Cell Structure & Function

Cell Theory All living things are made up of cells. Cells are the smallest working units of all living things. All cells come from preexisting cells through cell division.

Definition of Cell A cell is the smallest unit that is capable of performing life functions.

Examples of Cells Amoeba Proteus Plant Stem Red Blood Cell Nerve Cell Bacteria

Two Types of Cells Prokaryotic Eukaryotic

Prokaryotic Do not have structures surrounded by membranes Few internal structures One-celled organisms, Bacteria

Eukaryotic Contain organelles surrounded by membranes Most living organisms PlantAnimal

“Typical” Animal Cell /~ acarpi/NSC/images/cell.gif

“Typical” Plant Cell

Cell Parts Organelles

Surrounding the Cell

Cell Membrane Outer membrane of cell that controls movement in and out of the cell Double layer

Osmosis –The cell membrane is Semipermeable = allows some materials to pass through, but not all. Osmosis =the movement of water from a solution of low solute concentration to a solution with high solute concentration

Diffusion is the movement of a substance (liquid or gas) from an area of higher concentration to one of lower concentration.

Cell Wall Most commonly found in plant cells & bacteria Supports & protects cells

Cell Wall

Flagella a tail-like projection that sticks out of certain cells, and functions in movement.

Cilia Hair-like structure that stick out from the cell. Used for movement.

Inside the Cell

Nucleus Directs cell activities Separated from cytoplasm by nuclear membrane Contains genetic material - DNA

Nuclear Membrane Surrounds nucleus Made of two layers Openings allow material to enter and leave nucleus

Chromosomes In nucleus Made of DNA Contain instructions for traits & characteristics

Nucleolus Inside nucleus Contains RNA to build proteins

Cytoplasm Gel-like mixture Surrounded by cell membrane Contains hereditary material

Endoplasmic Reticulum Moves materials around in cell Smooth type: lacks ribosomes Rough type (pictured): ribosomes embedded in surface

Ribosomes Each cell contains thousands Make proteins Found on ribosomes & floating throughout the cell

Mitochondria Produces energy through chemical reactions – breaking down fats & carbohydrates Controls level of water and other materials in cell Recycles and decomposes proteins, fats, and carbohydrates

Golgi Bodies Protein 'packaging plant' Move materials within the cell Move materials out of the cell

Lysosome Digestive 'plant' for proteins, fats, and carbohydrates Transports undigested material to cell membrane for removal Cell breaks down if lysosome explodes

Vacuoles Membrane-bound sacs for storage, digestion, and waste removal Contains water solution Help plants maintain shape

Chloroplast Usually found in plant cells Contains green chlorophyll Where photosynthesis takes place

Centrioles Only in animal cells!!! Aid in cell division.

Level of Organization LEVEL 1 - Cells Are the basic unit of structure and function in living things. May serve a specific function within the organism Examples- blood cells, nerve cells, bone cells, etc. LEVEL 2 - Tissues Made up of cells that are similar work together to perform a specific activity Examples - blood, nervous, bone, etc. Humans have 4 basic tissues: connective, epithelial, muscle, and nerve. LEVEL 3 - Organs Made up of tissues that work together to perform a specific activity Examples - heart, brain, skin, etc.

LEVEL4 - Organ Systems Groups of two or more tissues that work together to perform a specific function for the organism. Examples - circulatory system, nervous system, skeletal system, etc. The Human body has 11 organ systems - circulatory, digestive, endocrine, excretory (urinary), immune(lymphatic), integumentary, muscular, nervous, reproductive, respiratory, and skeletal. LEVEL 5 - Organisms Entire living things that can carry out all basic life processes. Usually made up of organ systems, but an organism may be made up of only one cell such as bacteria or protist. Examples - bacteria, amoeba, mushroom, sunflower, human

So remember… Cells make up Tissues Tissues make up Organs Organs make up Organ Systems Organ systems make up Organisms Cells Tissues Organs Organ Systems Organism