Histo: Plasma Membrane, Cytoskeleton, Nucleus, Connective Tissue Flashcards
List 4 main components of the plasma membrane
phospholipids, proteins, carbohydrates (glycocalyx), cholesterol
The phospholipid bilayer of the plasma membrane has an inner layer called the __ ___ and an outer
layer called ____ _____.
P-face, E-face
Define Amphipathic
molecule with 2 parts: hydrophilic and hydrophobic regions
T/F Membrane fluidity is dependent on cholesterol and temperature
True
List the 6 integral protein categories:
pumps, channels, receptors, linkers, enzymes, structural proteins
Describe Receptor mediated endocytosis in your own words. You must describe how clathrin, adaptor and dynamin proteins work together
Process where ligands bind with surface receptors. Clathrin and adaptor proteins attach to binding sites for ligands. Then dynamin proteins cause constricting loops (invagination) of the bound ligands to form coated vesicles.
What is the function of a ribosome?
to transcribe mRNA; catalyze the formation of peptide bonds, participates in protein synthesis
What is the function of the rough endoplasmic reticulum (Rough ER)?
a membrane bound organelle that ribosomes bind to, during polypeptide synth, participates in protein syth and protein modification
What is the function of the smooth endoplasmic reticulum (Smooth ER)?
a membrane bound organelle, participates in protein syth and protein modification. Can store Ca, glycogen and do steroid hormone synth.
What is the function of the mitochondrion?
a membrane bound organelle that participates in ATP syth and aerobic respiration
What is the function of the the golgi apparatus?
a membrane bound organelle that participates in protein synth and modification. It gives rise vesicles (secretory, lysosomes)
What is the function of the lysosome?
a membrane bound organelle filled with degradative enzymes
What protein are microtubules made out of?
globular protein subunits: a-tubulin and b-tubulin
What is the structure of microtubules?
hollow tube structure - made of dimers (a+b tubulin) 13 dimers in 1 circle
What is the main function of microtubules?
To maintain cell shape.
What structures can microtubules form?
cilium and flagellum
What proteins are microfilaments made of?
Actin filaments (protein)
What is the overall structure of a microfilament? What are the units and subunits called?
a rope like structure; helical, combines two strands. strands are composed individual G-actin ‘beads’; when polymerized in strand known as F-actin
What is the main function of microfilament?
they are the cores of microvilli, also play role in cytokinesis
What specific cellular structures do microfilaments support/ form?
Microvilli
What are the 6 types of intermediate filaments?
Cytokeratin: epithelial origin
Vimentin: mesodermal origin
Desmin: muscle cell origin
Neuro-filament protein: nerve cell origin
Glial fibrillary acidic protein (GFAP): glial cell origin
Lamin: inner side of nuclear membrane
What are inclusion bodies? What types? What are their structural features?
they are accumulated metabolites or other substances ie viral particles, protein aggregates etc.
Types: glycogen, lipid droplets, lipofuscin, melanin
structure: non membrane bound, shape and size vary
What is the structure of cholesterol?
amphipathic: polar hydrophilic head and nonpolar hydrophobic tail
What are the two types of Integral Proteins?
transmembrane and multipass
What do peripheral proteins do?
bind to phospholipids or integral proteins
What is an example of a peripheral protein?
Spectrin
What is spectrin?
peripheral protein that stabilizes the cell membrane of RBC’s
What are the three ways to transport through plasma membrane?
Passive, active and vesicular transport
What is passive transport?
simple diffusion (via channel, pump); no energy required. move down electrochem gradient
What are the types of active transport?
primary and secondary: energy required, goes against electrochem gradient via carrier protein
What is vesicular transport?
endocytosis and exocytosis
What are the types of endocytosis?
phagocytosis, pinocytocis, receptor mediated endocytosis
What is phagocytocis?
engulfiing endocytosis: creates phagosome/vacuole
What is pinocytosis?
drinking endocytosis; forms a pinocytotic vesicle containing liquid
What is exocytosis?
movement of large molecules from inside to outside cell via vesicular transport
What does a cell use to execute exocytosis?
uses secretory vesicles/ secretory granules
What are the 5 types of signal reception?
1) endocrine
2) paracrine
3) synaptic
4) autocrine
5) juxtacrine
What is endocrine signaling?
hormones are carried in blood to target cells in body
what is paracrine signaling?
chemical ligand diffuses in extracellular fluid. rapid metabolism, effect is local
What is synaptic signaling?
neurotransmitters act on adjacent cells via synapses
What is autocrine signaling?
signals bind receptors on the same cell
what is juxtacrine signalling?
cell membrane bound proteins signal when making direct physical contact
What is the shape of a nucleus?
Size and shape vary: spherical, ovoid, elongated, disk, lobulated etc
How many nuclei per cell?
usually 1
multiple: heptocytes
none: erythrocytes
Two main types of nucleus?
Leptochromatic and Pachychromatic
What are leptochromatic nuclei?
Nuclei w/ more open/ available DNA (euchromatin) which is lighter colored
cytoplasm has a lot of rER and Golgi
What are pachychromatic nuclei?
Nuclei w/ more tightly packed DNA (heterochromatin) which is darker colored
cytoplasm has few organelles
What is the nucleus made of and describe each function
Nuclear envelope: two layers of
nuclear membrane
nucleolus: synth of rRNA
Chromatin:
- euchromatin (lighter),
- heterochromatin (darker)
What is the nuclear envelope
Enclosing the nuclear material, and separating it from the cytoplasm
Outer nuclear membrane: It is continuous with the membrane of rER
Inner nuclear membrane
What is the space between two nuclear membranes called and its features
pernicular space: continuation w/ space inside the rER
What are nuclear pores?
openings in the nuclear envelope that permit passage of molecules bidirectionally
What is the nucleolus
Dense structure inside the nucleus
Well developed (prominent) in cells with very active protein synthesis
Nucleolus contains:
- DNA (part of chromosomes): genes that encode for the rRNA formation
- rRNA & protein
What is the function of the nucleolus?
site for the synthesis of the rRNA
What is chromatin?
Consists of double stranded DNA associated with nucleoprotein called HISTONES
Euchromatin:
- Transcriptionally active
- Lightly stained region
- Open/ available DNA
Heterochromatin:
- Transcriptionally inactive
- Location: peripheral, around nucleolus or scattered in nucleoplasm.
- Deeply stained region
- Tightly packed DNA
