Cells Flashcards
What are tissues?
Cells that carry out the same general function and are grouped together
What are the four basic tissues?
Epithelia, connective tissue, muscle, and nerve
What is the function of epithelia?
To cover and line surfaces (ex. lumen)
What is the function of connective tissue?
To package, support, and connect
What is the function of muscle tissue?
Contractility (ex. change size of lumen for smooth muscle)
What are the types of muscle tissue?
Skeletal, cardiac, and smooth
What is the function of nerve tissue?
irritability and conduction
Definition of Resolution
Ability to see two side-by-side dots as separate entities
What is the resolution of the unaided human eye?
~0.2mm
Why stain tissue?
To enhance contrast in cell and be able to identify structures
What are tissue components that stain with basic dyes called?
Basophillic
What are tissue components that stain with acidic dyes called?
Acidophilic
What are examples of basic dyes?
Toluidine blue, methylene blue, and hematoxylin
What are examples of acidic dyes?
Eosin and fuchsin
Are DNA and RNA acidic or basic?
Acidic
In general, what can you see in a LM section?
Only cell, nucleus, and nucleolus / cannot see organelles
In Trichrome stain, _______ always stains blue/green.
Connective Tissue
What chemicals make up a Golgi stain?
Potassium dichromate and silver nitrate
What does Sudan Black stain?
Lipids (aka adipocytes)
What does periodic acid schiff (PAS) reaction stain magenta?
Carbohydrates (glycoproteins, goblet cells, etc. )
What color does hematoxylin stain?
Blue
What color does eosin stain?
Pink
Is the mitochondria acidic or basic?
Basic
What is a parenchyma?
Functional tissue of an organ
What is the use of fluorescent immunochemistry?
to identify proteins in cell and tissues
What is an epitope?
Area recognized by the antibody
What are the steps of Fluorescent Immunochemistry?
1) Identify cell with target antigen
2) Incubate tissue with primary antibody that binds to epitope
3) Incubate with secondary antibody that binds to primary antibody with a fluorescent tag
4) See under microscope
This dye is responsible for staining carbohydrates is…
Periodic Acid Schiff Reaction
Concept of plane of section
Where you cuts affects what you see
What is a transmission electron microscope?
Electron beam passed through very thin section of tissue
Dark areas in a TEM are called….
Electron dense
Light areas in a TEM are called…
Electron Lucent
What is a scanning electron microscope (SEM)?
Electron microscope that shows the 3D surface of a cell (more depth than TEM)
Electron microscopy uses what dye?
Osmium tetroxide
What is the nucleus?
Archive of the cells that produces informational molecules
Differentiate between euchromatin and heterochromatin
Euchromatin is light part and active DNA
Heterochromatin is dark part and inactive DNA
Which type fo DNA is transcribed into mRNA?
Euchromatin
What type of cisterna separates the inner nuclear envelope from the other nuclear envelope that bears ribosomes?
Perinuclear cisterna
What helps support the nucleus and aids in maintaining its shape?
LAMINS
What are lamins?
Support structures of intermediate filaments that “coat” the inner surface of the nucelar membrane and where chromosomes attach (nuclear lamina)
How does DNA fit in a nucleus?
DNA wraps around histones to fit in a helical coil of nucleosomes
DNA coiled around a histone is called a ________
Nucleosome
Characteristics of a nucleolus
- spherical
- acidic (basophilic)
- contains proteins and rRNA
What structure allows for transport in/out nucleus
nuclear pores
Nuclear pores require what type of transport for molecules over 9nm?
ACTIVE
Nuclear pores are made of…
proteins
Macromolecules transport across NPCs through a ____ pore
Aqueous
Nuclear localization signal on proteins is recognized by…
Nuclear import receptor (NIR)
How does cargo protein move through the nuclear pores?
- Nuclear import receptors (NIR) binds to nuclear localization signals (NRS) and to fibrils of the NPC
- Cargo moves through the pore by binding and dissociating again to proteins that line nuclear pore
- Inside nucleus NIR dissociates from cargo and returns to cytosol
Cisternae Defintion
A fluid-containing sac or cavity bounded by membrane (in ER and Golgi)
Lamellar Definition
Sheets stacks adjacent to each other with fluid or matrix in between
Cristae vs. Cisternae
Cristae are foldings of the inner mitochondrial membrane, while Cisternae are flattened structures of ER and Golgi
Lamellar and cristae serve what purpose in the mitochondria
Increase surface area
Which membranes of the mitochondria are restrictive versus permeable?
Outer membrane is permeable
Inner membrane is very restrictive
Mitochondria are located where in the cell?
Where energy requirements are high in the cell
Mitochondria undergo _____.
Fission
What percent of mitochondria uses its own DNA for proteins?
20% –> believed to be derived from bacteria
Is DNA synthesized in the mitochondrion independent of nuclear DNA?`
mitochondrial DNA is independent of nuclear DNA
Both mitochondria and endoplasmic reticulum are involved in …
uptake, storage, and release of calcium
Where are enzymes stores in mitochondria?
on membranes of cristae
Mitochondria and peroxisome are both involved in…
Beta oxidation of long chain fatty acids
Which two structures in cell are involved in beta oxidation of long chain fatty acids?
mitochondria and peroxisome
What are functions of the mitcochondria?
- energy production (chemical energy to ATP)
- beta oxidation of long chain fatty acids
- uptake, storage, and release of calcium
- steroid hormone synthesis (side chain cleavage)
More cristae means more…
more surface area for energy production –> needed in cells that require large amounts of energy
All steroids are derived from…
cholesterol
1st step of steroid hormone synthesis is…
Side chain cleavage of cholesterol which happens in mitchondria
What enzyme is involved in side chain cleavage on the inner mitochondrial membrane?
Desmolase
What is the role of calcium granules in the mitochondria?
help regulate function (ATP production)
Side chain cleavage ends with what molecule?
Pregnenolone
What is pregnenolone?
precursor to certain steroids (progesterone, aldosterone, testosterone, etc.)
Which organelle synthesizes steroid hormone after side chain cleavage?
Smooth ER
Ribosomes are the site of…
protein synthesis
Which part of the mitochondria is responsible for TCA cycle?
Matrix
What is the purpose of the calcium granule?
to increase ATP production
Where is the side of side chain cleavage?
Inner mitochondrial membrane
RER is continuous with what two structures?
Nuclear envelope and SER
RER is full of …
ribosomes that connect with perinuclear cisternae
RER stains what color?
Blue
RER stain intensely with basophilic dyes such as hematoxylin because it is acidic
What are polyribosomes and where are they found?
ribosomes associated with mRNA, which occur in cytosol or RER membranes
What are the functions of the RER?
Protein synthesis
Constitutive vs regulated secretion definition
Constitutive = occurs all the time
Regulated = needs signal to secrete
What is the function of secretion granules and where are they located?
Storage for proteins and are usually at apex of cell until needed
What are the functions of SER?
- Steroid Synthesis
- uptake and release of calcium in muscle cells (sim to mitochond)
- synthesis and breakdown of glycogen
- detoxification of drugs
- formation of lipoproteins
- production of bile
SER is abundant in which tissues?
cardiac and skeletal muscle cells
What is the function of the golgi complex?
post-translational protein modification (ex. glycosylation, sulfation, etc)
In the Golgi complex, proteins and lipids enter in the _____ and exit through the _____
enter cis face; exit trans face
Which stain do you use to identify cis face of Golgi?
osmium reduction
Which stain do you use to identify trans face of Golgi?
acid phosphatase
What happens if a protein does not work?
Proteasomes break it down
what is the importance of glycosylation?
correct folding of protein, protect from degradation, and signaling
What are lyosomes?
membrane bound organelles that degrade worn out structures in cell
Are lysosomes heterogeneous or homogenous in content?
heterogeneous
What are functions of lysosome?
degredation of bacteria, degrading worn out organelles, break down of bone during bone remodeling
How are lysosomes formed?
1) hydrolytic enzymes are formed in RER
2) enzymes have terminal mannose-6-phophate marker (M6P) added at Cis-Golgi
3) packaged at Trans-Golgi
4) vesicles are now early endosomes –> fuse with other vesicles to form late endosomes/lysosomes
Lysosomes contain what type of enzymes?
Hydrolytic
Lysosome enzymes are only found in what kind of environment?
ACIDIC
Definition of senescent cell
Dying cell
Lysosomal membrane contains a ____ which maintains the acidic interior of the organelle
proton pump
What in the lysosome keeps it from oxidizing its environment?
phospholipid bilayer
If bone formation decreases, leads to…
osteoporosis - bones become weak and brittle
if bone formation increases, leads to…
osteopetrosis (bones growing abnormally)
What is an example of a lysosomal storage disease?
Tay Sach’s Disease: fatty substance build up in the brain
What are symptoms of Tach Sach’s disease?
- neuromuscular symptoms
- absence of beta-hexosaminidase enzyme
slower growth in children - bone-joint deformaties
- enlarged internal organs
Proteasomes recognize proteins with what kind of molecules?
Ubiquitin
What are proteasomes?
organelles that deal with proteins as individual molecules and aren’t membrane bound
EDIT: NOT AN ORGANELLE! (complex of proteins)
What is ubiquitin?
marker of correct folding for proteasome to reognize
Are peroxisomes organelles?
NO they are MICROBODIES
What enzymes do peroxisomes contain?
oxidative enzymes and catalase
What are functions of peroxisomes?
Lipid metabolism (beta oxidation of long chain fatty acids) and degradation of hydrogen peroxide
How are peroxisome enzymes made?
protein made by RER and goes directly to peroxisome NOT through Golgi
What disease results from no beta-oxidation of FA in peroxisomes?
Zellweger’s Syndrome
What causes Zellweger’s Syndrome?
Enzyme made but not importing properly that causes babies to have high levels of low density glycoprotein
What are symptoms of Zellweger’s syndrome (Cerebrohepatorenal syndrome)?
- muscle and nerve damage
- babies are hypotonic (can’t hold themselves up)
- cause breakdown of myelin –> causes accumulation of toxic sub
- inability to nurse properly
- rare, autosomal
What are examples of inclusions?
Glycogen, lipofusion, lipid droplets
Where is glycogen enzymes synthesized?
SER
What is lipofusion?
yellow-brown pigment granules that accumulates with age (found in dying cells)
What are lipid droplets?
Lipid droplets are energy storage and a source of lipids which may be used in steroid hormone formation (not membrane bound)
What is the glycocalyx?
a carbohydrate sugar coat that surrounds the entire cells
- appears as fuzz on surface of microvilli
why do cells have membrane-bound compartments?
to maintain optimal concentration of biomolecules in/out of the compartments, provide a physical barrier, and separate to ensure specific processes can occur functionally
What is cytosol and what is in it?
fluid present in cell membrane (ions, H2O, proteins, etc.)
