CELL ORGANELLES & FEATURES Chapter 7, Section 3

Think, Pair, Share Name at least 3 organs in your body and body and how they help you survive (Fill in #’s 1,2,3 on your sheet). How are organelles in a cell like organs in your body?

PLASMA MEMBRANE (p.175) Membrane Lipids Membrane Proteins Cholesterol (lipid) in animals prevent membrane freezing in low temps

Phospholipid Bilayer = designed so that the fatty acid tails (the part that doesn’t like water) are in the middle and the phosphate group heads (the part that likes water) face the inside & outside of the cell

1. Integral Proteins = proteins embedded in membrane Membrane Proteins 1. Integral Proteins = proteins embedded in membrane Surface markers Receptors for chemical signals Transport Proteins = move substances & waste materials through the plasma membrane 2. Peripheral Proteins = lie on one side of membrane, not embedded

Fluid Mosaic Model Phospholipid Bilayer behaves more as a fluid rather than a solid Proteins & Lipids can move laterally Constantly changing “mosaic” pattern Membrane is selectively permeable, letting only certain materials in & out http://www.susanahalpine.com/anim/Life/memb.htm

Think, Pair, Share 3. What is in the nucleus of the cell and why is it so important?

NUCLEUS & CELL CONTROL (P.180) Nucleus = houses and protects cell’s genetic info/blueprints, DNA Chromatin = period of non-division DNA in a threadlike form Chromosomes = during division DNA condenses

Nuclear Envelope = 2 lipid bilayer membranes surround nucleus covered with nuclear pores (allows RNA in and out) Nucleolus = concentrated DNA, area within nucleus, where ribosomes are made Ribosomes = site of protein production Cytoplasm = fluid cytosol and organelles

Assembly, Transport , & Storage (p.181) Organelles are suspended within the cell’s cytosol

ENDOPLASMIC RETICULUM Site of cellular chemical reactions Series of folded membranes, folding allows it to better fit in a small space 2 types, rough & smooth

1. Rough ER 2. Smooth ER Covered with Ribosomes Produces proteins & phospholipids (makes digestive enzymes) 2. Smooth ER Lacks ribosomes Builds lipids (cholesterol, estrogen, testosterone)

GOLGI APPARATUS System of flattened, membrane sacs Modifies proteins Packages proteins in vesicles to be sent to other locations in the cell Vesicles get modified as they travel through Golgi apparatus

VACUOLES Vacuole = compartments for storage (food, enzymes, etc.) Vacuoles are mainly found in plant cells

LYSOSOMES Lysosome = organelles containing digestive enzymes Digest worn out organelles, food, viruses & bacteria

Energy Transformers (p.184)

CHLOROPLASTS Found in plants A type of plastid Chlorophyll = green pigment in chloroplasts, traps light energy to be converted into chemical energy

MITOCHONDRIA Organelles that transfer energy from organic molecules to ATP ATP = adenosine triphosphate, stores energy in structure

Highly active cells (muscle cells) have more mitochondria Has 2 membranes Outer Membrane = separates mitochondria from cytosol Inner Membrane = shaped into folds to fit in a small space, where chemical reactions to produce energy occur

Think, Pair, Share 4. Compare mitochondria and chloroplast. 5. Contrast mitochondria and chloroplast. 6. Which cells contain mitochondria? 7. Which cells have chloroplasts?

Organelles for Support & Locomotion (p.185)

CYTOSKELETON Network of tubes & filaments crisscrossing cytosol Gives shape to cell Acts as “highway system” to move materials throughout the cell Microtubules = thin, hollow cylinders made of protein Microfilaments = smaller, solid protein fibers

Cilia & Flagella = hairlike structures, extend from cell body, movement Centrioles = 2 short cylinders of microtubules, found in animal cells, organize microtubules during cell division