Protein Synthesis and the Central Dogma of Biology

Central Dogma of Biology

The process by which DNA is transcribed to RNA and then translated to protein.

Instructions for building proteins

DNA provides the instructions for building proteins.

Location of DNA in eukaryotic cells

DNA is located in the nucleus.

Location of DNA in prokaryotic cells

DNA is located in the cytoplasm (free-floating).

Ribosomes

Cellular structures that build proteins, located in the cytoplasm.

RNA

A nucleic acid polymer composed of nucleotides, similar but not identical to DNA.

Sugar in RNA

RNA contains ribose sugar.

Nitrogen base in RNA

RNA contains uracil (U) instead of thymine (T).

Size comparison of DNA and RNA

DNA is a longer molecule while RNA is a shorter molecule.

Transcription

The process that uses DNA as a template to make mRNA.

Base pairing in RNA

In RNA, uracil (U) pairs with adenine (A).

Base pairing in DNA

In DNA, adenine (A) usually pairs with thymine (T).

Process using mRNA to make a protein

Translation.

Flow of information in eukaryotic cells

Information flows from DNA to RNA in the nucleus and then to proteins in the cytoplasm.

Difference between DNA and RNA

DNA has deoxyribose sugar, while RNA has ribose sugar.

Difference between DNA and RNA

DNA contains thymine (T), while RNA contains uracil (U) instead.

Difference between DNA and RNA

DNA is a longer molecule, while RNA is a shorter molecule.

Function of RNA

RNA serves as a copy of the genetic instructions from DNA that can leave the nucleus.

Location of ribosomes

Ribosomes are located in the cytoplasm.

Template for mRNA

DNA serves as a template for the synthesis of mRNA.

Complementary base pairing

In RNA, U pairs with A, which differs from DNA where A pairs with T.

mRNA

Messenger RNA: the instructions for making a protein are encoded within its sequence of nucleotides.

tRNA

Transfer RNA: attaches to amino acids and then transfers them to the ribosome during translation.

rRNA

Ribosomal RNA: combines with ribosomal proteins to make up the actual ribosome.

Transcription

The process of making an RNA copy of a piece of DNA sequence.

Translation

The process of assembling amino acids according to the RNA sequence to eventually make a protein.

Amino Acid Coding

Each group of THREE letters (three bases) codes for ONE amino acid.

Location of Transcription

Occurs inside the nucleus.

Location of Translation

Occurs in the cytoplasm.

Gene Expression

A gene would be expressed if it coded for a protein that is needed inside that particular cell.

Non-expressed Genes

If a cell doesn't need certain proteins, then the associated genes won't be expressed.

Types of RNA

There are three main types of RNA: mRNA, tRNA, and rRNA.

Purpose of Transcription

To make an RNA copy of a piece of DNA sequence.

Purpose of Translation

To assemble amino acids according to the RNA sequence.

DNA Template to mRNA

Transcription of DNA A T C G G A T A C results in mRNA U A G C C U A U G.

Codon

A sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.

Nucleus

The organelle where transcription occurs.

Cytoplasm

The location where translation occurs.

Protein Synthesis

The process of creating proteins based on the instructions carried by mRNA.

Ribosome

The molecular machine that assembles amino acids into proteins during translation.

Gene Regulation

The process by which cells control the expression of genes.