ASSORTMENT of all S2 units

DNA & Central Dogma, Genetics, Biotech, Evolution, and Climate Change

What is a nucleotide?

a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.

What is a nitrogen base?

A molecule that forms the rungs of the DNA ladder.

What is sugar?

A component of nucleotides in DNA and RNA.

What is a phosphate group?

a molecule in the backbone of DNA and RNA that links adjoining bases together. A phosphorus atom bonded to four oxygen atoms

What is deoxyribose?

-Pentose sugar found in DNA nucleotides

What is ribose?

the sugar found in RNA nucleotides

What is adenine?

A nitrogen base that pairs with thymine in DNA.

What is thymine?

A nitrogen base that pairs with adenine in DNA.

What is cytosine?

A nitrogen base that pairs with guanine in DNA.

What is guanine?

A nitrogen base that pairs with cytosine in DNA.

What is a hydrogen bond?

A weak "bond" that holds nitrogen bases together in DNA.

What is a covalent bond?

A chemical bond formed when two or atoms share electrons. A strong bond that holds nucleotides together in DNA.

What is antiparallel?

The opposite orientation of the two strands in DNA.

What are 5' and 3' ends?

The two ends of a DNA strand that refer to the carbon number in the sugar.

What is a pyrimidine?

A nitrogen base with a single ring structure, such as thymine and cytosine.

What is a purine?

A nitrogen base with a double ring structure, such as adenine and guanine.

What is RNA?

ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information.

What is DNA?

deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.

What is a strand?

A single chain of nucleotides in DNA or RNA.

What is replication?

The process of copying DNA.

What is semiconservative?

The mechanism of DNA replication where each new strand contains one original and one new strand.

What is a template strand?

The strand of DNA that is used as a template for RNA synthesis.

What is DNA polymerase I?

An enzyme that removes RNA primers and replaces them with DNA nucleotides during DNA replication.

What is DNA polymerase III?

An enzyme that adds nucleotides to the growing DNA strand during DNA replication.

What is ligase?

An enzyme that joins Okazaki fragments during DNA replication.

What is helicase?

An enzyme that unwinds DNA during DNA replication.

What is primase?

An enzyme that synthesizes RNA primers during DNA replication.

What is the leading strand?

The strand of DNA that is synthesized continuously during DNA replication.

What is the lagging strand?

The strand of DNA that is synthesized in short fragments during DNA replication.

What are Okazaki fragments?

Short fragments of DNA that are synthesized on the lagging strand during DNA replication.

What is a replication fork?

The point where DNA strands separate during DNA replication.

What is SSB?

A protein that binds to single-stranded DNA to prevent it from re-forming a double helix during DNA replication.

What is topoisomerase?

An enzyme that relieves the tension caused by unwinding DNA during DNA replication.

What is pre-mRNA?

The initial RNA transcript before it is modified into mature mRNA.

What is tRNA?

A type of RNA that carries amino acids to the ribosome during translation.

What is rRNA?

A type of RNA that forms part of the ribosome.

What is transcription?

The process of synthesizing RNA from DNA.

What is translation?

The process of synthesizing a protein from mRNA.

What is DNA modification?

The process of adding chemical modifications to DNA that can affect gene expression.

What is RNA polymerase?

An enzyme that synthesizes RNA during transcription.

What is a promoter?

A region of DNA that signals the start of a gene and the site of RNA polymerase binding.

What is splicing?

The process of removing introns and joining exons in pre-mRNA.

What is a 5' cap?

A modified guanine nucleotide added to the 5' end of mRNA. Helps the mRNA leave through the nuclear pore.

What is a poly-A tail?

A string of adenine nucleotides added to the 3' end of mRNA. Helps prevent degradation when in the cytoplasm

What is an exon?

A coding region of DNA that is expressed in the final mRNA.

What is an intron?

A non-coding region of DNA that is removed during splicing.

What is initiation?

The first stage of translation where the ribosome assembles around the mRNA.

What is elongation?

The second stage of translation where the polypeptide chain grows.

What is termination?

The final stage of translation where the ribosome releases the polypeptide chain.

What are A, P, and E sites?

The three binding sites for tRNA on the ribosome.

What is a codon?

A sequence of three nucleotides that codes for an amino acid.

What is an anticodon?

A sequence of three nucleotides on tRNA that binds to a complementary codon on mRNA.

What is a reading frame?

The way in which a sequence of nucleotides is read in groups of three to determine the amino acid sequence.

What are amino acids?

The building blocks of proteins.

What is a protein?

A large, complex molecule made up of amino acids.

What is a polypeptide?

A chain of amino acids linked by peptide bonds.

What is a ribosome?

A complex of RNA and protein that synthesizes proteins.

What is the nucleus?

The organelle in eukaryotic cells that contains DNA.

What is mRNA?

A type of RNA that carries genetic information from DNA to the ribosome.

What is uracil?

A nitrogen base that pairs with adenine in RNA.

What is a mutation?

A change in the DNA sequence.

What is a missense mutation?

A mutation that changes one amino acid in a protein.

What is a nonsense mutation?

A mutation that creates a premature stop codon in a protein.

What is a frameshift mutation?

A mutation that shifts the reading frame of a gene.

What is an insertion?

A mutation that adds one or more nucleotides to a gene.

What is a silent mutation?

A mutation that does not change the amino acid sequence of a protein.

What is a deletion?

A mutation that removes one or more nucleotides from a gene.

What is a substitution/point mutation?

A mutation that replaces one nucleotide with another.

What is the A site of a ribosome?

The site where each new tRNA delivers its amino acid.

What is the P site of a ribosome?

Where a new peptide bond forms. Where the growing polypeptide still atached to tRNA is located during translation.

What is the E site of a ribosome?

the exit site, where discharged tRNAs leave the ribosome

What is a plasmid?

Small, circular DNA molecule in bacteria.

What is recombinant DNA?

DNA formed by combining DNA from different sources.

What are bacteria?

Single-celled microorganisms.

What is an antibiotic?

A medicine that inhibits bacterial growth.

What is antibiotic resistance?

the ability of a microorganism to withstand the effects of an antibiotic

What is a restriction enzyme?

Enzyme that cuts DNA at specific sequences.

What is biotechnology?

the use of microorganisms, cells, or cell components to make a product

What is genetic engineering?

Manipulation of DNA to change an organism's traits.

What is DNA?

Molecule that carries genetic information.

What is agarose gel?

Gel used to separate DNA fragments by size.

What is gel electrophoresis?

Technique used to separate DNA fragments by size.

What is electrophoresis buffer?

Solution used to conduct electricity in gel electrophoresis.

What is the negative electrode?

Negative end of the gel electrophoresis. When running DNA, the wells of the gel should be closest to this side.

What is the positive electrode?

Positive end of the gel electrophoresis. DNA travels toward this end.

What is a well?

Indentation in the gel where DNA samples are loaded.

What is a lane?

Channel in the gel where DNA fragments migrate.

What are blunt ends?

Ends of DNA fragments cut straight across by restriction enzymes.

What are sticky ends?

Ends of DNA fragments cut with staggered ends by restriction enzymes.

What is the origin of replication?

Site where DNA replication begins.

What is a resistance gene?

Gene that confers antibiotic resistance.

What is an activator protein gene?

Gene that codes for a protein that activates transcription.

What is a promoter?

Region of DNA that initiates transcription.

What is a target gene?

Gene that is regulated by an activator protein.

What is ligase?

Enzyme that joins DNA fragments together.

What is the sugar phosphate backbone?

Alternating chain of sugar and phosphate molecules in DNA.

What is cDNA?

DNA synthesized from RNA by reverse transcriptase.

What is reverse transcriptase?

Enzyme that synthesizes DNA from RNA.

What is bacterial transformation?

Process of introducing foreign DNA into bacteria.

What is a petri dish?

Shallow dish used to culture bacteria.