Unit 2: Cells and Systems

• Organisms (or living things) characteristics:

  • are made of cells
  • require energy
  • grow and develop
  • respond to the environment
  • reproduce
  • adapt to enviroment
• Structure VS function

  Structure: The body part that carries out the task

  Function: Does the specific task
• Each part of the body has an organ. The organs that make up each organ system work together to perform a certain task or function.

  
  

  Ex. The organs in the digestive system work together to break down the food to supply our body with nutrients
• Microscope: a scientific tool used to see small structures
• The cell is the basic unit of life. Each organism has at least one cell.
• Within each cell there are a number of specialized structures called organelles that carry out specific functions.
• Parts of Cells

  Nucleus: a “command centre” that directs all cellular activities such as movement, growth, and other life functions
• Parts of a Cell

  Mitochondria: the “powerhouses” of the cell where chemical reactions occur that convert the energy the cell receives into a form it can use
• Parts of a Cell

  Cell Membrane: a “controllable gateway” that lets needed materials in and waste materials out
• Parts of a Cell

  Vacuoles: the “storage rooms” where nutrients, water, or other substances can be stored by the cell. Plant cells have just one big vacuole, and animal cells have many small vacuoles.
• Parts of a Cell

  Cytoplasm: the “kitchen” of the cell. It contains the nutrients required by the cell to maintain its life processes.
• Parts of a Cell

  Cell wall: the “frame” of the cell. Found in plant cells but not in animal cells, it provides strength and support to plants.
• Parts of a Cell

  Chloroplasts: the “solar panels” of the cell. They are found in the cells of the green parts of plants. They carry out photosynthesis, converting the sun’s energy into food for the cell.
• Cell Diagram:

  A) Vacuole

  B) Nucleus

  C) Cytoplasm

  D) Cell Membrane

  E) Mitochondrion

  F) Animal

  
• Cell Diagram:

  A) Cell wall

  B) Cell Membrane

  C) Nucleus

  D) Mitochondrion

  E) Vacuole

  F) chloroplast

  G) Cytoplasm

  H) plant

  
• Some organisms can be single-celled (bacteria, micro-organisms, amoeba, paramecium) or multi celled (animals, plants)
• Diffusion: movement of particles from an area where there are more of them to an area where there are fewer of them.

  
• Osmosis is the diffusion of water particles through a selectively permeable membrane.

  
• Substances move in and out of cells by diffusion and osmosis.
• A selectively permeable membrane describes a membrane with very small openings that allow particles of some substances, but not others, to pass through. All cells have a selectively permable membrane.
• 4 types of Tissues

  • Connective
  • Epithelial
  • Nervous
  • Muscular
• Blood Cells:

  Red: carries oxygen to all cells of your body

  White: protects from and fights off infection
• Tissues

  Connective tissue: supports and connects different parts of the body. Blood is a connective tissue and so are fat, cartilage, bones, and tendons.
• Tissues

  Nervous tissue: makes up the brain, spinal cord, and nerves.
• Tissues

  Epithelial tissue: covers the surface of your body and the outside of your organs. It also lines the inside of some of your organs such as the intestine.
• Tissues

  Muscle tissue allows you to move. One type of muscle allows you to move your body. Cardiac muscle tissue pumps blood through your heart, and smooth muscle moves food along your intestine.
• Cells form tissues, tissues form organs, organs work together to form organ systems
• Systems

  The digestive system is in charge of breaking down the food you eat into parts small enough to be used by your cells.
• Digestion

  Mechanical: involves the physical breakdown of food into very small pieces.

  Chemical: involves the breakdown of large particles into smaller particles by substances called enzymes.
• Diaphragm Muscles

  When you inhale, these muscles contract, pulling your ribs up, and your diaphragm down. This increases the size of your chest and lungs, pulling air into your lungs. When you exhale, these muscles relax: your ribs go down and your diaphragm goes up. This decreases the size of your chest and lungs, forcing air out.
• Systems

  The respiratory system is responsible for supplying your blood with oxygen and removing the carbon dioxide from your blood and returning it to the air outside your body.
• Systems

  Circulatory system’s jobs is to deliver the nutrients absorbed by your digestive system to each cell in your body and is your body’s transportation network. Besides nutrients, it transports oxygen to your cells and remove waste products.
• The diffusion of nutrients and gases occurs in specialized blood vessels, located between arteries and veins, called capillaries.

  2 adaptations:

  • they are made of specialized epithelial tissue that is only one cell layer thick
  • they are very narrow so that the blood cells must pass through in a single file.
• Systems

  The excretory system does the waste removal.
• Systems

  Nervous system: monitors and respond to these stimuli.
• A neuron receives messages from small branches of the cell called dendrites . The incoming messages are passed from the dendrites through the cell body to the axon.

  
• The central nervous system is composed of the brain and spinal cord, while the peripheral nervous system is made up of the cranial (head) and spinal nerves. These nerves travel to all parts of your body.

  
• Parts of the Eye

  Retina: light hits retina and photoreceptors send the message to the brain.
• Rods: highly sensitive to light

  Cones: highly sensitive to colour
• Parts of an Eye

  Optic Nerve: Connects retina to the brain