ALL OF BIO PAPER 1 (BRIEF SUMMARY).

• Cells can be seen with a light microscope, but subcellular structures are not visible
• Electron microscopes allow us to see finer details of organelles
• Magnification is equal to image size divided by object size
• Eukaryotic cells have a nucleus where DNA is found (e.g., plant and animal cells)
• Prokaryotic cells do not have a nucleus and their DNA is found in a plasmid
• Cell membrane keeps everything inside the cell and is semi-permeable
• Plant cells and most bacteria cells have an extra cell wall made of cellulose
• Cytoplasm is the liquid where most chemical reactions take place
• Mitochondria is where respiration takes place
• Ribosomes are where protein synthesis occurs
• Plant cells also contain chloroplasts for photosynthesis and a permanent vacuole
• Stem cells are found in human and animal embryos and the meristem of plants
• Diffusion is the movement of molecules from high to low concentration
• Osmosis is the diffusion of water across a semi-permeable membrane
• Active transport uses energy to move substances against a concentration gradient
• Tissues form organs, and organs work together in organ systems
• Enzymes are biological catalysts that break down larger molecules into smaller ones
• Enzyme activity increases with temperature until denaturation
• The respiratory system involves breathing and gas exchange
• The circulatory system is a double pump system with oxygenated and deoxygenated blood
• The heart pumps blood to the lungs for oxygenation and to the body for circulation
• Blood vessels include arteries, veins, and capillaries with specific functions
• The heart has its own blood supply delivered by the coronary artery
• The heart is a muscle that needs its own supply of oxygen and blood to keep pumping
• The coronary artery delivers oxygenated blood to the heart muscle
• Blockage of the coronary artery by fatty deposits can lead to a heart attack, known as coronary heart disease (CHD)
• Faulty heart valves can cause backflow, which can be replaced with artificial valves
• Blood carries red blood cells, white blood cells, and platelets
• White blood cells combat infections
• Platelets clump together to form clots and stop bleeding
• Cardiovascular disease (CVD) is a non-communicable disease
• Non-communicable diseases are caused by factors within the body, such as obesity, high sugar intake, and lack of exercise
• Type 2 diabetes can be caused by obesity and high sugar intake
• Alcohol consumption can lead to liver diseases
• Smoking can lead to lung disease or cancer
• Cancer is the result of damaged cells dividing uncontrollably, leading to tumor formation
• Leaves allow for transpiration, the movement of water into roots and up the xylem
• Roots absorb water and mineral ions for the plant
• Xylem are long tubes that transport water in plants unidirectionally
• Phloem transport sugars, food, and sap bidirectionally in plants