NATIONAL SENIOR CERTIFICATE GRADE 12 LIFE SCIENCES P1 FEBRUARY/MARCH 2011 MARKS: 150 TIME: 2½ hours This question paper consists of 14 pages. Copyright reserved Please turn over Life Sciences/P1 2 NSC DBE/Feb. – Mar. 2011 INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. 1. Answer ALL the questions. 2. Write ALL the answers in your ANSWER BOOK. 3. Start the answers to EACH question at the top of a NEW page. 4. Number the answers correctly according to the numbering system used in this question paper. 5. Present your answers according to the instructions of each question. 6. Do ALL drawings in pencil and label them in …show more content…
The second slide she filled with a 5% sugar solution. The third slide she filled with a 10% sugar solution. The fourth slide she filled with a 15% sugar solution. The fifth slide she filled with a 20% sugar solution. She transferred the same number of pollen grains from the anthers of a flower into each cavity of the five slides. A cover slip was gently lowered onto the slide. All five slides were placed in a warm incubator and left for one hour. Each slide was then examined under a microscope and the number of pollen tubes in each slide was counted and recorded in the table below. Concentration of sugar solution (%) 0 5 10 15 20 Number of pollen tubes 0 7 11 15 21 1.4.1 Explain why Zama used distilled water in the first cavity slide. (2) 1.4.2 State THREE ways in which this investigation would be improved to get more reliable results. (3) 1.4.3 Copyright reserved Describe a conclusion for the above investigation. (2) (7) Please turn over Life Sciences/P1 1.5 7 NSC DBE/Feb. – Mar. 2011 The diagram below represents a karyotype of a human cell. 1 6 2 3 7 13 14 19 20 4 8 9 10 15 11 16 21 5 12 17 22 18 23 1.5.1 How many chromosomes are present in this karyotype? (1) 1.5.2 Is this karyotype that of a man or a woman? (1) 1.5.3 Give a reason for your answer to QUESTION 1.5.2. (2) 1.5.4
Type the answers to the assignment's questions. Use complete sentences unless the question says otherwise. You will have more than one day to complete an assignment. At the end of each day, be sure to save your progress.
There are many procedures during this lab and many materials needed for an accurate analysis of data. First, fill a 100 mL graduated cylinder with 50 mL of water. Add 25 germinating peas and determine the amount of water that is displaced. Record this volume of the 25 germinating peas, then remove the peas and put those peas on a paper towel. They will be used for the first respirometer. Next, refill the graduated cylinder with 50 mL of water and add 25 non-germinating peas to it. Add glass beads to the graduated cylinder until the volume is the same to that of germinating peas. Remove the beads and peas and put on a paper towel. They will be used in respirometer 2. Now, the graduated cylinder was filled once again, determine how many glass beads will be require to reach the same volume of the germinating peas. Remove the beads and they will be used in respirometer 3. Then repeat the procedures used above to prepare a second set of germinating peas, dry peas and beads, and beads to be used in respirometers 4,5,and 6, the only difference is the temperature of the water.
7. Explain how incubation plant tissues in a series of dilutions of sucrose can give an
1B). The tube with germinating peas had the heights rate of oxygen consumption. The reasoning behind this is because the peas were doing aerobic respiration in which the oxygen was consumed by the peas and the carbon dioxide was released from the peas. The thermobar tube had the lowest rate of oxygen consumption because the glass beads did not undergo aerobic respiration, rather potassium hydroxide reacted with carbon dioxide to form the potassium carbonate and water. In fact, the thermobar data displayed a negative slope of the amount raw oxygen consumption, showing that as the reaction continued that the amount of oxygen that was consumed decreased. In regards to the slopes, the scatterplot shows that there was a positive slope for the germinating
Question #1 is worth 5 points – all others are worth 1 point each. Either type your answers directly onto THIS sheet OR create a new file and number your answers 1, 2, 3, etc.
The materials used in this lab were distilled water, a vase with Control solution, tap water in a plastic tray. Ag+ solutions with specific concentrations such as, 0.25 (Mm), 0.50 (Mm), 1.00 (Mm), 2.00(Mm), 4.00 (Mm), and AOA solutions with specific concentrations such as, 0.2 (Mm), 0.4 (Mm), 0.6 (Mm), 0.8 (Mm), and 1.0 (Mm), eleven carnations for each group and a razor blade and an electronic balance.
Directions: Answer each question. Be sure to answer the ENTIRE question. See numbers in parentheses ( ) for point values. You must handwrite your answers in the space provided. In addition to answering the questions, you will be graded 5 points based on the neatness of your submitted work (including your handwriting). If I cannot read the answer, you will get 0 points for the question. If you use another source (website, journal article, etc.) to help you answer a question, you must cite it.
The point where the fronds were highest in population was between 5/22/2015 to 5/26/2015, with 14 fronds present. On the final day of the testing period, the pH 5 tubes had 13 fronds, which was the highest population outcome of all the tubes. The pH 6 tubes’ population growth was not stable. At the start, there were 6 fronds and it increased up to 8 fronds (on 5/13/2015), but it decreased after that. On 6/1/2015, it was able to grow again up to 3 fronds and then to 5 fronds the day after. The pH 7 tubes’ population seemed constant staying around 8 or 9 fronds between the dates 5/15/2015 to 5/26/2015. The ‘control’ test tube could be considered the most stable of all the tubes because it didn’t have a time period where the population increased or decreased significantly. The only time the number of fronds decreased was between dates 5/26 to 5/28, losing 2 fronds. From the start of this experiment, the control tube’s population steadily increased with 9 fronds as the
Cross-pollination took place on day 29 and followed a very specific procedure. Our group observed flowering in cells three (two flowers) and five (four flowers). Pollen was carefully transferred from the stamen of each plant to the pistil of another using a small brush. This was repeated several times to ensure success. Finally, buds without flowers were trimmed from each plant. On day 36, seed pods were counted and a total of 12 were recorded and photographed. Buds and flowers were clipped from all plants on day 43 and 25 seeds pods were observed. The three lab periods proceeding the final clipping/trimming (days 50-64) were dedicated to drying the plants and seed pods.
The filament works alongside the anther in the production of a plant’s pollen, of which will be used for fertilization and reproduction.
From table 1 it is observed that normal karyotype is 194 (84%) and abnormal karyotype is 37 (16%), out of which numerical is about 16 (43%), XY female and variants 8 (22%) and structural 13 (35%). The most commonly observed karyotypes were 45,X/46,XX (12/75%) under numerical abnormality, 46,XY female (4/50%) under XY female and variants and 45,X/46,X,i(Xq) (4/30.7%) and 46,X,i(Xq) (3/23.1%) under structural abnormality.
Each treatment number represented a specific treatment, treatment 1 was the control, treatment 2 was the N-deficient, treatment 3 was he P-deficient, treatment 4 was the K-deficient and treatment 5 was the water treatment. Starting from the bottom of the container there were several layers; folded paper towels, cotton, another layer of folded paper towels, 30 mL of the treatment, evenly spread 10 mL of rye seeds, folded paper towels and 20 mL of the same treatment. The containers were placed under the fluorescent light for two weeks. After two weeks, using the dissecting probe remove 20 plants from the middle, left and right corners from each growth container. The seed and root was removed using scissors, leaving the shoot behind. The shoot was then placed on the scale and weighed for shoot biomass, in milligrams, which was converted to grams by multiplying 1000, and the shoot length was recorded in centimeters. The shoot’s biomass and length were transferred to the Data Sheet and to a table on Excel. Two individual graphs, shoot’s biomass and length, were made on Excel after calculating the statistical data.
Aim The aim of this experiment is to investigate the effects of different concentrations of sugar solutions on the rate of osmosis in plant cells.