Structure Function Role in protein production (not all may relate directly to this)

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1 Genetics 2014 Semester 1 Final Exam Review Sheet Unit 1: Cells Structure and Function. Review Questions: 1. What is the function of the following cell structures? Structure Function Role in protein production (not all may relate directly to this) Nucleus Control Center of the Cell Holds the master copy DNA for how to make a protein Endoplasmic reticulum Modifies the Protein Shape Folds the protein after initial assembly by the ribosome Ribosome Makes the Proteins Makes the primary structure Golgi apparatus Lysosome Packages and ships materials out of the cell Break down excess fats and proteins. Gets rid of foreign particles Ships the finalized protein out of the cell. N/A Mitochondria Produce ATP N/A lysosomes Peroxisomes Break down peroxides N/A Cilia and flagella Aid in movement of the cell N/A Unit 2: Organisms progress through a series of stages as they grow and develop. Review Questions: 1. What trimester are the effects of a teratogen most likely to cause harm to the embryo? First Trimester (9 weeks) 2. Can a teratogen be found in the diet of a mother? Yes 3. What are some examples of teratogens? Alcohol, Stress, Drug use, Malnutrition, etc. 1

2 4. Must a teratogen pass through the placental barrier to cause harm to a baby? NO 5. Would maternal stress be considered teratogenic to a baby? Yes, causes behavioral problems and low birth weight. 6. For a male to pass a birth defect on to his offspring, what type of cells would have to be infected? Spermatogonia 7. Fill out the following chart. Exposure source Symptoms in developing fetus at 20 weeks Alcohol Smal head/ flat face/ widely spaced eyes/ short nose 8. What factor greatly increases the risk of an abnormal chromosome number in the fetus? Age of the mother 9. Compare the two types of cell division. Mitosis Meiosis Occurs in body cells Yes N Occurs in sex cells N Yes Results in 2 identical cells Yes N Results in 4 non-identical cells N Yes Tetrads form N Yes Sperm form N Yes Haploid cells result N Yes Results in diploid cells Yes N Crossing over occurs N Yes 10. Draw the cell cycle and label the following. G1, G2, S, Interphase, prophase, metaphase, telophase, anaphase, M phase. Circle the stages in which the volume of DNA would be doubled. S, G2, prophase, metaphase, anaphase, telophase 2

3 11. You observe 200 cells under the microscope and you observe 100 in interphase, 30 in prophase, 20 in metaphase, 22 in anaphase, and 28 in telophase. What is the mitotic index? (mitotic index = number of cells in mitosis/ total number of cells) Mitotic index= / /200=0.50 or 50% 12. The Cytoskeleton is made up of microtubules. During mitosis the mitotic spindle is made up of microtubules that attach to the chromosomes and move them to each end of the cell. 13. What is the difference in the growth rate between cancer cells and normal cells? Cancer cells will continue to reproduce even when they are touching one another. This continued division eventually causes a tumor. 14. Draw an animal cell with 8 chromosomes as it moves through the phases of mitosis. 15. What is the difference between a pluripotent cell and a totipotent cell? Totipotent stem cells retain the ability to become any type of cell in the body. Later in development Pluripotent stem cells form and they can only become certain types of cells. 16. What is the difference between a germ cell and a somatic cell? Germ cells: Reproductive cells Somatic Cells: Body Cells 17. What is the difference between a fetus and an embryo? A developing human is considered an embryo in the first 8-9 weeks of development. A Fetus is more developed and has the basic organs and structures that will make up the mature baby at birth. 3

4 18. List the functions of the male reproductive system in the table below. Structure Testes Seminal Vesicles (change) Vas deferens epidiymus Bulbouretra prostate Function Produce the sperm in the seminal vesicles Provide energy to the sperm Provide a duct for the sperm to travel from the testes to the urethra Sac above the testes that stores sperm as they mature Lubricates the urethra Activates the sperm to start swimming. 19. List the functions of the female reproductive system in the table below. Structure Fallopian tube/oviduct Ovary Uterus Follicle Function Provides a duct for the Egg to travel from the ovary to the uterus Produces the Oocytes Provides a stable environment for the developing embryo Fluid filled sac that contains an oocyte 20. How many different combinations of chromosomes can be packaged in gametes made by an organism with a diploid number of 12 (2n=12)? Use this formula: (2 n, where n = the haploid number.) 2 6 = 64 different combinations 21. Fill in the following chart for diploid and haploid number of chromosomes. Diploid # of chromosomes Somatic Body cells Haploid # of chromosomes Gametes (or sex or reproductive cells) Egg or Sperm

5 22. Fill in the following chart on development. Stage Cleavage Blastocyst gastrula Neural tube development Principal Events The zygote goes through a series of quick divisions Hollow ball of cells, with an inner cell mass that will be the embryo The blastula folds in on itself forming the 3 germ layers Beginning of the CNS 23. After the egg has been fertilized, all resulting cells are (Somatic, Germ) and arise through (mitosis, meiosis) Unit 3: Traits in living things are encoded in molecules of DNA. Review Questions: 1. What are the building blocks of DNA? Nucleotides 2. What makes up a DNA nucleotide? Deoxyribose, phosphate group, nitrogen base 3. Draw a picture of the electrophoresis chamber with a gel inside the chamber. Identify and state the role of the following in your diagram. negative and positive electrode wells in the gel fragments of DNA power source draw an arrow indicating the path that DNA will follow as it flows through the gel 4. In gel electrophoresis what is the relationship between the size of the fragments and the distance they will travel in the gel? The farther it travels the smaller the fragment. 5. If a mutation occurred in which Aspartic Acid was substituted for Alanine (which is normally found in the protein) what type of mutation was this? What base was specifically changed in Aspartic Acid? Point mutation/substitution GCC or GCU was replaced with GAC or GAU 5

6 6. If 22% of the bases in DNA were Adenine, basing your answer on Chargaff s rules, what would be the percentages of the other bases in DNA? a. Thymine = 22% b. Cytosine = 28% c. Guanine = 28% 7. What is the role of each of the following in DNA replication? a. Helicase: Separates the two DNA strands b. Single-strand binding protein: Helps keep the 2 strands from coming back together. c. Primase: Adds a primer for DNA polymerase to attach d. DNA polymerase: Adds nucleotides forming the complementary strand e. Ligase: Seals the breaks in the okazaki fragments. 8. How is replication different on the leading and lagging strands? On the leading strand it is continuous in a 5 to 3 direction. On the lagging strand it starts and stops as helicase unwinds the DNA. 9. DNA replication is considered to be (Conservative, Semiconservative) meaning that each cell will have 1 original strand and 1 copied strand. Unit 4: Proteins are synthesized from genes and have a specific structure and function in organisms. Review Questions: 1. Describe the relationship between DNA, RNA, and protein. DNA found in the nucleus is transcribed into mrna The mrna moves out to the cytoplasm and binds to a ribosome where it is translated into a protein. **Remember protein shape determines function** 6

7 2. Look at the diagram below and label the following. Explain what each step is in protein synthesis. DNA, codon, amino acid, polypeptide, mrna, transcription, translation 3. How many nucleotides make up a codon? 3 4. How many codons code for an amino acid? What is the role of trna in translation? It attaches to an amino acid and brings it into the ribosome, thus assembling the protein. 6. What is an anticodon? How many trna anticodons would be needed to make the polypeptide shown above? Part of trna w/ 3 bases complementary to mrna codon; 4 7. Fill in the flow chart using the following terms. Then answer the questions that follow. Terms: DNA, RNA, polypeptides, enzymes, cell parts 7

8 A. DNA, B. RNA, C. polypeptides, e. enzymes Questions: What part of the flowchart would take place in the nucleus? A, B What part of that flowchart would take place in the cytoplasm? C Where would you place DNA replication in this diagram? A Where is transcription and translation occurring? A B; C 8. The following is a sequence of mrna codons. UUU-CGA-GGA-CGU-AAA a. What is the DNA sequence this was coded from? AAA-GCT-CCT-GCA-TTT b. What is the anticodon sequence that will be made from this strand? AAA-GCU-CCU-GCA-UUU c. What is the amino acid sequence that will be made from this strand? Phenylalanine-Arginine-Glycine-Arginine-Lysine 7. Predict what affect a mutation would have on gene expression if there was a mutation in gene cluster 2 on the diagram above. Enzyme 1 would accumulate, and no citrulline or Arginine will be produced 8. Draw a protein that shows 4 levels of conformation. (primary, secondary, tertiary, quarternary) 8

9 9. Describe the differences between DNA separated by gel electrophoresis and protein separated by gel electrophoresis by filling in the chart below. DNA gel electrophoresis What is being separated DNA Proteins Protein electrophoresis Type of gel used Agarose Acrylamide How can you tell the difference between the two? The bands are much tighter and closer together 10. How can you tell if a specific band in a gel has a lot of protein or very little protein. It is darker. Unit 5: A cell transcribes and translates only a subset of its genome. 1. What is the difference between a hydrophillic amino acid and a hydrophobic amino acid? Hydrophillic are attracted to water (outside), hydrophobic are repelled by water( Inside) 2. What affect would a mutation have that changes a hydrophobic amino acid to be replaced by a hydrophillic amino acid? It would change the tertiary structure, thus its shape and function. 3. Explain how gene expression is affected by acetylation and methylation. Acetylation allows genes to be expressed by allowing the DNA to move away from the histone. Methylation turns off gene expression my attaching methyl groups to the DNA 4. What is differential gene expression? Where cells of the same basic type can produce different proteins, since some genes are turned on and some genes are turned off. 5. What do researchers use RNAi for? Block gene expression 9

10 6. What happens in excision repair? DNA damaged by UV light for example can be repaired, thus preventing a mutation or cancer. 9. Fill out the chart below regarding mutation types. In the sequence change column give an example of how the mutation might show up in the mrna sequence. The following is the normal mrna sequence. AUG- AAG-CCC GGC AAA (Normal, no mutation) Type of mutation Sequence change Explanation Insertion AUG-AAG-CCC-CCC-GGC-AAA A complete codon was inserted into sequence causing an additional amino acid to be added Point mutationsubstitution AUC-AAG A single nucleotide was switched out. Frameshift mutation AUU-GAA-GCC Insertion: effects all amino acids after the mutation Missense mutation AUG-CAG 1 amino acid is changed Nonsense mutation AUG-UAG Changed to a stop codon Transitional mutation AUG-AAA Purine for purine Transversion mutation AUG-AAC Pyrimidine for purine 10

11 J = a Repressor that shuts down gene expression. A, B, and C = structural genes 9. If the repressor remains attached to the operator, what effect will this have on A, B, and C? Structural Genes A, B, and C will not be transcribed 11