Unit 6- DNA

DNA

The molecule inside cells that holds the genetic code or instructions for life.

Deoxyribose

The sugar that forms part of the "backbone" of DNA.

Double Helix

The shape of DNA, which looks like a twisted ladder.

Gene

A specific section of DNA that gives instructions for making a protein.

Allele

One version of a gene (Ex. blue eyes vs. brown eyes).

Genome

All the genetic material or DNA of an organism.

Chromatin

Uncoiled DNA inside the nucleus. It looks like a tangled thread.

Chromosome

Tightly coiled DNA around proteins. Happens when a cell is getting ready to divide.

DNA Replication

The process where a cell makes an exact copy of its DNA.

Nucleotide

The basic building block of DNA and RNA. It consists of a sugar, a phosphate, and a nitrogen base.

Adenine

A nitrogen base found in DNA and RNA. Adenine pairs with thymine in DNA and with uracil in RNA.

Thymine

A nitrogen base found in DNA but not in RNA. Thymine pairs with Adenine through complementary base pairing.

Cytosine

A nitrogen base found in DNA and RNA. Cytosine pairs with guanine through complementary base pairing.

Guanine

A nitrogen base found in DNA and RNA. Guanine pairs with cytosine through complementary base pairing.

Uracil

A nitrogen base found only in RNA (it pairs with adenine).

Hydrogen Bond

A weak chemical bond that holds the two strands of DNA together like rungs on a ladder.

RNA

A single-stranded molecule similar to DNA that helps read genetic instructions and build proteins.

Ribose

The sugar found in RNA nucleotides.

mRNA

RNA that carries a copy of genetic instructions from the DNA to the ribosome.

tRNA

RNA that brings specific amino acids to the ribosome to build proteins.

rRNA

RNA that makes up the main structure of ribosomes.

Protein Synthesis

The entire process of using DNA instructions to build proteins.

Transcription

The process of copying a gene's DNA code into a strand of mRNA.

Translation

The process where the ribosome reads mRNA to assemble amino acids into a protein.

Codon

A sequence of three nucleotides on mRNA that codes for a specific amino acid.

Anticodon

A sequence of three nucleotides on tRNA that matches up with an mRNA codon.

Start Codon

The specific three-letter code that tells the cell where to begin building a protein.

Stop Codon

The specific three-letter code that tells the cell where to finish building a protein.

Polypeptide

A chain of amino acids, which forms the structure of a protein.

Peptide Bond

The chemical bond that connects amino acids together in a protein chain.

Mutation

A mistake or change in the DNA sequence.

Insertion Mutation

An extra nucleotide base is added to the DNA sequence.

Deletion Mutation

A nucleotide base is removed from the DNA sequence.