Year 9 biology

• Tissues are groups of similar cells working together to perform specific functions.
• Cells are the basic unit of life that carry out all functions necessary to keep an organism alive.
• Mitochondria - releases energy from respiration
• Cytoplasm - where reactions happen in the cell
• Nucleus - contains DNA and controls the cells activity
• Ribosomes - where protiens are made (protein synthesis)
• Cell membrane - controls what goes in and out of the cell (permeable)
• Permanent vacuole - contains cell sap and keeps the cell turgid
• chloroplasts - contain chlorophyll, which has enzymes that absorbs light energy for photosynthesis
• Cell wall - strengthens the cell and supports the plant
• Nerve cell - They carry around impulses to the brain to enable us to respond to our effectors
• Muscle cells - they contract when stimulated by nerve impulse so we can move
• Root hair cell - found close to the root tip and has a large surface area for absorbing water and minerals
• Ciliated cell - A cell that has cilia, which are hair-like structures that move substances along the cell surface
• Cells - smallest unit of an organism. For example, in an animal cell there is a glandular cell and in a plant cell there is the Palisade cell
• Tissues - a group of cells with a similar function and structure which work together to do a particular job. For example for plants, leaf epithelium and for animals, stomach lining
• Organs - made up of different tissues working together to perform a specific task. For example, lungs or kidneys for animals and for plants, leaves.
• Organ systems - groups of organs working together to achieve a common goal. For example, respiratory system (lungs) or digestive system (stomach) and for plants, phtosynthetic system
• Organism - an individual plant, animal or single celled organism. For example, a daffodil and a human being.
• Animal and plant cells are examples of eukaryotic cells. Eukaryotic cells all have a cell membrane, cytoplasm, and genetic material enclosed in a nucleus.
• Bacteria are prokaryotic cells that are unicellular and have a cell wall. They may also contain extra small rings of DNA called called plasmids.
• A stem cell is an undifferentiated cell that has the potential to become lots of types of cells.
• Differentiation is the process of a cell becoming specialised for a particular reason
• Stem cells becoming Pluripotent means they can be made into everything, types of cells.
• Plants have meristematic stem cells and animals have embryonic and bone marrow stem cells.
• Agar is packed with nutrients and auxins
• Communicable disease are diseases that can be spread from one person to another. For example the common cold and measles.
• Non communicable diseases are diseases that cannot be passed from one person to another. For example cancer and diabetes
• Viruses can attack and damage all types of cells. The diseases they cause can be mild or potentially deadly. For example, HIV/AIDS and measles
• Bacterial diseases can affect animals and plants. For example, Salmonella food poisoning and gonorrhea (STD)
• Fungal diseases only affect plants. They can destroy crops and trees. For example, rust on wheat and powdery mildew on grapes
• Malaria is an example of a protist disease which is caught by parasites plasmodium, a eukaryotic cell which is carried by a mosquito.
• Human defense responces : skin - shield of armour, has interlocking skin cells. To get rid of pathogens, the skin sheds about every month. Your skin has glands of sebum (anti-microbal).
• human defense responses: nose - we have mucus in our noses. It is sticky which goes down to the stomach to be destroyed. The nose has hairs which trap the mucus.
• Human defense responses: Trachea and Bronchi - The trachea and bronchi has mucus and cilia (hairs) which trap and move microbes out of the lungs.
• Human defense responses: stomach - Produces acids which destroys microbes in the mucus that you swallow, the acids destroy mucus.
• Herd immunity is when a large proportion of a population is vaccinated, so that the disease cannot spread. This is because people get immune to the disease due to being vaccinated.
• Diffusion is the movement of particles from an area of high concentration to an area of low concentration until they are spread out evenly.
• Osmosis is the passage of weaker molecules from a weaker solution to a stronger solution through a partially permeable membrane.
• Partially permeable membrane is a membrane that allows some particles to pass through it but not all.