Unit 4 DNA and the Central Dogma of Biology Vocabulary

Chromosomes

DNA wrapped around histones

Histones

proteins that chromosomes wrap around

Genes

sections of DNA that determine traits

Chromatids

identical copies of chromosomes

Centromere

region of a chromosome where chromatids are held together

Erwin Chargaff (1950)

chemist who figured out that the bases of DNA were paired in a specific order (Chargaff's rules)

Chargaff's Rule

rule stating that the bases of DNA pair in a specific order: Adenine with Thymine and Cytosine with Guanine

Rosalind Franklin

female scientist who established that DNA existed in a spiral 3D shape ; created Photo-51

Photo-51

x-ray image of DNA's structure that took 100 to get and 1 year to fully analyze; produced by Franklin

James Watson & Francis Crick (1953)

scientists who created the first accurate DNA model using Chargaff's and Franklin's research

double helix

two strands of nucleotides wound about each other; structure of DNA

nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

Maurice Wilkins

Rosalind Franklin's supervisor who aided with the first DNA model

Fredrick Griffith's Experiment

experiment with 4 steps involving injecting mice with either capsulated or no capsule bacteria; discovered DNA carries genes

DNA (Deoxyribonucleic Acid)

double stranded nucleic acid present in all living cells that contains all the instructions determining the traits a living organism needs to live

RNA (Ribonucleic Acid)

single stranded segment of DNA that can be converted into protein and make structures

Ribose

sugar in RNA

Uracil

nucleotide that replaces Thymine in RNA

DNA Replication

the process of copying DNA

DNA Helicase

enzyme that unwinds DNA

Replication Fork

Y-shaped region on a replicating DNA molecule where new strands are growing

DNA Polymerase

enzyme that adds complementary nucleotides to bind sugar and phosphates

Leading Strand

new DNA strand continuously created in the 5' to 3' direction

Lagging Strand

DNA strand that grows through Okazaki fragments in a 5' to 3' direction

Okazaki Fragments

small fragments of DNA produced on the lagging strand during DNA replication that are bound together with DNA ligase

Transcription

process where a mRNA is created by RNA Polymerase

mRNA (Messenger RNA)

single stranded RNA molecule holding the instructions how to to make proteins

Translation

process where mRNA gets turned into protein

Ribosome

site where proteins are made

tRNA (Transfer RNA)

type of RNA molecule that transfers amino acids to ribosomes during protein synthesis

Codon

sequence of three nucleotides

Anticodon

sequence of three nucleotides that recognizes and binds to a specific codon on mRNA

Mutagen

chemical or physical agent that can cause mutations

Mutation

change in a DNA sequence

Deletion

chromosomal mutation where a base is left out of the copying

Insertion

chromosomal mutation where a base pair is added during the copying

Substitution

chromosomal mutation where a base pair is replaced during the copying

Translocation

chromosomal mutation where a part of a chromosome breaks off to attach to another

Duplication

chromosomal mutation where an extra copy of all or a part of a chromosome is produced

Inversion

chromosomal mutation where the direction of a chromosome is reversed

Point Mutation

gene mutation where one base is substituted for another

Frameshift Mutation

gene mutation where a base is either added or removed, causing a shift in the reading frame and affecting many genes

Silent Mutation

gene mutation where a base is changed but the result is the same as the non-mutant DNA, resulting in no outward change

Nonsense Mutation

gene mutation where a codon is changed to a stop codon