Exam 3 - Terms Flashcards
What are nucleotides?
The building block of DNA and RNA.
What are the 3 parts of a nucleotide?
a base, a phosphate, and a sugar
What a hydrogen bond?
A weak chemical bonding force between hydrogen and another atom
What is a covalent bond?
Chemical bonds that result from electron sharing between atoms. Covalent bonds are formed and broken during chemical reactions
What is the difference between a covalent bond and a hydrogen bond?
Covalent bonds are stronger and share electrons during chemical reactions. Hydrogen bonds are weak and bond hydrogen with other atoms
What is Pre-mRNA?
The transcript made from the DNA template that is processed and modified to form messenger RNA
What is mRNA?
A single stranded complementary copy of the amino acid coding nucleotide sequence of a gene
What is rRNA?
RNA molecules that form part of the ribosome
What are ribosomes?
Cytoplasmic particles that aid in the production of proteins
What is tRNA?
Connects mRNA to the peptide chain with anticodons
What is an intron?
DNA sequences present in some genes that are transcribed but are removed during processing and therefore not present in mature mRNA
What is an exon?
DNA sequences that are transcribed, joined to other exons, and translated into amino acid sequence of a proton
What is a base?
A substance whose molecule or ion can combine with a proton, and is capable of donating a pair of electrons (to an acid) to form a covalent bond
What is a base pair?
The two complementary, nitrogen rich molecules held together by weak chemical bonds. Two strands of DNA are held together in the shape of double helix by the bonds between their base pairs
What is an enzyme?
A protein that speeds up chemical reactions in the body
What is the “-ase” suffix used for?
It is used to form names in enzymes
What is a peptide bond?
A covalent chemical link between the carboxyl group of one amino acid and the amino group of another amino acid
What is the N-terminus?
The end of a polypeptide or protein that has a free amino group
What is the C-terminus?
The end of a polypeptide or protein that has a free carboxyl group
What is the 5’ flanking region?
The region of DNA which borders the 3’ end of a transcription unit and where a variety of regulatory sequences are located
What is the 3’ flanking region?
The region of DNA which borders the 3’ end of a transcription unit and where a variety of regulatory sequences are located
What is a codon?
Triplets of nucleotides in mRNA that encode the information for a specific amino acid in a protein
What is an anticodon?
A group of 3 nucleotides in a tRNA molecule that pairs with a complementary sequence (codon) in a mRNA molecule
What is the promoter?
A region of DNA molecule to which RNA polymerase binds and initiates transcription
What is transcription?
Transfer of genetic information from the base sequence of DNA to the base sequence of RNA, mediated by RNA synthesis
What is translation?
Conversion of information encoded in the nucleotide sequence of an mRNA molecule into the linear sequence of amino acids in a protein
What is the template strand?
The single stranded DNA that serves to specify the nucleotide sequence of a newly synthesized polynucleotide strand
What is a substrate?
The specific chemical compound that is acted on by an enzyme
What is a product?
The specific chemical compound that is the result of an enzymatic action. In biochemical pathways, a compound can serve as the product of one reaction and the substrate for the next reaction
What is a metabolic pathway?
Any of the sequences of biochemical reactions catalyzed by enzymes that occur in all living cells
What is an essential amino acid?
Amino acids that cannot be synthesized in the body and must be supplied in the diet
What is achondroplasia?
A form of dwarfism, normal intelligence, problem is converting cartilage to bone
What is a mutagen?
A agent, such as radiation or a chemical substance, that caused genetic mutation
What is ionizing radiation?
Radiation that produces ions during interaction with other matter, including molecules in cells
What is nucleotide substitution?
Mutations that involve replacement of one or more nucleotides in a DNA molecule with other nucleotides
What is a thymine dimer?
A molecular lesion in which chemical bonds form between a pair of adjacent thymine bases in a DNA molecule
What is xeroderma pigmentosum?
Extreme sensitivity to UV rays
What is a missense mutation?
Mutations that cause the substitution of one amino acid for another in a protein
What is a nonsense mutation?
Mutations that change an amino acid specifying a codon to one of the three termination codons
What is a neutral mutation?
A mutation that has no selective advantage or disadvantage
What is a benign tumor?
A tumor that lacks the ability to invade neighboring tissue
What is cancer?
The disease caused by an uncontrolled division of abnormal cells in a part of the body
What is metastasis?
A process by which cells detach from the primary tumor and move to other sites, forming new malignant tumors in the body
What are somatic mutations?
A change in the genetic structure that is neither inherited nor passed to offspring
What is apoptosis?
A cell self destructs and leaves no trace it was ever there
