Complete each sentence with the appropriate term. skeletal muscle tRNA genes varies from tissue to tissue is the same in all tissues transcribe electron transport chain homoplasmic translate different from the same as heteroplasmic brain Leber's hereditary optic neuropathy (LHON) results from mutations in mitochondrial genes. LHON symptoms are seen when optic nerve cells are homoplasmic for the disease mutation. Myoclonic epilepsy and ragged red fiber disease (MERRF) is caused by loss-of-function mutations in mitochondrial tRNA genes. People with MERRF are usually heteroplasmic because cells with only mutant mitochondria cannot translate mitochondrial mRNAs and die. The percentage of mutant mtDNAs in a mother's cells can be the percentage in her children's cells. Within one heteroplasmic person, the ratio of mutant to wild-type mtDNAs the same as. If the cells in a MERRF patient have 20% mutant mtDNAs, the tissue will not be affected. If the brain cells in a MERRF patient have 20% mutant mtDNAs, the tissue will be affected. Reset
Added by Gary A.
Close
Step 1
LHON results from mutations in mitochondrial genes: tRNA genes. Show moreā¦
Show all steps
Your feedback will help us improve your experience
Adi S and 96 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
DNA and Populations Worksheet (14pts) Name: A study on the variation of the Dark-eyed Junco (a small passerine bird species throughout its geographic range is summarized at right. The 4-letter codes (i.e. ORJU, WWJU, YEJU, etc.) in the figure correspond to named variants (subspecies) of the junco. Differences in plumage coloration are illustrated on the map part of the figure, and variation at one gene in pie charts to the right of the map. Numbers in the figure correspond to sites where the birds have been surveyed and sampled. 1. What scale best describes this study? a. ecosystems b. communities c. populations d. individuals 2. The map part of the figure illustrates the ____ variation of juncos. a. genotype b. phenotype c. species richness d. chromosome number 3. The pie charts on the right summarize the variation of... a. nucleotides within proteins of juncos. b. relative abundance of juncos at each site. c. ratio of alleles of a gene found in the DNA of juncos. d. number of chromosomes found in juncos. 4. Given the information presented in the figure, you would predict that... a. The YEJU populations are always more closely related to each other than to the WWJU population. b. The WWJU population lacks an allele found in the other junco populations. c. All Junco populations have the same number of chromosomes. d. All of the above are correct. e. None of the above are correct. 5. If we assume that the WWJU population has the original allele type, you would predict that... a. mutations in gamete cells produced another allele type in the rest of the junco populations. b. differential gene expression produced the rest of the variation of alleles in juncos. c. the Junco populations are always in Hardy-Weinberg equilibrium. d. All of the above are correct. e. None of the above are correct. 6. Suppose that the differences in junco plumage color are due to variation in the MCR gene located on an individual's chromosome nr.2 (birds are diploid). In the box at right, draw this diploid chromosome and indicate the location of the MCR gene in a heterozygous individual (you can name the two different alleles). 7. Select one of the Five Big Ideas in Biology and apply it in a sentence to the junco scenario.
Supreeta N.
Option B: Tay-Sachs disease is a disease that manifests in nerve and spinal cord malfunction in infants. It exhibits an autosomal recessive inheritance pattern. The disease results from a mutation in the Hexa gene located on the 15th chromosome. The Hexa gene encodes for a subunit of the hexosaminidase enzyme. The Hexa gene is large and can have many different mutations along the DNA. Thus, several different mutations could occur in the gene that will lead to the expression of the disease. The specific location of a mutation in the Hexa gene will affect if the mutation will cause the disease. Analyze the data provided and answer the questions to determine the genetic cause of the disease. Leah and Jenny are sisters. Leah is older and does not have Tay-Sachs disease. Jenny is three months old and starting to show signs of Tay-Sachs disease. There are five nucleotide differences between Leah and Jenny in the Hexa gene: Leah: 5ā-----TAG-------------------TTT----------GAT-----------AAA------------CCT 3ā-----ATC-------------------AAA----------CTA----------TTT----------- GGA Jenny: 5ā-----TGG------------------TCT-----------GAA------------AAT-----------CCC 3ā-----ACC------------------AGA-----------CTT------------TTA-----------GGG (affected) 1) At first glance, which DNA difference (one) can you immediately eliminate as causing Tay-Sachs in Jenny? Explain your answer in one sentence. 2) You take a closer look at the second genetic difference between Leah and Jenny. What kind of mutation is this called? 3) You take a closer look at the fifth difference. What kind of mutation is the fifth difference? Is it likely to be causing the disease? Explain why or why not in one sentence. 4) Itās possible that the first genetic difference affects which of the following: RNA polymerase, DNA polymerase, ribosome? 5) What kind of mutation is the third difference? 6) What does the structure of these two amino acids indicate about how likely it is that difference three is the causative site? 7) Based on your investigation, which nucleotide change is most likely to have resulted in Jenny developing Tay-Sachs? Please provide a thorough, 2-3 sentence explanation of the rationale behind your answer.
Josee P.
The peripheral nerves are formed from combinations of neurons whose origins are at different cord segments. The anatomical structure where this reorganization occurs is called a plexus. The cervical plexus is shown to the left: Locate the phrenic nerve [its fibers originate in ventral rami C3-C5. Using a pencil or pen, draw the pathways that fibers would follow from the ventral rami to the phrenic nerve. Segmental branches Hypoglossal nerve (XII) Ventral rami Lesser occipital nerve Greater auricular nerve Speculate on how the strength of the respiratory muscles would differ if the spinal cord were damaged between C4 and C5 and between C3 and C4. Transverse cutaneous nerve Accessory nerve Phrenic nerve Supraclavicular nerve Identify the remaining plexuses. For each plexus, identify peripheral nerves by name and describe the structures innervated by that nerve.
Adi S.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD