Cell Organelles and Function

Objectives

describe the structure and function of cell organelles

compare and contrast structures of plant and animal cells

Recallmicroscopes provide the ability to study cells

allowed biologists to increase their understanding of the structure and function of cells and cell organelles

RecallThere are two types of cells

prokaryotic and eukaryotic - these differ in size and complexity

Organelle

a specialized structure within a cell with a specific function

examples: nucleus, chloroplast

organelles are the functioning parts of the cell, they work together to allow the cell to perform life processes

some organelles are enclosed in their own membrane - others are not

https://www.youtube.com/watch?v=Fzj6TRnXmps&feature=related

The Nucleusthe mayor of city hall

the nucleus houses the majority of genetic material of a cell

the “brain” of the cell

controls all activity within the cell

uses DNA as a blueprint (similar to a city or building) to direct the production of protein

The Nucleuscontains a eukaryotic cell’s genetic library

The Nucleusnucleolus - the densest area within the nucleus; the location for production of ribosomes

chromatin - stringy material made of proteins and DNA that makes up the majority of the nucleus

chromatin is composed of DNA and protein, just before the cell divides it condenses into chromosomes

note: chromosomes float inside of the nucleus around the nucleolus, they are not found in the nucleolus

Chromosomes

hereditary material within the nucleus

made up of coiled DNA and proteins

carry the genetic code

each species has a characteristic number of chromosomes - humans have 46

Ribosomescarry out manual labour in the form of protein synthesis for the nucleus (factories)

bring together all the raw ingredients such as RNA (copies of the original DNA blueprints) and amino acids to assemble proteins

the proteins created are essential to cell and organismal function

they can be attached to the ER or free-floating in the cytoplasm

Ribosomes and Protein

think of proteins as machinery for cell function, similar to electricity and plumbing in a real city

the nucleolus is a non-membrane bound structure in the nucleus

it is composed of proteins and nucleic acids found within the nucleus

these proteins (rRNA) form future ribosomes

The Endoplasmic Reticulum

two types of ER - smooth ER and rough ER

this extensive network makes up approximately half of all membranous tissue of the cell and is the site of membrane and protein synthesis

the ER system is much like a road system along which industry can be found - twisting network of canals and sacs that connects the cell membrane to the nuclear membrane

goods are manufactured and shipped to needed areas via the ER “road systems”

Rough ER is named for the presence of ribosomes along its membrane and is the source of protein

Smooth ER lacks ribosomes and is responsible for lipid synthesis and processes a variety of metabolic principles such as drug detoxification

The Endoplasmic Reticulum

Golgi Apparatusalso known as the golgi body or the golgi complex

processes and packages macromolecules such as proteins and lipids

particularly important in the processing of proteins for secretion

forms a part of the cellular endomembrane system

the golgi body produces vesicles

The Endomembrane System

the ER manufactures membranes and performs many other biosynthetic functions

the golgi apparatus finishes, sorts, and ships cell products

Lysosomesdigestive sacs that can break down macromolecules in the cell and various structures as needed

digestion is carried out with lysosomal enzymes

similar to waste disposal in cities, lysosomes keep excessive or bulky macromolecules from building up in the cell

found only in animal cells

http://highered.mheducation.com/sites/0072943696/student_view0/chapter3/animation__lysosomes.html

Vesiclesmembrane packages composed of a lipid bilayer

four main types of vesicles:

vacuoles

lysosomes

transport vesicles

secretory vesicles

Vacuolesmembrane bound sacs or spaces containing water or other materials

food vacuoles are digestive organelles they become waste vacuoles once digested

contractile vacuoles maintain water balance - plant cells

plant cells have a central vacuole that is important in maintaining plant turgidity

Plants vs. Animal Cells

mitochondria in red

nucleus in peach ER in blue

mitochondria in red

nucleus in green plastids in yellow

Plant vs Animal Cells

we can identify three organelles unique to plant cells:

cell wall (versus the cell membrane in animal cells)

central vacuole (regular vacuoles are found in animal cells

chloroplasts (animals do not perform photosynthesis - this is what makes plants autotrophs and animals heterotrophs)

https://www.youtube.com/watch?v=uohe2V4yOzE&feature=BFa&list=PLC29EC4BD3F282504

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Plant Cell 1. nuclear pore 2. chromatin 3. nucleolus 4. nuclear membrane 5. ribosomes 6. ER 7. vesicles 8. cell membrane 9. & 12. cell wall 10. cytoplasm 11. golgi body 13. mitochondria 14. & 15. microtubule 16. chloroplast 17. vacuole

Energy Transduction Organelles

mitochondria and chloroplasts are the main energy transformers of the cell

Energy Transduction Organelles

mitochondria carry out the processes of cellular respiration

they make chemical energy for the cell known as ATP from oxygen

chloroplasts carry out the processes of photosynthesis (process of converting light into chemical energy)

pigment (chlorophyll)

Cytoskeletonprovides structural support to the cell, the cytoskeleton also functions in cell mobility and regulation

microtubules - compression support

microfilaments - tension support

centrosomes and centrioles

used in animal cell division

cilia (microvilli) and flagella in prokaryotes

Cell Surface and Junctions

plant cells are encased by cell walls

they also have a cell membrane beneath the cell wall

membranes are a characteristic of all cells

Cell Membrane (Plasma)

animal cells have these

separates the interior of all cells from the outside environment

serves as protection and keeps cell contents together

selectively permeable - controls what comes in and out

made up of fats, lipids, and proteins

https://www.youtube.com/watch?v=qBCVVszQQNs

phospholipid - composted of a phosphate and

fatty acid

hydrophilic head is “water loving” or soluble in water

and the hydrophobic tail is “water hating” or insoluble in water

Cell Membraneproteins float around within the membrane or on its surface

functions:

structural support

surface binding sites for molecules like hormones

recognition sites for cell to cell communication and interaction

transport molecules across the membrane

also contains cholesterol - keeps phospholipids stable and helps retain the membranes shape

Additional Resources

•Cell Grand Tour: www.youtube.com/watch?v=8IlzKri08kk

•Tour of the Cellhttp://www.youtube.com/watch?v=1Z9pqST72is

• Bio-Coach activity: Self-quiz with answers http://www.phschool.com/science/biology_place/biocoach/cells/quiz.html?x=150&y=15

• Biology: Cell structureshttps://www.youtube.com/watch?v=URUJD5NEXC8