BIO120 SSS Sep 2024 Endomembrane Semi-autonomous Cytoskeleton - Answers (PDF)

University Library Structured Study Sessions (SSS): Endomembrane System + Semi- Autonomous Organelles Janelle and Steve Sep 24 2024 Please note: This material has been developed by your awesome Structured Study Sessions...

University Library Structured Study Sessions (SSS): Endomembrane System + Semi- Autonomous Organelles Janelle and Steve Sep 24 2024 Please note: This material has been developed by your awesome Structured Study Sessions Peer Mentor and not your course professors! Selection of session materials is based on your peer mentor’s knowledge and experiences with taking the course and input from the SSS Peer Mentor Team.  University Library Land Acknowledgement As we gather here today, we acknowledge we are on Treaty 6 Territory and the Homeland of the Métis. We pay our respect to the First Nations and Métis ancestors of this place and reaffirm our relationship with one another.  Before We Start… Disclaimer: Remember SSS is supplemental!! We’ll try to cover the high- yield stuff that’s more likely to be tested but we can’t cover everything so please continue to go to lectures! Any questions on previous stuff?? Feel free to raise your hand or check out our Google Forms (completely anonymous)! Either is fine and welcome ☺  Something We’re Incorporating! ▪ Google Forms (will be linked in Canvas in our section) a) Feedback (things you want us to continue, start or stop doing) b) Topics you’re particularly struggling with + would like us to cover c) Questions you would like addressed in the next SSS If you would rather keep your question private, you can email us @ [email protected]  What’s On Today’s Menu? ▪ Endomembrane System (what the heck is it anyways) ▪ Semi-autonomous organelles + examples ▪ Cytoskeleton details ▪ Practice questions and verbal questions along the way! (Don’t worry, I won’t pick on anyone but feel free to participate! Low stakes + judge-free zone here ☺) Part 1: Endomembrane System LEGVVNP!  Okay, so what is it? ▪ Endomembrane system: a network of organelles + structures (membranes) that are involved in the synthesis + transport of proteins and lipids! a) TL;DR – Structures involved in sending/receiving vesicles ▪ Knowing what you know about proteins + lipids and the organelles covered before, what organelles/structures may be part of the EM system??  “LEGVVNP” ▪ L: lysosomes ▪ E: endoplasmic reticulum (rough for proteins, smooth for lipids) ▪ G: Golgi body/complex/apparatus (literally they all mean the same thing) ▪ V: vacuoles ▪ V: vesicles ▪ N: nuclear membrane/envelope (they mean the same thing but this is NOT nucleus or nucleolus) This Photo by Unknown Author is licensed under CC BY ▪ P: plasma membrane  Lysosomes ▪ Membrane-bound vesicles (we’ll discuss vesicles in more detail later) ▪ Responsible for digesting nutrients and/or destroying waste or dysfunctional organelles so the building blocks can be used later a) Think of it as your “recycling bin” ▪ Has enzymes that will fulfill its duties but they only work in low pH (which is why inside of lysosomes has low pH) a) Low pH = acidic b) High pH = alkaline ▪ Only found in animal cells (plant cells have central vacuoles instead) Endoplasmic Reticulum ▪ Covered last week! ▪ Let’s do an active recall recap!!! Rough Smooth Responsible for? Protein folding and/or modifications Lipid (and steroid) synthesis, Ca2+ storage, detoxification Differences in shape Flatter Tubular Differences in surface Has ribosomes (bumpy) No ribosomes (smooth) Endoplasmic Reticulum ▪ Covered last week! ▪ Let’s do an active recall recap!!! This Photo by Unknown Author is licensed under CC BY-SA Rough Smooth Responsible for? Protein folding and/or modifications Lipid (and steroid) synthesis, Ca2+ storage, detoxification Differences in shape Flatter Tubular Differences in surface Has ribosomes (bumpy) No ribosomes (smooth) Golgi Body (because I like that name the most) ▪ Purpose of the Golgi body? a) Final chemical modifications of proteins, tagged to final destinations + sent to correct destination via vesicle, (can manufacture some other molecules like glycolipids) ▪ What “feature” does the structure of a Golgi body have? a) Cisternae! Specifically, flat ones! ▪ What are the two faces called + the difference? a) Cis face (receives proteins + modifications happen), trans face (sends proteins off) ▪ What two other parts of the endomembrane system does it DIRECTLY interact with? a) Vesicles, rough ER Golgi Body (because I like that name the most) This Photo by Unknown Author is licensed under CC BY-SA-NC This Photo by Unknown Author is licensed under CC BY  Vesicles ▪ Little pieces of membrane that usually has fluid in the middle + can transport things within the cell AND to/from the outside of the cell ▪ Two words you should know: a) Endocytosis: brings something INTO something (cell or organelle) Will decrease membrane surface area by taking a piece to create vesicle b) Exocytosis: sends something OUTSIDE of something (cell or organelle) Will increase membrane surface area by giving back to membrane by fusing  Vesicles (Cont.) Exocytosis Endocytosis Image source: https://gifer.com/en/yVe Image source: https://cwoer.ccbcmd.edu/science /microbiology/lecture/unit4/eustruc t/pinocyt.html  Vacuoles ▪ Also membrane-bound areas that have a variety of functions a) Storage of water, pigments, ions, etc. b) Turgor pressure to prevent the cell from bursting or shriveling c) Digest waste d) More specialized functions (pump excess water out, food vacuoles…) ▪ More common in plants and fungi (technically found in animals but to a much lesser degree) a) However, central vacuoles are only found in plants!! Nuclear Membrane ▪ Surrounds the nucleus with a double-layered membrane (outer membrane + inner membrane) ▪ Connected directly to endoplasmic reticulum! This Photo by Unknown Author is licensed under CC BY  Plasma Membrane ▪ Separates the cell from the outside environment ▪ Can be used to make vesicles (endocytosis + exocytosis) ▪ Remember: asymmetrical phospholipid bilayer! This Photo by Unknown Author is licensed under CC BY  Question 1 The ___ sends vesicles from its ___ face and receives vesicles from its ___ face: a) Endoplasmic reticulum; cis; trans b) Endoplasmic reticulum; trans; cis c) Golgi complex; trans; cis d) Golgi complex; cis; trans  Question 1 The ___ sends vesicles from its ___ face and receives vesicles from its ___ face: a) Endoplasmic reticulum; cis; trans b) Endoplasmic reticulum; trans; cis c) Golgi complex; trans; cis d) Golgi complex; cis; trans  Question 2 Which organelle is responsible for the synthesis of lipids and detoxification of drugs? a) Nucleolus b) Ribosomes c) Rough ER d) Smooth ER  Question 2 Which organelle is responsible for the synthesis of lipids and detoxification of drugs? a) Nucleolus b) Ribosomes c) Rough ER d) Smooth ER  Question 3 Endocytosis is movement ____ cell and will ____ the membrane surface area. a) Into; increase b) Into; decrease c) Out of; increase d) Out of; decrease  Question 3 Endocytosis is movement ____ cell and will ____ the membrane surface area. a) Into; increase b) Into; decrease c) Out of; increase d) Out of; decrease Part 2: Semi-Autonomous Organelles Aka the ones that will come back to haunt you at the end of the term  What is “Semi-Autonomous”??? ▪ Have their own (prokaryotic!) DNA which means they can drive some processes by themselves without input from nucleus (replication and protein synthesis - they have ribosomes!) a) Not “fully autonomous” because they depend on the cell for survival! ▪ Not considered part of endomembrane system ▪ Examples: a) Mitochondria b) Chloroplasts c) Plastids Essentially anything that ends in “-plast” like chromoplast, leucoplast, amyloplast, elaioplast… Mitochondria ▪ Site of cellular respiration which is where glucose (sugar) is broken down while using oxygen to make ATP (aka energy) a) Waste products are also created (water + carbon dioxide) ▪ Has double-membrane a) Outer membrane and inner membrane with an “intermembrane space” between it b) Inside of inner membrane is called “matrix” that has lots of cristae (not to be confused with cisternae) This Photo by Unknown Author is licensed under CC BY ▪ Found in plants AND animals!  Chloroplasts ▪ Site of photosynthesis where light, water and carbon dioxide are used to build glucose (sugar) which can be used for energy! a) Waste products are oxygen ▪ Has double membrane AND another membrane on the inside a) Outer and inner membrane separate chloroplast from rest of the cell and hold a liquid called “stroma” b) Inside the inner membrane, there are “thylakoids” with a membrane called thylakoid membrane c) Thylakoids stack to make “grana” ▪ Found in plants This Photo by Unknown Author is licensed under CC BY  If they were both bacteria, who came first? ▪ Remember LUCA (Last Universal Common Ancestors) is an organism that had things ALL modern life forms have and things started branching off the tree of life when they developed unique traits (ex. Eukaryotic cells have membrane-bound organelles while prokaryotes don’t) ▪ Mitochondria are found in animals AND plants which means both can use cellular respiration ▪ Chloroplasts are found in plants only which means animals can’t photosynthesize ▪ Therefore, mitochondria came before chloroplasts.  An Aside: Peroxisomes ▪ NOT ENDOMEMBRANE SYSTEM OR SEMI-AUTONOMOUS but is an organelle nonetheless! ▪ Membrane-bound and has enzymes that will break down fatty acids and detoxify harmful things ▪ Gets its name from its ability to change hydrogen peroxide into water ▪ Important to metabolism ▪ Found in animals and plants!  Question 4 Which of the following organelles are considered semi-autonomous? a) Leucoplasts; Chloroplasts b) Mitochondria; Golgi c) Lysosomes; Mitochondria d) Chloroplasts; Endoplasmic Reticulum  Question 4 Which of the following organelles are considered semi-autonomous? a) Leucoplasts; Chloroplasts b) Mitochondria; Golgi c) Lysosomes; Mitochondria d) Chloroplasts; Endoplasmic Reticulum Note: all plastids are considered semi-autonomous  Question 5 In mitochondria, ___ is broken down to generate ___ while in chloroplasts, ___ is made by using ___ energy. a) Water; ATP; glucose; light b) Glucose; ATP; glucose; light c) Glucose; ATP; carbon dioxide; chemical d) Carbon dioxide; ATP; water; chemical  Question 5 In mitochondria, ___ is broken down to generate ___ while in chloroplasts, ___ is made by using ___ energy. a) Water; ATP; glucose; light b) Glucose; ATP; glucose; light c) Glucose; ATP; carbon dioxide; chemical d) Carbon dioxide; ATP; water; chemical  Question 6 Which of the following statements is false: a) The fluid filled portion of the chloroplast is called the stroma b) Mitochondria came before chloroplasts c) Chloroplasts have 3 membranes d) Chloroplasts are only found in plant cells and mitochondria are only found in animal cells  Question 6 Which of the following statements is false: a) The fluid filled portion of the chloroplast is called the stroma b) Mitochondria came before chloroplasts c) Chloroplasts have 3 membranes d) Chloroplasts are only found in plant cells and mitochondria are only found in animal cells e) Note: Plant cells have both mitochondria and chloroplasts Part 3: Cytoskeleton Skeleton of the cell!  What Is A Cytoskeleton? ▪ System of proteins that come in fibers and tubes to help the cell keep its shape + polarity and go through processes that keep it and the next generation alive! a) Division (mitosis) b) Movement/migration c) Intracellular transport d) Organization ▪ Three types: microtubules, intermediate filaments, microfilaments Microtubule Structure ▪ Made of tubulin dimers (dimer means 2) – 1 alpha tubulin + 1 beta tubulin that have a + end and a – end (is polar) a) + end tends to have more growing and shrinking ▪ 1 microtubule has 13 “protofilaments” which is a chain of tubulin dimers This Photo by Unknown Author is licensed under CC BY-SA  Microtubule Function ▪ Makes up centrosomes + centrioles to make “MTOC (microtubule organizing center)” which helps with mitosis! ▪ Makes up mitotic spindle which This Photo by Unknown Author is licensed under CC BY rips chromosomes apart! ▪ Acts as a road for some motor proteins (kinesin + dyneins) ▪ Makes up motility structures (flagella + cilia) This Photo by Unknown Author is licensed under CC BY-SA-NC  Cilia + Flagella ▪ Both involved in movement + made of microtubules! ▪ Cilia: hair-like structures that “sweep” fluids over cells a) Like a wave/brush This Photo by Unknown Author is licensed under CC BY-NC-ND ▪ Flagella: long appendage that spins and propels cells towards a destination a) Like a whip Microfilament Structure ▪ Made up by double helix (kind of like loose Twizzlers) of actin monomers (mono = 1) ▪ 1 microfilament = 2 “protofilaments” ▪ Has + end and – end which gives POLARITY a) + end does more growing and shrinking This Photo by Unknown Author is licensed under CC BY  Microfilament Function ▪ Holds cell shape and also can change shape ▪ Muscle contraction! a) Interact with myosin (motor This Photo by Unknown Author is licensed under CC BY protein) ▪ Cytoplasmic streaming ▪ Some movement in cell (ex. Pseudopodia in amoeba) ▪ Helps cell division by forming a cleavage furrow! This Photo by Unknown Author is licensed under CC BY  Intermediate Filaments ▪ Made up of a bunch of different intermediate filament protein subunits a) Exact composition (“recipe”) depends on the cell!! ▪ NO polarity ▪ Found inside and outside of cell ▪ Functions a) Holds cell shape b) Holds organelles (including nucleus!) in place c) Forms nuclear lamina (protein layer in inner nuclear membrane holding pores in nucleus in shape) d) Helps form protein found in hair, nails and skin! This Photo by Unknown Author is licensed under CC BY  Question 7 Which of the following has the motor protein correctly paired up with the cytoskeletal element it interacts with? a) Dynein; microtubules b) Myosin; microtubules c) Kinesin; microfilaments d) Dynein; intermediate filaments  Question 7 Which of the following has the motor protein correctly paired up with the cytoskeletal element it interacts with? a) Dynein; microtubules (MTs) b) Myosin; microtubules c) Kinesin; microfilaments (MFs) d) Dynein; intermediate filaments Note: only intermediate filaments do not interact with motor proteins; Kinesin and Dynein interact with MTs, Myosin interact with MFs  Question 8 Which cytoskeletal fiber is correctly matched with the element that it is composed of? a) Tubulin make up intermediate filaments b) Actin make up microtubules c) Tubulin make up microfilaments d) None of the above  Question 8 Which cytoskeletal fiber is correctly matched with the element that it is composed of? a) Tubulin make up intermediate filaments b) Actin make up microtubules c) Tubulin make up microfilaments d) None of the above Note: Tubulin make up microtubules, actin make up microfilaments  Question 9 Of the following groups, which is composed only of structures found within the endomembrane system? a) Vacuoles, plasma membrane, golgi b) Nucleolus, lysosome, nuclear envelope c) Mitochondria, endoplasmic reticulum, lysosome d) Vesicles, Nucleus, Golgi  Question 9 Of the following groups, which is composed only of structures found within the endomembrane system? a) Vacuoles, plasma membrane, golgi b) Nucleolus, lysosome, nuclear envelope c) Mitochondria, endoplasmic reticulum, lysosome d) Vesicles, Nucleus, Golgi Note: N in LEGVVNP stands for “nuclear envelope/membrane”  Question 10 Photosynthesis take place on a structure within chloroplasts that form a stack. These structures (not the stack) are called: a) Stroma b) Cisternae c) Thylakoids d) Grana  Question 10 Photosynthesis take place on a structure within chloroplasts that form a stack. These structures (not the stack) are called: a) Stroma b) Cisternae c) Thylakoids d) Grana Your university library is here to help library.usask.ca