The cell is the basic unit of living things. Cells & Heredity 1.1 The cell is the basic unit of living things.

I. Living things are different from nonliving things. Characteristics of Life Organization Enables organism to meet its needs Very simple (bacteria) or complex (kingfisher) Ability to develop and grow Ability to respond to the environment Pupils dilate, blinking Ability to reproduce

Needs of life Energy Almost all comes from the sun Food Materials Carbon dioxide, nitrogen, oxygen, water Living space

II. All living things are made of cells. Cells are the smallest unit of living things Unicellular Made of a single cell Too small to see directly

Multicellular Made of many cells Most of the organisms you see Contain specialized cells that work together to carry out the basic activities of life

Microscopes Led to the discovery of cells Instrument which makes an object appear bigger than it is

III. The microscope led to the discovery of cells. Robert Hooke Anton van Leeuwenhoek 1660s Named cells (looked like tiny rooms) Used 30x magnification Observed bark cells – dead cells 1670s Used 300x magnification Observed living cells in pond water

IV. Cells come from other cells. Cell Theory Every living thing is made of one or more cells. Cells carry out the functions needed to support life. Cells come only from other living cells.

V. The cell theory is important to the study of biology. Scientific theory Widely accepted explanation of things observed in nature Must be supported by evidence & observations Louis Pasteur Observed that spoiled milk contained bacteria Developed pasteurization to kill bacteria in milk Keeps milk fresher longer Disproved spontaneous generation The process of bacteria growing from nonliving materials

Pasteur’s Experiments Pasteur’s experiments showed that bacteria are present in the air. They do not grow spontaneously. -- End of flask is sealed. 1. Broth is boiled to destroy any living bacteria, and the flask is sealed. 2. A few days pass, and the broth is still clear. No bacteria have grown. 3. Two to three days pass, and the broth is still clear. No bacteria have grown. -- End of flask is broken. --Exposure to air is the variable. 1. Broth is boiled to destroy any living bacteria, and the flask is sealed. 2. The end of the flask is broken to expose the broth to the air. The broth is clear. 3. Two to three days pass, and the broth is cloudy because of the growth of bacteria.