Cell Structure and Function All living organisms are made up of: cells.

Cells are: The basic unit of structure and function of a living organism. Organisms can be either: unicellular Made up of only one cell multicellular Made up of many cells working together

History of the cell. 1665 Anton van Leevwenhoek: constructed first simple microscope. Viewed pond water and saw tiny moving structures he called “wee little beasties” .

1670 Robert Hooke English scientist and inventor of first compound light microscope. Viewed cork Named tiny, hollow units and called them “cells”.

Approximately 200 years later… 1833 Robert Brown First to view a nucleus within a cell. Scientist now knew that there were structures within the cell and that cells were not hollow like the cork.

1835 Two German scientist, Theodor Schwann (Zoologist) and Matthias Schleiden (Botanist) collectively came to the conclusion that all plants and all animals are made up of cells. 1855 Rudolf Virchow recorded that “all cells come from other like and pre-existing cells. Cell dividing hyperlink

The Cell Theory (based on the collective work of these 6 scientist) 1. Every living organism is made up of one or more cells. 2. Cells are the basic unit of structure and function of all living organisms. 3. All cells arise from like and pre-existing cells. Skin cells divide to create new cells for the healing process

Two types of cells exist: Prokaryotic and Eukaryotic Cells

Prokaryotic Cells Word means “before nucleus” Includes only and all bacteria Believed to be the first cells on Earth Basic traits: Lack a nucleus Lacks all membrane bound organelles. Genetic material just floats around the cytoplasm of the cell.

Eukaryotic Cells Word means “contains a true nucleus” Includes all animals, plants, fungi, and protist. Basic traits: 1.Evolved from prokaryotic cells.

2. Contains a nucleus 3. Contains membrane bound organelles. Organelles are “tiny organs” within a cell, each having their own function.

Because prokaryotic cells do not contain organelles they are generally much smaller than eukaryotic cells.

Since prokaryotic cells do not have organelles their size must be much smaller so materials, especially waste, can quickly exit the cell before it can poison the cell. Eukaryotic cells have organelles to contain the waste until it can exit the cell therefore the waste is not in danger of poisoning the cell.

Two types of eukaryotic cells: Animal like: Plant-like

Structures common to both Prokaryotic and Eukaryotic Cells (or in other words ALL cells)

Cell Membrane

Cell Membrane: (sometimes referred to as plasma membrane) Function: 1. Outer boundary of the cell -separates one cell from another

-regulates what is allowed to enter or leave the cell. 2. Acts as a “gatekeeper” -regulates what is allowed to enter or leave the cell. 3. Aids in protection and support. -keeps out bad things -provides some shape Oxygen, amino acids, glucose Water Carbon dioxide Cellular Waste Excess water

Cytoplasm: 1. -liquid part of the cell 2. –fills the internal volume of the cell 3.-made mostly of water with salts, amino acids, glucose, nucleotides, O2 etc… dissolved in it. Function: -to suspend and allow items and structures to move about in the cell.

Cytoplasm hyperlink What type of cell is this? Plant cell Eukaryotic or Prokaryotic? Eukaryotic

Bacteria Cell Prokaryotic or Eukaryotic? Prokaryotic

Cell Wall: 1.-surrounds the cell membrane -found in plants, fungi, bacteria and some protist. 2.-located outside the cell membrane 3.-provides shape and support Cell membrane Cell wall

4. -has openings so items can pass through. 5. -made up of cellulose/a polysaccharide humans can not digest.

Cell wall of a bacteria cell

Genetic Material: 1.-made up of DNA 2.-has instructions for making all cellular proteins these proteins go on to determine our traits.

-DNA contained in a nucleus -each linear pieces of DNA known as In Eukaryotic Cells: -DNA contained in a nucleus -each linear pieces of DNA known as chromosomes. -Humans have 46 chromosomes/cells -23 from your mom -23 from your dad

Nucleus: 1.-Known as the brain of cell 2.-It is the cells control center 3.-Contains the DNA 4.-Outside of nucleus is surrounded by another membrane 5.-contains pores for items to move in and out.

Nuclear Envelope or membrane: -outside of nucleus, contains with pores Nucleolus: -circular structure within nucleus -makes the ribosomes Nucleoplasm: -cytoplasm inside the nucleus

Genetic Material in Bacteria Bacteria are classified as being……… Prokaryotes Which means …………… They do not have a nucleus

The genetic material/DNA of a bacteria cell is just free floating around in the cytoplasm of the cell. Genetic material/DNA

Ribosomes The cells “workbench” Job: Makes proteins, in their linear form, by assembling amino acids in the correct order based on DNA’s code. -Ribosomes are made up of RNA and proteins. -Two types: 1. -Found attached to the endoplasmic reticulum or -Free floating in the cytoplasm Eukaryotic Prokaryotic