Cells and Tissues Chapter 3

Learning Objectives General Anatomy of a cell Three main regions of the cell and their structures and functions. Plasma Membrane structure and function Membrane junctions

Cells and Tissues Carry out all chemical activities needed to sustain life Cells are the building blocks of all living things Tissues are groups of cells that are similar in structure and function

Anatomy of the Cell Cells are not all the same All cells share general structures All cells have three main regions Nucleus Cytoplasm Plasma membrane

What are the three things all cells have in common? Question What are the three things all cells have in common?

The Nucleus Control center of the cell Three regions Contains genetic material (DNA) Three regions Nuclear envelope (membrane) Nucleolus Chromatin

The Nucleus

The Nucleus Nucleoli Nucleus contains one or more nucleoli Sites of ribosome assembly Ribosomes migrate into the cytoplasm through nuclear pores

The Nucleus Chromatin Composed of DNA and protein Present when the cell is not dividing Scattered throughout the nucleus Condenses to form chromosomes when the cell divides

Questions What is the overall function of the nucleus? What does the Nucleolus do? What is the chromatin? Where is it found?

Plasma Membrane Barrier for cell contents Double phospholipid layer Hydrophilic heads Hydrophobic tails Also contains proteins, cholesterol, and glycoproteins

Plasma Membrane

Plasma Membrane Specializations Microvilli Finger-like projections that increase surface area for absorption

Plasma Membrane Specializations Membrane junctions Tight junctions Impermeable junctions Bind cells together into leakproof sheets Desmosomes Anchoring junctions that prevent cells from being pulled apart Gap junctions Allow communication between cells

Plasma Membrane Specializations

Questions What is the structure of the plasma membrane? What are the three types of junctions in the plasma membrane and how are they different?

Cytoplasm Cytoplasm is the material outside the nucleus and inside the plasma membrane.

Cytoplasm Contains three major elements Cytosol Organelles Inclusions Fluid that suspends other elements Organelles Metabolic machinery of the cell “Little organs” that perform functions for the cell Inclusions Chemical substances such as stored nutrients or cell products

Questions What is the cytoplasm? What are the three major elements of the cytoplasm?

Cytoplasmic Organelles

Organelle/Structure Poster Project Design a poster that depicts your assigned organelle/structure. Include on the poster a Brief but accurate description of the function of the organelle/structure. Poster must include: Picture (DRAWN not printed out) Color Description of the function of the organelle. Worth 50 points (20 for the picture, 20 for the description and 10 for neatness and creativity). DUE TOMORROW!