Cell Structure and Function

Lesson Objectives Understand the Differences Between Prokaryotes and Eukaryotes Be able to recognize and define the parts and purpose of basic cellular machinery

Vocabulary Prokaryotes Eukaryotes Cell Membrane and Cell Wall Nucleus Cytoplasm Organelle Vacuole Ribosome Endoplasmic Reticulum Golgi Apparatus Mitochondria and Chloroplasts Cytoskeleton Microfilaments and Microtubules Passive Transport Osmosis Active Transport Molecular Transport Bulk Transport Endocytosis and Exocytosis

The Cell is the Basic Unit of Life Cells are VERY tiny units of life. Cannot be seen without a microscope First discovered by lens maker Robert Hook examining cork First Single Celled Organisms discovered by Anton van Leeuwenhoek Some organisms are single cell, some are multicellular

Prokaryotes –vs- Eukaryotes Older than Eukaryotes No nucleus Simpler Form Single celled life Eukaryotes: More complex DNA contained in Nucleus Single Celled Life Multicellular Life

The Cell is a Factory Cells move chemicals, compounds, and enzymes around their interiors, and then export the products to provide for the functions of life!

The Control Center – The Nucleus Houses the DNA ; The master instructions for the body Selectively permeable. Some stuff allowed out….very little allowed in. Allows RNA (Temporary Copies of DNA) to pass out in order to carry out instruction Present in Eukaryotic Cells only Small dense region called “nucleolus’ houses the DNA DNA twisted up into coils called ‘chromatin’

The Space - Cytoplasm The liquid space between the parts Water based, full of all kinds of stuff Compounds move through the cytoplasm on their way to their final destination Very busy place, full of: Proteins Sugars Enzymes Toxins Fats Nucleotides

The Assembly Lines - Ribosomes Proteins are built here from amino acids Stuck together piece by piece from 20 different amino acids Ribosomes ‘translate’ the genetic message Based on the DNA sequence, different proteins will be built When protein is finished, it is cut loose and sent on its way to the Golgi Apparatus

The Packaging Line – The Golgi Bodies ‘Boxes up’ the proteins for travel Tags them with chemicals that help move them to the proper destination Flat, membranous shape Vesicles ‘pinch off’ from the Golgi apparatus

The Conveyor Belts – Vesicles and Vacuoles Some proteins/compounds are fragile, and need to be packaged for transport. Some compounds are harmful, and need to be kept away Vesicles protect important compounds and get them where they need to be. Sometimes outside of the cell Sometimes inside of the cell Called vacuoles in plant cells Allows for transport and excretion

The Power Plant – The Mitochondria nad Chloroplasts The bulk of energy production in organisms happens here LOTS of chemistry going on, that we will get into in the future Animals have mitochondria, which perform ‘cellular respiration’ Plants have chloroplasts which perform ‘photosynthesis’ Energy for life must be in an ‘available form’

The Internal Supports - Cytoskeleton Composed of protein filaments that give the cell shape Microtubles – Hollow tubes that flex and bend Microfilaments – Solid struts that stretch Which has a stronger cytoskeleton? Bone cells? Skin cells? Which are more flexible? Muscle Cells?

The Fence – Cell Membranes and Cell Walls Formed from a ‘lipid bilayer’ 2 layers of lipid molecule Water loving end Water hating end Allows cell to maintain an internal environment Also allows molecular pass through

Passive Transport – Diffusion and Osmosis Molecules will spontaneously go from areas to higher concentration to areas or lower concentration. No energy input required Osmosis – Molecules move through a surface that only allows one type of molecule through. Selectively permeable

Active Transport – Molecular Transport and Bulk Transport