James Burns
Mind Map by James Burns, updated more than 1 year ago
James Burns
Created by James Burns over 6 years ago


Biology B2 Mindmap

Resource summary

  1. Cells
    1. Both animal and plant cells have similar parts. Plant and algal cells have additional features.
      1. Root hair cells have a tiny hair like extension to increase the surface area so that it can absorb more water and ions
        1. Palisade cells are column-shaped cells that are packed with chloroplasts for photosynthesis
          1. Xylem cells are long, thin, hollow cells that contain no cytoplasm that transport water through the stem and root.
            1. Nerve cells have long slender axons that can carry nerve impulses over long distances.
              1. The ovum or egg cell is large so that it can carry food reserves for the embryo
                1. The sperm cell is mobile because of its tail. It has to travel from the vagina to the ovum
                  1. Red blood cells have no nucleus so that can have lots of haemoglobin and carry lots of oxygen
                    1. White blood cells can change their shape to engulf and destroy microbes
                      1. Bacterial cells consist of a membrane and cytoplasm surrounded by a cell wall. The cell wall isn't made of cellulose and there isn't a proper nucleus, the genetic material lies free in the cytoplasm
                        1. Yeast is a single-celled organism. Yeast cells have a nucleus, cytoplasm and a membrane surrounded by a cell wall.
                          1. Dissolved substances pass through cell membranes to get in and out of cells by using diffusion.
      2. Large multicellular organisms have developed systems for exchanging materials. Cells differentiate when they are being developed so that they can perform different functions.
        1. Tissues, organs and organ systems.
          1. Muscle tissue can contract to bring movement.
            1. Glandular tissue can produce substances such as enzymes and hormones
              1. Epithelial tissue covers all parts of the body (skin)
            2. An organ is made of different tissues that work together to do a certain job. The heart, lungs, kidneys and ovaries are all examples of organs.
              1. A stomach has muscular tissue to churn the contents
                1. Glandular tissue to produce digestive juices
                  1. Epithelial tissue to cover the outside and inside of the stomach
                    1. An organ system is a group of organs that perform a particular function.
                      1. There are many different systems in the body: circulatory system, digestive system, nervous system, reproductive system, respiratory system, skeletal system and urinary system.
                  2. The digestive system is an example of an organ system in which humans and other mammals exchange substances with the environment.
                    1. Glands produce digestive juices to break down food (the pancreas and salivary glands)
                      1. The stomach and small intestine is where digestion occurs
                        1. The small intestine is where the absorption of soluble food occurs
                          1. The large intestine is where water is absorbed from the undigested food, producing faeces
                            1. The liver is where bile is produced
                  3. Plants also have cells that are organised into tissues and organs
                    1. Plant organs include stems, roots, leaves and flowers
                      1. Epidermal tissues cover the plant
                        1. Mesophyll carries out photosynthesis
                          1. Xylem and phloem transports substances around the plant. The xylem transports water and salts, whereas the phloem transports food substances
                2. Photosynthesis
                  1. Green plants don't absorb food from the soil, they make their own using sunlight-This process is called photosynthesis and it occurs in the cells of green plants
                    1. Photosynthesis requires: light from the sun, CO2 from the air, Water from the soil and chlorophyll in the eaves
                    2. Two things are produced by photosynthesis: Glucose and oxygen
                      1. Glucose can be used to provide energy for respiration, used to produce oil or fat for storage, used to produce cellulose, used to produce proteins or converted into insoluble starch for storage
                        1. Photosynthesis can be limited by a: Low temperature, shortage of CO2, shortage of light.
                          1. At temperatures about 45 degrees, the enzymes controlling photosynthesis are destroyed, stopping photosynthesis
                          2. These limiting factors mean that plant growth can be controlled. E.G in greenhouses, plants can be encouraged to grow more quickly by increasing the temperature to 40 degrees, increasing CO2 levels and increasing light intensity
                      2. Organisms and their environment
                        1. Organisms may be distributed across a land, factors that affect this distribution are: Temperature, nutrients, amount of light, availability of water, oxygen or carbon dioxide
                        2. Proteins
                          1. Proteins have various functions in the body, they are structural components of tissues such as muscle, some hormones (insulin) are proteins, antibodies that form part of the body's defence system, are proteins, and enzymes are proteins.
                            1. Protein molecules are large molecules made up of long chains of amino acids, these chains are folded to produce a specific shape, which enables other molecules to fit into the protein.
                              1. Enzymes are biological catalysts; they increase the rate of reactions in an organism. The amino chain is folded into a 3-D shape which allows other molecules to fit into the enzyme
                                1. Different enzymes work best at different temperatures and pH levels. Temperatures about 37 degrees destroy most enzymes' special shape. Which is why it is dangerous for the body to go above 37 degrees.
                                2. Outside living cells, digestive enzymes are produced by specialised cells in glands in the lining of the gut.
                                  1. Enzymes pass out of the cells into the guy where they come into contact with food molecules
                                    1. Three enzymes (protease, lipase and amylase) are produced in four separate regions of the digestive system. They digest proteins, fats and carbohydrates to produce smaller molecules that can be absorbed.
                                3. Bile is produced in the liver and stored in the gall bladder before being released into the small intestine. It can be used to neutralise acid and emulsify fats in the body.
                                  1. Enzymes are used at home, protease is used in washing powders to break down stains such as food or blood. Lipase is used to break down oil and grease stains
                                    1. In industry, protease is used to pre-digest protein in baby foods, carbohydrases are used to convert starch into sugar syrup and isomerase converts glucose syrup into fructose syrup.
                                      1. Enzymes are also used as natural catalysts in industry.
                              2. Aerobic and Anaerobic Respiration
                                1. Aerobic respiration is respiration that takes place when oxygen is present. The oxygen combines with glucose molecules in cells to produce energy, this reaction is catalysed by enzymes.
                                  1. Aerobic respiration takes place inside the mitochondria. Aerobic respiration takes place constantly in a plant and animal cells and is extremely efficient.
                                    1. The energy released during respiration is used to build larger molecules using smaller ones. To enable muscles to contract. To maintain a constant temperature in colder surroundings and to make proteins in plants and animals from amino acids.
                                      1. During exercise, a number of changes take place. The heart rate increase, Arteries widen and rate and depth of breathing increases.
                                        1. The supply of oxygen and sugar is increased and removal of carbon dioxide speeds up. Glycogen stored in muscles is broken down to glucose to be used in respiration
                                      2. Anaerobic respiration happens if enough oxygen can't be supplied to the working muscles. Anaerobic respiration is the incomplete breakdown of glucose
                                        1. A waste product of anaerobic respiration is lactic acid, which builds up in the tissues and causes muscle fatigue. This means that the muscles stop contracting efficiently. Lactic acid is removed by the blood flowing through the muscles
                                  2. Cell Division and Inheritance
                                    1. Chromosomes are found in the nucleus, they are made of DNA and have a double helix structure. They contain genetic information in the form of genes. A gene is a section of DNA.
                                      1. Like all pairs of chromosomes, offspring inherit one sex chromosome from the mother and one from the father. The sex of an individual is decided by whether the ovum is fertilised by an X carrying sperm or a Y carrying sperm
                                        1. Mitosis is the division of body cells to produce new cells, it only needs one parent cell which produces an offspring that is identical to it
                                          1. Meiosis is sexual reproduction and requires two parent cells to produce an offspring with qualities from both parents
                                            1. When gametes join at fertilisation, one chromosome comes from each parent and a single body cell with new pairs of chromosomes is formed. This then divides by mitosis to form a new individual.
                                              1. Some characteristics are controlled by a certain gene. Each gene has different forms called alleles. E.G, the gene that controls whether you can roll your tongue or not has two alleles, you either can or you can't.
                                                1. In a pair of chromosomes, the alleles for a gene can be the same or different. If they are different, then one allele will be dominant and one will be recessive.
                                                2. Genotype refers to the alleles present, e.g one brown eye allele and one blue eye allele. Phenotype refers to the characteristic that shows itself e.g brown eyes.
                                                  1. When cells develop a specialised structure to carry out a specific function, this is differentiation. Many plant cells can differentiate through life. Animal cells differentiate at an early stage so quickly become muscle, nerves, etc.
                                                    1. Human stem cells are cells in human embryos and adult bone marrow, which have yet to differentiate. They can be made to differentiate into many different types of cells, e.g nerve cells to treat paralysis
                                                      1. Some genetic disorders are inherited. Embryos can be screened for the genes that cause genetic disorders. Polydactyly is where you have extra fingers or toes and is caused by a dominant gene. Cystic fibrosis is a disorder of cell membranes, caused by a recessive allele so it must be inherited from both parents.
                                          2. Body cells have 46 chromosomes arranged in 23 pairs. Gametes have 23 chromosomes (one from each pair). The fusion of gametes produces a zygote, that has 46 chromosomes
                                            1. Of the 23 pairs of chromosomes in the human body cells, one pair is the sex chromosomes. In females, these are identical and are called X chromosomes. In males one is shorter, the shorter is called the Y chromosome, the larger is the X
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