Biology paper 1

• All life consists of cells which can be seen with a normal light microscope and the nucleus but the subcellular structures may not be visible using an electron microscope.
• Electron microscopes have a better resolving power and a higher resolution than light microscopes, allowing us to see finer details of the organelles.
• The size of a cell can be calculated by knowing the magnification of the microscope, which is equal to image size divided by object size.
• The actual cell size can be measured by dividing the image size by the magnification.
• Eukaryotic cells have a nucleus in which their DNA is found, while prokaryotic cells don't have a nucleus and their DNA is found in a ring called a plasmid.
• Both eukaryotic and prokaryotic cells contain similar organelles or subcellular structures such as the cell membrane, which keeps everything inside the cell but is also semi-permeable, allowing certain substances to pass through.
• Most bacteria have an extra cell wall made of cellulose providing a rigid structure for them.
• Cytoplasm is the liquid that makes up the cell in which most chemical reactions take place.
• Mitochondria is where respiration takes place, releasing energy for the cell to function.
• Ribosomes are where proteins are assembled or synthesized.
• Plant cells contain chloroplasts which contain chlorophyll and photosynthesis takes place.
• Plant cells also contain a permanent vacuole in which sap is stored.
• This process is what you feel when your muscles ache during intense exercise.
• Plants and yeast cells respire anaerobically, but slightly different, where glucose is turned into ethanol and carbon dioxide.
• Aerobic respiration means with oxygen, represented by the word and balanced chemical equation.
• The rate of photosynthesis can be measured by submerging Pond weeds in an inverted measuring cylinder and measuring the volume of oxygen made over time.
• The oxygen debt built up during exercise means more oxygen is needed afterward to break it down in the liver.
• Anaerobic respiration occurs when there's a lack of oxygen, and glucose is instead converted straight into lactic acid, which releases less energy.
• During exercise, the breathing rate and heart rate increase to increase the rate of oxygen delivered to cells for respiration.
• Metabolism is defined as the sum of all reactions in a cell or organism, including respiration, conversion of glucose and starch, glycogen and cellulose, glucose build-up into cellulose, and the breakdown of excess proteins.
• Every cell, including red blood cells, has a mitochondria which is where respiration takes place to provide energy for other chemical reactions, movement, and warmth.
• The independent variable in photosynthesis can be the light intensity, which is changed by varying the distance from the light source, such as a lamp.
• Light intensity follows an inverse Square relationship, meaning if you double the distance from the light source, the intensity quarters.
• Bacteria multiply by binary fission, so the number doubles every 10 minutes, meaning that if we started with one bacterium after an hour, we'd have 2 to the power of 6 that's 64.
• Malaria is caused by a protist that burrows into red blood cells to multiply then burst out, destroying the red blood cell in the process.
• Monoclonal antibodies are made from clones of a cell which is able to produce a specific antibody to combat a disease.
• Photosynthesis happens in chlorophyll and chloroplasts in plant cells to provide food for the plant.
• Increase in light intensity or increasing CO2 concentration can be a limiting factor in the rate of photosynthesis.
• Rose black spot and purple black spots appear on the leaves of plants due to fungal infections, causing stunted growth.
• Malaria is spread by mosquitoes, making them the vector for the disease.
• The immune system stores a copy of this antibody next to a copy of the antigen, so it's ready to stop the pathogen from causing an infection next time it's exposed to it.
• An antigen on a pathogen will have a specific shape, so only an antibody that fits it will neutralize it.
• Tobacco mosaic virus affects plants by discoloring leaves due to inhibiting chlorophyll production, causing stunted growth.
• If pathogens are unknown to the immune system, lymphocytes will start making all different shapes until one fits.
• Phagocytes ingest and destroy pathogens.
• The rate of photosynthesis is increased with higher temperature unless it's so high that enzyme denaturing occurs.
• A vaccine is a dead or inert version of a pathogen used to expose the immune system to the pathogen so it can produce the antibody without it infecting the body.
• Penicillin was the first antibiotic, and there are good bacteria in our body, so antibiotics are designed to be as specific as possible.
• White blood cells, particularly lymphocytes, produce antitoxins to neutralize the poisons pathogens produce and also make antibodies which stick to the antigen on a pathogen, stopping them from infecting more cells and clumping together.
• Drugs used to be extracted from plants and other organisms, for example, aspirin comes from willow trees and penicillin from a mold.