Biology 11 and 12

genetic code

The nucleotide triplets of DNA and RNA molecules that carry genetic information in living cells.

anticodon vs codon

Anticodon: A sequence of three adjacent nucleotides located on one end of transfer RNA. It bounds to the complementary coding triplet of nucleotides in messenger RNA during translation phase of protein synthesis. Codon: A set of three adjacent nucleotides, also called triplet, in mRNA that base-pair with the corresponding aniticodon of tRNA molecule that carries a particular amino acid.

histone

Any of a group of basic proteins found in chromatin.

double helix

A conformation or shape describing a structure that typically consists of two matching helices intertwined about a common axis, such as the structure of the DNA. Complementary base pairing: The standard arrangement of bases in nucleotides in relation to their opposite pairing, such as thymine being paired with adenine and cytosine paired with guanine.

ribosome

A minute particle composed of protein and ribonucleic acid (RNA) that serves as the site of protein synthesis. Polyribosome: A cluster of ribosomes held together by a strand of messenger RNA that each ribosome is translating.

silent mutation

A mutation occurs, but the mRNA translates the sequence into the sequence that was replicated before. The three letter condon can have an amino acid attached, this is called redundancy.

exon

A segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence.

intron

A segment of a DNA or RNA molecule that does not code for proteins and interrupts the sequence of genes.

Triple Code

A sequence of three bases along a single strand of DNA. Each triplet code is 'read' and calls for a specific amino acid.

promoter

A site on DNA to which the enzyme RNA polymerase can bind to initiate the transcription of DNA into RNA.

Template

A structure that in some direct physical process can cause the patterning of a second structure, usually complementary to it in some sense.

Transcription vs Translation

Transcription: DNA is read to make a mRNA in the nucleus of our cells. Translation: Reading the mRNA to make a protein in the cytoplasm.

mRNA transcript vs RNA polymerase

mRNA Transcript: The first step of gene expression, in which a particular segment of DNA is copied into RNA (mRNA) by the enzyme RNA polymerase. RNA polymerase: An enzyme that synthesizes the formation of RNA from a DNA template during transcription.

Bases in DNA

Adenine: One of the bases that form part of a nucleotide, the structures that are present in dna chains. Pairs with Thymine. Cytosine:A pyrimidine base (nitrogenous base) found in dna and rna that pairs with guanine. Thymine: Pyrimidine base (nitrogenous base) found in dNA (in place of uracil of RNA). Paired with adenine in DNA sequences and is replaced by uracil in mRNA. Guanine:A purine base found in dna and RNA; pairs with cytosine. Uracil: A nitrogen-containing base found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine.

Point mutation vs base substitution

Base Substitution: changes the identity of a base or bases. Point Mutation: A substitution of a single base leads to a different amino acid in the protein that is made from the gene.

Translocation

Chromosomal translocation, that is a chromosomal segment is moved from one position to another, either within the same chromosome or to another chromosome.

DNA replication vs Semiconservative replication

DNA Replication: Is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. Replication is an essential. Semi: Relating to or being genetic replication in which a double-stranded molecule of nucleic acid separates into two single strands each of which serves as a template for the formation of a complementary strand that together with the template forms a complete molecule

DNA polymerase

Enzymes involved in template directed synthesis of dna from deoxyribonucleotide triphosphates.

steps of translation

Initiation: mRNA binds to the small ribosomal subunit and causes 2 ribosomal units to associate. Elongation: polypeptide lengthens due to the tRNA adding amino acids. Termination: A stop codon on the mRNA causes the ribosome to fall off the mRNA.

mutations

Results from errors in replication and can involve changes, additions, or deletions to nucleotides. Mutagens: Chemicals or radiation that cause mutation. Germ-Line: these mutations will be passed to future generations (HUMAN GENE POOL), and are important for evolution. Somantic: not passed to future generations but passed to all other somatic cells derived from it.

Frame shift mutation

insertion adds a base or bases. deletion removes a base or base. If one or two of the bases are changed then the codon will be shifted. It won't make sense due to the different codon. This throws the reading frame of the genetic message out of register.

types of RNA

rRNA: Ribosomal RNA, joins with proteins to form ribosomes. tRNA: Transfer RNA, transfers amino acids to a ribosome where they are added to a forming protein. mRNA: Messanger RNA, carries genetic information from DNA to the ribosomes.