36 terms

Chapter 17 Review for Biology 621

A review of the key terms from Chapter 17.
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dna
deoxyribonucleic acid; the unique genetic code for every living thing.
Watson and Crick
Scientists who proposed the double helix structure of DNA
adenine
The base that pairs with Thymine in DNA
thymine
The base that pairs Adenine in DNA
cytosine
The base that pairs with Guanine with DNA
guanine
The base that pairs with Cytosine in DNA
Thomas Morgan
Documented sex-linked traits in fruit flies
replication
The process by which a cell makes a copy of the DNA in its nucleus
Deoxyribose
A five-carbon sugar found in DNA.
Phosphate group
alternates with deoxyribose to make up the sides of DNA
Griffith
used mice to discover that genetic material had a transforming factor,
Hershey and Chase
Identified DNA to be genetic material through experiments with bacteriophages
Initiation
DNA replication is initiated when helicase enzyme breaks the hydrogen bonds holding the base pairs together and the DNA uncoils.
Elongation
Addition of nucleotides on uncoiled DNA through polymerase.
Ligase
The enzyme that joins DNA fragments together
RNA
Ribonucleic acid; a nucleic acid that plays an important role in the production of proteins
Protein synthesis
The assembly of chains of amino acids into functional protein molecules
Uracil
a nitrogen-containing base found in RNA (but not in DNA)
mRNA
Messenger RNA; the RNA molecule that serves as the template for protein synthesis.
tRNA
Transfer RNA; the type of RNA that carries an amino acid from the cytoplasm to the ribosome for incorporation into a growing protein.
rRNA
Ribosomal RNA; the type of RNA that associates with ribosomal proteins to make a functional ribosome.
Transcription
A process in which DNA is used as a template to make complementary messenger RNA.
Translation
The assembly of a protein on a ribosome, using mRNA to direct the order in wich amino acids are added to the protein being made.
AUG
Start codon for protein synthesis.
ribosome
A cell organelle which functions as the site of protein synthesis in the cytoplasm; consists of rRNA and protein molecules, which make up two subunits.
exons
coding regions; parts of a gene that are expressed as amino acids
introns
sequences of nucleotides not involved in coding for proteins
oncogenes
genes that cause cancer by blocking the normal controls on cell reproduction
structural genes
a DNA sequence that codes for a specific product
repressor protein
a regulatory protein that binds to an operator and blocks transcription of the genes of an operon
operator gene
controls the activity of the structured genes (switches on/off to control transcription)
mutations
change in the nucleotide sequence of DNA
Substitution Mutation
A single nucleotide is replaced by a different nucleotide
missense mutation
a type of point mutation that results in an alternate incorrect amino acid to be coded; produces a disfunctional protein
nonsense mutation
a mutation that changes an amino acid codon to one of the 3 stop codons, resulting in a shorter and usually nonfunctional protein
silent mutation
a type of point mutation in which no harmful effect is produced