HOW PROTEINS ARE MADE

Chapter 10

Section 1 – From Genes to Proteins Gene – A segment of DNA that codes

for a specific protein. RNA – Ribonucleic Acid

A type of nucleic acid (like DNA)Used, along with DNA, to make proteins.

Section 1 – From Genes to Proteins 3 Primary Differences of RNA vs. DNA

RNA usually has one strand, DNA has two

RNA has ribose for a sugar, DNA has deoxyribose

RNA uses Uracil instead of Thymine

Section 1 – From Genes to Proteins Transcription – Transferring information

from DNA (the gene) to RNA. Translation – Transferring information

from RNA to make a protein.Different types of RNA are used for these

processes

Section 1 – From Genes to Proteins Gene Expression (Protein Synthesis)

– The entire process (translation and transcription) by which proteins are made.

Section 1 – From Genes to Proteins TRANSCRIPTION

Step 1: RNA polymerase binds to the gene’s promoter (beginning of gene).

Step 2: The two DNA strands unwind and separate – DNA helicase does this

Step 3: Complementary RNA nucleotides are added by RNA polymerase.

Section 1 – From Genes to Proteins

Section 1 – From Genes to Proteins There are different types of RNA used

during Gene Expression mRNA – Messenger RNA. Carries

instructions from gene (DNA) and delivers it to site of translation.Codons - RNA is written as a series of

three-nucleotide sequences. These are called Codons.

Section 1 – From Genes to Proteins

Chart on Test

Section 1 – From Genes to Proteins Transfer RNA (tRNA) molecules are

single strands of RNA that temporarily carry a specific amino acid on one end.Anticodon – A three-nucleotide

sequence in tRNA that complements a codon (from mRNA)

Work with mRNA to produce amino acids.

Section 1 – From Genes to Proteins Translation

Step 1: Ribosome attaches to mRNAStep 2: tRNA carrying amino acid attaches

to A siteStep 3: Peptide bond forms between amino

acids that have just arrived and those already in protein.

Step 4: tRNA detaches.Step 5: Repeat 2-4 until protein is completeStep 6 Ribosome detaches from mRNA.

Section 1 – From Genes to Proteins Ribosomal RNA (rRNA) - parts of RNA

molecules that are part of the structure of ribosomes.

Ribosomes – Structures that assist in the manufacture of proteins.

Section 2 – Gene Regulation and Structure Gene Regulation – Control of

transcription in gene expressionSpecifically, when RNA polymerase binds

to a gene Transcription Factors – Arrange RNA

Polymerases on the correct area of the promoter

Section 2 – Gene Regulation and Structure

Section 2 – Gene Regulation and Structure Not all segments of DNA code for proteins Introns – long segments of nucleotides

that have no coding informationCut out of mRNA by spliceosomes. Introns = Stay IN the nucleus

Exons – Segments of DNA that are expressedExons = Expressed

Section 2 – Gene Regulation and Structure

Section 2 – Gene Regulation and Structure Mutation – Any change in the

nucleotide sequence. There are a wide variety of mutations.

Section 2 – Gene Regulation and Structure Point Mutation - a single nucleotide

changesSubstitution – one nucleotide replaces

another Frameshift Mutation – Anytime a

mutation causes the wrong three-nucleotide sequence to be read.Insertion – nucleotides are inserted into a

gene.Deletion - segments of a gene are lost