Biology topic 1

• Levels of Cellular Organisation

  • Organism
  • Organ System
  • Organ
  • Tissue
  • Cell
• Cell


  The smallest structural and functional unit of an organism, which is microscopic and made of typically e.g. stem, muscles red blood, fat, cancer, nece
• Tissue


  A group of cells with similar structure and function working together to perform a specific function
• Tissue types


  • Neural
  • Adipose
  • Muscular
  • Glandular
  • Epithelial
• Organ


  A group of tissues working together to perform a specific function
• Organs


  • Heart
  • Lungs
  • Skin
  • Blood
  • Leaf
  • Foot
• Organ System


  Many organs working together to perform a specific function to carry out a particular role
• Organ Systems


  • Respiratory
  • Endocrine
  • Digestive
  • Excretory
• Cells are made from ORGANELLES
• There are about 1,000,000,000,000 cells in the human body
• Cell components


  • Nucleus
  • Cell wall
  • Cell membrane
  • Chloroplasts
  • Permanent vacuole
  • Mitochondria
  • Cytoplasm
  • Ribosomes
• Cytoplasm


  Place where most chemical reactions take place (reactions controlled by enzymes)
• Nucleus


  Contains the genetic material (DNA) which codes for proteins that control the activities of the cell
• Cell membrane


  Controls what enters or exits the cell
• Mitochondria


  Site of aerobic respiration (where most energy is released)
• Ribosomes


  Where protein synthesis takes place
• Cell wall


  Strengthens the cell, permeable, stops the cell from bursting
• Vacuole


  Storage of water and cell sap
• Chloroplast


  Surrounded by a membrane, contains pigment chlorophyll, absorbs light energy during photosynthesis, allowing plants to make their own food
• Specialised cells are designed for specific functions
• Specialised animal cells


  • Sperm cell
  • Nerve cell
  • Red blood cell
• Sperm cell


  • Nucleus carries the genetic material, but only half the DNA of a normal cell
  • Acrosome helps the sperm penetrate the egg's coats and join with it, has enzymes
  • Mitochondria produce energy for movement of the sperm and release energy for egg penetration
  • Flagellum (tail) provides movement so it can swim and find the egg cell
• Palisade cell

  • Chloroplasts help palisade perform photosynthesis, they absorb carbon dioxide during photosynthesis, and food, they make sugar (glucose) too
  • Palisade cells are towards the tops of leaves to absorb maximum sunlight, to produce glucose and oxygen
  • They are tall and have a large surface area to absorb CO2 and light
  • They have pigments, they contain chlorophyll which absorbs light energy and transfers it to the chloroplasts for photosynthesis
• Types of organisms


  • Multicellular eukaryotic
  • Prokaryotic - Single
  • Animals
  • Plants
  • Fungi
  • Protoctists
• EGG CELL


  • Half the genetic information than a normal body cell
  • Designed to be fertilised
  • Found in the Ovaries
  • Contains yolk which provides a large food store for the new cell
• NERVE CELL

  • Designed to carry electrical impulses
  • Has dendrites at each end and are very long
  • Can carry electrical impulses to different parts of the body
• RED BLOOD CELL


  • Designed to carry oxygen
  • Biconcave to increase surface area
  • Contains haemoglobin which joins with oxygen
  • Has no nucleus to maximise space for oxygen
• PALISADE CELL


  • Designed for photosynthesis
  • Tall and has a large surface area to absorb CO2 and light
  • Packed with chloroplasts to help make glucose
• ROOT HAIR CELL


  • Designed for absorption of water and ions
  • Has a large surface area which helps it to absorb water and minerals
  • Thin cell wall gives a short diffusion pathway, which makes it easy for substances to pass through
• CILIATED CELL


  • Designed to stop infection
  • They line the airways in the lungs
  • They have tiny hairs called Cilia
  • Hairs sweep away with trapped dust and bacteria back up the throat
• Binomial Nomenclature is used to give organisms their official scientific name
• This is used internationally to avoid confusion
• Binomial names tend to have Latin roots
• The first name is the genus


  With a capital letter
• Should always be written in italics
• Kingdoms


  • Animals
  • Plants
  • Fungi
  • Protoctists
• Eukaryotic organisms


  Cells have a nucleus and membrane-bound organelles, such as mitochondria & chloroplasts
• Prokaryotic organisms


  Cells do not have a nucleus or membrane-bound organelles
• Plant Kingdom


  • Gymnosperms
  • Conifers
  • Angiosperms (flowering plants)
• Gymnosperms


  • Strong seed made of woody tissue
  • Masses of needle-like leaves