Browsing by Subject "Biologian opettaja"

Sort by: Order: Results:

Now showing items 1-9 of 9
  • Nykänen, Sonja (Helsingin yliopisto, 2019)
    Colorectal cancer (CRC) kills more than half a million people a year worldwide. Usually the disease develops over several years via multiple steps which involve both genetic and epigenetic alterations. CRC is often diagnosed at late stage, when the cancer has already metastasized, and the prognosis is relatively poor. Several studies suggest that the first changes towards colorectal cancer occur and can be detected in histologically normal tissue before the appearance of any detectable lesion. The precancerous cells harbouring those changes may form a field of tissue, which is predisposed to malignant transformation. The study of pre-cancerous tissue might reveal the earliest changes in CRC development, which can be used as biomarkers for early detection and prevention of CRC. The aim of this thesis was to revise and investigate whether the aberrant expression of the six chromosomal segregation genes, Bub1, Mis18a, Pms2, Rad9a, Tpx2, and Mlh1, would signal carcinogenesis in mouse colon mucosa. Altogether fourteen mice, of which six had a proximal colon carcinoma, were selected for the study. The expression analysis was performed to histologically normal colon mucosa collected from the proximal and distal colon of each mice in order to investigate whether the possible pre-cancerous changes are found exclusively in the close proximity to the carcinoma. The expression was quantified with reverse transcription quantitative polymerase chain reaction (RTqPCR). No statistically significant gene expression differences were found between the carcinoma and control mice, indicating that the studied mice did not display cancer-preceding expression changes of the six studied genes in the carcinoma adjacent histologically normal colon mucosa. The results differed from the previously reported results, where the expressions of the six genes were found to be downregulated in the carcinoma adjacent mucosa. Here, the sample size was presumably not large enough to reveal statistically significant clustering of the expression patterns. However, Bub1 seemed to have a downregulated trend in the carcinoma adjacent mucosa, which supports the previously suggested role of Bub1 alterations in CRC initiation.
  • Mantela, Fanni (Helsingin yliopisto, 2021)
    There are no comprehensive research data on Finnish matriculation examinations in biology. This type of data is needed, because evaluation guides what and how students learn and what they consider important. Genetics is one the most challenging topics in biology, and in the opinion of teachers it will continue to be an important discipline in the future. The importance of studying genetics can also be justified with philosophical, social and health reasons. This is why the present study focused on the genetics component of the matriculation exam in biology. The aim of the study was to provide information on the challenges and contents of past matriculation examinations in biology and how they have aligned with high school curricula. The results of the study could be used to evaluate this alignment in relation to genetics questions in the biology exam, and could help in designing new matriculation examinations that align better with the existing high or new high school curricula and their aims. The research questions were: 1. What knowledge and cognitive dimensions are measured with the genetics-related questions in matriculation examinations in biology? 2. How do knowledge and cognitive dimensions in genetics-related questions in biology matriculation examinations relate to high school curriculum aims? The data comprised matriculation examination papers in biology from spring 2011 to autumn 2020 (20 exams) and the aims of the Finnish national High School Curriculum in 2003 and in 2015. Qualitative content analysis was performed on the knowledge dimensions (factual, conceptual or procedural knowledge) and the cognitive process dimensions (remembering, understanding, applying, analyzing, evaluating or creating). The basis of this qualitative content analysis was Bloom’s revised taxonomy. The analysis was conducted on genetics-related matriculation examination questions and on the aims of the high school curriculum. The test questions and the aims were compared to determine whether they aligned. Classified questions were divided into two subcategories depending on which high school curricula they corresponded to. Genetics-related questions from spring 2011 to autumn 2017 corresponded to the High School Curriculum in 2003 and questions from spring 2018 to autumn 2020 corresponded to the High School Curriculum in 2015. Questions from the previous period were divided into all knowledge dimensions. All questions, except one, incorporated lower cognitive dimensions (remembering, understanding and applying). The main combined class was understanding conceptual knowledge. Questions from the later time period were also divided into all knowledge dimensions. Mostly lower cognitive dimensions were incorporated into the questions, but a few subquestions addressed higher cognitive dimensions (analyzing, evaluating and creating). The main combined class was understanding conceptual knowledge. All the aims were classified into conceptual or procedural knowledge classes. The aims were also divided between all cognitive dimensions, except remembering. Using constructive alignment as the basis for matching aims with questions, two aims in the High School Curriculum of 2003 and six aims in the High School Curriculum of 2015 had no questions that matched them. These aims mostly measured the cognitive dimension of creating. Several aims appeared to incorporate higher cognitive dimensions, but the questions were less well aligned with the aims than with those incorporating lower cognitive dimensions. The results concerning knowledge and cognitive dimensions were mostly as expected. Lower cognitive dimensions were highlighted in genetics-related matriculation examination questions in biology. The challenge of interpretation brought ambiguity to the aims and cumulative levels of cognitive dimensions when aligning questions with aims, as some of the questions aligned with aims did not assess such high cognitive dimensions as would be expected based on the aims, but were nonetheless aligned with them. Furthermore, there may be several reasons behind the absence of the creating dimension in matriculation examination questions. The alignment of questions and aims would be important to consider in the future, because evaluation has a considerable impact on studying.
  • Björn, Marko (Helsingin yliopisto, 2021)
    Abstract: The EEG measurement protocol is standardized and in use globally. The skull is measured to ensure that the electrodes are placed in the correct position. Measurements are necessary because skull sizes and shapes are different. Studies for placing electroencephalograph (EEG) electrodes on a human head are typically introduced theoretically before students are granted the opportunity to practice. Due to the limited availability of EEG equipment and supervisory staff, students encounter shortened practical training sessions and lengthy waiting periods transitioning from theory to practical components. The main aim of this project was to create a learning environment with game technologies to help students study electrode placement during the idle time between theory lessons and practical training. We set out to determine whether students experienced some learning gain and if they had a positive experience with the learning environment. We simultaneously assessed if fuzzy feedback is preferred over exact feedback. Additionally, the aim was to make use of a design-based approach with the information from a User Experience Questionnaire (UEQ) the EEG-simulator. Our group developed and tested a digital learning application that provides a 3D model of a human head, on which learners can practice placing EEG electrodes. We followed a user-centric design science approach to ensure our application appeals to our target audience. We used an observational post-test only design with two experimental groups and a control group. We applied a widely accepted user experience questionnaire to ascertain which of our two feedback systems elicited the best user experience. We also qualitatively analyzed diaries the students kept, as they worked with the learning environment, to better understand future development options for further maximizing the environment’s learning benefit. The overall application was well-received, and students opined that the application significantly enhanced their practical session experience. Although the post-test evaluation showed no difference between the two experimental groups, the user experience questionnaire showed that the fuzzy feedback system was preferred over the exact feedback. Furthermore, it was evident that students who had not used the learning environment struggled more to come to terms with the practical session. The personal experience recording by the students revealed several suggested improvements to the learning environment. We conclude that, with further development, this EEG placement learning application could address the idle period between demonstration lessons and practical training. We also venture to state that fuzzy feedback is preferred because of the high-fidelity mimicry of real teacher feedback. The last part of the research was to develop the EEG simulator so that it will increase theory learning with a simulator, that works, and this is ongoing. We have developed the last EEG simulator version with AR (augmented reality) mobile version that can be used with any smart devices. The future work is to test EEG application and does application influence student's theory learning process.
  • Kiviluoma, Tomi (Helsingin yliopisto, 2021)
    Education research has for decades acknowledged that prior knowledge is a strong predictor of academic success. This idea is largely based on constructivist theory of learning which postulates that all learning occurs by actively building on existing knowledge. When this prior knowledge conflicts with the normative scientific understanding, students are dealing with incompatible knowledge structures, or misconceptions. Misconceptions need to be revised and sometimes even replaced through a learning process called conceptual change. Research shows that the level of prior knowledge can determine students’ academic success and performance. Undergraduate biology students enrol to university with diverse levels of prior knowledge and concepts regarding topics such as photosynthesis, cellular respiration, primary production in ecosystems, and Darwinian evolution. These topics present challenges for learning because of their complexity. At the same time, a robust understanding of them is essential. These topics are at the heart of mitigating and resolving the climate crisis and other global natural threats. This study explored the level of prior knowledge and the nature of misconceptions held by undergraduate biology students at the beginning of their academic degree in fall of 2019, and further sought to describe how their conceptual understanding developed during the first academic year. Students (N = 41) completed a questionnaire consisting of eight open-ended questions that were designed to assess declarative knowledge of facts and meaning, and procedural integration and application of knowledge. This pre-test measurement was conducted in September 2019. In the post-test measurement, the same questionnaire was repeated a year later. The data were analysed with a mixed methods approach where the answers were quantitatively scored as well as qualitatively analysed for misconceptions. The qualitative content analysis of the answers relied both on existing literature and on the content of the answers themselves. Results showed that the students’ prior knowledge was relatively poor in the beginning of their studies. Most students performed well in tasks measuring knowledge of facts and meaning but struggled in tasks measuring integration and application of knowledge. During the first academic year, the students’ understanding generally improved as demonstrated by the improvement in mean scores of the tasks. Misconceptions were robust and pervasive. The most pervasive misconceptions reflected difficulties in understanding emergent properties and processes. Misconceptions related to the process of Darwinian evolution became more prominent in the post-test. Persistent misconceptions became integrated with the new conceptual frameworks that the students acquired during the first academic year. If students held no misconceptions in the post-test, they performed significantly better in both tests than those with misconceptions. During this first academic year learning seemed to be mainly additive as conceptual change turned out to be rare. The need for more encompassing biology teaching at least in the University of Helsinki became evident. Introductory courses should acknowledge the large degree of variation in students’ prior knowledge and assess the most common and serious misconceptions even over course theme disciplines to ensure more equal learning outcomes.
  • Luoto, Senni (Helsingin yliopisto, 2021)
    Kalvojännitteen syntyyn ja sen muutoksiin liittyvät prosessit mielletään usein haastaviksi aiheiksi oppia ja opettaa. Aiheen opetuksesta ja oppimisesta lukiossa ei juurikaan ole tehty tutkimusta, mutta aiemmat tutkimukset yliopisto-opiskelijoilla ovat osoittaneet, että haasteita esiintyy erityisesti lepokalvojännitteen muodostumisen ymmärtämisessä. Aihetta käsitellään suomalaisissa lukiossa pääasiassa ihmisen biologian kontekstissa vapaavalintaisella kurssilla 4 (LOPS 2015) tai 5 (LOPS 2019) ja aihe onkin yksi ihmisen biologian kurssin keskeisistä sisällöistä oppia ja ymmärtää. Kalvojännitteen synty ja sen muutokset on kuvattu suomenkielisissä lukion biologian oppikirjoissa usein yksinkertais-tetusti ja ajoittain virheellisesti. Tämä saattaa johtaa virhekäsitysten syntymiseen, jolloin opiskeltavaa aihetta ei opita riittävällä tasolla. Siksi tämän maisterintutkielman tavoitteena on selvittää, miten solukalvon sähköistä aktiivisuutta opetetaan suomenkielisissä lukioissa ja millaisia virhekäsityksiä opiskelijoilla aiheesta esiintyy. Näiden tulosten pohjal-ta luodaan kehittämistuotos eli opetusmateriaali biologian aineenopettajien käyttöön, jolla voidaan tukea solukalvon sähköisen aktiivisuuden opetusta ja oppimista. Tutkimusmenetelmänä tutkimuksessa käytettiin kehittämistutkimusta, jossa yhdisteltiin teoreettisen ja empiirisen ongelma-analyysin periaatteita. Teoreettisen ongelma-analyysin kautta pyrittiin kartoittamaan lukio-opetuksen kannalta solukalvon sähköiseen toimintaan liittyvät keskeisimmät seikat, joihin monet virhekäsitykset liittyvät, sekä tarkastelemaan niitä eri näkökulmista. Tämä toteutettiin aiemman tutkimuskirjallisuuden avulla. Empiirisessä ongelma-analyysissä tarkasteltiin sekä lukion biologian oppikirjoja (N=3) että kevään 2021 biologian ylioppilaskoevastauksia (N=400) hermosolun aktiopotentiaalin kulkuun liittyen. Molempia aineistoja analysoitiin laadullisen sisällönanalyysin periaatteiden mukaisesti. Teoreettisesta ja empiirisestä ongelma-analyysistä saatujen tulosten perusteella kehitettiin opetusmateriaalin ensimmäinen versio. Opetusmateriaali luetutettiin läpi maisterintutkielman ohjaajilla ja opetusmateriaalia kehitettiin heiltä saatujen kommenttien perusteella. Jatkokehittämisen tuloksena syntyi opetusmateriaalin toinen ja virallinen versio. Tutkimuksen tulokset osoittivat, että solukalvon sähköinen aktiivisuus on haastava aihe sekä opetuksen että oppimi-sen näkökulmasta. Lukion biologian oppikirjoissa esiintyi epätarkkoja kohtia solukalvon sähköiseen aktiivisuuteen liit-tyen ja nämä epätarkkuudet näkyivät opiskelijoiden ylioppilaskokeen vastauksissa yleisinä virhekäsityksinä. Erityisesti esiin nousi virheellinen käsitys natrium-kaliumpumpun ioneja ”palauttavasta” vaikutuksesta aktiopotentiaalin jälkeen. Toinen yleinen virhekäsitys oli, että uusi aktiopotentiaali on mahdollinen vasta kun kalvojännite on hyperpolarisaation jälkeen palautunut lepotilaan. Tulosten perusteella voidaan todeta, että ainakin osa opiskelijoiden virhekäsityksistä on lähtöisin oppikirjoista eikä näitä virhekäsityksiä ole pystytty korjaamaan opettajan toimesta opetustilanteessa. Ylioppi-laskokeessa tehtävään vastanneista opiskelijoista 11,3 % ei osannut vastata tehtävän ensimmäiseen kysymykseen ollenkaan. Vastauksista, joissa opiskelija oli vähintään välttävällä tasolla onnistunut vastaamaan kysymykseen (N=381), 92,4 % sisälsi yhden tai useamman virhekäsityksen. Virhekäsitysten karsimiseksi paras keino on estää niiden syntyminen. Siksi tämän tutkimuksen perusteella voidaan todeta, että lukion uuden opetussuunnitelman biologian oppikirjat tulisi päivittää sellaisiksi, että virheellistä käsitystä ei pääse syntymään. Tämä ei kuitenkaan pelkästään riitä, vaan myös lukion biologian opettajien tulisi luopua vanhoista opetusdioistaan ja varmistaa, että he opettavat aihetta nykytiedon valossa oikein. Tässä apuna toimii tämän tutkimuksen osana kehitetty opetusmateriaali solukalvon sähköisestä aktiivisuudesta hermosolun aktiopotentiaalin kontekstissa. Jotta opetusmateriaalin toimivuutta ja opiskelijoiden käsitteellistä muutosta voidaan arvioida, jatkotutkimukset ai-heesta ovat tarpeellisia.
  • Suutari, Miina (Helsingin yliopisto, 2021)
    Even though bats have no specialized predators in the temperate zone, they are still predated on. In fact, 11% of their annual mortality is caused by avian predators, especially owls. Bats are particularly vulnerable at emergence from their roost because this behaviour is very predictable. Because a successful predation event is mortal, it would be expected that bats need antipredatory responses to avoid it. The time and focus for these responses need to be shared with foraging in a way that maximizes survival. I studied antipredatory responses of bats in two settings: 1. during roost emergence and 2. during foraging at tawny owl territories and at places where there have been no tawny owl sightings. I collected acoustic data from 24 roosts and 11 foraging grounds for 10-13 nights. The roost emergence data was collected with the help of citizen science. Two controlled predation threats, recorded tawny owl calls and nestling sounds, were used. Nestling sounds were only played during roost emergence. In both tests music and silence were used as controls. Owl calls, music or tawny owl territory have no effect on bat presence when they are foraging. However, bats alter their emergence time and leave over 20 minutes later when tawny owl calls are played outside the roost. There is no difference in exit time when music or nestling sounds are played. These results show that bats have antipredatory responses. They also suggest that bats may be able to recognize high-risk situations and allocate their behaviour accordingly or that they place higher importance on foraging than avoiding predation.
  • Heikkinen, Aino (Helsingin yliopisto, 2018)
    Chronic psychosocial stress is a major risk factor for anxiety disorders, but the molecular background is still poorly known. Chronic social defeat stress (CSDS) is a mouse model simulating the psychosocial stress that humans face in their life. In CSDS, the examined mice are confronted by an aggressor mouse daily for 10 days, leading to defeat behavior and predisposing to anxiety-like symptoms. Some individuals develop these symptoms (susceptible) whereas others do not (resilient). Chronic stress has been shown to alter myelin-related gene transcription and myelin microstructure. Myelin is a membranous component around axons increasing the velocity of action potentials, and it is produced by oligodendrocytes (OLs). In this study, I investigated if CSDS affects the number of OLs or the size of the myelinated area (estimating the amount of myelin) in two inbred mouse strains that differ in their innate level of anxiety: the non-anxious C57BL/6NCrl (B6) and anxious DBA/2NCrl (D2). I studied three brain regions previously associated with anxiety: the medial prefrontal cortex (mPFC), bed nucleus of stria terminalis (BNST) and ventral hippocampus (vHP). The mice used in this study were previously exposed to CSDS and divided into resilient or susceptible phenotypes, and their brains were collected together with control mice. I performed two immunohistochemical staining experiments to calculate the number of OLs and to measure the myelinated area. I used anti-CNPase for OL cell counts and BlackGold II to stain myelin. I manually calculated the number of OLs using CNPase and cell morphology as markers. I built a macro to measure the BlackGold II stained myelinated area. I also measured the thickness of the corpus callosum (CC, major white matter tract) using the CNPase stained images to examine if the thickness is affected by CSDS. I observed a strain and region-specific effect of chronic stress in the BNST; B6 resilient mice had more OLs than susceptible mice whereas no differences were seen in the D2 strain, or other B6 brain regions. The size of the myelinated area did not differ between the phenotypes in either strain. Moreover, there was no significant correlation between the myelinated area and OL cell number. The CC thickness did not differ between the phenotypes. My findings indicate that myelin and OLs are affected by stress in a region specific manner and possibly contribute to the stress-resilient behavior. The response is genetic background-dependent, as I saw differences in B6 mice but not in D2 mice. Because CC thickness did not differ between the phenotypes, we suggest that CSDS does not induce extensive white matter atrophy in the mice brain. The mechanism underlying this dynamic myelin plasticity during stress requires more investigation, but this study provides evidence that alterations in OLs associate with chronic stress.
  • Parviainen, Anna (Helsingin yliopisto, 2020)
    Jäkälät ovat sieniosakkaan ja yhteyttävän levän muodostamia symbiooseja, joista suurin osa elää maaekosysteemeissä ympäri maapalloa. Jäkälät toimivat ekosysteemeissä tärkeinä indikaattorilajeina, sillä ne ovat usein hyvin herkkiä elinympäristössä tapahtuville muutoksille, esimerkiksi ilmanlaadun huononemiselle. Sticta-suvun syanojäkäliä on tähän mennessä kuvattu noin 200 lajia erityisesti subtrooppisilta ja trooppisilta alueilta. Todellisuudessa lajimäärän arvioidaan olevan paljon suurempi. Afrikan jäkälistä tiedetään vielä suhteellisen vähän, ja tietomme Itä-Afrikan Sticta-lajeista pohjautuvat pääasiassa 1980-luvulla tehtyyn tutkimukseen. Tässä tutkimuksessa tavoitteenani oli tuottaa DNA- analyysiin perustuva selvitys Sticta-suvusta Kenian Taitavuorilla. Tutkimuksessa selvitin myös Sticta-lajien symbioottisten syanobakteerigenotyyppien levinneisyyttä Taitavuorten eri metsäsaarekkeissa ja eri Sticta-lajeissa. Tutkimukseni aineistona oli 176 jäkälänäytettä, jotka ovat kerätty Taitavuorten alueelta sekä Elgonvuoren rinteeltä Länsi-Keniasta Jouko Rikkisen ja Ulla Kaasalaisen toimesta vuosina 2009- 2017. Alustava lajinmääritys morfologian perusteella tapahtui mikroskopoimalla. Neljänkymmenenkahdeksan näytteen tarkempi lajinmääritys tehtiin DNA-menetelmin, selvittämällä jokaisesta näytteestä sienen sekä syanobakteerin genotyyppi. DNA-eristyksen, PCR:n sekä elektroforeesin tein Helsingin luonnontieteellisen museon laboratoriossa kesällä 2018. DNA- sekvensointi tehtiin Sanger-menetelmällä Saksassa GATC Biotech-yrityksen toimesta. Laboratoriotöiden tuloksena sain sieniosakkaan DNA-sekvenssin kaikkiaan 48 jäkälänäytteistä. Sekvenssien perustella 46 näytettä voitiin määrittää ennestään tunnetuiksi Sticta-lajeiksi, ja kaksi näytettä osoittautui Sticta pseudosylvatica -lajille sukua olevaksi, toistaiseksi kuvaamattomaksi lajiksi. Näytteistä löytyi kaikkiaan 21 erilaista syanobakteerigenotyyppiä. Eri metsäsaarekkeista kerättyjen näytteiden syanobakteerikoostumus ei näyttänyt poikkeavan toisistaan, mutta Sticta- lajien syanobakteerikannat poikkesivat toisistaan.
  • Neuvonen, Eerika (Helsingin yliopisto, 2019)
    Corporations’ desire to act in a responsible way as well as the amount of sustainability guidelines has increased during the past decades. Responsible Care (RC) program is an international sustainable development guideline practiced in chemical industry. The program focuses on sustainable use of natural resources, safety and sustainability of production and products, well-being of work community and reduction of waste and emissions. This study seeks to examine the correspondence of contents between national Responsible Care (RC) program in Finland and sustainability framework guidelines known worldwide. The aim of the study is to examine how corporations in chemical industry who follow the national RC program can meet the goals of sustainability framework guidelines, what are the main differences between the national RC program and other sustainability guidelines, and how the national RC program should be improved. The research methods include the content analysis and in-depth interview for corporations. In this research, the sustainability framework is built and the involved guidelines are specified. The national RC program is reflected on the sustainability framework guidelines through content analysis. A model for comparative content analysis is developed to compare the contents of sustainability guidelines by the means of qualitative data visualization through radar charts. The corporate in-depth interviews are applied with a view to obtain complete and comprehensive responses. This study demonstrates that the national RC program highly corresponds to sustainability framework guidelines in terms of environmental responsibility and safety, while the RC program less highlights the dimensions of social and economic responsibility. Based on the main differences, the possible targets for improvement in the national RC program are suggested to enhance consideration of economic and social aspects in the program. From the in-depth interviews, corporations recognize the national RC program to be a useful tool to implement and develop corporation’s sustainability work, yet there is a need to better correspondence with sustainability framework guidelines and to be more user-friendly in practice.