Biology Unit 4 Notes #2 (Sections 3.2 – 3.4) Cell Structure Biology Unit 4 Notes #2 (Sections 3.2 – 3.4)

Cell Types With more advanced microscopes, scientists discovered that all cells can be grouped into two types: prokaryotic cells eukaryotic cells Most prokaryotic cells are unicellular organisms (bacteria) called prokaryotes. The genetic material in a prokaryotic cell is not surrounded by a membrane.

Cell Types Plants, animals, fungi, and protists are all made of eukaryotic cells and are called eukaryotes. In eukaryotic cells, the genetic material is surrounded by a membrane. Every eukaryotic cell has membrane-surrounded organelles, which have specialized functions and enable the cell to carry out different functions at the same time.

Review – Cell Types Which category of cells contain nuclei? How do prokaryotes and eukaryotes differ?

Basic Eukaryotic Cell Structure All cells take in food, rid waste, reproduce 3 main sections 1) Cell membrane 2) Cytoplasm 3) Nucleus 3 2 1

CO2 water 1. Cell Membrane Function: Controls the passage of materials into and out of a cell Double layer of phospholipids (bilayer) Semi-Permeable: only some materials may enter/exit oxygen

1. Cell Membrane 3 Parts Polar Head Nonpolar Tails phosphate Phospholipid Composition 3 Parts Polar Head 1) Phosphate Group 2) Glycerol Nonpolar Tails 3) Two chains of fatty acids Arrangement: Outside: Polar heads Inside: Nonpolar Tails glycerol Fatty acids

1. Cell Membrane Phospholipid Bilayer “Water-loving” “NOT Water-loving”

Review Name the 3 parts to a phospholipid? Which part(s) make up the head of a phospholipid? Which part(s) make up the tails of a phospholipid? Which part of phospholipid always seems to be in contact with a watery environment? Why?

2. Cytoplasm Jelly-like material inside of the cell Most organelles float within Nucleus Ribosomes Vacuoles Mitochondria Chloroplasts ER Golgi Body Lysosomes Job: Help dissolve solutes & move materials around

2. Cytoplasm The cytoskeleton, is found within the cytoplasm maintains the shape of an animal cell. The cytoskeleton is a network of threadlike proteins that are joined together.

2. Cytoplasm The cytoskeleton, maintains the shape of an animal cell.

3. Nucleus In most cells, the nucleus is the largest organelle. The nucleus is the part of a eukaryotic cell that directs cell activities and contains genetic information stored in DNA. EM Research Services, Newcastle Unersity

3. Nucleus DNA in the nucleus is organized into structures called chromosomes. The nucleolus is also contained in the nucleus and makes ribosomes, organelles involved in the production of proteins. The nuclear envelope is a porous, two-membrane structure that surrounds the nucleus.

3. Nucleus Job: Controls cell activity Inside: 1) Chromatin long strands of DNA holds info to make proteins 2) Nucleolus: makes ribosomes