between successive amino acids.

Question 11

You identify a new unicellular organism with multiple chromosomes organized by proteins within the cell's nucleus.Into which of the three domains of life might this organism fit?

Accepted Answer

The presence of multiple chromosomes organized by proteins within the cell's nucleus is a defining characteristic of eukaryotic cells, which belong to the domain Eukarya. Therefore, the best choice for this organism is C.

Question 12

Modern genetics consists of three major branches.Which of these branches,also known as "transmission genetics," involves the study of the transmission of traits and characteristics in successive generations?

Accepted Answer

Mendelian genetics, also known as "transmission genetics," involves the study of the transmission of traits and characteristics in successive generations according to the laws of inheritance discovered by Gregor Mendel. The other branches of modern genetics include molecular genetics, which focuses on the structure and function of genes at a molecular level, and population genetics, which studies the genetic makeup of populations and how genetic variation changes over time.

Question 13

The promoter is bound by the transcription factors and which enzyme?

Accepted Answer

The enzyme bound by the promoter and transcription factors is RNA polymerase, which is responsible for synthesizing the mRNA molecule during transcription. DNA polymerase is involved in DNA replication, reverse transcriptase is an enzyme found in retroviruses, DNase and RNase are enzymes that break down DNA and RNA, respectively.

Question 14

Watson and Crick used evidence from several studies to determine the structure of DNA.What conclusion were they able to draw from Rosalind Franklin's X-ray diffraction data,specifically?

Accepted Answer

Rosalind Franklin's X-ray diffraction data provided evidence that DNA was a double helix structure made up of two strands, which Watson and Crick were able to determine were held together by base pairing (adenine with thymine, and cytosine with guanine). This led them to their conclusion that DNA is a duplex, with two strands forming a double helix.

Question 15

Which evolutionary process relies on the premise that individuals with the best adaptations are most successful at reproducing and leave more offspring than those with less adaptive forms?

Accepted Answer

This process is known as natural selection, where individuals with better adaptations have a higher chance of survival and reproducing, leading to the passing on of those advantageous traits to future generations.

Question 16

Which evolutionary process is most pronounced in small populations where statistical fluctuations in allele frequencies can be significant from one generation to the next?

Accepted Answer

Random genetic drift is most pronounced in small populations where statistical fluctuations in allele frequencies can be significant from one generation to the next. This is because there are fewer individuals and therefore, chance events such as deaths, births or mating choices can have a greater impact on the gene pool of the population. Natural selection, migration, and mutation are also factors that can influence the evolution of a population, but random genetic drift is particularly important in small populations. Population genetics is a field of study that encompasses all of these factors in understanding the evolution of populations.

Question 17

When a diploid cell divides by mitosis,the result is

Accepted Answer

Mitosis is a process of cell division that results in two identical diploid cells, each containing the same number of chromosomes as the parent cell. Therefore, option B is the correct answer. Options A and C are incorrect because mitosis does not result in haploid cells. Option D is incorrect because mitosis does not produce unique cells, rather, they are identical to the parent cell. Option E is incorrect because mitosis does not result in haploid cells.

Question 18

Sexual reproduction uses meiosis to generate

Accepted Answer

Sexual reproduction uses meiosis to generate four unique haploid gametes, each containing half the number of chromosomes as the parent cell. This allows for genetic diversity and the possibility of offspring with different characteristics than the parents. Options A and B are incorrect because identical gametes would not lead to genetic diversity. Option C is incorrect because generating identical gametes would defeat the purpose of meiosis to generate variability. Option D is incorrect because diploid gametes would result in zygotes with double the normal number of chromosomes.

Question 19

Which type(s)of RNA is/are translated into proteins?

Accepted Answer

Only messenger RNA (mRNA) is translated into proteins. Ribosomal RNA (rRNA) is a major component of ribosomes, which facilitate the translation process, but rRNA molecules themselves are not translated into proteins. Transfer RNA (tRNA) molecules also play a role in translation by carrying amino acids to the ribosome, but they are not directly translated into proteins either.

Question 20

Bacteria are single-celled organisms with a single chromosome found in which cell space?

Accepted Answer

Bacteria lack a true nucleus and instead have a region called the nucleoid where their single chromosome is found.

Quiz 1: The Molecular Basis of Heredity, Variation, and Evolution