DNA and GENES

DNA Deoxyribonucleic acid (DNA) is made of __________________. Remember that nucleotides are made of three parts: ___________________________________________________________________________________________________ nucleotides a 5-carbon sugar, a phosphate group, and a nitrogen base

DNA The nucleotides that make up DNA contain the sugar ___________ and one of four different nitrogen bases: __________________________________________________________________ deoxyribose adenine (A), thymine (T), guanine (G), or cytosine (C).

DNA In 1953, scientists ________________________________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: ________________________________ James Watson and Francis Crick A with T and C with G

DNA 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 T A A C G C A T C G A C T A G

DNA Watson and Crick also discovered that DNA is twisted in a shape called a ______ _____. DNA looks like a twisted ladder. double helix

DNA The ______________ make up the “rungs” of the ladder. And the sugar and phosphate make up the “sides” of the ladder. This is called the ____________________________. base pairs sugar-phosphate backbone

DNA DNA carries the code for proteins. Proteins guide all cell and body chemistry.

DNA Proteins are made from strands of ____________, so DNA actually codes for specific amino acids and the _________________ assemble them to make proteins. amino acids ribosomes

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

DNA Replication

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

DNA Replication An enzyme called _____________ breaks the bonds between the nitrogen bases and the two strands of DNA unwind and separate. helicase

DNA Replication complimentary base 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 ______________ _____. (A-T and C-G) complimentary base

DNA Replication The sugar and phosphate parts of the free nucleotides bond together forming a backbone for the ________________________________. new strand of DNA

DNA Replication 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

RNA

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

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

Transcription

Transcription DNA stays in the _________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 called ____________________. nucleus transcription

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

Transcription c. Once the RNA copy is made it breaks away from the DNA and the DNA _______________________________. d. The new strand of RNA leaves the nucleus and takes its information into the _________ and to the ribosome. bonds back together cytoplasm

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

Transcription RNA has many responsibilities in the cell. There are three types of RNA _________________ RNA (mRNA)- made during transcription; delivers amino acid codes to the ribosomes Messenger

Transcription Ribosomal _________________ RNA (rRNA)- makes up ribosomes; reads codons

Transcription Transfer _________________ RNA (tRNA)- transfers amino acids to ribosomes

Transcription Every sequence of three nitrogen bases in mRNA is called a ___________. EX: AUC, UUU, GCA These different codons hold information to make specific amino acids. Since there are four bases, ____ different codon combinations are possible. codon 64

Transcription These 64 combinations make up the codes for the ________ different amino acids. The mRNA genetic code is on p.298 in your book. Learn how to read it. twenty

Transcription anticodon An _____________ is a nitrogen base sequence that is the opposite of the original codon. It is found on tRNA and has the corresponding __________________ for the codon attached to it. amino acid

Transcription Write the correct anticodon and amino acid for the following codons: CUG- AAG- GCU- UUC-

Translation

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

Translation Once the mRNA has attached to the ribosome, tRNA binds to the ______ _______ (always AUG) and begins forming a chain of amino acids. start codon

Translation b. As the mRNA is being read, it slides through the ribosome. A new _________ attaches at every codon, bonding its amino acid to the previous and then it falls off. tRNA

Translation c. The newly formed protein falls off when the ribosome reads the _____________. stop codon

Mutations

Mutations 2. Sometimes there are mistakes in the DNA sequence that may affect the genetic information passed to offspring. This is called a ____________. mutation

Mutations Some mutations are small and undetected, but some may cause problems.

Mutations 2. Things that cause mutations in DNA are called __________. Some examples are X rays, UV light, and radioactive substances. mutagens

chromosomal mutations. There are two different types of mutations: _________________________ and ____________________________. gene mutations chromosomal mutations.

Mutations Gene mutations (p.304 Figure 11.10):

Mutations ________ 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. Point

Mutations a. _____________ 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 it shifts the reading of the codons by one base pair. Frameshift

Mutations mitosis or meiosis 7. Chromosomal mutations can happen during ____________________. Often, parts of the chromosomes are broken off and lost, or they break and rejoin incorrectly, or join to the wrong chromosome altogether. mitosis or meiosis

Mutations a. ____________- part of a chromosome is left out. Deletion

Mutations b. ____________- part of a chromosome breaks off and rejoins to the sister chromatid, causing a duplication of a gene on the same chromosome. Insertion

Mutations c. Inversion- part of a chromosome breaks off and is reinserted __________. backwards

Mutations d. Translocation- part of a chromosome breaks off and is added to another chromosome.

Mutations e. _________________- chromosomes do not separate correctly and offspring ends up with too many or too few chromosomes. This causes birth defects. Nondisjunction