DNA, Proteins, and Enzymes

Flashcards covering key terms and concepts related to DNA, proteins, enzymes, and their roles in biological processes.

DNA

Acts as the master blueprint; contains sequences of nucleotides called genes that provide instructions for protein structure.

Transcription

The process in the nucleus where RNA polymerase creates a pre-mRNA strand complementary to the DNA template strand.

what are the 3 steps of transcription?

Initiation: RNA polymerase binds to the promoter region of a gene and unwinds the DNA strands.

​Elongation: RNA polymerase moves along the template strand, joining complementary RNA nucleotides to create a pre-mRNA molecule.

​Termination: RNA polymerase reaches a stop signal and detaches, releasing the pre-mRNA strand.

RNA Processing

Eukaryotic process where introns are removed and exons are spliced, with a 5' methyl cap and 3' poly-A tail added.

Translation

The process where mRNA is translated into a polypeptide chain by tRNA molecules at the ribosome.

How is the mRNA message turned into a polypeptide chain at the ribosome?

Attachment: The processed mRNA attaches to a ribosome in the cytosol.

​Codon Recognition: The ribosome "reads" the mRNA in triplets called codons.

​tRNA Delivery: tRNA molecules with matching anti-codons bring specific amino acids to the ribosome.

​Peptide Bond Formation: The ribosome joins the amino acids together via peptide bonds to grow the protein chain.

​Termination: When a "stop" codon is reached, the polypeptide is released for folding.

Enzyme

Biological catalysts that speed up reactions by lowering activation energy.

Active Site

A pocket on the enzyme where the reaction occurs.

Substrate

The specific molecule(s) that bind to the active site to be converted into products.

Denaturation

A structural change where hydrogen bonds break, leading to loss of enzyme function.

Restriction Endonucleases

Enzymes that cut DNA at specific recognition sites, acting as 'molecular scissors'.

Blunt Ends

Straight cuts in DNA with no overhanging nucleotides.

Sticky Ends

Cuts that leave overhanging single-stranded DNA tails, useful for recombinant DNA.

DNA Ligase

An enzyme that joins two DNA fragments by catalyzing phosphodiester bond formation.

PCR Process

A series of steps (Denaturation, Annealing, Extension) to amplify DNA.

What temp is Denaturation and what happens?

95⁰c - heat breaks the hydrogen bonds between DNA strands, separating them.

what temp is Annealing and what happens?

50-55⁰c - Primers bind to complementary sequences on the single-stranded DNA

what temp is Extension and what happens?

72⁰c - Taq polymerase adds nucleotides to the primers, synthesising new DNA strands

Taq Polymerase

Heat-resistant enzyme that synthesizes new DNA strands during PCR.

Agarose Gel

A matrix that sorts DNA fragments by size during gel electrophoresis.

Electric Current

Provides the driving force in gel electrophoresis, moving negatively charged DNA towards the positive electrode.

GMO

Any organism whose genetic material has been altered through genetic engineering.

TGO

A type of GMO that contains a gene from another species.

Independent Variable (IV)

The factor that is changed in an experiment.

Dependent Variable (DV)

The factor that is measured in an experiment.

Controlled Variables

Factors kept constant to ensure a fair test.

Control Group

The group not exposed to the independent variable, serving as a baseline for comparison.

Precision

How close multiple measurements are to each other.

Accuracy

How close a measurement is to the true or accepted value.

Qualitative Data

Descriptive data, such as color or appearance.

Quantitative Data

Numerical data, such as measurements or counts.