TAKS presentation for Spring 2007

Cells and organization of living systems

Organization of living systems

• All matter made of atoms• Atoms organized into molecules • Molecules organized into cells (Living things are

made of cells)• Cells organized into tissues• Tissues organized into organs• Organs organized into organ systems• Organ systems organized into organisms

Two types of cells

• Prokaryotic cells• Eukaryotic cells

Prokaryotic Cells• Lack nucleus and most

other organelles (structure within cell – performs specific function)

• Include Eubacteria and Archaebacteria

• Archaebacteria – ancient bacteria

• Eubacteria – true bacteria

• Good bacteria and pathogenic bacteria

Eukaryotic cells• Have nucleus and other organelles

Organelles in Eukaryotic cells• Nucleus – contains DNA; command center of cell• Mitochondria – found in all eukaryotes – breaks

down food molecules (i.e. – glucose) to release energy (cellular respiration) Equation for cellular respiration: C6 H12O6 + 6O2 6CO2 + 6H2O + ATP

• Ribosomes – where proteins are made• Endoplasmic reticulum – path along which molecules

move from one part of the cell to another• Golgi apparatus – processes and packages substances

produced by the cell

• Lysosome – digests molecules, old organelles, and foreign substances

• Cilia and flagella – propel cells through the environment; move materials over cell surface

• Vacuole – storage of water, waste, and/or enzymes• Microfilaments and microtubules – forms cytoskeleton of cell

for support, movement, and division of cells• Chloroplast – found in cells of plants and some protists – use

energy in sunlight to make the sugar glucose (photosynthesis). Glucose fuels all life’s processes (plant and animal).

• Cell wall – (plants) supports/protects cell

Plant and Animal cells

How cells keep themselves alive

• Maintain stable internal environment - homeostasis

Ways to maintain homeostasis

• Passive transport – no ATP used– Diffusion– Osmosis– Facilitated diffusion

• Carrier proteins• Ion channels

• Active transport – ATP used– Carrier proteins

• Cell membrane pumps (sodium-potassium)

– Endocytosis– exocytosis

Interdependence

• In multicellular organisms cells work together in organs and organ systems to help one another maintain homeostasis

Organ Systems• Circulatory – transports oxygen and nutrients to cells

and carries wastes away from cells• Respiratory – moves oxygen into the body and

carbon dioxide out of the body• Digestive – breaks down food and absorbs nutrients• Nervous – detects changes outside and inside your

body and controls the way your body responds to these changes

• Skeletal – movement, protection, shape, support, storage of minerals and produces blood cells

• Muscular – movement, posture, and production of heat

• Endocrine – produces chemical messengers called hormones; some hormones help to maintain homeostasis while others control development and growth

• Integumentary – forms protective barrier around body, prevents water loss, controls body temperature, and gathers information about your surroundings

• Immune – protects body from infection

• Lymphatic – takes fluid from the spaces between cells and returns it to the circulatory system; filters bacteria and other microorganisms from this fluid

• Reproductive – males – sperm production; females – eggs

• Excretory – removes wastes from the body and helps maintain homeostasis