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Biology Review Guide
Unit 7 DNA Review Guide
Question | Answer |
---|---|
Describe how each of the following scientist contributed to our current understanding of DNA: Griffith | Griffith discovered DNA, the "transforming principle". |
Describe how each of the following scientist contributed to our current understanding of DNA: Franklin & Wilkins | Franklin & Wilkins used x-ray crystallography to visualize DNA |
Describe how each of the following scientist contributed to our current understanding of DNA: Watson & Crick | Watson & Crick came up with the double-helix structure of DNA |
Describe the central dogma of biology. | DNA is the code that has all the information an organism needs to form its structure and carry out its functions. |
Describe the central dogma of biology including how transcription and translation fit in. | Through transcription, DNA is used to make RNA, the form that ribosomes can read. Through translation, RNA is used to make proteins, which form our body structure and carry out its functions. |
What causes mutations in DNA or RNA? How do these mutations affect proteins? | Mutations are caused by an error in the process of replication or transcription. This error will cause a different protein to be made, or for it to work incorrectly. |
What is the function of DNA & genes in relation to proteins? | A gene is a section of DNA that codes for one protein. |
Describe the stucture of a DNA nucleotide. | Each nucleotide has 3 parts: sugar, phosphate, base The base can be adenine (A), thymine (T), guanine (G), or cytosine (C). |
Recall Chargraff's rules: What does Chargraff's rule tell us about the amount of each base in DNA? | amount of A = amount of T amount of G = amount of C |
Use Chargraff's rule to determine the amount of each base in an organism containing 18% adenosine (A). | 18% thymine + 32% guanine + 32% cytosine + 18% adenosine = 100% |
How is hydrogen bonding related to the double helix structure? | Hydrogen bonds are not as strong as covalent bonds. This gives DNA enough flexibility to bend into the double-helix structure without breaking. |
What causes certain bases to be "complementary"? | Complimentary bases have opposite changes and the same number of locations to bond. |
List complementary base pairs of DNA. | C=G A=T |
List the 3 major enzymes involved in DNA replication and describe their role: (1st enzyme) | helicase : unwinds DNA by breaking hydrogen bonds between base pairs. |
List the 3 major enzymes involved in DNA replication and describe their role: (2nd enzyme) | DNA polymerase: adds on new nucleotides of DNA, forming new nucleotides between base pairs. |
List the 3 major enzymes involved in DNA replication and describe their role: (3rd enzyme) | ligase: seals up DNA by forming covalent bonds between sugar & phosphate. |
Under what circumstances does DNA replication occur? | DNA replication always occurs before cells divide. Cells divide for growth and repair. Therefore, DNA replication occurs when an organism needs to grow or repair itself. |
Describe structural differences between DNA and RNA. | DNA is double stranded, RNA is single stranded. DNA has the base thymine. RNA has the base uracil instead. |
In general, what is the role of RNA? | RNA is the form of nucleic acid that can be transported out of the nucleus and read by ribosomes to make proteins. |
List 3 types of RNA, their shapes, and what they do. | mRNA = single strand, carries genetic info from nucleus to ribosomes. tRNA=hairpin shape, transfers amino acids o ribosomes to make proteins. rRNA=glob shaped, make up ribosomes, the location where proteins are made. |
Describe the process of translation using the following terms: codon, amino acid, protein, start codon, stop codon. | A start codon starts the process. Every 3 bases is a codon for 1 amino acid. Amino acids will form a chain that is the basis of proteins. The stop codon stops the process of translation. |
Explain the process of a polymerase chain reaction. | The desired gene is isolated. A DIVA primer is used to start the replication process. Taq polymerase is used to add nucleotides to the gene. |
Describe the process of gel electrophoresis and how it can be used to analyze DNA fingerprints. | A current is run through gel. DNA fragments of different sizes will each travel certain distances down the gel, depending on their size. Each person has unique DNA, so a different pattern will show up based on the fragments of DNA they have. |