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Unicellular and Multicellular Organisms. Two Types of Cells. Cells come in two flavours Prokaryotic and Eukaryotic Prokaryotic means “before a nucleus” Eukaryotic means “possessing a true nucleus” Prokaryotic cells have no nucleus while eukaryotic cells do have a nucleus.
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Two Types of Cells Cells come in two flavours Prokaryotic and Eukaryotic Prokaryotic means “before a nucleus” Eukaryotic means “possessing a true nucleus” Prokaryotic cells have no nucleus while eukaryotic cells do have a nucleus
Unicellular Organisms • Most are microscopic • Some unicellular organisms are prokaryotes – bacteria • Majority of unicellular organisms are eukaryotes :Amoeba, Paramecia • Perform the same tasks as multicellular organisms • They move, eat, reproduce and expel waste. • DO NOT perform specialized functions
Animal or Plant Like Animal-like protists are called protozoans ("first animals") because it is thought that they share the evolutionary history of animals. They share many common traits with animals. heterotrophs; they are unable to make their own food. Since they can’t make their own food they must be able to move through their environment and catch their food.
THE AMOEBA • blob-like organisms which move around by stretching out a part of their cytoplasm called a pseudopod (false foot) • feeds on smaller organisms by engulfing the organism in its cytoplasm - phagocytosis.
large protists which use small hairs called cilia to help with movement • paramecia use their cilia to pull food towards its oral groove where it is ingested. PARAMECIA
Animal or Plant Like • Plant-like protists are autotrophic; they can make their own foods • live in soil, on the barks of trees, in fresh water, and in salt water • very important to the earth because they produce an abundant amount of oxygen • These protists are similar to plants • contain chlorophyll and carry out photosynthesis • commonly called algae
plantlike protists whichare encased in two thin shells which are fused together. • These can be found in salt water and fresh water and contain chlorophyll to make their own food. Diatoms Commonly referred to as Alge
contain both plant and animal traits. • If there is a lot of sunlight, they are able to produce their own food like a plant. • If it is dark out at night time, they are able to ingest smaller organisms. Euglenas
Multicellular Organisms • Rely on a variety of cells to perform cellular functions. These are called “specialized cells”. • Specialized cells perform duties such as digestion or movement. • Example: Eyes, Muscles and Tongue. (what duties do these perform?) • Cells can be compared to small cities. Each one performs a different job/function. They all work together to be efficient. Just like we need specialist doctors, cells need specialist cells.
Question to Consider • Why do you think small cells are more efficient than large cells?
Cellular Process in Plants and Animals • Materials enter cells through diffusion and osmosis • Cells break down materials and convert them to energy, to transport energy from one place to another, to build protein and send chemical messages. • Cells also expel waste products. The higher number of cells, the more waste that is expelled.
Energy • Energy is necessary for digestion, transport, reproduction and repairing damage to cells • In animal cells, the mitochondria are responsible for breaking down carbs and releasing energy. • Specialized cells like liver and muscle cells have more mitochondria than other cells in the animal system. Why do you think this is? • In plant cells, chlorophyll convert energy to sugars using water, carbon dioxide and nutrients.
Processing and Transporting Main Cell Parts: Cytoplasm, Endoplasmic Reticulum, Golgi Apparatus, Lysosomes • Materials move through the cytoplasm • The Endoplasmic Reticulum creates protein from the materials and passes them to the Golgi Apparatus • The Golgi apparatus processes the protein and secretes them outside the cell to be used in other places. • Lysosomes break down food and digest waste.
Reproduction • Cells have a life span. Amoeba live for approximately 2 days. • Brain cells: 30-50yrs • Red Blood Cells: 120 days • Skin Cells – 20 days • New cells are created through cell division, when one cell splits into two. First the nucleus splits, and then the remainder of the cell. • The two new cells are identical. • In plant cells, the nucleus divides and then a new cell wall is created.
Do you Get It? • Consider the following question: A unicellular organism is a living thing that meets all of the basic needs with just one cell. A multicellular organism can require up to several trillion cells to do the same thing. Which do you consider to be more advanced? Explain your reasoning.
