Biology paper one 2024 questions and their correct answers for the best students, Exams of Biology

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Biology paper one 2024 questions

and their correct answers for the

best students

01.4 suggest one reason why berries are used instead of leaves or roots - Verified Answer berries have the lowest mass, meaning it has a dosage that does not cause harm 01.2 name the type of tissue in plants that contains stem cells. - Verified Answer meristematic tissues 01.3 Which plant does aspirin originate from? - Verified Answer willow tree 01.1 What is a tissue? - Verified Answer a group of cells working together to perform a shared function, and often with similar structure. 01.5 Calculate the mass of chemical Ain 200 g of the leaves with chlorosis. Give your answer in mg. - Verified Answer 0.60×1.2grams=0.72grams 0.72grams×2=1.44grams 1.44grams×1000mg/gram=1440mg 01.6 suggest one reason why the leaves of the deadly nightshade plant have chlorosis.

• Verified Answer they have iron deficiency 01.7 It is important for drugs to be tested in clinical trials before the drugs are approved for use by the public. Give two reasons why. - Verified Answer safety: Clinical trials identify potential side effects and adverse reactions, ensuring the drug is safe for public use. Efficacy: Trials confirm the drug effectively treats the condition it is intended for, proving its therapeutic benefits. 01.8 suggest one reason why a report making claims about the effects of chemical A may be biased. - Verified Answer they may be trying to sell it to make money 01.9 How can scientists be sure that claims about new drugs are valid? - Verified Answer peer review 2.01 Which part of the heart receives oxygenated blood from the lungs? - Verified Answer A

2.02 Which part of the heart pumps deoxygenated blood to the lungs? - Verified Answer C 2.03 Where in the heart is the pacemaker found? - Verified Answer right atrium 2.04 describe two ways that the structure of an artery is different from the structure of a vein - Verified Answer arteries have thicker walls with more smooth muscle and elastic fiber whereas veins have thinner walls Veins contain one-way valves to prevent backflow, whereas arteries typically don’t have valves 2.05 describe the trend shown in table 2 - Verified Answer the higher the percentage (%) of coronary artery that is blocked, the lower the blood flow in cm3 /minute 2.06 ADVICE - Verified Answer GO UP IN TENS 2.08 explain the effect of a partly blocked coronary artery on the human body - Verified Answer -less blood supplied to the heart muscle === less oxygen supplies to the heart muscle cells === less blood pumped around the body === less oxygen supplies to tissues === less aerobic respiration causes less energy released -person becomes tired -more anaerobic respiration leads to muscle fatigue due to lactic acid production 2.09 explain how one treatment for a blockage in a coronary artery works. - Verified Answer Coronary angioplasty widens the blocked artery with balloon inflation. Stent placement maintains artery openness. 03.1 how do Salmonella bacteria in food cause the symptoms of vomiting and diarrhea?

• Verified Answer salmonella toxins irritate the gut lining, inducing vomiting and diarrhea. 03.2 explain how -the immune systems of animals respond to a vaccination -the immune response in farm animals prevents an outbreak of food poisoning in humans. - Verified Answer FIRST BP -vaccination introduces weakened or inactive pathogens, stimulating an immune response. -the body recognizes antigens and produce specific antibodies against the pathogen. -these become memory cells, providing long-term immunity. -memory cells quickly recognize and mount a robust immune response upon subsequent pathogen exposure. SECOND BP -animals are vaccinated against pathogens like Salmonella.

-vaccinated animals shed fewer pathogens in feces. -lower pathogen levels in animal products decrease the risk of contamination. -vaccination reduces the likelihood of contaminated food reaching consumers, preventing foodborne illness outbreaks. 03.3 describe two aseptic techniques the scientists should have used in the investigation. - Verified Answer -taking the lid off for as short as possible and keeping it close to the dish to avoid other bacteria and too much oxygen entering -avoiding cross contamination by using new or thoroughly washing equipment in- between use 03.4 explain why scientists use 37 °C but students must use 25 °C to incubate bacteria.

• Verified Answer scientists use 37C to mimic the perfect temperature to stimulate bacterial growth. Students, however use 25C, keeping harmful bacteria from growing, giving them more control 03.5 What is the purpose of the paper disc with no antibiotic in Figure 4? - Verified Answer to determine the natural growth rate and to inform scientists if any other bacteria that they had not added were present 03.7 describe how the results in Figure 4 could be used to obtain a quantitative comparison of antibiotics A and B. - Verified Answer by measuring the diameter of zones of inhibition for comparison, we can determine with antibiotic has a bigger effect 03.8 suggest why antibiotic Bno longer had an effect. - Verified Answer development of antibiotic resistance in the bacterial population 03.9 explain why the cells burst - Verified Answer cells burst when placed in a hypertonic solution, where water moves out due to osmosis, causing the cell to shrink and potentially rupture due to the loss of water. 04.1 explain two effects of anaerobic respiration on the person's body - Verified Answer -anaerobic respiration, when oxygen is scarce, prompts cells to switch to anaerobic metabolism, yielding lactic acid instead of CO2 and H2O. Lactic acid buildup causes muscle fatigue, cramps, and soreness, impairing muscle function and endurance, notably during intense physical activity. -anaerobic respiration yields less energy than aerobic respiration, resulting in decreased endurance during prolonged physical exertion. This limits the body's ability to sustain energy production, leading to quicker fatigue, especially during high-intensity exercise. 04.3 explain how taking anabolic steroids could improve an athlete's performance. - Verified Answer anabolic steroids enhance muscle mass, strength, and recovery in athletes.

04.4 What type of cell is created when a mouse lymphocyte and a tumor cell combine? - Verified Answer hybridoma 04.5 describe how scientists make monoclonal antibodies using the cell created when a mouse lymphocyte and a tumour cell combine. - Verified Answer -hybridoma cells come from the fusion of mouse lymphocytes and tumour cells -they are cloned -cloned hybridoma cells are grown in large quantities, and this is where monoclonal antibodies are harvested and purified. 04.6 what property makes a monoclonal antibody useful in detecting the presence of an anabolic steroid in urine? - Verified Answer anabolic steroid 04.7 suggest the purpose of the control area in the test strip. - Verified Answer to confirm the test is working 04.8 suggest one reason why the test did not work. - Verified Answer reagents have expired. They can lose their effectiveness, leading to inaccurate or no reactions 04.9 Which athlete has tested positive for anabolic steroids in their urine? - Verified Answer A 05.1 What term describes an organism that passes a pathogen from one person to another person? - Verified Answer vector 05.2 describe three ways the structure of the malarial protist is different from the structure of a prokaryotic cell - Verified Answer - malarial protist is bigger

• Concentrated genetic material in the nucleus
• Mitochondria 05.3 explain why the bursting of red blood cells causes tiredness. - Verified Answer bursting red blood cells reduces oxygen delivery and causes anemia, leading to tiredness, fatigue, and increased energy demands for recovery 05.4 differences between sexual and asexual reproduction - Verified Answer -sexual slower -asexual faster -slower allows more room for adaption -asexual no room for genetic diversity -asexual can happen through many methods -sexual goes through a specific order

05.5 suggest how the drug prevents mitosis occurring - Verified Answer the drug may prevent mitosis by interfering with microtubule formation or function. This disrupts the mitotic spindle, preventing proper chromosome segregation and cell division. 05.6 describe the process of cell division by mitosis - Verified Answer mitosis begins with interphase, followed by prophase (chromosomes condense), metaphase (chromosomes align), anaphase (chromatids separate), telophase (nuclear envelopes form), and cytokinesis (cytoplasm divides), resulting in two genetically identical daughter cells. 06.1 complete the symbol equation for photosynthesis. - Verified Answer 6CO2+6H2O→C6H12O6+6O Milk decay required practical - Verified Answer 1.place 20 cm3 of fresh milk into three beakers

2. Decide the three temperatures you will investigate. Write these onto the sides of the beakers. They may be 5, 20 and 35°C.
3. Use universal indicator paper or solution to determine the pH of the milk in the three beakers
4. Cover each beaker in cling film and incubate at the appropriate temperature
5. Use universal indicator paper or solution to determine the pH of the milk in the three beakers after 24, 48 and 72 hours How does milk decay - Verified Answer as milk decays its pH reduces. This is because bacteria present in milk carry out a chemical process to provide them with energy. This process converts lactose sugar in the milk to lactic acid, and producing this acid reduces the pH of the milk.