Chapter 3 lesson 2 Life Science Presented by Mrs. Waterbury Paramecium

Life’s Organization Matter is made of atoms – Combined atoms = molecules Cells (living things only) are made of molecules Multicellular organisms can be made up of trillions of cells Cells working together enable organisms to function – cells have specific jobs Unicellular organisms (ex amoeba, algae) – one cell carries out all activities so it can survive (eat, eliminate waste, reproduce)

Types of cells Types of Cells: 1) prokaryotic – no membrane bound nucleus Smaller and have fewer cell structures Example: bacteria 2) Eukaryotic – have nucleus Specialized organelles Ex: all plant and animal cells (multicellular) and many unicellular organisms like algae and fungus

Cell Differentiation cells become specialized Fertilized egg Divides through mitosis These first cells can become any type of cell (stem cells) All the organisms info is contained in the DNA found in the chromosomes All cells contain all the info However different cells use different parts of the instructions –activates the part that codes for that cell’s specific functions

Animal stem cells Unspecialized cells that are able to develop into many different cell types Embryos – many stem cells Adults – fewer – used for cell repair and replacement Ex bone marrow – produce many types of blood cells Skeletal muscles – repair torn muscles

Plant stem cells - MERISTEMS Unspecialized cells grouped together Found in tips of roots and stems Cell division in these areas (mitosis) produces diff types of specialized cells

Cell organization Similar Cells working together to do a certain job form tissues 4 main types of animal tissues – muscle, connective, nervous, and epithelial

Animal Tissues Muscle – movement Connective – structure and support; connects other tissues Nervous – carries messages to and from brain Epithelial – protective layer – skin – lining of organs

Plant tissues Dermal – protection & helps reduce water loss Vascular – transports water and nutrients Ground – storage and support; where photosynthesis takes place

Organs Different tissues working together to perform a job - organs Ex stomach – specialized to break down food made up of all 4 tissues Muscle (contracts), epithelial (lines), nervous (sends message when full), connective (supports stomach wall)

Plant organs Leaves – job is photosynthesis – makes food Has all 3 plant tissues Dermal (covers), ground (produces food – site of photosynthesis), vascular (moves the food)

More organ systems Endocrine – (growth & homeostasis) – pituitary gland, thyroid, pancreas etc Respiratory – lungs, trachea, nose Urinary – kidneys, bladder, ureters, urethra Integumentary – protects – skin, hair, sweat glands Skeletal – bones, ligaments, cartilage

Organ systems Group of organs working together to complete a series of tasks Digestive - stomach, sm. Intestine, liver, and large intestine Circulatory – heart, arteries, veins Reproductive – ovaries, uterus, vagina, testes, scrotum, penis

Plant organ systems 2 major systems Shoot system – leaves, stems, and flowers Transports water and food Root system – anchors, and takes in water and minerals

Organisms Usually have many organ systems Systems work together so the organism can survive Organ systems depend on one another and can not function without the other

Cells differ in size, shape, and the jobs they do! Each cell has a job to do to keep the factory running properly! Cells depend on other cells.

Cell organization Cells working together to do a certain job form tissues Different tissues working together form organs Ex heart = blood, nerve, and muscle tissues Organs working together form organ systems

Sexual Reproduction Sex cells from two parents Fertilization – egg and sperm unite Fertilized egg - zygote Human cells have 46 chromosomes Horses have 60 Each kind of organism has a different number of chromosomes How many chromosomes does a sex cell have ? Egg Female Large Food materials Sperm Male Small –whiplike Head –almost all nucleus