B7.5 New technologies The features of bacteria that make them ideal for industrial and genetic processes include: Rapid reproduction Presence of plasmids – circular DNA molecules that can be transferred easily between bacteria Simple biochemistry – easy to understand...
B7.4 What can we learn from natural ecosystems? In a perfect closed loop system no material enter or leave the system – waste products from one organism or process are used by another organism or process – the output from one part of the system becomes the input to...
B7.3 Peak performance – energy balance Homeostasis is the maintenance of a constant internal environment – it is achieved by balancing bodily inputs and outputs, while removing waste products. In order to maintain a constant body temperature, the heat produced within...
B7.2 Peak performance – circulation The HEART is a muscular organ in the circulatory system. It beats automatically, pumping blood around the body to provide cells with oxygen and dissolved food for RESPIRATION. Humans – and all other mammals – have a double...
B7.1 Peak performance – movement and exercise Vertebrates are animals that have an internal skeleton – those that do not have an internal skeleton are called invertebrates. In humans and other vertebrates, the skeleton has two functions: Support – the skeleton enables...
B6.3 Can reflex responses be learned? A reflex is an automatic response to a stimulus. Although they are not conscious actions, reflex responses to a new stimulus can be learnt by introducing the secondary (new) stimulus in association with the primary stimulus and...
B6.4 How do humans develop more complex behavior? The evolution of a larger brain gave early humans a better chance of survival – early humans could use tools, coordinate hunting and formulate plans about what might happen in the future. Having a larger brain meant...
B6.2 How is information passed through the nervous system? Nervous systems are made up of neurons (nerve cells) linking receptor cells (e.g. in eyes, ears and skin) to effector cells (in muscles/glands) Neurons carry impulses from one place to another, around the many...
B5.3 How do genes control growth and development within the cell? DNA is a nucleic acid in the shape of a double helix. Long strands of DNA make up chromosomes – these are found in the nucleus of a cell. DNA is a chemical code – our bodies need proteins for growth and...
B6.1 How do animals respond to changes in their environment Living organisms can detect and respond to a STIMULUS (a change in the environment of an organism such as light, temperature, etc.) RECEPTORS are stimulated by the stimulus and produce a rapid, involuntary...
B5.1 How do organisms develop Cells are the building blocks of all living things – multicellular organisms are made up of collections of cells. The cells can become specialised to do a particular job. Groups of specialised cells working together are called tissues and...
B5.2 How does an organism produce new cells? Mitosis and meiosis are two ways that cells reproduce MITOSIS is the process by which a cell divides to produce two new cells with identical sets of chromosomes to the parent cell – the new cells will also have all...
B4.3 How do living organisms obtain energy? All living organisms require energy released by respiration for some chemical reaction in cells – the energy is used for: Movement Synthesising (making) larger molecules Active transport Large molecules, such as starch and...
B4.2 How do plants make food? Photosynthesis can be written as There are three main stages in photosynthesis: ❶ Light energy is absorbed by the green chlorophyll ❷ Energy used to bring about the reaction between carbon dioxide and water to produce glucose (a...
B4.1 How do chemicals reactions take place in living things All living cells are made from basic units – these are called CELLS. The processes of life carried out by all living cells depend on chemical reactions within cells – these reactions need energy released by...
B3.2 How has life on Earth evolved? Life on Earth began around 3500 million years ago. ALL life on Earth, including all life that is now extinct, evolved from very simple living things- so all organisms share a common ancestor. However there is variation between...
B3.3 What is the importance of biodiversity? Organisms are classified into groups according to similarities and differences in characteristics including: Physical features (e.g. flowers in flowering plants and the skeletons in vertebrates DNA The groups start off...
B3.1 Systems in balance – how do different species depend on each other? A group of organisms that can breed together and produce fertile offspring is called a SPECIES. All things rely on their environment and other species to survive. The individuals in a species are...
B2.4 How do our bodies keep a healthy water balance? HOMEOSTATIS is the maintenance of a constant internal environment – It is achieved by balancing bodily inputs and outputs, using the NERVOUS SYSTEM and HORMONES to control the process. Examples if things that the...
B2.3 What factors increase the risk of heart disease? The HEART is a muscular organ in the circulatory system. It beats automatically, pumping blood around the body to provide cells with oxygen and dissolved food for RESPIRATION. The blood removes carbon...
B2.1 How do our bodies resist infection? MICROORGANISMS are organisms that are too small to see with the naked eye. They include BACTERIA, VIRUSES and FUNGI. They can be beneficial to us (e.g. the bacteria that live in our intestines can produce certain vitamins) or...
B2.2 What are vaccines and antibiotics and how do they work? VACCINATION involves exposing the body’s immune system to a weakened or harmless version of the pathogen in order to stimulate white blood cells to produce antibodies. If the body is re-infected by...
B1.4 How is a clone made? Clones are genetically identical individuals. Bacteria, plants and some animals can reproduce ASEXUALLY to form clones that are genetically identical to their parent. ASEXUAL REPRODUCTION only requires one parent, unlike sexual reproduction,...
B1.3 How can and should genetic information be used? How can we use our knowledge to prevent disease? Different forms of the same gene are called ALLELES. You inherit one allele for each gene from your father and one allele for each gene from your mother. For example,...
1.2 Why can people look like their parents, brothers and sisters but not identical to them? A human has 23 PAIRS OF CHROMOSOMES Parents pass on their genes to their offspring in their sex cells. A pair of chromosomes carries the same genes in the same...
B1.1 What are genes and how do they affect the way that organisms develop? A GENE is a short section of DNA. Genes carry instructions that control how you develop and function – they are long molecules of a molecule called DNA. Each gene codes for a specific protein...