Neco 2023 Biology questions and answers
Answer three questions only
Health according to the World Health Organization (WHO is defined as a state of complete physical mental and social well-being and not merely the absence of disease or infirmity.
(i) Personal lifestyle choices such as diet physical activity tobacco and alcohol use and sexual practices can significantly impact health.
(ii) Factors like socioeconomic status education employment and social support systems play a vital role in health outcomes.
(iii) Physical Environment: The quality of air water and sanitation as well as the availability of healthcare facilities can influence the overall health of individuals.
(iv) Genetics and Biology: Genetic factors inherited traits and biological characteristics can have an impact on an individual’s susceptibility to certain diseases or conditions.
(i) Digestion: The small intestine receives partially digested food from the stomach and continues the process of breaking down complex food particles into smaller molecules. It utilizes enzymes produced by the pancreas and the small intestine itself to aid in the breakdown of proteins carbohydrates and fats.
(ii) Absorption: The inner lining of the small intestine contains numerous tiny finger-like projections called villi. These villi increase the surface area available for absorption. The small intestine absorbs most of the digested nutrients including glucose amino acids and fatty acids into the bloodstream.
(iii) Secretion: The small intestine secretes various enzymes mucus and hormones necessary for digestion and absorption. It releases digestive enzymes and bile into the small intestine to facilitate the breakdown of nutrients.
(PICK ANY TWO)
(i) Involves the breakdown of complex food molecules into simpler forms through chemical reactions facilitated by enzymes.
(ii) Occurs primarily in the mouth (with saliva stomach and small intestine.
(iii) Examples of chemical digestion include the breakdown of proteins into amino acids carbohydrates into sugars and fats into fatty acids and glycerol.
(iv) Requires the presence of specific enzymes for the breakdown of different types of nutrients.
(PICK ANY TWO)
(i) Involves the physical breakdown of food into smaller particles through chewing churning and mixing actions.
(ii) Occurs primarily in the mouth (with teeth stomach and small intestine.
(iii) Examples of mechanical digestion include chewing stomach contractions and the segmentation movement of the small intestine.
(iv) Relies on physical force such as teeth grinding stomach contractions and peristalsis to break down and mix the food.
(i) Ultrafiltration: Ultrafiltration is a vital process that occurs in the kidneys. It is the first step in urine formation and involves the filtration of blood through specialized filters known as glomeruli. The pressure of blood forces small molecules like water glucose amino acids salts and waste products to pass through the glomerular capillaries and enter the renal tubules. Larger molecules such as blood cells and proteins are retained in the bloodstream. This process ensures that only small molecules are filtered into the urine while important substances are reabsorbed later in the tubules.
(ii) Selective Reabsorption: Selective reabsorption occurs in the renal tubules of the kidneys. After the initial filtration process essential substances such as glucose amino acids water and salts are selectively reabsorbed into the bloodstream. This process helps maintain the body’s homeostasis by conserving valuable substances that the body needs rather than excreting them in the urine. The selective reabsorption process is regulated by specific transporters and hormones to ensure an appropriate balance of substances in the body.
(iii) Vasoconstriction: Vasoconstriction is the narrowing or constriction of blood vessels. It occurs when the smooth muscles around the blood vessels contract causing a decrease in their diameter. This constriction reduces blood flow and can be useful in certain situations such as during bleeding or when redirecting blood to specific areas of the body. Vasoconstriction is regulated by the nervous system and various hormones and plays a crucial role in regulating blood pressure blood flow distribution and body temperature.
(i) Improved Physical Fitness: Regular exercise promotes cardiovascular health strengthens muscles and bones and enhances overall physical fitness. It increases stamina flexibility and strength making daily activities easier to perform. Exercise also helps maintain a healthy weight and improves body composition.
(ii) Mental Well-being: Exercise has a positive impact on mental health by reducing stress anxiety and symptoms of depression. It stimulates the release of endorphins which are natural mood-enhancing chemicals in the brain. Regular exercise can improve sleep quality boost self-esteem and contribute to a sense of overall well-being.
(iii) Disease Prevention: Engaging in regular exercise can significantly reduce the risk of developing various chronic diseases such as heart disease high blood pressure type 2 diabetes and obesity. Exercise improves cardiovascular health lowers blood cholesterol levels regulates blood sugar levels and helps maintain a healthy body weight. Additionally exercise can strengthen the immune system leading to a reduced risk of certain infections and illnesses.
(PICK ANY TWO)
(i) Occurs in the absence of oxygen.
(ii) Yields a low amount of energy (ATP) compared to aerobic respiration.
(iii) Examples of products include lactate (in humans) or alcohol and carbon dioxide (in yeast).
(iv) Takes place in the cytoplasm of cells.
(PICK ANY TWO)
(i) Requires oxygen to occur.
(ii) Yields a high amount of energy (ATP) compared to anaerobic respiration.
(iii) Produces carbon dioxide and water as byproducts.
(iv) Takes place in the mitochondria of cells.
(i) Limited access to healthcare facilities: Lack of easily accessible healthcare facilities especially in rural areas can hinder the successful immunization of children. If healthcare centers are located far away or are not properly equipped it becomes difficult for parents to bring their children for immunization.
(ii) Lack of awareness and education: Insufficient knowledge and awareness about the importance of immunization can be a significant barrier. Parents who are not aware of the benefits and safety of vaccines may be hesitant to vaccinate their children or may have misconceptions about vaccines.
(iii) Socio-cultural beliefs and practices: Socio-cultural beliefs and practices can sometimes influence the acceptance or refusal of immunization. Certain cultural or religious beliefs may conflict with the concept of vaccination leading to skepticism or resistance.
(PICK ANY FOUR)
(iv) Hepatitis B
(vi) Influenza (Flu)
-Four Types of Cancer-
(i) Breast Cancer: Breast cancer occurs when abnormal cells in the breast grow and divide uncontrollably. It is the most common cancer among women globally.
(ii) Lung Cancer: Lung cancer develops when abnormal cells in the lungs multiply rapidly. It is primarily caused by tobacco smoke and it is the leading cause of cancer-related deaths worldwide.
(iii) Colorectal Cancer: Colorectal cancer affects the colon and rectum. It usually begins as a growth called a polyp which can become cancerous over time. Regular screening and early detection can significantly improve outcomes.
(iv) Prostate Cancer: Prostate cancer affects the prostate gland in men. It typically grows slowly and may not cause significant symptoms in the early stages. Regular prostate cancer screening is essential for early detection and better treatment options.
(i) Unexplained Weight Loss: Sudden and unintentional weight loss without changes in diet or physical activity can be a symptom of various types of cancer.
(ii) Fatigue: Persistent fatigue or exhaustion that does not improve with rest can be an early sign of cancer. It is a common symptom experienced by cancer patients.
(iii) Changes in the Skin: Skin changes such as the development of new moles changes in the color or size of existing moles or the appearance of sores that do not heal can signify certain types of skin cancer.
-Three Preventive Measures-
(i) Lifestyle Modifications: Adopting a healthy lifestyle that includes a balanced diet regular exercise limited alcohol consumption and avoidance of tobacco products can help reduce the risk of certain cancers.
(ii) Vaccination: Vaccines such as the HPV vaccine against cervical cancer and the Hepatitis B vaccine help prevent infections associated with certain types of cancer.
(iii) Regular Screening: Regular cancer screenings such as mammograms for breast cancer Pap smears for cervical cancer and colonoscopies for colorectal cancer can help detect cancer at early stages when treatment outcomes are generally more favorable.
Chemotherapy is a cancer treatment that uses drugs to destroy or slow down the growth of cancer cells. It works by targeting and killing rapidly dividing cells including cancer cells.
(i) Lack of Hygiene: Poor personal hygiene practices such as inadequate hand washing improper food handling and lack of sanitation facilities can facilitate the spread of diseases. Proper hygiene is essential in preventing the transmission of many infectious diseases.
(ii) Close Contact: Diseases can spread more easily when individuals are in close proximity to each other. The closer the contact the greater the risk of transmission. Examples include respiratory droplet transmission in conditions like influenza or direct contact transmission seen in sexually transmitted infections.
(iii) Weak Immune System: Individuals with weakened immune systems such as those with certain medical conditions or on immunosuppressive medications are more susceptible to infections. A weakened immune system makes it easier for pathogens to invade the body and cause diseases.
(iv) Environmental Factors: Environmental conditions can favor the spread of diseases. Factors such as poor air quality contaminated water sources overcrowded living conditions and exposure to vector-borne diseases (transmitted by insects like mosquitoes) can contribute to disease transmission.