Physiology L1R Flashcards
where are protoplasm and cytoplasm located in the cell?
Tissue:group of cells organized to perform one or more specific funtions.
Histology: the study of Microscopic structure of normal tissue
Hispothology: Microscopic structure of diseased tissue
Protoplasm : Living component of the cells,subdivided
- Cytoplasm
- Nucleus
- Inclusions: Non living material ( crystals and pigments)
Cytoplasm: cell located outside the nucleous. contains
- Organelles
- Inclusions
In a cytoplasmic matrix. ( inorganic ions and organic molecules)
list the (non) and Membranous Organelles and the
Organelles described as:
- Membranous Organelles
- the plasma (cell) membrane
- R. endoplasmic reticulum surface
- S.endoplasmic reticulum
- golgi appartus
- endosomes,lysosomes
- transport vesicles - Non-Membranous Organelles
- microtubles
- filaments
- centrioles
- ribosomes
Nucleus: membrane bound compartment that contains, genetic info., with machinary for DNA replication ,& RNA Transcription and processing
non dividing cell ( nucleus):
-Chromatin,nucleolus,Nuclear envelope,Nucleoplasm
Nucleus enclosed by Nuclear envelope:
- Inner Nuclear envelope:
- Perinuclear cistern
- Outer nuclear membrane: sttuded with ribosomes and @ some places its is continuer with rER.
*inner and outer mem. fuse at some places and form nuclear pores communicate with cytoplasm.
*nuclar pores gaurded by protien assemblies = Nuclear pore complexes ( like club bouncers)
Chromatin: form of DNA when cell is in Interphase. Chromosomes uncoiled and chromatin have 2 states;
- Euchromatin
- Heterochromatin
Nucleolus : mommembrane boudn spherical struture involved in transcription of genes coding for ribosomal RNA .
What proteins are found in the plasma membrane and their functions?
Plasma Membrane is a barrier between the cell. contains cholestorol and
Phospholipid bilayer:
- Integral protiens
- peripheral portiens
1. some substances like fat soluble and small uncharged molecules cross membrane through simple diffusion. All other need ……
membrane transport proteins: 2 types
1.Carrier Protiens: tansfer small water soluble molecules.
- some carriers Pro. are very selective ( uniport)
- others do couple transport, this couple can travel in the same direction (symport) or opposite directon (antiport).
*Pro. Carriers such as Na+/K+ pump or H+ pump require energy for active transport.
-
Channel protiens:Ions and other small charged molecules transported through the plasma membrane by Ion-selective channel protiens.
- In neurons: voltage -gated ion channels
- Skeletal muscle: ligand gated ion channels
difference between Endocytosis and Exocytosis?
Endocytosis has 3 process
1.pinocytosis: random ingestion of fluid and small protein by small vesicles.
2.phagocytosis: uptake of particulate matter.
3. Receptor-mediated endocytosis: Low-density Lipoprotiens
Exocytosis: inside to out of cell 2 pathways
- Constitutive secretion: substances are sent in transport vesicles to Plasma Mem.
- Regulated Secretion: special cells ( endocrine, exocrine, neurons ) store them in vesicles in the cytoplasm until a sign/event happens
what are the functions and key features of the mitochondria?
MITO: generate and gives out large amounts of energy.
body is composed of :
-outer membrane: Smooth surface contains porin (pores)
-Intermembrane space membrane
-inner membrane : is folded in shelf like called cristae Inside is the matrix ( viscous fluid, containing protien involved in fatty acid oxidation and the Krebs cycle.) Cardiolipin: a phospholipid found in the Inner Mem. make it impermeable to ions, electrons and protons.
Functions
- generate ATP
- generate heat
- help with making certain lipids and protiens
- have proper enzymes of TCA cycle
- take part in apoptosis
what is the ER and what are its functions?
ER: flat sheets of membrane that occupy much of the intercellular space
2 types
-sER: plays a part in making cholesterol and lipid and detox. of cetian drugs and toxins
*in skeletal muscle the sER sequester and relases Ca+ ions
-rER: Membrane bound flattened sacs called cisterns that habe ribosomes attached on the external surface. synthesis and modification of proteins that are packaged as well as in the synthesis of membrane lipids and protiens.
The GA : phosphorylation and glycosylation of proteins ( protein sorting)
what are endosomes and there funtions.
Endosomes: concerned with the destruction of endocytosed,phagocytosed, or autophagocytosed material and formation of lysosomes. have a proton pump.
- 2 types of :*
- -Early endosomes:* located close to cell membrane. have receptor-ligand complexes acidic pH uncouples the receptors (sent to the plasmalemma) from the ligand( sent to late endosomes)
- -Late endosomes:* Mature into lysosomes and possess a high acidic pH
How are lysosomes made, and what diseases are associated with lysosomal storage disease?
Formation of lysosomes are by using of late endosomes as middle step.
- Both lysosomal membranes and lysosomal enzymes are packaged in the Trans Golgi Network
- Are delivered in separate clathrin coated vesicles to late endosomes, forming endolysosomes which mature into lysosomes .
- Lysosomes are rich in hydrolytic enxymes ( breaks bond in the presence of water)
- resposible in break down of phagocytosed material and certain molecules.
LYSOSOMAL STORAGE DISEASES
“dysfuntionla lysosomes that cannot degrade content of their endolysosomes.”
-TAY-SACHS DISEASE:•occurs mostly in children whose parents are descendants of Northeast European Jews
function of peroxisomes, and what disorder is associated with Peroxisomes ?
Peroxisomes :single membrane-bound organelles that contain oxidative enzymes e.g urate oxidase, catalase, D- amino glucosidase.All oxidative enzymes produce hydrogen peroxide (H₂O₂), which is a toxic substance.
-Catalase regulates amount of peroxide thus protecting the cell.
Disorder:
Zellweger’s Syndrome: Is an inherited autosomal recessive disorder that interferes with normal peroxisomal functions which lead to an early death.
Non – membranous Organelles are …….
1.Ribosomes :
- •Are small non membranous organelles that exist as individual particles until protein synthesis begins .
- •There are 2 subunits of unequal size and constitution , composed of proteins and r-RNA. The large sub unit is 60 S in size and the small unit is 40 S.
Cytoskeleton:•filamentous proteins that act not only as the structural frameworkof the cell but also to transport material within the cell and provide it with the capability of motionand cell division .
Microtubules :Consist of alpha and beta tubulins arranged in 13 protofilaments.
A. Thin filaments: actin and microfilament help in the movement of the cell from one place to another.
B.Intermediate filaments: providing structural framework to the cell and resist mechanical stress.
C. Think filaments : work with thin filaments by providing movement.
Microfilaments
Centrioles :Provide basal bodies for cilia and flagella and align the mitotic spindle during cell division, found close to nucleus surrounded by GApparatus.
Cell Cycle.
-A number of t_rigger_ proteins , known as cyclins and cyclin dependent kinases control the cell cycle.
- Cell division is a crucial process that increases the number of cells & permits renewal of cell population. ( mitosis ) Bacteria use this to reproduce asexually
- Meiosis involves 2 sequential nuclear divisions followed by cell divisions that produce gametes containing half the number of chromosomes and half the DNA found in somatic cells. reproduce sexually.
