Cells Classification Prokaryote Eukaryote Cellular Components Organelle Structure

Cells Classification Prokaryote & Eukaryote Cellular Components Organelle Structure & Function

Classification All living things can be classified into: Prokaryote Eukaryote Archaebacteria Bacteria (Monera) Protista Fungi Plantae Animalia Pro = before, Eu = after, Karyon = nucleus

Prokaryote and Eukaryote Prokaryote Eukaryote Genetic Material 1 circular chromosome Not enclosed (nucleoid region) +1 chromosome, linear Enclosed by a membrane (nucleus) Evolution 3. 5 billion years ago 1. 5 billion years ago Cell size Body form Smaller unicellular Larger Uni & multicellular Reproductive strategy Asexual and sexual Oxygen requirement Anaerobic Aerobic Organelles Absent Present

Cellular Components w w w Outer protection Cell control center Energy control center Cell processing Storage & waste Structural support & movement

Organelle w Structures that perform specialized functions in cells w “mini organs” w How many organelles can you name?

Plasma Membrane Structure w Mainly composed of phospholipids w Surrounds cytoplasm (gel-like material containing mainly water and dissolved materials) Function w Controls exchange of material between interior of the cell and the external environment w Protection

Cytoplasm w Gel-like material made up of water and dissolved minerals where the organelles are suspended w Contains the cytoskeleton

Cytoskeleton w w “Skeleton” of cell - gives shape Organizes location of organelles Allows movement of cell parts Network of interconnected fibers that can be assembled and disassembled

Cell Wall Structure w Composed of cellulose Function w Gives shape and rigidity to prokaryotic and plant cells w Protection

Control Centre Nucleus w Contains genetic information & nucleolus w Control center of cell w RNA synthesis Nucleolus is a darker area in the nucleus where ribosomes are made Nuclear envelope is a Nucleoid region double layered membrane w Contains genetic information but is perforated by nuclear not surrounded by a membrane pores (allow RNA to exit) w Only in prokaryotes

Ribosomes w Ribosomes – 2 subunits, composed of both protein and RNA, made in nucleolus, can be bound to ER or float freely in cytoplasm w Ribosome – structures that catalyze the reactions of protein synthesis w Like the workers of the cell

w Lacks a membrane w Involved in organizing spindle fibers during cell division, site for production of microtubules w Animal cells contain a pair of centrioles (made of cylindrical tubes) Centrioles

Endoplasmic Reticulum Structure w Cisternae: flattened, interconnected membranes sacs w Branches out from the nuclear envelope w RER – ribosomes w SER – no ribosomes Function w RER – site for protein synthesis w SER – site for lipid synthesis

Golgi Apparatus Structure w Flattened, stacked, interconnected membrane (cisternae) w Located near ER Function w Modifies proteins and lipids w Packages products into vesicles for transport w Fate of products: (a) Export - outside cell (b) Plasma membrane surface (c) Cytoplasm (d) Other organelles

w Energy production center (aerobic cellular respiration)

Chloroplast w Site for photosynthesis by trapping light energy w Gives plant green colour due to chlorophyll pigment w Starch storage

Vacuole, Lysosome, Vesicle w All membrane bound sacs w Vacuole – fluid-filled sac used for storage of food, water, waste etc. , most prominent in plants where it is also used to maintain turgor pressure w Lysosome – contains degradative enzymes involved in hydrolytic actions w Vesicle – transport vehicles

Cilia & Flagella w Flexible projections that extend outward from the cell w Cilia are short hair-like extensions (often used to propel food) w Flagella is a long tail-like whip w Movement requires energy

Summary of Differences Prokaryote Outer protection Control centre Energy centre Storage Plant Animal

Summary of Differences Prokaryote Cell wall Outer protection PM Control centre Energy centre Storage Plant Cell wall PM Animal PM

Summary of Differences Prokaryote Plant Animal Cell wall Outer protection PM Cell wall PM PM Nucleoid region Nucleus Control centre Energy centre Storage

Summary of Differences Prokaryote Plant Animal Cell wall Outer protection PM Cell wall PM PM Control centre Nucleoid region Nucleus Energy centre Chloroplast Mitochondria Storage

Summary of Differences Prokaryote Plant Animal Cell wall Outer protection PM Cell wall PM PM Control centre Nucleoid region Nucleus Energy centre Chloroplast Mitochondria Cytoplasm Large central vacuole Many smaller vacuoles Storage