Chapter 3 lesson 2

Life Science

Presented by

Mrs. Waterbury

Paramecium

Life’s Organization

Matter is made of atoms – Combined atoms = moleculesCells (living things only) are made of moleculesMulticellular organisms can be made up of trillions of cells Cells working together enable organisms to function – cells have specific jobsUnicellular 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 nucleusSmaller and have fewer cell structuresExample: bacteria2) Eukaryotic – have nucleusSpecialized organellesEx: all plant and animal cells (multicellular) and many unicellular organisms like algae and fungus

Cell Differentiationcells become specialized

Fertilized eggDivides through mitosisThese first cells can become any type of cell (stem cells)All the organisms info is contained in the DNA found in the chromosomesAll cells contain all the infoHowever 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 typesEmbryos – many stem cellsAdults – fewer – used for cell repair and replacementEx bone marrow – produce many types of blood cellsSkeletal 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 tissues4 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 lossVascular – transports water and nutrientsGround – storage and support; where photosynthesis takes place

Organs

Different tissues working together to perform a job - organsEx 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 etcRespiratory – lungs, trachea, noseUrinary – kidneys, bladder, ureters, urethraIntegumentary – protects – skin, hair, sweat glandsSkeletal – bones, ligaments, cartilage

Organ systems

Group of organs working together to complete a series of tasksDigestive - stomach, sm. Intestine, liver, and large intestineCirculatory – heart, arteries, veinsReproductive – 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 tissuesDifferent tissues working together form organsEx heart = blood, nerve, and muscle tissuesOrgans working together form organ systems

Sexual ReproductionSex cells from two parentsFertilization – egg and sperm uniteFertilized egg - zygoteHuman cells have 46 chromosomesHorses have 60Each kind of organism has a different number of chromosomesHow many chromosomes does a sex cell have ?

Egg

Female

Large

Food materials

Sperm

Male

Small –whiplike

Head –almost all nucleus

http://www.digitalcurriculum.com/