bio studying (molecular genetics)

DNA

Deoxyribonucleic acid; molecule that stores genetic information.

Double helix

Twisted ladder shape of DNA.

Nucleotide

Building block of DNA made of phosphate, sugar, and nitrogen base.

Nitrogen bases

The 4 DNA bases: adenine, thymine, cytosine, guanine.

Complementary base pairing

A pairs with T, and C pairs with G.

Gene

Section of DNA that codes for a protein.

Chromosome

Tightly coiled DNA structure.

Genome

All the DNA in an organism.

DNA replication

Process of copying DNA before cell division.

Helicase

Enzyme that unzips DNA during replication.

DNA polymerase

Enzyme that adds new nucleotides during replication.

Semi-conservative replication

Each new DNA molecule contains 1 old strand and 1 new strand.

Protein synthesis

Process of making proteins using DNA instructions.

RNA

Ribonucleic acid involved in protein synthesis.

Difference between DNA and RNA

RNA is single stranded, has ribose sugar, and uses uracil instead of thymine.

mRNA

Messenger RNA that carries instructions from DNA to ribosome.

tRNA

Transfer RNA that brings amino acids to ribosome.

rRNA

Ribosomal RNA that makes up ribosomes.

Transcription

Process of copying DNA into mRNA in the nucleus.

RNA polymerase

Enzyme that builds mRNA during transcription.

RNA base pairing

A pairs with U, T pairs with A, C pairs with G, G pairs with C.

Translation

Process where ribosome reads mRNA to build a protein.

Codon

Group of 3 RNA bases that codes for an amino acid.

Start codon

AUG; starts translation and codes for methionine.

Stop codon

Codon that tells translation to stop.

Anticodon

3-base sequence on tRNA that matches mRNA codon.

Amino acid

Building blocks of proteins.

Peptide bond

Bond that joins amino acids together.

Polypeptide

Chain of amino acids that folds into a protein.

Genetic code

Set of codons used to code for amino acids.

Mutation

Change in DNA sequence.

Substitution mutation

One base is replaced with another.

Insertion mutation

Extra base added into DNA sequence.

Deletion mutation

Base removed from DNA sequence.

Frameshift mutation

Mutation caused by insertion or deletion that shifts reading frame.

Mutagen

Something that causes mutations.

Examples of mutagens

UV radiation, X-rays, cigarette smoke, chemicals.

Gene regulation

Process of turning genes on or off.

Biotechnology

Using organisms or DNA technology for practical purposes.

Recombinant DNA

DNA made by combining DNA from different organisms.

Plasmid

Small circular DNA found in bacteria.

Vector

Carrier used to transfer genes into cells.

Restriction enzyme

Enzyme that cuts DNA at specific sequences.

DNA ligase

Enzyme that joins DNA fragments together.

PCR

Polymerase chain reaction; used to make many copies of DNA.

Purpose of PCR

Amplify DNA for testing and analysis.

Gel electrophoresis

Method used to separate DNA fragments by size.

How gel electrophoresis works

Smaller DNA fragments move farther through the gel.

DNA sequencing

Finding the exact order of DNA bases.

Human Genome Project

Project that mapped all human genes.

Cloning

Making genetically identical organisms.

Stem cells

Undifferentiated cells that can become many cell types.

Genetic engineering

Directly changing an organism’s DNA.

Gene therapy

Replacing faulty genes with healthy ones.

GMO

Genetically modified organism.

Main purpose of DNA

Store genetic instructions.

Main purpose of proteins

Control cell structure and function.

Main steps of protein synthesis

Transcription and translation.

Location of transcription

Nucleus.

Location of translation

Ribosome.

Purpose of transcription

Copy DNA instructions into mRNA.

Purpose of translation

Build proteins from mRNA instructions.

Why mutations matter

They can change proteins and traits.

Importance of biotechnology

Allows humans to manipulate DNA for medicine, agriculture, and research.