cell and organelles

Question 1

define the following

1. histology
2. histopathology

Answer 1

1. histology-study of microscopic structures of normal tissues
2. histopathology-is the microscopic study of diseased tissues

unless you know the normal histology, you cannot discuss the diseased state of cell

Question 2

The cytoplasm and nucleus are components _________. define this term

Answer 2

protoplasm

1. houses the living components of the cells
   
   1. organelles
2. living and nonliving
   
   1. nonliving are inclusions
      
      1. crystals and pigments
      2. lying in the cytorplasmic matrix

Question 3

organelles can be categorized into two group. Define the two and components of each

Answer 3

membranous organells

1. the plasma (cell) membrane
2. rER
3. sER
4. golgi
5. endosomes
6. lysosomes
7. transport vesicles
8. mitochondria

non-membranous organelles

1. microtubules
2. filaments
3. centrioles
4. ribosomes

Question 4

define the dna compartment of the cell

1. four notable parts
2. analysis of this assists with understanding some thing about the cell as a whole

photo is general reference

Answer 4

nucleus

1. interphase-non dividing cell (normal state)
   
   1. choromatin
   2. nucleolus
   3. nucelar envelop
   4. nucleoplasm
2. provides best health of a cell

organ composition

1. nuclear evelope
   
   1. inner/outer nuclear envelope, and perinuclear cistern (space between layers
2. nuclear pore complex- regulate transport of substances between nuclear space an cytosol
   
   1. nuclear pore
      
      1. location where the internal and external layers come into contact
   2. protein guards
      
      1. 3. chromatin- two states
   3. heterchormatin- dense
      
      1. clumped toward the periphery of the cell
   4. euchromatin
      
      1. expressed DNA
3. nucleolous-spherical structureinvolved in transcription of genes coding for ribosomal RNA and assembly of ribosomal units
   
   1. stains intensly with hemetoxylin dye

Question 5

what type of test looks at the chromosome composition?

Answer 5

1. cytogeneitic testing
   
   1. important diagnostic and evaluation of geneticdisorders and revers to analysis of chromosomes

Question 6

the plasma membrane has three main ways to mantain concentration of molecules. list the three and appropriate associated proteins.

Answer 6

1. simple diffusion-no proteins
   
   1. fat soluble and small uncharged molecules travel through the plasma membrane
2. carrier proteins
   
   1. transfer small water soluble molecules
      
      1. uniport-highly selective
      2. coupled transport-transport in concert
      3. symport-substances travel in same direction
      4. antiport-substances travel in opposite direction
      5. active transportation-transport against gradient with energy currency (ATP)
3. channel proteins
   
   1. ions and other small charged molecules are transported through the plasma membrane by ion-selective channel proteins
      
      1. neuron
         
         1. ion transport is regulated by membrane potentials (voltage gated ion channels)
      2. skeletal muscle
         
         1. neuromuscular junctions possess ligand gated ion channels

no energy is used to transport glucose accross***

Question 7

what is the main process by which particles enter or leave the cell?

Answer 7

vesicle budding

1. inbudding- endocytosis
   2.

Question 8

The two types of movment accross the plasma membrane have three purposeful ways of entering and two for leaving.

Answer 8

1. endocytosis
   
   1. pinocytosis
      
      1. non specific ingestion of fluid and small protein molecules via small vesicles
   2. phagocytosis
      
      1. uptake of particular matter
   3. receptor mediated endocytosis-LDL
2. exocytosis
   
   1. constitutive secretion
      
      1. substances designated for export are continuouslt delivered in transport vesicles to the plasma membrane
         
         1. procollagen- formed by fibroblast and continue to secrete procollagen
   2. regulated secretion
      
      1. specialized cells such endocrine, exocrinve cells and neurons, concentrate secretory proteins and transiently store them in vesicles with in the cytoplasm. A regularoy event (hormonal or neural stimulus ) must be activated for secretion to occur
         
         1. as in the release of secretion by the acinar cells of pancreas
            
            1. produces pancreatic juice, which is stored as zymogen granules and secreted when stimulated.

Question 9

The energetic organelle has two membranes. name this organelle, constituents in the layers and functions.

Answer 9

1. mitochondria
   
   1. membrane
      
      1. outer-permeable to ions and e-
         
         1. porins- large channels that allow larger particles to pass from cytoplasm to cell
            
            1. hence the composition of intermembranous space is similar to cytoplasm
      2. inner-impermeable
         
         1. cristae
            
            1. shelf like projections
            2. enclose the matrix
         2. matrix
            
            1. contains proteins involved in fatty acid oxidation and krebs cycle
            2. viscous fluid containing high concentration of proteins some of which are involved in FAOx
         3. cytochromes
         4. atp synthases
         5. cardiolipin
            
            1. phospholipid making the inner membrane impermeable to ions, electrons and protons
   2. function
      
      1. generation of ATP
         
         1. TCA
      2. heat
         
         1. brown fat
      3. lipid synnthesis
      4. apopsosis

Question 10

Discuss mitochondrial inheritance

how does this play in disease progression and manifestation?

Answer 10

1. inherited mitochondrial diseases do not follow mendelian genetics
2. maternal inheritance
3. replicate independently from the rest of the cell
4. both males and females can be affeted by mitochondrial disease but males never trasmit disorder
   
   1. muscular distrohpies
   2. optical neuropathy

Question 11

this organelle has pivitol part in protein and lipid synthesis. list two types, structures and functions

Answer 11

endoplasmic reticulum

1. structure
   
   1. consists of tubules, sacs and flat sheets of membranes that occupy much of the intracellular space
2. types
   
   1. smooth ER
      
      1. function
         
         1. synthesis of
            
            1. cholesterol
            2. lipids
         2. detoxification of
            
            1. drugs
            2. toxins
         3. skeletal muscle sequesters and releases Ca2+
   2. rough ER
      
      1. structure
         
         1. series of interconnected cisterns
            
            1. membrane bound flattened sacs
         2. these cisterns have ribosomes attached on the external surface of the mebrane
      2. function
         
         1. synthesis and modification of
            
            1. proteins
            2. membrane lipids
            3. membrane proteins

Question 12

this organelle is imperative for sorting and is transiently located around the cell.

1. location
2. structure -faces
3. function
4. microscopy

Answer 12

golgi apparatus

1. location
   
   1. near nucleus
2. structure
   
   1. stack of vesicles, tubules, and flattened membranous bound cisterns.
   2. three faces
      
      1. cis face
         
         1. ​convex entry face located near the nucleus
      2. medial face
         
         1. in between the cis face and trans face
      3. trans face
         
         1. concave exit face located towards the cell membrane
3. function
   
   1. phosphorylation and glycosylation of proteins
   2. protein sorting
      
      1. ​incorporated into a unit membrane
         
         1. plasmalemma-integral proteins
      2. immediate release into extracellular space
      3. intracellular storage within secretory vesicles to be released late on
      4. incorporated into lysosomes in the cytoplasm
4. microscopy
   
   1. does not stain with H&E stains

Question 13

Describe two stages in the structure that takes in extracellular material.

Answer 13

endosomes

1. structure
   
   1. two types-
      
      1. early endosomes- from the cytoplasm
         
         1. contain receptor-ligand complexes and their acidic pH (6) uncouples the receptors from the ligand. Contain proton pumps lower pH
      2. late endosomes
         
         1. mature into lysosomes and possess a really low pH
2. function
   
   1. ligand complexes are taken in to the cell with the foreign material. proton pumps lower pH. receptor are sent to the plasmalemma and the ligand is send to the late endosome. late endosomes for m
3. location
4. microscopy

Question 14

Golgi generates something that meets another vesicle in the cytosol. discuss this interesting relationship, development/maturation and structures of importance inside.

Answer 14

lysosomes

1. generation
   
   1. formed by use of late endosomes as an intermediary compartment
   2. lysosomal membranes and lysosomal enzymes are packaged in the trans golgi network
   3. delivered in separate clathrin coated vesicles to late endosomes, form endolysosomes which mature into lysosomes
2. contents
   
   1. rich in hydrolytic enzymes- all responsible for degradation of certain molecules and phagocytosed material
      
      1. proteases
      2. nuclease
      3. lipases

Question 15

jimmy is brought to his pediatrician after his parents noticed problems with coordination, rythmic muscle contractions and other neurologically related issues. If he descends from northeast european Jews population, what could the possible disease be?

describe cause, function/mechanism

Answer 15

1. tay-sach disease
   
   1. dysfunctional lysosomes that are unable to degrade the contents of their endolysosomes
   2. cause
      
      1. mutations on genes that encodes lysosomal proteins.
   3. function
      
      1. lysosomes are unable to catabolize GM2 ganglioside
      2. due to hexoaminodase deficiency their neurons accumulate large amount of ganglioside in endolysosomes.
      3. the enlarged endolysosomes obstruct neuronal function

Question 16

an important membranous organelle focuses on ROS production.

what are this organelles contents and function. What happens when this structure is genetically modified?

Answer 16

peroxisomes

1. contents
   
   1. membrane bound organelle
   2. contains
      
      1. oxidative enzymes
         
         1. urate oxidase
         2. catalase
         3. D-amino glucaosidase
2. function
   
   1. oxidative enzymes generate environment rich in ROS (H2O2)
   2. catalase present in peroxisomes regulates the amount of hydrogen peroxide, protecting the cell from rupture
3. disease
   
   1. Zellweagers syndrome
      
      1. autosomal recessive disorder
      2. malfunction
         
         1. peroxisomal functions do not operate normally
      3. outcome
         
         1. early death-b/c of cell death

Question 17

what is the composition of ribosomes

Answer 17

ribosomes

1. composisition
   
   1. 60S and 40S- proteins and rRNA

Question 18

define the cytoskeleton and give the five organelle examples

Answer 18

cytoskeleton- non membranous organelles

1. types
   
   1. microtubues
      
      1. composition
         
         1. alpha and beta tubulins arranged in 13 protofilaments
      2. MAPs
         
         1. two important types
            
            1. kinesin
            2. dynein
   2. microfilaments
      
      1. a type of thin filament
      2. function
         
         1. help in the movement of cell from one place to another. Movement to the regions of cell with respect to itself
   3. intermediate filaments
      
      1. help in providing a structural framework to the cell and resist mechanical stresses on the cells
   4. thick filament
      
      1. made of myosin and interact with thin filaments providing mevement
   5. centrioles
      
      1. composition
         
         1. short rod like structure built from nine microtubule triplets
      2. location
         
         1. close to the nucleaus often partially surrounded by golgi apparatus
      3. function
         
         1. provide basal bodies for cilia and flagella
         2. align the mitotic spindle during cell division

Question 19

two important types of cell replication.

what controls them?

cell homeostasis is a well balanced system list a few of the following and explain general reason by categorizing these diseases:

1. cell loss disorders
2. cell accumulation disorders

Answer 19

1. mitosis and meiosis
2. controlled by cyclins- trigger proteins
   
   1. controled by cyclin dependent kinase
   2. function
      
      1. crucial for mitosis/meiosis

Question 20

irreversible condensation of a chromatin

Answer 20

pyknosis, part apoptosis. followed by karryorexis (cell rupture)