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DNA, RNA, and PROTEINS
Chapter 12
REPLICATION- (DNA
→ DNA)
Process by which a cell copies its DNA
→
TRANSCRIPTION- (DNA
RNA)
Process in which a sequence of DNA is copied into a complementary RNA sequence
→
TRANSLATION (RNA
PROTEIN)
Process of decoding an mRNA message into a polypeptide (protein) chain
TRANSFORMATION- Process in which one strain of bacteria is changed by absorbing
DNA from another strain of bacteria
BACTERIOPHAGE – A virus that infects bacteria
CHROMATIN – DNA and proteins that is found SPREAD OUT in the nucleus of
NON-DIVIDING cells
CHROMOSOMES- DNA and proteins tightly coiled around histones that is found
CONDENSED into bundles in DIVIDING cells
HISTONE – protein molecule around which DNA is wrapped to form a nucleosome in
chromatin
NUCLEOSOME – Beadlike structure formed by coiling DNA around histone proteins that
pack together to form chromosomes
NUCLEOTIDE – subunit (monomer) consisting of a 5 carbon sugar, a phosphate group,
and a nitrogen base used to build nucleic acids such as DNA and RNA
DNA POLYMERASE – enzyme involved in DNA replication which joins nucleotide subunits
together to make a DNA molecule
RNA POLYMERASE – enzyme involved in RNA transcription that binds to DNA,
separates the strands, and assembles nucleotide subunits into an RNA molecule
RIBOSOMAL RNA (r-RNA) – type of RNA that combines with proteins to form
ribosomes
MESSENGER RNA (m-RNA) – type of RNA that carries copies of instructions for
making proteins from DNA to the rest of the cell
TRANSFER RNA (t-RNA) – type of RNA that transfers amino acids to the ribosomes
during protein synthesis
CODON –
three-nucleotide sequence on messenger RNA that codes for a single amino acid
ANTICODON – group of three nucleotide bases on a t-RNA molecule that are
complementary to an mRNA codon
OPERON – a group of genes operating together
INTRON – sequence of DNA that is NOT involved in coding for a protein which is cut
out of the m-RNA molecule before it is read by the ribosomes
EXON – Expressed sequence of DNA that codes for a protein
REPRESSOR – molecule that binds to the operator region of an operon and “turns the
gene off”
OPERATOR – region in an operon to which the repressor protein binds when the operon
is “turned off”
PROMOTER – region in an operon to which RNA polymerase binds to begin transcription
HOX GENES – series of genes that control differentiation of cells and tissues in an
embryo
DIFFERENTIATION- the process by which cells change to become specialized in
structure and function
CHROMOSOMAL MUTATION- This type of mutation involves changes in the number or
structure of chromosomes. Such mutation may change the location of genes on
chromosomes, and may even change the number of copies of some genes.
FRAMESHIFT MUTATION-This type of mutation may change every amino acid that
follows the point of mutation. They can alter a protein so much that it is unable to
perform its normal function.
POINT MUTATION- A gene mutation results from changes in a single gene.
POLYPLOIDY- the condition in which an organism has extra sets of chromosomes.
Plants are often larger and stronger than diploid plants.
ENHANCER REGION- In eukaryotes, this is upstream from promoters; it binds many
different regulatory proteins
TATA BOX- In eukaryotes, this helps position RNA polymerase
DNA- double stranded nucleic acid; deoxyribose sugar; contains nitrogen bases of
adenine, guanine, cytosine, and thymine
RNA- single stranded nucleic acid; ribose sugar; contains nitrogen bases of adenine,
guanine, cytosine, and uracil
PURINES- Nitrogen bases with 2 rings; Adenine & Guanine
PYRIMIDINES- Nitrogen bases with 1 ring; Cytosine & Thymine
CHARGAFF’S RULE- Adenine always codes to Thymine; Guanine always codes to Cytosine
REPLICATION FORK- Sites where DNA strand separation occur