Exam 3

chapter 10 -

Using the terms helicase, primase, leading and
lagging strand, DNA polymerase, and Okazaki
fragments, describe the DNA replication process.

DNA replication is a complex process crucial for the accurate duplication of genetic information within a cell. It begins at specific origins of replication where helicase enzymes unwind the DNA strands, creating two templates for synthesis. Primase then lays down RNA primers on both the leading and lagging strands. The leading strand is synthesized continuously by DNA polymerase III, which adds nucleotides in the 5' to 3' direction. However, the lagging strand is synthesized discontinuously in short fragments called Okazaki fragments, as DNA polymerase can only work in the 5' to 3' direction. DNA polymerase I replaces the RNA primers with DNA on the lagging strand, and DNA ligase joins the Okazaki fragments together. This organized process results in two identical DNA molecules, each composed of one original and one newly synthesized strand, ensuring genetic fidelity during cell division.

Skin color is coded for by several different genes which results in a range of skin colors from very dark to very light. This is an example of

 polygenic inheritance.

What does true-breeding mean?

When the plant self-pollinates, all the offspring resemble the parent, and are homozygous for that gene.

 

When the plant self-pollinates, all the offspring resemble the parent, and are homozygous for that gene.

1. The plants were easy to grow.

2. Pea plants can either cross-pollinate or self-pollinate.

3. All inheritance patterns were simple.

4. The traits studied had no intermediate characteristics.

The information in a Punnett square represents

all possible combinations of gametes based on a cross between two parents.

If a true-breeding tall pea plant is crossed with a tall pea plant of unknown parentage, which of the following is correct?

Some short individuals may appear in the F₂ generation.

In a dihybrid cross, how many traits are examined?

2

Which of the following is true with regards to the law of independent assortment?

Each pair of alleles assorts independently of the other allele pairs.

Alleles are

 alternate versions of the same gene.

Which of the following is mismatched?

identical alleles - heterozygous

What are all possible gametes that can be produced by an individual with the following genotype: FFGg?

FG, Fg

During meiosis, each pair of alleles on the homologous chromosomes sorts independently from all other pairs of alleles. This statement corresponds to

the law of independent assortment.

A heterozygote trait exhibiting incomplete dominance will

express an intermediate phenotype.

Determine if the following statement is true or false. A man with blood type A and a woman with blood type B can have a baby with blood type O.

True, because although A and B are the dominant blood types, both individuals could carry a type O allele.

Which of the following is an inaccurate statement about human blood types?

Human blood genetics involves multiple alleles and an individual can have up to three different blood alleles.

A woman with type AB blood marries a man who is heterozygous for type B blood. If they have children, what are all the possible blood types for the children?

AB, BB, AO, and BO

Which of the following is a true statement?

Females can be heterozygous for sex-linked traits.

Red-green color blindness is a recessive X-linked trait. If a female is red-green color-blind, which of the following is true?

Her father must be color-blind.

What is the inheritance pattern of hemophilia?

sex-linked recessive

Which of the following is mismatched?

anther - female

If a heterozygous dominant tall pea plant is crossed with a short pea plant, what is the expected phenotypic ratio?

1 tall:1 short

tRNAs carrying the correct amino acid recognize the proper codons on the mRNA because

 the anticodon of the tRNA hydrogen binds to the codon of the mRNA by complementary base pairing.

Before leaving the nucleus, mRNA is modified by

 the addition of a guanine cap to the 5’ end.

During transcription

DNA is transcribed into mRNA

According to Chargaff's data,________ must pair with________, and________ must pair with________.

A; T; C; G

The term semiconservative refers specifically to

DNA replication

There are three steps that are required for DNA replication. The first step, unwinding, is accomplished by the enzyme

helicase

Which of the following enzyme is needed to reseal breaks in the sugar-phosphate backbone during replication?

 DNA ligase

For a DNA strand that contains the sequence AGT in the 5' to 3' direction, what nucleotides are found on the other DNA strand in the 5' to 3' direction?

ACT

DNA replication is called semiconservative because

each resulting DNA molecules is comprised of one new DNA strand and one old strand.

A defect in DNA ligase would most likely result in

 normal replication, but gaps remaining in the sugar-phosphate DNA backbone.

Which base is found in DNA, but not in RNA?

 

thymine

If RNA polymerase malfunctions,

 

mRNA will not be formed.

DNA serves as a template for the formation of________ during a process called transcription.

mRNA

Using three bases to represent each amino acid in a polypeptide

 

ensures that all amino acids are represented at least once by the code.

The stages of translation are

 

initiation, elongation cycle, and termination.

DNA replication makes a(n)________ copy of the DNA strand, while transcription makes a(n)________ copy of the DNA strand.

 

DNA; mRNA

The sequence of the mRNA that would result from transcribing a segment of a DNA template strand with the bases AATAGCGTA would be

 

UUAUCGCAU.

The two DNA strands must be separated before

 

both DNA replication or transcription can occur.

Transcription activators are different from transcription factors in that

 

transcription factors are required for RNA polymerase binding, while transcription activators accelerate transcription.

Prokaryotes regulate gene expression at which of the following levels?

 

mRNA transcription only

In order to clone adult animals, scientists typically begin with a(n)

 

enucleated egg.

Reproductive cloning results in________ while therapeutic cloning results in________.

 

an identical organism; various types of mature cells

Why is it necessary to "starve" the donor cells prior to reproductive cloning?

to force the cells into G₀ stage so that they will respond to cytoplasmic growth signals

Specialized cells differ from one another because they

 

only express certain genes.

Which of the following sequences of events in the production of recombinant DNA are in the correct order?

 

cut DNA with restriction enzymes, mix DNA with plasmid DNA, add DNA ligase

DNA ligase

 

links two DNA molecules together.

The steps involved in a single PCR cycle, in the correct order, are

 

heat to denature DNA strands, cool to allow primer to anneal, allow DNA polymerase to copy DNA.

In 2019 a 35-year-old cold case murder in Wisconsin was solved using a DNA profile of the perpetrator. Which of the following forms of biotechnology made this possible?

 

DNA fingerprinting

________ is the study of the structure and function of cellular proteins and their interactions;________ may be employed to use computer algorithms to aid this process.

 

Proteomics; bioinformatics

Which of the following is used to cleave DNA in order to create recombinant DNA?

 

restriction enzymes

Which of the following is used to insert the foreign gene when creating recombinant DNA?

 

a vector

After 15 PCR cycles, how many DNA strands would be available?

 

32,768

The study of comparative genomics has given researchers the ability to look at multiple genomes from different species, which has lead to new ideas about the evolutionary history of organisms. The conclusion is that

 

the genomes of all modern vertebrates are surprising more similar than expected.

Organisms that have had foreign genes inserted into them are called

 

transgenic organisms.

What does the field of proteomics study?

 

The structure and function of cellular proteins and how they interact to contribute to traits.

There are several methods of gene editing, including________, the most widely used method.

 

CRISPR

The CRISPR system involves the Cas9 enzyme, which identifies specific nucleotides to be cut using a(n)________ molecule as a guide to identify the proper DNA sequence to edit.

 

RNA

STR is a useful technique for creating a DNA profile because it

 

creates short sequences of DNA that are unique to every individual.

The study of all the genes and the regions between genes, in all types of organisms is known as

genomics

The regions of DNA between genes is known as

 

intergenic DNA.

Using the following terms describe the process of transcription and translation: RNA polymerase, mRNA, exon, codon, tRNA, ribosome, and amino acid.

Transcription is the process of synthesizing mRNA from a DNA template using RNA polymerase. The RNA polymerase binds to the DNA and separates the strands. It then adds complementary RNA nucleotides to form the mRNA molecule. Exons are the coding regions of the mRNA that will be translated into proteins.

Translation is the process of synthesizing proteins from mRNA. The mRNA is read in groups of three nucleotides called codons. Each codon codes for a specific amino acid. Transfer RNA (tRNA) molecules carry the corresponding amino acids to the ribosome, where they are joined together to form a protein. The ribosome acts as the site of protein synthesis. Amino acids are the building blocks of proteins and are joined together in a specific order determined by the sequence of codons in the mRNA.

what are the steps of PCR (polymerase chain reaction)? (process)

PCR (Polymerase Chain Reaction) is a technique used to amplify a specific DNA sequence in a sample. The process involves several steps. First, denaturation occurs, where the DNA sample is heated to separate the double-stranded DNA into single strands. Next, annealing occurs, where the temperature is lowered to allow the primers to bind to the specific target sequences on the DNA. Then, extension occurs, where DNA polymerase synthesizes new DNA strands by extending from the primers. Finally, the process is repeated multiple times (usually 20-40 cycles) to amplify the DNA exponentially. These steps enable scientists to obtain a large amount of a specific DNA sequence for further analysis or experimentation.

using the following terms: Coding genes, Non-coding DNA (STR), Restriction enzymes, Polymerase Chain Reaction, Electrophoresis, and Fingerprint, describe how DNA fingerprinting works.

DNA fingerprinting, also known as DNA profiling, is a technique used to identify individuals based on their unique DNA patterns. It involves extracting DNA from a sample, such as blood or saliva. Polymerase Chain Reaction (PCR) is then used to amplify specific regions of DNA, including coding genes and non-coding DNA regions called Short Tandem Repeats (STRs). Restriction enzymes are used to cut the amplified DNA into smaller fragments at specific recognition sites. These fragments are separated based on size using electrophoresis, creating a unique pattern or "fingerprint" for each individual. By comparing the DNA fingerprints of different individuals, scientists can determine if they share common genetic markers or if they have distinct patterns. This technique is widely used in forensic science, paternity testing, and genetic research.

Which of the following concepts would Charles Lyell have supported?

 

the Earth slowly changes through time

Although Lamarck hypothesized that adaptations to the environment did occur, he also believed that

offspring inherited characteristics that were acquired by their parents during their lifetime.

Lyell's Principles of Geology was the first text to give evidence that the Earth

was undergoing slow and continuous cycles of erosion and uplift.

Lyell's theory of uniformitarianism stated that

the processes that shape the Earth occur at a constant rate.

Darwin’s ideas on evolution by natural selection included ideas that were not generally accepted by scientists or society at that time. One such idea was that

the Earth is very old.

Wings of insects and birds are results of convergent evolution. This means that

insects and birds have each independently evolved structures that serve the same function (flight) but have done so in very different ways.

Darwin’s visit to the Galápagos Islands played a fundamental role the development of his theory of evolution by natural selection. Which of the following observation(s) would have been important in the development of his theory?

1. Each island had a unique environment, and the environment of each island was different from the mainland environment.

2. The islands were too far from mainland South America for most terrestrial plants and animals to colonize.

3. The organisms on the islands were different from those observed in South America.

Tortoises in the Galápagos possessed neck lengths unique to each island. Neck lengths appear to be an adaptation to which selective agent?

type of vegetation available to eat

Alfred Wallace’s research led him to discover a series of islands that could be divided into a western group, with organisms similar to those seen in Asia, and an eastern group with organisms similar to those seen in Australia. The line of division between the eastern and western islands, known as Wallace’s Line, was created by a(n)________ that prevents migration between the two groups of islands.

deep sea straight

What influence did the writings of Thomas Malthus have on Darwin's ideas of natural selection?

Malthus proposed that the human population grows faster than the food supply, meaning that death and famine are inevitable.

In the context of natural selection, fitness refers to

reproductive success.

The presence of vestigial organs supports evidence of evolution because

the vestigial organ is similar to a functional organ in a related species, having been passed down from a common ancestor.

________ structures are evidence of common ancestry, while________ structures serve a similar function but are not constructed similarly, and therefore could not have a common ancestry.

Homologous; analogous

The wing of a penguin and the wing of an eagle are

homologous structures.

The similarity of the fossil glyptodont to the living, modern armadillo is an example of which line of evidence that supports the theory of evolution?

anatomical

Many people refer to Alfred Russel Wallace as the "father of biogeography." Which of the following contributions led Wallace to achieve this title?

Wallace described a sharp line dividing Australian species from Asian species.

Natural selection results in

offspring that are better adapted to their current environment.

The theory of evolution is

supported by multiple sources of evidence described by many different researchers, and by a variety of fields of study.

Darwin and Wallace both concluded that species evolve through the process of natural selection. What similar experiences and information helped them both reach the same conclusion?

1. Both traveled the world and collected specimens.

2. Both were familiar with the writings of Malthus.

3. Both were naturalists.

Which of the following information cannot be determined from the fossil record?

Evidence of every species that ever existed.

In regards to natural selection, which of the following individuals would be considered the most fit?

 

the individual that has the greatest number of offspring

All of the following generate genetic variation within a population except

 

mitosis.

Which of the following examples describes genetic drift?

 

A forest fire kills most plant life south of a highway.

Which of the following could increase genetic variation?

 

mutation

If the average tail size of a reptile continually got smaller through generations, this would be an example of

 

directional selection.

All of the genes and all of their associated alleles within a population represent the population's

 

gene pool.

The figure shown here represents stabilizing selection. What happens when an individual is produced that possesses a trait far away from the mean value?

 

That extreme individual likely will not survive and reproduce.

What characteristic is common of both a genetic bottleneck and a founder effect?

Both involve a decrease in a population's genetic diversity.

Why does malaria persist in the human population?

 

Heterozygote advantage maintains both the normal allele and the sickle cell allele in the population.

Analyze the accuracy of the following statement: Dominant alleles are always the most common.

 

This is a false statement because for some genes with two alleles, the recessive allele is more common.

The conditions required by the Hardy-Weinberg equilibrium

 

are rare in nature.

The increase in frequency of dark phenotypes in response to increased pollution is called

 

industrial melanism.

Microevolution is influenced by all of the following except?

 

random mating

In random mating

 

there is no factor influencing mate choice.

Biotic factors that influence natural selection include all but which of the following?

 weather

In the process of natural selection, individuals that are most fit are the ones that

reproduce the most.