Transcription and Translation

What is a frameshift mutation?

1 or 2 extra bases are added or lost, causing the reading frame to shift over

1 nucleotide

1 pentose sugar 1 phosphate group 1 nitrogenous base

List the steps of transcription

1. DNA unwinds 2. One side of DNA "codes for a protein" 3. Genetic code of DNA is a triplet code of 3 nucleotides or bases 4. Each triplet is specific for the coding of a single amino acid 5. Sequence of triplet codes on DNA will specify the amino acid sequence on the protein 6. Major step is the synthesis of the coded "messenger" molecule - mRNA 7. mRNA is "transcribed" from DNA by complementary base pairing (mRNA has no thymine, which is replaced by uracil) 8. mRNA passes out of the cytoplasm to the ribosome

Compare and contrast RNA and DNA (draw the molecules)

1.DNA is double stranded, RNA is single stranded 2. DNA has Thymine, while RNA has Uracil 3. DNA has deoxribose sugar while RNA has ribose sugar. 1. They are both a polymer of nucleotides 2. Its sugar is linked to a phosphate group at one end and a nitrogenous base at the other end 3. They both CAN be located in the nucleus (DNA stays in the nucleus, while RNA can move in and out of the nucleus)

start codon stop anticodon

AUG UAC

Transcribe and then translate the following DNA code: TACCATTTACCG

AUGGUAAAUGGC mRNA codons: met val asn gly tRNA anticodons: STOP tyr leucine proline

Which is worse - frameshift mutation or point mutation?

Frameshift mutation

What does hemoglobin do?

Hemoglobin is the protein molecule in red blood cells that carries oxygen to cells

What are introns vs. exons?

Introns are removed and exons are joined to form coding

How does sickle cell anemia come about?

It is a single point mutation resulting from one amino acid swap; cell trait normally comes from African descents

What type of biomolecule are RNA and DNA?

Nucleic Acids

Where does transcription take place?

Nucleus

What is the enzyme involved in Transcription?

RNA polymerase

What are the molecules involved in translation?

RNA, tRNA, mRNA

Where is hemoglobin found?

Red blood cells of the body

What molecule does transcription start and end with?

Starts with DNA and ends with mRNA

What molecule does translation start and end with?

Starts with mRNA and ends with proteins

How does translation stop once a stop codon is reached?

The end of translation occurs when the ribosome reaches one or more STOP codons. (The nucleotides from this point to the poly(A) tail make up the 3'-untranslated region [3'-UTR] of the mRNA.)

List the steps of translation

The ribosome binds to mRNA at a specific area. The ribosome starts matching tRNA anticodon sequences to the mRNA codon sequence. Each time a new tRNA comes into the ribosome, the amino acid that it was carrying gets added to the elongating polypeptide chain.

What are the three stop codons?

UAA, UAG, UGA

What is a point mutation?

a mutation affecting only one or very few nucleotides in a gene sequence

polypeptide chain

a sequence of amino acid

What is sickle cell anemia?

a severe hereditary form of anemia in which a mutated form of hemoglobin distorts the red blood cells into a crescent shape at low oxygen levels. it is a single point mutation resulting from one amino acid swap. gives you protection from maleria

4 nucleotides in mRNA

adenine, cytosine, guanine and uracil

4 nucleotides in DNA

adenine, cytosine, guanine, and thymine

Secondary Structure

alpha helix and beta pleat; hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern

monomer of proteins

amino acid

Examples of proteins

amino acids and hemoglobin

Primary Structure

amino acids link together in dehydration reactions (polypeptide chain)

proteins

biomolecule contain carbon, hydrogen and oxygen also contain sulfur, phosphate, nitrogen

examples of mutations

blonde hair, blue eyes, down syndrome

peptide bonds

bonds amino acids

4 biomolecules

carbohydrates - glucose protein - amino acids lipids - glycerol and fatty acid chains nucleic acid - nucleotide

translation

change the language mRNA --> proteins how the mRNA is used to create proteins

P site

contains a charged tRNA holding the growing polypeptide chain

Where does translation take place?

cytoplasm

DNA

deoxyribose nucleic acid A, T, C, G double helix

functional proteins

do jobs

RNA polymerase

enzyme in transcription "unzips" DNA adds new RNA nucleotides to the mRNA molecule will bind to the TATA box and transcribe the entire gene

Quaternary Structure

final form, 4 globular proteins link together to form a single functioning protein, protein consisting of more than one amino acid chain

Tertiary Structure

first functional stage; R group determines chemical reactivity of amino acid; each amino acid has a unique R group; R groups bond with one another to form tertiary structure (global structure); three dimensional folding pattern of a protein due to side chain interactions

A site

hold the next charged tRNA new tRNA enter

What is the start codon?

most common is AUG

What is the monomer of RNA and DNA?

nucleotides

polymer of proteins

polypeptide (peptide chain)

TATA box

promoter binds to the rna polymerase

structural proteins

provide shape

How does an mRNA molecule become stabilized in order to leave the nucleus?

receives a 5' cap and a 3' poly (A) tail before introns are removed and the mRNA is considered ready for translation

transcription

rewrite DNA --> mRNA

mRNA

ribose A, U, C, G single helix

codon

set of 3 nucleotides on an mRNA molecule that codes for a specific amino acid

Examples of proteins with quaternary structure

sulin, hemoglobin, and most enzymes

tRNA

transports RNA it is "uncharged" when it is empty it is "charged" when it is carrying an amino acid each tRNA carries a specific amino acid transports amino acids (basic building blocks of proteins)

nonsense

when the wrong base is put in the mRNA by mistake --> codon = one of the stop signals

missence

when the wrong base is put in the mRNA by mistake, leading to a different codon and different amino acid

ribosomal complex

where mRNA meets tRNA amino acids attach to the 3' end of tRNA has the A site, P side, and E site large sub unit is above the strand small sub unit is below the strand

E site

where uncharged tRNAs leave