DNA and RNA Deoxyribonucleic acid DNA is made

DNA and RNA

• Deoxyribonucleic acid (DNA) is made of ______. nucleotides Remember that nucleotides are made of three parts: ______________ Phosphate group, 5 -carbon ______________ sugar and a nitrogen base. ____

• The nucleotides that make up DNA contain the sugar deoxyribose and one of ______ four different nitrogen bases: adenine, thymine, guanine ______________ or cytosine ______

• In 1953, scientists __________________ James Watson and Francis Crick discovered that DNA is made of two chains of nucleotides joined together. The nucleotides bond at their nitrogen bases to hold the two strands together. The bases pair together: Adenine with Thymine and Guanine _________________ with Cytosine

• Write a complimentary strand of bases for the following sequence: A T T G C G T A G C T G A T C

• If you know the percentage of one nitrogen base in a strand of DNA then you can estimate the amounts of the other three. Chargaff’s Rule This is ________.

• Watson and Crick with the help of Rosalind Franklin also discovered that DNA is twisted in a shape called a double helix DNA looks like a ______. twisted ladder. base pairs make up the • The ______ “steps” of the ladder. And the sugar and phosphate make up the “sides” of the ladder. This is called the sugar-phosphate backbone _____________.

• DNA carries the code for proteins. Proteins guide all cell and body chemistry. • Proteins are made from strands amino acids of ______, so DNA actually codes for specific ribosomes amino acids and the _____ assemble them to make proteins.

• In order for the proteins to be made correctly, three processes must occur: DNA replication, RNA transcription, and protein translation.

DNA Replication • DNA replication is how DNA S copies itself during the ___ interphase in order phase of ______ to pass traits on to new cells. The new DNA is an exact copy of the existing DNA.

1. An enzyme called _____ helicase breaks hydrogen bonds between the _____ nitrogen bases and the two strands of DNA unwind and separate. 2. Free nucleotides that are floating around in the cell attach and bond to the unwound exposed bases to form new pairs. They only bond with the __________. (Acomplimentary base T and C-G)Enzymes called DNA Polymerases help bond the nucleotides.

3. The sugar and phosphate parts of the free nucleotides bond together forming a backbone for the _________. new strand of DNA 4. The result is two identical strands of DNA consisting of one side of the “new” DNA and one side of the “old” DNA. This is called _________. semi-conservative

• • • The picture above is a model of ____. DNA does X What represent in the picture above? ________ a nucleotide What is the shape of the picture above? _______ double helix

RNA • Ribonucleic acid (RNA) is also made of nucleotides, but they are _____ different than the ones in DNA.

• RNA has _______ ribose sugar instead of deoxyribose and it contains a different nitrogen base. Instead of thymine, RNA has uracil It still contains ______. adenine, cytosine and guanine. single-stranded RNA is also ________ whereas DNA is double-stranded.

Transcription • DNA stays in the ____ nucleus of cells. In order to get the protein codes to the ribosome for assembly, a copy must be made and sent to them. This copy is made of RNA. The process that makes the copy is RNA transcription called _________.

unwinds a small – DNA _______ section like it does in replication. – Free RNA nucleotides pair with the unwound section and their sugar and phosphate parts bond to form the backbone.

– Once the RNA copy is made it breaks away from the DNA and bonds back together the DNA __________. – The new strand of RNA leaves the nucleus and takes its information into the cytoplasm and to the _____ ribosome.

Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) RNA polymerase RNA DNA

transcription animation

• Write a complimentary strand of RNA for the following DNA base sequence: A T T G C T G A C G T C G A T C

• RNA has many responsibilities in the cell. There are three types of RNA messenger RNA (m. RNA)- made – _____ during transcription; delivers amino acid codes to the ribosomes ribosomal RNA (r. RNA)- makes up – _____ ribosomes; reads codons transfer RNA (t. RNA)- transfers – _____ amino acids to ribosomes

• A isr. RNA _____, B is t. RNA _____ and C is _____. m. RNA

• • Every sequence of three nitrogen codon bases in m. RNA is called a ______. EX: AUC, UUU, GCA These different codons hold information to make specific amino acids. Since there are four bases, __ 64 different codon combinations are possible. These 64 combinations make up the codes for the ___ 20 different amino acids.

• An _____ anticodon is a nitrogen base sequence that is the opposite of the original codon. It is found on t. RNA and has the corresponding ______ amino for theacid codon attached to it.

• Write the correct anticodon for the following codons: – – CUGAAGGCUUUC-

Translation • m. RNA carries the codons to ribosomes so that proteins _____ can be assembled using the correct amino acid sequence. This process is called translation and involves all ______ three types of RNA.

a. Once the m. RNA has attached to the ribosome, t. RNA binds to the start codon (always AUG) and _______ begins forming a chain of amino acids.

b. As the m. RNA code is being “translated”, it slides through the ribosome. A new t. RNA _____ attaches at every codon, bonding its amino acid to the previous and then it falls off. c. The m. RNA codon determines the Amino acid that is joined to the ______ growing protein. d. The newly formed protein falls off when the ribosome reads the stop codon ______.

translation animation

t. RNA m. RNA Ribosome m. RNA anticodon • What process is shown above? ______ translation • Label structures A-G.

DNA m. RNA t. RNA Amino acid UAC TAT GCA

Mutations • Sometimes there are mistakes in the DNA sequence that may affect the genetic information passed to offspring. This is mutation called a _____. • Some mutations are small and undetected, but some may cause problems.

• Things that cause mutations in mutagens Some DNA are called _____. examples are X rays, UV light, and radioactive substances. • There are two different types gene mutations of mutations: ________ chromosomal mutations and ___________.

• Gene mutations: Point mutation- a change in a – ______ single base pair in DNA. This would result in a different codon and a completely different amino acid in the chain.

– ______ Frameshift mutation- a single base pair is added or deleted, resulting in a shift in the sequence. This results in amino acid changes from the point of the shift on, because if shifts the reading of the codons by one base pair.

• Chromosomal mutations can division happen during cell _______. Often, parts of the chromosomes are broken off and lost, or they break and rejoin incorrectly, or join to the wrong chromosome altogether.

Deletion – _____part of a chromosome is left out. – Insertion _____- part of a chromosome breaks off and rejoins to the sister chromatid, causing a duplication of a gene on the same chromosome. – Inversion- part of a chromosome breaks off and is reinserted backwards _____.