Study Guide Chapter 12

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1 Study Guide Chapter Know ALL of your vocabulary words! 2. Name the following scientists with their contributions to Discovering DNA: a. Strains can be transformed (or changed) into other forms while studying bacteria that cause pneumonia. Discovered transforming factor could change bacteria into other forms of bacteria. Griffith b. Identified the specific molecule that transformed the rough strain of bacteria into a smooth strand of bacteria. Discovered that DNA is the transforming factor. Avery c. Used radioactive labeling when studying viruses and bacteria and discovered that DNA is the genetic material in a virus and not protein. Hershey and Chase d. Discovered the structure of DNA as being a double helix molecule. Watson and Crick

2 3. Compare/contrast DNA and RNA in the following table: Name Macromolecule Type Structure (single or double) Building Blocks Name of Sugar Phosphate? (Yes or No) 4 Nitrogen Bases DNA Deoxyribonucleic acid nucleic acid double nucleotides deoxyribose yes A T C G RNA ribonucleic acid nucleic acid single nucleotides ribose yes A U C G Leave Nucleus? (Yes or No) No Yes 4. What 3 organelles contain DNA? nucleus, mitochondria and chloroplast 5. Explain why the structure of DNA is referred to as a double helix molecule. Two twisted strands connected like a spiral staircase 6. Draw the basic structure of a nucleotide and label the parts (phosphate group, sugar, nitrogen base).

3 7. How and where are phosphate and sugar arranged on the DNA molecule? They alternate along the outside edges (rails) of the DNA 8. Where are the nitrogen bases found on the DNA molecule? they are paired in the middle (complementary) 9. What is meant by semiconservative replication? the old DNA separates, serves as a template, and then becomes part of the new DNA 10. Semiconservative replication is the process of copying DNA. Explain the 3 steps of this process. a. Step 1: Unwind and unzip the DNA What enzyme unwinds and unzips the DNA into two separate strands? DNA helicase What happens to the hydrogen bonds between base pairs? The bonds are broken Which molecule is responsible for keeping the DNA strands open and separate? single strand binding proteins What enzyme adds short segments of primer on each DNA strand? Primase

4 b. Step 2: Add new base pairs What is the function of the enzyme DNA polymerase? add the new nucleotides to make the new DNA (T/F) The two new strands of DNA are being produced in the same way. 1. The (leading, lagging) strand adds new nucleotides in a smooth, continuous motion. 2. The (leading, lagging) strand adds new nucleotides in small chunks called Okazaki Fragments and the motion is discontinuous. «What enzyme is responsible for adding more bases to fill in the gaps to make a continuous DNA strand? DNA ligase c. Step 3: Joining the base pairs DNA polymerase removes primer and fills in the place with nucleotides. DNA ligase joins the sections to make each strand continuous. How many new strands of DNA are produced at the end of replication? 2 (T/F) Each new strand of DNA produced is made up of ½ old DNA and ½ New DNA.

5 11. Compare and contrast DNA replication in Prokaryotes and Eukaryotes. Prokaryotes DNA is shorter; DNA is in a circular shape; DNA replicates one section at a time BOTH replicate in two directions Eukaryotes DNA is longer; DNA replicates many sections at a time 12. According to the Base Pair Rule, what nitrogen bases pair together ALWAYS: DNA Adenine and Thymine Guanine and Cytosine RNA Adenine and Uracil Guanine and Cytosine 13. Which nitrogen bases are: Purines? A and G Pyrimidines? T C and U 14. (T/F) Purines always bind to pyrimidines. 15. How many hydrogen bonds between adenine and thymine (or uracil)? 2 (double bond) 16. How many hydrogen bonds between guanine and cytosine? 3 (triple bond)

6 17. (T/F) The two sides of DNA are oriented in opposite directions called anti parallel. 18. Explain how the DNA molecule (as long as it is) fits into a very small, microscopic cell. DNA coils around histones (proteins) to form chromatin. Chromatin coils to form nucleosomes. Nucleosomes supercoil and form X-shaped chromosomes 19. Why is DNA called the code of life or the genetic code? (Hint: What does it code for that is so important?) It codes for all of the proteins an organism needs to survive 20. Why are proteins important? Which 2 cell organelles synthesize proteins? Proteins determine how an organism looks and functions. Ribosomes and the Rough ER synthesize proteins 21. A segment of DNA that contains instructions for making a protein is called a. gene 22. (T/F) A gene is a specific location on a chromosome and controls inherited trait expression when passed on for generations.

7 23. Name and describe the functions of the 3 types of RNA. mrna - messenger RNA the complementary strand to DNA. Carries the "recipe" to the ribosome rrna - ribosomal RNA forms the structure of the ribosome trna - transfer RNA transports amino acids to the ribosome 24. Explain the process of transcription. a. Occurs in the nucleus protein b. A gene for a specific is turned on and copied from DNA into. c. As DNA strand unwinds and unzips the enzyme mrna RNA polymerase regulates RNA synthesis. d. What happens to the newly synthesized mrna strand and where does it go? it detaches from the DNA and migrates out of the nucleus into the cytoplasm. e. Two DNA strands. rejoin

8 25. How is DNA different among organisms? the sequence of bases is different 26. How many amino acids are used to make proteins? there are 20 total amino acids codon base code of nitrogen bases is called a. 28. (T/F) 1 codon codes for 1 amino acid.

9 29. Explain the process of translation. a. Occurs in the. cytoplasm b. Interprets genetic information from mrna and builds a. protein c. What attaches to a ribosome and how is it read? mrna attaches. It is read 3 bases at a time (codons) d. What does trna carry and drop off to the ribosome? How many different types of trna molecules exist? The end of the trna molecule where 3 complementary bases attach is called the. anti-codon The other end of the trna molecule is where an amino acid attaches. e. What type of bond forms between amino acids? peptide bonds f. What happens once the stop codon is reached? amino acids synthesis ends and the protein leaves the ribosome The ability of an organism to control which genes are transcribed is called. gene regulation 31. What is a mutation? permanent change in the DNA 32. (T/F) Mutations can affect a single gene or an entire group of genes 33. If a [gamete (sex cell), body cell (somatic)] becomes mutated, the mutation will be passed to offspring 34. If a [gamete (sex cell), body cell (somatic)] becomes mutated, the mutation will not be passed to offspring. 35. A chemical change in one base pair is called point mutation. a. Name and explain the 2 types of point mutation. missense = wrong amino acid will be added nonsense = an early STOP codon - the protein will be incomplete

10 36. A change in the frame of the amino acid sequence by adding or deleting nucleotides is called frameshift mutation. a. Name and explain the 2 types of frameshift mutation. deletion = a nucleotide has been lost insertion = an additional nucleotide is added to the sequence 37. A change which causes entire codons to repeat is called duplication mutation. 38. Give 2 factors that cause mutation to occur with DNA. DNA polymerase could add the wrong nucleotide Exposure to mutagens (radiation, chemicals, etc.) 39. (T/F) Mutations can cause proteins to function improperly or not at all.

DNA Replication & Protein Synthesis. This isn t a baaaaaaaddd chapter!!!

DNA Replication & Protein Synthesis This isn t a baaaaaaaddd chapter!!! The Discovery of DNA s Structure Watson and Crick s discovery of DNA s structure was based on almost fifty years of research by other