Cell Biology: Protein Transport Mechanisms

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Questions and Answers

Kedise mmọ mkpụrụngwa ọzọ a ma apụtara n'osisi yi?

Hidrolasa

Manosa 6P (correct)

Clatrina

Golgi

Kedu ihe bụ ọrụ nke AP1 na usoro a?

Na-arụ ọrụ dị ka ịkpọrọ (correct)

Na-ejikọta clatrina

Na-emepụta mkpụrụ oligosaccharides

Na-achịkọta hidrolasas

Kedu ụzọ nke secreción na-apụta na cell niile?

Secreción citoplasmática

Secreción constitutiva (correct)

Secreción golgi

Secreción kích hoạt

Kedu ọrụ ndị receptor MP6 na membrana Golgi?

Na-anabata mkpụrụ MP6 Signup and view all the answers

Kedu ebe hidrolasa na-aṅụrịrị ogologo ọrụ?

Na netwọk CIS Signup and view all the answers

Ké emi inya uriọk uyo n'ibene enye?

Proteínas SNARE Signup and view all the answers

Ké ukara ke inyen enye n'ibed ndokpo?

GDP Signup and view all the answers

Ké mkpọ ikong ke proteínas Rab?

Mkpokre nke protein Signup and view all the answers

Ké ini nyin ke proteins SNARE?

Ikpọkpọ vesículas Signup and view all the answers

Ké ini ami proteins Rab?

Ikpọkpọ vesículas Signup and view all the answers

Ké ini na adia esing ke proteins Rab n'ibed?

Awe kpa Signup and view all the answers

Ukpọrọb lipídic membrane kè smit proteins SNARE?

N'ibed Signup and view all the answers

Ké mkpọ ikong proteins GEF?

Ikpọkpọ GTP Signup and view all the answers

Kediek nyin esie odudu ubong mbakara ikang yene?

RE ye mmo adehe ndi agba Signup and view all the answers

Ibom enye onyo edim-re enyi?

Ikang protein no mbakara Signup and view all the answers

Kediek mmo ye ajọ ikang protein na Golgi?

Nde nyin de ude okon Signup and view all the answers

Kediek ibom mmo re protein esiere ezali na vesículas?

Ikang protein eyiong Signup and view all the answers

Nyin kiet esit ikang protein na ribosomas?

Nde mmo ebot Signup and view all the answers

Kediek ibom kiet protein mikọrọ mmo?

Cisterna imọn Signup and view all the answers

Kediek ikang protein esie ubong ikang umọn?

Ribosomas free Signup and view all the answers

Kediek sīre yömechanism makpọ nset mmo?

RE → Golgi → vesículas → membrane pérk Signup and view all the answers

Kpọmkọm, gịnị mere transportadores lisosoma ji eme ihe?

Ha na-ebufe nri na cytosol. Signup and view all the answers

Nke a bụ eziokwu banyere ATPasa nke H+ na lisosoma?

Ọ na-enyere aka igbu H+ site na ATP. Signup and view all the answers

Gịnị bụ isi nke isi mmalite dị iche iche nke lisosoma?

Fagocytosis, autofagia, na usoro konju. Signup and view all the answers

Nke a adịghị enye ngosipụta nke lisosoma?

Ha bụ nnukwu na ndabere. Signup and view all the answers

Kedu usoro nke efu na-eme ka edebe efu?

Nucleation, closure, fusion, na degradation. Signup and view all the answers

Kedu ihe dị na bodies residual?

Ha nwere àgwà lipids na-colored brown. Signup and view all the answers

Nke a bụ eziokwu banyere macrophages na neutrophils?

Ha na-ejide na diger ọtụtụ ihe. Signup and view all the answers

Kedu ihe bụ jiri akụkụ ahụ na-arụ ọrụ nke lisosoma?

Ikike agha. Signup and view all the answers

Ké akpọrọ usoro nke ngwanrọ peroxisoma?

Eserese spherical Signup and view all the answers

Ké nwa ngwanrọ nwere olileanya nwere DNA na ribosomes?

Mitochondrias Signup and view all the answers

Ké enzyme nke anọchiteme n'ime peroxisoma?

Catalase Signup and view all the answers

Ké ụdị protein na akpọrọ peroxins?

Pex 1, Pex 2 Signup and view all the answers

Ké ebe ndị peroxisomas dị elu n'ahụ mmadụ?

N'obi Signup and view all the answers

Ké ụzọ na-abanye protein n'ime peroxisoma?

Site na RE Signup and view all the answers

Ké ọtụtụ genes nke coding protein peroxisoma anọpụtara na genom humano?

Ndi 85 Signup and view all the answers

Ké ụzọ peroxisomas na-ekekọta protein?

Importación selectiva Signup and view all the answers

Kéde ndien esie keme isong isong ke membrana mitocondrial?

Emi mmo enyene isong ke lipids ke 60%. Signup and view all the answers

Kéde ikó isong ke mmen ena yene mitocondrial?

Enye ka efen nkut ke 40%, 60% ke proteini. Signup and view all the answers

Kéde asana efen isong ke citosol?

Eyi mmo ewutak ke proceso de detox. Signup and view all the answers

Kéde ndien esie asana asana efen mmen ena yene ribosomas?

Kéde isong 55-60S. Signup and view all the answers

Kéde ndien isong ke porinas?

Ndị protein na ebé anie aquosos. Signup and view all the answers

Kéde ikó asana etok isong ke mmen mitocondrial?

Kéde imesin na istong ke matrix. Signup and view all the answers

Kéde asana iké mmen allmɛn ke mitochondria?

Kéde rigidity. Signup and view all the answers

Kéde asana asana iké citosol ke autophagosomos?

Ndi isi non selective. Signup and view all the answers

Study Notes

2º Partial Cellular Biology

This is a study document for a second partial exam on cellular biology.
The document was created by Paula Ferrández López.
The course is 1st year of Medicine at the UCAM University with Sonia Sánchez as Professor.

Topic 11: Endoplasmic Reticulum

The Endoplasmic Reticulum (ER) is a crucial crossroads for protein traffic in eukaryotic cells.
The ER is involved in protein processing and distribution.
Proteins synthesized by ribosomes bound to the ER membrane are generally destined for secretion, the ER, Golgi, lysosomes, or the plasma membrane.
Proteins destined for the cytosol, nucleus, mitochondria, chloroplasts, or peroxisomes are synthesized by free ribosomes and released into the cytosol.
The ER is a continuous membrane network extending from the nuclear membrane throughout the cytoplasm, forming a network of tubules and sacs/cisternas. It's the largest organelle in most eukaryotic cells.
There are two main types of ER: Rough ER (RER) and Smooth ER (SER).
RER has ribosomes on its surface and plays a role in protein processing.
SER lacks ribosomes and is involved in lipid metabolism.

Topic 2: RER

RER membrane is thinner than the plasma membrane (70% proteins and 30% lipids).
It has two sides: a side facing the cytosol (with ribosomes) and a lumenal/light side (without ribosomes).
RER stores proteins made by ribosomes, preparing them for glycolysation and packaging before being sent to other organelles or outside the cell.

Topic 3: RER protein synthesis pathways

Co-translational: Proteins are translocated into the ER while they are still being synthesized by ribosomes. This is the most common pathway in mammals.
Post-translational: Proteins are translocated into the ER after their complete synthesis, this pathway can be used in yeast.
Signal peptides: These peptides direct proteins to the ER membrane. They are typically hydrophobic amino acids followed by a few basic amino acids; located at the N-terminal.

Topic 4: Protein translocation into the ER lumen

Signal Recognition Particle (SRP): Binds to the signal peptide and the ribosome.
SRP receptor: on the ER membrane, binds to the SRP and slows down translation temporarily.
Translocation channel/Translocon: Protein-conducting channel in the ER membrane that guides the growing polypeptide chain into the ER lumen.
Signal peptidase: cleaves the signal peptide once it's inside the ER.

Topic 5: Synthesis pathway

RER → Golgi → Secretory vesicles → outside the cell pathway.
RER → Golgi → plasma membrane, lysosome, and other destinations. Other times proteins stop at the RER or Golgi for further action.
Proteins destined for other destinations than RER, Golgi, lysosomes, or plasma membrane are made on freestanding ribosomes. These proteins remain in the cytosol once translation is completed.
Integral membrane proteins use a signal-anchor sequence that directs them into the ER membrane. Multi-pass transmembrane proteins need multiple start and stop signals.

Topic 6: Protein synthesis in the RER:

Ribosomes synthesize proteins destined for secretion (e.g., plasma membrane) attach to the ER. This procedure enables the production of soluble proteins and integral membrane proteins.
These proteins enter the ER, either during or subsequent to translation.
Signal peptides on newly synthesized proteins direct them to the ER.
SRP recognizes and transports the ribosome-RNA complex towards the ER membrane.

Topic 7: Synthesis of transmembrane proteins

Proteins destined for the ER, Golgi, lysosomes, or plasma membrane are initially directed to the ER.
Proteins that will remain in the cytosol or go to the nucleus, mitochondria, or other organelles will be synthesized on free ribosomes.
Proteins will enter the ER during translation
Proteins with signal peptide get targeted into the ER
Proteins that will enter the ER need a signal peptide

Topic 8: SER Characteristics

The SER is devoid of ribosomes
It plays role in lipid metabolism: synthesis of lipids used for membrane development and hormone synthesis

Topic 9: Golgi Structure/Composition

The Golgi is composed of flattened, stacked, and membrane-enclosed sacs called cisternae.
Multiple cisternae, grouped into stacks of 4-6 form a dictyosome.
The Golgi has a distinct cis and trans face.
The cis face receives material from the ER, and the trans face buds off vesicles for the next destination.
A network of tubules and cisternae are associated with cis and trans faces, as well as medial compartments.

Topic 10: Golgi Functions

The Golgi apparatus processes, modifies, and sorts proteins/lipids from the ER.
Material arriving from RER proceeds gradually through the cisternae.
The Golgi modifies proteins or lipids and decides what will happen to them: membrane of plasma, being secreted, or being sent to lysosomes.
The Golgi modifies N-linked oligosaccharides synthesized in the ER.

Topic 11: Lysosomes: Introduction

Lysosomes are membrane-bound organelles that contain hydrolytic enzymes. The enzymes can digest various biological polymers (proteins, nucleic acids, carbohydrates, and lipids).
Lysosomes are important for cellular waste disposal.
Lysosomes contain acid hydrolases.

Topic 12: Acid hydrolases

Lysosomes contain around 50 different types of acid hydrolases.
These enzymes need an acidic environment (around pH 5) for optimal activity, and these are protected from the neutral pH of the cytosol by the lysosomal membrane
The pH in lysosomes is maintained by an ATP-driven hydrogen pump in the membrane that imports H+ into the lysosome.
Damage to the lysosomal membrane would lead to release of its acid hydrolases which could digest the cell.

Topic 13: Endocytosis and Lysosome Formation

Lysosome formation involves a combination of secretory and endocytic pathways.
Material is ingested into endocytic vesicles, then combines with early endosomes, matures into late endosomes, and finally fuses with preexisting or developing lysosomes.
The pH in lysosomes is maintained by active proton pumps in the membrane.
Cellular components/materials delivered via endocytosis.

Topic 14: Mitochondria: Structure and Function

Mitochondria are double membrane-bound organelles with a characteristic inner membrane arranged into cristae. The outer membrane is relatively smooth, whereas the inner membrane has folds called cristae, increasing its surface area.
The outer and inner membranes enclose distinct compartments: an intermembrane space and the mitochondrial matrix.
The matrix contains ribosomes, DNA, and enzymes crucial for cellular respiration.
The major function of the mitochondrion is ATP production using cellular respiration (oxidative phosphorylation)

Topic 15: Mitochondria: Composition of the Membranes

The outer membrane of mitochondria possesses a high proportion of porins.
The inner membrane of mitochondria has a high protein content.

Topic 16: Nucleus: General Characteristics and Functions

The nucleus is a double membrane-bound organelle that contains the cell's genetic material (DNA).
It's the control center of the cell, regulating its activities.
It houses the genome (the complete genetic information of an organism).

Topic 17: Nuclear Organization/Composition

The nucleus contains chromatin, consisting of DNA and proteins (histones).
In nondiving cells, chromatin exists as a dispersed/extended material known as euchromatin.
During cell division, chromatin condenses significantly to form chromosomes.

Topic 18: Cell Cycle

The cell cycle is the series of events that takes place in a cell leading to its division and duplication.
Interphase includes G1, S, and G2 phases, where the cell grows, replicates its DNA, and prepares for division.
Mitosis is the process where the duplicated genetic material is divided into two identical daughter cells.
There are different checkpoints in the cell cycle to regulate progression and ensure accurate duplication.

Topic 19: Mitosis - Stages

Mitosis has distinct stages (prophase, prometaphase, metaphase, anaphase, telophase, and cytokinesis).

Topic 20: Meiosis - Introduction/Stages

Meiosis is a specialized type of cell division that produces haploid gametes (sperm and eggs) for sexual reproduction.
Meiosis I is a reductional division, and meiosis II is an equational division.
Meiosis involves crossing over during Prophase I
Meiosis involves several steps (prophase, metaphase, anaphase, and telophase) in both meiotic divisions that lead to 4 haploid cells.

Topic 21: Peroxisomes - Introduction

Peroxisomes are single membrane-bound organelles.
They contain enzymes that use oxygen to oxidize various substrates.
Cellular respiration leads to ATP formation and is regulated by various checkpoints. Peroxisomes are particularly important for certain lipid metabolism processes.

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Nke a bụ ihe nkuzi gbasara atụmatụ na ọrụ nke proteins na sel. Quiz a ga-enyere gị ka ịmara nyocha mkpọrọb na membrane, ọrụ receptor, na ụzọ nyefee proteins. Nwetaghachi ihe ọmụma gị gbasara usoro mmepụta na ngwanrọ nke proteins.