What’s Happening? Researchers have discovered a group of plant proteins that are related to the exocyst proteins in yeast [Plant Cell 20 (2008): 1330]. Explain how the following observations made by these researchers suggest that these plant proteins form a tethering complex similar to the exocyst complex of yeast and mammals.
(a) Following size fractionation of plant protein extracts, antibodies recognizing each of several different plant exocyst proteins bind to the same high-molecular-weight protein fraction.
(b) Mutations in four of the proteins each causes defective pollen germination.
(c) Plants lacking more than one of these proteins have more serious defects in pollen germination than plants lacking only one.
(d) The exocyst proteins all colocalize at the growing tip of elongating pollen cells.
(e) Pollen cells of plants with mutations in exocyst genes are defective in tip growth or germinating pollen cells.
Want to see the full answer?
Check out a sample textbook solutionChapter 12 Solutions
WORLD OF CELL+MASTERING ACCESS >CUSTOM
- Discuss Concepts In integrated pest management, a farmer uses a variety of tools to combat unwanted insects. These include applications of either hormones or hormone-inhibiting compounds to prevent insects from reproducing successfully. How might each of these hormone-based approaches disrupt reproduction?arrow_forwardApply Evolutionary Thinking The genes and proteins involved in cell cycle regulation in prokaryotes and eukaryotes are very different. However, both types of organisms use similar molecular regulatory reactions to coordinate DNA synthesis with cell division. What does this observation mean from an evolutionary perspective?arrow_forwardHello, I need help to draw mitosis cell for this type of plant, called Chrysopogon aciculatus which I believe reproduces through seeds. Attached is a picture of said plant under the microscope. However, I have trouble drawing its cell under mitosis(?). It is similar to onion root tip mitosis cells, but instwad of onion, it's this plant.arrow_forward
- A small amount if cytoplasm isolated from a mitotic cell is injected into an unfertilized frog oocyte, causing the oocyte to enter M phase. A sample of the injected cytoplasm is then taken and injected into a second oocyte, causing this cell also to enter the M phase. this process is repeated many times until essentially, none of the original protein samples remains, and yet, cytoplasm taken from the last in the series on injected oocytes is still able to trigger entry into the M phase with undiminished efficiency. Explain this remarkable observation.arrow_forwardThe BMP-Nodal gradient so vital to amphibian and fish development may be critically important in other vertebrates (including humans) as well. Moreover, can any field of pluripotent cells (such as human embryonic stem cells)respond to gradients of BMP and Nodal signals?arrow_forwardNeed answer of 4,5,6. Shortly plz 4.If the most basic function of the cell cycle is to duplicate accurately the DNA in the chromosomes and then distribute the copies precisely to the daughter cells, why are there gaps between S phase and M phase? 5. Describe the molecular mechanism of a CDK activation. 6. What is the cyclin-CDK complex in the M phase of the cell cycle?arrow_forward
- 13) A phosphotase removes an inhibitory phosphotyrosine phosphate from the serine protein kinase, in MPF whcih activates the kinase and triggers the initiation of mitosis. true or falsearrow_forwardVISUALIZE Label the following diagram and explain what this diagram illustrates.arrow_forwardVISUALIZE Sketch a roughly cuboidal cell preparing to divide. Indicate the orientation of the preprophase band and the site where the new cell walls of the daughter cells will form.arrow_forward
- Select the correct statement - - neural crest cells can differentiate into melanocytes, peripheral neurons, and epinephrine producing cells of adrenal glands -mice mutants in cascade genes die at birth due to insuffiencrt number of brain cells -yolk rich embryonic cells undergo hobovlastic cleavage -during cytokineses both animal cells and plant cells are separated by the contractile ringarrow_forwardACTIVITY 5: Sex-linked inheritance In many animals, the sex of an individual is determined by which sex chromosomes (X or Y) are inherited. In mammals (and the fruit fly Drosophila), females have 2 X chromosomes and males have one X and one Y. The X and Y are an unusual pair of homologous chromosomes. The X is large and contains thousands of genes, while the Y is small and contains few genes. Most genes on the X are not found on the Y, so males possess only one copy of each X-linked gene and females have 2 copies. This means that X-linked recessive traits are expressed more often in males. Eye color is a sex-linked trait in Drosophila. The allele for red eyes is dominant to the allele for white eyes. Because this gene is on the X chromosome, the alleles are written as XR and Xr. A. Do a Punnett square for a cross between a homozygous red-eyed female (XR XR ) and a white-eyed male (Xr Y). What would be the genotypes of the female…arrow_forwardPrompt Sometimes, changes or “mutations” occur that prevent genes from doing their job properly. Certain mutations in the BRCA genes make cells more likely to divide and change rapidly, which can lead to cancer. Given your understanding of meiosis and inheritance explain the following statement: “If either your mother or your father has a BRCA1 or BRCA2 gene mutation, you have a 50% chance of having the same gene mutation.”arrow_forward
- Biology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage LearningBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage Learning