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Biology Paper 1 - Coggle Diagram

- - - - Nucleus - contains genetic material like DNA that controls cell functions
      - Cell Membrane - lets specific substances in and out of the cell
      - Ribosomes - synthesise proteins
      - Mitochondria - respires to create energy
      - Cytoplasm - jelly-like material where chemical reactions happen
    - - Same items as animal cells as well as:
      - Chloroplasts - contain green chlorophyll that photosynthesise
      - Vacuole - filled with cell sap to keep cell turgid
      - Cell Wall - gives the cell structure and strength
    - - Outer Layers - eukaryotes have a cell membrane (except plants which have cell wall as well) whereas prokaryotes have both a cell wall and cell membrane
      - Size - eukcaryotes are large and complex whereas prokaryotes are small and simple
      - Cell contents - both have ribosomes and cytoplasm, eukaryotics also have mitochondria and sometimes chloroplasts
      - Genetic Material - eukaryotics have a nucleus containing DNA whereas prokaryotics have a molecule of DNA in the cytoplasm
      - Eukaryotes are plant and animal cells, prokaryotes are bacteria
    - - Stem cells are cells that haven't undergone differentiation
      - They can turn into a variety of different cells
      - Embryos have embryonic stem cells that can turn into any cell
      - Adults have stem cells in specific regions of the body and can only turn into specific cells
      - They can be used to treat diseases like leukemia and they can repair damaged cells
    - - Adult stem cell transplants use a patients own stem cells so they aren't rejected
      - People can use donor stem cells, but these can be rejected
      - You can clone stem cells by transferring the nucleus from the wanted cell to the stem cell and making it divide
      - It is sometimes seen as ethically wrong to use embryos for stem cells
      - The cells can also be rejected by the patient by the immune system
      - They can be contaminated with a virus or gain a mutation
  - - - 23rd chromosome is the sex chromosome - XX is male and XY is female
      - Human cells have 23 pairs with 46 chromosomes in total
    - - 1. The DNA replicates to form two copies of each chromosome
      - 2. The chromosomes line up in the middle of the cell
      - 3. Each set of chromosomes are pulled to each end and split
      - 4. The cytoplasm and cell membrane split to form two new daughter nuclei
      - These new cells have identical genetic material to the parent cell
  - - - Particles move both ways and will eventually evenly spread about
      - Even when evenly spread about, they will continue to move
      - Some examples include oxygen and carbon dioxide diffusing in and out of alveolus
      - Factors
        
        Concentration Gradient - the greater the difference in concentration, the faster diffusion happens
        
        Temperature - the higher the temperature the more particles move
        
        Surface Area of Separator - the bigger the surface area of the cell membrane, the faster diffusion is
      - Particles move from a high concentration to a low concentration in either a gas or liquid
    - - Water moves from a high concentration to a low concentration through a semi-permeable membrane
      - A dilute solution contains a high concentration of water whereas a concentrated solution contains a low concentration of water
      - Water moves in and out of cells as they contain dilute levels of ions, sugars and amino acids
      - Plants can lose too much water if there isn't enough water in the soil, which causes water to leave the cell through osmosis
      - If a cell is too dilute then it can gain too much water and swell and burst
      - Required Practical
        
        1. Prepare a variety of boiling tubes with sugary solutions in different volumes as well as one with no sugar
        
        2. Weigh equal potato cylinders and put them in the solutions
        
        3. Weigh the potato cylinders after a specific amount of time
        
        4. A change should occur. Repeat the experiment to identify anomalous results
    - - Particles move from a low concentration to a high concentration up a concentration gradient in either a gas or liquid
      - Requires energy as it is moving against the concentration gradient
- - - - Viruses are strains of DNA surrounded by a protein coat
      - This means that a virus is not alive
      - They infect a host cell's nucleus and replicate their DNA to grow
      - These infected cells can burst and infect other cells
    - - Not all bacteria are bad, for example intestine bacteria is good
      - They replicate around every 20 minutes through binary fission
    - - Not all fungi are bad, yeast is important in making bread
      - Not all fungi are small, mushrooms are fungi and they are large and complex
    - - Protists are organisms that resemble animals
  - - - A communicable disease is one that are spread by pathogens
      - This means that they can be spread from one person to another
    - - Diseases can be spread through a variety of different ways
      - Direct Contact - contact with an infected object
      - Water - dirty water can spread disease like cholera
      - Air - some pathogens are found in droplets in the air from sneezes and coughs
      - Food - undercooked food can cause food poisoning and samonella
      - Vector - a vector is an organism that contains a pathogen that spreads it about, like a mosquito
    - - Tobacco Mosaic Virus infects tobacco-related plants and damages their chloroplasts
      - TMV reduces plant's ability to photosynthesise and shunts growth
      - No cure for TMV
    - - Human Immunodeficiency Virus is transmitted through the sharing of bodily fluids, usually through sex
      - Aquired Immune Deficiency Syndrome happens months after being infected with a HIV virus and weakens the immune system
      - No cure for HIV/AIDS
    - - Measles is a very infectious viral disease that is transmitted in the air
      - It can cause a fever and skin rashes, and infertility for adults
      - There is a vaccine against it but many underdeveloped countries don't have it
    - - Gonorrhoea is a STD caused by a bacteria
      - It creates a burning pain when urinating and can produce a thick yellow or green discharge from the genitals
      - It can be treated by antibiotics and prevented by using contraception
    - - Salmonella is a bacteria that causes food poisoning
      - It causes vomiting, diarrhoea and cramps
      - It is spread through unhyginic preparing of food and undercooking certain foods
      - All poultry are vaccinated against it in the UK
    - - Malaria is a protist spread by mosquitos
      - A mosquito sucks infected blood up, and spreads it to other people they suck
      - It causes vomiting and diarrhoea and a fever
      - It can only be stopped by preventing people from being bitten
      - This can be done by putting up mosquito nets, using insect repellant and destroying mosquito habitats
    - - Athlete's Foot is a rash caused by a fungus commonly found in between toes
      - It can be spread through communial areas like changing rooms and gyms
      - It can be treated using antifungal medication
    - - Rose Black Spot is caused by a fungus that infects roses
      - It infects leaves and creates black spots, which reduces photosynthesis
      - It can be spread through water and the air
      - It can be treated by removing infected leaves and fungicides
    - - The transmission of pathogens can be reduced or prevented
      - Sterilising Water - chemicals or UV light can kill pathogens in unclean water
      - Food Hygine - cooking foods correctly and using hygine can kill pathogens
      - Vaccination - Vaccinations intorduce antibodies into the blood that can protect the immune system
      - Contraception - stops bodily fluids from being transferred
    - - The body defends from pathogens through defensive measures to prevent them from entering and infecting, known as the first line of defence
      - Skin - covers the whole body and quickly heals if damaged
      - Nose - nose hairs trap pathogens and creates mucus,which is either blown out or swallowed
      - Trachea - the trachea has cilia hairs that push mucus and trapped pathogens up
      - Stomach - stomach acid kills pathogens trapped in the mucus
    - - Nitrate ions are needed to produce chlorophyll, and a deficiency turns the leaf yellow and reduces photosynthesis and growth
      - Magnesium ions also help produce chlorophyll
    - - Walls - bark is a layer of dead cells that protect the cells below, plant cells also have cell walls that add additional protection
      - Waxy cuticle - a thin layer on top of a leaf that stops cells from being distracted
      - Chemicals - some plants produce toxins that harm pathogens and animals
      - Thorns - some plants have thorns that prevent animals and insects from infecting it
      - Mimicry - some plants can mimic their surroundings to blend in
  - - - If pathogens pass the first line of defence then the immune system can prevent and stop infection
      - Phagocytes - specialised white blood cells that surround, engulf and digest pathogens in a move called phagocytosis
      - Lymphocytes - they detect antigens and produce antibodies to neutralise the pathogen
      - Lymphocytes can also produce antitoxins to counter any pathogen-created toxins
    - - A non-communicable disease is one that develops naturally in the body
      - When cells divide, there is a chance for it to go wrong and create a tumor
      - Malignant Tumor - cancerous tumors that can break apart and spread about the body
      - Benign Tumor - a tumor that does not spread
      - Cancer can be formed in many ways like UV light, drinking and smoking, and some viruses
      - Treatments include chemotherapy by injecting chemicals to kill cancerous cells, and radiotheraphy which uses x-rays to kill cancerous cells
    - - A vaccination is where the immune system has a dead or weakened pathogen and learns how to kill it
      - 1. A dead or weakened pathogen is injected into the body
      - 2. Lymphocytes create antibodies which lock on to the antigens and weaken the virus before a phagocyte digests it
      - 3. The body remembers what antibodies neutralised the antigens and stores it in memory cells
      - 4. Next time the body is attacked by the pathogen it is prepared
      - Herd Immunity occurs when the majority of the population is vaccinated so the pathogen struggles to spread
    - - Antibiotics - substances that slow down or stop the growth of a bacteria by damaging the cell
      - Painkillers - relieves symptoms but does not kill pathogens
      - Penicillin was the first antibiotic discovered on accident in 1928 when Alexander Fleming left bacteria in a petri dish and noticed that a mould killed them
      - Antibiotics only target specific bacteria and doesn't harm human cells or other bacteria
      - Antiboitic resistance is common for certain strains through natural selection - most of the bacteria die except for resistant ones that spread and cause problems
      - This is caused by overuse of antibiotics and not finishing their medication
      - Required Practical
        
        1. Soak filter paper disks in a solution
        
        2. Pour the sterile agar plates and allow it to set fully
        
        3. Measure the clear area around the soaked filter paper disks
    - - New drugs need to be tested and trialled before doctors prescribe them
      - Safety - how safe it is and any side effects
      - Effectiveness - how well it cures the disease or improves symptoms
      - Dosage - how concentrated the drug should be
      - First Stage - testing drugs on computer models and singular cells
      - Animal Testing - testing the drug on animals to see any side effects
      - Clinical Trials - the drug is tested on volunteers in different dosages, often also with a placebo to see how effective it is
    - - Monoclonal antibodies are identical copies of one type of antibody
      - 1. An antigen is injected into a mouse, and lymphocytes produce specific antibodies
      - 2. Spleen cells that produce lymphocytes are extracted and fused with cancerous white blood cells to form hybridoma cells, which divide infinitely
      - 3. These hybridoma cells divide and produce millions of monoclonal antibodies specific to the original antigen
      - Pregnancy tests uses special monoclonal antibodies that bind to a specific hormone called HCG that is present during pregnancy, and will change color if it is present
      - They can carry drugs directly to cancer cells and help the immune system attack them
      - They can be produced quickly, however it can be deemed unethical as it involves animals
- - - - Having a large surface area increases the rate of diffusion, as well as thin walls to let more particles in
      - One way is through villi and cilia, which are tiny little hairs that increase surface area
      - Gills in fish have a large, thin surface area where water flows through them and oxygenates the blood
    - - Lungs absorb oxygen from the air and they transfer carbon dioxide into the air from the bloodstream
      - The respiratory system is responsable for gas exchange
      - The trachea connects the mouth to the lungs by splitting into two bronchi, one for each lung
      - These bronchi split into smaller bronchioles that split further into millions of small air sacs called alveoli
      - Capillaries cover a large area of the alveoli which creates a large surface area for diffusion to happen
      - Deoxygenated blood flows in through the capillaries and releases carbon dioxide
      - Oxygen diffuses into the bloodstream and oxygenated blood flows out to the heart
      - The diaphragm is a muscle below the lungs that control the air pressure
      - When we breathe in, the diaphragm contracts and air goes into the lungs
      - When we breathe out, the diaphragm relaxes and air is pushed out of the lungs
  - - - Carbohydrates - sources of energy through glucose
      - Carbohydrates are found in starchy and sugary food
      - Proteins - needed for growth and repair
      - Proteins are found in meat products and some nuts
      - Lipids - sources of energy and needed for cells
      - Lipids are found in fatty substances
      - Glucose is needed for respiration
      - Amino acids make up proteins and are small enough to pass through the intestine walls
      - Fatty acids make up lipids along glycerol
      - Required Practicals
        
        Add iodine to the tested food when testing starch
        
        Food containing starch will turn blue-black
        
        Add biuret reagent to a solution when testing for proteins
        
        Food containing protein will turn purple
        
        Add ethanol to a test tube containing the food sample being tested for fats
        
        Pour the liquid into another test tube containing water
        
        Food containing fats will create a cloudy liquid
    - - The digestive system breaks down large foods and provides a large surface area to absorb needed molecules
      - Mouth - chews food into smaller pieces and starts digesting carbohydrates
      - Stomach - starts digesting proteins and absorbs smaller molecules like alcohol
      - Small Intestine - continues digesting proteins and carbohydrates and starts digesting lipids
      - Large Intestine - absorbs water and gets rid off unwanted food
      - The small intestine has villi which are small projections that increase surface area and contain capillaries with thin walls
    - - Most molecules are complex and need to be broken down
      - Enzymes are biological catalysts that speed up the breaking down of large molecules
      - Enzymes have an active site where the substrate fits and reacts to form a new product
      - Different enzymes have different active sites adapted for specific molecules
      - Temperature affects the enzyme as too low can reduce the number of collisions and too high can disrupt the shape of the active site
      - pH also effects the enzyme and can cause the active site to be deformed
    - - Carbohydrase - breaks down carbohydrates
      - Amylase - breaks down starch
      - Protease - breaks down proteins
      - Lipase - breaks down lipids
      - Carbohydrase are found in the mouth and small intestine
      - Protease are found in the stomach and small intestine
      - Lipase are found in the small intestine
  - - - Cells transfer essential molecules to each other through diffusion
      - However our complex bodies are too big for this to happen
      - We have tubes going to all essential organs and cells known as a transport system
      - We transfer things like nutrients, molecules and antibodies around in it
    - - The heart is a giant pump for the circulatory system
      - It has four chambers - two atria and two ventricles
      - Blood enters the heart through the atria
      - Deoxygenated blood from the body flows through the vena cava into the right atrium, and oxygenated blood from the lungs flows through the pulmonary vein into the left atrium
      - These travel down into the right and left ventricle respectably
      - The deoxygenated blood flows up out of the pulmonary artery through to the lungs, and oxygenated blood flows up out of the aorta to the rest of the body
      - Special cells control the heart beat by sending electrical signals telling the heart to beat, acting as a natural pacemaker
      - Artificial pacemakers can be fitted to stop the heart from beating abnormally, which sends electrical signals to areas of the heart to make it beat normally
    - - Blood circulates through to the lungs through the low-pressure pulmonary circulation to get the blood oxygenated
      - Blood circulates around the body through the systemic circulation to supply cells with nutrients and needed molecules
      - Unoxygenated blood travels back to the heart to be pumped to the lungs to be oxygenated
      - Blood flows through the heart twice to do a full circulation - one to the lungs and one to the rest of the body
      - Valves in the heart and aorta ensure the blood flows one way around the body
    - - Blood is transported in arteries, veins and **capillaries
      - Arteries carry oxygenated blood away from the heart, and have thick walls to pump the blood making the lumen small
      - Veins carry deoxygenated blood towards the heart