Cell Structure and Function

KWL - The Cell What do you know? What do you want to know? What have you learned?

Explore Cells At your assigned lab table, draw the slide that you observe under the microscope. Write down any interesting details you would use to describe the slide. Be prepared to share your findings with the group.

Human Epidermis – Animal cells

Staphylococcus epidermis

Cardiac (heart) Muscle

Stems

Leaves

Amoeba proteus

Root tip

What are some similarities and differences that you observed by looking at a variety of cells?

Explain: Cells

History of the cell In 1665, Robert Hooke was the first to view cells from cork (dead plant material). He called them “cells” because they looked like tiny rooms. Anton van Leeuwenhoek saw tiny living organisms in water in 1675.

In 1838, Matthias Schleiden determined that plants are made up of cells. In 1839, Theodor Schwann determined that animals are made up of cells. In 1855, Rudolf Virchow concluded that new cells are produced from the division of existing cells.

The 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.

Types of Cells Two kinds of cells depending on whether they have a nucleus Prokaryote Eukaryote Genetic material

Prokaryotes Usually small and simple Genetic material (DNA) is not contained in a nucleus The ONLY prokaryotes in the world are BACTERIA.

Prokaryotic Cells

Eukaryotes Usually larger and more complex than prokaryotes. May be unicellular like an amoeba or multicellular like a plant Contain dozens of specialized structures called organelles. Includes protists, fungi, plants and animals.

Eukaryotic cell structure Two major parts:  Nucleus  Cytoplasm-portion of the cell outside the nucleus

Eukaryotic cells

Nucleus-The control center Function:  Contains almost all of the cell’s DNA for coding proteins and other molecules.  DNA is found on chromosomes which contain genetic information.

Nucleus-The control center Structure:  Surrounded by a double membrane called a nuclear envelope. It is dotted with many pores (holes) to allow materials (RNA, proteins, etc) in and out of the nucleus.  Small internal region called a nucleolus where ribosomes are made.

Ribosomes Function:  Site of protein assembly. Structure:  Small pieces of RNA and protein found throughout the cell.

Endoplasmic Reticulum Function:  Site where lipid parts of cell membrane are made, along with proteins and other materials to export from the cell. Structure:  Rough ER- has ribosomes on surface to assemble proteins  Smooth ER-NO ribosomes on surface

Golgi Apparatus Function:  Modify, sort, and package proteins and other materials from the ER for storage in the cell or release from the cell. It puts the finishing touches on proteins. Structure:  Stack of closely packed membranes

You have 3 minutes to compare your notes with a neighbor. Be sure to ask questions and fill in any blanks you may have in your notes at this time.

Lysosomes-The Clean Up Crew Function:  Breakdown of lipids, carbohydrates and proteins into small molecules to be used by the rest of the cell  Breakdown used up organelles  Get rid of all “stuff” in the cell Structure:  Small, filled with enzymes

Vacuoles - Storage Function:  Stores water, salts, proteins and carbohydrates Structure:  Sac-like  Plant cells have one large central vacuole  Animal cells have many small vacuoles

Mitochondria - Energy Function:  Convert chemical energy in food into materials easier for the cell to use. Structure:  Enclosed by two membranes with the inner membrane folded up.  Contains it’s own DNA (unlike other organelles) that is identical to your mother’s!

Chloroplasts – Energy in Plants Function:  Captures energy from the sun (solar energy) and changes it into food (chemical energy) for plants (photosynthesis) Structure:  Surrounded by two membranes  Contains own genetic information like mitochondria  Contains green pigment called chlorophyll  Not found in animal cells!

With your neighbor, list similarities and differences between mitochondria and chloroplasts. Be prepared to share with the class.

Cytoskeleton- structure and support Function:  Helps maintain cell shape  Helps with movement of the cell (i.e. flagella and cilia) Structure:  Two types: microfilaments and microtubules

Cell Membrane Function:  Regulates what enters and leaves the cell  Provides protection and support Structure:  Double membrane called a lipid bilayer  Flexible structure that forms a strong barrier between the cell and its surroundings

Cell Wall Function:  Provides support and protection for the cell Structure:  Lies outside the cell membrane  Found in plants, algae, fungi and many bacteria  NOT FOUND IN ANIMAL CELLS!

Individually, write down 3 differences between plant and animal cells.

KWL - The Cell: Your ticket out the door What do you know? What do you want to know? What have you learned? 1. Circle information that you heard in today’s notes 2. Asterik (*) next to questions you had answered today 3. Add new information learned