Biology Ch. 14

Viral DNA makes mRNA by the process of _____.

transcription

Which of the following is most similar to a DNA probe?

a PCR primer

The pointer is indicating the virus's _____.

genome

Which of the following is an example of biotechnology?

using bacteria to convert milk into yogurt

What enzyme forms covalent bonds between restriction fragments?

DNA ligase

You have just discovered a new gene in humans called FAKE. There are two alleles for FAKE. Allele 1 contains three EcoRI restriction sites, and allele 2 contains four (as shown). You perform a restriction digest using Allele 2, run the sample on a gel, and probe using a piece of DNA that spans this extra restriction site. Which sample on the gel shown belongs to Allele 2?

sample C

The unpaired nucleotides produced by the action of restriction enzymes are referred to as _____.

sticky ends

It has been proposed that new crops produced using genetic marker biotechnology may appeal to consumers who wish to avoid genetically modified foods. Consider the process of marker-assisted breeding relative to genetic engineering for producing new crop strains. Sort each characteristic or example to the technology it applies to.

(see following terms)

The sticky end of the DNA restriction fragment shown here will pair with a DNA restriction fragment with the sticky end _____.

-ACGT

Marker-assisted breeding

1) Limited to traits already present in the existing crop 2) Uses traditional breeding techniques to produce crops with preferred properties

Marker-assisted breeding has many potential advantages over conventional breeding. What are they? Select all that apply.

1) Plants can be screened earlier in development. 2) Breeders can avoid the plants that did not inherit the selected traits. 3) Plants can be screened for the presence of desirable traits more rapidly.

DNA fragment B consists of _____ base pairs.

1,405

Finally, how can you use your assessment of the authority, motivation, and reliability of the information to evaluate this web site relative to other sources? Use the scales below to assign a numerical score to this source.

2 to 4

Not all GMO crops include transgenic methods. Which of the following mechanisms allow researchers to change, silence, or enhance a gene without introducing foreign DNA to a plant cell?

CRISPR-Cas9

Which of these DNA molecules is the shortest?

E

After accounting for all the side effects associated with transgenic organisms, specifically food-based organisms, what has the National Academy of Sciences recommended regarding their use?

No serious side effects have been identified with regard to human consumption of genetically altered foods.

How can you know if the information is based on scientifically collected data and if it's corroborated by other sources? Look more closely around the web page. Click the "serious risks" link in the fourth paragraph; then click the "scientific review" link in the sixth paragraph. What do you find when you click these two links?

One links to another page on the CFS web site, and one links to a paper in a peer-reviewed journal.

How does a plasmid compare to the bacterial chromosome?

Plasmids are smaller than the bacterial chromosome.

The gel below contains the results of analysis of two different STRs. What can you conclude for certain?

Samples B and D came from two different people.

At which STR locus or loci is the child homozygous? Select all that apply.

TPOX D18S

When performing a diagnostic array for cystic fibrosis, how can you determine if an individual is a heterozygous carrier for the disease?

The individual's sample will show a positive result for the normal allele and a positive result for the CFTR allele.

What event is necessary for a virus to move genes from one organism to another?

The virus must insert its DNA into the genome of the host, where it becomes incorporated and replicated by the host cell as it prepares for cell division.

Why is it more difficult to test for cystic fibrosis than to test for sickle-cell anemia?

There are many more disease alleles for cystic fibrosis than for sickle-cell anemia.

In order to select the markers that would be useful in developing larger, flavorful, and durable cantaloupes, researchers had to perform genetic tests on both types of cantaloupe: the tasty and durable (but tiny) cantaloupes and the large but bland conventional cantaloupes. Why was this necessary?

They needed to establish which markers were associated with which traits.

How do scientists generate large amounts of a particular piece of DNA they wish to work with?

They use DNA cloning, which inserts a desired gene into a bacterial plasmid.

Why do scientists make plants and farm animals that are transgenic for human antibodies and hormones?

This is a way to produce large amounts of these products cheaply.

What is the current status of transgenic food products in the United States?

Transgenic food is commonly found in the grocery store.

In order to insert a human gene into a plasmid, both must _____

be cut by the same restriction enzyme

Which of the following have humans accomplished only by modern biotechnology?

create new alleles

In a PCR reaction, the strands of DNA are first separated by ___.

heating

The gel below shows the results of STR analysis for four individuals. Which one is heterozygous for the STR?

individual D

Genes in the human genome sequence can be identified in all of the following ways EXCEPT

matching genome sequences to proteins.

In gel electrophoresis DNA molecules migrate from _____ to _____ ends of the gel.

negative ... positive

Which technique can be used to determine if a patient carries a disease allele no matter which gene you may be trying to analyze?

probe array

What is the correct sequence of events that occur in a PCR reaction?

separation of DNA strands; addition of primers; use of DNA polymerase to produce second strand of DNA

DNA polymerase is a heat-sensitive enzyme. What is one thing that would need to be considered concerning the activity of this enzyme in PCR when the temperature is heated during each cycle to separate the DNA strands?

that the primers might not work that the DNA polymerase could be denatured

What information would a scientist need first to analyze several samples for one STR locus?

the sequence of the DNA on either side of the repeat

Next, can you identify what the source is trying to accomplish by providing this information? As you read the post, think about what the writer's agenda might be with regard to GMOs. What seems to be the main purpose of the blog post?

to convince the public that genetic engineering is not the solution to citrus greening

Starting with just one copy of the target gene, how much DNA will be present after 30 rounds of PCR?

1 billion copies

Genetic engineering

1) Can produce a strain of cantaloupe that resists bruising by introducing genes from apples 2) Can increase insect resistance in crops by giving them the Bt gene from a bacterium

Both

1) Involves biotechnological tools 2) Produces improved crop varieties more rapidly than conventional breeding

What conclusion(s) can be drawn from the STR data in this paternity testing case? Select all that apply.

1) The child must have inherited the 12 repeats at locus D5S from Man 2, based on data from that locus alone. 2) The child could have inherited the 11 repeats at locus D13S from either Man 1 or Man 2, based on data from that locus alone. 3) Man 2 is likely the father of the child, based on the data from all six loci.

Can you match these biology terms with their definitions? Drag the terms on the left to the appropriate blanks on the right to complete the sentences.

1. Biotechnology is the use or alteration of organisms, cells, or biological molecules to produce food, drugs, or other goods. 2. A transgenic organism expresses DNA that has been derived from another species. 3. In a process known as transformation, bacteria take up pieces of DNA from their surroundings. 4. Polymerase chain reaction is a technique used to quickly synthesize billions of copies of a specific segment of DNA. 5. DNA that has been altered to contain genes, or portions of genes, from different organisms is known as recombinant DNA. 6. A restriction enzyme, which is found naturally in bacteria, cuts DNA at a specific nucleotide sequence.

Open the site in your browser and skim the article. Think about whether you believe the information presented or whether you have doubts about some of it. On a scale of 0 to 6, where 6 is the most trustworthy, how would you rate this site? (Note that all responses will be marked as "correct" at this point.)

5-6 (very trustworthy)

In this example the marker DNA includes fragments that have 23,130, 9,416, 6,557, 4,361, 2,322, 2,027, and 564 base pairs. Approximately how many base pairs are in the DNA fragment indicated by the letter A?

6,557

Why are chromosomes cut into fragments for sequencing?

A DNA sequencing reaction can only accurately determine about 500 bases of DNA.

Which of the following is most similar to the process of creating a plant that expresses Bt toxins to ward off insects?

A strain of bacteria transfers an antibiotic-resistance plasmid to another strain of bacteria.

Which of the following sentences correctly makes use of terms related to biotechnology?

Genetic engineering can move genes from one species into another, creating a transgenic organism.

What is the major difference between the strategies of map-based sequencing and shotgun sequencing?

In shotgun sequencing, DNA fragments are sequenced before their correct order is known.

How do STR alleles differ from one person to the next?

It differs in the number of times the sequence is repeated.

On the whole, how has biotechnology been used most successfully by humans?

It has been most successful at creating transgenic organisms to manufacture products for us.

How does gel electrophoresis help when analyzing samples of DNA?

It separates DNA fragments by length.

Fusarium wilt is a fungal disease that damages melon crops. Suppose you have been asked to evaluate the data gathered by a team of researchers seeking to use marker-assisted breeding to select for Fusarium-wilt resistance in melons. [...] Based on the data, which markers should the researchers rely on for screening melon seeds for resistance to Fusarium wilt? Select all that apply.

Marker C Marker D

Now, search for information on GMOs on at least two other web sites, including the United States Department of Agriculture (USDA.gov) and the World Health Organization (WHO.int). Is the information provided by these sites consistent with what you found on the CFS web site?

Other sites discuss both the risks and benefits associated with GMOs.

What is the method used in biotechnology that mass-copies DNA, using cyclic temperature regimens and a heat-tolerant enzyme?

PCR

Which of the following is a major difference between PCR and replication of DNA during the cell cycle?

PCR copies only a specific portion of DNA. Replication copies the entire genome.

CRISPR-Cas9 is a tool that has become important in many biotechnology applications. What component of the tool allows it to recognize a specific gene target?

RNA guide sequence

Consider a collection of hypothetical results regarding cantaloupes grown from seeds with various combinations of markers. In which of the scenarios does it appear that the markers present in the seeds are good predictors of melon phenotypes? Select all that apply.

Scenario 1 Scenario 4 Scenario 5

How can you know if the person or organization providing the information has the credentials and knowledge to speak on this topic? One clue is the type of web site it is--the domain name ".org" tells you that this site is run by a nonprofit organization. Now scan the post to find the name and credentials of the person who wrote it. What is the affiliation of the writer?

She is on staff at the Center for Food Safety (CFS).

How are genes inserted into plasmids?

The DNA gene and plasmid are cut with the same restriction enzyme; the desired gene has complementary sticky ends with the bacterial plasmid that readily base-pairs into the plasmid.

Imagine that you are a technician in a forensics lab. You need to analyze different STRs in a sample. Being trained in this protocol, you set out first to amplify the STR DNA sample and you set up the PCR. This technique uses primers that contain dye molecules to distinguish different sizes of STRs. In this investigation, you are interested in analyzing two different STRs. You load these primed and amplified STRs onto a gel. How can you identify each of the different STRs?

The dyes incorporated into the primers used for each STR are a different color that is read by an STR analyzer machine.

How does the definition of "transformation" apply to natural processes discovered about prokaryotic genetics?

Transformation is any time bacteria pick up and incorporate fragments of DNA from the environment or interact with other organisms, including other bacteria.

When is PCR particularly applicable?

When there are small quantities of DNA to analyze

A BAC library is

a collection of human DNA fragments carried on chromosomes in bacterial cells.

In this example the marker DNA includes fragments that have 23,130, 9,416, 6,557, 4,361, 2,322, 2,027, and 564 base pairs. Approximately how many base pairs are in the DNA fragment indicated by the letter B?

between 6,557 and 4,361 base pairs

Which of the following would be the first step in creating a transgenic cure for cystic fibrosis?

cloning the healthy CFTR allele