Why raise vinegar flies?
This allows students to focus on the process and techniques of investigation and the subsequent reporting. However, in Year 12 students are often given freedom to choose a topic or research question from the work covered over the whole of the course. These "Open Inquiry" EEIs may provide more ownership, engagement and deeper understanding for the students but do place a bigger demand on resources and laboratory management.
However, many teachers have found strategies to manage this should they choose to opt for a Open EEIs.
Observe with a compound microscope the apex of an onion, garlic, or bean root. You can observe cells and their chromosomes in various stages of the cellular division, or mitosis. 1 - To carry out this experiment, immerse the lower part of an onion in water and leave it to root for four or five days. (soft focus) Two-cell embryo, Mitosis under microscope Cell Division - Mitosis and Meiosis, illustration "stages of mitosis" lab using onion root tip slidesdo the "modeling meiosis" lab using modeling clay of different colors to repesent the chromosomessimulate mitosis and meiosis in an imaginary animal called a . Mitosis and the cell cycle While making your observations, consider the Procedure for determining the length of the stages of mitosis Locate the meristem region of the root tip. 1. Starting under the 10x objective, find the region of active cell division. Microsoft Word - Onion root timberdesignmag.com
A Materials Requisition Form accompanies this document. My thanks to Biology teachers from Nanango for sharing this.
Examples of Risk Assessment forms can be found in the tasks available on this page. A comprehensive form developed over several years by Urangan SHS can be found here: It is only an example and should not be assumed to necessarily meet the legal and safety obligations of any particular school or situation.
The method of artificial variation: The method of concomitant variation: This is also called a "correlation method". You can think that nature has manipulated the variables but it is still appropriate to class one as dependent and one as independent.
For example, do young leaves have the same density and distribution of stomata as older leaves; or how does temperature IV in a natural environment affect stoma opening DV?
In this second case you do not need you to control the environmental temperature, but you do need to measure the DV at different temperatures. The difficulty with the second approach is the control of other potentially influential variables such as humidity - as you have to take what you get.
However, that does not preclude the variables in relationship being considered the IV and DV or being graphed as such. One way to address the confounding variables eg humidity is to collect data on the other variable as well. You can run the statistics on each pair separately, but, for students who are not that "stats-savvy" then they could look for interactions between them at a visual level.
Food, as well as meeting the nutritional requirements of humans, will also meet the nutritional needs of a vast range of micro-organisms. These microbes will multiply rapidly in food, given the appropriate conditions such as temperature, pH and moisture.
The flavour, aroma and texture will ultimately be affected. Those most affected by food poisoning are the elderly, the young and immune suppressed individuals. A petri dish culture of the yeastlike organism fungus Candida krusei, after 10 days growth on dextrose agar.
This species is known to be a food spoilage organism.
Dichloran Rose Bengal Chloramphenicol Agar is a commercially specialist culture medium for viable yeasts and moulds in food products. It incorporates Rose Bengal, which both helps limit colony size and is selective against bacteria.
Effects of different anti microbials on bacterial growth Joseph Lister first introduced aseptic surgery in when he used a spray of carbolic acid phenol C6H5OH as a germicide. Since then the control of growth by antimicrobial compounds has grown into a multi-billion dollar industry. A good EEI is to assess the effect of a variety of antimicrobial disinfectants on bacterial growth.
Our labbies prepare the plates and order in E. Small paper discs like out of a hole punch are sterilised and then soaked into different anti-microbials. The discs are placed onto the agar plates and then into the incubator for a couple of days.
If the anti bacterial is effective there is a clear ring around the disc where the E. Students have used the width of this ring to indicate effectiveness and to collect quantitative data.
The experiment can work quite well; keen students have then researched the active compounds within the antibiotic, how they act upon the bacteria and link to the results observed". No single disinfectant is ideal. Each has its advantages and disadvantages. For example, phenols sterilise well but are corrosive and toxic.
Risk assessment including disposal of waste is vital. This photo shows zones of inhibition around filter paper disks saturated with anti-microbial compounds. The diameter of the zone of inhibition is a measure of the effectiveness of an anti-microbial compound. Mounting concerns over the potential for microbial contamination and infection risks in the food and general consumer markets have led to increased use of antiseptics and disinfectants by the general public.
Despite this, much is still to be learnt about the mode of action of these active agents on bacteria such as those shown above.At h, h, h and 15 h, cells were collected and stained with PI (Sigma-Aldrich), and then cell cycle was detected by flow cytometry.
% S-phase cells, % G2-phase cells, % M-phase cells and % G1-phase cells were obtained respectively, which showed good cell synchronization (Supplementary Fig. S1). In each experiment, different phases of cells were cultured for fixed time as .
One-Hundred-and-Twenty-Sixth Annual Undergraduate Bulletin –18 The Undergraduate Bulletin is also available on the Web at timberdesignmag.com An epidermal growth factor (EGF) stimulates a cell to enter mitosis by binding to a receptor on the cell's plasma membrane.
The EGF receptor is a product of a _____ gene. You are studying a cell line in in which one cell cycle takes approximately 24 hours. You perform FACS analysis on a population of your dividing cells. Your cells are growing asynchronously meaning different cells are in different stages of the cell cycle.
Effects of different anti microbials on bacterial growth. Joseph Lister first introduced aseptic surgery in when he used a spray of carbolic acid (phenol C 6 H 5 OH) as a germicide.
He was able to reduce mortality of post operative surgery by up to 45%. Mitosis, Meiosis and the Cell Cycle Purpose: This activity is designed to familiarize you with the phases of mitosis and meiosis and compare these processes .