CELLS IN MULTICELLULAR ORGANISMS CELLS COMBINE TO FORM TISSUES AND ORGANS
Cells reproduce in multicellular organisms generally through mitosis & meiosis.
In unicellular organisms generally through binary division
SPECIALIZED CELLS:Cells that have specific structures that help them to perform particular functions
Specialization means that the cells of a multicellular organism must work together to support their own lives, as well as the life of the whole individual.
For example:
Red blood cells are small, pliable cells that have no nucleus and are specialized for carrying oxygen to all the cells of the body.
Do NOT reproduce the same way as other cells
How do RBC’s reproduce?
Bones in the skeletal system have marrow which produces red blood cells.
Animal Tissue
All cells in humans and animals can be categorized in four different tissue types Each organ is made up of different combinations of these 4 types of tissues: 1. Nervous tissue 2. Muscle tissue 3. Connective tissue
Blood, fat, tendon, bone, cartilage
Supports and connect
4. Epithelial tissue
‘blanket’ which covers the surface of the body and outside organs
Plant Tissue
Plant cells are also organized into tissues, but plants have 3 tissue types: 1) Photosynthetic/storage
Example: Inside of a leaf
2) Protective
Example: Outside portion of a leaf that is the waterproof layer
3) Transport- transportation of nutrients
Vascular tissues- connect roots to the leaves
Phloem tissue- specifically allows sugar to travel to the rest of the plant from leaves
Xylem tissue- specifically allows water to travel to the rest of plant from the roots
Organs in Plants
These tissues are organized into the 3 organs that make up plants:
Leaves
Roots
Stems
LEAVES ARE THE PLANT’S FOOD-PRODUCING ORGANS
Where photosynthesis takes place
Contains chloroplasts which are thin, allowing a large amount of light in
Contains stomata which are tiny opening that allow air to enter the leaf
Spaces between leaf cells allow the air to flow and the guard cells open and close the stomata
TRANSPIRATION: The loss of water in a plant which happens through evaporation
Not a problem unless the plant loses too much water and doesn’t replace it by the roots
Movement of water throughout the plant happens because of the differences in pressure - high pressure in the root hairs to lower pressure in the leaves
ROOT SYSTEM CONTAINS FINE ‘ROOT HAIRS’
If the soil water concentration is greater than root water concentration, water will flow inside of the root hairs, this is done by osmosis!
Water travels from cell to cell until it reaches the xylem tissue
The xylem cells move the water up the plant by a build up of highwater pressure (NOT OSMOSIS!) forcing water up the xylem tissues into stems and leafs
Organs and Organ Systems
ORGANS: Group of tissues that work together to perform a specific function ORGAN SYSTEM: Group of organs that work together to perform a certain task DIFFERENT TYPES OF ORGAN SYSTEMS IN US: