Characteristics of Living Things What does it mean to be ALIVE? August 26th/27th, 2008

Living things share the following characteristics: are made up of units called cells. reproduce. are based on a universal genetic code. grow and develop. obtain and use materials and energy. respond to their environment. maintain a stable internal environment.

Activity Is Sammy Alive? You will be given a worksheet that contains several different scenarios about a boy. At each stage of his life (each scenario) comment on whether or not you feel like he is still “alive”. After all the scenarios, you will make a final decision on whether or not you feel like Sammy is alive, and if not, when it was when he was no longer alive. You will have 1 minute – after the scenario is read – to write down your opinion and justification.

Cells An Introduction

What is a cell? 1. A cell is the basic unit of all forms of life. 2. A collection of living matter enclosed by a barrier that separates the cell from its surroundings

Cork Cells

Amoeba

Onion Cells

Red Blood Cells

Plasma Cells

Schwann Cells

Epithelial Cells

Liver Cells

Stem Cells

Sperm Cells

Egg Cells

Cell Theory All living things are composed of cells. Cells are the basic units of structure and function in living things. New cells are produced from existing cells.

Activity Using a Microscope to See Different Types of Cells

Daily Review All living things share many characteristic in common, for example, all living things are made up of functional units called cells. A cell is the basic unit of all forms of life, and all its parts are surrounded by a barrier that separates it from the outside world. The cell theory states that; all living things are composed of cells (produced from existing cells), which are the basic units of structure and function in living things.

Cell Structure and Function August 28th/29th 2008

Not all cells are the same! Similarities among cells! Cells come in a variety of shapes and sizes but they have two things in common: 1. They are surrounded by a cell membrane that acts as a barrier with the environment 2. They contain DNA- the molecule that carries biological information

Differences! One difference between cells is the presence or absence of organelles.

Viruses Viruses are not considered cells. Viruses are not even considered to be alive. They are simply small particles made up of three different macromolecules: nucleic acids, protein, and sometimes, lipids.

Two Cell Types Organisms whose cells lack a nucleus Category Definition Examples Prokaryotes Organisms whose cells lack a nucleus Bacteria Eukaryotes Organisms whose cells contain a nucleus Plant cells Animal cells Fungi Protists

Prokaryotes Eukaryotes

Reflection Write your answers in COMPLETE sentences What is one similarity between cells? What is one difference between cells? List the two main types of cells and give an example of each.

Eukaryotes Structure and Function Cell Membrane A thin, flexible barrier around a cell. It regulates what enters and leaves the cell.

Eukaryotes Cell Wall The strong, supporting layer around the cell membrane in plants, algae, and some bacteria.

Eukaryotes Organelle A specialized structure that performs important cellular functions within a eukaryotic cell.

Eukaryotes Cytoplasm The material inside the cell membrane that surrounds all the organelles.

Eukaryotes Nucleus The structure that contains the cell’s genetic material (DNA) and controls the cells activities.

Eukaryotes Nucleolus The small, dense region inside the nucleus where the assembly of proteins begins.

Eukaryotes Nuclear Envelope A layer of two membranes that surrounds the nucleus of a cell.

Reflection Write your answers in COMPLETE sentences What is the main difference between plant an animal cells? What substance surrounds the organelles in a cell? Where is the genetic material in a cell found?

Exit Slip Write your answers in COMPLETE sentences What is one difference between cells? List the two main types of cells and give an example of each. Why is a virus not considered to be a cell? Based on the definition of “organelle”, is the cytoplasm considered an organelle? Why or why not?

Daily Review

Eukaryotes Ribosome A small particle in the cell, on which proteins are assembled. It is made up of a combination of RNA and protein.

Eukaryotes Endoplasmic Reticulum Includes smooth and rough ER. The site in a cell where lipid (fat) components of the cell membrane are assembled and proteins are modified (changed).

Eukaryotes Golgi Apparatus A stack of membranes in the cell that modifies, sorts, and packages proteins from the ER.

Eukaryotes Lysosome A cell organelle filled with enzymes needed to break down and digest certain materials in the cell, such as food particles.

Eukaryotes Vacuole A cell organelle that stores materials such as water, salts, proteins, and carbohydrates.

Eukaryotes Mitochondria A cell organelle that converts chemical energy (food) into energy that the cell can use.

Eukaryotes Chloroplast An organelle found in the cells of plants that captures the energy from sunlight and converts it into chemical energy (food).

Reflection Write your answers in COMPLETE sentences Where are proteins created in a cell? What other two structures must a protein passes through before it can leave the cell? Which organelle “eats” for the cell? Compare and contrast mitochondria and chloroplasts.

Exit Slip See half sheet.