Test biology 15 april 2024

• Cell structure and organization

  • All living things are made of cells
  • Unicellular
  • Multicellular
  • All cells have cell membrane
  • All cells have organelles

  
• Nucleus


  It contains the genetic information
• Ribosomes


  They make proteins
• Some organelles exist only in plant cells
• Vacuoles


  Present in all plant cells
• Cell types


  • Animal cell
  • Plant cell
• Cell specialization


  • In multicellular organisms groups of cells perform specific functions
• Tissue


  Group of similar and specialized cells performing a specific function
• Epithelium


  A tissue that covers a surface
• In leaves, palisade mesophyll cells are grouped in the leaves forming the palisade mesophyll tissue, with the function of photosynthesis
• Other specialized cells, without chloroplast form the tissue known as epidermis
• Organ


  Group of tissues working together to perform a specific function
• Organs


  • The small intestine
  • The leaf
• Organ system


  Group of organs with related functions working together to perform body functions
• Levels of organization


  • Organelle
  • Cell
  • Tissue
  • Organ
  • Organ system
  • Organism
• Eukaryotes


  Living organisms can be divided into these two large groups
• Prokaryotes


  • Surrounded by a cell membrane and a cell wall, some also have a capsule
  • Circular DNA free in the cytoplasm and small circular DNA pieces
• Viruses are not cells
• Cells are too small to be seen with the naked eye
• Most cell structures are transparent
• Magnification


  The image of a sample seen through a microscope is a magnified picture
• The actual size of the head of a sperm cell is 0.005 mm
• Cells and organelles are too small even for millimetres
• Tissue


  A group of similar and specialized cells that perform a specific function. Tissues can be further classified into four main types: epithelial, connective, muscle, and nervous.
• Organ


  A structure composed of two or more types of tissues working together to perform a specific function. An organ can be made up of several types of tissues, including epithelial, connective, muscle, and nervous tissues.
• Organ function


  The specific task or role that an organ performs in an organism. It is the result of the coordinated activities of the different types of tissues that make up the organ.
• Heart function


  The heart pumps blood throughout the body, delivering oxygen and nutrients to the cells and removing carbon dioxide and other waste products. It is able to perform this function because it is made up of several types of tissues, including epithelial, connective, muscle, and nervous tissues, that work together to contract and relax in a coordinated manner.
• Lungs function


  The lungs facilitate gas exchange between the body and the environment. They take in oxygen and expel carbon dioxide through the process of respiration.
• Liver function


  The liver detoxifies the body and produces bile to aid in digestion. It plays a key role in metabolism, synthesis, and storage of various biochemicals.
• Kidneys function


  The kidneys filter waste and excess fluids from the blood. They help regulate electrolyte levels and maintain the body's balance of fluids.
• Unicellular organisms


  Organisms that consist of a single cell and are able to carry out all of their life processes within that one cell
• Multicellular organisms


  Organisms that consist of many cells that are organized into tissues, organs, and organ systems that work together to perform specific functions
• Vacuoles


  Membrane-bound organelles found in plant and fungal cells, as well as some protists and animal cells that store water, nutrients, and waste products, regulate pH balance, and break down and recycle waste materials.