1. Cell structure
Lecture 2

2. Cell Membrane – all cells
FUNCTION- The cell membrane regulates what enters and leaves the cell and also provides protection and support
Takes in water and food and eliminates waste
STRUCTURE - The membrane is a double-layered sheet called a lipid bi-layer
Polar heads face outwards and non-polar tails face inwards
Embedded in the membrane are protein channels/pumps and carbohydrates

3. B. Cell Wall – plants and bacteria
Where is it found?
Found in almost all prokaryotes
Found in plants, fungi, and algae
NOT found in animals
Lies outside of the cell membrane
Allow for movement of certain molecules
Water, carbon dioxide, oxygen and some other substances
The main function of the cell wall is to provide support and protection to the cell
Structure - Cell walls are made of carbohydrates i.e. cellulose fiber

4. Nucleus - eukaryotes
Function - The nucleus controls most cell processes and contains the hereditary information of DNA
Structure - Consists of 4 parts
Nucleolus – small densely packed region where ribosomes are created
Nuclear Envelope – double membrane layer surrounding the nucleus
Nuclear Pores – a perforations within the nuclear membrane
Chromatin – this is the granular material within the nucleus
Chromosomes – the condensed form of chromatin just before a cell divides

5. Cytoskeleton – all cells
Function - A network of protein filaments that helps the cell keep its shape, also used in many forms of cell movement (in the documentary the virus traveled along these filaments)
Structure - Made up of microtubules and microfilaments

6. Ribosomes - eukaryotes
Function -Ribosomes assemble proteins following the coded instructions that come from the nucleus
Structure - Ribosomes are made of protein and RNA

7. Endoplasmic Reticulum - eukaryotes
Function - The organelle in which components of the cell membrane are assembled and some proteins are modified
Structure Types
Smooth ER – contains collections of enzymes that perform specialized tasks, such as the synthesis of lipids (fats)
Rough ER – the part that is involved in the synthesis of proteins; has ribosomes embedded in the membrane

8. Golgi Apparatus - eukaryotes
Function -Proteins made by the ER move to the Golgi apparatus where enzymes attach carbohydrates and lipids
Structure – folded sacs involved with modifying and packaging proteins

9. Lysosomes – animal cells
Structure - Are small organelles filled with enzymes
Main function is to break down lipids, carbohydrates and proteins into particles that can be used by the cells
Also helps to break down old organelles, remove debris from the cell

10. Vacuoles – all cells
Function - Storage for the cell
Stores materials such as water, salts, proteins and carbohydrates
Plants have a single large vacuole (mostly water)

11. Chloroplasts – plant cell Found in photosynthetic organisms
Function - Use energy from sunlight to make energy-rich food molecules in a process known as photosynthesis
Structure – Light capturing pigment Contains thylakoids and chlorophyll
Contains its own DNA

12. Mitochondria – eukaryotes
Function - Releases energy from stored food molecules in a process called cellular respiration
Found in eukaryotes
Structure – Small organelle that contains its own DNA (you get it from your momma)

13. Organelle DNA
Lynn Margulis suggested that mitochondria and chloroplasts were originally prokaryotic organisms that were enveloped by a eukaryotic cell
The DNA in mitochondria comes almost exclusively from the mother

14. Movement through the membrane
Facilitated diffusion – no energy required
Molecules such as glucose sugar that cannot cross the cell membrane’s lipid bilayer directly can move through protein channels from an area of high concentration to an area of low concentration with the concentration gradient
Active transport – energy required
When a molecule has to move against the concentration gradient
Each pump is used to move a specific molecule across the membrane
Example: sodium potassium pump moves sodium out and potassium in (

16. The removal of large amounts of material from a cell
Endocytosis
The process of taking materials into the cell by means of infolding or pockets of the cell membrane
Exocytosis
The removal of large amounts of material from a cell
exocytosis

18. ANIMAL AND PLANT