Cell Structures

Cell Structures

Barriers…  Cell Wall Plants & prok. (not animals) Plants & prok. (not animals) Structural (plant support) & protective role Structural (plant support) & protective role Cellulose in plants Cellulose in plants Freely permeable Freely permeable

Cell walls of onion skin…

Barriers… Cell Membrane (plasma membrane) In ALL cells Support/protection Regulates movement in/out of: Regulates movement in/out of:WaterNutrients Waste products

Cell Membrane...

Barriers… Nuclear Envelope (nuclear membrane) Surrounds nucleus Thousands of pores Material move in/out, incl. RNA

Nuclear envelope

Fluids… Cytoplasm (cytosol) Bet. cell mem. and nuclear env., site of most chemical activity Nucleoplasm Semi-fluid medium of nucleus Protoplasm Term used for all substances inside cell

The Control Center The Nucleus

The Nucleus… Controls most cell processes Contains Chromatin DNA bound to proteins During cell division, condenses to Chromosomes… Has a Nucleolus Small, dense region Assembly of Ribosomes Nuclear Envelope (or membrane)

Little Organs assist the cell in conducting reproductive, respiratory, and structural needs Organelles of the cytoplasm

Cytoskeleton…  Protein filaments  Maintains cell shape  Involved in cell movement

Cytoskeleton

Mitochondrion… Uses energy from food Makes high-energy compounds (ATP) needed for Rx elsewhere.

Ribosomes… Small, made of RNA (is an RNA molecule) Assembly of proteins Free in cytoplasm or attached to Rough ER

Endoplasmic Reticulum…  Large, assists with other organelle movement  Two types: Rough ER (RER) Rough ER (RER) ○ Ribosomes stud surface ○ Aids in synthesis and modif. of proteins ○ Found wrapped around nucleus, extending into cytosol Smooth ER (SER) Smooth ER (SER) ○ No ribosomes, attached to distal RER ○ Synthesis of lipids, phospholipids, steroids (Plentiful in testes, ovaries, skin oil glands) (Plentiful in testes, ovaries, skin oil glands)

Golgi Apparatus… Receives proteins from rough ER Enzymes attach carbs and lipids to the proteins Can store proteins until needed Proteins then sent to final destination (within cell or outside – exocytosis) PACKAGING and SHIPPING

Golgi Apparatus

Vacuoles… Saclike structure Stores water, salts, proteins, carbs Can be large in plant cells Helps in plant support by keeping turgor pressure high

Vacuoles

Vacuoles Korotnovella, an amoeba. Inside this cell we can see a nucleus near the center with a rather angular dark nucleolus, various food vacuoles, and a clear round contractile vacuole at about 10 o'clock.

Lysosomes… Filled with enzymes (like H 2 O 2 ) Breaks down lipids, carbs, and proteins from food old organelles debris and harmful invaders

Video

Plastid 1: Chloroplasts… In plants, not animals or fungi Uses sunlight to make energy rich food mol. thru photosynthesis (psyn)

Chloroplasts…

Chloroplast

Plastid 2: Leucoplast Sometimes called amyloplast; stores starch (amylose)

Plastid 3: Chromoplast Stores pigments in plants

Centrioles Cylindrical; group of microtubules In animal cells, used in cell division As “basal bodies,” form cilia and flagella

Cell membrane - Structure  A phospholipid contains- one head; negatively charged phosphate group that is hydrophilic (water-loving) one head; negatively charged phosphate group that is hydrophilic (water-loving) two tails of fatty acid chains that are hydrophobic (water fearing) two tails of fatty acid chains that are hydrophobic (water fearing)

The Cell Membrane Made of a phospholipid bilayer regulates what passes in/out Supports and protects Selectively permeable – only certain things pass through. 5 nm thick

Cell membrane features The fluid mosaic model fluid in nature  cell mobility Within mem. are various proteins for : enzyme activity, cell attachment, communicating with other cells, Trans. of substances in and out