Lecture 3 Flashcards

Question

What is are the 2 types of single raft models?

Answer 1

1. Receptors associated at steady state with lipid rafts could be activated through ligand binding 2. Individual receptors with weak raft affinity could oligomerize on ligand binding, and this would lead to an increased residency time in rafts.

Answer 2

Activated receptors could recruit linking proteins such as cytoskeletal, elements and scaffolds that bind to proteins in other rafts, and this would result in raft coalescence.

Answer 3

1. Clustering of lipid raft can occur extracellularly, within the membrane, and in the cytosol. 2. It can also occur through GPI anchored proteins, either as a primary or co-stimulatory response

Answer 4

The T-cell receptor or TCR is a heterodimer consisting of an alpha and beta chain. the Alpha and beta heterodimer associate with CD3 complex and zeta (ζ) homodimer which contain cytoplasmic ITAM motifs (immune receptor tyrosine-based activation motifs).

Answer 5

1. Lipid raft when the t-cell binds the antigen lead to a confirmation change that 2. causes phosphorylation of the domains of some of the ITAM proteins on the inside of the cell by Src tyrosine kinase which are (activated/phosphorylated through Csk binding to CBP limpid raft protein). 3. Phosphorylated ITAMs act as a membrane docking site for ZAP-70 4. ZAP-70 activate other proteins such as LAT (a raft-associated adaptor) through cross linking 5. LAT can recruit other proteins into the raft and further amplify the signal

Answer 6

for bacteria invasion and gene expression

Answer 7

1. Invagination dependent on protein called clathrin to form a clathrin coated pits - Can intake small molecules 3. Clathrin–dependent endocytosis: Multiple invaginations are creating cave like structures 4. Macropinocytosis: big invaginations that takes up cellular fluid 5. Phagocytosis: the engulfing of microorganisms or other cells and foreign particles by phagocytes

Answer 8

they make the decisions whether to: 1. destroy or recycled in the cell which can be transferred into an endo or lysosomes, 2. or into an acid recycling compartment where it can be transferred into some other part of the cell, 3. or re-routing into some other compartment 4. Some vesicles pinch off the structure and transport it into the surface of the cell

Answer 9

usually refers to the white blood cells that engulf and absorb waste material, harmful microorganisms, or other foreign bodies in the bloodstream and tissues EX: macrophages or monocytes

Answer 10

The main difference between professional and non-professional phagocytes is that professional phagocytes have receptors on their surfaces for detecting harmful objects, such as bacteria, that are not normally found in the body In contrast to professional phagocytes, non-professional phagocytes principle function is not phagocytosis.

Answer 11

lymphocytes, fibroblast, erythrocytes

Answer 12

neutrophils, monocytes, macrophages, sinusoidal, lining cells, langerhan, and mast cells

Answer 13

1. You have a microbe hanging out 2. Complement system of immune system comes and codes bacteria with C3b to recognize and bind to the bacteria, 3. and another molecule called C5a is produces which is a chemoattractant for macrophages. The cells can recognize and bind these receptors, 4. and The cell invaginates into the cell via phagosomes which are fused with lysosomes to form phagolysosomes that degrade and kills the bacteria into little pieces that are exited outside of the cell

Answer 14

Phagocytosis requires actin rearrangements and pseudopod extensions controlled by Rho GTPases

Answer 15

Phagosome formation often requires high amounts of membrane, which is in excess of plasma membrane capacity (mobilization of membranes of different organelles)

Answer 16

In induced – both the bacteria and host cells are active participants in the process Active invasion – host cell is passive and is not doing anything to take the bacteria in, but the bacteria has the activated part and get itself inside of the cell

Answer 17

a. Some bacteria are able to live in a low pH acid/hydrolytic environment of the lysosomes b. Other bacteria evolved ways once inside the vesicle to keep the vesicle at a neutral pH, and therefore no fusion with lysosomes occurs, and therefore they survive c. Some have evolved ways to lyse the vesicles and go into the cytosol before the cell rids of the vesicle

Answer 18

absorptive cells used for taking parts of the lumen M-cells have receptors on the surface that some bacteria can attach to, and internalize inside macrophages to be released, or the macrophages can't destroy them

Answer 19

proteins attached to lipids which can migrate and reside in the lipid raft

Answer 20

Proteins linked to cholesterol