Separating charged molecules such as DNA fragments by size, as an electric current pulls them through a gel, is called electrophoresis.
Missing Word
electrophoresis
Electrophoresis sorts nucleic acid fragments by size because smaller pieces move through the gel's pores faster. The fragments are then stained so their bands can be seen.
Category: Lab Techniques
Question 2
Transgenic goats and sheep have been engineered to secrete certain human proteins in their milk.
Missing Word
milk
Some medical proteins need a eukaryotic host to be processed correctly, so their genes are placed in goats or sheep that release the protein in their milk. One anticoagulant protein made this way in goat milk has been approved for human use.
Category: Medical Biotechnology
Question 3
Spinning a sample at high speed so that cell debris collects at the bottom of the tube is called centrifugation.
Missing Word
centrifugation
Centrifugation uses rapid spinning to separate materials by density, packing debris into a pellet. In DNA extraction, the liquid above the pellet, which holds the DNA, is kept.
Category: Lab Techniques
Question 4
A small, circular DNA molecule that copies itself independently of the bacterial chromosome is called a plasmid.
Missing Word
plasmid
Plasmids are extra DNA circles found in bacteria. Because they can carry inserted foreign genes into a host cell and be copied there, they are the most common carriers used in molecular cloning.
Category: Molecular Cloning
Question 5
Any DNA carrier, such as a modified virus, that moves a chosen gene into a host cell is called a vector.
Missing Word
vector
A vector delivers foreign DNA into a cell. Plasmids serve as vectors in bacteria, and modified viruses serve as vectors in gene therapy.
Category: Molecular Cloning
Question 6
An organism that is genetically identical to the individual that donated its nucleus is called a clone.
Missing Word
clone
A clone carries the same DNA as its donor. Reproductive cloning produces one by placing a donor body cell's nucleus into an egg cell whose own nucleus has been removed.
Category: Cloning and Transgenics
Question 7
In reproductive cloning, the early embryo is implanted into a surrogate mother, who carries it to birth.
Missing Word
surrogate
The surrogate mother provides the uterus in which the cloned embryo develops. She contributes no genes to the offspring.
Category: Cloning and Transgenics
Question 8
The first mammal cloned from an adult body cell, a sheep born in 1996, was named Dolly.
Missing Word
Dolly
Dolly was cloned from a mammary cell of an adult sheep. Her birth showed that the nucleus of a specialized adult cell could direct the development of a whole new animal.
Category: Cloning and Transgenics
Question 9
Preparations that train the immune system to protect against a disease, made traditionally from weakened or inactivated microbes, are called vaccines.
Missing Word
vaccines
Vaccines prime the immune system to recognize a pathogen. Biotechnology now makes some vaccines by cloning a pathogen's genes and mass-producing the proteins in bacteria.
Category: Medical Biotechnology
Question 10
The field that studies an organism's complete set of DNA, including all its genes and how they interact, is called genomics.
Missing Word
genomics
Genomics examines entire genomes rather than single genes. It became possible once DNA sequencing technology could read large amounts of DNA quickly.
Category: Genomics and Proteomics
Question 11
Determining the exact order of nucleotides in a stretch of DNA is called sequencing.
Missing Word
sequencing
Sequencing reads the order of A, T, G and C bases. Whole-genome sequencing applies it to an organism's entire DNA.
Category: Genomics and Proteomics
Question 12
Recombinant bacteria are used to produce human insulin, the hormone given to people with diabetes.
Missing Word
insulin
Insulin is the hormone that lowers blood glucose, and people with type 1 diabetes must replace it. Bacteria carrying the cloned human insulin gene can make it in large amounts, and the human form avoids the allergic reactions that insulin from pigs caused in some patients.
Category: Medical Biotechnology
Question 13
Most microbes in nature live together in mixed, surface-attached communities called biofilms.
Missing Word
biofilms
Biofilms are communities of microbes stuck to a surface. Because so many microbes live this way and resist growing alone, metagenomics studies their DNA directly from environmental samples.
Category: Genomics and Proteomics
Question 14
The study of the entire set of polypeptides made by a cell type and how they function is called proteomics.
Missing Word
proteomics
Proteomics complements genomics by looking at the products genes actually make. Because the set of proteins changes with conditions, it reveals activity that the genome alone cannot.
Category: Genomics and Proteomics
Question 15
A single protein whose level in body fluids changes with a disease and can be used to screen for it is called a biomarker.
Missing Word
biomarker
A biomarker is one protein used as a sign of disease, such as PSA for prostate cancer. A set of proteins used the same way is called a protein signature.
Category: Genomics and Proteomics