Cell Parts and Functions You have learned about cell parts and functions in the past. In this lesson you will uncover new details about the main organelles, but more importantly you will use your background in biochemistry to better understand what each organelle is made of and how their composition relates to their functions. This note will closely follow the content of section 2.1 of your textbook. Refresh your memory about the cell parts by labeling and colouring the diagram below. (Pg. 72) Summary of Protein Production: DNA RNA Ribosomes ER Golgi Holds the complete set of instructions to make all proteins in an organism Contained within the nucleus Copy of a gene (instructions to make one protein) Can leave the nucleus and travel to cytoplasm These are protein producing enzymes They read RNA and use it’s code to assemble amino acids in the correct order to build proteins Ribosomes covering its surface make proteins into this system of tubes Inside, proteins can be modified or moved through the cell Vesicles from the ER may go to the Golgi Here proteins get final modifications, are sorted, packed into vesicles and shipped to their final location. Other Cell Parts: Mitochondria Vesicles, vacuoles, lysosomes Centriole (in animal cells only) Process carbohydrates to produce cellular energy (ATP) Bubbles of membrane Vesicles for transport Vacuoles for storage Lysosomes hold digestive enzymes Create spindle fibres used to separate chromosomes during cell division
Transcript
Cell Parts and Functions
You have learned about cell parts and functions in the past. In this lesson you will uncover new details about the main organelles, but more importantly you will use your background in biochemistry to better understand what each organelle is made of and how their composition relates to their functions. This note will closely follow the content of section 2.1 of your textbook. Refresh your memory about the cell parts by labeling and colouring the diagram below. (Pg. 72)
Summary of Protein Production:
DNA RNA Ribosomes ER Golgi Holds the
complete set of instructions to make all proteins in an organism
Contained within the nucleus
Copy of a gene (instructions to make one protein)
Can leave the nucleus and travel to cytoplasm
These are protein producing enzymes
They read RNA and use it’s code to assemble amino acids in the correct order to build proteins
Ribosomes covering its surface make proteins into this system of tubes
Inside, proteins can be modified or moved through the cell
Vesicles from the ER may go to the Golgi
Here proteins get final modifications, are sorted, packed into vesicles and shipped to their final location.
Other Cell Parts: Mitochondria Vesicles, vacuoles, lysosomes Centriole (in animal cells only) Process carbohydrates to produce
cellular energy (ATP) Bubbles of membrane
Vesicles for transport
Vacuoles for storage
Lysosomes hold digestive enzymes
Create spindle fibres used to separate chromosomes during cell division
Plant Cells: If the cell on the previous page were a plant cell, there would be four key differences
no centrioles
cell wall
large water vacuole
chloroplast
Instead, plant cells use a microtubule organizing center (MTOC) that only appears during cell division.
Each plant cell is coated in a tough rigid cell wall outside its cell membrane that is mostly composed of cellulose
To maintain plant structure, cells are filled with a large water filled vacuole. Filling it applies pressure to the cell wall to keep it rigid. This is called turgor pressure.
This organelle is the site where photosynthesis takes place.
Organelles and the Macromolecules Remember that cell parts are made primarily from the 4 macromolecules. Below is a summary of the main roles of each macromolecule as they apply to cell parts:
Lipids Proteins Nucleic Acids Carbohydrates
- All membrane bound organelles are composed structurally of phospholipids.
in each membrane of each organelle to give them their unique jobs
- Enzymes are dissolved in the fluids within membrane bound organelles to orchestrate chemical reactions
- Fibrous proteins (microtubules, intermediate filaments and microfilaments) form:
- The cytoskeleton (a scaffold to help cells hold their shape)
- cilia and flagella - spindle fibres
- There is DNA stored in
the nucleus, mitochondria, and chloroplasts
- The nucleolus has no membrane, but is rather a region of the nucleus that is rich in protein and nucleic acids. This region is where ribosomes and other RNA based structures are manufactured.
- While their main role is
to provide energy for cells, in plants, they form the cell wall (cellulose)
Nuclear Envelope (aka Nuclear Membrane)
Double membrane bound organelle
Outer membrane is continuous with the rough ER to provide a tight interface between RNA and ribosomes for protein production
Complex nuclear pore proteins regulate what goes in and out of the nucleus.
Inner membrane contains proteins which anchor chromosomes in specific arrangements to organize them and control gene expression.
Diagram of a single nuclear pore
Electron micrograph of several nuclear pores.
The Endomembrane System
To make proteins, enzymes, and lipids several membrane bound organelles work together
Vesicles can break off from one organelle and merge (with their contents) with another organelle.
Proteins are made by ribosomes directly into the ER where enzymes are waiting to modify them into functional forms.
Vesicles from the ER with these newly formed protein may go to the smooth ER where they will be used as enzymes to manufacture new lipids or go to the Golgi for further modifications
The Golgi will send out vesicles of finalized proteins that have two possible fates:
Become part of other organelles like lysosomes or peroxisomes
Merge with the cell membrane to add lipids and/or proteins to it or to export contents outside the cell
Vesicles
Bubbles budded off from organelles or the cell membrane (categorized based on their contents and/or functions)
o Transporting materials from one organelle to another as described in the endomembrane system o Bubbles containing enzymes
Lysosomes contain digestive enzymes Peroxisomes contain enzymes for varied metabolic reactions including breakdown of H2O2
o Bubbles containing food, water and wastes (vacuoles) o Vesicles can fuse to mix their contents
A vacuole can fuse with a lysosome to digest the contents of the vacuole
Mitochondria and Chloroplasts
Mitochondria and chloroplasts are double membraned organelles.
Between their membranes they create a concentration gradient of H+ ions. o Allow H+ ions to flow along their gradient through the enzyme ATP synthase to generate ATP.
Mitochondria use glucose to generate the gradient and release their ATP for use in the cell. Chloroplasts use energy from the sun to generate the gradient and use the resulting ATP to make
glucose (used to build cell walls or used later to regenerate ATP in the mitochondria).
Mitochondria Chloroplast
Microtubules, Microfilaments, and Intermediate Filaments
These are fibrous proteins that can quickly self-assemble and breakdown from protein subunits
They are important construction materials in cells used for a wide variety of functions o Cytoskeleton, centrioles / spindle fibres, contractile fibres for muscles, cilia and flagella.
Microtubules Microfilaments
Intermediate Filaments
These three fibrous proteins work together to give the cell structure, allow movement of organelles through cells and allow for locomotion.
Take your own summary notes below about cilia, flagella, pseudopods
The Cell Surface Distinguish between the primary and secondary cell well:
