bio120 ch12

Adenine

One of four nitrogen-containing bases in nucleotides composing the structure of DNA and RNA. Pairs with thymine

Guanine

One of four nitrogen containing bases in nucleotides composing the structure of DNA and RNA. Pairs with cytosine

Thymine

One of four nitrogen containing bases in nucleotides composing the structure of DNA and RNA. Pairs with adenine

Cytosine

One of four nitrogen containing bases in nucleotides composing the structure of DNA and RNA. pairs with guanine

double helix

Double spiral

complementary base pairing

A bonds with T, C bonds with G

DNA replication

The process of copying a DNA molecule

template

A mold used to produce a shape complementary to itself

semiconservative replication

A term for DNA Replication. Meaning each daughter DNA contains a strand of old parent DNA and new DNA.

replication fork

A V-shape that is created from the replication of DNA.

Uracil

A nucleotide that replaces thymine in RNA

mRNA

Takes a message from DNA in the Nucleus to ribosomes in the cytoplasm

tRNA

transfers amino acids to ribosomes

rRNA

makes up ribosomes where polypeptides are synthesized.

transcription

The process in which an RNA molocule is produced based on a DNA Template. DNA is then transcribed or copied base by base, in mRNA tRNA and rRNA.

translation

Process in which the mRNA transcript is read by a ribosome and converted into a sequence of amino acids in a poly peptide. Then, the cell changes in nucleotide into an amino acid sequence.

genetic code

Universal code that has existed for eons and allows for conversion of DNA and RNA's chemical code to a sequence of amino acids in a protein.

triplet code

During gene expression, each sequence of three nucleotide bases stands for a particular amino acid.

codon

Three base sequence in messenger RNA that during translation directs for the addition of a particular amino acid into a protein or directs termination of process.

RNA polymerase

Adds nucleotide only to 3' end of the polymer under construction

promotor

defines the start of a transcription, the direction of a transcription, and the strand to be described.

mRNA transcript

Created from stop sequence which causes RNA polymerase to stop transcribing the DNA and to release the mRNA molocule.

introns

intervening sequence found between exons in mRNA; removed by RNA processing before translation

exons

Segment of mRNA containing the protien-coding portion of a gene that remains within the mRNA after splicing had occurred.

ribozyme

Enzyme made of RNA rather than just protein

anticodon

a group of three bases that is complementary and antiparallel to a specific mRNA codon

wobble hypothesis

the first two positions in a tRNA anticodon pair obeys A-U/C-G configuration rule. However, the third position can be variable

polyribosome

The entire complex of mRNA and multiple ribosomes

initiation

the step that brings all translation components together.

elongation

the stage during protein synthesis when a polypeptide increases in length one amino acid at a time.

termination

The final step in protein synthesis. the polypeptide and components that carry out protien synthesis are separated.

proteomics

A field of biology dedicated to understanding the structure of proteins and how they function in the metabolic pathways.

DNA Polymerase

Enzyme that makes bonds between nucleotides, forming an identical strand of DNA during replication

Euchromatin

The less condensed form of eukaryotic chromatin that is available for transcription.

Heterochromatin

Highly compacted chromatin that is not accessible for transcription

Histone

protein molecule around which DNA is tightly coiled in chromatin

Nucleosome

The DNA and histone molecules form a beadlike structure called a nucleosome

Nucleotide

a building block of DNA or RNA, consisting of a sugar, a nitrogenous base and a phosphate group.

Telomere

repetitive DNA at the end of a eukaryotic chromosome