Unit 6.2: Protein Synthesis

Central Dogma

The flow of genetic information: DNA → RNA → Protein.

mRNA (messenger)

type of RNA that carries genetic instructions from DNA to the ribosome for protein synthesis.

rRNA (ribosomal)

type of RNA that forms part of the ribosomal subunits

tRNA (transfer)

type of RNA that carries amino acids to the ribosome to make the growing protein and contains an anticodon

Transcription

The process of copying DNA into mRNA.

Translation

The process where ribosomes use mRNA to assemble proteins.

Ribosomes

Organelles that assemble proteins by linking amino acids using mRNA instructions.

Codon

A three-nucleotide sequence on mRNA that codes for a specific amino acid.

Amino Acid

subunit/monomer that are the building blocks of proteins (polypeptides).

Mutation

A change in the DNA sequence that may affect protein structure or function.

What are the similarities between DNA and RNA?

Both are nucleic acids made of nucleotides and involved in genetic processes.

What are the differences between DNA and RNA?

DNA is double-stranded, uses deoxyribose, and contains thymine. RNA is single-stranded, uses ribose, and contains uracil.

What is the starting molecule for transcription?

DNA.

What is produced in transcription?

mRNA.

Where does transcripttion happen in Eukaryotes?

In the nucleus.

How many times does transcription occur to make needed proteins?

As many times as needed.

What is the starting molecule for translation?

mRNA.

What is produced in translation?

A protein (polypeptide chain).

Where does translation take place?

In the cytoplasm at the ribosome.

What organelle forms peptide bonds in translation?

Ribosome.

What is the function of mRNA?

Carries genetic instructions from DNA to the ribosome.

What is the function of rRNA?

Forms part of the ribosome and helps link amino acids together.

What is the function of tRNA?

Transfers amino acids to the ribosome based on the mRNA codon.

What does the first tRNA molecule do at the beginning of translation?

Binds to the start codon (usually AUG) and brings the first amino acid.

What makes up proteins?

Chains of amino acids.

What is the portion of DNA that codes for a specific protein called?

A gene.

How can you summarize the process of protein synthesis?

DNA is transcribed into mRNA, which is then translated into a protein.

What are the steps to transcribe and translate a DNA sequence?

1. Transcribe DNA into mRNA (A→U, T→A, C→G, G→C)

2. Divide mRNA into codons

3. Use a codon chart to find each amino acid.

If a gene is like a sentence, a codon is like a…?

A word.

If a chromosome is like a novel, what best represents a gene?

A chapter.