click below
click below
Normal Size Small Size show me how
Chapters 8 & 9
Mitochondria, Chloroplasts and Peroxisomes
Question | Answer |
---|---|
List the functions of Mitochondria | • Form an interconnected network • Continual fusion and fission • Power plant of cell • Plays role in cell survival |
True or false: Mitochondria, chloroplast contain own genome, peroxisome does not | True |
What is extreme wobble? | U in 3rd position of anticodon can pair with any base (GATC) |
matrix | citric acid cycle, etc. Mitochondrial genome |
inner membrane | cristae where oxidative phosphorylation occurs impermeable to ions and proteins ETC, ATP synthase & transporters |
outer membrane | porins anything less than 6000 daltons , ions and other small particles can freely pass into the intermembrane space |
intermembrane space | enzymes that use ATP |
Mitochondria genetic code is different the general genetic code | some codes different aa |
What happens to proteins encoded by cellular genome? | move from cytosol to mitochondria |
Mitochondrial DNA is similar to -proteobacteria | probably evolved from symbiotic bacteria |
Metabolism Stage 1 | digestive enzymes break down macromolecules |
Metabolism Stage 2 Part 1 | Glycolysis breakdown of individual glucose molecules into 2 pyruvate |
1 Glucose molecule | 2 molecules of pyruvate 2 molecules of ATP 2 molecules NADH |
Metabolism Stage 2 Part 2 | Pyruvate converted to acetyl CoA in mitochondria matrix |
Metabolism Stage 3 Part 1 | Citric acid cycle (in matrix) oxidizes & converts acetylCoA to 3 NADH 1 FADH2 1 GTP 2 CO2 |
if mom has mutation in mitochondria | all offspring will carry it |
Leber’s hereditary optic neuropathy | mitochondrial mutation |
mitochondria and chloroplast proteins | synthesized on free ribosomes in the cytosol and then transported to mitochondria and chloroplast |
Mitochondria coded inner membrane proteins | translocated to inner membrane through Oxa translocase |
Mitochondria proteins (not folded) | translocated from cytosol through TOM and TIM translocator |
mitochondria phospholipids | synthesized in ER and imported to mitochondria by Phospholipid transfer proteins |
1 Pyruvate molecule | Acetyl CoA CO2 NADH |
Metabolism Stage 3 Part 2 | Electron transport drives the synthesis of ATP |
Electron transport & Oxidative phosphorylation | transfer their electrons through a chain of acceptor and donor molecules in inner membrane. Each time the electrons are passed, they fall to lower energy states and the energy released is used to make ATP. ATP synthase is a motor protein |
Oxidative Phosphorylation | ATP synthase couples P onto ADP |
Mitochondria vs. chloroplasts | Both have circular DNA Both have a porous outer membrane Both have inner membranes but choloroplasts have 2 inside |
Mitochondria vs. chloroplasts similar structures | Inside thylakoid disks = intermembrane space of mitochondria note ion concentration stroma = matrix where enzymes in Calvin cycle and DNA are located thylakoid membrane most like inner membrane of mitochondria - electron transport |
Chromoplast | Colored plastids that contain various pigments and synthesize food materials by photosynthesis. They contain yellow, orange and or red pigments |
red | rhodoplast. It contains phycoerythrin. It is found in red algae. |
dark brown | Phaeoplast. It contains fucoxanthin pigments. It is found in brown algae, diatoms and dinoflagelates. |
green | Chloroplast. It is in green color. It contains chlorophyll pigments. It is found in higher plants and green algae. |
Leucoplasts | They are non-pigmented plastids (Their main function is to store food materials and do not involve in synthetic activities.) Amyloplast, Elaioplast, Proteinoplast |
Amyloplast | It stores starch and found in tubers, cotyledons and endosperm |
Elaioplast | it stores oil and found in the epidermal cells |
Proteinoplast | It stores protein and found in seeds and nuts. |
Proplastids | small undifferentiated organelles |
Plastids | chloroplast -> proplastids -> plastids Mature plastids can switch 1. chromplasts from chlorplasts in tomatoes 2. thylkoids break down, carotinoids synthesized, orange color |
Function of Chloroplasts | Fix CO2 in the air into carbohydrates by photosynthesis Generate energy Synthesize amino acids, fatty acids and the lipids for their own compartments Reduction of nitrite (NO2) to ammonia (NH3) Getting Nitrogen into organic molecules |
structure of chloroplasts | 5-10 micron long double membrane = chloroplast envelope 3rd membrane = thylakoid membrane 3 compartments, intermembrane space, stroma, thylakoid lumen Outer membrane porous Inner membrane impermeable to ions & metabolites |
N terminal signal sequence | proteins made in cytosol and imported to inner membrane matrix TOM (outer) to TIM23 (inner) |
internal signal sequence | proteins imported into mitochondrial inner membrane chaperons bind TIM 9-10 and translocate through TIM22 |
Proteins are transported to chloroplasts outer and inner membranes through | Tic and Toc |
Sec pathway | recognize thylakoid signal seq, target protein to Sec translocon using energy from ATP hydrolysis |
TAT pathway | signal seq contains two arginine targets folded protein to TAT translocon using energy from proton gradient |
SRP pathway | signal seq recognized by SRP (signal recognition particle) and pass through Abl3 translocase |
light cycles occurs in | thylakoid membrane |
calvin cycle (dark cycle) occurs in | stroma |
Peroxisome Structure | Small single membrane bound organelles Contain enzymes that carry out metabolic reactions, including energy metabolism NO DNA All protein and encoded by nuclear genome and synthesized on free ribosomes then imported When get big enough they divide |
Functions of Peroxisome | Oxidize certain organic molecules and degrade the hydrogen peroxide (H2O2) produced by these reactions. Glyoxylate cycle to convert stored fatty acids to carbohydrates |
photorespiration | to metabolize a side product, 2 carbon sugar, formed during photosynthesis to glycine |
Zellweger spectrum disorder | Dysfunctional peroxisome |