BIO 215 Ch. 8

Genes to Proteins

Protein

Macromolecules made of repeating amino acid and subunits 

Amino Acids

The building block compounds that proteins are made of 

Gene Expression

The process where a cell uses the instructions encoded in a gene to create a functional product, such as a protein

Regulatory Sequence

On and off switch for a gene

Coding Sequence

Controls the amino acid sequence of the protein

Transcription

The process of making messenger RNA (mRNA) copy of the gene

Messenger RNA (mRNA)

A single stranded molecule of RNA that carries genetic instructions from a cell’s DNA to its protein-making machinery

Translation

The process of using mRNA copy as a set of instructions to assemble amino acids into a protein

RNA Polymerase

An enzyme that synthesizes an RNA strand from a DNA template during transcription

Ribosome

The cellular structure that builds proteins by translating mRNA

Codon

A sequence of 3 consecutive nucleotides in a DNA or RNA that corresponds to a specific amino acid or a stop signal during protein synthesis

Transfer RNA (tRNA)

A small RNA molecule that acts as an adapter during protein synthesis by bringing the correct amino acid to the ribosome

Anticodon

A sequence of three nucleotides on a transfer RNA (tRNA) molecule that is complementary to a corresponding messenger RNA (mRNA) codon

Genetic code

Universally makes it possible for humans to create genetically modified organisms

Transgenic

Organisms that have received recombinant genes

Genetic Engineering

The manipulation of an organism’s genome using biotechnology to add, remove or alter traits

Recombinant Gene

A genetically engineered gene that contains portions of genes naturally found together

Genetically Modified Organisms (GMO)

Organisms whose genomes have been altered through modern genetic engineering techniques, sometimes to contain new genes

Gene Therapy

Modifies or replaces defective human genes with healthy ones

Similarities and differences between amino acids

Similarities: All 20 amino acids share the same basic core structure

Differences: Each type of amino acid has a unique chemical side chain

How does a protein achieve it’s final 3-dimensional shape?

Determined by its amino acid sequence and how their side chains interact

Relationship between protein shape and function

Shape determines function. Change the shape → change the function

Relationship between proteins, DNA, genes and chromosomes

Chromosomes hold DNA → DNA contains genes → genes code for proteins

Regulatory sequence vs Coding sequence

Regulatory is on/off switch (when/where to express, while coding controls the amino acid order

Two steps of gene expression & mRNA role

1. Transcription

2. Translation

mRNA carries DNA code from nucleus to cytoplasm

Steps of Transcription

1. RNA polymerase binds regulatory sequence

2. DNA unwinds

3. RNA poly binds complementary mRNA

4. mRNA leaves nucleus

mRNA transcription of DNA AGTCGAT

UCAGCGUA (T becomes U in RNA)

Steps of Translation

1. mRNA meets ribosome

2. Ribosome reads codons (sets of 3)

3. tRNA brings matching amino acids

4. Chain forms and folds into protein

Codon vs Anticodon

Codon: 3-nucleotide sequence on mRNA

Anticodon: 3-nucleotide sequence on tRNA

Find tRNA anticodon for mRNA codon AUG

UAC (Complementary base pairing)

How is a recombinant gene created?

Enzymes cut and join pieces of genes from different sources together

How is spider silk made in transgenic yeast?

Put recombinant spider gene (with yeast regulatory sequence) into yeast cells to produce spidroin

How is the human insulin made in transgenic bacteria?

Insert human insulin coding sequence paired with bacterium regulatory sequence into bacteria

Universal eugenic code and its importance?

Means that all organisms use the same cod and it allows us to make transgenic organisms (bacteria/yeast making human or spider proteins)