Cells - the basic unit of living organisms; weren’t discovered until the invention of the m mm microscope (Anton van Leewenhoek). The Discovery of Cells

The term “cells” was a term coined by Robert Hooke as he studied the first cork cells. In fact, it was Hooke who coined the term "cells": the boxlike cells of cork reminded him of the cells of a monastery. The Discovery of Cells

Types of Microscopes: Light Microscope Light Microscope – uses a series of lenses to magnify objects (1500x) Electron Microscope Electron Microscope – uses a beam of electrons instead of light to magnify structures The Discovery of Cells

VIDEO Here Cells Intro

Cell Theory (Schleiden and Schwann contributed to these fundamental ideas) All organisms are composed of one or more cells. The cell is the basic unit of structure and organization of organisms. All cells come from preexisting cells. The Discovery of Cells

before nucleus true nucleus

The Discovery of Cells Two basic types of cells Prokaryotes Prokaryotes - cells that do NOT have membrane bound organelles. Eukaryotes Eukaryotes – cells that do contain membrane bound organelles like the nucleus, chloroplast, or mitochondria

What do cells really look like? Cardiac cells Red Blood Cells Nerve cells HIV Macrophage attacking a bacteria

Why are cells so small ?????

Why are cells so small?????   A single cell carries out all of the functions necessary for life, it takes in oxygen and gets rid of carbon dioxide and other wastes, it has to regulate its water absorption, take in food, move about, be sensitive to its environment and reproduce. The way a cell exchanges gases (oxygen and carbon dioxide) with the outside world is through diffusion. That means that the gases move into the cell if the concentration of the gas is lower in the cell than in the outside world and the opposite for gases moving out of the cell. This is fine for a small cell which has a large surface area to volume ratio so there is plenty of "surface" for the gases to move across. For large cells however this is not an efficient way of respiring as it takes far too long for gases to move across the cell membrane and deep inside the cell where it is needed.

The Plasma Membrane Survival of a cell depends the cell’s ability to maintain the proper conditions (homeostasis) within itself. plasma membrane The plasma membrane is a flexible boundary between the cell and its environment. selectively permeable The plasma membrane is selectively permeable, which means that only certain molecules can pass through.

Hydrophilic head Hydrophobic tails

VIDEO Here The Cell Membrane Cool animation

Parts of the Cell Ribosomes – site of protein synthesis, made up of rRNA Golgi apparatus – folded membranes that store and transports enzymes and hormones, also produces the cell wall in plants Cytoplasm – jelly-like material surrounding the nucleus of the cell Nucleus – The control center of the cell Nucleolus – Site of ribosome synthesis Nuclear Membrane – Surrounds the nucleus. Cell Membrane – Membrane surrounding the organelles and the cytoplasm of the cell.

Parts of the Cell Mitochondria – The site of cellular respiration or energy production. Membrane bound. Rough Endoplasmic Reticulum – forms a link between the nuclear membrane and the cell. Ribosomes are attached to the surface. Proteins are synthesized in the ribosomes and enclosed in vessicles and sent to the Golgi. Vacuole – Site of storage of glucose, water, salts, and toxic substances. Larger in plants cells than in animal cells.

Parts of the Cell Cell Wall – Plant, fungal, and bacteria have a cell wall that us used for support and protection. It is composed of cellulose. Chloroplast – Site of photosynthesis in the plant and algal cell. They are generally lens shaped and bound by a double membrane. Smooth Endoplasmic Reticulum – It forms a link between the nuclear membrane and the cell. Site of many metabolic reactions and synthesis of phospholipids and fatty acids.

Parts of the Cell Lysosome – Contain enzymes needed for digesting food, viruses, bacteria and old cells. Centrioles – Not normally found in plant cells. They are found in animal cells in pairs and are necessary for cell division.

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