Chapter 11: Biotechnology

Question 1

What is recombinant DNA (rDNA)?

Answer 1

DNA altered to contain nucleotides from two different organisms.

Question 2

What is a genetically modified organism (GMO)?

Answer 2

An organism expressing a new gene introduced through genetic modification.

Question 3

What is the most commonly used bacterium in genetic engineering?

Answer 3

Escherichia coli (E. coli).

Question 4

What are the general steps of gene transfer?

Answer 4

Identify the gene → Amplify via PCR → Insert into vector → Transfer to cells → Identify & clone modified cells.

Question 5

What are common vectors used in gene transfer?

Answer 5

Plasmids, viruses, and liposomes.

Question 6

What are the main enzymes used in gene transfer?

Answer 6

Restriction endonucleases, ligase, and reverse transcriptase.

Question 7

What do restriction endonucleases do?

Answer 7

Cut DNA at specific sequences.

Question 8

What is the function of DNA ligase in genetic engineering?

Answer 8

Joins DNA fragments by linking their sticky ends.

Question 9

Where is most of E. coli’s genetic information stored?

Answer 9

In a single chromosome.

Question 10

What is a plasmid?

Answer 10

A small, circular DNA molecule separate from the bacterial chromosome.

Question 11

Why are plasmids important in cloning?

Answer 11

They act as vectors to transfer foreign genes into bacteria.

Question 12

What is a recombinant plasmid?

Answer 12

A plasmid containing an inserted foreign gene.

Question 13

Which enzyme is used to convert mRNA into DNA?

Answer 13

Reverse transcriptase.

Question 14

What is the role of DNA polymerase in insulin production?

Answer 14

Converts single-stranded DNA to double-stranded DNA.

Question 15

What are transgenic plants?

Answer 15

Plants with introduced foreign genes for desirable traits.

Question 16

What is an example of transgenic animal use in medicine?

Answer 16

Transgenic sheep producing factor IX for hemophilia treatment.

Question 17

What technique is used to separate molecules like proteins and DNA?

Answer 17

Gel electrophoresis.

Question 18

What factors affect molecule movement in gel electrophoresis?

Answer 18

Net charge, size, and gel composition.

Question 19

Why do DNA fragments move in electrophoresis?

Answer 19

Due to their negatively charged phosphate groups.

Question 20

What is DNA profiling?

Answer 20

Matching an unknown DNA sample to a known one.

Question 21

What is PCR used for?

Answer 21

Rapidly producing a large number of DNA copies.

Question 22

What are the three main steps of PCR?

Answer 22

Denaturation, annealing, and extension.

Question 23

What is the purpose of a primer in PCR?

Answer 23

It starts DNA synthesis.

Question 24

What is gene sequencing?

Answer 24

Identifying all bases in an organism’s genome.

Question 25

Which technique is commonly used for gene sequencing?

Answer 25

Sanger sequencing.

Question 26

What does the Sanger technique involve?

Answer 26

Fragmenting DNA, copying fragments, and reading base sequences.

Question 27

What is a clone?

Answer 27

A group of genetically identical organisms or cells.

Question 28

How can animals be cloned from embryos?

Answer 28

By separating embryonic cells and implanting them into a uterus.

Question 29

How was Dolly the sheep cloned?

Answer 29

Using the nucleus from an adult cell fused with an enucleated egg cell.

Question 30

What was a key finding from Dolly’s cloning?

Answer 30

Differentiated cells can be used to create a clone.

Question 31

What is a microarray?

Answer 31

A tool used to analyze gene expression and genome composition.

Question 32

How do microarrays detect gene expression?

Answer 32

By hybridizing cDNA to DNA probes on a chip.

Question 33

Which enzyme is used to convert mRNA to cDNA in microarrays?

Answer 33

Reverse transcriptase.

Question 34

What is a key application of microarrays?

Answer 34

Comparing gene expression in cancer vs. normal cells.

Question 35

What happens if a DNA sample does not bind to a microarray probe?

Answer 35

The gene is absent in that sample.

Question 36

What does fluorescence in a microarray indicate?

Answer 36

Hybridization of cDNA to a complementary DNA probe.

Question 37

What is the purpose of gel electrophoresis in diagnosing sickle cell anemia?

Answer 37

To separate hemoglobin variants based on charge differences.

Question 38

What is the function of a buffer solution in PCR?

Answer 38

Maintains pH and stabilizes enzymes.

Question 39

Why is PCR useful in forensic science?

Answer 39

It amplifies small DNA samples for analysis.

Question 40

What role does a DNA polymerase play in PCR?

Answer 40

It synthesizes new DNA strands.

Question 41

What kind of charge do proteins typically have in electrophoresis?

Answer 41

A net negative charge.

Question 42

What is the main component of the gel used in electrophoresis?

Answer 42

Agarose.

Question 43

Why do smaller DNA fragments move faster in gel electrophoresis?

Answer 43

They experience less resistance in the gel.

Question 44

What are sticky ends in genetic engineering?

Answer 44

Overhanging sequences left after restriction enzyme cuts.

Question 45

What is an application of DNA profiling?

Answer 45

Paternity testing.

Question 46

What is a practical use of genetically modified crops?

Answer 46

Pest resistance.

Question 47

Why is E. coli commonly used in genetic engineering?

Answer 47

It grows rapidly and its genetics are well understood.

Question 48

How does electrophoresis separate sickle cell hemoglobin from normal hemoglobin?

Answer 48

They have different charges and migrate differently in the gel.

Question 49

What is the first step in cloning a gene?

Answer 49

Identifying and isolating the gene.

Question 50

How does PCR achieve exponential DNA amplification?

Answer 50

Each cycle doubles the number of DNA copies.

Question 51

What happens if a PCR primer does not match the DNA template?

Answer 51

DNA replication will not occur.

Question 52

What is the advantage of using cDNA in microarrays?

Answer 52

It represents actively expressed genes.

Question 53

Why is a fluorescent dye used in microarrays?

Answer 53

To visualize hybridization of DNA samples.

Question 54

Why do restriction enzymes cut at specific sites?

Answer 54

They recognize particular base sequences.

Question 55

How do scientists identify transformed cells in gene transfer?

Answer 55

By using marker genes for selection.

Question 56

What is a key advantage of microarrays?

Answer 56

They allow simultaneous analysis of thousands of genes.

Question 57

What does a microarray measure?

Answer 57

Gene expression levels.

Question 58

What is a DNA probe in a microarray?

Answer 58

A single-stranded DNA sequence that binds complementary sequences.

Question 59

What is a major application of DNA sequencing?

Answer 59

Identifying mutations linked to diseases.

Question 60

What does Sanger sequencing use to terminate DNA synthesis?

Answer 60

Dideoxynucleotides (ddNTPs).

Question 61

What is an alternative to Sanger sequencing for whole-genome sequencing?

Answer 61

Next-generation sequencing (NGS).

Question 62

Why is DNA sequencing important in medicine?

Answer 62

It helps diagnose genetic disorders.

Question 63

What are the steps of cloning an organism?

Answer 63

Isolate DNA → Insert into vector → Introduce to host → Select clones.

Question 64

What is a common method for inserting DNA into bacterial cells?

Answer 64

Transformation using plasmids.

Question 65

What ethical concerns exist around human cloning?

Answer 65

Issues of identity, consent, and genetic modification.

Question 66

Why is cDNA used instead of mRNA in microarrays?

Answer 66

cDNA is more stable and easier to analyze.

Question 67

What role do fluorescent tags play in DNA sequencing?

Answer 67

They label bases to identify the sequence.

Question 68

What is one use of cloned animals in research?

Answer 68

Studying genetic diseases.

Question 69

Why is gel electrophoresis used before sequencing?

Answer 69

To check the quality and size of DNA fragments.